Peri-operative cardiac arrest: epidemiology and clinical features of patients analysed in the 7th National Audit Project of the Royal College of Anaesthetists.

The 7th National Audit Project of the Royal College of Anaesthetists studied peri-operative cardiac arrest in the UK, a topic of importance to patients, anaesthetists and surgeons. Here we report the results of the 12-month registry, from 16 June 2021 to 15 June 2022, focusing on epidemiology and clinical features. We reviewed 881 cases of peri-operative cardiac arrest, giving an incidence of 3 in 10,000 anaesthetics (95%CI 3.0-3.5 per 10,000). Incidence varied with patient and surgical factors. Compared with denominator survey activity, patients with cardiac arrest: included more males (56% vs. 42%); were older (median (IQR) age 60.5 (40.5-80.5) vs. 50.5 (30.5-70.5) y), although the age distribution was bimodal, with infants and patients aged > 66 y overrepresented; and were notably more comorbid (73% ASA physical status 3-5 vs. 27% ASA physical status 1-2). The surgical case-mix included more weekend (14% vs. 11%), out-of-hours (19% vs. 10%), non-elective (65% vs. 30%) and major/complex cases (60% vs. 28%). Cardiac arrest was most prevalent in orthopaedic trauma (12%), lower gastrointestinal surgery (10%), cardiac surgery (9%), vascular surgery (8%) and interventional cardiology (6%). Specialities with the highest proportion of cases relative to denominator activity were: cardiac surgery (9% vs. 1%); cardiology (8% vs. 1%); and vascular surgery (8% vs. 2%). The most common causes of cardiac arrest were: major haemorrhage (17%); bradyarrhythmia (9%); and cardiac ischaemia (7%). Patient factors were judged a key cause of cardiac arrest in 82% of cases, anaesthesia in 40% and surgery in 35%.

The incidence of potentially serious complications during non-obstetric anaesthetic practice in the United Kingdom: an analysis from the 7th National Audit Project (NAP7) activity survey.

Complications and critical incidents arising during anaesthesia due to patient, surgical or anaesthetic factors, may cause harm themselves or progress to more severe events, including cardiac arrest or death. As part of the 7th National Audit Project of the Royal College of Anaesthetists, we studied a prospective national cohort of unselected patients. Anaesthetists recorded anonymous details of all cases undertaken over 4 days at their site through an online survey. Of 416 hospital sites invited to participate, 352 (85%) completed the survey. Among 24,172 cases, 1922 discrete potentially serious complications were reported during 1337 (6%) cases. Obstetric cases had a high reported major haemorrhage rate and were excluded from further analysis. Of 20,996 non-obstetric cases, 1705 complications were reported during 1150 (5%) cases. Circulatory events accounted for most complications (616, 36%), followed by airway (418, 25%), metabolic (264, 15%), breathing (259, 15%), and neurological (41, 2%) events. A single complication was reported in 851 (4%) cases, two complications in 166 (1%) cases and three or more complications in 133 (1%) cases. In non-obstetric elective surgery, all complications were 'uncommon' (10-100 per 10,000 cases). Emergency (urgent and immediate priority) surgery accounted for 3454 (16%) of non-obstetric cases but 714 (42%) of complications with severe hypotension, major haemorrhage, severe arrhythmias, septic shock, significant acidosis and electrolyte disturbances all being 'common' (100-1000 per 10,000 cases). Based on univariate analysis, complications were associated with: younger age; higher ASA physical status; male sex; increased frailty; urgency and extent of surgery; day of the week; and time of day. These data represent the rates of potentially serious complications during routine anaesthesia care and may be valuable for risk assessment and patient consent.

Peri-operative cardiac arrest: management and outcomes of patients analysed in the 7th National Audit Project of the Royal College of Anaesthetists.

