Duties and responsibilities
Anesthesia airway management
An article for physicians by physicians
Originally published September 2005 / Revised May 2008
A study examining the
Of interest to physicians managing airways
An analysis of the CMPA's closed legal actions 1993-2003
A search of legal actions closed between 1993 and 2003 identified 33 cases naming an anesthesiologist and involving the issue of airway management. A review of the synopses found 16 cases where the airway issue was central to the legal action. In the remainder of the files the clinical occurrence was either an aspiration outside of the setting of a difficult airway or the airway issue was not central to the case.
Summary of cases
The 16 cases were reviewed in detail and some of the general characteristics are presented below:
Duration (the average time from when the file was opened until it was concluded)
- 52 months (range 12 to 181 months).
- 13 females, three males.
- Average age 41.5 years (range 27 to 62), 11 were under 50 years of age.
- 13 were elective; two were non-elective, but non-emergent; and one was an emergency.
- In 12 cases the anesthesiologist alone was responsible for the care.
- Students were involved in four cases, all under the direct supervision of an anesthesiologist.
History and examination
- Four cases had a documented airway history and examination.
- 11 patients did not have a documented airway history or examination.
- In one case there was no attempt to take a history or perform an airway examination. This patient had a history of a difficult airway with a previous surgery being cancelled because her trachea could not be intubated.
Severity of injury sustained
- 13 of the 16 patients suffered moderate to severe brain damage or death.
Eight of the 16 cases were difficult intubations. Following preoperative evaluation, a difficult airway was anticipated in four patients, three patients were identified as being possibly difficult to intubate, and one was identified as possibly having a difficult airway without further specification.
For the four anticipated difficult airways, general anesthesia was induced and muscle relaxants employed in three cases, and in one case the anesthesiologist planned to do an awake intubation with a fiberoptic bronchoscope before induction of anesthesia.
- One patient could not be intubated despite multiple attempts by two anesthesiologists; a cannot-intubate, cannot-ventilate situation developed and a rescue tracheotomy was attempted; severe anoxic brain injury resulted.
- A second patient was successfully intubated by direct laryngoscopy; at the end of the surgery the tube was removed from the trachea. This patient subsequently developed respiratory insufficiency and reintubation was not successful. The patient arrested, was initially resuscitated, but was left with a severe anoxic injury; and died shortly thereafter.
- After induction of general anesthesia, intubation failed in the third patient. The anesthetic was reversed and spontaneous ventilation returned. A blind nasal intubation was then attempted without success; bleeding resulted and the patient arrested. A rescue tracheotomy was performed, but the patient was left with a severe anoxic brain injury.
- The fourth patient was successfully intubated while still awake with a flexible fiberoptic scope. At the completion of surgery, the trachea was extubated, the patient was unable to maintain an airway, the trachea could not be re-intubated, and the patient arrested and died.
In the eight difficult intubation cases, adjuncts and alternatives to the direct laryngoscope were not commonly used when difficult intubation was encountered. In three cases a stylet was placed in the endotracheal tube, in one case a second blade was tried. A laryngeal mask airway was placed in two cases as a rescue airway, but apparently did not provide for adequate ventilation. In four cases, a rescue tracheotomy was attempted; two patients developed anoxic brain injuries, one died and one recovered. All tracheotomies were performed when arrest was either imminent or already evident.
Of the 16 patients, esophageal intubations occurred in nine. In a tenth case, esophageal intubation was probable; the initial endotracheal tube was removed when the patient's condition became compromised and then replaced without verification of the tube's original position.
Of the nine known esophageal intubations:
- Seven were considered not difficult intubations (students were involved in three cases).
- One was considered difficult.
- One was both difficult to intubate and difficult to ventilate.
The seven esophageal intubations with no recognized difficulties were all tube misplacements.
In one case, the tube misplacement was immediately recognized, removed and correctly
re-sitedwith no sequelae.
- In three instances a student intubated the esophagus and the misplacement was not recognized until the patient was in cardiac arrest.
- There were three instances where pulse oximeters provided non-reassuring readings. It was not clear from the anesthetic record if these readings were recognized or responded to in a timely fashion. Two patients died and the third suffered anoxic brain injury.
- In three cases end-tidal carbon dioxide monitors were available but not used. Two patients died and the third suffered anoxic brain injury.
- In one case both pulse oximeter and endtidal carbon dioxide monitors were in use and gave non-reassuring readings. The tube was repositioned after considerable delay without confirming the original tube position. The patient suffered a significant neurological injury.
Of the 16 cases, nine were settled; two went to trial, both resulting in judgments for the plaintiff; and five were discontinued by the plaintiffs prior to trial.
Expert opinion from the cases
Preoperative assessment helpful:
The experts identified a preoperative assessment of the airway, including both a history and a structured physical examination, as likely helpful in predicting airway difficulties and formulating strategies for dealing with the anticipated difficulties. A review of the anesthetic records suggests many patients did not undergo a preanesthetic airway evaluation, or if they did, it was not documented.
Management plan useful:
The experts suggested it is useful to have a management plan if difficulties are anticipated, and they also recommended documenting the plan on the patient record. In three of the four patients where difficulties were anticipated, there were no plans to modify conventional airway management practice (intravenous induction, administration of muscle relaxants and direct laryngoscopy for placement of a tracheal tube).
In one instance, relying on conventional practice was associated with an immediate loss of the airway on induction, with a late salvage tracheotomy and resulting anoxic brain injury.
In another case, initial conventional management was successful, but the airway was lost at extubation when the patient's trachea was prematurely extubated; conventional practice was unable to re-establish an airway.
On a third occasion, a flexible scope was used to secure the airway while the patient was awake, but no plans were made for enhanced care at the time of tracheal extubation; the result was a failure of conventional practice to re-establish the airway in a timely fashion.
Monitoring equipment valuable:
Pulse oximeters and end-tidal carbon dioxide monitors are regarded as extremely valuable in providing direct evidence for correct tracheal placement of an endotracheal tube (ETCO2 monitor) and reassurance of patient well-being (pulse oximeter).
On at least four occasions, ETCO2 monitors were available and either not used or not relied on when they gave non-reassuring readings. Similarly, in four cases, pulse oximeters were employed, but the response to non-reassuring readings was both delayed and inadequate.
In current airway guidelines, experts advocate using pre-formulated and effective strategies when airway difficulties are anticipated or become evident. They also emphasize the need to maintain oxygenation and to continuously monitor the patient to ensure oxygenation and hemodynamic stability.
Identify the risks
- Do you conduct and document a preoperative airway assessment? Does the assessment require a previous chart and is that chart available?
- Is your assessment reassuring or is this a case where you anticipate a difficult airway?
- Are you, as the physician, and the team prepared to deal with a difficult airway? Is there someone else who could help out and are they available? Do you have the necessary equipment available?
- Do you have adequate monitoring in place and is the team prepared to identify and respond to non-reassuring values?
- Do you recognize and react to any early signs of potential problems?
- Do you provide adequate supervision and support for trainees?
- Have you considered the potential risks associated with extubating the patient's trachea?
- Do you adequately document the clinical care on the patient record?
- Do you inform the patient of any difficulties experienced?