Approach to Difficult Airway Management

According to the 2013 American Society of Anesthesiology Practice Guidelines for Management of the Difficult Airway, a term “difficult airway” refers to clinical situations in which a likelihood of 1) difficulty with patient cooperation or consent, 2) difficult mask ventilation, 3) difficult supraglottic airway placement, 4) difficult laryngoscopy, 5) difficult intubation, and/or 6) difficult surgical airway is high. Several considerations are important when approaching each individual clinical scenario. An airway management plan should include patient-specific and situation-specific factors that take into account findings of bedside airway evaluation, prior history of intubations, the acuity of the situation requiring intubation, and the level of airway obstruction. The following module provides an overview of these factors along with a brief introduction to specific clinical situations in which some airway management strategies are more suitable.1,2 This review contains 10 figures, 7 tables and 32 references Key words: Difficult airway, intubation, LEMON score, High-Flow Nasal Cannula Oxygenation, THRIVE

LEMON SCORE: A TOOL TO PREDICT DIFFICULT AIRWAY IN ED IN INDIAN SETTING.

Background: Airway management is a critical need in many acutely ill and injured patients. Inadequate delivery of oxygen to brain and other vital structures is the quickest killer. Emergency airway management is the major key for successful resuscitation in ED. Emergency medicine is an emerging branch in India at present and no research study has been conducted to evaluate difficult airway prediction score. Hence this study aimed to find the use of LEMON score as a tool to predict difficult airway in our ED. Methods: All the patients requiring invasive mechanical ventilation with age >12 years, not admitted outside and admitted to the emergency medicine department from July 2017 to September 2019 were included in our study. A total of 67 patients required invasive ventilation and were assessed by LEMON score for difficult intubation. This score is related to number of attempts required and Cormack lehane class of laryngoscopic view while intubation. Results: In the “LOOK EXTERNALLY” the most common finding was edentulous mouth with occurrence of 26.87%. In ‘EVALUATE’ component the most common difficulty was 2-3-2. In MALLAMPATI CLASS 56.71% were class I, 39.39% were class II. In OBSTRUCTION component of LEMON, 98.51% had no obstruction. In NECK MOBILITY component we found that 85.1% subjects had mobile neck and only 15.15% subjects had restricted neck mobility. We observed that the LEMON score is 60% sensitive and 96.15% specific to predict difficult airway. The positive predictive value was 83.33%. Conclusion: This tool can reduce the chance of unexpectedly encountering difficult airway.

Does Video Laryngoscopy or Direct Laryngoscopy affect first pass success rates for intubation among Attending and Non-Attending Emergency Physician in the Emergency Department?

Background: To our knowledge, there has been no study comparing intubation characteristics between attending and non-attending Emergency Physicians in South-East Asia. We aim to identify whether the use of Direct Laryngoscopy (DL) compared to Video Laryngoscopy (VL) affects first pass success rates between Attending Emergency Physicians (AEP) and Non-Attending Emergency Physicians (NAEP). Materials and Methods: Retrospective analysis of data from 2009 to 2016 in an existing airway registry managed by and academic Emergency Department in Singapore. Primary outcome is first pass success intubation rate. The secondary outcome was first pass success rate for difficult intubations. Difficult intubations were defined as LEMON score of more than 1 or more than 1 attempt at intubation. Results: There were 2909 intubation carried out by emergency physicians in the Emergency Department from 2009 to 2016. AEP conducted 1748 intubations while NAEP conducted 1161 intubations. The first pass success rates for AEP was 84.2% while that for NAEP was 67.4%. 86.2% of intubations by AEP were done with a direct laryngoscope. 89.0% of the intubations by NAEP were done with a direct laryngoscope. 18.9% of intubations by the AEP were difficult compared to 35.2% by the NAEP (p<0.01 95% C.I 13.0%-19.6%). First pass success rate with VL was lower than DL for all intubations (OR 0.66, 95% C.I 0.51-0.84). In the subgroup of difficult intubations, VL did not improve first pass success rate among AEP (OR 0.77, 95% C.I 0.38-1.58) but it did for NAEP (OR 2.46, 95% C.I 0.94-6.45). Conclusion: Our study showed that VL has a poorer first pass success rate for all intubations in general. However, specifically for difficult intubations, VL is associated with improved first pass success rates among NAEP.

Main causes of difficult intubation

Difficult or unsuccessful intubation occur in anesthesiologist’s practice infrequently but such situations may have direct threat to a patient’s life. Often mortality associated with anesthesia is caused precisely by difficulties of intubation. The article deals with analyses of the causes of possible difficult intubation in the practice of anesthesiologist and intensivist in planned and emergency situations. Mallampati test, evaluation of thyromantal distance and mobility of atlanto-occipital joint can be used to predict difficult intubation. According to most recent publications, the most effective way to predict it is the «LEMON» score. Ample opportunities for overcoming difficulties of tracheal intubation are created by recently introduced techniques of videolaryngoscopy - different types of video laryngoscope-modifications of Macintosh blades. Their features compared to classic intubation with the use of Macintosh and Magil blades are excellent view and complete visual control of structures of the larynx.