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Lumbar spinal stenosis (LSS) and sagittal imbalance are relatively common in elderly patients. Although the goals of surgery include both functional and radiological improvements, the criteria of correction may be too strict for elderly patients. If the main symptom of patients is not forward-stooping but neurogenic claudication or pain, lumbar decompression without adding fusion procedure may be a surgical option. We performed cost-utility analysis between lumbar decompression and lumbar fusion surgery for those patients. Elderly patients (age > 60 years) who underwent 1–2 levels lumbar fusion surgery (F-group, n = 31) or decompression surgery (D-group, n = 40) for LSS with sagittal imbalance (C7 sagittal vertical axis, C7-SVA > 40 mm) with follow-up ≥ 2 years were included. Clinical outcomes (Euro-Quality of Life-5 Dimensions, EQ-5D; Oswestry Disability Index, ODI; numerical rating score of pain on the back and leg, NRS-B and NRS-L) and radiological parameters (C7-SVA; lumbar lordosis, LL; the difference between pelvic incidence and lumbar lordosis, PI-LL; pelvic tilt, PT) were assessed. The quality-adjusted life year (QALY) and incremental cost-effective ratio (ICER) were calculated from a utility score of EQ-5D. Postoperatively, both groups attained clinical and radiological improvement in all parameters, but NRS-L was more improved in the F-group (p = 0.048). ICER of F-group over D-group was 49,833 US dollars/QALY. Cost-effective lumbar decompression may be a recommendable surgical option for certain elderly patients, despite less improvement of leg pain than with fusion surgery. [ABSTRACT FROM AUTHOR]

Objectives: Intraoperative ultrasonography (IOUS) offers the advantage of providing real-time imaging features, yet it is not generally used. This study aims to discuss the benefits of utilizing IOUS in spinal cord surgery and review related literature. Materials and methods: Patients who underwent spinal cord surgery utilizing IOUS at a single institution were retrospectively collected and analyzed to evaluate the benefits derived from the use of IOUS. Results: A total of 43 consecutive patients were analyzed. Schwannoma was the most common tumor (35%), followed by cavernous angioma (23%) and ependymoma (16%). IOUS confirmed tumor extent and location before dura opening in 42 patients (97.7%). It was particularly helpful for myelotomy in deep-seated intramedullary lesions to minimize neural injury in 13 patients (31.0% of 42 patients). IOUS also detected residual or hidden lesions in 3 patients (7.0%) and verified the absence of hematoma post-tumor removal in 23 patients (53.5%). In 3 patients (7.0%), confirming no intradural lesions after removing extradural tumors avoided additional dural incisions. IOUS identified surrounding blood vessels and detected dural defects in one patient (2.3%) respectively. Conclusions: The IOUS can be a valuable tool for spinal cord surgery in identifying the exact location of the pathologic lesions, confirming the completeness of surgery, and minimizing the risk of neural and vascular injury in a real-time fashion. [ABSTRACT FROM AUTHOR]

Background: Maintaining cervical immobilization is essential during tracheal intubation in patients with unstable cervical spines. When using the Macintosh laryngoscope for intubation in patients with cervical immobilization, substantial neck extension is required for visualization of the glottis. However, the C-MAC D-Blade videolaryngoscope may require less neck extension due to its acute angulation. We hypothesized that C-MAC D-Blade videolaryngoscopic intubation would result in less cervical spine movement than Macintosh laryngoscopic intubation. We compared the effects of C-MAC D-Blade videolaryngoscopic intubation and Macintosh laryngoscopic intubation in terms of cervical spine motion during intubation in patients with simulated cervical immobilization. Methods: In this randomized crossover study, the cervical spine angle was measured at the occiput–C1, C1–C2, and C2–C5 segments before and during tracheal intubation with either a C-MAC D-Blade videolaryngoscope or Macintosh laryngoscope in 20 patients, with application of a neck collar for simulated cervical immobilization. Cervical spine motion was defined as the change in angle measured before and during tracheal intubation. Results: The cervical spine motion at the occiput–C1 segment was measured at 12.1 ± 4.2° and 6.8 ± 5.0° during Macintosh laryngoscopic and C-MAC D-blade videolaryngoscopic intubation, respectively, corresponding to a 44% reduction in cervical spine motion when using the latter device (mean difference, − 5.3; 98.33% CI: − 8.8 to − 1.8; p = 0.001). However, there was no significant difference between the two intubation devices at the C1–C2 segment (− 0.6; 98.33% CI: − 3.4 to 2.2; p = 0.639) or C2–C5 segment (0.2; 98.33% CI: − 6.0 to 6.4; p = 0.929). Conclusions: The C-MAC D-Blade videolaryngoscope causes less upper cervical spine motion than the Macintosh laryngoscope during tracheal intubation of patients with simulated cervical immobilization. Trial registration: This study was registered at ClinicalTrials.gov on June 26, 2018 (NCT03567902). [ABSTRACT FROM AUTHOR]

