A randomized comparison of three intubation techniques/tube materials for nasotracheal intubation.

PURPOSE: We sought to compare three intubation methods using different intubation techniques/tube materials for tube advancement from the nasal cavity into the oral cavity during nasotracheal intubation. METHODS: We conducted a randomized clinical trial with adult patients scheduled to undergo elective surgery requiring nasotracheal intubation for general anesthesia. Participants were randomly allocated to a polyvinyl chloride (PVC) tube group (group P), PVC tube attached to a rubber catheter group (group PR), or velvet-soft PVC tube group (group V). Tracheal intubation was then performed based on group allocation. The primary outcome was the first-attempt success rate of tube advancement into the oral cavity; secondary outcomes included the time required for tube advancement into the oral cavity, total intubation time, and the incidence of epistaxis. RESULTS: A total of 149 patients were included in the study. The first-attempt success rate in group V (90%) was significantly higher than that in group P (58%) (odds ratio, 6.5; 95% confidence interval [CI], 2.2 to 19.2), but similar to that in group PR (100%). The mean (standard deviation) time required for tube advancement into the oral cavity was significantly shorter in group V (16 [13] sec) than in group PR [40 (10) sec; 95% CI of mean difference, 17 to 30] and group P (26 [16] sec; 95% CI of mean difference, 3 to 16). Total intubation time was longest in group PR. Epistaxis occurred the least in group V. CONCLUSIONS: Among the three intubation techniques/tube materials for nasotracheal intubation, the velvet-soft PVC tube provided the highest first-attempt success rate, most expeditious advancement into the oral cavity, and lowest incidence of epistaxis. STUDY REGISTRATION: ClinicalTrials.gov (NCT04695444); first submitted 30 December 2020.

RéSUMé: OBJECTIF: Nous avons cherché à comparer trois méthodes d'intubation utilisant différentes techniques d'intubation / matériaux de sondes pour l'avancement de la sonde de la cavité nasale dans la cavité buccale pendant l'intubation nasotrachéale. MéTHODE: Des patient·es devant recevoir une intubation nasotrachéale ont été réparti·es au hasard dans un groupe avec sondes en polychlorure de vinyle (PVC) (groupe P), un groupe avec sondes en PVC attachées à un cathéter en caoutchouc (groupe PR) ou un groupe avec sondes en PVC doux comme du velours (groupe V). L'intubation trachéale a ensuite été réalisée en fonction de l'affectation du groupe. Le critère d'évaluation principal était le taux de réussite de la première tentative d'avancement de la sonde dans la cavité buccale; les critères d'évaluation secondaires comprenaient le temps nécessaire à l'avancement de la sonde dans la cavité buccale, la durée totale de l'intubation et l'incidence d'épistaxis. RéSULTATS: Au total, 149 patient·es ont été inclus·es dans l'étude. Le taux de réussite de l'intubation à la première tentative était significativement plus élevé dans le groupe V (90 %) que dans le groupe P (58 %) (rapport de cotes, 6,5; intervalle de confiance à 95 % [IC], 2,2 à 19,2), mais similaire à celui du groupe PR (100 %). Le temps moyen (écart type) nécessaire pour l'avancement de la sonde dans la cavité buccale était significativement plus court dans le groupe V (16 [13] sec) que dans le groupe PR (40 [10] sec; IC 95 % de la différence moyenne, 17 à 30) et dans le groupe P (26 [16] sec; IC 95 % de la différence moyenne, 3 à 16). La durée totale d'intubation était la plus longue dans le groupe PR. C'est dans le groupe V que l'épistaxis a été la moins fréquente. CONCLUSION: Parmi les trois techniques d'intubation/matériaux de sonde pour l'intubation nasotrachéale, le tube en PVC doux comme du velours a fourni le taux de réussite de première tentative le plus élevé, l'avancement le plus rapide dans la cavité buccale et l'incidence d'épistaxis la plus faible. ENREGISTREMENT DE L'éTUDE: ClinicalTrials.gov (NCT04695444); première soumission le 30 décembre 2020.

Comparison of the effects of paratracheal pressure and cricoid pressure on placement of the i-gel® supraglottic airway: a randomized clinical trial.

