Difficult Airway Prediction Score for Intubation in Emergency Departments: A Retrospective Cohort Study

Objective: Difficult intubation is associated with an increasing number of endotracheal intubation attempts. Repeated endotracheal intubation attempts are in turn associated with an increased risk of adverse events. Clinical prediction tools to predict difficult airway have limited application in emergency airway situations. This study was performed to develop a new model for predicting difficult intubation in the emergency department.Methods: This retrospective study was conducted using an exploratory model at the Emergency Medicine of Ramathibodi Hospital, a university-affiliated super-tertiary care hospital in Bangkok, Thailand. The study was conducted from June 2018 to July 2020. The inclusion criteria were an age of ≥15 years and treatment by emergency intubation in the emergency department. Difficult intubation was defined as a Cormack–Lehane grade III or IV laryngoscopic view. The predictive model and prediction score for detecting difficult intubation were developed by multivariable regression analysis.Results: During the study period, 617 patients met the inclusion criteria; of these, 83 (13.45%) had difficult intubation. Five independent factors were predictive of difficult intubation. The difficult airway assessment score that we developed to predict difficult airway intubation had an accuracy of 89%. A score of >4 increased the likelihood ratio of difficult intubation by 7.62 times.Conclusion: A difficult airway assessment score of >4 was associated with difficult intubation.

Airway assessment and management

This chapter provides detailed, practical and up-to-date information on management of the airway. It demystifies airway terminology, outlines airway assessment, and describes the management of the unanticipated difficult airway in adults. It includes a new section on intubating critically ill patients using the vortex approach, and outlines the equipment and techniques used to aid airway management. It gives practical information on the emergency front of neck airway and strategies to approach the obstructed airway. It explains rapid sequence induction, inhalational induction, awake tracheal intubation, and extubation after difficult intubation. It contains new sections on apnoeic oxygenation and how to manage patients with airborne respiratory viruses.

Consensus Report: The Current Status of Airway Assessment

The article's abstract is not available.

Hyo-Mental Angle and Distance: An Important Adjunct in Airway Assessment of Adult Mucopolysaccharidosis

Background: Mucopolysaccharidosis (MPS) is a rare congenital lysosomal storage disorder with complex airways. High anterior larynx is assessed by thyromental distance (TMD) nasendoscopy. A simpler method to assess this hyoid bone is described. The distance between the central-hyoid and symphysis of the mandible (hyo-mental distance; HMD) and inclination of this line to the horizontal axis (hyo-mental angle; HMA) in neutrally positioned patients is investigated. Methods: HMA, HMD in MPS, and non-MPS were compared, and their correlation with height and weight were assessed. Results: 50 adult MPS patients (M = 32, F = 18, age range = 19–66 years; mean BMI = 26.8 kg/m2) of MPS I, II, III, IV, and VI were compared with 50 non-MPS (M = 25, F = 25; age range = 22–84 years; mean BMI = 26.5 kg/m2). Mean HMA in MPS was 25.72° (−10 to +50) versus 2.42° (−35 to +28) in non-MPS. Mean HMD was 46.5 (25.7–66) millimeters in MPS versus 41.8 (27–60.3) in non-MPS. HMA versus height and weight showed a moderate correlation (r = −0.4, p < 0.05) in MPS and no significant correlation (r < 0.4, p > 0.05) in non-MPS. HMD versus height and weight showed no correlation (r < 0.4, p > 0.05) in both groups. Conclusions: HMA seems more acute in MPS despite nearly the same HMD as non-MPS, signifying a high larynx, which may be missed by TMD.

Comparative Study between two Ultrasound Aided Methods in PreoperativeAssessment of Difficult Airway in Obese Patients