Background: During videolaryngoscopic intubation, direct epiglottis elevation provides a higher percentage of glottic opening score than indirect epiglottis elevation. In this randomized controlled trial, we compared cervical spine movement during videolaryngoscopic intubation under manual in-line stabilization between the two glottis exposure methods. Methods: Videolaryngoscopic intubation under manual in-line stabilization was performed using C-MAC® D-blade: direct (n = 51) and indirect (n = 51) epiglottis elevation groups. The percentage of glottic opening score was set equally at 50% during videolaryngoscopic intubation in both groups. The primary outcome measure was cervical spine movement during videolaryngoscopic intubation at the occiput–C1, C1–C2, and C2–C5. The secondary outcome measures included intubation performance (intubation success rate and intubation time). Results: Cervical spine movement during videolaryngoscopic intubation was significantly smaller at the occiput–C1 in the direct epiglottis elevation group than in the indirect epiglottis elevation group (mean [standard deviation] 3.9 [4.0] vs. 5.8 [3.4] °, P = 0.011), whereas it was not significantly different at the C1–C2 and C2–C5 between the two groups. All intubations were successful on the first attempt, achieving a percentage of glottic opening score of 50% in both groups. Intubation time was longer in the direct epiglottis elevation group (median [interquartile range] 29.0 [24.0–35.0] vs. 22.0 [18.0–27.0] s, P < 0.001). Conclusions: When performing videolaryngoscopic intubation under manual in-line stabilization, direct epiglottis elevation can be more beneficial than indirect epiglottis elevation in reducing cervical spine movement during videolaryngoscopic intubation at the occiput–C1. Trial registration: Clinical Research Information Service (number: KCT0006239, date: 10/06/2021). [ABSTRACT FROM AUTHOR]

Blocking the abrupt increase in systolic blood pressure associated with autonomic response during bladder hydrodistention in patients with interstitial cystitis/bladder pain syndrome (IC/BPS) is essential for patient safety. We conducted this study to compare autonomic responses during bladder hydrodistention in patients with IC/BPS under general and spinal anaesthesia. Thirty-six patients were randomly allocated to a general anaesthesia (GA, n = 18) or a spinal anaesthesia (SA, n = 18) group. Blood pressure and heart rate were measured continuously and ΔSBP, defined as maximum increases in SBP during bladder hydrodistention from baseline, was compared between groups. Heart rate variability was analysed using electrocardiograms. The post-anaesthesia care unit assessed postoperative pain using a numeric (0–10) rating scale. Our analyses yield a significantly greater ΔSBP (73.0 [26.0–86.1] vs. 2.0 [− 4.0 to 6.0] mmHg), a significantly lower root-mean-square of successive differences in heart rate variability after bladder hydrodistention (10.8 [7.7–19.8] vs. 20.6 [15.1–44.7] ms), and significantly higher postoperative pain scores (3.5 [0.0–5.5] vs. 0.0 [0.0–0.0]) in the GA compared to the SA group. These findings suggest that SA has advantages over GA for bladder hydrodistention in preventing an abrupt increase in SBP and postoperative pain in IC/BPS patients. [ABSTRACT FROM AUTHOR]

