NAP4 Project Assessment and planning

1. NAP4 ProjectAssessment and planning Dr Adrian Pearce Guy’s and St Thomas’ Hospital London

2. An elderly patient presented for an elective video-assisted thoracic procedure. No airway assessment was undertaken and (consequently) no airway management problem was anticipated preoperatively. After induction of anaesthesia, including muscle relaxation, direct laryngoscopy was very difficult with the report noting ‘limited neck extension and prominent teeth’. Multiple attempts at intubation failed, the procedure was abandoned and a SAD inserted. On return of spontaneous breathing and awakening the SAD was removed but the oxygen saturations remained low. After 10 minutes with oxygen saturations in the 80s, the cardiothoracic surgeon inserted a percutaneous tracheostomy.

3. ‘An anaesthetist must assess the patient before anaesthesia and devise an appropriate plan of anaesthetic management’ - The Good Anaesthetist, Royal College of Anaesthetists, 2010. ‘The preoperative assessment process should have identified and addressed problems with individual patients.’ – Pre-operative Assessment and Patient Preparation, Association of Anaesthetists of Great Britain and Ireland, 2010. NAP 4 Project 133 Anaesthesia forms 28 reports airway assessment ‘not recorded’ 9 reports field left blank ~ 25% reports had no written information on airway assessment ‘A minimum examination of dental health, inter-dental distance and mandibular protrusion should be routine. It would be unconscionable to find that a patient had an interdental distance of only 1 cm after induction’ Dr Ian Calder, 2011

4. 133 Anaesthesia reports Difficulty with airway management anticipated 66 not anticipated 67 Anticipated problems Difficult direct laryngoscopy/intubation 56 Difficult facemask 21 Difficult direct access 18 Difficult SAD 10 Difficult preoxygenation 8 Anticipated problems allow planning but The adopted strategy must be likely to deal with the anticipated problems in the safest/best way

5. A non-obese adult with trismus was scheduled for removal of infected mandibular plate during daylight hours. The anaesthetist assessed the airway and anticipated that problems would be present in this airway compromised by pharyngeal oedema, radiotherapy and infection. The specific problems identified were difficult facemask ventilation, difficult direct laryngoscopy/intubation, difficult SAD insertion and difficult direct tracheal access. Patient cooperation was not expected to be a problem. Anaesthesia was induced and rocuronium administered. After unsuccessful attempts at fibreoptic intubation and with difficult ventilation (oxygen saturations falling to 25%) the airway was eventually rescued by difficult surgical tracheostomy. Difficult direct laryngoscopy and difficult facemask ventilation = secure airway awake

6. An adult patient with ankylosing spondylitis required surgery during daylight hours for intestinal obstruction. Difficult direct laryngoscopy and risk of aspiration were predicted by the consultant anaesthetist. The patient was managed by a rapid sequence induction with propofol, suxamethonium and cricoid force. When intubation by direct laryngoscopy was not possible rocuronium was administered and attempts were made to intubate through a SAD with a flexible fibrescope. When this also failed further relaxant was administered and the laparotomy was carried out with a SAD. The induction process took 1 hr. Difficult direct laryngoscopy and risk of aspiration = secure airway awake

7. An adult patient with ankylosing spondylitis required surgery during daylight hours for intestinal obstruction. Difficult direct laryngoscopy and risk of aspiration were predicted by the consultant anaesthetist. The patient was managed by a rapid sequence induction with propofol, suxamethonium and cricoid force. When intubation by direct laryngoscopy was not possible rocuronium was administered and attempts were made to intubate through a SAD with a flexible fibrescope. When this also failed further relaxant was administered and the laparotomy was carried out with a SAD. The induction process took 1 hr. Failed intubation at RSI and non-emergency = wake-up patient

8. NAP4 identified these unanticipated clinical situations as the ones for which all anaesthetists should have a prepared strategy Failed direct laryngoscopy Failed ventilation Failed intubation at RSI Aspiration with SAD Loss of airway with SAD Extubation/recovery problems A strategy is a combination of plans constructed specifically to deal with a problem The more commonly the adopted strategy is a national or locally agreed one, the greater likelihood that it will be executed successfully by the team

9. Awake fibreoptic intubation was sometimes not selected as part of the strategy even when it would seem ideal…. A 115 kg patient with sleep apnoea, limited cervical spine mobility and tracheal deviation was scheduled for thyroidectomy. General anaesthesia was induced with remifentanil, propofol and sevoflurane. It was not possible to see the vocal cords at direct laryngoscopy and after repositioning it was not possible to ventilate the patient either. Cricothyroidotomy was not possible and the airway was secured by difficult tracheostomy. Saturations were < 60% for 20 minutes. If awake intubation would be ‘best’ but an individual anaesthetist cannot perform one, should the anaesthetic department have collective responsibility to provide someone who can?

10. What is an inhalational induction…? Does a combination of remifentanil infusion, propofol and a volatile agent qualify? What will happen when the airway fails – try a muscle relaxant, wake up, cricothyrotomy? In reports it was clear that some patients were neither awake nor sufficiently anaesthetised and the airway could not be maintained

11. Is the anaesthetic room always the correct place to start? The anaesthetic room; Is usually small or narrow Difficult to get assistance and surgical equipment in place Fairly soundproof Distant to other members of the team Poorly lit for surgery No diathermy Beds are awkward for surgeons If surgical help is part of the strategy – start in the operating theatre

12. Aspiration risk Not increased in 83 anaesthesia reports - but in 9 of these patients aspiration was the root cause of poor outcome Increased in 43 reports; Intestinal obstruction 8 Reflux 8 Recent ingestion 7 Delayed gastric emptying 7 Pregnancy 4 There was more problem with failing to protect the airway than in trying to protect it by tracheal intubation

13. NAP4 Assessment - Good News • Predicted causes of adverse events • No airway evaluation performed • Evaluation imperfect in prediction • No airway strategy formulated • Inappropriate strategy • Best practice strategy fails • Team unable to complete strategy • Resources cannot be assembled Current model (ASA inspired) Assessment of the airway Preparation for difficulty Strategy at intubation Strategy at extubation Follow-up All predicted causes of adverse events were seen in NAP4 – there were no new ones Therefore our current model of airway management is still valid

14. Recommendations All patients should have an airway assessment performed and recorded The risk of aspiration should be assessed and the adopted strategy adjusted appropriately Awake intubation should be used when indicated. Both individuals and anaesthetic departments should ensure such a service is readily available All anaesthetic departments should have an explicit policy for management of failed or difficult intubation Individuals should use these strategies in their daily practice