The Royal College of Anaesthetists National Audit Projects (NAPs) study major complications of anaesthesia, and concurrently review current practice and use the findings to improve patient care. The 6th National Audit Project of the Royal College of Anaesthetists (NAP6), is a large-scale prospective service evaluation of perioperative anaphylaxis across the hospitals of the United Kingdom. It has gathered comprehensive quantitative and qualitative information on these clinical events, enabling the anaesthetic and allergy/immunology communities to collaborate in order to make recommendations for the improvement of the quality of patient care (Chapter 5, Methods; Chapter 6 Main findings; Chapter 14, Investigation).

The majority of previous reports have included all grades of perioperative hypersensitivity and all report similar patterns of clinical features (Table 1). In a small number of cases, there may be single organ-system involvement, and cutaneous features predominate in mild, non-IgE-mediated perioperative hypersensitivity (Mertes 2011a, Low 2016). Most studies agree that the clinical features of severe anaphylaxis are very similar regardless of whether allergic or non-allergic in nature.

BACKGROUND:The incidence of anaphylaxis might be increasing. Data for fatal anaphylaxis are limited because of the rarity of this outcome.OBJECTIVE:We sought to document trends in anaphylaxis admissions and fatalities by age, sex, and cause in England and Wales over a 20-year period.METHODS:We extracted data from national databases that record hospital admissions and fatalities caused by anaphylaxis in England and Wales (1992-2012) and crosschecked fatalities against a prospective fatal anaphylaxis registry. We examined time trends and age distribution for fatal anaphylaxis caused by food, drugs, and insect stings.RESULTS:Hospital admissions from all-cause anaphylaxis increased by 615% over the time period studied, but annual fatality rates remained stable at 0.047 cases (95% CI, 0.042-0.052 cases) per 100,000 population. Admission and fatality rates for drug- and insect sting-induced anaphylaxis were highest in the group aged 60 years and older. In contrast, admissions because of food-triggered anaphylaxis were most common in young people, with a marked peak in the incidence of fatal food reactions during the second and third decades of life. These findings are not explained by age-related differences in rates of hospitalization.CONCLUSIONS:Hospitalizations for anaphylaxis increased between 1992 and 2012, but the incidence of fatal anaphylaxis did not. This might be due to increasing awareness of the diagnosis, shifting patterns of behavior in patients and health care providers, or both. The age distribution of fatal anaphylaxis varies significantly according to the nature of the eliciting agent, which suggests a specific vulnerability to severe outcomes from food-induced allergic reactions in the second and third decades.

Small case series suggest that teenagers and young adults may be at higher risk of fatal food-induced anaphylaxis than other age groups, but this has not been confirmed in large population-based datasets. We extracted data from national databases for hospital admissions and fatalities due to anaphylaxis in England and Wales for the period 1992-2011, and cross-checked fatalities against a prospective fatal anaphylaxis registry. We examined time trends and age distribution for fatal reactions caused by food, drugs and insect stings, and compared these to equivalent data previously published from Australia. Hospital admissions due to anaphylaxis admissions increased steadily over the time periods studied in both the UK and Australia, but fatality rates have remained stable at around 0.04 (UK) and 0.05 (Aus) cases per 100,000 population per annum. Fatalities and admissions were most common in older people for drug- and insect sting-induced anaphylaxis. For food-triggered reactions, fatalities were most common in teenagers and young adults, in both countries. These findings are not explained by age-related differences in the prevalence of food anaphylaxis requiring hospitalisation. In the UK and Australia, hospitalisations for anaphylaxis have increased, but fatal anaphylaxis has not. Possible explanations include increasing recognition of anaphylaxis, improved management and a real increase in the prevalence of food allergy. Of note, the age-distribution of fatal cases varies significantly according to the nature of the eliciting agent, and raises important questions about the differences in the pathogenesis of anaphylaxis between different triggers.

*The UK incidence of anaphylactic reactions is increasing. *Patients who have an anaphylactic reaction have life-threatening airway and, or breathing and, or circulation problems usually associated with skin or mucosal changes. *Patients having an anaphylactic reaction should be treated using the Airway, Breathing, Circulation, Disability, Exposure (ABCDE) approach. *Anaphylactic reactions are not easy to study with randomised controlled trials. There are, however, systematic reviews of the available evidence and a wealth of clinical experience to help formulate guidelines. *The exact treatment will depend on the patient's location, the equipment and drugs available, and the skills of those treating the anaphylactic reaction. *Early treatment with intramuscular adrenaline is the treatment of choice for patients having an anaphylactic reaction. *Despite previous guidelines, there is still confusion about the indications, dose and route of adrenaline. *Intravenous adrenaline must only be used in certain specialist settings and only by those skilled and experienced in its use. *All those who are suspected of having had an anaphylactic reaction should be referred to a specialist in allergy. *Individuals who are at high risk of an anaphylactic reaction should carry an adrenaline auto-injector and receive training and support in its use. *There is a need for further research about the diagnosis, treatment and prevention of anaphylactic reactions.

In a comparative multicentre study in the United States, the neuromuscular-blocking and safety profile of cisatracurium and vecuronium has been evaluated in critically ill, intensive care unit (ICU) patients requiring long-term neuromuscular block (up to 6 days) to facilitate mechanical ventilation. The mean infusion rate of cisatracurium needed to produce sufficient neuromuscular block to facilitate mechanical ventilation was approximately one-third of the mean infusion rate needed for atracurium. The mean time for recovery to a T4: T1 ratio of ≥0.7 was 60 min (median 50 min) for cisatracurium (as assessed by the twitch response of the adductor pollicis muscle to trains of four numbered stimulations). This value for cisatracurium was similar to that previously reported for atracurium. In contrast, the mean recovery time for vecuronium was over 380 min (median 178 min). Cisatracurium was well tolerated when given as a long-term infusion to critically ill patients; no episodes of seizure or myopathy were observed. One patient given vecuronium experienced prolonged weakness, with myopathy and neuropathy. There was a much lower incidence of prolonged drug effect in patients given cisatracurium than in patients given vecuronium. The neuromuscular-blocking and safety profile of cisatracurium make it a suitable neuromuscular-blocking drug for use in critically ill patients in the ICU.