A Validation Pilot Study Comparing Telemedicine Images to a Face-to-Face Airway Exam for Conducting the Anesthesia Preoperative Airway Evaluation

Telemedicine is a branch of healthcare that uses communication technology to deliver medical information and services between patients and healthcare providers. The applicability of telemedicine is vast and increasingly relevant. There is a lack of research on utilizing telemedicine for remote evaluation of the airway. The primary aim of this pilot study was to validate a telemedical airway exam as a viable alternative to an in-person evaluation. Three anesthesiologists evaluated 48 volunteers by telemedicine and live examination. The telemedical exam consisted of transmitting still images of four established, predictive parameters of difficult airways: Mallampati score;neck extension;ability to prognath;and thyromental distance. Each subject’s telemedical and face-to-face scores were compared to determine their degree of correlation. Still images were taken using standardized positioning with four pictures of mouth opening, neck extension, prognath, and thyromental distance. Data were analyzed using Wilcoxon signed-rank tests and free-marginal multirater kappa analysis. Average respective scores for live versus telemedicine examination were as follows: Mallampati scores were 1.73 versus 2.54;neck extension scores were 3.77 versus 3.60;thyromental distance (measured in finger breadths) was 2.95 versus 2.92;and prognath scores were 0.97 versus 0.94. There was no difference in grading of thyromental distance or prognathy ability between live and telemedical exams, and interrater reliability was very good for both parameters. This study supports telemedicine as a reliable tool for preoperative anesthesia airway exams to identify airway difficulties. This may be especially useful as an alternative in patients with COVID-19 undergoing urgent surgery.

Method for Single Intravenous Anesthetic Infusion in a Rodent Model

Venous catheterization, endotracheal intubation, and mechanical ventilation are necessary for performing total intravenous general anesthesia in rats. Intubation and IV cannulation of the rat is challenging because of the animals’ small size and the lack of equipment specifically designed for the restricted anatomical dimensions. Here, we present methods for tail venous catheterization and intubation that are quickly learned by the provider with clinical operating room experience but lack experience in the lab. For tail venous catheterization, each rat (n = 20) was gently restrained in a rat chamber;its tail was placed in warm water for 10 minutes, and a 24 gauge intravenous catheter was inserted into the lateral tail vein. The catheter was fixed in place using tape and attached to a T-connector for drug administration. A bolus of propofol (n = 10), ketamine (n = 7), or etomidate (n = 3) was administered to achieve rapid deep anesthesia. Once anesthetized, rats were intubated with the aid of a modified pediatric laryngoscope. The standard miller blade 0 was cut on each side for approximately 2/3 of the total blade length to remove a total of half the width. After the ventilator was properly set, the rats’ vital signs and metabolic status were monitored. Throughout the one-hour infusion, the rats’ physiologic parameters were maintained within normal range. These results indicate that intravenous general anesthesia can be performed effectively and safely in small animals using the refined catheterization and intubation methods tested in this study. These techniques are easily reproducible and learned as they mimic the tools and strategies commonly used in the OR.

A Non-Blinded, Case Controlled Pilot Study to Evaluate a Novel Mask Ventilation Technique in Patients with Established Risk Factors for Difficult Mask Ventilation

Traditionally, there are two main methods of mask placement during face mask ventilation: one handed (CE) grip and two handed grip (THT). One handed grip is limited by air leaks between mask and patients face on the side opposite to stabilizing hand. Two handed grips provide protection against air leak but require second provider to deliver tidal volumes when using a self inflating bag or anesthesia circuit on manual ventilation. This study introduces modified CE grip which creates a firm seal at patient’s face on both sides of mask, enabling adequate tidal volume delivery with provider’s second hand. Using left hand, provider places the fifth digit along inferior border of body of left mandible. The fourth digit is placed along inferior border of body right mandible. Standing 6 inches to the left and immediately behind a supine patient on an OR table, provider rotates clockwise 45 degrees at hip, keeping elbow against their body, and lifts patient’s chin to 45 degrees. Rotational force at hip augments hand strength while tilting chin. The thumb applies pressure along left border of facemask, and the second and third digits apply pressure to right border of facemask. Methods: Patients with known predictors of difficult mask ventilation (Edentulous, bearded, Obstructive sleep apnea (OSA), mallampati 3 or 4) were in experimental group. Normal patients assigned as Controls. After induction of general anesthesia, provider ventilated patient using adult sized facemask. The anesthesia ventilator delivered standardized tidal volumes. TV, airway pressures, HR and O2 saturation were recorded after each breath. Results: All groups, except OSA, showed improvement, in tidal volumes with the novel technique compared to the traditional CE grip. Conclusion: The novel submandibular technique, an important skill, increases tidal volumes during mask ventilation for certain high risk patients.