Airway management should be accompanied by comprehensive documentation, both to inform other healthcare professionals of what has occurred and to inform future care. Videolaryngoscopy is increasingly used instead of direct laryngoscopy to perform tracheal intubation. The relationship between the laryngeal view obtained and ease of tube placement has become uncoupled. Current issues include uncertainties around how best to describe the view obtained on videolaryngoscopy and what that view means for intubation success.

The flow of liquids and gases is relevant to many areas of practice in anaesthesia and critical care medicine. This article describes the principles governing flow, including the differences between laminar and turbulent flow and the factors that influence flow patterns. The Bernoulli principle and the Venturi effect are explained with clinical examples. Additional focus is afforded to high-flow nasal oxygen and jet ventilation therapies.

The value of high-flow nasal oxygen (HFNO) in anaesthetic practice is well recognised. Its roles are diverse, with the potential to oxygenate patients whether they are breathing or apnoeic, and whether they are awake, sedated, or anaesthetised. HFNO is administered without incident to thousands of patients worldwide on a daily basis. Major complications associated with its use are rare. However, a number of fires have now been reported with laser or diathermy use within or adjacent to the airways of patients receiving HFNO.

Ventilation of the lungs is tightly regulated to maintain a PaCO2 that supports optimal acid-base status and an adequate PaO2. Central and peripheral chemoreceptors feed into respiratory control centres in the brainstem. PaO2 exerts its influence mainly through peripheral chemoreceptors, whereas PaCO2 exerts its influence mainly through the central chemoreceptors and, to a much lesser extent, the peripheral chemoreceptors. The tightest physiologic control is over PaCO2. Indeed, a linear relationship exists between PaCO2 and alveolar ventilation through a broad range of PaCO2 values. In contrast, for PaO2, significant stimulation of respiration only occurs at low levels (approximately 8 kPa or less). The combination of hypoxaemia and hypercarbia exerts a synergistic effect on promoting ventilation. Acidosis, whether respiratory or metabolic, is also a potent stimulus for ventilation. Other influences on ventilatory control include airway reflexes to inhaled toxins. Various drugs used in anaesthesia and critical care medicine depress ventilation, most markedly opioids, while others notably caffeine are used to stimulate it. Evidence of disordered control of ventilation is seen in some disease states, the phenomenon of Cheyne-Stokes respiration being particularly well recognized. Measurement of respiratory drive is increasingly used in intensive care to individualize mechanical ventilation.

Airway management is undertaken to deliver oxygen, remove carbon dioxide and protect against pulmonary aspiration. This article describes the equipment utilized by airway providers in order to achieve these aims, aided by their relevant knowledge, skills and experience. The use of this equipment forms the basis of core airway management techniques, including facemask ventilation, use of supraglottic airway devices, laryngoscopy, awake tracheal intubation and front-of-neck access.