PURPOSE: Anesthesiologists can use supraglottic airway devices as a rescue technique for failed intubation even in patients with an increased risk of gastric regurgitation. In this randomized study, we aimed to evaluate the effects of cricoid pressure and paratracheal pressure on placement of the i-gel® (Intersurgical Ltd., Wokingham, Berkshire, UK). METHODS: After induction of anesthesia in 76 adult patients, we inserted the i-gel under paratracheal or cricoid pressure, and assessed the success rate of i-gel insertion, resistance during insertion, time required for insertion, accuracy of the insertion location, tidal volumes, and peak inspiratory pressure with or without each maneuver after i-gel insertion. RESULTS: The overall success rate of insertion was significantly higher under paratracheal pressure than under cricoid pressure (36/38 [95%] vs 27/38 [71%], respectively; difference, 24%; 95% confidence interval [CI], 8 to 40; P = 0.006]. Resistance during insertion was significantly lower under paratracheal pressure than under cricoid pressure (P < 0.001). The time required for insertion was significantly shorter under paratracheal pressure than under cricoid pressure (median [interquartile range], 18 [15-23] sec vs 28 [22-38] sec, respectively; difference in medians, -10; 95% CI, -18 to -4; P < 0.001). Fibreoptic examination of the anatomical alignment of the i-gel in the larynx revealed no significant difference in the accuracy of the insertion location between the two maneuvers (P = 0.31). The differences in tidal volume and peak inspiratory pressure with or without the maneuvers were significantly lower with paratracheal pressure than with cricoid pressure (P = 0.003, respectively). CONCLUSIONS: Insertion of the i-gel supraglottic airway was significantly more successful, easier, and faster while applying paratracheal pressure than cricoid pressure. STUDY REGISTRATION: ClinicalTrials.gov (NCT05377346); first submitted 11 May 2022.

RéSUMé: OBJECTIF: Les anesthésiologistes peuvent utiliser des dispositifs supraglottiques comme technique de sauvetage en cas d'échec de l'intubation, même chez les personnes présentant un risque accru de régurgitation gastrique. Dans cette étude randomisée, nous avons cherché à évaluer les effets de la pression cricoïdienne et de la pression paratrachéale sur le positionnement du dispositif i-gel® (Intersurgical Ltd., Wokingham, Berkshire, Royaume-Uni). MéTHODE: Après l'induction de l'anesthésie chez 76 adultes, nous avons inséré l'i-gel en utilisant une pression paratrachéale ou cricoïdienne, et avons évalué le taux de réussite de l'insertion de l'i-gel, la résistance pendant l'insertion, le temps nécessaire à l'insertion, la précision de l'emplacement d'insertion, les volumes courants ainsi que la pression inspiratoire maximale avec ou sans chacune des manœuvres après l'insertion de l'i-gel. RéSULTATS: Le taux global de réussite de l'insertion était significativement plus élevé avec une pression paratrachéale qu'avec une pression cricoïdienne (36/38 [95 %] vs 27/38 [71 %], respectivement; différence, 24 %; intervalle de confiance [IC] à 95 %, 7,6 à 39,8; P = 0,006]. La résistance lors de l'insertion était significativement plus faible en utilisant une pression paratrachéale par rapport à une pression cricoïdienne (P < 0,001). Le temps nécessaire à l'insertion était significativement plus court après avoir exercé une pression paratrachéale plutôt que cricoïdienne (médiane [écart interquartile], 18,4 [15,3­23,1] secondes vs 28,4 [22,3 à 37,8] secondes, respectivement; différence dans les médianes, −10,0; IC 95 %, −18,4 à −3,6; P < 0,001). L'examen par fibre optique de l'alignement anatomique de l'i-gel dans le larynx n'a révélé aucune différence significative dans la précision de l'emplacement d'insertion entre les deux manœuvres (P = 0,31). Les différences de volume courant et de pression inspiratoire maximale avec ou sans les manœuvres étaient significativement plus faibles avec la pression paratrachéale qu'avec la pression cricoïdienne (P = 0,003, respectivement). CONCLUSION: L'insertion du dispositif supraglottique i-gel a été significativement plus réussie, plus facile et plus rapide lors de l'application d'une pression paratrachéale que d'une pression cricoïdienne. ENREGISTREMENT DE L'éTUDE: ClinicalTrials.gov (NCT05377346); soumis pour la première fois le 11 mai 2022.

Usefulness of video laryngoscopy in tracheal intubation at thyroid surgical position for intraoperative neuromonitoring.