Background: The endotracheal cuff pressure depends on the airway pressure during positive-pressure ventilation. A high endotracheal cuff pressure may be related to intraoperative coughing, which can be detrimental during neurosurgery. We investigated the incidence of intraoperative coughing and its association with peak inspiratory pressure (PIP) during neurosurgery under general anesthesia without neuromuscular blockade. Methods: This retrospective study divided 1656 neurosurgical patients who underwent total intravenous anesthesia without additional neuromuscular blockade after tracheal intubation into high (PIP > 21.6 cmH2O, n = 318) and low (PIP ≤ 21.6 cmH2O, n = 1338) PIP groups. After propensity score matching, 206 patients were selected in each group. Demographic, preoperative, surgical, and anesthetic data were collected retrospectively from electronic medical records and continuous ventilator, infusion pump, and bispectral index data from a data registry. Results: Intraoperative coughing occurred in 30 (1.8%) patients, including 9 (0.5%) during the main surgical procedure. Intraoperative coughing was more frequent in the high PIP group than in the low PIP group before (14/318 [4.4%] vs. 16/1338 [1.2%], P < 0.001) and after (13/206 [6.3%] vs. 1/206 [0.5%], P = 0.003) propensity score matching. In multivariable logistic regression analysis after propensity score matching, a high PIP (odds ratio [95% confidence interval] 14.22 [1.81-111.73], P = 0.012), tidal volume divided by predicted body weight (mL/kg, 1.36 [1.09–1.69], P = 0.006), and surgical duration (min, 1.01 [1.00–1.01], P = 0.025) predicted intraoperative coughing. Conclusion: The incidence of intraoperative coughing was 1.8% in neurosurgical patients undergoing general anesthesia without neuromuscular blockade and might be associated with a high PIP. [ABSTRACT FROM AUTHOR]

Background: The endotracheal cuff pressure depends on the airway pressure during positive-pressure ventilation. A high endotracheal cuff pressure may be related to intraoperative coughing, which can be detrimental during neurosurgery. We investigated the incidence of intraoperative coughing and its association with peak inspiratory pressure (PIP) during neurosurgery under general anesthesia without neuromuscular blockade. Methods: This retrospective study divided 1656 neurosurgical patients who underwent total intravenous anesthesia without additional neuromuscular blockade after tracheal intubation into high (PIP > 21.6 cmH2O, n = 318) and low (PIP ≤ 21.6 cmH2O, n = 1338) PIP groups. After propensity score matching, 206 patients were selected in each group. Demographic, preoperative, surgical, and anesthetic data were collected retrospectively from electronic medical records and continuous ventilator, infusion pump, and bispectral index data from a data registry. Results: Intraoperative coughing occurred in 30 (1.8%) patients, including 9 (0.5%) during the main surgical procedure. Intraoperative coughing was more frequent in the high PIP group than in the low PIP group before (14/318 [4.4%] vs. 16/1338 [1.2%], P < 0.001) and after (13/206 [6.3%] vs. 1/206 [0.5%], P = 0.003) propensity score matching. In multivariable logistic regression analysis after propensity score matching, a high PIP (odds ratio [95% confidence interval] 14.22 [1.81-111.73], P = 0.012), tidal volume divided by predicted body weight (mL/kg, 1.36 [1.09–1.69], P = 0.006), and surgical duration (min, 1.01 [1.00–1.01], P = 0.025) predicted intraoperative coughing. Conclusion: The incidence of intraoperative coughing was 1.8% in neurosurgical patients undergoing general anesthesia without neuromuscular blockade and might be associated with a high PIP. [ABSTRACT FROM AUTHOR]

Background: The prognostic nutritional index (PNI) reflects immunonutritional status. We evaluated the effects of postoperative PNI and perioperative changes in the PNI on overall survival (OS) in glioblastoma (GBM) patients.Methods: Demographic, laboratory, and clinical data were retrospectively collected from 335 GBM patients. Preoperative and postoperative PNIs were calculated from serum albumin concentration and lymphocyte count, which were measured within 3 weeks before surgery and 1 month after surgery. Patients were classified into high (n = 206) or low (n = 129) postoperative PNI groups according to the postoperative PNI cutoff value and further classified into four groups according to the cutoff values of the preoperative and postoperative PNIs, as follows: Group HH (both high PNIs, n = 92), Group HL (high preoperative and low postoperative PNI, n = 70), Group LH (low preoperative and high postoperative PNI, n = 37), and Group LL (both low PNIs, n = 136).Results: The median OS was significantly longer in the high postoperative PNI (PNI ≥ 50.2) group than the low postoperative PNI (PNI < 50.2) group (24.0 vs. 15.0 months, p <  0.001). In multivariate analysis, high postoperative PNI was a significant predictor of OS. OS was significantly longer in Group HH than in Group LL and seemed longer in Group HH than in Group HL and in Group LH than in Group LL. OS was not different between Groups HH and LH or between Groups HL and LL.Conclusions: High postoperative PNI was associated with improved OS and perioperative changes in PNI may provide additional important information for prognostic prediction in GBM patients. [ABSTRACT FROM AUTHOR]