AnaesthesiaVolume 79, Issue 2 p. 123-127 Editorial Point-of-care gastric ultrasound: food for thought C. Lyons, C. Lyons Fellow, Consultant Department of Anaesthesia and Peri-operative Medicine, Guy's and St. Thomas' NHS Foundation Trust, London, UKSearch for more papers by this authorK. El-Boghdadly, Corresponding Author K. El-Boghdadly Consultant, Honorary Reader [email protected] orcid.org/0000-0002-9912-717X @elboghdadly Department of Anaesthesia and Peri-operative Medicine, Guy's and St. Thomas' NHS Foundation Trust, London, UK King's College London, London, UK Correspondence to: K. El-Boghdadly Email: [email protected]Search for more papers by this author C. Lyons, C. Lyons Fellow, Consultant Department of Anaesthesia and Peri-operative Medicine, Guy's and St. Thomas' NHS Foundation Trust, London, UKSearch for more papers by this authorK. El-Boghdadly, Corresponding Author K. El-Boghdadly Consultant, Honorary Reader [email protected] orcid.org/0000-0002-9912-717X @elboghdadly Department of Anaesthesia and Peri-operative Medicine, Guy's and St. Thomas' NHS Foundation Trust, London, UK King's College London, London, UK Correspondence to: K. El-Boghdadly Email: [email protected]Search for more papers by this author First published: 28 November 2023 https://doi.org/10.1111/anae.16190 1 Fellow, 2 Consultant, Department of Anaesthesia and Peri-operative Medicine, Guy's and St. Thomas' NHS Foundation Trust, London, UK 3 Honorary Reader, King's College London, London, UK This editorial accompanies an article by Baettig et al., Anaesthesia 2023; 78: 1327–37. Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onEmailFacebookTwitterLinkedInRedditWechat References 1Cook TM, Woodall N, Frerk C, Fourth National Audit Project. Major complications of airway management in the UK: results of the Fourth National Audit Project of the Royal College of Anaesthetists and the Difficult Airway Society. Part 1: anaesthesia. British Journal of Anaesthesia 2011; 106: 617–631. 10.1093/bja/aer058 CASPubMedWeb of Science®Google Scholar 2Baettig SJ, Filipovic MG, Hebeisen M, Meierhans R, Ganter MT. Pre-operative gastric ultrasound in patients at risk of pulmonary aspiration: a prospective observational cohort study. Anaesthesia 2023; 78: 1327–1337. 10.1111/anae.16117 CASPubMedWeb of Science®Google Scholar 3Van de Putte P, Perlas A. The link between gastric volume and aspiration risk. In search of the Holy Grail? Anaesthesia 2018; 73: 274–279. 10.1111/anae.14164 CASPubMedWeb of Science®Google Scholar 4Thomas M, Morrison C, Newton R, Schindler E. Consensus statement on clear fluids fasting for elective pediatric general anesthesia. Paediatric Anaesthesia 2018; 28: 411–414. 10.1111/pan.13370 PubMedWeb of Science®Google Scholar 5 American Society of Anesthesiologists Committee. Practice guidelines for preoperative fasting and the use of pharmacologic agents to reduce the risk of pulmonary aspiration: application to healthy patients undergoing elective procedures. An updated report by the American Society of Anesthesiologists task force on preoperative fasting and the use of pharmacologic agents to reduce the risk of pulmonary aspiration. Anesthesiology 2017; 126: 376–393. 10.1097/ALN.0000000000001452 PubMedWeb of Science®Google Scholar 6Asai T. Who is at increased risk of pulmonary aspiration? British Journal of Anaesthesia 2004; 93: 497–500. 