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Background: The European Society of Anesthesiology and Intensive Care recommends the use of neuromuscular blocking agents (NMBA) in adults, to facilitate tracheal intubation and reduce its associated complications. Children who undergo tracheal intubation may suffer some of the same complications, however, no consensus exists regarding the use of NMBA for tracheal intubation in the pediatric population. We will explore the existing evidence assessing the effects of avoidance versus the use of NMBA for the facilitation of tracheal intubation in children and infants. Methods: This protocol follows the preferred reporting items for systematic reviews and meta‐analyses protocols recommendations. We will include all randomized controlled clinical trials assessing the effects of avoidance versus the use of NMBA for facilitation of tracheal intubation (oral or nasal) using direct laryngoscopy or video laryngoscopy in pediatric participants (<18 years). Our primary outcome is incidence of difficult tracheal intubation. Secondary outcomes include incidence of serious adverse events, failed intubation, events of upper airway discomfort or injury, and difficult laryngoscopy. We will conduct a thorough database search to identify relevant trials, including CENTRAL, MEDLINE, EMBASE, BIOSIS, Web of Science, CINAHL, and trial registries. Two review authors will independently handle the screening of literature and data extraction. Each trial will be evaluated for major sources of bias with the "classic risk of bias tool" used in the Cochrane Collaboration tool from 2011. We will use Review manager (RevMan) or R with the meta package to perform the meta‐analysis. We will perform a trial sequential analysis on the meta‐analysis of our primary outcome, providing an estimate of statistical reliability. Two review authors will independently assess the quality of the body of evidence using the grading of recommendations assessment, development, and evaluation (GRADE) approach. We will use GRADEpro software to conduct the GRADE assessments and to create "Summary of the findings" tables. [ABSTRACT FROM AUTHOR]

Introduction: Unanticipated difficult airway is still a cause of morbidity and mortality. Various parameters are used to predict difficult airways. Recent studies have found that measuring the Sternomental Displacement (SMDD) can help establish a difficult airway. Aim: To find whether the Ratio of Height to Sternomental Displacement (RHSMDD) could be used as a predictor for Difficult Laryngoscopy (DL) and intubation. Secondary objectives included comparing RHSMDD with routine assessment parameters like Modified Mallampati Score (MMT), SMD, Thyromental Distance (TMD), and Inter Incisor Distance (IID). Materials and Methods: A prospective observational study was conducted at Malabar Medical College, Calicut, Kerala, India among 120 adult patients undergoing elective surgeries under general anaesthesia. Airway parameters like MMT, IID, TMD, SMD, Sternomental Displacement (SMDD), RHSMDD, Ratio of Height to Sternomental Distance (RHSMD), and Ratio of Height to Thyromental Distance (RHTMD) were measured preoperatively and associated with Cormack Lehane’s laryngoscopic grading and Intubation Difficulty Scale (IDS) value. A comparison of airway parameters with laryngoscopy and intubation was done by the Mann-Whitney U test. Receiver Operating Characteristics (ROC) curves were constructed, and optimal cut-off values for significant quantitative indices were calculated. Sensitivity, specificity, Positive Predictive Value (PPV), and Negative Predictive Value (NPV) were also calculated and compared. Results: The incidence of DL was 27.5%, and Difficult Intubation (DI) was 10.8%. Age (p-value=0.013), weight (p-value=

Abstract Background The main cause of anesthesia-related deaths is the failure to manage difficult airways. Difficult laryngoscopic exposure is a major cause of unsuccessful management of difficult airways. Inadequate preoperative airway assessment hinders the clinical management of difficult airways cases, emphasizing the critical need for accurate identification of difficult airways. Currently, no definitive and reliable indicators are available to predict a difficult airway. Our study aims to predict laryngoscope exposure risk factors by combining ultrasonically measured upper airway anatomic parameters with physical examination indicators. Methods Patients aged 18 to 75 years, classified as American Standards Association (ASA) I-III, and scheduled for elective general anesthesia with endotracheal intubation were included. All patients received the upper airway and ultrasonographic measurements. After anesthesia induction, laryngoscope exposure was analyzed using the Cormack-Lehane grading system, with Grades III and IV as indicative of difficult laryngoscopy. Univariate and multivariate logistic regression analyses were performed to identify reliable indicators for predicting difficult laryngoscopy. Receiver Operating Characteristic (ROC) curve analysis was utilized to assess the predictive performance of each indicator. Results A total of 1120 patients finished the study, with 710 cases found in Grade I laryngoscopic exposure group, 360 cases in Grade II group, and 50 cases in Grade III group. There was no case observed in Grade IV group, thereby resulting in an incidence of difficult laryngoscopy of 4.46%. Univariate logistic regression analysis revealed that several parameters including age, Body Mass Index (BMI), neck circumference, neck mobility, snoring intensity, as well as ultrasound measurements of the pre-epiglottic space and thyromental distance were identified as significant risk factors for difficult laryngoscopy (P

Background: Several clinical tools are used for preoperative airway assessment. Ultrasound is an emerging tool in anesthesia, and its role in the upper airway needs to be explored. Aims and Objectives: We aimed to assess the role of airway ultrasound in predicting difficult laryngoscopy and airway changes following induction of anesthesia. Materials and Methods: Clinical airway assessment was performed with a modified Mallampati score in 100 elective surgical patients. Ultrasound variables in pre- and post-induction of anesthesia were: distance between the skin and vocal cords at the hyoid bone (DSVC hb), distance from the skin to the thyroid isthmus, distance from the skin to the tracheal ring at suprasternal notch level, and distance between the skin and the cricothyroid (DSCM). Cormack–Lehane (CL) grades 3b and 4 were classified as having a DL. Association of clinical, ultrasonography (USG) indicators and CL grading was correlated. Dynamic changes in anterior neck tissues following induction of anesthesia were also measured. Results: Pre-induction USG variables were significantly higher in the DL group compared to the NDL group (P

Background: The main cause of anesthesia-related deaths is the failure to manage difficult airways. Difficult laryngoscopic exposure is a major cause of unsuccessful management of difficult airways. Inadequate preoperative airway assessment hinders the clinical management of difficult airways cases, emphasizing the critical need for accurate identification of difficult airways. Currently, no definitive and reliable indicators are available to predict a difficult airway. Our study aims to predict laryngoscope exposure risk factors by combining ultrasonically measured upper airway anatomic parameters with physical examination indicators. Methods: Patients aged 18 to 75 years, classified as American Standards Association (ASA) I-III, and scheduled for elective general anesthesia with endotracheal intubation were included. All patients received the upper airway and ultrasonographic measurements. After anesthesia induction, laryngoscope exposure was analyzed using the Cormack-Lehane grading system, with Grades III and IV as indicative of difficult laryngoscopy. Univariate and multivariate logistic regression analyses were performed to identify reliable indicators for predicting difficult laryngoscopy. Receiver Operating Characteristic (ROC) curve analysis was utilized to assess the predictive performance of each indicator. Results: A total of 1120 patients finished the study, with 710 cases found in Grade I laryngoscopic exposure group, 360 cases in Grade II group, and 50 cases in Grade III group. There was no case observed in Grade IV group, thereby resulting in an incidence of difficult laryngoscopy of 4.46%. Univariate logistic regression analysis revealed that several parameters including age, Body Mass Index (BMI), neck circumference, neck mobility, snoring intensity, as well as ultrasound measurements of the pre-epiglottic space and thyromental distance were identified as significant risk factors for difficult laryngoscopy (P < 0.05). Among these, BMI, and neck circumference exhibited notable predictive value, with Area Under The Curve (AUC) values of 0.746 (95%CI 0.649–0.842) and 0.732 (95%CI 0.638–0.827), respectively. Neck mobility was also identified as an independent risk factor for predicting difficult laryngoscopy (P = 0.009) in multivariate logistic regression analysis, with an AUC of 0.672 (0.562–0.782) in the ROC curve. Conclusions: Our findings revealed a direct correlation between difficult laryngoscopy and age, BMI, neck circumference, neck mobility, snoring intensity, as well as ultrasound measurements of the pre-epiglottic space and thyromental distance. Furthermore, neck mobility was identified as an independent predictive factor. Trial registration: The trial was registered prior to patient enrollment at clinicaltrials.gov (register no. ChiCTR2100053826, Date of registration: November 30, 2021). [ABSTRACT FROM AUTHOR]

Summary: While videolaryngoscopy has resulted in better overall success rates of tracheal intubation, airway assessment is still an important prerequisite for safe airway management. This study aimed to create an artificial intelligence model to identify difficult videolaryngoscopy using a neural network. Baseline characteristics, medical history, bedside examination and seven facial images were included as predictor variables. ResNet‐18 was introduced to recognise images and extract features. Different machine learning algorithms were utilised to develop predictive models. A videolaryngoscopy view of Cormack‐Lehane grade of 1 or 2 was classified as 'non‐difficult', while grade 3 or 4 was classified as 'difficult'. A total of 5849 patients were included, of whom 5335 had non‐difficult and 514 had difficult videolaryngoscopy. The facial model (only including facial images) using the Light Gradient Boosting Machine algorithm showed the highest area under the curve (95%CI) of 0.779 (0.733–0.825) with a sensitivity (95%CI) of 0.757 (0.650–0.845) and specificity (95%CI) of 0.721 (0.626–0.794) in the test set. Compared with bedside examination and multivariate scores (El‐Ganzouri and Wilson), the facial model had significantly higher predictive performance (p < 0.001). Artificial intelligence‐based facial analysis is a feasible technique for predicting difficulty during videolaryngoscopy, and the model developed using neural networks has higher predictive performance than traditional methods. [ABSTRACT FROM AUTHOR]