This observational study aimed to compare the glottic view between video and direct laryngoscopy for tracheal intubation in the surgical position for thyroid surgery with intraoperative neuromonitoring. Patients scheduled for elective thyroid surgery with intraoperative neuromonitoring were enrolled. After the induction of anesthesia, patients were positioned in the thyroid surgical posture with a standard inclined pillow under their head and back. An investigator assessed the glottic view using the percentage of glottic opening (POGO) scale and the modified Cormack-Lehane grade in direct laryngoscopy and then video laryngoscopy sequentially while using the same McGRATH™ MAC video laryngoscope at once, with or without external laryngeal manipulation, at the surgical position. A total of thirty-nine patients were participated in this study. Without external laryngeal manipulation, the POGO scale significantly improved during video laryngoscopy compared to direct laryngoscopy in the thyroid surgical position (60.0 ± 38.2% vs. 22.4 ± 23.8%; mean difference (MD) 37.6%, 95% confidence interval (CI) = [29.1, 46.0], P < 0.001). Additionally, with external laryngeal manipulation, the POGO scale showed a significant improvement during video laryngoscopy compared to direct laryngoscopy (84.6 ± 22.9% vs. 58.0 ± 36.3%; MD 26.7%, 95% CI = [18.4, 35.0] (P < 0.001). The superiority of video laryngoscopy was also observed for the modified Cormack-Lehane grade. In conclusion, video laryngoscopy with the McGRATH™ MAC video laryngoscope, when compared to direct laryngoscopy with it, improved the glottic view during tracheal intubation in the thyroid surgical position. This enhancement may potentially facilitate the proper placement of the electromyography tracheal tube and prevent tube displacement due to positional change for thyroid surgery.

Optimal Insertion Depth of Central Venous Catheter through the Right Internal Jugular Vein, Verified by Transesophageal Echocardiography: A Prospective Observational Study.

This prospective observational study investigated the optimal insertion depth of the central venous catheter through the right internal jugular vein using transesophageal echocardiography. After tracheal intubation, the anesthesiologist inserted a probe for esophageal echocardiography into the patient's esophagus. The investigators placed the catheter tip 2 cm above the superior edge of the crista terminalis with echocardiography, which was defined as the optimal point. We measured the inserted length of the catheter. Pearson correlation tests were performed with the measured optimal depth and some patient parameters. We made a new formula for placing the catheter at the optimal position. A total of 89 subjects were enrolled in this trial. The correlation coefficient between the measured optimal depth and the patient's parameters was the highest for patient height (0.703, p < 0.001). We made a new formula of 'height (cm)/10 - 1.5 cm'. The accuracy rate of this formula for the optimal zone was 71.9% (95% confidence interval; 62.4 - 81.4%), which was the highest among the previous formulas or guidelines when we compared. In conclusion, the central venous catheter tip was evaluated with transesophageal echocardiography, and we could make a new formula of 'height (cm)/10 - 1.5', which seemed to be better than other previous guidelines.

Comparison of the effect of sevoflurane and propofol on the optic nerve sheath diameter in patients undergoing middle ear surgery.

PURPOSE: During middle ear surgery, the patient's head is turned away from the surgical site, which may increase the intracranial pressure. Anesthetics also affect the intracranial pressure. The optic nerve sheath diameter (ONSD) measured using ultrasonography is a reliable marker for estimating the intracranial pressure. This aim of this study was to investigate the effect of sevoflurane and propofol on the ONSD in patients undergoing middle ear surgery. METHODS: Fifty-eight adult patients were randomized into sevoflurane group (n = 29) or propofol group (n = 29). The ONSD was measured using ultrasound after anesthesia induction before head rotation (T0), and at the end of surgery (T1). The occurrence and severity of postoperative nausea and vomiting (PONV) were assessed 1 h after the surgery. RESULTS: The ONSD was significantly increased from T0 to T1 in the sevoflurane group [4.3 (0.5) mm vs. 4.9 (0.6) mm, respectively; P < 0.001] and the propofol group [4.2 (0.3) mm vs. 4.8 (0.5) mm, respectively; P < 0.001]. No significant difference was observed in the ONSD at T0 (P = 0.267) and T1 (P = 0.384) between the two groups. The change in the ONSD from T0 to T1 was not significantly different between the sevoflurane and propofol groups [0.6 (0.4) mm vs. 0.6 (0.3) mm, respectively; P = 0.972]. The occurrence and severity of PONV was not significantly different between the sevoflurane and propofol groups (18% vs. 0%, respectively; P = 0.053). CONCLUSION: The ONSD was significantly increased during middle ear surgery. No significant difference was observed in the amount of ONSD increase between the sevoflurane and propofol groups.

Effect of head and neck positions on tracheal intubation using a McGRATH MAC video laryngoscope: A randomised, prospective study.