10.1093/bja/aeh234 CASPubMedWeb of Science®Google Scholar 7Kim HJ, Choi YS, Jin JH, Lee B. Management of pulmonary aspiration due to undiagnosed achalasia during induction of general anaesthesia – a case report. Anesthesia and Pain Medicine 2022; 17: 239–244. 10.17085/apm.21102 Google Scholar 8Van de Putte P, Vernieuwe L, Jerjir A, Verschueren L, Tacken M, Perlas A. When fasted is not empty: a retrospective cohort study of gastric content in fasted surgical patients. British Journal of Anaesthesia 2017; 118: 363–371. 10.1093/bja/aew435 CASPubMedWeb of Science®Google Scholar 9Harper NJN, Cook TM, Garcez T, et al. Anaesthesia, surgery, and life-threatening allergic reactions: epidemiology and clinical features of perioperative anaphylaxis in the 6th National Audit Project (NAP6). British Journal of Anaesthesia 2018; 121: 159–171. 10.1016/j.bja.2018.04.014 CASPubMedWeb of Science®Google Scholar 10Pandit JJ, Andrade J, Bogod DG, et al. 5th National Audit Project (NAP5) on accidental awareness during general anaesthesia: summary of main findings and risk factors. British Journal of Anaesthesia 2014; 113: 549–559. 10.1093/bja/aeu313 CASPubMedWeb of Science®Google Scholar 11 Association of Anaesthetists of Great Britain and Ireland. Pre-operative assessment and patient preparation – The Role of the Anaesthetist. January 2010. www.anaesthetists.org/Home/Resources-publications/Guidelines/Pre-operative-assessment-and-patient-preparation-the-role-of-the-anaesthetist-2 (accessed 05/08/2023). Google Scholar 12Joshi GP, Abdelmalak BB, Weigel WA. 2023 American Society of Anesthesiologists Practice Guidelines for preoperative fasting: carbohydrate-containing clear liquids with or without protein, chewing gum, and pediatric fasting duration – a modular update of the 2017 American Society of Anesthesiologists Practice Guidelines for preoperative fasting. Anesthesiology 2023; 138: 132–151. 10.1097/ALN.0000000000004381 PubMedWeb of Science®Google Scholar 13Smith I, Kranke P, Murat I, et al. Perioperative fasting in adults and children: guidelines from the European Society of Anaesthesiology. European Journal of Anaesthesiology 2011; 28: 556–569. 10.1097/EJA.0b013e3283495ba1 PubMedWeb of Science®Google Scholar 14Frykholm P, Disma N, Andersson H, et al. Pre-operative fasting in children: a guideline from the European Society of Anaesthesiology and Intensive Care. European Journal of Anaesthesiology 2022; 39: 4–25. 10.1097/EJA.0000000000001599 PubMedWeb of Science®Google Scholar 15Newton RJG, Stuart GM, Willdridge DJ, Thomas M. Using quality improvement methods to reduce clear fluid fasting times in children on a preoperative ward. Paediatric Anaesthesia 2017; 8: 793–800. 10.1111/pan.13174 Google Scholar 16Joshi GP. Anesthetic considerations in adult patients on glucagon-like peptide-1 receptor agonists: gastrointestinal focus. Anesthesia and Analgesia 2023. Epub 24 October. https://doi.org/10.1213/ANE.0000000000006810. 10.1213/ANE.0000000000006810 Google Scholar 17Arzola C, Carvalho JC, Cubillos J, Ye XY, Perlas A. Anesthesiologists' learning curves for bedside qualitative ultrasound assessment of gastric content: a cohort study. Canadian Journal of Anesthesia 2013; 60: 771–779. 10.1007/s12630-013-9974-y PubMedWeb of Science®Google Scholar Volume79, Issue2February 2024Pages 123-127 ReferencesRelatedInformation