Good glottic exposure is a prerequisite for a good microlaryngeal surgery. Often this is difficult to predict preoperatively. This study aims to evaluate the utility of office-based rigid laryngoscopy (70°) as a screening tool to predict laryngeal exposure during micro laryngoscopy. Sixty-nine patients underwent office-based rigid laryngeal examination followed by micro laryngoscopic surgery for benign vocal cord lesions. Office-based laryngoscopy was classified as grade 1 when the entire glottis with anterior commissure (AC) was visualized without undue traction of tongue; grade 2 when AC was visualized only during phonation and with some traction of tongue and grade 3 when there is an inability to visualise the glottis adequately despite moderate traction of tongue and the examination was completed using a flexible scope. These were correlated with laryngeal exposure during micro laryngoscopy. 42 patients were categorized as grade 1 out of which 39 (93%) had a favourable laryngeal exposure (class 1) while only 3 (7%) had a partially favourable exposure (class 2). 18 patients were categorized as grade 2 out of which 12(66%) had a favourable exposure (class 1) as against 6 (33%) who had a partially favourable exposure (class 2). Nine of our patients were categorized as grade 3 out of which all 9 (100%) had an unfavourable exposure (class 3) requiring angled tele laryngoscopy to complete the surgery. A strong correlation between office-based laryngoscopic grading and exposure during operative laryngoscopy was obtained statistically (Cramer's V test, V = 0.746). Office examination with a 70° telescope is a good predictor of glottic exposure during micro laryngoscopy. We believe that the ease of performing a micro laryngoscopy in the operating room is directly proportional to the ease of doing laryngoscopy in the office. [ABSTRACT FROM AUTHOR]

Background: Several clinical tools are used for preoperative airway assessment. Ultrasound is an emerging tool in anesthesia, and its role in the upper airway needs to be explored. Aims and Objectives: We aimed to assess the role of airway ultrasound in predicting difficult laryngoscopy and airway changes following induction of anesthesia. Materials and Methods: Clinical airway assessment was performed with a modified Mallampati score in 100 elective surgical patients. Ultrasound variables in pre- and post-induction of anesthesia were: distance between the skin and vocal cords at the hyoid bone (DSVC hb), distance from the skin to the thyroid isthmus, distance from the skin to the tracheal ring at suprasternal notch level, and distance between the skin and the cricothyroid (DSCM). Cormack–Lehane (CL) grades 3b and 4 were classified as having a DL. Association of clinical, ultrasonography (USG) indicators and CL grading was correlated. Dynamic changes in anterior neck tissues following induction of anesthesia were also measured. Results: Pre-induction USG variables were significantly higher in the DL group compared to the NDL group (P<0.05), except DSCM. Post-induction all USG parameters were significantly higher in the DL group. Among USG variables, DSVC hb and DTSI had the highest AUCs of 0.801 and 0.772, respectively. DSVC hb had a sensitivity of 76% and a specificity of 100% for DL. DTSI had a sensitivity of 92% and a specificity of 72%. There was a significant increase in depth after anesthetic induction of all USG parameters except DSCM. Conclusions: Ultrasound of anterior airway tissues can be considered for prediction of DL and allows dynamic airway assessment. [ABSTRACT FROM AUTHOR]

Abstract Background Identification of difficult laryngoscopy is a frequent demand in cervical spondylosis clinical surgery. This work aims to develop a hybrid architecture for identifying difficult laryngoscopy based on new indexes. Methods Initially, two new indexes for identifying difficult laryngoscopy are proposed, and their efficacy for predicting difficult laryngoscopy is compared to that of two conventional indexes. Second, a hybrid adaptive architecture with convolutional layers, spatial extraction, and a vision transformer is proposed for predicting difficult laryngoscopy. The proposed adaptive hybrid architecture is then optimized by determining the optimal location for extracting spatial information. Results The test accuracy of four indexes using simple model is 0.8320. The test accuracy of optimized hybrid architecture using four indexes is 0.8482. Conclusion The newly proposed two indexes, the angle between the lower margins of the second and sixth cervical spines and the vertical direction, are validated to be effective for recognizing difficult laryngoscopy. In addition, the optimized hybrid architecture employing four indexes demonstrates improved efficacy in detecting difficult laryngoscopy. Trial registration Ethics permission for this research was obtained from the Medical Scientific Research Ethics Committee of Peking University Third Hospital (IRB00006761-2015021) on 30 March 2015. A well-informed agreement has been received from all participants. Patients were enrolled in this research at the Chinese Clinical Trial Registry ( http://www.chictr.org.cn , identifier: ChiCTR-ROC-16008598) on 6 June 2016.

Background: Identification of difficult laryngoscopy is a frequent demand in cervical spondylosis clinical surgery. This work aims to develop a hybrid architecture for identifying difficult laryngoscopy based on new indexes. Methods: Initially, two new indexes for identifying difficult laryngoscopy are proposed, and their efficacy for predicting difficult laryngoscopy is compared to that of two conventional indexes. Second, a hybrid adaptive architecture with convolutional layers, spatial extraction, and a vision transformer is proposed for predicting difficult laryngoscopy. The proposed adaptive hybrid architecture is then optimized by determining the optimal location for extracting spatial information. Results: The test accuracy of four indexes using simple model is 0.8320. The test accuracy of optimized hybrid architecture using four indexes is 0.8482. Conclusion: The newly proposed two indexes, the angle between the lower margins of the second and sixth cervical spines and the vertical direction, are validated to be effective for recognizing difficult laryngoscopy. In addition, the optimized hybrid architecture employing four indexes demonstrates improved efficacy in detecting difficult laryngoscopy. Trial registration: Ethics permission for this research was obtained from the Medical Scientific Research Ethics Committee of Peking University Third Hospital (IRB00006761-2015021) on 30 March 2015. A well-informed agreement has been received from all participants. Patients were enrolled in this research at the Chinese Clinical Trial Registry (http://www.chictr.org.cn, identifier: ChiCTR-ROC-16008598) on 6 June 2016. [ABSTRACT FROM AUTHOR]

Purpose: As common clinical screening tests cannot effectively predict a difficult airway, and unanticipated difficult laryngoscopy remains a challenge for physicians. We herein used ultrasound to develop some point-of-care predictors for difficult laryngoscopy. Methods: This prospective observational study included 502 patients who underwent laryngoscopy and a detailed sonographic assessment. Patients under 18 years old, or with maxillofacial deformities or fractures, limited mouth opening, limited neck movement or history of neck surgery were excluded from the study. Laryngoscopic views of all patients were scored and grouping using the modified Cormack-Lehane (CL) scoring system. The measurements acquired comprised tongue width, the longitudinal cross-sectional area of the tongue, tongue volume, the mandible-hyoid bone distance, the hyoid bone-glottis distance, the mandible-hyoid bone-glottis angle, the skin-thyrohyoid membrane distance, the glottis-superior edge of the thyroid cartilage distance (DGTC), the skin-hyoid bone distance, and the epiglottis midway-skin distance. ANOVA and Chi-square were used to compare differences between groups. Logistic regression was used to identify risk factors for difficult laryngoscopy and it was visualized by receiver operating characteristic curves and nomogram. R version 3.6.3 and SPSS version 26.0 were used for statistical analyses. Results: Difficult laryngoscopy was indicated in 49 patients (CL grade Ⅲ – Ⅳ) and easy laryngoscopy in 453 patients (CL grade Ⅰ – Ⅱ). The ultrasound-measured mandible-hyoid bone-glottis angle and DGTC significantly differed between the 2 groups (p

Objective:Though airway ultrasonography (USG) is used to assess difficult laryngoscopy (DL), there is still ambiguity about approach followed and parameters assessed. There is need of a simple, stepwise sonographic assessment with clearly defined parameters for DL prediction. The primary objective of this study was to find diagnostic accuracy of sonographic parameters measured by a stepwise Airway-USG in DL prediction (DLP).Methods:This prospective, observational cohort study was done in 217 elective surgical adult patients administered general anaesthesia with tracheal intubation using conventional laryngoscopy from 1st May 2019 to 31st July 2020, after ethical approval. A sagittal Airway-USG was done using 2-6 Hz transducer in three steps specifying probe placement and head position. Demographic, clinical and Airway-USG measurements were noted. Correlation of the clinical/sonographic parameters was made with Cormack-Lehane score on DL. After receiver operating characteristic curve plotting, the sensitivity, specificity, positive predictive value, negative predictive value (NPV) of DL was calculated for each parameter using open-epi software.Results:DL was observed in 19/217 patients. Airway-USG parameters of skin to epiglottis distance >2.45 cm, hyomental distance with head extension 3.93 cm and maximum skin to tongue distance >5.45 cm were statistically significant in predicting DL. DLP score with presence of >3 positive parameters showed 98% specificity, 98% NPV and 96% diagnostic accuracy to predict DL.Conclusion:DLP score derived from Airway-USG may be used as a screening and diagnostic tool for DL.