BACKGROUND: Different head and neck positions may affect video laryngoscopy in terms of laryngeal exposure, intubation difficulty, advancement of the tracheal tube into the glottis and the occurrence of palatopharyngeal mucosal injury. OBJECTIVE: We investigated the effects of simple head extension, head elevation without head extension and the sniffing position on tracheal intubation using a McGRATH MAC video laryngoscope. DESIGN: A randomised, prospective study. SETTING: Medical centre governed by a university tertiary hospital. PATIENTS: A total of 174 patients undergoing general anaesthesia. METHODS: Patients were randomly allocated to one of three groups: simple head extension (neck extension without a pillow), head elevation only (head elevation with a pillow of 7 cm and no neck extension) and sniffing position (head elevation with a pillow of 7 cm and neck extension). MAIN OUTCOMES: During tracheal intubation using a McGRATH MAC video laryngoscope in three different head and neck positions, we assessed intubation difficulty by several methods: a modified intubation difficulty scale score, time taken for tracheal intubation, glottic opening, number of intubation attempts, requirements for other manoeuvres (lifting force or laryngeal pressure) for laryngeal exposure and advancement of the tracheal tube into the glottis. The occurrence of palatopharyngeal mucosal injury was evaluated after tracheal intubation. RESULTS: Tracheal intubation was significantly easier in the head elevation group than in the simple head extension ( P  = 0.001) and sniffing positions ( P  = 0.011). Intubation difficulty did not differ significantly between the simple head extension and sniffing positions ( P  = 0.252). The time taken for intubation in the head elevation group was significantly shorter than that in the simple head extension group ( P  < 0.001). A lifting force or laryngeal pressure was required less frequently for tube advancement into the glottis in the head elevation group than in the simple head extension ( P  = 0.002) and sniffing position groups ( P  = 0.012). The need for a lifting force or laryngeal pressure for tube advancement into the glottis was not significantly different between the simple head extension and sniffing positions ( P  = 0.498). Palatopharyngeal mucosal injury occurred less frequently in the head elevation group than in the simple head extension group ( P  = 0.009). CONCLUSION: The head elevation position facilitated tracheal intubation using a McGRATH MAC video laryngoscope compared with a simple head extension or sniffing position. TRIAL REGISTRY NUMBER: ClinicalTrials.gov (NCT05128968).

Comparative surgical outcomes of transoral endoscopic and robotic thyroidectomy for thyroid carcinoma: a propensity score-matched analysis.

BACKGROUND: Surgical outcomes of patients with thyroid carcinoma who underwent transoral endoscopic thyroidectomy vestibular approach (TOETVA) versus transoral robotic thyroidectomy (TORT) were compared. METHODS: Patients who underwent TOETVA or TORT between July 2016 and February 2022 were retrospectively analyzed. TOETVA and TORT groups were propensity score-matched (1:1) based on age, sex, body mass index, surgical extent, tumor size, and presence of thyroiditis. RESULTS: A total of 185 patients underwent transoral thyroidectomy (142 TOETVA and 43 TORT). Final diagnoses consisted of 135 papillary and seven follicular thyroid carcinomas in the TOETVA group and 43 papillary thyroid carcinomas in the TORT group (p = 0.138). Mean operative time was shorter for the TOETVA group than the TORT group (106.3 vs. 158.9 min, p < 0.001), whereas mean hospital stay was longer for the TOETVA group than the TORT group (2.2 vs. 1.9 days, p = 0.031). After 1:1 propensity score matching, each group included 43 patients. Mean operative time was shorter in the TOETVA group than the TORT group (106.2 vs. 158.9 min, p < 0.001), whereas mean hospital stay was longer in the TOETVA group (2.3 vs. 1.9 days, p = 0.031). There was no significant difference in vocal cord palsy incidences between the groups (one transient, one permanent in the TOETVA group vs. none in the TORT group, p = 0.359). The learning curve was 71 cases for TOETVA and 25 cases for TORT. CONCLUSION: TOETVA had shorter mean operative time, and TORT had shorter learning curve and shorter mean hospital stay. Surgeons should be familiar with the advantages and disadvantages of each procedure.

Standardized Intraoperative Neuromonitoring Procedure is Feasible in Transoral Endoscopic Thyroidectomy.

BACKGROUND: Intraoperative neuromonitoring in thyroid surgeries has become popular, but the standardized manner of intraoperative neuromonitoring during transoral endoscopic thyroidectomy vestibular approach (TOETVA) is not well established. This study evaluated the feasibility of using a standardized intraoperative neuromonitoring method for TOETVA. METHODS: Medical records of consecutive patients who underwent TOETVA with intraoperative neuromonitoring were retrospectively reviewed. Patients were positioned before intubation to prevent tube migration, then intubated using video laryngoscopy. The electromyography amplitudes of the vagal nerves and the recurrent laryngeal nerves were checked before (V1, R1) and after (V2, R2) thyroid resection. V1 and V2 signals were evaluated using a long ball tip stimulator with a stimulus current of 3 mA. R1 and R2 signals were obtained using the stimulus current of 1 to 3 mA. RESULTS: Forty-two patients (3 males and 39 females) were included. Lobectomy was performed in 40 patients (95.2%) and total thyroidectomy in 2 (4.8%). Pathologic diagnoses were 30 papillary thyroid carcinomas, 2 follicular thyroid carcinomas, and 9 benign diseases. Conversion to open surgery occurred in 1 patient due to bleeding. Thus, 43 nerves at risk in 41 patients were analyzed. V1 and R1 signals were detected from all nerves. The mean V1 and R1 amplitudes were 738.7±391.4 µV and 804.4±347.5 µV, respectively, and 38 (88.3%) and 39 (90.7%) nerves had R1 and V1 amplitudes of more than 500 µV. There were 2 cases (4.6%) of transient recurrent laryngeal nerve injury. R2 and V2 signals were detected in the 41 remaining nerves. The mean R2 and V2 amplitudes were 917.2±505.2 µV and 715.7±356.2 µV, respectively, and 36 (87.8%) and 32 (78.0%) nerves had respective R2 and V2 amplitudes of more than 500 µV. CONCLUSIONS: Intraoperative neuromonitoring could be performed in a standardized manner in TOETVA, and the quality of intraoperative neuromonitoring was excellent. Further studies are needed to verify the feasibility of the current approach.