Airway-related articles have featured heavily in the British Journal of Anaesthesia since it was founded in 1923. In the 100 years thereafter, 1102 airway-related articles have been published in the journal, written by 2955 unique authors from 55 different countries. In this editorial, we highlight some of the major publications in airway management and their impact on the specialty. Summaries of the most cited articles are contained within online supplementary material as well as links to all airway-related articles for readers who wish to delve deeper into this body of work.

Summary High‐flow nasal oxygen can be administered at induction of anaesthesia for the purposes of pre‐oxygenation and apnoeic oxygenation. This intervention is claimed to enhance carbon dioxide elimination during apnoea, but the extent to which this occurs remains poorly quantified. The optimal nasal oxygen flow rate for gas exchange is also unknown. In this study, 114 patients received pre‐oxygenation with high‐flow nasal oxygen at 50 l.min ‐1 . At the onset of apnoea, patients were allocated randomly to receive one of three nasal oxygen flow rates: 0 l.min ‐1 ; 70 l.min ‐1 ; or 120 l.min ‐1 . After 4 minutes of apnoea, all oxygen delivery was ceased, tracheal intubation was performed, and oxygen delivery was recommenced when SpO 2 was 92%. Mean (SD) PaCO 2 rise during the first minute of apnoea was 1.39 (0.39) kPa, 1.41 (0.29) kPa, and 1.26 (0.38) kPa in the 0 l.min ‐1 , 70 l.min ‐1 and 120 l.min ‐1 groups, respectively; p = 0.16. During the second, third and fourth minutes of apnoea, mean (SD) rates of rise in PaCO 2 were 0.34 (0.08) kPa.min ‐1 , 0.36 (0.06) kPa.min ‐1 and 0.37 (0.07) kPa.min ‐1 in the 0 l.min ‐1 , 70 l.min ‐1 and 120 l.min ‐1 groups, respectively; p = 0.17. After 4 minutes of apnoea, median (IQR [range]) arterial oxygen partial pressures in the 0 l.min ‐1 , 70 l.min ‐1 and 120 l.min ‐1 groups were 24.5 (18.6–31.4 [12.3–48.3]) kPa; 36.6 (28.1–43.8 [9.8–56.9]) kPa; and 37.6 (26.5–45.4 [11.0–56.6]) kPa, respectively; p < 0.001. Median (IQR [range]) times to desaturate to 92% after the onset of apnoea in the 0 l.min ‐1 , 70 l.min ‐1 and 120 l.min ‐1 groups, were 412 (347–509 [190–796]) s; 533 (467–641 [192–958]) s; and 531 (462–681 [326–1007]) s, respectively; p < 0.001. In conclusion, the rate of carbon dioxide accumulation in arterial blood did not differ significantly between apnoeic patients who received high‐flow nasal oxygen and those who did not.

