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Pilot balloon palpation is still a commonly used method to evaluate cuff pressure of the endotracheal tube after intubation. This study determined whether the size of the tracheal tube influenced the accuracy of pilot balloon palpation. A prospective observational analysis of 208 patients intubated with an endotracheal tube of internal diameter (ID) 6.0 or 8.0 was conducted. An anesthesiologist judged the cuff pressure by manual pilot balloon palpation, and then measured the cuff pressure with a pressure gauge. Cuff pressure exceeding 20-30 cmH 2 O was defined as false recognition. The intracuff pressure was significantly higher in ID 6.0 tube than in the ID 8.0 tube (41.9 ± 18.8 cmH 2 O vs. 30.3 ± 11.9 cmH 2 O, p < 0.001). The number of patients that were mistakenly perceived to have appropriate cuff pressure by pilot balloon palpation was significantly higher in the ID 6.0 group compared to the ID 8.0 group (85 (81.7%) vs. 64 (61.5%), p = 0.001). Therefore, a smaller tube size may further increase risk of inaccurate measurement by pilot balloon palpation and although pressure gauge is recommended for all sizes to maximize accuracy, groups with increased risk factors should be targeted for standardized use of the pressure gauge., (© 2023. The Author(s).)

When selecting the nasotracheal tube diameter for nasotracheal intubation, atraumatic introduction of the tube through the nasal passage and a safe location of the tube's cuff and tip should be ensured simultaneously. To maintain safety margin for the tube's cuff and tip from the vocal cords and carina (2 cm and 3 cm, respectively), the maximum allowable proximal-cuff-to-tip distance was calculated as 5 cm less than the measured vocal cords-to-carina distance. The primary aim of this study was to find a single predictive preoperative factor of the nostril size and maximum allowable proximal-cuff-to-tip distance of nasotracheal tubes. The secondary aim was to compare the difference in the safety margin between the maximum allowable proximal-cuff-to-tip distance based on the patient's airway and the actual proximal-cuff-to-tip distance of the selected tube. We used fiberoptic bronchoscope to measure the distance from the vocal cords to the carina for the calculation of the maximum allowable proximal-cuff-to-tip distance. We analyzed the association of preoperative characteristics such as age, sex, height, and weight with the nostril size and maximum allowable proximal-cuff-to-tip distance. The proportion of patients with appropriate locations of both the cuff and tip was evaluated. Sex and height were significant predictive factors of the nostril size and maximum allowable proximal-cuff-to-tip distance, respectively (p = 0.0001 and p = 0.0048). The difference in the safety margin was significantly decreased when the tube diameter was selected based on the nostril size rather than by sex (p<0.0001). The proportion of patients who had the appropriate cuff/tip location was significantly larger (75.2%) when the tube diameter was selected by sex compared to when it was selected by the nostril size (65%) (p<0.0001). It is more suitable to select the nasotracheal tube diameter based on sex rather than by nostril size to ensure the safe location of the tube's cuff and tip simultaneously., Competing Interests: The authors have declared that no competing interests exist.

Objective: Nasotracheal (NT) intubation is commonly applied during head and neck surgery. However, improper tube size and depth may cause complications. In the current study, we investigated whether NT tubes are being appropriately used in terms of size and depth in adult patients., Methods: Nares were sized in 40 patients using standard nasopharyngeal airways (6.0-8.0) before elective surgery under general anesthesia. The largest sized airway that passed easily into the nasopharynx without resistance was considered as a proper size. Using a fiberoptic scope, the distances from the nares to the vocal cords and the nares to the carina were measured. Rates of proper NT tube positioning were calculated with regard to the cuff and distal tip., Results: The most frequent sizes of properly fitted NT tubes were 6.5 and 6.0 in male and female patients, respectively. Positioning of the cuff and distal tip was only appropriate when using a properly sized tube in 26% and 47% of male and female patients, respectively., Conclusion: Care should be taken to determine the insertion depth after placing an NT tube that has been sized to fit the nostril. Moreover, NT tubes of the same diameter may be required in various lengths. Trial registration: Registered at ClinicalTrial.gov; https://clinicaltrials.gov/ct2/show/NCT02876913 ; Registration number NCT02876913.