Continuous vagal intraoperative neuromonitoring during video-assisted thoracoscopic surgery for left lung cancer: its efficacy in preventing permanent vocal cord paralysis.

OBJECTIVES: We investigated the safety and efficacy of continuous intraoperative neuromonitoring (CIONM) during video-assisted thoracoscopic lobectomy for left lung cancer in preventing recurrent laryngeal nerve injury. METHODS: From August 2015 to March 2020, 22 patients with left lung cancer without CIONM (unmonitored) and 20 patients with left lung cancer with CIONM underwent thoracoscopic lobectomy with complete mediastinal lymph node dissection including 4L dissection. Clinical outcomes from these 2 groups were compared. RESULTS: The incidence of 4L metastasis was 7.14% (3 patients). There was no significant difference in the total number of dissected 4L lymph nodes between the 2 groups (3.23 ± 2.2 in the unmonitored group, 3.95 ± 2.0 in the CIONM group). CIONM was successful in all of the cases. There was no significant difference in the incidence of postoperative vocal cord palsy (22.7% in the unmonitored group, 20% in the CIONM group, P = 1.000). All of the 5 patients (100%) had permanent vocal cord palsy in the unmonitored group. Although statistically insignificant, 75% (3 patients) had total recovery of the vocal cord function, with only 1 patient remaining in permanent vocal cord palsy in the CIONM group. CONCLUSIONS: CIONM was safe and efficient. CIONM might be helpful to avoid permanent vocal cord palsy by immediately warning the surgeon about impending nerve injury, so the surgeon can stop delivering further injury to the recurrent laryngeal nerve.

Comparison of the needle tip location with the operator's position during ultrasound-guided internal jugular vein catheterization: A randomized controlled study.

OBJECTIVE: We hypothesized that when a right-handed operator catheterizes the left internal jugular vein (IJV), the tip of the needle might be positioned closer to the center of the vessel after puncture if the operator is standing in the patient's left axillary line, rather than standing cephalad to the patient. METHODS: The study randomly allocated 44 patients undergoing elective surgery under general anesthesia with planned left central venous catheterization to either conventional (operator stood cephalad to the patient) or intervention (operator stood in the patient's axillary line) groups. The left IJV was catheterized by 18 anesthesiologists. The distance between the center of the vessel and the needle tip, first-attempt success rate, and procedure time were compared. RESULTS: The distance from the needle tip to the center of the IJV after needle puncture was 3.5 (1.9-5.5) and 3.2 (1.7-4.9) cm in the conventional and intervention groups, respectively (P = .47). The first-attempt success rate was significantly higher in the intervention group (100% vs 68.2%, P = .01). Overall time to successful guidewire insertion was faster in the intervention group (P = .007). CONCLUSIONS: There was no significant difference in needle tip position when the right-handed operator was standing in the patient's left axillary line compared to standing cephalad to the patient during left IJV catheterization. However, it increased the first-attempt success rate and reduced the overall time for guidewire insertion.

Administration of neostigmine after tracheal intubation shortens time to successful intraoperative neuromonitoring during thyroid surgery: a randomized controlled trial.

This prospective, randomized controlled trial evaluated the effect of neostigmine for intraoperative neuromonitoring (IONM) during thyroid surgery. Forty subjects undergoing thyroidectomy with IONM, randomized into neostigmine administration after tracheal intubation (Group N, n = 20) or control treatment with normal saline (Group C, n = 20), completed the trial. Electromyography amplitudes of the vagus nerve (V1) were recorded before thyroid dissection. The time from the initial V1 signal check to successful V1 stimulation was recorded. In Group N, all the patients had a successful V1 signal at the first check, whereas ten (50%) patients in Group C had a time delay between the initial V1 check and successful V1 (p < 0.001). The mean delay time among the delayed patients in Group C was 11.2 ± 1.4 min. The mean time from skin incision to successful V1 stimulation was significantly shorter in Group N than in Group C (15.4 ± 2.4 min vs. 19.9 ± 5.7 min, p = 0.003). In Groups N and C, the mean V1 amplitudes were 962.2 ± 434.5 µV vs. 802.3 ± 382.7 µV (p = 0.225), respectively, and the mean R1 amplitudes were 1240.0 ± 836.5 µV vs. 1023.4 ± 455.8 µV (p = 0.316), respectively. There was one bucking event in Group N. In conclusion, neostigmine administration immediately after tracheal intubation can be useful to reverse neuromuscular blockade for successful IONM in thyroid surgeries.

