Yasuaki Koyama

A comparison of the force applied on oral structures during intubation attempts between the Pentax-AWS airwayscope and the Macintosh laryngoscope: a high-fidelity simulator-based study

Objective We sought to determine whether the use of Pentax-AWS Airwayscope (AWS) applied less force on oral structures during intubation attempts than a conventional direct laryngoscope (DL). Design Prospective cross-over study. Participants A total of 37 physicians (9 transitional-year residents, 20 emergency medicine residents and 8 emergency physicians) were enrolled. Interventions We used four simulation scenarios according to the difficulty of intubation and devices and used a high-fidelity simulator to quantify the forces applied on the oral structures. Outcome measures Primary outcomes were the maximum force applied on the maxillary incisors and tongue. Other outcomes of interest were time to intubation and glottic view during intubation attempts. Results The maximum force applied on the maxillary incisors in the normal airway scenario was higher with the use of AWS than that with DL (107 newton (N) vs 77 N, p=0.02). By contrast, the force in the difficult airway scenario was significantly lower with the use of AWS than that of the DL (89 N vs 183 N, p<0.01). Likewise, the force applied on the tongue was significantly lower with the use of AWS than the use of DL in both airway scenarios (11 N vs 27 N, p<0.001 in the normal airway scenario; 12 N vs 40 N, p<0.01 in the difficult airway scenario). Conclusions The use of AWS during intubation attempts was associated with decreased forces applied to oral structures in the simulated difficult airway scenario.

Investigation of 7-benzylidenenaltrexone derivatives as a novel structural antitrichomonal lead compound

We evaluated antitrichomonal effects of δ opioid receptor (DOR) agonists and antagonists. Although all the agonists were inactive, the DOR antagonists BNTX (2a) and its derivatives 2b-d showed antitrichomonal activity with MIC of 20-40 μM. In addition, the development of a more effective synthetic method for the BNTX derivatives was achieved by using the Knoevenagel condensation.

Comparison of the force applied on oral structures during intubation attempts by novice physicians between the Macintosh direct laryngoscope, Airway Scope and C-MAC PM: a high-fidelity simulator-based study

Objective We examined whether the use of Airway Scope (AWS) and C-MAC PM (C-MAC) decreased the force applied on oral structures during intubation attempts as compared with the force applied with the use of Macintosh direct laryngoscope (DL). Design Prospective cross-over study. Participants A total of 35 novice physicians participated. Interventions We used 6 simulation scenarios based on the difficulty of intubation and intubation devices. Outcome measures Our primary outcome measures were the maximum force applied on the maxillary incisors and tongue during intubation attempts, measured by a high-fidelity simulator. Results The maximum force applied on maxillary incisors was higher with the use of the C-MAC than with the DL and AWS in the normal airway scenario (DL, 26 Newton (N); AWS, 18 N; C-MAC, 52 N; p<0.01) and the difficult airway scenario (DL, 42 N; AWS, 24 N; C-MAC, 68 N; p<0.01). In contrast, the maximum force applied on the tongue was higher with the use of the DL than with the AWS and C-MAC in both airway scenarios (DL, 16 N; AWS, 1 N; C-MAC, 7 N; p<0.01 in the normal airway scenario; DL, 12 N; AWS, 4 N; C-MAC, 7 N; p<0.01 in the difficult airway scenario). Conclusions The use of C-MAC, compared with the DL and AWS, was associated with the higher maximum force applied on maxillary incisors during intubation attempts. In contrast, the use of video laryngoscopes was associated with the lower force applied on the tongue in both airway scenarios, compared with the DL. Our study was a simulation-based study, and further research on living patients would be warranted.