Introduction: Size 9 and 8 airways for men and women, respectively, have been proposed as most appropriate based on endoscopy. However, a limitation of this guideline is that ventilation was not assessed., Methods: In this retrospective review of prospectively collected data, 149 patients requiring tracheal intubation for general anesthesia were included. The adequacy for manual and pressure-controlled mechanical ventilation and views at the distal end of each airway was assessed using a fiber-optic bronchoscope with various airway sizes (7, 8, 9, 10, and 11)., Results: For men, size 9, 10, and 11 airways permitted clear manual and adequate mechanical ventilation; size 7 and 8 airways caused partially obstructed manual and inadequate mechanical ventilation. On endoscopy, size 7 and 8 airways caused complete obstruction by the tongue; size 10 and 11 airways either touched or passed beyond the tip of the epiglottis. For women, the size 7 airway caused partially obstructed manual and inadequate mechanical ventilation; size 9 and 10 airways provided clear manual and adequate mechanical ventilation. The size 8 airway permitted clear manual ventilation, though mechanical ventilation was inadequate in one patient. On endoscopy, the size 7 airway caused complete obstruction in >50% of women; size 9, 10, and 11 airways either touched or passed beyond the tip of the epiglottis., Conclusions: With respect to adequate ventilation in conjunction with an acceptable endoscopic view, size 9 and size 8 oropharyngeal airways appear to be the most appropriate sizes for clinical use in men and women, respectively., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Background: Two external facial measurements have been recommended as reference criteria for estimating appropriate oropharyngeal airway sizes: the distances between the maxillary incisors to the angle of the mandible, and that from the corner of the mouth to the angle of the mandible., Objective: To compare the two guidelines and to determine the optimal external facial measurements for the selection of an appropriately sized airway in adults., Design: Randomised crossover study., Setting: Operating theatres in a university hospital., Patients: A total of 113 patients requiring tracheal intubation for general anaesthesia., Interventions: Two oropharyngeal airway sizes were selected on the basis of two external facial measurements (tip of the upper central maxillary incisors to the angle of the mandible and corner of the mouth to the angle of the mandible). After assessing manual and pressure-controlled ventilation without an airway, the adequacy of ventilation with each oropharyngeal airway was assessed in a similar manner. Before changing the oropharyngeal airway, the view at the distal end of each airway was evaluated using endoscopy via a fibreoptic bronchoscope., Main Outcome Measures: Ventilation parameters and the endoscopic views at the distal ends of the airways were assessed., Results: In the maxillary incisors to the angle of the mandible group, there was clear manual ventilation through the oropharyngeal airway in all patients, whereas partially obstructed ventilation was observed in 6% of patients in the corner of the mouth to the angle of the mandible group. In the maxillary incisors to the angle of the mandible group, mechanical ventilation through the oropharyngeal airway was adequate in all patients but in the corner of the mouth to the angle of the mandible group, inadequate ventilation was observed in 7% patients. In the maxillary incisors to the angle of the mandible group, the endoscopy did not identify any patient with complete obstruction of the airway by the tongue but in the corner of the mouth to the angle of the mandible group, 40% of patients had complete obstruction by the tongue. In the maxillary incisors to the angle of the mandible group, the tip of the airway passed beyond the tip of the epiglottis in 22% of patients, in contrast, none of the airways in the corner of the mouth to the angle of the mandible group passed beyond the tip of the epiglottis., Conclusion: With regard to adequate ventilation in conjunction with an acceptable endoscopic view, an oropharyngeal airway whose size is based upon the distance from the maxillary incisors to the angle of the mandible is more advantageous than if based upon the distance from the corner of the mouth to the angle of the mandible., Trial Registration: Clinicaltrials.gov identifier: NCT01945411. The clinical trial was registered before patient enrolment.