Effectiveness of Cricoid and Paratracheal Pressures in Occluding the Upper Esophagus Through Induction of Anesthesia and Videolaryngoscopy: A Randomized, Crossover Study.

BACKGROUND: Maneuvers for preventing passive regurgitation of gastric contents are applied to effectively occlude the esophagus throughout rapid sequence induction and intubation. The aim of this randomized, crossover study was to investigate the effectiveness of cricoid and paratracheal pressures in occluding the esophagus through induction of anesthesia and videolaryngoscopy. METHODS: After the induction of anesthesia in 40 adult patients, the location of the esophageal entrance relative to the glottis and location of the upper esophagus relative to the trachea at the low paratracheal region were assessed using an ultrasonography, and the outer diameter of the esophagus was measured on ultrasound before and during application of cricoid and paratracheal pressures of 30 N. Then, videolaryngoscopy was performed with the application of each pressure. During videolaryngoscopy, location of the esophageal entrance relative to the glottis under cricoid pressure was examined on the screen of videolaryngoscope, and the upper esophagus under paratracheal pressure was evaluated using ultrasound. The occlusion rate of the esophagus, and the best laryngeal view using the percentage of glottic opening scoring system were also assessed during videolaryngsocopy. Esophageal occlusion under each pressure was determined by inserting an esophageal stethoscope into the esophagus. If the esophageal stethoscope could not be advanced into the esophagus under the application of each pressure, the esophagus was regarded to be occluded. RESULTS: During videolaryngoscopy, esophagus was occluded in 40 of 40 (100%) patients with cricoid pressure and 23 of 40 (58%) patients with paratracheal pressure (difference, 42%; 95% confidence interval, 26-58; P < .001). Both cricoid and paratracheal pressures significantly decreased the diameter of the esophagus compared to no intervention in the anesthetized paralyzed state ( P < .001, respectively). Ultrasound revealed that the compressed esophagus by paratracheal pressure in the anesthetized paralyzed state was partially released during videolaryngoscopy in 17 of 40 patients, in whom esophageal occlusion was unsuccessful. The best laryngeal view was not significantly different among the no intervention, cricoid pressure, and paratracheal pressure (77 [29] % vs 79 [30] % vs 76 [31] %, respectively; P = .064). CONCLUSIONS: The occlusion of the upper esophagus defined by inability to pass an esophageal stethoscope was more effective with cricoid pressure than with paratracheal pressure during videolaryngoscopy, although both cricoid and paratracheal pressures reduced the diameter of the esophagus on ultrasound in an anesthetized paralyzed state.

Association Between Anesthetics and Postoperative Delirium in Elderly Patients Undergoing Spine Surgery: Propofol Versus Sevoflurane.

STUDY DESIGNS: Retrospective Observational StudyObjectives: To compare the incidence of POD after propofol- and sevoflurane-based anesthesia in elderly patients undergoing spine surgery. METHODS: In this study, the medical records of elderly patients ≥ 65 years of age who underwent spine surgery under total intravenous anesthesia with propofol or inhalational anesthesia with sevoflurane were reviewed. The primary outcome was the incidence of POD after propofol- and sevoflurane-based anesthesia. Secondary outcomes included postoperative 30-day complications, length of postoperative hospital stay, associations of patient characteristics, and surgery- and anesthesia-related data with the development of POD, and associations of anesthetics with clinical outcomes such as postoperative 30-day complications, and length of postoperative hospital stay. RESULTS: Of the 281 patients, POD occurred in 29 patients (10.3%). POD occurred more frequently in the sevoflurane group than in the propofol group (15.7% vs. 5.0%, respectively; P=.003). The multivariable logistic regression analysis showed that sevoflurane-based anesthesia was associated with an increased risk of POD compared with propofol-based anesthesia (odds ratio [OR], 4.120; 95% confidence interval [CI], 1.549-10.954; P = .005), whereas anesthetics were not associated with postoperative 30-day complications and the length of postoperative hospital stay. Older age (OR, 1.242 CI, 1.130-1.366; P < .001) and higher mean pain score at postoperative day 1 (OR, 1.338 CI, 1.056-1.696; P = .016) were also associated with an increased risk of POD. CONCLUSIONS: Propofol-based anesthesia was associated with a lower incidence of POD than sevoflurane-based anesthesia in elderly patients after spine surgery.