Longitudinal acquisition of endotracheal intubation skills in novice physicians

Little is known about the acquisition of intubation skills among novice physicians during their one-year clinical training. Our primary objective was to determine the changes in the intubation skills of novice physicians between prior to the clinical training and after completion of the clinical training. We used data of a prospective longitudinal multicenter data registry developed to investigate factors associated with the improvement of intubation skills among novice physicians. The study participants included 90 postgraduate year 1 physicians in 2015–2016. We used 4 simulation scenarios based on the devices used (direct laryngoscope [DL] and Airway scope [AWS]) and difficulty of intubation (normal and difficult scenarios). As a marker of the intubation skills, we used the force applied on the maxillary incisors and the tongue with each intubation. We compared the data obtained prior to clinical training with those obtained after completion of one-year clinical training. When using DL, compared to prior, significantly less force were applied on the maxillary incisors and the tongue after clinical training in the normal scenario (28.0 N vs 19.5 N, p < 0.001, and 11.1 N vs 8.4 N, p = 0.004). Likewise, when using AWS, compared to prior, significantly less force were applied on the tongue after clinical training in the normal scenario (22.0 N vs 0 N, p < 0.001). The force on the tongue decreased after clinical training but not significant. These associations persisted in the difficult airway scenario. These findings suggest that force applied on oral structures can be quantified as a marker of intubation skills by using high-fidelity simulators, and the assessment of procedural competency is recommended for all novice physicians prior to performing intubation in the clinical setting to improve the quality of emergency care.

Cerebral Tissue Oxygenation Index Using Near-infrared Spectroscopy during Extracorporeal Cardio-pulmonary Resuscitation Predicted Good Neurological Recovery in a Patient with Acute Severe Anemia

We herein report the clinical course of a patient who had a good neurological outcome despite severe anemia, high serum lactate levels, and a long period of time from cardiac arrest (CA) to extracorporeal cardio-pulmonary resuscitation (ECPR) establishment. During the period of resuscitation, the tissue oxygenation index (TOI) values were measured continuously by a near-infrared spectroscopy monitoring device and were kept within the normal range. The TOI seems to reflect cerebral perfusion and the balance between the oxygen supply and demand in the brain during ECPR, thereby predicting the neurological outcome. Continuous TOI monitoring is useful for predicting the neurological outcome during ECPR.

Improving the neurological prognosis following OHCA using real-time evaluation of cerebral tissue oxygenation: a case report

Background The neurological prognosis is poor for patients suffering from out‐of‐hospital cardiac arrest (OHCA), in the absence of bystander cardio pulmonary resuscitation (CPR), and showing asystole as the initial waveform. However, such patients have the potential of resuming social activity if cerebral tissue oxygen saturation can be preserved. Case presentation We recently encountered a 60‐year‐old man who had suffered an OHCA in the absence of bystander CPR, and who successfully resumed complete social activity despite initial asystole and requiring at least 75 min of chest compressions before return of spontaneous circulation (ROSC). In this case, chest compression was appropriately performed concurrently with real‐time evaluation of cerebral tissue oxygenation using near‐infrared spectroscopy (NIRS). As a result, the cerebral tissue oxygenation was well maintained, leading to resumption of social activity. Conclusions Improved neurological prognoses can be expected if OHCA patients with the potential for social activity resumption are identified, using NIRS, and effective cardiopulmonary and cerebral resuscitation is performed while visually checking CPR quality.

Favorskii-Type Rearrangement of the 4,5-Epoxymorphinan Skeleton

The aldol condensation of naltrexone with various aryl aldehydes gives the corresponding 7-benzylidenenaltrexone derivatives in high yields. However, novel C-ring-contracted morphinan compounds were produced when 2-pyridinecarboxaldehyde or its related analogues were used as a coupling partner. The key structural feature was the existence of the tetrahydrofuran ring (4,5-epoxy ring, E-ring) of the morphinan skeleton. The time-resolved in situ IR spectroscopy of the reaction system indicated the short-lived absorption of the distorted cyclopropanone intermediate.

Antitrichomonal activity of δ opioid receptor antagonists, 7-benzylidenenaltrexone derivatives

The 7-benzylidenenaltrexone (BNTX) derivatives 2a-v, 3a-c, 13a-c, and 14a were synthesized from naltrexone (1) and evaluated for their antitrichomonal activity. The structure-activity-relationship studies found that 4-iodo-BNTX (2g) showed the highest activity (IC50=10.5µM) and the affinity for the opioid receptor was less important for antitrichomonal activity against Trichomonas vaginalis. The morphinan skeleton bearing both the double bond for a Michael acceptor and the phenolic hydroxy group would be a specific template for development of antitrichomonal agents. In addition, the mechanism of the antitrichomonal activity of the BNTX derivatives may differ from that of the standard drug, metronidazole.