SummaryThe Pentax-AWS Ò airway scope system is a rigid indirect video laryngoscope with integrated tube guidance. Laryngoscopy and intubation are visualised using a built in LCD monitor which displays the view obtained by a CCD camera mounted in the tip of the laryngoscope. We describe its clinical performance in 320 patients. The Pentax-AWS significantly improved the laryngeal view compared to the Macintosh laryngoscope. Forty-six patients (14%) who were classified as Cormack Lehane glottic view grade 3 or 4 using the Macintosh laryngoscope were classified as grade 1 (45 cases) or 2a (1 case) using the Pentax-AWS airway scope. Laryngeal views measured by percentage of glottic opening score were improved significantly using the Pentax-AWS. Intubation using the Pentax-AWS was successful in all cases, 96% at the first and 4% at the second attempt. The mean (SD) time required to place the tracheal tube was 20 (10) s. The Cormack Lehane grade obtained with the Macintosh blade did not affect the total time to correctly position the tube using the Pentax-AWS. Intubation difficulty scale (score = 0 in 305 patients, score = 1 in 14 and score = 2 in one patient) indicates that tracheal intubation was performed easily in most cases. The Pentax-AWS not only improves the laryngeal view, but its tube guide also facilitates rapid, easy and reliable tracheal intubation under vision. It can be useful in routine anesthesia care and may be advantageous in the situation of unanticipated difficult intubation.

The Pentax-AWS system is a rigid indirect video laryngoscope with integrated tube guidance. Complications associated with this device are not well understood. We report two cases of epiglottis malposition during intubation with the Pentax-AWS. The standard technique of using the Pentax-AWS system involves direct elevation of the epiglottis for exposure of the vocal cords. The blade tip should be passed posterior to the epiglottis for laryngeal exposure, but pressure on the anterior surface of the epiglottis by the tip can rarely happen even during the correct maneuver. Although the Pentax-AWS provides clear images of the airway structures, it is sometimes difficult to observe the epiglottis continuously because the camera is located beneath the blade tip. Consequently, the view of the epiglottis from the camera may be impeded by the blade tip and may result in undiagnosed epiglottis malposition. The AWS's structural feature and its approach to the larynx can be associated with increased chance of unexpected epiglottis folding. It is particularly important to confirm normal position of the epiglottis during withdrawal of the device to prevent this complication.

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Introduction: Recently, the effectiveness of the EA during CPR has been questioned. For some time, we have been analyzing the cerebral tissue oxygen saturation observed during CPR. During AHA 2014, we reported the possibility that an increase in the cerebral tissue oxygenation index (TOI) would predict the recovery of spontaneous circulation (ROSC). This time, we report the results of our clinical study about the relationship between the EA and changes in TOI. Methods: In 59 patients undergoing out-of-hospital cardiac arrest, the blood pulsation waveform and TOI in the brain were continuously monitored with the NIRO-200NX system (Hamamatsu Photonics K.K., Japan) using its pulse-observing mode (NIRO-Pulse mode). The total number of EAs was 86 and, as shown in the figure, the initial and terminal TOIs in the CPR before EA (2 minutes) and the initial and terminal TOIs in the CPR after EA (2 minutes) were measured. Results: The initial and terminal TOIs before EA were 37.6±7.2% and 40.0±7.2% respectively, and the increase in TOI during the CPR (αTOI) was 2.4±3.4%. On the other hand, the initial and terminal TOIs after EA were 37.6±6.6% and 44.0±8.4% respectively, and the αTOI was 6.5±4.8%. Discussion: Since the observation of blood pulsation is not possible with conventional cerebral oxygenation monitors, the relationship between the administration of CPR and changes in cerebral tissue oxygen saturation has not been made clear. However with the NIRO-Pulse mode, the changes in TOI caused by CPR are clearly observed. And, our observation that the terminal TOI and αTOI in the CPR after EA were significantly higher than those before EA suggests that cerebral tissue oxygen saturation is improved by EA. On the other hand, the increase in TOI caused by EA (αTOI) has a certain variation, which suggests the most effective time to administer epinephrine would exist and its effects would differ depending on each patient.