Time to Loss of Preoxygenation in Emergency Department Patients

Spanish Society of Anesthesiology, Reanimation and Pain Therapy (SEDAR), Spanish Society of Emergency and Emergency Medicine (SEMES) and Spanish Society of Otolaryngology, Head and Neck Surgery (SEORL-CCC) Guideline for difficult airway management. Part I

The Airway Management section of the Spanish Society of Anesthesiology, Resuscitation, and Pain Therapy (SEDAR), the Spanish Society of Emergency Medicine (SEMES), and the Spanish Society of Otorhinolaryngology and Head and Neck Surgery (SEORL-CCC) present the Guide for the comprehensive management of difficult airway in adult patients. Its principles are focused on the human factors, cognitive processes for decision-making in critical situations, and optimization in the progression of strategies application to preserve adequate alveolar oxygenation in order to enhance safety and the quality of care. The document provides evidence-based recommendations, theoretical-educational tools, and implementation tools, mainly cognitive aids, applicable to airway management in the fields of anesthesiology, critical care, emergencies, and prehospital medicine. For this purpose, an extensive literature search was conducted following PRISMA-R guidelines and was analyzed using the GRADE methodology. Recommendations were formulated according to the GRADE methodology. Recommendations for sections with low-quality evidence were based on expert opinion through consensus reached via a Delphi questionnaire.

Ease and comfort of pre-oxygenation with high-flow nasal oxygen cannulae vs. facemask: a randomised controlled trial

The Difficult Airway Society recommends that all patients should be pre-oxygenated before the induction of general anaesthesia, but this may not always be easy or comfortable and anaesthesia may often be induced without full pre-oxygenation. We tested the hypothesis that high-flow nasal oxygen cannulae would be easier and more comfortable than facemasks for pre-oxygenation. We randomly allocated 199 patients undergoing elective surgery aged ≥ 10 years to pre-oxygenation using either high-flow nasal oxygen or facemask. Ease and comfort were assessed by anaesthetists and patients on 10-cm visual analogue scale and six-point smiley face scale, respectively. Secondary endpoints included end-tidal oxygen fraction after securing a definitive airway and time to secure an airway. A mean difference (95%CI) between groups in ratings of -0.76 (-1.25 to -0.27) cm for ease of use (p = 0.003) and -0.45 (-0.75 to -0.13) points for comfort (p = 0.006), both favoured high-flow nasal oxygen. A mean difference (95%CI) between groups in end-tidal oxygen fraction of 3.89% (2.41-5.37%) after securing a definitive airway also favoured high-flow nasal oxygen (p < 0.001). There was no significant difference between groups in the number of patients with hypoxaemia (S_p O₂  < 90%) or severe hypoxaemia (S_p O₂  < 85%) lasting ≥ 1 min or ≥ 2 min; in the proportion of patients with an end-tidal oxygen fraction < 87% in the first 5 min after tracheal intubation (52.2% vs. 58.9% in facemask and high-flow nasal oxygen groups, respectively; p = 0.31); or in time taken to secure an airway (11.6 vs. 12.2 min in facemask and high-flow nasal oxygen groups, respectively; p = 0.65). In conclusion, we found pre-oxygenation with high-flow nasal oxygen to be easier for anaesthetists and more comfortable for patients than pre-oxygenation with a facemask, with no clinically relevant differences in end-tidal oxygen fraction after securing a definitive airway or time to secure an airway. The differences in ease and comfort were modest.

Time to Renitrogenation After Maximal Denitrogenation in Healthy Volunteers in the Supine and Sitting Positions

Introduction: Prior to intubation, preoxygenation is performed to denitrogenate the lungs and create an oxygen reservoir. After oxygen is removed, it is unclear whether renitrogenation after preoxygenation occurs faster in the supine vs the sitting position. Methods: We enrolled 80 healthy volunteers who underwent two preoxygenation and loss of preoxygenation procedures (one while supine and one while sitting) via bag-valve-mask ventilation with spontaneous breathing. End-tidal oxygen (ETO2) measurements were recorded as fraction of expired oxygen prior to preoxygenation, at the time of adequate preoxygenation (ETO2 >85%), and then every five seconds after the oxygen was removed until the ETO2 values reached their recorded baseline. Results: The mean ETO2 at completion of preoxygenation was 86% (95% confidence interval 85-88%). Volunteers in both the supine and upright position lost >50% of their denitrogenation in less than 60 seconds. Within 25 seconds, all subjects had an ETO2 of <70%. Complete renitrogenation, defined as return to baseline ETO2, occurred in less than 160 seconds for all volunteers. Conclusion: Preoxygenation loss, or renitrogenation, occurred rapidly after oxygen removal and was not different in the supine and sitting positions. After maximal denitrogenation in healthy volunteers, renitrogenation occurred rapidly after oxygen removal and was not different in the supine and sitting positions.

Difficult lung separation. An insight into the challenges faced during COVID-19 pandemic

Difficult lung isolation or separation in patients undergoing thoracic surgery using one-lung ventilation might be attributed to upper airway difficulty or abnormal anatomy of the lower airway. Additionally, adequate deflation of the surgical lung can impair surgical exposure. The coronavirus disease 2019 (COVID-19) has a harmful consequence for both patients and anesthesiologists. Management of patients with difficult lung isolation can be challenging during the COVID-19 pandemic. Careful planning and preparation, preoperative routine testing, protective personal equipment, standard safety measures, proper preoxygenation, and individualize the patients care are required for successful lung separation. A systematic approach for management of difficult lung separation is centered around securing the airway and providing adequate ventilation using either a blocker or double-lumen tube. Several measures are described to expedite lung collapse.

Airway Management in the Critically Ill Patient

Purpose of Review

This paper will evaluate the recent literature and best practices in airway management in critically ill patients.

Recent Findings

Cardiac arrest remains a common complication of intubation in these high-risk patients. Patients with desaturation or peri-intubation hypotension are at high risk of cardiac arrest, and each of these complications have been reported in up to half of all intubations in critically ill patient populations.

Summary

There have been significant advances in preoxygenation and devices available for performing laryngoscopy and rescue oxygenation. However, the risk of cardiovascular collapse remains concerningly high with few studies to guide therapeutic maneuvers to reduce this risk.