Background: Deep brain stimulation (DBS) of the subthalamic nucleus (STN) is an effective treatment for improving the motor symptoms of advanced Parkinson's disease (PD). Accurate positioning of the stimulation electrodes is necessary for better clinical outcomes. Objective: We applied deep learning techniques to microelectrode recording (MER) signals to better predict motor function improvement, represented by the UPDRS part III scores, after bilateral STN DBS in patients with advanced PD. If we find the optimal stimulation point with MER by deep learning, we can improve the clinical outcome of STN DBS even under restrictions such as general anesthesia or non-cooperation of the patients. Methods: In total, 696 4-second left-side MER segments from 34 patients with advanced PD who underwent bilateral STN DBS surgery under general anesthesia were included. We transformed the original signal into three wavelets of 1–50 Hz, 50–500 Hz, and 500–5,000 Hz. The wavelet-transformed MER was used for input data of the deep learning. The patients were divided into two groups, good response and moderate response groups, according to DBS on to off ratio of UPDRS part III score for the off-medication state, 6 months postoperatively. The ratio were used for output data in deep learning. The Visual Geometry Group (VGG)-16 model with a multitask learning algorithm was used to estimate the bilateral effect of DBS. Different ratios of the loss function in the task-specific layer were applied considering that DBS affects both sides differently. Results: When we divided the MER signals according to the frequency, the maximal accuracy was higher in the 50–500 Hz group than in the 1–50 Hz and 500–5,000 Hz groups. In addition, when the multitask learning method was applied, the stability of the model was improved in comparison with single task learning. The maximal accuracy (80.21%) occurred when the right-to-left loss ratio was 5:1 or 6:1. The area under the curve (AUC) was 0.88 in the receiver operating characteristic (ROC) curve. Conclusion: Clinical improvements in PD patients who underwent bilateral STN DBS could be predicted based on a multitask deep learning-based MER analysis. [ABSTRACT FROM AUTHOR]

C-reactive protein and albumin are associated with poor outcomes in critically ill patients. This study aimed to investigate the significance of the C-reactive protein/albumin (CRP/ALB) ratio as a novel prognostic factor for 30-day or 1-year mortality after admission to the postoperative intensive care unit (ICU). This retrospective study was conducted by examining the medical records of postoperative patients aged 19 years or older admitted to the ICU at a tertiary care hospital from January 2007 to July 2016. This study included data on 11,832 postoperative patients in the analysis. The cut-off value of the CRP/ALB ratio was set at 1.75 and 1.58 for 30-day and 1-year mortality after ICU admission, respectively. In postoperative patients with a high CRP/ALB ratio (>1.75 or >1.58), the probability of death within 30 days or 1 year after ICU admission were 30% or 43% higher than that in the group with the least CRP/ALB ratio, respectively (≤1.75 or ≤1.58)(p < 0.05). This study found the CRP/ALB ratio measured immediately after ICU admission to be an independent risk factor for 30-day and 1-year mortality in postoperative patients admitted to the ICU. [ABSTRACT FROM AUTHOR]

Neuromuscular block results in the loss of muscular tone in the upper airway, which might contribute to the increased postoperative airway morbidity followed by ProSeal laryngeal mask airway (PLMA) insertion. We compared the pharyngolaryngeal discomfort exerted by the PLMA according to the neuromuscular block. One hundred sixty patients undergoing surgery for breast disease or inguinal hernia were anesthetized with propofol and remifentanil by target controlled infusion. Rocuronium 0.6 mg/kg (NMBA group, n = 80) or normal saline (No-NMBA group, n = 80) was administered after the loss of consciousness, and one anesthesiologist inserted the PLMA. Postoperative pharyngolaryngeal discomfort was evaluated at postoperative 1 h. Traumatic event was recorded based on the blood trace on the surface of the PLMA cuff. Insertion time, insertion attempt number, sealing pressure, and fiberoptic brochoscopic grades were evaluated. Patients’ characteristics and the PLMA insertion condition (insertion time, successful insertion attempt number, fiberoptic bronchoscopic grade, and sealing pressure) were similar between the two groups. The PLMA can be successfully inserted in non-paralyzed patients with less postoperative pharyngolaryngeal discomfort than when a neuromuscular blocking agent is used (13.8% vs. 30.0%, P = 0.021). The incidence of traumatic events is also reduced when no neuromuscular blocking agent is used (16.3% vs. 32.5%, P = 0.026). Regardless of whether or not a surgical procedure requires muscular relaxation, there is no need to administer neuromuscular blocking agents solely for the purpose of PLMA insertion. Trial Registration: ClinicalTrials.gov [ABSTRACT FROM AUTHOR]

