Quantifying hospital environmental ventilation using carbon dioxide monitoring - a multicentre study.

The COVID-19 pandemic has highlighted the importance of environmental ventilation in reducing airborne pathogen transmission. Carbon dioxide monitoring is recommended in the community to ensure adequate ventilation. Dynamic measurements of ventilation quantifying human exhaled waste gas accumulation are not conducted routinely in hospitals. Instead, environmental ventilation is allocated using static hourly air change rates. These vary according to the degree of perceived hazard, with the highest change rates reserved for locations where aerosol-generating procedures are performed, where medical/anaesthetic gases are used and where a small number of high-risk infective or immunocompromised patients may be isolated to reduce cross-infection. We aimed to quantify the quality and distribution of ventilation in hospital by measuring carbon dioxide levels in a two-phased prospective observational study. First, under controlled conditions, we validated our method and the relationship between human occupancy, ventilation and carbon dioxide levels using non-dispersive infrared carbon dioxide monitors. We then assessed ventilation quality in patient-occupied (clinical) and staff break and office (non-clinical) areas across two hospitals in Scotland. We selected acute medical and respiratory wards in which patients with COVID-19 are cared for routinely, as well as ICUs and operating theatres where aerosol-generating procedures  are performed routinely. Between November and December 2022, 127,680 carbon dioxide measurements were obtained across 32 areas over 8 weeks. Carbon dioxide levels breached the 800 ppm threshold for 14% of the time in non-clinical areas vs. 7% in clinical areas (p < 0.001). In non-clinical areas, carbon dioxide levels were > 800 ppm for 20% of the time in both ICUs and wards, vs. 1% in operating theatres (p < 0.001). In clinical areas, carbon dioxide was > 800 ppm for 16% of the time in wards, vs. 0% in ICUs and operating theatres (p < 0.001). We conclude that staff break, office and clinical areas on acute medical and respiratory wards frequently had inadequate ventilation, potentially increasing the risks of airborne pathogen transmission to staff and patients. Conversely, ventilation was consistently high in the ICU and operating theatre clinical environments. Carbon dioxide monitoring could be used to measure and guide improvements in hospital ventilation.

Analysis of a national difficult airway database.

Difficult airway management continues to adversely affect patient care and clinical outcomes and is poorly predicted. Previous difficult airway management is the most accurate predictor of future difficulty. The Difficult Airway Society initiated a national airway database to allow clinicians to access details of previous difficult airway episodes in patients issued with a difficult airway alert card. We aimed to analyse this database, reporting patient characteristics, airway management and patient outcomes. We included all living adult patients reported in the first 5 years of the database (n = 675). Clinical airway assessment was reported in 634 (94%) patients, with three or more parameters assessed in 488 (72%). A history of difficult airway was known in 136 (20%) patients and difficult airway management was anticipated in 391 (58%). In all, 75 (11%) patients had an airway-related critical incident, with 1 in 29 being awoken from anaesthesia, 1 in 34 requiring unplanned or prolonged stay in the intensive care unit and 1 in 225 needing an emergency front-of-neck airway or had a cardiac arrest/peri-arrest episode. Airway-related critical incidents were associated with out-of-hours airway management, but no other associations were apparent. Our data report the first analysis of a national difficult airway database, finding that unanticipated difficult airway management continues to occur despite airway assessment, and the rate of critical incidents in this cohort of patients is high. This database has the potential to improve airway management for patients in the future.

Transnasal humidified rapid-insufflation ventilatory exchange ('THRIVE') in the coronavirus disease 2019 pandemic.

BACKGROUND: Since the start of the coronavirus disease 2019 pandemic, transnasal humidified rapid-insufflation ventilatory exchange ('THRIVE') has been classified as a high-risk aerosol-generating procedure and is strongly discouraged, despite a lack of conclusive evidence on its safety. METHODS: This study aimed to investigate the safety of transnasal humidified rapid-insufflation ventilatory exchange usage and its impact on staff members. A prospective study was conducted on all transnasal humidified rapid-insufflation ventilatory exchange cases performed in our unit between March and July 2020. RESULTS: During the study period, 18 patients with a variety of airway pathologies were successfully managed with transnasal humidified rapid-insufflation ventilatory exchange. For each case, 7-10 staff members were present. Appropriate personal protective equipment protocols were strictly implemented and adhered to. None of the staff involved reported symptoms or tested positive for coronavirus disease 2019, up to at least a month following their exposure to transnasal humidified rapid-insufflation ventilatory exchange. CONCLUSION: With strictly correct personal protective equipment use, transnasal humidified rapid-insufflation ventilatory exchange can be safely employed for carefully selected patients in the current pandemic, without jeopardising the health and safety of the ENT and anaesthetic workforce.

