Risk of Aspiration with Laryngeal Mask Airway: Precautions, Prevention, and General Concerns

2. What’s the risk of aspiration with the LMA? G Sidaras, JM Hunter. Is it safe to artificially ventilate a paralysed patient through the laryngeal mask? The jury is still out. BJA 2001; 86: 749-53 proven aspiration (experts) 1 in 11,000

3. Aspiration with the TT Aspiration 1 in 1100 • Cohen CJA 1986;30:84-92 Aspiration 1 in 900 to 1 in 4000 • Olsson Acta Scand 1986; 33:22-31 Aspiration 1 in 900 to 1 in 4000 • Warner MA Anesthesiology 1993; 78: 56-62

4. Face mask/ ETT Warner MA, Warner ME, Weber JG. Clinical significance of pulmonary aspiration during the peri-operative period. Anesthesiology1993; 78: 56-62 214,000 patients aspiration 1 in 4,000 elective 1 in 900 emergency 32.9% of aspirations occurred during laryngoscopy 35.9% during extubation

5. .Patient factors Full stomach (e.g. emergency surgery) Diseases and symptoms known to delay gastric emptying diabetes mellitus increased intracranial pressure hiatus hernia gastrointestinal obstruction recurrent regurgitation dyspeptic symptoms oesophageal disease (eg achalasis, pouches etc) History of upper gastrointestinal surgery Injured or receiving opioids or other drugs delaying gastric emptying Women in labour Morbid obesity Operation factors Upper abdominal surgery Lithotomy or the head-down position Laparoscopic cholecystectomy Anaesthesia factors Inadequate anaesthesia Intermittent positive pressure ventilation particularly with high airway pressures Prolonged anaesthesia (is there evidence for this?) Removal of the airway before spontaneous recovery from anaesthesia Device factors Presence of a supraglottic airway inserted into the hypopharynx Incorrectly inserted airway Absence of drain/vent low seal with oropharynx low internal volume of supraglottic device device tip that fails to obturate the oesophageal inlet Predisposing factors increasing risk of pulmonary aspiration (Who is at increased risk of pulmonary aspiration?Asai T. Br J Anaesth. 2004 ;93: 497-500.)

6. Headline Aspiration was the commonest cause of death in anaesthesia cases reported to NAP4 (>20% of reported cases) Aspiration of gastric contents accounted for 50% of anaesthesia-related deaths. Many who survived did so only after a prolonged time on ICU. Aspiration of blood clots led to two cardiac arrests including one death. There was incomplete assessment of aspiration risk and failure to alter anaesthetic technique when aspiration risk was present. An excess of the cases involved emergency surgery and trainee anaesthetists.

7. There were clear examples of aspiration occurring at induction when classical indications for RSI were present and it was not used. Many aspirations occurred during maintenance while a standard LM. There was failure to identify risk and a failure to use available precautions to reduce the risk of such events: e.g. RSI for higher risk cases and the use of 2nd generation SADs for patients at lower risk. Aspiration and its prevention should remain major concerns for all anaesthetists.

8. Assessment of risk • Aspiration before airway management • Aspiration when RSI indicated • Aspiration during laryngoscopy or RSI • Aspiration and the standard LM • Supervision, training • Aspiration of blood

9. .....assessment

10. .....assessment • 27 of 29 aspirations during anaesthesia had risk factors • The commonest intended airway was a standard LM...... it seems a risk of aspiration rarely led to a change of airway plan. • Poor communication contributed to several events

11. ......communication

12. ….before airway management

13. ….when RSI indicated

14. ….when RSI indicated

15. ….when RSI indicated In many of these cases no concession had been made to an increased risk of aspiration

16. …….during RSI

17. ….and the LM 13 cases of aspiration with 1st generation SADs 11 cases of aspiration after placement of an LM 1 secondary aspiration with i-gel 13/14 had identifiable risk factors In four, use of such a device ‘very ill-advised’ 2nd generation SADs 10% of SAD use in census

18. ....blood After dental surgery in a sick cardiac patient. Post-extubation hypoxia. Re-intubation. Cardiac arrest. CPR. Flat capnograph. Ten minutes later tracheal suction removed copious clots and ventilation was then possible. The patient was admitted to IC U and made a slow but full recovery.

19. ....blood Two cases led to cardiac arrest Both recovery After dental surgery in a sick cardiac patient. Post-extubation hypoxia. Reintubation. Cardiac arrest. CPR. Flat capnograph. Ten minutes later tracheal suction removed copious clots and ventilation was then possible. The patient was admitted to IC U and made a slow but full recovery.

20. Numbers 42 cases: 23% of all cases 34 anaesthesia: 26% of cases • 9 deaths (8 gastric contents, 1 blood) • 2 cases of brain damage • 50% of anaesthesia deaths • 53% of anaesthesia death and BD

22. Death • Hypoxia (mild early) • Often airway obstruction • RS and CVS deterioration, ARDS ICU admission • Dichotomy of outcomes

23. 2/3 aged >61 years 2/3 ASA 1-2 34% obese 72% emergency surgery (38% in non aspiration cases) 52% trainees (22% of non-aspiration cases) • 43% of reports to NAP4 by trainees were aspiration, 15% of those reported by consultants 2/3 ‘carry on with case’

24. Quality of care Reporter Root cause: 10/12 = poor judgement Review panel (23 primary anaesthetic aspirations) 4 good 7 mixed 8 poor 4 not assessable

25. conclusion NAP4 saw an unwelcome tide of aspiration cases. Aspiration was the leading cause of patient death and death/brain damage during anaesthesia. The majority of cases could have been managed better, with the possibility of preventing the event.

29. Aspiration, death http://www.thisislincolnshire.co.uk/news/boston/Inquest-hears-patient-s-nightmare-complications/article-3564757-detail/article.html

30. Aspiration, death http://www.thisislincolnshire.co.uk/news/boston/Inquest-hears-patient-s-nightmare-complications/article-3564757-detail/article.html