Evaluation of the conventional and modified aerosol boxes during tracheal intubation in normal and difficult airways: a randomized, crossover, manikin simulation study.

The aim of this study was to evaluate conventional and modified aerosol boxes in terms of intubation time, first-pass intubation success, and mouth-to-mouth distance between the laryngoscopist and patient during tracheal intubation in simulated patients with normal and difficult airways. Sixteen anesthesiologists performed tracheal intubations with direct laryngoscope or three different videolaryngoscopes (McGRATH MAC videolaryngoscope, C-MAC videolaryngoscope, and Pentax-AWS) without an aerosol box or with a conventional or a modified aerosol boxes in simulated manikins with normal and difficult airways. Intubation time, first-pass intubation success, and mouth-to-mouth distance during tracheal intubation were recorded. Compared to no aerosol box, the use of a conventional aerosol box significantly increased intubation time in both normal and difficult airways (Bonferroni-corrected P-value (Pcorrected) = 0.005 and Pcorrected = 0.003, respectively). Intubation time was significantly shorter with the modified aerosol box than with the conventional one for both normal and difficult airways (Pcorrected = 0.003 and Pcorrected = 0.011, respectively). However, no significant differences were found in intubation time between no aerosol box and the modified aerosol box for normal and difficult airways (Pcorrected = 0.336 and Pcorrected = 0.112, respectively). The use of conventional or modified aerosol boxes significantly extended the mouth-to-mouth distances compared to not using an aerosol box during tracheal intubation with each laryngoscope (all Pcorrected < 0.05), and the distances were not different between the conventional and modified boxes in normal and difficult airways. The use of modified aerosol box did not increase intubation time and could help maintain a distance from the simulated patients with normal and difficult airways.

Investigation of potential neuropharmacological activity of neostigmine-glycopyrrolate for intraoperative neural monitoring in thyroid surgery.

Intraoperative neuromonitoring (IONM) is frequently used in thyroid surgery to reduce recurrent laryngeal nerve injury. The use of neuromuscular blockade agent to facilitate tracheal intubation, is a common cause of IONM failure. We performed a retrospective analysis to assess the efficacy of neostigmine-glycopyrrolate as a neuromuscular blockade reversal agent for IONM during thyroid surgery. Rocuronium (0.6 mg/kg) was administered for muscle relaxation. Neostigmine (2 mg) and glycopyrrolate (0.4 mg) were administered immediately after intubation. Cricothyroid muscle-twitch response upon external branch of superior laryngeal nerve stimulation and electromyography amplitudes of vagal and recurrent laryngeal nerves before (V1, R1) and after thyroid resection (V2, R2) were recorded. Fifty patients (23 males, 27 females) were included in the analysis. The diagnoses comprised 43 papillary thyroid carcinomas and seven benign diseases. The mean time between rocuronium injection and neostigmine-glycopyrrolate injection was 5.1 ± 1.2 min, and the mean time from neostigmine-glycopyrrolate injection to successful cricothyroid muscle twitching upon external branch of superior laryngeal nerve stimulation was 21.0 ± 4.5 min. All patients had V1 and R1 amplitudes of more than 500 µV each, with mean V1 and R1 amplitudes of 985.3 ± 471.6 µV and 1177.2 ± 572.7 µV, respectively. Neostigmine-glycopyrrolate was effectively used as a neuromuscular blockade reversal agent for IONM in thyroid surgeries without a significant increase in bucking events. Administration of neostigmine-glycopyrrolate immediately after intubation can be recommended for successful NMB reversal to facilitate IONM during thyroid surgery.

Effect of head and shoulder positioning on the cross-sectional area of the subclavian vein in obese subjects.