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.

Severe acute respiratory syndrome-corona virus-2, which causes coronavirus disease 2019 (COVID-19), is highly contagious. Airway management of patients with COVID-19 is high risk to staff and patients. We aimed to develop principles for airway management of patients with COVID-19 to encourage safe, accurate and swift performance. This consensus statement has been brought together at short notice to advise on airway management for patients with COVID-19, drawing on published literature and immediately available information from clinicians and experts. Recommendations on the prevention of contamination of healthcare workers, the choice of staff involved in airway management, the training required and the selection of equipment are discussed. The fundamental principles of airway management in these settings are described for: emergency tracheal intubation; predicted or unexpected difficult tracheal intubation; cardiac arrest; anaesthetic care; and tracheal extubation. We provide figures to support clinicians in safe airway management of patients with COVID-19. The advice in this document is designed to be adapted in line with local workplace policies.

Use of transnasal humidified rapid-insufflation ventilatory exchange (THRIVE) to facilitate the management of subglottic stenosis in pregnancy.

Subglottic stenosis is a rare condition. Diagnosis is often delayed as symptoms are attributed to other causes, such as asthma. This problem may be compounded in pregnancy when dyspnoea may be attributed to normal physiological changes. In respiratory compromise, surgical intervention may be required and airway management is challenging as endotracheal intubation may be traumatic or, in severe cases, impossible. Transnasal humidified rapid-insufflation ventilatory exchange (THRIVE) is a novel open-airway apnoeic technique using high-flow nasal oxygen. It does not expose the patient to the risks of jet ventilation, nor does it require the placement of an airway device to effectively oxygenate the patient. In pregnancy, elevation of maternal carbon dioxide is of particular concern as it may result in a worsening fetal acidosis. While THRIVE has been shown to provide some clearance of carbon dioxide, a patent airway is required for it to function effectively. In this case report we describe the management of a pregnant patient who underwent balloon dilatation for severe subglottic stenosis at 23 weeks' gestation using THRIVE and we summarise the evidence supporting the use of this new technique in pregnant women.

Difficult Airway Society guidelines for awake tracheal intubation (ATI) in adults.

Awake tracheal intubation has a high success rate and a favourable safety profile but is underused in cases of anticipated difficult airway management. These guidelines are a comprehensive document to support decision making, preparation and practical performance of awake tracheal intubation. We performed a systematic review of the literature seeking all of the available evidence for each element of awake tracheal intubation in order to make recommendations. In the absence of high-quality evidence, expert consensus and a Delphi study were used to formulate recommendations. We highlight key areas of awake tracheal intubation in which specific recommendations were made, which included: indications; procedural setup; checklists; oxygenation; airway topicalisation; sedation; verification of tracheal tube position; complications; management of unsuccessful awake tracheal intubation; post-tracheal intubation management; consent; and training. We recognise that there are a range of techniques and regimens that may be effective and one such example technique is included. Breaking down the key practical elements of awake tracheal intubation into sedation, topicalisation, oxygenation and performance might help practitioners to plan, perform and address complications. These guidelines aim to support clinical practice and help lower the threshold for performing awake tracheal intubation when indicated.

The evolution of airway management - new concepts and conflicts with traditional practice.

In the last 25 yr, there have been several advances in the safe management of the airway. Videolaryngoscopes and supraglottic airways, now in routine use by new trainees in anaesthesia, have had their genesis in the recent past. The 4th National Audit Project of the Royal College of Anaesthetists and the Difficult Airway Society published in 2011 a seminal report that has influenced airway management worldwide . Understanding how the report's recommendations were constructed and how clinical guidelines compliment rather than contradict them is important in understanding the tenets of safe airway management. Over the last 25 yr there has been an increasing understanding of the effects of human factors in anaesthesiology: we may not perform in a predictable or optimal manner when faced with unusual and threatening challenges. The place of cricoid pressure in anaesthetic practice has also evolved. Current recommendations are that it be applied, but it should be released rapidly should airway difficulty be encountered. The need to prevent hypoxaemia by preoxygenation has long been recognized, but the role of high-flow nasal oxygen in anaesthesia is now being realized and developed. Clinicians must decide how novel therapies and long-standing practices are adapted to best meet the needs of our patients and prevent harm during airway management.

