NAP 4 project Obstructed Airway

1. NAP 4 projectObstructed Airway Dr Adrian Pearce Guy’s and St Thomas’ Hospital

2. A patient with an advanced transglottic tumour required tracheostomy prior to radiotherapy. Anaesthesia was induced with total intravenous anaesthesia in the anaesthetic room. Intubation was attempted unsuccessfully by rigid videolaryngoscopy. Rapid oxygen desaturation developed and both facemask ventilation and needle cricothyroidotomy failed. A late peri-arrest attempt at intubation was made by the surgeon. The patient died in the anaesthetic room.

3. NAP 4 data for Head and Neck disease 72 reports (55 anaesthesia, 10 ICU/HDU, 7 ED forms) More than one-third of all cases in the project 70% patients in this group had obstructed airway Qualifying events: Death or brain damage 13 Emergency surgical airway 50 Unexpected ICU admission 27 Outcome at time of form completion: Death 17 Partial recovery 2 Full recovery 51 Not recorded 2

4. Airway obstruction is the clinical situation in which a patient develops signs or symptoms due to narrowing or ? distortion of the airway Airway obstruction is a blockage of the airway, resulting in reduced or absent gas flow to and from the alveoli Flavell EM, Stacey MR, Hall JE Clinical management of airway obstruction. Current Anaesthesia and Critical Care 2009, 20: 102-112 Anaesthesia for diagnostic/resective surgery NAP 4 data ~ 50 patients with airway obstruction Airway intervention to maintain airway Patients admitted via ED Patients in ICU

5. An ASA 3 elderly patient was scheduled for panendoscopy and biopsy of a presumed airway tumour. Preoperatively, the patient appeared comfortable, with mild stridor and was able to lie flat without any distress. No airway investigations had been undertaken and general anaesthesia was induced. The tumour obscured the larynx, intubation and mask ventilation were impossible and the patient suffered a cardiac arrest from gross hypoxia. The ENT surgeon performed an urgent surgical tracheostomy and the patient was resuscitated. The patient died several months later from inoperable disease.

6. A middle aged, but not obese patient was scheduled for biopsy of a suspected tumour of the base of tongue. The patient had undergone radiotherapy to the head/neck following the discovery of a malignant neck node four years previously and had continued to smoke. The consultant anaesthetist did not expect any particular problems. However, after induction of general anaesthesia, on attempting laryngoscopy no recognisable laryngeal structures could be seen and mask ventilation was difficult. Fibreoptic endoscopy showed an ‘inflamed and swollen epiglottis’ and fibreoptic intubation was not successful. The patient had an emergency surgical tracheostomy in the anaesthetic room with satisfactory maintenance of oxygenation via facemask ventilation.

7. Learning points • Anaesthetists should be familiar with the tools of assessment of the airway • Stridor/respiratory distress at rest may not be present in chronic obstruction • Flexible nasendoscopy is very useful and was the commonest additional airway investigation • There is benefit in reviewing all scans/endoscopy with the surgeon prior to starting

8. Learning point • The anaesthetist should try to have a good idea of the - Degree of narrowing - Site of narrowing above the vocal cords involving vocal cords below vocal cords - Type of narrowing before starting

9. A middle aged ASA 3, slim patient presented for elective clearance of infected tissue following pharyngeal surgery and radiotherapy. Facemask ventilation, direct laryngoscopy, laryngeal mask placement and direct tracheal access were all predicted to be difficult. Facemask ventilation was optimal following induction of anaesthesia and muscle relaxation but deteriorated after four attempts at direct laryngoscopy with increasing bleeding, oedema and secretions. Ventilation became impossible and a surgical tracheostomy was performed.

10. An elderly, ASA 3 patient was known to have a grade 4 direct laryngoscopy view due to oral carcinoma and radiotherapy. Presented as an emergency with stridor. Inhalational induction with halothane failed, ventilation was impossible and the patient deteriorated to PEA cardiac arrest requiring CPR. Attempted fibreoptic intubation failed and the airway was successfully rescued with a surgical airway.

11. An elderly, ASA 4 patient presented with stridor, due to invasive thyroid carcinoma. Inhalational induction and maintenance of spontaneous ventilation with sevoflurane was planned. Following induction, airway obstruction and laryngospasm occurred. No muscle relaxant was administered. Direct laryngoscopy revealed a grade 2 laryngeal view, attempted intubation resulted in trauma and oedema with no ventilation. A surgical airway was required.

12. A young fit and slim adult presented with a dental abscess and facial swelling. Inhalational induction and maintenance of spontaneous ventilation with sevoflurane was planned. Following induction airway obstruction and laryngospasm occurred. No muscle relaxant was administered, airway obstruction persisted with desaturation. Direct laryngoscopy and laryngeal mask ventilation failed. Airway obstruction and inability to ventilate required a surgical airway.