Editor—Ellis and colleagues1 published a computer modelling exercise in this journal on apnoeic oxygenation at induction of anaesthesia for parturients. They concluded that there is likely to be clinical benefit to using low-flow nasal oxygen (LFNO) over high-flow nasal oxygen (HFNO) in this population. I have a number of concerns regarding the methodology used, and I disagree with the conclusion reached.

AnaesthesiaVolume 78, Issue 6 p. 688-691 Editorial Universal videolaryngoscopy: take care when crossing the Rubicon C. Lyons, Corresponding Author C. Lyons Fellow [email protected] Department of Anaesthesia, Great Ormond Street Hospital for Children, London, UK Correspondence to: C. Lyons Email: [email protected]Search for more papers by this authorB. H. Harte, B. H. Harte Consultant Department of Anaesthesia, Galway University Hospitals, Galway, IrelandSearch for more papers by this author C. Lyons, Corresponding Author C. Lyons Fellow [email protected] Department of Anaesthesia, Great Ormond Street Hospital for Children, London, UK Correspondence to: C. Lyons Email: [email protected]Search for more papers by this authorB. H. Harte, B. H. Harte Consultant Department of Anaesthesia, Galway University Hospitals, Galway, IrelandSearch for more papers by this author First published: 16 February 2023 https://doi.org/10.1111/anae.15977Citations: 9Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onEmailFacebookTwitterLinkedInRedditWechat References 1Law JA, Duggan LV, Asselin M, et al. Canadian Airway Focus Group updated consensus-based recommendations for management of the difficult airway: part 1. Difficult airway management encountered in an unconscious patient. Canadian Journal of Anesthesia 2021; 68: 1373–404. 10.1007/s12630-021-02007-0 PubMedWeb of Science®Google Scholar 2Hansel J, Rogers AM, Lewis SR, Cook TM, Smith AF. Videolaryngoscopy versus direct laryngoscopy for adults undergoing tracheal intubation. Cochrane Database of Systematic Reviews 2022; 4: CD011136. PubMedWeb of Science®Google Scholar 3Cook TM, El-Boghdadly K, McGuire B, McNarry AF, Patel A, Higgs A. Consensus guidelines for managing the airway in patients with COVID-19: guidelines from the Difficult Airway Society, the Association of Anaesthetists, the Intensive Care Society, the Faculty of Intensive Care Medicine and the Royal College of Anaesthetists. Anaesthesia 2020; 75: 785–99. 10.1111/anae.15054 CASPubMedWeb of Science®Google Scholar 4Chrimes N, Higgs A, Hagberg CA, et al. Preventing unrecognised oesophageal intubation: a consensus guideline from the Project for Universal Management of Airways and international airway societies. Anaesthesia 2022; 77: 1395–415. 10.1111/anae.15817 CASPubMedWeb of Science®Google Scholar 5 Royal College of Anaesthetists. Capnography: No Trace = Wrong Place. 2019. www.rcoa.ac.uk/safety-standards-quality/guidance-resources/capnography-no-trace-wrong-place. (accessed 28/08/2022). Google Scholar 6 Project for Universal Management of Airways. Cases of unrecognised oesophageal intubation. 2022. https://www.universalairway.org/puoi (accessed 10/11/2022). Google Scholar 7Woodall NM, Cook TM. National census of airway management techniques used for anaesthesia in the UK: first phase of the Fourth National Audit Project at the Royal College of Anaesthetists. British Journal of Anaesthesia 2011; 106: 266–71. 10.1093/bja/aeq339 CASPubMedWeb of Science®Google Scholar 8Cook TM, Woodall N, Harper J, Benger J. Major complications of airway management in the UK: results of the Fourth National Audit Project of the Royal College of Anaesthetists and the Difficult Airway Society. Part 2: intensive care and emergency departments. British Journal of Anaesthesia 2011; 106: 632–42. 10.1093/bja/aer059 CASPubMedWeb of Science®Google Scholar 9Meara JG, Leather AJM, Hagander L, et al. Global Surgery 2030: evidence and solutions for achieving health, welfare, and economic development. Lancet 2015; 386: 569–624. 10.1016/S0140-6736(15)60160-X PubMedWeb of Science®Google Scholar 10De Carvalho CC, da Silva DM, Lemos VM, et al. Videolaryngoscopy vs. direct Macintosh laryngoscopy in tracheal intubation in adults: a ranking systematic review and network meta-analysis. Anaesthesia 2022; 77: 326–38. 10.1111/anae.15626 CASPubMedWeb of Science®Google Scholar 11McElwain J, Laffey JG. Comparison of the C-MAC, Airtraq, and Macintosh laryngoscopes in patients undergoing tracheal intubation with cervical spine immobilization. British Journal of Anaesthesia 2011; 107: 258–64. 10.1093/bja/aer099 CASPubMedWeb of Science®Google Scholar 12Downey AW, Duggan LV, Law JA. A systematic review of meta-analyses comparing direct laryngoscopy with videolaryngoscopy. Canadian Journal of Anesthesia 2021; 68: 706–14. 10.1007/s12630-021-01921-7 PubMedWeb of Science®Google Scholar 13Hasegawa K, Shigemitsu K, Hagiwara Y, et al. Association between repeated intubation attempts and adverse events in emergency departments: an analysis of a multicenter prospective observational study. Annals of Emergency Medicine 2012; 60: 749–54. 10.1016/j.annemergmed.2012.04.005 PubMedWeb of Science®Google Scholar 14Frerk C, Mitchell VS, McNarry AF, et al. Difficult Airway Society 2015 guidelines for management of unanticipated difficult intubation in adults. British Journal of Anaesthesia 2015; 115: 827–48. 10.1093/bja/aev371 CASPubMedWeb of Science®Google Scholar Citing Literature Volume78, Issue6June 2023Pages 688-691 ReferencesRelatedInformation

