webAIRS is a web-based de-identified anaesthesia incident reporting system, which was introduced in Australia and New Zealand in September 2009. By July 2016, 4,000 incident reports had been received. The incidents covered a wide range of patient age (<28 days to >90 years), American Society of Anesthesiologists physical status, and body mass index (<18.5 to >50 kg/m2). They occurred across a wide range of anaesthesia techniques and grade of anaesthesia provider, and over a wide range of anaesthetising locations and times of day. In a high proportion the outcome was not benign; about 26% of incidents were associated with patient harm and a further 4% with death. Incidents appeared to be an ever-present risk in anaesthetic practice, with extrapolated estimates exceeding 200 per week across Australia and New Zealand. Independent of outcomes, many anaesthesia incidents were associated with increased use of health resources. The four most common main categories of incident were Respiratory/Airway, Medication, Cardiovascular, and Medical Device/Equipment. Over 50% of incidents were considered preventable. The narratives accompanying each incident provide a rich source of information, which will be analysed in subsequent reports on particular incident types. The summary data in this initial overview are a sober reminder of the prevalence and unpredictability of anaesthesia incidents, and their potential morbidity and mortality. The data justify current efforts to better prevent and manage anaesthesia incidents in Australia and New Zealand, and identify areas in which increased resources or additional initiatives may be required.

Bow-tie analysis is a risk analysis and management tool that has been readily adopted into routine practice in many high reliability industries such as engineering, aviation and emergency services. However, it has received little exposure so far in healthcare. Nevertheless, its simplicity, versatility, and pictorial display may have benefits for the analysis of a range of healthcare risks, including complex and multiple risks and their interactions. Bow-tie diagrams are a combination of a fault tree and an event tree, which when combined take the shape of a bow tie. Central to bow-tie methodology is the concept of an undesired or 'Top Event', which occurs if a hazard progresses past all prevention controls. Top Events may also occasionally occur idiosyncratically. Irrespective of the cause of a Top Event, mitigation and recovery controls may influence the outcome. Hence the relationship of hazard to outcome can be viewed in one diagram along with possible causal sequences or accident trajectories. Potential uses for bow-tie diagrams in anaesthesia risk management include improved understanding of anaesthesia hazards and risks, pre-emptive identification of absent or inadequate hazard controls, investigation of clinical incidents, teaching anaesthesia risk management, and demonstrating risk management strategies to third parties when required.

The first 4000 reports to the webAIRS anaesthesia incident reporting database were used to evaluate pulmonary aspiration in patients undergoing procedures under general anaesthesia or sedation. Demographic data, predisposing factors, outcome and potential preventative measures were evaluated. In these reports, 121 cases of aspiration were identified. Aspirated substances included gastric contents, bile type fluids, blood and solids; 60 (49.6%) patients were admitted to the intensive care unit/high dependency unit, and 43 (35.5%) required mechanical ventilation. Aspiration was associated with significant harm in >50% of reports, and eight (6.6%) patients died. Factors associated with a risk ratio of aspiration >1.5 and outside the 95% confidence interval for no event included: age >80 years, emergency procedure, procedure undertaken in freestanding day unit or gastroenterology department, procedure undertaken between 1800 and 2200 hours and endoscopy procedures. Only 11 (9%) cases appeared to be inadequately fasted, and 77 (64%) were definitely fasted. In the remaining 33 (27%), fasting was not mentioned. In 18 (14.9%) cases, aspiration occurred in the presence of cricoid pressure. Potential measures to prevent aspiration included using a cuffed endotracheal tube rather than a laryngeal mask airway in cases at high risk of aspiration and being made more aware of potential risk factors by improvements in team communication. Aspiration continues to be an important complication of anaesthesia, and one that can be difficult to predict and to prevent.

This report describes an analysis of patient and procedural factors associated with a higher proportion of harm or death versus no harm in the first 4,000 incidents reported to webAIRS. The report is supplementary to a previous cross-sectional report on the first 4,000 incidents reported to webAIRS. The aim of this analysis was to identify potential patient or procedural factors that are more common in incidents resulting in harm or death than in incidents with more benign outcomes. There was a >50% higher proportion of harm (versus no harm) for incidents in which the patient's body mass index (BMI) was <18.5 kg/m 2 , for incidents in post-anaesthesia care units and non-theatre procedural areas, and for incidents under the main category of cardiovascular or neurological. The proportion of incidents associated with death was also higher (risk ratio >1.5) for BMI <18.5 kg/m 2 , incidents in non-theatre procedural areas, and incidents under the main category of cardiovascular or neurological. In addition, the proportion of incidents associated with death was higher for incidents in which the patient's age was >80 years, the American Society of Anesthesiologists physical status was 4 or 5, incidents involving non-elective procedures, and incidents occurring afterhours (1800 to 0800 hours). When faced with incidents with these potential risk factors, anaesthetists should consider earlier interventions and request assistance at an earlier stage. Educational strategies on incident prevention and management should place even further emphasis on scenarios involving these factors.