Background Prophylactic fluid preloading before spinal anesthesia has been a routine procedure to prevent maternal hypotension during cesarean delivery. Unlike colloid, timing of infusion of crystalloid may be important because of its short stay in intravascular space. We hypothesized that crystalloid loading just after intrathecal injection compared to preload would be more effective in preventing maternal hypotension. Methods In this prospective controlled study, sixty parturients were randomized to receive 15 ml/kg of crystalloid before (preload group) or after (coload group) intrathecal drug injection for spinal anesthesia. Hypotension was defined if systolic arterial pressure decreased below 80% of baseline and ephedrine was administered to treat hypotension. The incidence of hypotension and the total dose of ephedrine were checked. Blood pressure, heart rate and nausea before childbirth were assessed. Neonatal outcomes were evaluated with Apgar scores and umbilical blood gas analysis. Results The incidence of hypotension was lower in the coload group compared to the preload group (53% vs. 83%, P = 0.026). The blood pressure showed the bigger drop during spinal anesthesia in the preload group (34 ± 13 vs. 25 ± 10 mmHg, P = 0.002) and smaller dose of ephedrine was required in the coload group (7.5 [0-30] vs. 15 [0-40] mg, P = 0.015). The incidence of nausea was also lower in the coload group (27% vs. 60%, P = 0.019). Neonatal outcome measures were comparable between two groups. Conclusions In case of using crystalloids for cesarean delivery, coload is more effective than preload for the prevention of maternal hypotension after spinal anesthesia. [ABSTRACT FROM AUTHOR]

We hypothesized that external laryngeal manipulation would reduce cervical spine motion during video laryngoscopic intubation under manual in-line stabilization by reducing the force required to lift the videolaryngoscope. In this randomized crossover trial, 27 neurointerventional patients underwent two consecutive videolaryngoscopic intubation attempts under manual in-line stabilization. External laryngeal manipulation was applied to all patients in either the first or second attempt. In the second attempt, we tried to reproduce the percentage of glottic opening score obtained in the first attempt. Primary outcomes were cervical spine motion during intubation at the occiput-C1, C1–C2, and C2–C5 segments. The intubation success rate (secondary outcome measure) was recorded. Cervical spine motion during intubation at the occiput-C1 segment was significantly smaller with than without external laryngeal manipulation (7.4° ± 4.6° vs. 11.5° ± 4.8°, mean difference −4.1° (98.33% confidence interval −5.8° to −2.3°), p < 0.001), showing a reduction of 35.7%. Cervical spine motion during intubation at the other segments was not significantly different with versus without external laryngeal manipulation. All intubations were achieved successfully regardless of the application of external laryngeal manipulation. External laryngeal manipulation is a useful method to reduce upper cervical spine motion during videolaryngoscopic intubation under manual in-line stabilization. [ABSTRACT FROM AUTHOR]

Background: The cross-sectional area of the subclavian vein (csSCV) is a crucial factor in the successful catheterization of the subclavian vein. This randomized controlled study investigated the effects of the csSCV on landmark-based subclavian vein catheterization. Methods: This study was performed using a two-stage protocol. During stage I, the csSCV was measured in 17 patients placed in the supine, 20° ipsilateral tilt, and 20° contralateral tilt positions in a random order. During stage II, landmark-based subclavian vein catheterization was randomly performed in patients placed in either the supine (group S, n = 107) or the ipsilateral tilt (group I, n = 109) position. The primary outcome measure was the csSCV in stage I and the primary venipuncture success rate in stage II. Secondary outcome measures were the time to successful venipuncture, the total catheterization time, the first-pass success rate, and the incidence of mechanical complications during catheterization. Results: The csSCV was significantly larger in the ipsilateral tilt than in either the supine or contralateral tilt position (1.01 ± 0.35 vs. 0.84 ± 0.32 and 0.51 ± 0.26 cm2, P =.006 and <.001, respectively). The primary venipuncture success rate did not differ significantly between the group S and I (57.0 vs. 64.2%, P =.344). There were also no significant differences in the secondary outcome measures of the two groups. Conclusions: The csSCV was significantly larger in patients placed in the ipsilateral tilt than in the supine position, but the difference did not result in better clinical performance of landmark-based subclavian vein catheterization. Trial registration: NCT03296735 for stage I (ClinicalTrials.gov, September 28, 2017) and NCT03303274 for stage II (ClinicalTrials.gov, October 6, 2017). [ABSTRACT FROM AUTHOR]