Abstract Background Sternomental displacement (SMDD) is a surrogate indicator for cervical spine (C-spine) mobility. SMDD revealed good potential to predict difficult airway, but its validity in obese patients is not evident. Therefore, this study assessed the performance of SMDD with neck circumference (NC) in predicting difficult airway in obese surgical patients. The study involved 135 adult patients with body mass index (BMI) ≥ 35 kg/m2 scheduled for elective surgeries under general anesthesia with endotracheal tubes (ETT) inserted using Macintosh laryngoscopes. The airway was assessed using SMDD, NC, and modified Mallampati test (MMT). Difficult laryngoscopy view (DLV) was defined as Cormack–Lehane (C-L) grade ≥ 3. The accuracy of the SMDD in predicting DLV was set as the primary endpoint, while the accuracy of the SMDD compared to that of NC, MMT, and NC/SMDD ratio in predicting difficult airway was set as the secondary endpoint. Results The DLV cases were 28 of 135 (20.7%), with a mean BMI of 41.1 ± 3.3 kg/m2. SMDD 43 cm could predict DLV with an area under the receiver operating characteristic curve (AUROC) of 0.97 and 0.83 respectively. SMDD and NC had a good negative correlation (r = − 0.6; 95% CI = 0.7 to 0.4; p = 0.0001). The NC/SMDD ratio had the best prediction for DLV (AUROC of 0.98 at a cut-off value > 7.8). Conclusions In obese surgical patients, SMDD and NC/SMDD ratios are excellent predictors for DLV when the cut-off values are 7.8, respectively. Trial registration ClinicalTrials.gov, NCT04524546. Registered in August 2020.

Abstract Background Compared to other intravenous anesthetics, availability of a specific antagonist flumazenil is a clear advantage of remimazolam. We report a patient who could be rapidly woken up when laryngoscopy and tracheal intubation were unexpectedly difficult. Case presentation A 62-year-old man was scheduled to have resection of a small gingival tumor. Preoperative airway examination was unremarkable except for an omega-shaped epiglottis. Anesthesia was induced with remifentanil/remimazolam infusion and rocuronium. A small omega-shaped edematous epiglottis precluded identification of glottis. Consciousness and spontaneous ventilation were rapidly restored after administration of flumazenil and sugammadex. Tracheostomy was done under local anesthesia while the patient breathed spontaneously. Conclusions Remimazolam can be a reasonable induction agent when there are concerns regarding airway management. Avoiding repeated airway manipulations is extremely important to prevent deterioration into a “cannot intubate, cannot ventilate (CICV)” emergency.

BackgroundOver the last few years, ultrasonography has been introduced as the fifth pillar to patient’s bedside physical examination. Clinical assessments aim to screen and look for airway difficulties to predict difficult intubations, but none have demonstrated a significant predictive capacity. Recent systematic reviews have established a correlation between ultrasound imaging and difficult direct laryngoscopy. The primary objective of this study was to determine whether the utilization of ultrasonography to examine the upper airway could accurately predict difficult direct laryngoscopy.MethodsThis is a prospective observational study including 102 adult patients that required general anesthesia for elective surgery. Preoperatively, clinical airway assessments were performed. Data such as Mallampati-Samsoon grade (MS), upper lip bite test (ULBT), thyromental (TMD) and sternomental distance (SMD), cervical circumference (CC) and the Arné risk index were collected. Ultrasound evaluation was taken at five different levels in two planes, parasagittal and transverse. Therefore, the following measurements were registered: distance from skin to hyoid bone (DSHB), distance from skin to thyrohyoid membrane (DSTHM), distance from skin to epiglottis (DSE), distance from skin to thyroid cartilage (DSTC) and distance from hyoid bone and thyroid cartilage (DHBTC). Patients were divided into two groups based on the difficulty to perform direct laryngoscopy, according to Cormack-Lehane (C-L) classification. Grades I and II were classified as easy laryngoscopy and grades III or IV as difficult. Logistic regression models and the Receiver Operating Characteristic (ROC) curve was employed to determine the diagnostic precision of ultrasound measurements to distinguish difficult laryngoscopy (DL).ResultsThe following risk score for DL was obtained, DSTHM ≥ 1.60 cm (2 points), DSTC ≥ 0.78 cm (3 points) and gender (2 points for males). The score can range from 0 to 7 points, and showed and AUC (95% CI) of 0.84 (0.74–0.95). A score of 5 points or higher indicates a 34-fold increase in the risk of finding DL (p = 0.0010), sensitivity of 91.67, specificity of 75.56, positive predictive value of 33.33, and negative predictive value of 98.55.ConclusionThe use of ultrasonography combined with classic clinical screening tests are useful tools to predict difficult direct laryngoscopy.

Background: Difficult airway remains a great challenge in patients with atlantoaxial dislocation (AAD). Preoperative evaluation and reliable prediction are required to facilitate the airway management. We aimed to screen out reliable radiological indicators for prediction of difficult laryngoscopy in patients with AAD. Methods: A retrospective nested case-control study within a single center longitudinal AAD cohort was conducted to investigate the radiological indicators. All the patients with difficult laryngoscopy from 2010 to 2021 were enrolled as the difficult laryngoscopy group. Others in the cohort without difficult laryngoscopy were randomly selected as the non-difficult laryngoscopy group by individually matching with the same gender, same surgery year, and similar age (±5 years) at a ratio of 6:1. Radiological data on preoperative lateral X-ray images between the two groups were compared. Bivariate logistic regression model was applied to screen out the independent predictive indicators and calculate the odds ratios of indicators associated with difficult laryngoscopy. Receiver operating characteristic curve and area under the curve (AUC) were used to describe the discrimination ability of indicators. Results: A total of 154 patients were finally analyzed in this study. Twenty-two patients with difficult laryngoscopy and matched with 132 controls. Four radiological parameters showed significant difference between the two groups. Among which, ΔC1C2D (the difference of the distance between atlas and axis in the neutral and extension position), owned the largest AUC. Conclusions: ΔC1C2D could be a valuable radiologic predictor for difficult laryngoscopy in patients with AAD.

As common clinical screening tests cannot effectively predict a difficult airway, and unanticipated difficult laryngoscopy remains a challenge for physicians. We herein used ultrasound to develop some point-of-care predictors for difficult laryngoscopy. This prospective observational study included 502 patients who underwent laryngoscopy and a detailed sonographic assessment. Patients under 18 years old, or with maxillofacial deformities or fractures, limited mouth opening, limited neck movement or history of neck surgery were excluded from the study. Laryngoscopic views of all patients were scored and grouping using the modified Cormack-Lehane (CL) scoring system. The measurements acquired comprised tongue width, the longitudinal cross-sectional area of the tongue, tongue volume, the mandible-hyoid bone distance, the hyoid bone-glottis distance, the mandible-hyoid bone-glottis angle, the skin-thyrohyoid membrane distance, the glottis-superior edge of the thyroid cartilage distance (DGTC), the skin-hyoid bone distance, and the epiglottis midway-skin distance. ANOVA and Chi-square were used to compare differences between groups. Logistic regression was used to identify risk factors for difficult laryngoscopy and it was visualized by receiver operating characteristic curves and nomogram. R version 3.6.3 and SPSS version 26.0 were used for statistical analyses. Difficult laryngoscopy was indicated in 49 patients (CL grade Ⅲ – Ⅳ) and easy laryngoscopy in 453 patients (CL grade Ⅰ – Ⅱ). The ultrasound-measured mandible-hyoid bone-glottis angle and DGTC significantly differed between the 2 groups (p < 0.001). Difficult laryngoscopy was predicted by an area under the curve (AUC) of 0.930 with a threshold mandible-hyoid bone-glottis angle of 125.5° and by an AUC of 0.722 with a threshold DGTC of 1.22 cm. The longitudinal cross-sectional area of the tongue, tongue width, tongue volume, the mandible-hyoid distance, and the hyoid-glottis distance did not significantly differ between the groups. Difficult laryngoscopy may be anticipated in patients in whom the mandible-hyoid bone-glottis angle is smaller than 125.5° or DGTC is larger than 1.22 cm. [ABSTRACT FROM AUTHOR]

Introduction: There is an increasing interest in using airway ultrasound to predict difficult intubation. Studies to date have excluded pregnant women in reporting airway measurements. We performed this study to compare the mean distance from skin to epiglottis in parturients to that reported in previously published studies. We also assessed the correlation of mean distance from skin to epiglottis with other elements of the airway examination. Methods: A total of 100 parturients were recruited from a tertiary hospital's labor and delivery floor. Standard physical examination parameters were recorded in addition to the mean distance from skin to epiglottis for all subjects. The ratio of height-to-thyromental distance was used to classify airways as potentially favorable or unfavorable. Results: The average mean distance from skin to epiglottis in parturients was 19.9 ± 3.3 mm and followed a normal distribution. The mean distance from skin to epiglottis was moderately correlated with height and body mass index. There was no difference in mean distance from skin to epiglottis between subjects with favorable versus unfavorable airways as classified by ratio of height-to-thyromental distance. Conclusion: The typical mean distance from skin to epiglottis in parturients falls between previously published values in mixed populations. Previously published cut-off values using airway ultrasound to predict difficult intubation are not likely to apply to parturients. [ABSTRACT FROM AUTHOR]

