A rude awakening after our fourth ‘NAP’: lessons for airway management

Endotracheal Intubation Performance in Novices: Comparing the Training Effect Resulting From Two Airway Management Training Simulators

INTRODUCTION

Between 2011 and 2014, the Combat Casualty Training Consortium research study sought to evaluate all aspects of combat casualty care, including mortality, with a special focus on the incidence and causes of potentially preventable deaths among American combat fatalities. This study identified a major training gap in critical airway management. Because of the high rate of morbidity and mortality associated with poor or incorrect airway management, an effort to address this training gap was necessary.

MATERIALS AND METHODS

This experiment compared the training using the Advanced Joint Airway Management System, a novel high-fidelity airway simulator, relative to one of the most utilized simulators for endotracheal intubation (ETI) via a parallel group randomized control trial design. Before training, participants (n = 19) attempted an ETI on a cadaver using direct laryngoscopy. Performance during the attempt was recorded and scored by trained blinded raters. Participants were then randomly allocated to either novel or conventional training. Post-training, participants completed a second ETI under the same parameters. Analysis was completed via 2 × 2 mixed analysis of variance for (1) ETI Score, (2) Errors, (3) Critical Failures, and (4) Duration, across both the pre- and post-training tests and between the two groups.

RESULTS

A priori power analysis required a total sample size of 84 participants in this experimental design. Consequently, this study is under-powered to reach statistical significance. Scores for all trainees did improve with training, yet analyses did not reveal a difference in overall ETI score between the novel and conventional training group, at baseline or at the post-training test (P = .249).

CONCLUSION

The Advanced Joint Airway Management System simulator presents a training effect that is comparable to the conventional training model. However, given this study's small sample size, these results must be considered preliminary and further research is merited to draw firm conclusions about its impact on trainee performance. Future studies engaging larger cohorts of trainees and exploring the other capabilities of the Advanced Joint Airway Management System (cricothyroidotomy, needle chess decompression) are needed to further examine the educational potential of this novel airway management training system.

Major complications of airway management: a prospective multicentre observational study

We conducted an observational study of serious airway complications, using similar methods to the fourth UK National Audit Project (NAP4) over a period of 1 year across four hospitals in one region in the UK. We also conducted an activity survey over a week, using NAP4 methods to yield an estimate for relevant denominators to help interpret the primary data. There were 17 serious airway complications, defined as: failed airway management leading to cancellation of surgery (eight); airway management in recovery (five); unplanned intensive care admission (three); and unplanned emergency front of neck access (one). There were no reports of death or brain damage. This was an estimate of 0.028% (1 in 3600) complications using the denominator of 61,000 general anaesthetics per year in the region. Complications in patients with 'predicted easy' airways were rare (approximately 1 in 14,200), but 45 times more common in those with 'predicted difficult' airways (approximately 1 in 315). Airway management in both groups was similar (induction of anaesthesia followed by supraglottic airway or tracheal tube). Use of awake/sedation intubation, videolaryngoscopy and high-flow nasal oxygenation were uncommon even in the predicted difficult airway patients (in 2.7%, 32.4% and 9.5% of patients, respectively). We conclude that the incidence of serious airway complications is at least as high as it was during NAP4. Despite airway prediction being used, this is not informing subsequent management.

A prospective six-month audit of airway incidents during anaesthesia in twelve tertiary level hospitals across Australia and New Zealand

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.

An Anesthesiologist's Perspective on the History of Basic Airway Management: The "Modern" Era, 1960 to Present

This fourth and last installment of my history of basic airway management discusses the current (i.e., "modern") era of anesthesia and resuscitation, from 1960 to the present. These years were notable for the implementation of intermittent positive pressure ventilation inside and outside the operating room. Basic airway management in cardiopulmonary resuscitation (i.e., expired air ventilation) was de-emphasized, as the "A-B-C" (airway-breathing-circulation) protocol was replaced with the "C-A-B" (circulation-airway-breathing) intervention sequence. Basic airway management in the operating room (i.e., face-mask ventilation) lost its predominant position to advanced airway management, as balanced anesthesia replaced inhalation anesthesia. The one-hand, generic face-mask ventilation technique was inherited from the progressive era. In the new context of providing intermittent positive pressure ventilation, the generic technique generated an underpowered grip with a less effective seal and an unspecified airway maneuver. The significant advancement that had been made in understanding the pathophysiology of upper airway obstruction was thus poorly translated into practice. In contrast to consistent progress in advanced airway management, progress in basic airway techniques and devices stagnated.

