Ryosuke Mihara

Comparison of Direct and Indirect Laryngoscopes in Vomitus and Hematemesis Settings: A Randomized Simulation Trial.

Background. Videolaryngoscopes may not be useful in the presence of hematemesis or vomitus. We compared the utility of the Macintosh laryngoscope (McL), which is a direct laryngoscope, with that of the Pentax-AWS Airwayscope (AWS) and McGRATH MAC (McGRATH), which are videolaryngoscopes, in simulated hematemesis and vomitus settings. Methods. Seventeen anesthesiologists with more than 1 year of experience performed tracheal intubation on an adult manikin using McL, AWS, and McGRATH under normal, hematemesis, and vomitus simulations. Results. In the normal setting, the intubation success rate was 100% for all three laryngoscopes. In the hematemesis settings, the intubation success rate differed significantly among the three laryngoscopes (P = 0.021). In the vomitus settings, all participants succeeded in tracheal intubation with McL or McGRATH, while five failed in the AWS trial with significant difference (P = 0.003). The intubation time did not significantly differ in normal settings, while it was significantly longer in the AWS trial compared to McL or McGRATH trial in the hematemesis or vomitus settings (P < 0.001, compared to McL or McGRATH in both settings). Conclusion. The performance of McGRATH and McL can be superior to that of AWS for tracheal intubation in vomitus and hematemesis settings in adults.

Comparison of McGrath and Pentax-AWS Airwayscope for tracheal intubation by anaesthesiologists during chest compression in a manikin: A randomised crossover trial.

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Utility of gum-elastic bougie for tracheal intubation during chest compressions in a manikin: a randomized crossover trial

PURPOSE The utility of the gum-elastic bougie (GEB) as an assistive device for tracheal intubation during chest compressions has not been sufficiently validated. This study aimed to compare the utility of the GEB during chest compressions on an adult manikin. METHODS Seventeen novice physicians performed tracheal intubation on an adult manikin using the GEB with or without chest compressions. Intubation success rate, intubation time, subjective difficulty of laryngoscopy, and tube passage through the glottis were measured. P < .05 was considered as significantly different. RESULTS All novice physicians successfully secured the airway without chest compression with and without the GEB. In contrast, during chest compressions, 7 failed without the GEB, whereas only 1 failed with the GEB (P = .007). Intubation time was significantly longer with chest compressions regardless of GEB use (P < .001). Both laryngoscopy and tube passage through the glottis were perceived as significantly more difficult with chest compressions, regardless of GEB use (P < .001). Subjective difficulty of tube passage through the glottis during chest compression was perceived as significantly more easy by GEB application (P < .001). CONCLUSIONS These findings suggest that the GEB facilitates tracheal intubation during chest compressions performed by novice physicians in adult simulations.

Comparison of Quick Track and Melker for emergent invasive airway management during chest compression: A crossover simulation trial.

In our case, we used 30 ml of air, and this may have exceeded the volume required by this particular patient. As we did not use cuff manometry during the operation, the intracuff pressure is unknown. In practice, there is a poor correlation between the intracuff pressure and the ‘compression’ pressure exerted on the tissues. Due to this poor correlation, simply measuring the intracuff pressure might not be very helpful.

Evaluation of gum-elastic bougie combined with direct and indirect laryngoscopes in vomitus setting: A randomized simulation trial

Purpose: Videolaryngoscopes may not be useful in the presence of vomitus due to blurred images on the monitor. The objective of our study is to compare the utility of gum‐elastic bougie (GEB) application for tracheal intubation with the Macintosh laryngoscope (McL), which is a direct laryngoscope, with that of the Pentax‐AWS Airwayscope® (AWS) and McGRATH® MAC (McGRATH) in simulated vomitus settings. Methods: Sixteen novice doctors performed tracheal intubation on an adult manikin using McL, AWS, and McGRATH with or without GEB under normal and vomitus simulations. Results: In the normal setting the tracheal intubation was successful with the three laryngoscopes regardless of GEB application. In the vomitus setting, the intubation success rate did not significantly improve using McL, while it did using McGRATH or AWS. In the normal settings, GEB application significantly lengthened the intubation time in all three laryngoscopes. By contrast, in the vomitus settings, GEB application significantly shortened the intubation time in all three laryngoscopes. For the comparison of three laryngoscopes, the intubation time did not differ significantly in normal setting, while it was significantly longer in McG and AWS trials than McL trial. Conclusion: The GEB application facilitates the tracheal intubation in the vomitus setting using McGRATH and AWS in adult simulation.

Significance of basic airway management simulation training for medical students.

The American Heart Association cardiopulmonary guidelines recommend not only tracheal intubation (TI), but also bag-valve-mask (BVM) ventilation and supraglottic device (SGD) ventilation in emergent situations. However, given their lack of experience, novice doctors and medical students may find it difficult to implement these recommendations. Here, we used simulation training to have medical students experience the practical difficulties associated with basic airway management. This study was approved by the Research Ethics Committee of Osaka Medical College (No. 1493). From April through July 5, 2015, we conducted simulation training with 32 5th year medical students who had no experience with airway management as a part of their routine training at Osaka Medical College. At our institution, we teach medical students about basic airway management using manikin simulation, BVM ventilation with various techniques, SGD insertion (eg, with laryngeal masks or laryngeal tubes), and TI with the Macintosh laryngoscope. At the end of training, participants rated the difficulty of the three strategies on a Visual Analog Scale, which ranged from 0 mm (extremely easy) to 100 mm (extremely difficult). We also asked the students about the subjective difficulty of laryngoscopy and passage of the tracheal tube through the glottis during TI. Results obtained from each trial were compared using one-way repeated measures analysis of variance. Data are presented as mean ± SD. P b .05 was considered significant. There was no significant difference in subjective difficulty between BVM and SGD (P = .34), while TI was more difficult than BVM and SGD (P b .001) (BVM, 43.7± 23.2 mm; SGD, 44.7±19.3 mm; TI, 88.8±9.1 mm). As for laryngoscopy and tube passage through the glottis during TI, students found laryngoscopy significantly less difficult than tube passage through the glottis (laryngoscopy, 41.6±17.6; tube passage thorough the glottis, 87.2±9.1 mm, P b .001). Physicians often choose TI during resuscitation, which can lead to poor outcomes, and it may be difficult to