Objective: Though airway ultrasonography (USG) is used to assess difficult laryngoscopy (DL), there is still ambiguity about approach followed and parameters assessed. There is need of a simple, stepwise sonographic assessment with clearly defined parameters for DL prediction. The primary objective of this study was to find diagnostic accuracy of sonographic parameters measured by a stepwise Airway- USG in DL prediction (DLP). Methods: This prospective, observational cohort study was done in 217 elective surgical adult patients administered general anaesthesia with tracheal intubation using conventional laryngoscopy from 1st May 2019 to 31st July 2020, after ethical approval. A sagittal Airway- USG was done using 2-6 Hz transducer in three steps specifying probe placement and head position. Demographic, clinical and Airway- USG measurements were noted. Correlation of the clinical/sonographic parameters was made with Cormack-Lehane score on DL. After receiver operating characteristic curve plotting, the sensitivity, specificity, positive predictive value, negative predictive value (NPV) of DL was calculated for each parameter using open-epi software. Results: DL was observed in 19/217 patients. Airway-USG parameters of skin to epiglottis distance >2.45 cm, hyomental distance with head extension <5.13 cm, head neutral <4.5 cm, their ratio <1.18, maximum tongue thickness >3.93 cm and maximum skin to tongue distance >5.45 cm were statistically significant in predicting DL. DLP score with presence of >3 positive parameters showed 98% specificity, 98% NPV and 96% diagnostic accuracy to predict DL. Conclusion: DLP score derived from Airway-USG may be used as a screening and diagnostic tool for DL. [ABSTRACT FROM AUTHOR]

Background: Unanticipated difficult intubation poses a challenge in routine practice for anaesthesiologists. A preoperative airway evaluation helps in the identification of a difficult airway. Airway assessment with ultrasound is a modality recently being used to predict difficult airway. In this study we evaluate ultrasonography parameters with conventional clinical parameters for predicting difficult airway in adults undergoing elective surgeries. Methods: This cross sectional randomised clinical trial analyses ASA class 1 and 2 adults requiring endotracheal intubation for surgeries under general anaesthesia were enrolled following which Modified Mallampatti score and thyromental distance as well as ultrasound distance to epiglottis (DSE) and distance to hyoid bone (DSHB) were measured and based on Cormack Lehane grading they were categorised into easy and difficult airway groups. Results: DSE had the highest sensitivity of 90.48% whereas Modified Mallampatti grading had least sensitivity of 66.67%. Conclusion: The results of this study showed that ultrasonographic measurements at the thyrohyoid and hyoid level have higher sensitivity and specificity than the clinical parameters for airway assessment.

Background: Sternomental displacement (SMDD) is a surrogate indicator for cervical spine (C-spine) mobility. SMDD revealed good potential to predict difficult airway, but its validity in obese patients is not evident. Therefore, this study assessed the performance of SMDD with neck circumference (NC) in predicting difficult airway in obese surgical patients. The study involved 135 adult patients with body mass index (BMI) ≥ 35 kg/m2 scheduled for elective surgeries under general anesthesia with endotracheal tubes (ETT) inserted using Macintosh laryngoscopes. The airway was assessed using SMDD, NC, and modified Mallampati test (MMT). Difficult laryngoscopy view (DLV) was defined as Cormack–Lehane (C-L) grade ≥ 3. The accuracy of the SMDD in predicting DLV was set as the primary endpoint, while the accuracy of the SMDD compared to that of NC, MMT, and NC/SMDD ratio in predicting difficult airway was set as the secondary endpoint. Results: The DLV cases were 28 of 135 (20.7%), with a mean BMI of 41.1 ± 3.3 kg/m2. SMDD < 5cm and NC > 43 cm could predict DLV with an area under the receiver operating characteristic curve (AUROC) of 0.97 and 0.83 respectively. SMDD and NC had a good negative correlation (r = − 0.6; 95% CI = 0.7 to 0.4; p = 0.0001). The NC/SMDD ratio had the best prediction for DLV (AUROC of 0.98 at a cut-off value > 7.8). Conclusions: In obese surgical patients, SMDD and NC/SMDD ratios are excellent predictors for DLV when the cut-off values are < 5cm and > 7.8, respectively. Trial registration: ClinicalTrials.gov, NCT04524546. Registered in August 2020. [ABSTRACT FROM AUTHOR]

The difficulty in achieving airway patency varies with anatomic and acquired individual patient factors. Thus performing an airway assessment preoperatively in identifying a patient for a potentially difficult intubation is of pivotal importance for the anaesthesiologist. Initially single preoperative airway assessment tests like mouth opening or Inter incisor gap (IIG), Head and neck movement (HNM), Modified mallampatti test (MMT), were used to predict difficult airway. A standard general anesthesia protocol was followed for all cases. All patients received premedication, inj midazolam 0.02 mg/kg, inj glycopyrrolate 0.01mg/kg and inj fentanyl 2 µg/kg intravenously, after attaching standard monitors. After preoxygenation with 100% O2 in each patient, anesthesia was induced with 5-7mg/kg of thiopentone sodium and 0.9 mg/kg of Rocuronium given intravenously to facilitate tracheal intubation after ensuring mask ventilation. Out of 212(81.53%) subjects with RHTMD less than 23.5cm, 5(1.92%) belonged to difficult intubation group. RHTMD more than 23.5cm was there in 48(18.4%) subjects and among them 34(13.07%) had difficult intubation and this is statistically significant with p value 0.001. [ABSTRACT FROM AUTHOR]

Background: Compared to other intravenous anesthetics, availability of a specific antagonist flumazenil is a clear advantage of remimazolam. We report a patient who could be rapidly woken up when laryngoscopy and tracheal intubation were unexpectedly difficult. Case presentation: A 62-year-old man was scheduled to have resection of a small gingival tumor. Preoperative airway examination was unremarkable except for an omega-shaped epiglottis. Anesthesia was induced with remifentanil/remimazolam infusion and rocuronium. A small omega-shaped edematous epiglottis precluded identification of glottis. Consciousness and spontaneous ventilation were rapidly restored after administration of flumazenil and sugammadex. Tracheostomy was done under local anesthesia while the patient breathed spontaneously. Conclusions: Remimazolam can be a reasonable induction agent when there are concerns regarding airway management. Avoiding repeated airway manipulations is extremely important to prevent deterioration into a "cannot intubate, cannot ventilate (CICV)" emergency. [ABSTRACT FROM AUTHOR]

Objectives: The distance from skin to the hyoid bone (DSHB) and skin to the anterior commissure of vocal cords (DSAC) are reliable parameters for pre‐operative airway ultrasound assessment in awake patients and can be assessed in comatose patients. This study aimed to inspect its feasibility and accuracy in predicting difficult laryngoscopy for comatose patients. Methods: A prospective cohort study included patients with a Glasgow Coma Scale (GCS) of ≤8 who underwent emergency tracheal intubation between November 2019 and August 2020. The outcome was difficult laryngoscopy and classified according to the Cormack–Lehane grading. Results: A total of 151 patients were included in the study. Fifty‐two (34.4%) patients were categorized as having difficult laryngoscopy. The DSHB add DSAC (hereinafter referred to as the "DSBAC") was superior to either parameter alone in the predictive performance, and the optimal cut‐off value was 1.90. To optimize the predictive value, DSBAC (adjusted odds ratio [OR]: 7.76; 95% confidence interval [CI]: 2.88–20.94; P <.001), GCS (adjusted OR: 1.39; 95% CI: 3.93–26.28; P =.039), mandibular retraction (adjusted OR: 8.20; 95% CI: 1.92–35.09; P =.005) and edentulous (adjusted OR: 4.23; 95% CI: 1.40–12.80; P =.011) were included in a multivariable model and constructed a nomogram. Discrimination and calibration statistics were satisfactory, with C‐index above 0.80 from both model development and internal validation. Conclusions: Ultrasound‐derived factor, DSBAC, can be easily assessed and help predict difficult laryngoscopy among comatose patients. A simple nomogram including only four clinical items exhibited excellent discrimination performance and was useful when comatose patients underwent emergency tracheal intubation. [ABSTRACT FROM AUTHOR]

Background Airway assessment before anaesthesia in the elderly is crucial. The delay in endotracheal intubation in this age group can lead to fatal consequences. This study aimed to evaluate the validity of sternomental displacement (SMDD) as a predictor of difficult airway in the elderly and to compare it with the thyromental height test (TMHT).Methods This study included 150 patients aged > 65 years old, ASA i–iii, who were scheduled for elective surgeries under general anaesthesia with endotracheal intubation using conventional laryngoscopy. Cormack–lehane grades iii and iv were assigned as difficult laryngoscopy (DL). Difficult intubation (DI) was defined as insertion of endotracheal tube required more than two attempts or 10 minutes. The primary outcome was the AUROC curve for the SMDD as a predictor of difficult laryngoscopy.Results 14% of our patients showed DL, while 4.7% had DI. SMDD was a good predictor for DL with 0.692 AUC (95% ci: 0.611 − 0.765) at a cut-off value of ≤35 mm, with 71.43% sensitivity, 59.69% specificity, 22.4% PPV and 92.8% NPV. TMHT showed good prediction for DL with 0.794 AUC (95% ci: 0.721–0.856) at a cut-off value of ≤ 49.5 mm. For predicting DI, SMDD showed AUROC (95% ci): 0.814 (0.743–0.873) at a cut-off value ≤35 mm and TMHT had AUROC (95% ci): 0.719 (0.640–0.790) at a cut-off value ≤ 49.5 mm.Conclusion SMDD and TMHT are good objective predictors for DL and di in elderly surgical patients.