13. Inhalational induction – what actually happened • A theme that emerged from the project data was the deterioration in the airway following inhalational induction and subsequent inability to maintain spontaneous ventilation. • Following induction of anaesthesia; • No compromise to spontaneous ventilation in 4 patients • Airway compromise with oxygen desaturation in 12 patients • Failure of ventilation, either because the airway deteriorated further or after direct laryngoscopy attempts were made in 11 patients

14. Direct laryngoscopy – what actually happened Another consistent theme to emerge from patients with head and neck pathology was the deterioration in the airway following single or repeated attempts at direct laryngoscopy. Following induction of anaesthesia and attempts at direct laryngoscopy the airway deteriorated with increasing difficulty in ventilation in 13 patients. With repeated attempts the airway became impossible to ventilate in 15 patients. All these 15 patients subsequently required a surgical airway.

15. Flexible fibreoptic techniques - what actually happened 23 attempts to use flexible fibreoptic techniques 14 failed 9 successful Of the 14 failures with this technique 4 awake and 10 asleep Awake failure was due to an inability to either identify the glottic inlet or an inability to pass either the fibreoptic scope or tracheal tube. Asleep fibreoptic failure in ten patients was as a result of repeated attempts, inability to identify the glottic inlet, inability to pass the fibreoptic scope or the tracheal tube, bleeding and airway obstruction. In those patients where fibreoptic techniques were unsuccessful a surgical airway was usually required.

16. Needle cricothyrotomy often fails Of 27 uses of cannula cricothyroidotomy in head and neck patients 12 were successful (by both large and small bore devices) and 15 failed. Failure of cannula cricothyroidotomy was due to misplacement, inability to place, fracture, kinking, blockage, dislodgement and barotrauma. It is important to recognise that cannula cricothyroidotomy has a significant failure rate in CICV, and for head and neck patients a surgical tracheostomy is often required.

17. We may love our anaesthetic rooms but …. • A patient bleeding after radical neck dissection returned to theatre in the early hours of the morning. The patient was asymptomatic apart from a dull ache and previous laryngoscopy was grade 2. • The anaesthetist undertook a RSI in the anaesthetic room. • At laryngoscopy the tissues were completely oedematous • Larynx was not visible. • A blind attempt in placing a bougie failed. • A prepared fibrescope was inserted but again no landmarks • Ventilation via a SAD failed • Large-cannula cricothyroidotomy was performed but unsuccessful • The patient was rushed into theatre for a surgical tracheostomy with an intubating LMA in place but before intubation through this was started the thiopentone and suxamethonium used at induction wore off enabling the patient to awaken. A difficult awake tracheostomy was undertaken and the patient made a full recovery.

18. What can NAP4 tell us about the best approach to managing the obstructed airway? We must move away from talking about primary plans (I am going to do an inhalational/IV/fibreoptic) to formulating logical, coherent strategies There must be a strategy of primary and back-up plans with all the equipment and personnel ready before starting The outcome depends on the strategy adopted and not the initial or primary approach to securing the airway There is no obvious benefit in starting difficult cases in the anaesthetic room when the back-up/rescue plan involves other members of the theatre/surgical team Needle cricothyrotomy has a high failure rate in practice – urgent surgical tracheostomy appears to be a more successful back-up

19. Limitations on NAP4 and the obstructed airway • Successful primary tracheostomy under LA or GA was not reported to the project • A rescue surgical airway may well be part of an excellently planned and managed obstructed airway • ‘Successful’ airway management which did not lead to a qualifying event was not reported

20. Recommendations for management of the obstructed airway 1 • Senior anaesthetic and surgical staff should be involved • Anaesthetists should gain useful information from CT, MR imaging and nasendoscopy whenever possible • Airway investigations should be reviewed jointly by the surgeon and anaesthetist • The level of obstruction in the airway should be determined whenever possible

21. Recommendations for management of the obstructed airway 2 • If no additional investigations are available consideration should be given to awake nasendoscopy in theatre to reassess the situation prior to starting • An agreed airway management strategy should be formulated by the anaesthetist, surgeon and theatre team prior to starting • The anaesthetic management of any case in which surgical tracheostomy is a rescue option should start in the operating theatre with everyone assembled and ready

22. Recommendations for management of the obstructed airway 3 • Multiple attempts at direct laryngoscopy should be avoided • If FOI is the primary plan, there are good reasons for undertaking this in the awake patient and this should be considered • Inhalational induction may fail with loss of airway and failure to wake and a clear rescue plan should be ready • Emergency needle or large-bore cricothyrotomy cannot be assumed to be possible or successful

23. Recommendations for management of the obstructed airway 4 • The team managing the patient should not disperse after extubation until the airway is safe • Patients in ICU (intubated or with tracheostomy) require a continuously-ready strategy for reintubation if the tube dislodges or blocks

24. A patient with an advanced transglottic tumour required tracheostomy prior to radiotherapy. Anaesthesia was induced with total intravenous anaesthesia in the anaesthetic room. Intubation was attempted unsuccessfully by rigid videolaryngoscopy. Rapid oxygen desaturation developed and both facemask ventilation and needle cricothyroidotomy failed. A late peri-arrest attempt at intubation was made by the surgeon. The patient died in the anaesthetic room. The report illustrating the largest number of learning points