Needle guides for venous catheter insertion during chest compressions: a crossover simulation trial ☆

PURPOSE Recent guidelines for cardiopulmonary resuscitation emphasize that all rescuers should minimize the interruption of chest compressions, even for intravenous access. We assessed the utility of needle guides during ultrasound-guided central venous catheterization (US-CVC) with chest compressions via simulation. METHODS Twenty-five anesthesiologists with more than 2years of experience performed US-CVC on a manikin with or without a needle guide and with or without chest compressions. Insertion success rate within 2minutes, insertion time, and subjective difficulty of venous puncture or guide wire insertion were measured. RESULTS In normal trials, 1 participant failed US-CVC without compressions, whereas 6 failed with compressions (P=.04). In needle-guided trials, all participants succeeded without compressions, whereas only 1 failed with compressions (P=.31). Insertion time was significantly longer with chest compressions in both normal and needle-guided trials (P<.001, each). Ultrasound-guided central venous catheterization insertion time in normal trials was significantly longer than in needle-guided trials with compressions (P<.001). Difficulty of operation on a visual analog scale for venous puncture or guide wire insertion was significantly higher in normal trials than in needle-guided trials with compressions. CONCLUSION Needle guides shortened the insertion time and improved the success rate of US-CVC during chest compressions by anesthesiologists in simulations.

The effect of extraction angle on endotracheal tube extubation force: Simulation and randomized clinical trial

Objective To evaluate the extraction force generated at different extubation angles using a manikin simulation and a randomized clinical trial. Methods Simulations were performed on a manikin to assess the force generated at extubation angles of 0°, 30°, 45°, 60°, 90° and 120° relative to the ground. The trial compared extraction force and changes in vital signs in patients undergoing general anaesthesia with tracheal intubation followed by extubation at 60° or 90°. Results The simulation study found that the extubation force was significantly lower at 45° and 60° than at all other extraction angles. In the trial, extubation at 60° resulted in significantly lower extraction force and systolic blood pressure elevation (n = 23) than extubation at 90° (n = 23). Conclusion Findings in a manikin simulation were confirmed by those of a randomized clinical trial, where extubation at 60° required less force than 90°, and was accompanied by less SBP elevation. Extubation at 60° is less invasive than extubation at 90°.

Possibility of lip pulling method not only for prevention of soft tissue injury but also for improved laryngoscopy and tracheal intubation.

Lip injuries are well-recognized complications of laryngoscopy and tracheal intubation [1]. Previous reports suggest that a nonnegligible number of lower lip (22.3%) and upper lip (7.1%) injuries occur during these procedures even in well-equipped operation room [2]. The inherent mechanism of lip injury is caused by the laryngoscopy. When performing laryngoscopy with the Macintosh laryngoscope, physicians are mainly focused onmoving the tongue with the blade and achieving a good view of the glottis. During this process, the upper and lower lips can become squeezed by the lips and teeth, which can lead to injury. This phenomenon may occur more frequently with novice physicians or in emergency situations. Empirically, lip pulling method is applied to minimize soft tissue injury. Typically, assistants or a second anesthesiologist is present during induction of anesthesia for elective surgery. Having these medical staff pull the upper and lower lips outward (upward and downward, respectively) contributes to a substantial reduction in lip injuries (Figure). The clearer view afforded by this additional step could also help minimize tooth and gum injuries as well. We noticed that this lip pullingmethod can give physicians good laryngoscopy view. In emergency situations, sufficient oral and pharyngeal observation is essential for rapid and definite tracheal intubation [4,5]. Here, we propose a modification (addition of a “lip pulling” step) to conventional tracheal intubation that minimizes the incidence of lip injury. In view of the foregoing,we propose the following steps for tracheal intubation during emergency situation: (1) physicians perform head tilting to achieve the sniffing position, (2) physicians open the patients

Manual laryngeal fixation facilitates tracheal intubation during chest compression: A randomized crossover manikin study

Purpose: We compared the effectiveness of external manual laryngeal fixation (MLF) for tracheal intubation during chest compression using three laryngoscopes, the Macintosh laryngoscope (McL), McGRATH® MAC (McGRGTH), and Pentax‐AWS Airwayscope® (AWS) on an adult manikin. Methods: Sixteen novice doctors and 15 experienced anesthesiologists performed tracheal intubation during chest compression on an adult manikin using the McL, McGRATH, and AWS with or without MLF. Tracheal intubation time and intubation success rate were measured. Results: In the AWS trial, all novice and experienced doctors successfully secured the airway with or without MLF during chest compression. In McL and McGRATH trials, MLF significantly improved the rate of successful intubation during chest compression compared to without MLF for novice doctors. While intubation time did not significantly differ with or without MLF in the AWS trial, MLF significantly shortened intubation time in McL and McGRATH trials for both novice and experienced doctors. Conclusion: These findings suggest that MLF facilitates tracheal intubation with the McL and McGRATH during chest compression.