Abstract Background Maintaining patent airways is vital in pediatric anesthetic management. Failure to manage and anticipate difficult laryngoscopy (DL) preoperatively is the leading cause of morbidity and mortality. Data on the predictive values of screening parameters in predicting DL are limited in children. Therefore, this study aimed to assess the predictive value of the modified Mallampati test (MMT), upper lip bite test (ULBT), thyromental distance (TMD), and ratio of height to thyromental distance (RHTMD) in predicting DL in children aged 5–12 years at selected Addis Ababa governmental hospitals in Ethiopia. Methods A multicenter cross-sectional study was conducted on 141 elective pediatric surgical patients aged 5 to 12 years selected using a systematic random sampling technique at three governmental hospitals from December 1, 2021, to April 30, 2022. The collected data were entered and analysed by SPSS version 26. Chi-square and Fisher’s exact tests were used to compare categorical variables. The receiver operating characteristic curve analysis was used to compare the accuracy of MMT, ULBT, TMD, and RHTMD against DL. A P value

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Purpose: The aim of this study is to examine the relationship between the measurement of anterior neck soft tissue thickness and the difficult laryngoscopy in which cesarean section under general anesthesia. Our secondary aim is to determine the efficacy of the other predictive tests and post-induction indicators to detect difficult laryngoscopy in pregnant women. Materials and Methods: One hundred fiftytwo pregnant women (18-45 years old, American Society of Anesthesiologists Physical Status Class II) were included. According to Cormack and Lehane’s scale (Grade I-II: easy laryngoscopy, Grade III-IV: difficult laryngoscopy) patients were divided into two groups. The distance from the skin to the anterior aspect of the trachea was measured at five different levels (hyoid bone, thyrohyoid membrane, vocal cords, thyroid isthmus, and suprasternal notch) with ultrasound. In addition, the other predictive tests and post-induction indicators for predetermining difficult laryngoscopy were recorded. Results: There was no significant difference in the anterior neck soft tissue ultrasound measurements between the groups. Having limited mouth opening (4.80±0.51cm), buck teeth (20%), high Wilson's Risk Score (0.73±0.82), large neck circumference (41.40±2.96cm), inability to bite the upper lip (43%), and high Modified Mallampati Score (33%) were seen statistically significantly more common in the difficult laryngoscopy group. In addition, ‘‘Backward, Upward, Rightward Pressure’’ maneuver, use of gum elastic bougie, high Intubation Difficulty Score, and >2 intubation attempts were more frequently found in the difficult laryngoscopy group. Conclusion: Measuring the anterior neck soft tissue with ultrasound is ineffective for determining difficult laryngoscopy in pregnant women. On the other hand, Mallampati Score, upper lip bite test, mouth opening, neck circumference, buck teeth, and Wilson's Risk Score can be helpful in the determination of difficult laryngoscopy in pregnancies.

Sorravit Savatmongkorngul, Panrikan Pitakwong, Pungkava Sricharoen, Chaiyaporn Yuksen, Chetsadakon Jenpanitpong, Sorawich Watcharakitpaisan Department of Emergency Medicine, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, ThailandCorrespondence: Chaiyaporn Yuksen, Department of Emergency Medicine, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, 10400, Thailand, Email chaipool0634@hotmail.comObjective: Difficult laryngoscopy is associated with difficult intubation, an increasing number of endotracheal intubation attempts, and adverse events. Clinical prediction of difficult airways in an emergency setting was limited in sensitivity and specificity. This study developed a new model for predicting difficult laryngoscopy in the emergency department.Methods: This retrospective cohort study was conducted using an exploratory model at the Emergency Medicine of Ramathibodi Hospital. The study was conducted from June 2018 to July 2020. The eligibility criteria were an age of ≥ 15 years who undergo intubation in the emergency department. Difficult laryngoscopy was defined as a Cormack–Lehane grade 3 and above. The predictive model and score were developed by multivariable logistic regression analysis.Results: A total of 617 patients met the eligibility criteria; 83 (13.45%) had difficult laryngoscopy. Five independent factors were predictive of difficult laryngoscopy. Significant factors were M: limited mouth opening, O: presence of obstructed airway, N: poor neck mobility, T: large tongue, and H: short hypo-mental distance. The difficult laryngoscopy score had an accuracy of 89%. A score of > 4 increased the likelihood ratio of difficult laryngoscopy by 7.62 times.Conclusion: The MONTH Difficult Laryngoscopy Score of > 4 was associated with difficult laryngoscopy.Keywords: difficult laryngoscopy, prediction score, emergency department intubation

Summary: Unanticipated difficult laryngoscopy is associated with serious airway‐related complications. We aimed to develop and test a convolutional neural network‐based deep‐learning model that uses lateral cervical spine radiographs to predict Cormack–Lehane grade 3 or 4 direct laryngoscopy views of the glottis. We analysed the radiographs of 5939 thyroid surgery patients at our hospital, 253 (4%) of whom had grade 3 or 4 glottic views. We used 10 randomly sampled datasets to train a model. We compared the new model with six similar models (VGG, ResNet, Xception, ResNext, DenseNet and SENet). The Brier score (95%CI) of the new model, 0.023 (0.021–0.025), was lower ('better') than the other models: VGG, 0.034 (0.034–0.035); ResNet, 0.033 (0.033–0.035); Xception, 0.032 (0.031–0.033); ResNext, 0.033 (0.032–0.033); DenseNet, 0.030 (0.029–0.032); SENet, 0.031 (0.029–0.032), all p < 0.001. We calculated mean (95%CI) of the new model for: R2, 0.428 (0.388–0.468); mean squared error, 0.023 (0.021–0.025); mean absolute error, 0.048 (0.046–0.049); balanced accuracy, 0.713 (0.684–0.742); and area under the receiver operating characteristic curve, 0.965 (0.962–0.969). Radiographic features around the hyoid bone, pharynx and cervical spine were associated with grade 3 and 4 glottic views. [ABSTRACT FROM AUTHOR]

Background: In morbidly obese patients, airway management is challenging since the incidence of difficult intubation is three times than those with a BMI within the healthy range. Standard preoperative airway evaluation may help to predict difficult laryngoscopy. Recent studies have used ultrasonography-measured distance from skin to epiglottis and pretracheal soft tissue at the level of vocal cords, and cut-off points of 27.5 mm and 28 mm respectively have been proposed to predict difficult laryngoscopy. The purpose of this study is to evaluate ultrasonography-measured distance from skin to epiglottis for predicting difficult laryngoscopy in morbidly obese Thai patients. Methods: This prospective observational study was approved by the Ethics Committee of the Faculty of Medicine, Prince of Songkla University. Data were collected from January 2018 to August 2020. Eighty-eight morbidly obese patients (BMI ≥ 35 kg/m2) requiring general anesthesia with endotracheal intubation for elective surgery were enrolled in the Songklanagarind Hospital. Preoperatively, anesthesiologists or nurse anesthetists who were not involved with intubation evaluated and recorded measurements (body mass index, neck circumference, inter incisor distance, sternomental distance, thyromental distance, modified Mallampati scoring, upper lip bite test, and distance from skin to epiglottis by ultrasound. The laryngoscopic view was graded on the Cormack and Lehane scale. Results: Mean BMI of the eighty-eight patients was 45.3 ± 7.6 kg/m2. The incidence of difficult laryngoscopy was 14.8%. Univariate analysis for difficult laryngoscopy indicated differences in thyromental distance, sternomental distance and the distance from skin to epiglottis by ultrasonography. The median (IQR) of thyromental distance in difficult laryngoscopy was 6.5 (6.3, 8.0) cm compared with 7.5(7.0, 8.0) cm in easy laryngoscopy (p-value 0.03). The median (IQR) of sternomental distance in difficult laryngoscopy was 16.8 (15.2, 18.0) cm compared with 16.0 (14.5, 16.0) cm in easy laryngoscopy (p-value 0.05). The mean distance from skin to epiglottis was 12.2 ± 3.3 mm Mean of distance from skin to epiglottis in difficult laryngoscopy was 12.5 ± 3.3 mm compared with 10.6 ± 2.9 mm in easy laryngoscopy (p-value 0.05). Multivariate logistic regression indicated the following factors associated with difficult laryngoscopy: age more than 43 years (A), thyromental distance more than 68 mm(B) and the distance from skin to epiglottis more than 13 mm(C). The scores to predict difficult laryngoscopy was calculated as 8A + 7B + 6C based on the data from our study. One point is given for A if age was more than 43 years old, 1 point is given for B if thyromental distance was less than 6.8 cm and 1 point is given for C if the distance from skin to epiglottis by ultrasonography was more than 13.0 cm. The maximum predicting score is 21, which indicates a probability of difficult laryngoscopy among our patients of 36.36%, odds 0.57, likelihood ratio 3.29 and area under the ROC curve of 0.77, indicative of a good predictive score. Conclusions: Age, thyromental distance and ultrasonography for the distance from skin to epiglottis can predict difficult laryngoscopy among obese Thai patients. The predictive score indicates the probability of difficult laryngoscopy. [ABSTRACT FROM AUTHOR]