Background: A tracheal tube stylet can be used to assist successful tracheal intubation, especially during videolaryngoscopic intubation because videolaryngoscopes with a Macintosh-type blade such as McGrath® MAC videolaryngoscope have more acute angle than conventional Macintosh laryngoscope. However, the use of a stylet during tracheal intubation can raise concerns about stylet-induced postoperative airway complications, such as sore throat, subglottic injury, and hoarseness. In this study, we compared the incidence of postoperative airway complications after McGrath® MAC videolaryngoscopic intubation with versus without a stylet in patients with a high Mallampati score. Methods: In 104 patients with Mallampati score III or IV and who were scheduled for lumbar or thoracic spine surgery, McGrath® MAC videolaryngoscopic intubation was performed either with a stylet (group S, n = 52) or without a stylet (group N, n = 52). The primary outcome measure was the incidences of sore throat evaluated at 1 and 24 h postoperatively. Secondary outcome measures were the incidences of subglottic injury and postoperative hoarseness. Results: The incidence of CL grade III in group S and N was 3.8 and 5.8%, respectively. No patient showed CL grade IV. The incidences of sore throat at 1 (26.9 vs 19.2%, P = 0.485) and 24 h (17.3 vs 13.5%, P = 0.786, respectively) postoperatively were not significantly different between the group S and N. However, the incidence of subglottic injury was significantly higher in the group S, compared with the group N (65.4 vs 42.3%, P = 0.030). The incidence of postoperative hoarseness did not differ significantly between the two groups. Conclusions: The use of a stylet during McGrath® MAC videolaryngoscopic intubation did not have a significant impact on the incidence of postoperative sore throat in patients with a high Mallampati score. Avoiding the use of a stylet during intubation with McGrath® MAC videolaryngoscope may reduce the incidence of subglottic injury in such patients. Trial registration: Clinical Research Information Service (identifier: KCT0002427, date of registration: June 12, 2017). [ABSTRACT FROM AUTHOR]

Background: The cross-sectional area of the subclavian vein (csSCV) is an important factor determining the success rate of SCV catheterization. The head-down position increases the csSCV. However, the effects of lateral tilting on subclavian venous cross-sectional area have not yet been explored. In this trial, we test our hypothesis that ipsilateral tilt during right SCV catheterization may significantly increase the csSCV by impeding blood flow to the heart, thereby increasing the primary venipuncture success rate and reducing the complication rate and procedure time.Methods/design: This is a two-staged, prospective, randomized, controlled trial conducted on 237 neurosurgical patients requiring SCV catheterization. Seventeen patients in stage I will be placed in supine, 20° ipsilateral tilt, and 20° contralateral tilt positions in random order. The right csSCV will be measured using ultrasonography at each position. In stage II, 220 patients will be randomly assigned to the ipsilateral tilt group (n = 110) and supine group (n = 110) according to the position for right SCV catheterization. Data on catheterization-related characteristics and complications will be collected during and after catheterization. The primary outcome measures are the right csSCV for stage I and primary venipuncture success rate for stage II. The secondary outcome measures for stage II are time to venipuncture, total catheterization time, first-pass success rate, and complications, such as arterial puncture, hematoma, pneumothorax, air embolism, and catheter misplacement.Discussion: This is the first trial to investigate the effects of the ipsilateral tilt position on right SCV catheterization. We will attest the beneficial effects of the ipsilateral tilt position on the csSCV and the primary venipuncture success rate during right SCV catheterization. Furthermore, comparisons of the first-pass success rate, complications, and total catheterization time during SCV catheterization in the ipsilateral tilt position vs. the supine position will help us determine which position is better for safe and easy SCV catheterization.Trial Registration: ClinicalTrials.gov, ID: NCT03296735 . Registered on 25 September 2017 for stage I; NCT03303274 Registered on 6 October 2017 for stage II. [ABSTRACT FROM AUTHOR]