A review of the first 4000 reports to the webAIRS anaesthesia incident reporting database was performed to analyse cases reported as difficult or failed intubation. Patient, task, caregiver and system factors were evaluated. Among the 4000 reports, there were 170 incidents of difficult or failed intubation. Difficult or failed intubation incidents were most common in the 40–59 years age group. More than half of cases were not predicted. A total of 40% involved patients with a body mass index >30 kg/m2 and 41% involved emergency cases. A third of the reports described multiple intubation attempts. Of the reports, 18% mentioned equipment problems including endotracheal tube cuff rupture, laryngoscope light failure, dysfunctional capnography and delays with availability of additional equipment to assist with intubation. Immediate outcomes included 40 cases of oxygen desaturation below 85%; of these cases, four required cardiopulmonary resuscitation. The majority of the incidents resulted in no harm or minor harm (45%). However, 12% suffered moderate harm, 3.5% severe harm and there were three deaths (although only one related to the airway incident). Despite advances and significant developments in airway management strategies, difficult and failed intubation still occurs. Although not all incidents are predictable, nor are all preventable, the information provided by this analysis might assist with future planning, preparation and management of difficult intubation.

This audit of airway incidents was conducted over six months in 12 tertiary level hospitals across Australia and New Zealand. During that time, 131,233 patients had airway management and 111 reports were submitted (incidence 0.08%). The airway incidents included a combination of difficult airway management (83), oxygen desaturation (58), aspiration (19), regurgitation (14), laryngospasm (16), airway bleeding (10), bronchospasm (5) and dental injury (4), which gave a total of 209 events in 111 reports. Most incidents occurred during general anaesthesia (GA; 83.8%) and normal working hours (81.1%). Forty-three percent were associated with head and neck surgery and 12.6% with upper abdominal procedures. Of these patients, 52% required further medical treatment or additional procedures and 16.2% required unplanned admission to an intensive care unit or a high dependency unit. A total of 31.5% of patients suffered from temporary harm and 1.8% from permanent harm. There was one death. The factors associated with a high relative risk (RR) of an airway incident included American Society of Anesthesiologists Physical Status (ASA PS) (ASA PS 2 versus 1, RR 1.75; ASA PS 3 versus 1, RR 3.56; ASA PS 4 versus 1, RR 6.1), and emergency surgery (RR 2.16 compared with elective). Sedation and monitored anaesthesia care were associated with lower RRs (RR 0.49 and RR 0.73 versus GA, respectively). Inadequate airway assessment, poor judgement and poor planning appeared to be contributors to these events. Future teaching and research should focus on these areas to further improve airway management and patient safety.

The role of preoperative fasting is well established in current anaesthetic practice with different guidelines for clear fluids and food. However, chewing gum may not be categorised as either food or drink by some patients, and may not always be specified in instructions given to patients about preoperative fasting. The aim of this paper was to review anaesthesia incidents involving gum chewing reported to webAIRS to obtain information on the risks, if any, of gum chewing during the preoperative fasting period. There were nine incidents involving chewing gum reported between late 2009 and early 2015. There were no adverse outcomes from the nine incidents other than postponement of surgery in three cases and cancellation in one. In particular, there were no reports of aspiration or airway obstruction. Nevertheless, there were five cases in which the gum was not detected preoperatively and was found in the patient's mouth either intraoperatively or postoperatively. These cases of undetected gum occurred despite patient and staff compliance with their current preoperative checklists. While the risk of increased gastric secretions related to chewing gum preoperatively are not known, the potential for airway obstruction if the gum is not detected and removed preoperatively is very real. We recommend that patients should be specifically advised to avoid gum chewing once fasting from clear fluids is commenced, and that a specific question regarding the presence of chewing gum should be added to all preoperative checklists.

The aim of this study was to analyse the incidents related to awareness during general anaesthesia in the first 4,000 cases reported to webAIRS-an anaesthetic incident reporting system established in Australia and New Zealand in 2009. Included incidents were those in which the reporter selected "neurological" as the main category and "awareness/dreaming/ nightmares" as a subcategory, those where the narrative report included the word "awareness" and those identified by the authors as possibly relevant to awareness. Sixty-one awareness-related incidents were analysed: 16 were classified as "awareness", 31 were classified as "no awareness but increased risk of awareness" and 14 were classified as "no awareness and no increased risk of awareness". Among 47 incidents in the former two categories, 42 (89%) were associated with low anaesthetic delivery and 24 (51%) were associated with signs of intraoperative wakefulness. Memory of intraoperative events caused significant ongoing distress for five of the 16 awareness patients. Patients continue to be put at risk of awareness by a range of well-described errors (such as syringe swaps) but also by some new errors related to recently introduced anaesthetic equipment, such as electronic anaesthesia workstations.