Thyromental height test (TMHT) revealed good potential to predict difficult airway but with variable cut-off values. This study aimed to assess the validity of TMHT either as a sole test or within multivariable models for predicting difficult airway. The study included 612 patients aged ≥18 years who were scheduled for elective surgeries under general anaesthesia with an endotracheal tube. Airway was assessed with TMHT, Thyromental distance (TMD), Sternomental distance (SMD), inter-incisor distance (IID), and Modified Mallampati test (MMT). The difficult laryngoscopy (DL) was defined as Cormack–Lehane (C-L) grade > 2. The primary outcome was the validity of TMHT as a predictor for DL. Cases with DL were 56 (9.2%) patients, while cases with difficult intubation (DI) were 7 (1.1%). The TMHT was significantly shorter in cases with DL compared to easy laryngoscopy (45.82 ± 8.21 versus 56.93 ± 8.83 mm, respectively) and in cases with DI compared to easy intubation (42 ± 7.19 versus 56.07 ± 9.24 mm respectively). TMHT was a good predictor for both DL and DI at a cut-off value of ≤ 48 mm with an AUROC (Area Under the Receiver Operating Characteristic) curve of 0.82 (95% CI: 0.79 to 0.85) and 0.89 (95% CI: 0.82 to 0.92), respectively. The logistic regression analysis incorporated the TMHT within two multivariable predictive models for DL and DI with better predictive ability. In adult surgical patients, TMHT is a good objective predictor for DL and DI. The predictive ability increased when incorporated into two multivariable models. ClinicalTrials.gov, ID: NCT04264338 in February 2020. [ABSTRACT FROM AUTHOR]

Airway assessment before anaesthesia in the elderly is crucial. The delay in endotracheal intubation in this age group can lead to fatal consequences. This study aimed to evaluate the validity of sternomental displacement (SMDD) as a predictor of difficult airway in the elderly and to compare it with the thyromental height test (TMHT). This study included 150 patients aged > 65 years old, ASA i–iii, who were scheduled for elective surgeries under general anaesthesia with endotracheal intubation using conventional laryngoscopy. Cormack–lehane grades iii and iv were assigned as difficult laryngoscopy (DL). Difficult intubation (DI) was defined as insertion of endotracheal tube required more than two attempts or 10 minutes. The primary outcome was the AUROC curve for the SMDD as a predictor of difficult laryngoscopy. 14% of our patients showed DL, while 4.7% had DI. SMDD was a good predictor for DL with 0.692 AUC (95% ci: 0.611 − 0.765) at a cut-off value of ≤35 mm, with 71.43% sensitivity, 59.69% specificity, 22.4% PPV and 92.8% NPV. TMHT showed good prediction for DL with 0.794 AUC (95% ci: 0.721–0.856) at a cut-off value of ≤ 49.5 mm. For predicting DI, SMDD showed AUROC (95% ci): 0.814 (0.743–0.873) at a cut-off value ≤35 mm and TMHT had AUROC (95% ci): 0.719 (0.640–0.790) at a cut-off value ≤ 49.5 mm. SMDD and TMHT are good objective predictors for DL and di in elderly surgical patients. [ABSTRACT FROM AUTHOR]

Abstract Background In morbidly obese patients, airway management is challenging since the incidence of difficult intubation is three times than those with a BMI within the healthy range. Standard preoperative airway evaluation may help to predict difficult laryngoscopy. Recent studies have used ultrasonography-measured distance from skin to epiglottis and pretracheal soft tissue at the level of vocal cords, and cut-off points of 27.5 mm and 28 mm respectively have been proposed to predict difficult laryngoscopy. The purpose of this study is to evaluate ultrasonography-measured distance from skin to epiglottis for predicting difficult laryngoscopy in morbidly obese Thai patients. Methods This prospective observational study was approved by the Ethics Committee of the Faculty of Medicine, Prince of Songkla University. Data were collected from January 2018 to August 2020. Eighty-eight morbidly obese patients (BMI ≥ 35 kg/m2) requiring general anesthesia with endotracheal intubation for elective surgery were enrolled in the Songklanagarind Hospital. Preoperatively, anesthesiologists or nurse anesthetists who were not involved with intubation evaluated and recorded measurements (body mass index, neck circumference, inter incisor distance, sternomental distance, thyromental distance, modified Mallampati scoring, upper lip bite test, and distance from skin to epiglottis by ultrasound. The laryngoscopic view was graded on the Cormack and Lehane scale. Results Mean BMI of the eighty-eight patients was 45.3 ± 7.6 kg/m2. The incidence of difficult laryngoscopy was 14.8%. Univariate analysis for difficult laryngoscopy indicated differences in thyromental distance, sternomental distance and the distance from skin to epiglottis by ultrasonography. The median (IQR) of thyromental distance in difficult laryngoscopy was 6.5 (6.3, 8.0) cm compared with 7.5(7.0, 8.0) cm in easy laryngoscopy (p-value 0.03). The median (IQR) of sternomental distance in difficult laryngoscopy was 16.8 (15.2, 18.0) cm compared with 16.0 (14.5, 16.0) cm in easy laryngoscopy (p-value 0.05). The mean distance from skin to epiglottis was 12.2 ± 3.3 mm Mean of distance from skin to epiglottis in difficult laryngoscopy was 12.5 ± 3.3 mm compared with 10.6 ± 2.9 mm in easy laryngoscopy (p-value 0.05). Multivariate logistic regression indicated the following factors associated with difficult laryngoscopy: age more than 43 years (A), thyromental distance more than 68 mm(B) and the distance from skin to epiglottis more than 13 mm(C). The scores to predict difficult laryngoscopy was calculated as 8A + 7B + 6C based on the data from our study. One point is given for A if age was more than 43 years old, 1 point is given for B if thyromental distance was less than 6.8 cm and 1 point is given for C if the distance from skin to epiglottis by ultrasonography was more than 13.0 cm. The maximum predicting score is 21, which indicates a probability of difficult laryngoscopy among our patients of 36.36%, odds 0.57, likelihood ratio 3.29 and area under the ROC curve of 0.77, indicative of a good predictive score. Conclusions Age, thyromental distance and ultrasonography for the distance from skin to epiglottis can predict difficult laryngoscopy among obese Thai patients. The predictive score indicates the probability of difficult laryngoscopy.

Background: Maintaining patent airways is vital in pediatric anesthetic management. Failure to manage and anticipate difficult laryngoscopy (DL) preoperatively is the leading cause of morbidity and mortality. Data on the predictive values of screening parameters in predicting DL are limited in children. Therefore, this study aimed to assess the predictive value of the modified Mallampati test (MMT), upper lip bite test (ULBT), thyromental distance (TMD), and ratio of height to thyromental distance (RHTMD) in predicting DL in children aged 5–12 years at selected Addis Ababa governmental hospitals in Ethiopia. Methods: A multicenter cross-sectional study was conducted on 141 elective pediatric surgical patients aged 5 to 12 years selected using a systematic random sampling technique at three governmental hospitals from December 1, 2021, to April 30, 2022. The collected data were entered and analysed by SPSS version 26. Chi-square and Fisher's exact tests were used to compare categorical variables. The receiver operating characteristic curve analysis was used to compare the accuracy of MMT, ULBT, TMD, and RHTMD against DL. A P value < 0.05 was considered statistically significant. Results: The magnitude of DL was 15.6%. MMT has the highest sensitivity (86.4%), specificity (91.6%), and negative predictive value (NPV) (97.3%) compared to other tests. The ULBT also has a high sensitivity (72.7%) and specificity (84%) with comparable diagnostic accuracy (90.8%) with the MMT (P < 0.05). The sensitivity, specificity, positive predictive value (PPV), NPV, and accuracy of TMD were 63.6%, 95.8%, 73.7%, 93.4%, and 82.2%, respectively. The RHTMD has the lowest specificity (63.6%), PPV (22.5%), NPV (91.4%), and accuracy (56.7%) in predicting DL. Conclusion: The MMT and ULBT are good screening tests, followed by the TMD in predicting DL, while the RHTMD was the least accurate predictor. Because no single test has 100% predictive value, a combination of screening tests is advised in pediatrics for predicting DL. [ABSTRACT FROM AUTHOR]

Introduction and Objectives: The occurrence of a difficult airway during intubation is a critical event in anaesthesia. Despite the usefulness of clinical predictors, difficult intubation frequently arises unexpectedly. The aim of this study was to determine the utility of airway ultrasound in detecting these patients., Materials and Methods: This was a case-control study. The patients in the case group were identified from the registry of patients with reports of difficult laryngoscopy (Cormack III and IV). The controls were selected from among patients classed as Cormack I who underwent surgery under general anaesthesia. Fifty patients (25 cases and 25 controls) participated in the study. All patients underwent ultrasound to obtain 3 measurements: distance from the skin to the hyoid bone, distance from the skin to the epiglottis, and distance from the skin to the vocal cords., Results: A skin-to-hyoid bone distance greater than 9.8 mm (50% of the sample) generated an odds ratio of 5.46 (p = 0.005); a skin-to-epiglottis distance greater than 21.3 mm (50% of the sample) generated an odds ratio of 6.62 (p = 0.002). There was no significant difference in the skin-to-vocal cords distance., Conclusions: Ultrasound has proven to be a useful tool for predicting difficult laryngoscopy. Despite the low sensitivity of clinical predictors, they appear to improve the detection of patients with difficult laryngoscopy when integrated into predictive models alongside ultrasound values., (Copyright © 2024 The Authors. Publicado por Elsevier España, S.L.U. All rights reserved.)