The 7th National Audit Project of the Royal College of Anaesthetists studied peri-operative cardiac arrest in the UK, a topic of importance to patients, anaesthetists and surgeons. We report the results of the 12-month registry phase, from 16 June 2021 to 15 June 2022, focusing on management and outcomes. Among 881 cases of peri-operative cardiac arrest, the initial rhythm was non-shockable in 723 (82%) cases, most commonly pulseless electrical activity. There were 665 (75%) patients who survived the initial event and 384 (52%) who survived to hospital discharge. A favourable functional outcome (based on modified Rankin Scale score) was reported for 249 (88%) survivors. Outcomes varied according to arrest rhythm. The highest rates of survival were seen for bradycardic cardiac arrests with 111 (86%) patients surviving the initial event and 77 (60%) patients surviving the hospital episode. The lowest survival rates were seen for patients with pulseless electrical activity, with 312 (68%) surviving the initial episode and 156 (34%) surviving to hospital discharge. Survival to hospital discharge was worse in patients at the extremes of age with 76 (40%) patients aged > 75 y and 9 (45%) neonates surviving. Hospital survival was also associated with surgical priority, with 175 (88%) elective patients and 176 (37%) non-elective patients surviving to discharge. Outcomes varied with the cause of cardiac arrest, with lower initial survival rates for pulmonary embolism (5, 31%) and bone cement implantation syndrome (9, 45%), and hospital survival of < 25% for pulmonary embolism (0), septic shock (13, 24%) and significant hyperkalaemia (1, 20%). Overall care was rated good in 464 (53%) cases, and 18 (2%) cases had overall care rated as poor. Poor care elements were present in a further 245 (28%) cases. Care before cardiac arrest was the phase most frequently rated as poor (92, 11%) with elements of poor care identified in another 186 (21%) cases. These results describe the management and outcomes of peri-operative cardiac arrest in UK practice for the first time.

The 7th National Audit Project (NAP7) baseline survey of individual anaesthetists: preparedness for and experiences of peri-operative cardiac arrest.

The Royal College of Anaesthetists' 7th National Audit Project baseline survey assessed knowledge, attitudes, practices and experiences of peri-operative cardiac arrests among UK anaesthetists and Anaesthesia Associates. We received 10,746 responses, representing a 71% response rate. In-date training in adult and paediatric advanced life support was reported by 9646 (90%) and 7125 (66%) anaesthetists, respectively. There were 8994 (84%) respondents who were confident in leading a peri-operative cardiac arrest, with males more confident than females, but only 5985 (56%) were confident in leading a debrief and 7340 (68%) communicating with next of kin. In the previous two years, 4806 (46%) respondents had managed at least one peri-operative cardiac arrest, of which 321 (7%) and 189 (4%) of these events involved a child or an obstetric patient, respectively. Respondents estimated the most common causes of peri-operative cardiac arrest to be hypovolaemia, hypoxaemia and cardiac ischaemia, with haemorrhage coming fifth. However, the most common reported causes for the most recently attended peri-operative cardiac arrest were haemorrhage; (927, 20%); anaphylaxis (474, 10%); and cardiac ischaemia (397, 9%). Operating lists or shifts were paused or stopped after 1330 (39%) cardiac arrests and 1693 (38%) respondents attended a debrief, with 'hot' debriefs most common. Informal wellbeing support was relatively common (2458, 56%) and formal support was uncommon (472, 11%). An impact on future care delivery was reported by 196 (4%) anaesthetists, most commonly a negative psychological impact. Management of a peri-operative cardiac arrest during their career was reported by 8654 (85%) respondents. The overall impact on professional life was more often judged positive (2630, 30%) than negative (1961, 23%), but impact on personal life was more often negative.

Organisation of UK hospitals and anaesthetic departments in the treatment of peri-operative cardiac arrest: an analysis from the 7th National Audit Project (NAP7) local co-ordinator baseline survey.

We report the results of the Royal College of Anaesthetists' 7th National Audit Project organisational baseline survey sent to every NHS anaesthetic department in the UK to assess preparedness for treating peri-operative cardiac arrest. We received 199 responses from 277 UK anaesthetic departments, representing a 72% response rate. Adult and paediatric anaesthetic care was provided by 188 (95%) and 165 (84%) hospitals, respectively. There was no paediatric intensive care unit on-site in 144 (87%) hospitals caring for children, meaning transfer of critically ill children is required. Remote site anaesthesia is provided in 182 (92%) departments. There was a departmental resuscitation lead in 113 (58%) departments, wellbeing lead in 106 (54%) and departmental staff wellbeing policy in 81 (42%). A defibrillator was present in every operating theatre suite and in all paediatric anaesthesia locations in 193 (99%) and 149 (97%) departments, respectively. Advanced airway equipment was not available in: every theatre suite in 13 (7%) departments; all remote locations in 103 (57%) departments; and all paediatric anaesthesia locations in 23 (15%) departments. Anaesthetic rooms were the default location for induction of anaesthesia in adults and children in 148 (79%) and 121 (79%) departments, respectively. Annual updates in chest compressions and in defibrillation were available in 149 (76%) and 130 (67%) departments, respectively. Following a peri-operative cardiac arrest, debriefing and peer support programmes were available in 154 (79%) and 57 (29%) departments, respectively. While it is likely many UK hospitals are very well prepared to treat anaesthetic emergencies including cardiac arrest, the survey suggests this is not universal.

Patient characteristics, anaesthetic workload and techniques in the UK: an analysis from the 7th National Audit Project (NAP7) activity survey.