Review article: Critical Care Airway Management eLearning modules

The Australasian College for Emergency Medicine (ACEM) has recently launched the Critical Care Airway Management eLearning modules to support emergency medicine trainees in developing their airway management skills in the ED. A team of emergency physicians and trainees worked collaboratively to develop the eLearning resources ensuring extensive stakeholder consultation. A comprehensive resource manual was written to provide learners with knowledge that underpins the modules. ACEM provided project coordination as well as administrative and technical team support to the production. Although specifically developed with early ACEM trainees in mind, it is envisaged the resources will be useful for all emergency clinicians. The project was funded by the Australian Commonwealth Department of Health.

Determination of gas flow through airway exchange catheters: measured and calculated values and dependence on pressure and entrainment

Serious complications have been described during oxygenation of patients with airway exchange catheters, due to catheter malpositioning, accidentally applied high airway pressures or high delivered volumes. In this in-vitro study, we analysed gas flow through various airway exchange catheters and described its dependence on driving pressure and entrainment. We applied driving pressures between 0.5 and 2.5 bar and observed maximal flow rates of 3.6 l.s(-1) . Measured gas flow values differed significantly from values calculated according to the Hagen-Poiseuille equation. Although flow restriction in ventilators and small-bore connectors will limit gas flow, large gas volumes may be unintentionally applied via the airway exchange catheters, leading to serious complications.

The 5th National Audit Project (NAP5) on accidental awareness during general anaesthesia: summary of main findings and risk factors

We present the main findings of the 5th National Audit Project on accidental awareness during general anaesthesia. Incidences were estimated using reports of accidental awareness as the numerator, and a parallel national anaesthetic activity survey to provide denominator data. The incidence of certain/probable and possible accidental awareness cases was ~1:19 600 anaesthetics (95% CI 1:16 700-23 450). However, there was considerable variation across subtypes of techniques or subspecialties. The incidence with neuromuscular blockade was ~1:8200 (1:7030-9700), and without it was ~1:135 900 (1:78 600-299 000). The cases of accidental awareness during general anaesthesia reported to 5th National Audit Project were overwhelmingly cases of unintended awareness during neuromuscular blockade. The incidence of accidental awareness during caesarean section was ~1:670 (1:380-1300). Two thirds (82, 66%) of cases of accidental awareness experiences arose in the dynamic phases of anaesthesia, namely induction of and emergence from anaesthesia. During induction of anaesthesia, contributory factors included: use of thiopental; rapid sequence induction; obesity; difficult airway management; neuromuscular blockade; and interruptions of anaesthetic delivery during movement from anaesthetic room to theatre. During emergence from anaesthesia, residual paralysis was perceived by patients as accidental awareness, and commonly related to a failure to ensure full return of motor capacity. One third (43, 33%) of accidental awareness events arose during the maintenance phase of anaesthesia, most due to problems at induction or towards the end of anaesthesia. Factors increasing the risk of accidental awareness included: female sex; age (younger adults, but not children); obesity; anaesthetist seniority (junior trainees); previous awareness; out-of-hours operating; emergencies; type of surgery (obstetric, cardiac, thoracic); and use of neuromuscular blockade. The following factors were not risk factors for accidental awareness: ASA physical status; race; and use or omission of nitrous oxide. We recommend that an anaesthetic checklist, to be an integral part of the World Health Organization Safer Surgery checklist, is introduced as an aid to preventing accidental awareness. This paper is a shortened version describing the main findings from 5th National Audit Project - the full report can be found at http://www.nationalauditprojects.org.uk/NAP5_home#pt.

5th National Audit Project (NAP5) on accidental awareness during general anaesthesia: summary of main findings and risk factors

We present the main findings of the 5th National Audit Project (NAP5) on accidental awareness during general anaesthesia (AAGA). Incidences were estimated using reports of accidental awareness as the numerator, and a parallel national anaesthetic activity survey to provide denominator data. The incidence of certain/probable and possible accidental awareness cases was ~1:19,600 anaesthetics (95% confidence interval 1:16,700-23,450). However, there was considerable variation across subtypes of techniques or subspecialities. The incidence with neuromuscular block (NMB) was ~1:8200 (1:7030-9700), and without, it was ~1:135,900 (1:78,600-299,000). The cases of AAGA reported to NAP5 were overwhelmingly cases of unintended awareness during NMB. The incidence of accidental awareness during Caesarean section was ~1:670 (1:380-1300). Two-thirds (82, 66%) of cases of accidental awareness experiences arose in the dynamic phases of anaesthesia, namely induction of and emergence from anaesthesia. During induction of anaesthesia, contributory factors included: use of thiopental, rapid sequence induction, obesity, difficult airway management, NMB, and interruptions of anaesthetic delivery during movement from anaesthetic room to theatre. During emergence from anaesthesia, residual paralysis was perceived by patients as accidental awareness, and commonly related to a failure to ensure full return of motor capacity. One-third (43, 33%) of accidental awareness events arose during the maintenance phase of anaesthesia, mostly due to problems at induction or towards the end of anaesthesia. Factors increasing the risk of accidental awareness included: female sex, age (younger adults, but not children), obesity, anaesthetist seniority (junior trainees), previous awareness, out-of-hours operating, emergencies, type of surgery (obstetric, cardiac, thoracic), and use of NMB. The following factors were not risk factors for accidental awareness: ASA physical status, race, and use or omission of nitrous oxide. We recommend that an anaesthetic checklist, to be an integral part of the World Health Organization Safer Surgery checklist, is introduced as an aid to preventing accidental awareness. This paper is a shortened version describing the main findings from NAP5--the full report can be found at http://www.nationalauditprojects.org.uk/NAP5_home.