Editor—Guy and colleagues1Guy L. Christensen R. Dodd B. et al.The effect of transnasal humidified rapid-insufflation ventilator exchange (THRIVE) versus nasal prongs on safe apnoea time in paralysed obese patients: a randomised controlled trial.Br J Anaesth. 2022; 128: 375-381Abstract Full Text Full Text PDF PubMed Scopus (9) Google Scholar recently published a randomised controlled trial investigating the effect of high-flow nasal oxygen (HFNO) at 70 L min−1 vs nasal prongs at 4 L min−1 on the safe apnoea times of patients with a BMI >35 kg m−2. Many studies have used end-tidal oxygen, arterial partial pressure of oxygen, and incidence of oxygen desaturation to measure the efficacy of HFNO. In this case, the authors are to be commended for selecting time to oxygen desaturation to ≤95% as the primary outcome as this reflects the most direct measure of oxygenation reserves. However, the study has a major limitation: use of a 360 s cut-off for apnoea time determination. As apnoea time is lengthened, the contribution of pre-oxygenation reserves diminishes and the impact of apnoeic oxygenation, if any, becomes clearer. Unfortunately, this study terminated for one-third of patients during a key period of observation despite them being adequately oxygenated. Based on the preceding pattern of desaturation and rate of PaO2 decline, the 10 participants in the HFNO arm remaining at 360 s of apnoea were more likely to exhibit a longer time to desaturation than the four participants remaining in the low-flow nasal oxygen arm. However, by applying a cut-off of 360 s, all 14 participants became equal in their apnoea times. This cut-off therefore makes data for the primary outcome difficult, if not impossible, to interpret. The statement that ‘our results suggest a clinical effect in prolonging the time to desaturation’ but that they are also ‘statistically inconclusive’ reflects this difficulty. The reason given for a 360-s endpoint was to ‘ensure patient safety’, but this is not expanded upon by the authors. The main physiological changes during apnoea are a declining PaO2 and increasing PaCO2 (with associated acidaemia). Hypoxaemia does not go unrecognised because of pulse oximetry, whereas the degree of hypercarbia after 6 min of apnoea, as demonstrated by data from this study and others,2Gustafsson I.M. Lodenius A. Tunelli J. Ullman J. Jonsson Fagerlund M. Apnoeic oxygenation in adults under general anaesthesia using Transnasal Humidified Rapid-Insufflation Ventilatory Exchange (THRIVE) — a physiological study.Br J Anaesth. 2017; 118: 610-617Abstract Full Text Full Text PDF PubMed Scopus (139) Google Scholar,3Lyons C. Callaghan M. Apnoeic oxygenation with high-flow nasal oxygen for laryngeal surgery: a case series.Anaesthesia. 2017; 72: 1379-1387Crossref PubMed Scopus (54) Google Scholar would not have proved problematic. The durations of pre-oxygenation and use of additional airway management before the commencement of apnoeic oxygenation are not documented. It is also unclear why the PEEP values selected during manual ventilation were left to the discretion of the anaesthetist. Given these factors, attainment of an end-tidal oxygen of 90% does not necessarily mean that both groups received equal oxygenation before the point of commencing nasal oxygen administration. Gaining knowledge from clinical trials involving patients with easily managed airways is valuable but applying that knowledge to patients with difficult airways is fraught with limitations. For example, difficult bag-mask ventilation and difficult laryngoscopy can reflect loss of upper airway patency, which would also render HFNO ineffective. In this study, bag-mask ventilation and laryngoscopy were easy for all included patients, meaning the benefits of HFNO were arguably non-existent. In addition, the scenario in question was contrived (airway management is not usually postponed for 6 min after successful face mask ventilation), which is potentially valuable in terms of standardisation of methods and data collection but does not reflect routine care of future patients to whom this knowledge might be applied. With respect to terminology, the authors refer to transnasal humidified rapid-insufflation ventilatory exchange (THRIVE) as a specific subset of HFNO; however, this term has merely reflected HFNO use during apnoea. The study references supporting evidence that THRIVE results in carbon dioxide clearance in spontaneously breathing patients.4Booth A.W.G. Vidhani K. Lee P.K. et al.The effect of highflow nasal oxygen on carbon dioxide accumulation in apneic or spontaneously breathing adults during airway surgery: a randomized-controlled trial.Anesth Analg. 2021; 133: 133-141Crossref PubMed Scopus (18) Google Scholar However, this terminology is not compatible with spontaneous respiration; it refers only to a condition of apnoea. There are uncertainties surrounding the potential of THRIVE to achieve ‘ventilatory exchange’ (i.e. carbon dioxide clearance), which has not yet been demonstrated in randomised controlled trials. In addition, THRIVE has been combined with use of the Optiflow device (Fisher & Paykel Healthcare, Auckland, New Zealand) for trademarking purposes but other HFNO devices function in a similar manner. In light of these factors, use of the term ‘THRIVE’ should be restricted, or even abandoned, in clinical practice and academic writings. The author declares no conflict of interest. None.