Detailed contemporary knowledge of the characteristics of the surgical population, national anaesthetic workload, anaesthetic techniques and behaviours are essential to monitor productivity, inform policy and direct research themes. Every 3-4 years, the Royal College of Anaesthetists, as part of its National Audit Projects (NAP), performs a snapshot activity survey in all UK hospitals delivering anaesthesia, collecting patient-level encounter data from all cases under the care of an anaesthetist. During November 2021, as part of NAP7, anaesthetists recorded details of all cases undertaken over 4 days at their site through an online survey capturing anonymous patient characteristics and anaesthetic details. Of 416 hospital sites invited to participate, 352 (85%) completed the activity survey. From these, 24,177 reports were returned, of which 24,172 (99%) were included in the final dataset. The work patterns by day of the week, time of day and surgical specialty were similar to previous NAP activity surveys. However, in non-obstetric patients, between NAP5 (2013) and NAP7 (2021) activity surveys, the estimated median age of patients increased by 2.3 years from median (IQR) of 50.5 (28.4-69.1) to 52.8 (32.1-69.2) years. The median (IQR) BMI increased from 24.9 (21.5-29.5) to 26.7 (22.3-31.7) kg.m-2 . The proportion of patients who scored as ASA physical status 1 decreased from 37% in NAP5 to 24% in NAP7. The use of total intravenous anaesthesia increased from 8% of general anaesthesia cases to 26% between NAP5 and NAP7. Some changes may reflect the impact of the COVID-19 pandemic on the anaesthetic population, though patients with confirmed COVID-19 accounted for only 149 (1%) cases. These data show a rising burden of age, obesity and comorbidity in patients requiring anaesthesia care, likely to impact UK peri-operative services significantly.

Methods of the 7th National Audit Project (NAP7) of the Royal College of Anaesthetists: peri-operative cardiac arrest.

Cardiac arrest in the peri-operative period is rare but associated with significant morbidity and mortality. Current reporting systems do not capture many such events, so there is an incomplete understanding of incidence and outcomes. As peri-operative cardiac arrest is rare, many hospitals may only see a small number of cases over long periods, and anaesthetists may not be involved in such cases for years. Therefore, a large-scale prospective cohort is needed to gain a deep understanding of events leading up to cardiac arrest, management of the arrest itself and patient outcomes. Consequently, the Royal College of Anaesthetists chose peri-operative cardiac arrest as the 7th National Audit Project topic. The study was open to all UK hospitals offering anaesthetic services and had a three-part design. First, baseline surveys of all anaesthetic departments and anaesthetists in the UK, examining respondents' prior peri-operative cardiac arrest experience, resuscitation training and local departmental preparedness. Second, an activity survey to record anonymised details of all anaesthetic activity in each site over 4 days, enabling national estimates of annual anaesthetic activity, complexity and complication rates. Third, a case registry of all instances of peri-operative cardiac arrest in the UK, reported confidentially and anonymously, over 1 year starting 16 June 2021, followed by expert review using a structured process to minimise bias. The definition of peri-operative cardiac arrest was the delivery of five or more chest compressions and/or defibrillation in a patient having a procedure under the care of an anaesthetist. The peri-operative period began with the World Health Organization 'sign-in' checklist or first hands-on contact with the patient and ended either 24 h after the patient handover (e.g. to the recovery room or intensive care unit) or at discharge if this occured earlier than 24 h. These components described the epidemiology of peri-operative cardiac arrest in the UK and provide a basis for developing guidelines and interventional studies.

pRotective vEntilation with veno-venouS lung assisT in respiratory failure: A protocol for a multicentre randomised controlled trial of extracorporeal carbon dioxide removal in patients with acute hypoxaemic respiratory failure.

One of the few interventions to demonstrate improved outcomes for acute hypoxaemic respiratory failure is reducing tidal volumes when using mechanical ventilation, often termed lung protective ventilation. Veno-venous extracorporeal carbon dioxide removal (vv-ECCO2R) can facilitate reducing tidal volumes. pRotective vEntilation with veno-venouS lung assisT (REST) is a randomised, allocation concealed, controlled, open, multicentre pragmatic trial to determine the clinical and cost-effectiveness of lower tidal volume mechanical ventilation facilitated by vv-ECCO2R in patients with acute hypoxaemic respiratory failure. Patients requiring intubation and mechanical ventilation for acute hypoxaemic respiratory failure will be randomly allocated to receive either vv-ECCO2R and lower tidal volume mechanical ventilation or standard care with stratification by recruitment centre. There is a need for a large randomised controlled trial to establish whether vv-ECCO2R in acute hypoxaemic respiratory failure can allow the use of a more protective lung ventilation strategy and is associated with improved patient outcomes.