Background As part of preoperative patient evaluations, it is customary to estimate the likelihood of difficulties during laryngoscopy and intubation. A diverse array of predictors is frequently employed by anesthesiologists to anticipate difficult laryngoscopy (DL); however, no single predictor has been established as the gold standard. In the present study, we compared routine preoperative ultrasound-guided airway examination and clinical airway examination in predicting DL in patients coming for elective surgery. Methodology The present study is a single-blinded observational study that spanned 12 months, beginning in March 2018 and concluding in February 2019. The study took place at Kovai Medical Center and Hospital (KMCH), which is a tertiary-care facility in Coimbatore, India. The data were obtained through face-to-face interviews, with a sample size of 135 research participants. The questionnaire contained comprehensive data regarding the patient's age, weight, gender, comorbidities, planned surgery, and preoperative assessment, which encompassed a detailed examination of the airway. The clinical airway examination comprised assessing mouth opening, performing the modified Mallampati test, measuring thyromental height (TMH) and thyromental distance (TMD), evaluating neck circumference, and observing neck extension. Ultrasound-guided airway examination was performed during the immediate pre-operative period, focusing on specific parameters such as the pre-epiglottic space, anterior neck soft tissue at the level of vocal cords, thyrohyoid membrane, suprasternal notch, hyoid bone (single parameter measured at different levels), hyo-mental ratio, and tongue volume (TV). Results Among the ultrasound parameters, TV (72.15 cm 3 ) is the best ultrasound parameter to predict DL (95% CI: 0.65 to 0.82), with a high sensitivity of 82% and specificity of 45.88%. Other parameters that are useful are anterior neck soft tissue at the level of the thyrohyoid membrane (0.67 cm), suprasternal notch (1.01 cm), and, lastly, pre-epiglottic space (0.57 cm). Among clinical parameters, modified Mallampati grade (grade 3 or more) is the best parameter to assess the airway clinically and predict DL, followed by neck circumference (>42 cm) and TMH (>5 cm). Based on the findings, we observed that both clinical and ultrasound parameters are comparable to predict DL. Conclusion We observed that routine clinical airway examination and ultrasound examination yielded comparable results in predicting DL. Therefore, the routine use of clinical airway examination still holds good in predicting DL., Competing Interests: Human subjects: Consent was obtained or waived by all participants in this study. Institutional Ethics Committee of KMCH Limited, Coimbatore issued approval EC/AP/566/10/2017. Animal subjects: All authors have confirmed that this study did not involve animal subjects or tissue. Conflicts of interest: In compliance with the ICMJE uniform disclosure form, all authors declare the following: Payment/services info: All authors have declared that no financial support was received from any organization for the submitted work. Financial relationships: All authors have declared that they have no financial relationships at present or within the previous three years with any organizations that might have an interest in the submitted work. Other relationships: All authors have declared that there are no other relationships or activities that could appear to have influenced the submitted work., (Copyright © 2024, Andrews et al.)

Introduction: We aim to compare the upper lip bite test with the modified Mallampati test as predictors of difficult laryngoscopy and/or difficult intubation among morbidly obese patients., Methods: A total of 500 morbidly obese patients (body mass index > 40 kg/m 2 ) undergoing general anaesthesia with tracheal intubation are included in this prospective single-blinded observational clinical study. The preoperative airway assessment is obtained by the modified Mallampati test and upper lip bite test. The difficulty of laryngoscopy is assessed by an experienced anaesthetist in patients adequately anaesthetised and fully relaxed. The view is classified according to Cormack and Lehane's classification. Modified Mallampati test III or IV and upper lip bite test III are considered positive tests. Difficult laryngoscopy is defined as Cormack and Lehane's classification III and IV, whereas difficult endotracheal intubation is defined as an intubation difficulty scale ⩾ 5., Results: The incidences of Cormack and Lehane's classification III and IV and intubation difficulty scale ⩾ 5 are 9.4% and 11.8% respectively. The specificity, positive predictive value and accuracy are higher with the upper lip bite test. The combination of the upper lip bite test and the modified Mallampati test improved these measures. The likelihood ratio + was significantly higher for the upper lip bite test (6.35 and 9.47) than for the modified Mallampati test (3.21 and 3.16)., Conclusion: The upper lip bite test is a test with high sensitivity, specificity, negative predictive value and accuracy making it a favourable test for identifying easy and difficult intubations and laryngoscopies in morbidly obese patients., Competing Interests: Declaration of conflicting interestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship and/or publication of this article.

Difficult laryngoscopy is associated with airway injury, and asphyxia. There are no guidelines or gold standards for detecting difficult laryngoscopy. There are many opinions on which predictors to use to detect difficult laryngoscopy exposure, and no comprehensively unified comparative analysis has been conducted. The efficacy and accuracy of deep learning (DL)-based models and machine learning (ML)-based models for predicting difficult laryngoscopy need to be evaluated and compared, under the circumstance that the flourishing of deep neural networks (DNN) has increasingly left ML less concentrated and uncreative. For the first time, the performance of difficult laryngoscopy prediction for a dataset of 671 patients, under single index and integrated multiple indicators was consistently verified under seven ML-based models and four DL-based approaches. The top dog was a simple traditional machine learning model, Naïve Bayes, outperforming DL-based models, the best test accuracy is 86.6%, the F1 score is 0.908, and the average precision score is 0.837. Three radiological variables of difficult laryngoscopy were all valuable separately and combinedly and the ranking was presented. There is no significant difference in performance among the three radiological indicators individually (83.06% vs. 83.20% vs. 83.33%) and comprehensively (83.74%), suggesting that anesthesiologists can flexibly choose appropriate measurement indicators according to the actual situation to predict difficult laryngoscopy. Adaptive spatial interaction was imposed to the model to boost the performance of difficult laryngoscopy prediction with preoperative cervical spine X-ray.

Abstract Background Airway management is one of the most important techniques in anesthesia practice and inappropriate airway management is related with airway injury, brain hypoxia, and even death. The patients with cervical spondylosis are often confronted with difficult laryngoscopy who are more prone to appear difficult airway, so it is important to figure out valuable predictors of difficult laryngoscopy in these patients. Methods We randomly enrolled 270 patients undergoing elective cervical spine surgery and analyzed the cervical mobility data in predicting difficult laryngoscopy. The preoperative X-ray radiological indicators were measured by an attending radiologist. Cormack-Lehane scales were assessed during intubation, and patients with a class III or IV view were assigned to the difficult laryngoscopy group. Results Univariate analysis showed that the hyomental distance (HMD, the distance between the hyoid bone and the tip of the chin) and the hyomental distance ratio (HMDR, the ratio between HMD in the extension position and the one in the neutral position) might not be suitable indicators in patients with cervical spondylosis. Binary multivariate logistic regression (backward-Wald) analyses identified two independent correlative factors from the cervical mobility indicators that correlated best as a predictor of difficult laryngoscopy: modified Mallampati test (MMT) and C2C6AR (the ratio of the angle between a line passing through the bottom of the second cervical vertebra and a line passing through the bottom of the sixth cervical vertebra in the extension position and the one in the neutral position). The odds ratio (OR) and 95 % CI were 2.292(1.093–4.803) and 0.493 (0.306–0.793), respectively. C2C6AR exhibited the largest area under the curve (0.714; 95 % CI 0.633–0.794). Conclusions C2C6AR based on preoperative X-ray images may be the most accurate predictor of cervical mobility indicators for difficult laryngoscopy in patients with cervical spondylosis. Trial registration The study was registered at the Chinese Clinical Trial Registry ( http://www.chictr.org.cn ; identifier: ChiCTR-ROC-16,008,598) on June 6, 2016.

Abstract Background Predicting difficult airway is challengeable in patients with limited airway evaluation. The aim of this study is to develop and validate a model that predicts difficult laryngoscopy by machine learning of neck circumference and thyromental height as predictors that can be used even for patients with limited airway evaluation. Methods Variables for prediction of difficulty laryngoscopy included age, sex, height, weight, body mass index, neck circumference, and thyromental distance. Difficult laryngoscopy was defined as Grade 3 and 4 by the Cormack-Lehane classification. The preanesthesia and anesthesia data of 1677 patients who had undergone general anesthesia at a single center were collected. The data set was randomly stratified into a training set (80%) and a test set (20%), with equal distribution of difficulty laryngoscopy. The training data sets were trained with five algorithms (logistic regression, multilayer perceptron, random forest, extreme gradient boosting, and light gradient boosting machine). The prediction models were validated through a test set. Results The model’s performance using random forest was best (area under receiver operating characteristic curve = 0.79 [95% confidence interval: 0.72–0.86], area under precision-recall curve = 0.32 [95% confidence interval: 0.27–0.37]). Conclusions Machine learning can predict difficult laryngoscopy through a combination of several predictors including neck circumference and thyromental height. The performance of the model can be improved with more data, a new variable and combination of models.

Abstract Background Cleft lip and palate is one of the commonest congenital anomalies, which have an impact on feeding, speech, and dental development away from the significant psychosocial sequel. Early surgical repair aims to restore appearance and function, and the modern techniques can leave many defects undetectable. Therefore, the anesthetic challenge facing the pediatric airway with such abnormalities is still of a great impact. The aim of our study among 189 patients enrolled is to correlate alveolar gap and maximum cleft width measurements as predictors of difficult laryngoscopy and intubation in infants with unilateral complete cleft lip/palate aging from 1 to 6 months. As a secondary outcome, their weight is to be correlated too as another parameter. Results The alveolar gap and maximum cleft width are both of equal high predictive power (p value ≤ 0.001) with 100% sensitivity for both and specificity of 76.10% and 82.39% respectively, with a cut off value of ≤ 10 mm and 11 mm for these dimensions respectively, and odds ratio of incidence of difficult intubation is 4.18 and 5.68 respectively, while body weight ≤ 5.75 kg has an odds ratio of 2.32. Conclusion Alveolar cleft and maximum cleft width can be used as predictors for anticipation of difficult laryngoscopy and intubation infant patients with unilateral complete cleft lip and palate, while body weight ≤ 5.75 kg increases the risk more than twice.