A survey of anaesthetic practice in predicting difficult intubation in UK and Europe

CONTEXT

Unexpected difficulty in tracheal intubation is an intermittent and often terrifying problem for all practising anaesthetists. There are many preoperative assessment tests to predict a difficult laryngeal view or a difficult intubation, but we found no published evidence of how frequently these predictive tests are used or how useful they are perceived to be by anaesthetists.

OBJECTIVE

We decided to ask UK and non-UK anaesthetists attending the Annual Scientific Meeting of the European Society of Anaesthesiology about their practice in predicting difficult intubation.

DESIGN

The study was conceived as a survey.

SETTING

The airway tests were compiled into a questionnaire, hand distributed among anaesthetists at Euroanaesthesia - the European group (after excluding UK attendees) - and posted to randomly selected anaesthetists in the UK - the UK group.

PARTICIPANTS

Overall, 888 of 1230 (72%) questionnaires were completed. The response rate from the UK group of anaesthetists was 69% (481 of 700) and from the European group was 77% (407 of 530).

RESULTS

On a scale 1 (never) to 5 (always), the mean score for frequency of use was similar for both groups of anaesthetists and ranged from about 4 for mouth opening to about 1 for Nodding Donkey. The mean score for usefulness (1 = useless, 5 = extremely useful) ranged from about 3.7 to 2 for the same two tests. The UK group found most tests slightly less useful than did the European group. With regard to the frequency of assessing the airway, 9% of the European group, but 16% of the UK group, failed always (score 5) or regularly (score 4) to assess the airway before general anaesthesia. Furthermore, 21 and 36% of the UK and European groups, respectively, failed to do so before regional anaesthesia.

CONCLUSION

These results are a cause for concern with regard to both airway management training and patient safety.

Difficult Airway Society Guidelines for the management of tracheal extubation

Tracheal extubation is a high-risk phase of anaesthesia. The majority of problems that occur during extubation and emergence are of a minor nature, but a small and significant number may result in injury or death. The need for a strategy incorporating extubation is mentioned in several international airway management guidelines, but the subject is not discussed in detail, and the emphasis has been on extubation of the patient with a difficult airway. The Difficult Airway Society has developed guidelines for the safe management of tracheal extubation in adult peri-operative practice. The guidelines discuss the problems arising during extubation and recovery and promote a strategic, stepwise approach to extubation. They emphasise the importance of planning and preparation, and include practical techniques for use in clinical practice and recommendations for post-extubation care.

An evidence-based approach to airway management: is there a role for clinical practice guidelines?

Complications arising out of airway management represent an important cause of anaesthesia-associated morbidity and mortality. Anaesthetic practice itself can lead to preventable harm, a particular example being persistent attempts at direct laryngoscopy, that results in delay in employing alternative strategies (or devices) when intubation is difficult. When patients are injured, expert review is called upon and often concludes that airway management provided by the anaesthetists was substandard. Many training programmes do not offer their trainees structured or organised teaching in airway management and many trainees probably enter practice with limited skills to deal with difficult airways. The literature on the management of the difficult airway in anaesthesia practice (especially as it relates to new technology and salvage strategies) is expanding rapidly. New technologies and practised response algorithms may be helpful in the management of the difficult airway, reducing the potential for adverse patient outcomes. Specialist societies and national interest groups can play an important role by critically reviewing and then applying the evidence base to generate clinical practice guidelines. The recommendations contained in such guidelines should be based on the most current evidence and they should be reviewed regularly for their content and continued relevance.

Rapid sequence induction with rocuronium - a challenge to the gold standard

Succinylcholine has been indicted on account of the diverse risks associated with its administration, which include hyperkalemia, vagal arrest, and malignant hyperthermia. However, it provides excellent intubating conditions reliably and quickly, characteristics that sustain its appeal for use in the intensive care unit, where airway management is challenging. There is an increasing body of evidence, outlined here, that rocuronium is an acceptable alternative to succinylcholine.