Extracorporeal carbon dioxide removal to "protect" the lung.

The case histories are presented of three adults who had severe hypercapnic acidosis despite mechanical ventilation with what were considered to be injurious tidal volumes and airway pressures. The use of a percutaneously inserted arteriovenous extracorporeal carbon dioxide removal (AV-ECCO(2)R) device facilitated a dramatic reduction in the amount of ventilatory support required, achieving a "lung-protective" level. Two patients survived to hospital discharge. One patient died after it became apparent that her late-stage interstitial lung disease was unresponsive to immunosuppression. AV-ECCO(2)R may be a useful strategy in facilitating lung-protective ventilation.

Treatment of pulmonary hypertension in the general adult intensive care unit: a role for oral sildenafil?

Use of inhaled nitric oxide for treatment of pulmonary hypertension in adult critical illness is limited by its mode of delivery and high costs, prompting evaluation of alternative therapies. We report the use of oral sildenafil in a patient with severe secondary pulmonary hypertension and right ventricular dysfunction. Following reduction in mean pulmonary artery pressure and pulmonary vascular resistance with inhaled nitric oxide, crossover to sildenafil therapy maintained control of pulmonary hypertension, facilitating discontinuation of respiratory and cardiovascular organ support. The relative pulmonary vascular specificity of oral sildenafil, and its low cost, makes it an attractive therapeutic alternative to inhaled nitric oxide, and warrants further study.

Mechanical ventilation in acute respiratory distress syndrome.

The acute respiratory distress syndrome occurs commonly in critical care. There is an increasing volume of clinical and experimental evidence that poor ventilatory technique that is injurious to the lungs can propagate the systemic inflammatory response and adversely affect mortality. Many ventilatory techniques have been hypothesized to 'protect' the lungs during mechanical ventilation, including tidal volume limitation, high positive end-expiratory pressure, pressure-controlled inverse ratio ventilation, and prone positioning. Experimental techniques include liquid ventilation, surfactant administration and extracorporeal gas exchange. Despite excellent rationale for their use, few techniques, apart from tidal volume limitation, have been shown to improve survival in randomized controlled trials.

Reduced mortality in association with the acute respiratory distress syndrome (ARDS).

BACKGROUND: A study was undertaken to investigate possible reductions in mortality and/or changes in outcome predictive factors in patients with the acute respiratory distress syndrome (ARDS) managed in a single centre. METHODS: The study was a prospective observational cohort study of two patient populations with ARDS. Group 1 comprised 41 patients enrolled between May 1990 and April 1993, and group 2 consisted of 78 patients enrolled between June 1993 and March 1997. The end points of the study were mortality and various factors predictive of death. RESULTS: There was a marked reduction in mortality between groups 1 and 2 (66% versus 34%; relative risk 1.77; CI 1.23 to 2.55). There were no significant differences between the groups in terms of age (40.6 (3.3) versus 45.5 (2.2) years), APACHE score (14.5 (0.72) versus 13.6 (0.1)), lung injury score (2.95 (0.07) versus 2.8 (0.1)), incidence of multi-organ failure (29% versus 32%), incidence of sepsis (31% versus 39%), or PaO2/FIO2 (kPa) ratio (11.8 (0.67) versus 12.0 (0.6)). There was a significantly lower proportion of men in group 1 (51% versus 74%). The case mix of the two groups was closely matched: following elective surgery 48% versus 48%, trauma 17% versus 16%, primary lung injury 12% versus 24%. Patients in group 1 were supported using several ventilatory and other modes (volume preset, non-inverse ratio ventilation, n = 15; pressure controlled inverse ratio ventilation (PC-IRV), n = 11; ultra high frequency jet ventilation (UHFJV), n = 13; an intravascular oxygenation device (IVOX) and extracorporeal gas exchange (ECGE), n = 2). Within group 1 no significant difference in mortality was observed between the patients on volume controlled ventilation and the remainder. In group 2 all patients received PC-IRV (n = 78) but, in addition, some received other support techniques (UHFJV n = 4, ECGE n = 2). In group 1 only sepsis on admission (21% (survivors) versus 56% (non-survivors)) predicted death. In group 2 age of survivors and non-survivors (41.2 (2.6) versus 52.6 (3.5)), APACHE score (12.2 (0.6) versus 15.8 (0.9)), and PaO2/FIO2 (12.8 (0.86) versus 10.5 (0.72)) predicted survival, but not the incidence of sepsis or multi-organ failure. CONCLUSIONS: In recent years a highly significant reduction in mortality associated with ARDS has been observed between two groups of patients well matched for disease severity and case mix. Changes in ICU organisation rather than specific interventions may account for this reduction, although different ventilatory and other management strategies used in the two groups may also be relevant.