The impact of didactic read-aloud action cards on the performance of cannula cricothyroidotomy in a simulated 'can't intubate can't oxygenate' scenario.

Significant benefits have been demonstrated with the use of peri-operative checklists. We assessed whether a read-aloud didactic action card would improve performance of cannula cricothyroidotomy in a simulated 'can't intubate, can't oxygenate' scenario. A 17-step action card was devised by an expert panel. Participants in their first 4 years of anaesthetic training were randomly assigned into 'no-card' or 'card' groups. Scenarios were video-recorded for analysis. Fifty-three participants (27 no-card and 26 card) completed the scenario. The number of steps omitted was mean (SD) 6.7 (2.0) in the no-card group vs. 0.3 (0.5); p < 0.001 in the card group, but the no-card group was faster to oxygenation by mean (95% CI) 35.4 (6.6-64.2) s. The Kappa statistic was 0.84 (0.73-0.95). Our study demonstrated that action cards are beneficial in achieving successful front-of-neck access using a cannula cricothyroidotomy technique. Further investigation is required to determine this tool's effectiveness in other front-of-neck access situations, and its role in teaching or clinical management.

Difficult Airway Society 2015 guidelines for management of unanticipated difficult intubation in adults.

These guidelines provide a strategy to manage unanticipated difficulty with tracheal intubation. They are founded on published evidence. Where evidence is lacking, they have been directed by feedback from members of the Difficult Airway Society and based on expert opinion. These guidelines have been informed by advances in the understanding of crisis management; they emphasize the recognition and declaration of difficulty during airway management. A simplified, single algorithm now covers unanticipated difficulties in both routine intubation and rapid sequence induction. Planning for failed intubation should form part of the pre-induction briefing, particularly for urgent surgery. Emphasis is placed on assessment, preparation, positioning, preoxygenation, maintenance of oxygenation, and minimizing trauma from airway interventions. It is recommended that the number of airway interventions are limited, and blind techniques using a bougie or through supraglottic airway devices have been superseded by video- or fibre-optically guided intubation. If tracheal intubation fails, supraglottic airway devices are recommended to provide a route for oxygenation while reviewing how to proceed. Second-generation devices have advantages and are recommended. When both tracheal intubation and supraglottic airway device insertion have failed, waking the patient is the default option. If at this stage, face-mask oxygenation is impossible in the presence of muscle relaxation, cricothyroidotomy should follow immediately. Scalpel cricothyroidotomy is recommended as the preferred rescue technique and should be practised by all anaesthetists. The plans outlined are designed to be simple and easy to follow. They should be regularly rehearsed and made familiar to the whole theatre team.

Safety in the emergency situation: the airway--a theatre team approach.

Managing an expected or unanticipated difficult airway can result in morbidity and even mortality (Cook et al 2011). These scenarios place considerable demands on the anaesthetic team and require the wider support of theatre staff. It is crucial that the perioperative team is adequately prepared for these time-critical emergencies in order to prevent avoidable patient harm. This article introduces the topic and discusses the core knowledge and skills required of the perioperative team.

Difficult airway communication between anaesthetists and general practitioners.

BACKGROUND AND AIMS: Advance warning of patients who are difficult to intubate may prevent an airway catastrophe but relies on effective communication between specialties. Anaesthetists aim to inform general practitioners whenever a difficult airway is encountered and expect general practitioners to include this information in subsequent referrals. We investigated how anaesthetists communicated with general practitioners, their knowledge of the Read Code (used by general practitioner computer systems) for difficult tracheal intubation, and how likely general practitioners were to pass the information on. METHODS AND RESULTS: We surveyed 631 consultant anaesthetists and 217 general practitioners. We found only 125 (20%) anaesthetists consistently wrote difficult airway letters to general practitioners. Only 20 (3%) knew the Read Code for difficult intubation (SP2y3), although 454 (72%) thought it to be useful. Most general practitioners (212, 98%) thought airway information to be important, but only half receiving a difficult airway communication forwarded it on. General practitioners recommended including the Read Code SP2y3 and labelling it 'high priority', ensuring that 'Difficult Tracheal Intubation' would be listed in the Emergency Care Summary generated for hospital referrals. CONCLUSION: Communication between anaesthetists and general practitioners is currently poor, but could be improved by simplifying difficult airway letters and including the SP2y3 code and a statement of priority.