Abstract Patients undergoing oromaxillofacial and head and neck surgery can have pathologies that threaten the reliability of oxygen delivery under anaesthesia. Airway management requires a patient-specific and procedure-specific focus, working within the skillset of the anaesthesia and surgical services of the day. This chapter on difficult airway management focuses upon airway assessment and the formation of an airway management plan. Core airway management techniques are discussed, including bag mask ventilation, use of supraglottic airway devices, and laryngoscopy by direct and video-based means. The importance of positioning, preoxygenation, and neuromuscular blockade is explained. Awake airway management techniques (awake fibreoptic intubation, awake videolaryngoscopy, and awake tracheostomy) are discussed, being viewed as essential components of anaesthetists’ armamentarium. Airway management for maxillomandibular fixation is afforded special attention due to the requirement for specific knowledge and skills. The extubation process is explored, with pre-emptive and rescue techniques that may reduce the likelihood of airway compromise during this period identified. Finally, the contribution of human factors to difficult airway management is considered, with task fixation and cognitive overload highlighted as potential threats that must be overcome by anaesthetists in order to prioritize reliable patient oxygenation.

Abstract Patients undergoing oromaxillofacial and head and neck surgery can have pathologies that threaten the reliability of oxygen delivery under anaesthesia. Airway management requires a patient-specific and procedure-specific focus, working within the skillset of the anaesthesia and surgical services of the day. This chapter on difficult airway management focuses upon airway assessment and the formation of an airway management plan. Core airway management techniques are discussed, including bag mask ventilation, use of supraglottic airway devices, and laryngoscopy by direct and video-based means. The importance of positioning, preoxygenation, and neuromuscular blockade is explained. Awake airway management techniques (awake fibreoptic intubation, awake videolaryngoscopy, and awake tracheostomy) are discussed, being viewed as essential components of anaesthetists’ armamentarium. Airway management for maxillomandibular fixation is afforded special attention due to the requirement for specific knowledge and skills. The extubation process is explored, with pre-emptive and rescue techniques that may reduce the likelihood of airway compromise during this period identified. Finally, the contribution of human factors to difficult airway management is considered, with task fixation and cognitive overload highlighted as potential threats that must be overcome by anaesthetists in order to prioritize reliable patient oxygenation.

AnaesthesiaVolume 77, Issue 2 p. 132-134 Editorial Hypotension – what we say and what we do C. Lyons, C. Lyons Specialist Trainee Department of Anaesthesia, Galway University Hospitals, Galway, IrelandSearch for more papers by this authorI. K. Moppett, I. K. Moppett Professor @IainMoppett Anaesthesia and Critical Care Section, Academic Unit of Injury, Inflammation and Recovery Science, Queen’s Medical Centre, University of Nottingham, Nottingham, UKSearch for more papers by this author C. Lyons, C. Lyons Specialist Trainee Department of Anaesthesia, Galway University Hospitals, Galway, IrelandSearch for more papers by this authorI. K. Moppett, I. K. Moppett Professor @IainMoppett Anaesthesia and Critical Care Section, Academic Unit of Injury, Inflammation and Recovery Science, Queen’s Medical Centre, University of Nottingham, Nottingham, UKSearch for more papers by this author First published: 20 September 2021 https://doi.org/10.1111/anae.15584 Correspondence to: C. Lyons Email: craigmacliathain@gmail.com This editorial accompanies articles by Wickham et al., 77: 153–63 and Kluger et al., 77: 164–74 Anaesthesia 2021 Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume77, Issue2February 2022Pages 132-134 RelatedInformation

High-flow nasal oxygen used before and during apnoea prolongs time to desaturation at induction of anaesthesia. It is unclear how much oxygenation before apnoea prolongs this time. We randomly allocated 84 participants to 3 minutes of pre-oxygenation by one of three methods: 15 l.min-1 by facemask; 50 l.min-1 by high-flow nasal cannulae only; or 50 l.min-1 by high-flow nasal cannulae plus 15 l.min-1 by mouthpiece. We then anaesthetised and intubated the trachea of 79 participants and waited for oxygen saturation to fall to 92%. Median (IQR [range]) times to desaturate to 92% after pre-oxygenation with facemask oxygen, high-flow nasal oxygen only and high-flow nasal oxygen with mouthpiece, were: 309 (208-417 [107-544]) s; 344 (250-393 [194-585]) s; and 386 (328-498 [182-852]) s, respectively, p = 0.014. Time to desaturation after facemask pre-oxygenation was shorter than after combined nasal and mouthpiece pre-oxygenation, p = 0.006. We could not statistically distinguish high-flow nasal oxygen without mouthpiece from the other two groups for this outcome. Median (IQR [range]) arterial oxygen partial pressure after 3 minutes of pre-oxygenation by facemask, nasal cannulae and nasal cannulae plus mouthpiece, was: 49 (36-61 [24-66]) kPa; 57 (48-62 [30-69]) kPa; and 61 (55-64 [36-72]) kPa, respectively, p = 0.003. Oxygen partial pressure after 3 minutes of pre-oxygenation with nasal and mouthpiece combination was greater than after facemask pre-oxygenation, p = 0.002, and after high-flow nasal oxygen alone, p = 0.016. We did not reject the null hypothesis for the pairwise comparison of facemask pre-oxygenation and high-flow nasal pre-oxygenation, p = 0.14.