OBJECTIVE: Head and shoulder positioning may affect cross-sectional area (CSA) and location of the subclavian vein (SCV). We investigated the CSA of the SCV and the depth of the SCV, depending on the head and shoulder positions. METHODS: In 24 healthy obese volunteers, the short axis ultrasound images of the SCV and adjacent structures were obtained in three different head positions (neutral, 30° turned to the contralateral side, and 30° turned to the ipsilateral side) and two different shoulder positions (neutral and lowered). Images of the right and left SCVs were obtained in the supine and Trendelenburg positions. Subsequently, the CSA and depth of the SCV were measured. RESULTS: Significant differences were found in the CSA of the SCV in different head positions (30° turned to contralateral side vs. neutral: -0.06 cm2, 95% confidence interval [CI], -0.10 to -0.02; Pcorrected = 0.002, 30° turned to contralateral side vs. 30° turned to ipsilateral side: -0.16 cm2, 95% CI, -0.22 to -0.11; Pcorrected < 0.001, Neutral vs. 30° turned to ipsilateral side: -0.10 cm2, 95% CI, -0.14 to -0.07; Pcorrected < 0.001). The CSA of the SCV was significantly different, depending on shoulder positions (neutral vs. lowered: 0.44 cm2, 95% CI, 0.33 to 0.54; Pcorrected < 0.001), and body position (supine vs. Trendelenburg: -0.15 cm2, 95% CI, -0.19 to -0.12; Pcorrected < 0.001). However, the depth of the SCV did not differ with respect to head, shoulder, and body positions. CONCLUSIONS: Ipsilateral 30° head rotation, neutral shoulder position, and Trendelenburg position significantly enhanced the CSA of the SCV in obese participants.

Application of patch stimulator for intraoperative neuromonitoring during thyroid surgery: maximizing surgeon's convenience.

BACKGROUND: Intraoperative neuromonitoring (IONM) is frequently used in thyroid surgery to reduce recurrent laryngeal nerve (RLN) injury by providing the surgeon with real-time feedback on nerve stimulation during dissection. We applied a disposable adhesive patch electrode to a dissecting instrument to transfer electrical stimulation to the dissecting instrument for IONM during thyroid surgery. This study aimed to evaluate the feasibility of using the patch stimulator approach for IONM during thyroid surgery. METHODS: We reviewed the medical records of patients who underwent thyroidectomy using both conventional stimulator and adhesive patch stimulator for IONM. The electromyography (EMG) amplitudes of the vagal and the RLNs before (V1, R1) and after thyroid resection (V2, R2) were alternatively checked with each type of stimulator at the same location of each nerve. RESULTS: Fifteen consecutive patients (4 males, 11 females) were included in this analysis, and a total of 38 nerves (19 vagus nerves and 19 RLNs) were evaluated. No statistically significant differences were seen in the mean amplitudes evoked by the patch stimulator and the conventional probe stimulator for the V1 signal (825.5±394.6 vs. 821.8±360.9 µV, P=0.954), R1 signal (1,044.8±471.2 vs. 1,039.2±507.4 µV, P=0.898), R2 signal (1,037.8±495.0 vs. 938.2±415.8 µV, P=0.948), or V2 signal (812.5±391.9 vs. 787.3±355.7 µV, P=0.975). CONCLUSIONS: The patch stimulator was safely and effectively used for IONM during thyroid surgery and provided similar nerve monitoring responses as the conventional stimulator. This approach may be used to enhance the surgeon's convenience during thyroid surgery.

Comparison of the Conventional Downward and Modified Upward Laryngeal Handshake Techniques to Identify the Cricothyroid Membrane: A Randomized, Comparative Study.

BACKGROUND: Accurate identification of the cricothyroid membrane is crucial for successful cricothyroidotomy. The aim of this study was to compare the conventional downward and modified upward laryngeal handshake techniques in terms of accuracy to identify the cricothyroid membrane in nonobese female patients. METHODS: In 198 anesthetized female patients, the cricothyroid membrane was identified by either the conventional downward laryngeal handshake technique (n = 99) or the modified upward laryngeal handshake technique (n = 99). According to the conventional downward laryngeal handshake technique, the cricothyroid membrane was identified by palpating the neck downward from the greater cornu of the hyoid bone, thyroid laminae, and cricoid cartilage. According to the modified upward laryngeal handshake technique, the cricothyroid membrane was located by moving up from the sternal notch. The primary outcome was the accuracy of identifying the cricothyroid membrane. Secondary outcomes included the accuracy of midline identification and time taken to locate what participants believed to be the cricothyroid membrane. The primary and secondary outcomes according to the technique were analyzed using generalized estimating equations. RESULTS: The cricothyroid membrane could be identified more accurately by the modified upward laryngeal handshake technique than by the conventional downward technique (84% vs 56%, respectively; odds ratio [OR], 4.36; 95% confidence interval [CI], 2.13-8.93; P < .001). Identification of the midline was also more accurate by the modified laryngeal handshake than by the conventional technique (96% vs 83%, respectively; OR, 4.98; 95% CI, 1.65-15.01; P = .004). The time taken to identify the cricothyroid membrane was not different between the conventional and modified techniques (20.2 [16.2-26.6] seconds vs 19.0 [14.5-26.4] seconds, respectively; P = .83). CONCLUSIONS: The modified upward laryngeal handshake technique that involved tracing the trachea and laryngeal structures upward from the sternal notch was more accurate in identifying the cricothyroid membrane than the conventional downward technique in anesthetized female patients.