NAP4 is here! Is that good? Yes. Why? Because it’s the long awaited 4th National Audit Project of the Royal College of Anaesthetists and the Difficult Airway Society in the United Kingdom – a multi-phase national survey that was designed to answer the questions;
- What types of airway device are used during anaesthesia and how often?
- How often do major complications, leading to serious harm, occur in association with airway management in anaesthesia, in the intensive care units and in the emergency departments of the UK?
- What is the nature of these events and what can we learn from them, in order to reduce their frequency and consequences?
The Audit identified 33 deaths and 46 cases of death or brain damage as a result of airway complications during anaesthesia, in ICU and the emergency department over a one year period in the four countries of the United Kingdom.
Some major findings include:
- Poor planning contributed to poor airway outcomes – often a failure to plan for failure.
- The project identified numerous cases where awake fibreoptic intubation (afoi) was indicated but was not used. A lack of suitable equipment was prevalent on ICU.
- Problems arose when difficult intubation was managed by multiple repeat attempts at intubation.
- Events were reported where supraglottic airway devices (SAD) were used inappropriately. Patients who were markedly obese, often managed by junior trainees, were prominent in the group of patients who sustained non-aspiration events. Numerous cases of aspiration occurred during use of a first generation SAD in patients who had multiple risk factors for aspiration and in several in whom the aspiration risk was so high that rapid sequence induction, should have been used.
- The proportion of obese patients in case reports submitted to NAP4 was twice that in the general population
- When rescue techniques were necessary in obese patient they failed more often than in the non-obese.
Here’s my favourite bit so far – in keeping with what the literature has already told us about this technique:
There was a high failure rate of emergency cannula cricothyroidotomy, approximately 60%. There were numerous mechanisms of failure and the root cause was not determined; equipment, training, insertion technique and ventilation technique all led to failure. In contrast a surgical technique for emergency surgical airway was almost universally successful. The technique of cannula cricothyroidotomy needs to be taught and performed to the highest standards to maximise the chances of success, but the possibility that it is intrinsically inferior to a surgical technique should also be considered. Anaesthetists should be trained to perform a surgical airway.
- failure to correctly interpret a capnograph trace led to several oesophageal intubations going unrecognised in anaesthesia. A flat capnograph trace indicates lack of ventilation of the lungs: the tube is either not in the trachea or the airway is completely obstructed. Active efforts should be taken to positively exclude these diagnoses. This applies equally in cardiac arrest as CPR leads to an attenuated but visible expired carbon dioxide trace.
- at least one in four major airway events reported to NAP4 was from ICU or the emergency department. The outcome of these events was more likely to lead to permanent harm or death than events in anaesthesia. Analysis of the cases identified gaps in care that included: poor identification of at-risk patients, poor or incomplete planning, inadequate provision of skilled staff and equipment to manage these events successfully, delayed recognition of events and failed rescue due to lack of or failure of interpretation of capnography. The project findings suggest avoidable deaths due to airway complications occur in ICU and the emergency department.
- failure to use capnography in ventilated patients likely contributed to more than 70% of ICU related deaths. Increasing use of capnography on ICU is the single change with the greatest potential to prevent deaths such as those reported to NAP4.
- Displaced tracheostomy, and to a lesser extent displaced tracheal tubes, were the greatest cause of major morbidity and mortality in ICU. Obese patients were at particular risk of such events and adverse outcome from them. All patients on ICU should have an emergency re-intubation plan.
- Most events in the emergency department were complications of rapid sequence induction. This was also an area of concern in ICU. RSI outside the operating theatre requires the same level of equipment and support as is needed during anaesthesia. This includes capnography and access for equipment needed to manage routine and difficult airway problems.
These are just snippets – there is much more in the report, and I’m still going through it.
The Executive Summary and all other Sections of NAP4 can be downloaded here from the Royal College of Anaesthetists