Background/aim: The aim of this study is to research the incidence of difficult airways and the effectiveness of anthropometric measurements and clinical tests used to predict difficult airways in patients undergoing head and neck surgery. Materials and methods: This study was performed on a total of 200 patients over the age of 18 who underwent head and neck surgery between December 2019 and March 2020. The demographic data of the patients in the preoperative period, previous operations/radiotherapy history applied to the head and neck region, and obstructive sleep apnea syndrome symptoms were recorded. In the physical examination, the jaw structure, mouth opening, jaw movement, and tooth structure of the patients, modified Mallampati classification, head and neck movements, neck circumference, thyromental and sternomental distance, atlantooccipital joint mobility, upper lip bite test, Wilson risk scoring, and Cormack-Lehane classification were evaluated. Results: The difficult laryngoscopy rate was identified as 19%, and the difficult intubation rate as 8%. Operation history related to head and neck (p = 0.002), presence of at least two of the obstructive sleep apnea syndrome symptoms (p = 0.008), Modified Mallampati score (p = 0.009), Wilson risk score (p = 0.004), upper lip bite test (p < 0.0001) and mouth opening (p = 0.001) were found to be associated with difficult laryngoscopy. Modified Mallampati score (p = 0.002), Wilson risk score (p < 0.0001), upper lip bite test (p < 0.0001), mouth opening (p < 0.0001), sternomental distance (p = 0.003), Atlantooccipital joint mobility (p = 0.001), and Cormack-Lehane classification (p < 0.0001) were found to be associated with difficult intubation. According to multiple logistic regression analysis, the results obtained for sternomental distance and mouth opening were OR 0.8, 95% CI 0.6-1.1 and OR 0.2, 95% CI 0.1-0.4, respectively. Conclusion: In patients who underwent head and neck surgery, it was observed that the frequency of difficult airway was higher, and particularly the Modified Mallampati score, Wilson risk score, upper lip bite test, and mouth opening were associated with both difficult laryngoscopy and difficult intubation. [ABSTRACT FROM AUTHOR]

Abstract Background Routine preoperative methods to assess airway such as the interincisor distance (IID), Mallampati classification, and upper lip bite test (ULBT) have a certain risk of upper respiratory tract exposure and virus spread. Condyle-tragus maximal distance(C-TMD) can be used to assess the airway, and does not require the patient to expose the upper respiratory tract, but its value in predicting difficult laryngoscopy compared to other indicators (Mallampati classification, IID, and ULBT) remains unknown. The purpose of this study was to observe the value of C-TMD to predict difficult laryngoscopy and the influence on intubation time and intubation attempts, and provide a new idea for preoperative airway assessment during epidemic. Methods Adult patients undergoing general anesthesia and tracheal intubation were enrolled. IID, Mallampati classification, ULBT, and C-TMD of each patient were evaluated before the initiation of anesthesia. The primary outcome was intubation time. The secondary outcomes were difficult laryngoscopy defined as the Cormack-Lehane Level > grade 2 and the number of intubation attempts. Results Three hundred four patients were successfully enrolled and completed the study, 39 patients were identified as difficult laryngoscopy. The intubation time was shorter with the C-TMD>1 finger group 46.8 ± 7.3 s, compared with the C-TMD1 finger group 98.9% than in the C-TMD

Background and Aims: Thyromental height test (TMHT) has revealed good potentials for predicting difficult laryngoscopy view (DLV) in non-obese patients, but its accuracy in obese patients is not evident. This study aimed to assess the validity of TMHT as a predictor of DLV in obese surgical patients. Methods: 105 patients, aged 18–60 years, with body mass index (BMI) >30 kg/m2, scheduled for elective surgeries under general anaesthesia with an endotracheal tube inserted using conventional laryngoscope were included. Airway was assessed with TMHT, modified Mallampati test (MMT), neck circumference (NC) and NC/TMHT ratio. The DLV was defined as Cormack–Lehane grade ≥3. The primary endpoint was the validity of TMHT as a predictor of DLV. The secondary endpoints were to compare the accuracy of TMHT with that of the NC, MMT and NC/TMHT ratio as predictors of the difficult airway. Results: The BMI was 43.7 ± 6.6 kg/m2. The DLV cases were 23/105 (21.9%). The MMT, TMHT and NC/TMHT ratio had the best predictive ability of DLV with areas under receiver operating characteristic curve of 0.91, 0.92 and 0.80; at cut-off values >2, 7.9, respectively. MMT and TMHT were the only predictors of DLV by multivariate analysis. Conclusion: In obese surgical patients, TMHT is an excellent predictor of DLV when the cut-off value is

Patients with burns of the face and neck are more likely to develop unpredictable difficult airways, thus it is necessary to refine approaches to preoperative prediction of such a condition.The objective: develop a method for airway assessment in patients with burns of the face and neck that can improve the results of tracheal intubation by reducing the incidence of unpredictable difficult airways.Subjects and methods. This study was based on analysis of retrospective (42 patients) and prospective (42 patients) data. At the retrospective stage, before surgery all of the patients had their airways assessed as per El-Ganzouri scale. Based on the results, a cumulative rating scale (CRS) was developed, which effectiveness was assessed by prospective data.Results. The area under the ROC curve was 0.67 (p = 0.027). Sensitivity, specificity, positive predictive value, and negative predictive value made 100%, 37%, 45,2%, and 100% accordingly. The assessment of the newly developed CRS: the area under ROC curve was 0.96 (p ≤ 0.05). Sensitivity, specificity, positive predictive value, and negative predictive value made 90.9, 100, 100, and 96.8% accordingly.Conclusion: The developed cumulative rating scale (CRS) has a better predictive potential for assessing the airways in patients with burns of face and neck versus traditional approaches.

Background: Difficult airway causes unexpected and mortal complications in anesthesia practice. Various screening tests are performed to predict difficult intubation preoperatively. These screening tests are affected by many factors and one of them is ethnic differences. Aims: This study aimed to find the test or tests that best predict difficult laryngoscopy (DVL) in Somalia, one of the East African countries. Study Design: Prospective cross - sectional study Methods: This study including 277 patients over 18 years of age, who were ASA I-II and operated under general anesthesia in elective conditions. All patients were examined with Modified Mallampati (MMP), Mouth opening (MO), Sternomental Distance (SMD), Thyromental Distance (TMD), and Upper lip bite (ULBT) tests preoperatively; and the power of these tests to predict DVL was evaluated. Results: Among the screening tests used, it was determined that the MMP screening test was having the highest rate in predicting DVL when used alone, with -2Log likelihood = 148.045 and Nagelkerke R squared = 0.352 values. Then, all screening tests were analyzed together using the Forward LR method to find the model that could best predict DVL and in the logistic regression analysis, it was found that the model created with ULBT, MO, MMP, and SMD was the model that best predicted DVL. Conclusion: In this study; it was concluded that DVL was best predicted by the ULBT + MMP + MO + SMD model in East Africa. [ABSTRACT FROM AUTHOR]

Introduction: Correct airway management of polytraumatized patients is crucial because of the necessity of securing the airway and providing adequate ventilation without worsening a probable spinal cord injury. Objective: Determine the effect of manual inline stabilization (MILS) on Cormack-Lehane classification and if there is any correlation with body mass index (BMI). Material and methods: In a descriptive study at the Centro Hospitalario del Estado Mayor Presidencial in Mexico City, we included 56 patients with ASA physical status I to IV. The anesthesiologist performed direct laryngoscopy while MILS was performed and observed the CL grade. Immediately after, the patient was repositioned into the sniffing position, direct laryngoscopy was performed, and the CL grade was observed again. Results: The CL grades observed were significantly different between MILS vs. Sniffing position. CL grades were mainly high when positioned in MILS (75% classified as grades III and IV) and diminished significantly when changed to the sniffing position. Conclusion: Improvement of CL grade was observed when changing from MILS to sniffing position. [ABSTRACT FROM AUTHOR]

Background and Aims: Thyromental height test (TMHT) has revealed good potentials for predicting difficult laryngoscopy view (DLV) in non-obese patients, but its accuracy in obese patients is not evident. This study aimed to assess the validity of TMHT as a predictor of DLV in obese surgical patients. Methods: 105 patients, aged 18–60 years, with body mass index (BMI) >30 kg/m2, scheduled for elective surgeries under general anaesthesia with an endotracheal tube inserted using conventional laryngoscope were included. Airway was assessed with TMHT, modified Mallampati test (MMT), neck circumference (NC) and NC/TMHT ratio. The DLV was defined as Cormack–Lehane grade ≥3. The primary endpoint was the validity of TMHT as a predictor of DLV. The secondary endpoints were to compare the accuracy of TMHT with that of the NC, MMT and NC/TMHT ratio as predictors of the difficult airway. Results: The BMI was 43.7 ± 6.6 kg/m2. The DLV cases were 23/105 (21.9%). The MMT, TMHT and NC/TMHT ratio had the best predictive ability of DLV with areas under receiver operating characteristic curve of 0.91, 0.92 and 0.80; at cut-off values >2, <47 mm and >7.9, respectively. MMT and TMHT were the only predictors of DLV by multivariate analysis. Conclusion: In obese surgical patients, TMHT is an excellent predictor of DLV when the cut-off value is <47 mm. [ABSTRACT FROM AUTHOR]