Background Unpredictable difficult laryngoscopy remains a challenge for anaesthesiologists, especially if difficult ventilation occurs. So, accurate airway assessment should always be performed so as to provide appropriate planning and management of expected difficult intubation and to limit any unexpected difficulties. Airway assessment using ultrasound has been proposed recently as a useful, simple and non-invasive bed side tool as an adjunct to clinical methods. Objective To establish whether correlations existed between two ultrasound measurements and the Cormack–Lehane grade during direct laryngoscopy, and whether these measurements are useful in predicting are stricted or difficult view especially in morbid obese individuals. The first is the measurement of the hyomental distance of the patient in neutral position of the neck and in fully extended neck calculating the ratio between both of them. While the second is the measurement of anterior cervical soft tissue thickness at three anatomical levels (hyoid bone, thyrohyoid membrane or ‘pre epiglottic space’ and anterior commissure). We chose these two new measurements from among the various ultrasound assessments made in previous studies because of their simplicity of execution in normal clinical and in emergency settings. Patients and Methods The current study is a prospective comparative clinical trial of assessment of difficult air way using two different ultrasound aided techniques in comparison to Cormack and lehane scoring system. Those patients were chosen upon some inclusion and exclusion criteria; inclusion criteria were (Age of the patient (25-60y), ASA I-II patients, Obese patients with body mass index &gt; 30 kg /m2 and Pts undergoing bariatric surgery) and exclusion criteria were (Pathology of the airway (tumors), Deformity of the airway anatomy (burns, scars), History of facial, cervical, pharyngeal and epiglottis surgery or trauma, Patients with most teeth lost and Patient refusal). Results Regarding U/S measurements in method A patients; the average HMD-neutral of A patients was (53.58±5.33) mm, the average HMD-extension was (58±7.82) mm, and the average HMDR was (1.07±0.06). It showed highly significant decrease in HMD extension and HMDR in difficult group, compared to easy group, in A group of patients (p &lt; 0.01respectively). Non-significant difference as regards HMD-neutral U/S measurements in method A (p &gt; 0.05). Conclusion Ultrasonography can be a valuable adjunct in this aspect of airway assessment. Ultrasound assessment of pre-epiglottic tissue thickness at the level of the thyrohyoid membrane may be useful to predict restricted/difficult direct laryngoscopy and difficult intubation. The ratio of hyomental distance between neutral and extended positions may also be a good predictor of difficult direct laryngoscopy.

A Comparative Study to Evaluate the Efficacy of Virtual Versus Direct Airway Assessment in the Preoperative Period in Patients Presenting for Neurosurgery: A Quest for Safer Preoperative Practice in Neuroanesthesia in the Backdrop of the COVID-19 Pandemic!

Objectives Neurosurgical patients with cervical spine pathologies, craniofacial and craniovertebral junction anomalies, recurrent cervical spine, and posterior fossa surgeries frequently present with an airway that is anticipated to be difficult. Although the routine physical evaluation is nonaerosol-generating, Mallampati scoring, mouth opening, and assessment of lower cranial nerve function could potentially generate aerosols, imposing a greater risk of acquiring severe acute respiratory syndrome Coronavirus 2 (SARS-CoV-2) infection. Moreover, airway evaluation requires the patient to remove the mask, thereby posing a greater risk to the assessing anesthesiologist. Thus, we designed this study to evaluate the efficacy of virtual airway assessment (VAA) done via telemedicine in comparison to direct airway assessment (DAA), and assess the feasibility of VAA as a part of the preanesthetic evaluation (PAE) of patients presenting for neurosurgery in the backdrop of the COVID-19 pandemic. Materials and Methods A total of 55 patients presenting for elective neurosurgical procedures were recruited in this prospective, observational study. The preoperative assessment of the airway was first done by a remote anesthetist via an encrypted video call, using a smartphone which served the purpose of telemedicine equipment, followed by a direct assessment by the attending anesthetist. The following parameters were assessed: mouth opening (MO), presence of any anomalies of tongue and palate, Mallampati classification (MPC) grading, thyromental distance (TMD), upper lip bite test (ULBT), neck movements, and Look-Evaluate-Mallampati-Obstruction-Neck mobility (LEMON) scoring system. Statistical Analysis Demographic parameters were expressed as mean ± SD. Agreement between the values obtained by VAA and DAA parameters were analyzed with the Kappa test. Results We observed a “perfect agreement” between the DAA and VAA with regard to MO. Assessment of ULBT, neck movements, and the LEMON score had an overall “almost perfect agreement” between the DAA and VAA. We also observed a “substantial agreement” between VAA and DAA during the assessment of MPC grading and TMD. Conclusion Our study shows that PAE and VAA via telemedicine can reliably be used as an alternative to direct physical preanesthetic consultation in the COVID-19 scenario. This could reduce unnecessary exposure of anesthesiologists to potential asymptomatic COVID-positive patients, thereby protecting the available skilled workforce, without any significant compromise to patient care.