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Airway obstruction in the postanaesthetic care unit of a tertiary care centre

A prospective audit

Curtis, William; Sethi, Rajesh; Visvanathan, Thavarajah

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European Journal of Anaesthesiology (EJA): June 2015 - Volume 32 - Issue 6 - p 444-446
doi: 10.1097/EJA.0000000000000227
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Airway obstruction in the immediate postoperative period can pose a threat to patient safety.1 The fourth National Audit Project of the Royal College of Anaesthetists showed that airway obstruction was a major contributor to airway-related complications.2

The purpose of this prospective audit was to assess the incidence and to quantify the severity and outcomes after airway obstruction in the recovery room of a tertiary care hospital. We also aimed to make recommendations for improvement in practice. Prior to the completion of this study, there were no data available for comparison at our institution.

The Royal College of Anaesthetists proposes that less than 5% of postoperative patients should require airway support in postanaesthetic care unit (PACU), with less than 1% needing re-intubation of their trachea.3

Over a 2-month period, all patients admitted to PACU from the operating rooms were included in the audit. The study group comprised adult patients undergoing orthopaedic, urologic, thoracic, gynaecologic, vascular, upper gastrointestinal, colorectal, plastic or otorhinolaryngologic (ENT) surgical procedures. Patients undergoing day surgical procedures were excluded from the study. Being a quality assurance project, formal approval from the ethics committee was not required (Human Research and Ethics Committee, The Queen Elizabeth, Lyell McEwin & Modbury Hospitals, Chair: Dr Timothy Matthew, 15 September 2014).

In the operating room, demographic data, anaesthetic technique and airway adjuncts (if utilised) were noted. Conscious state on arrival, episodes of airway obstruction or apnoea, need for airway support and outcomes were recorded in PACU.

Airway obstruction was identified by the presence of heavy snoring, choking4 or presence of a tracheal tug with paradoxical breathing, that was responsive to simple airway interventions. Apnoea was defined as absence of airflow at the mouth for more than 10 s.4 Airway obstruction was classified as mild (normal oxygen saturation) (SpO2), moderate (SpO2 <94%), severe (SpO2 <90%) or laryngospasm. The presence of inspiratory stridor with paradoxical chest and abdominal movements,5 not responsive to simple airway manoeuvres, was used to identify laryngospasm. Standard patient care guidelines6 were adhered to at all times.

Complete data were collected on a total of 486 patients. Endotracheal tubes were preferred over supraglottic airway devices in the study population (57.4% as compared with 39.7%). Out of a total of 405 airway adjuncts, the majority of devices (84%) were removed in the operating room. More than two-thirds of the patients were alert and responsive to verbal commands or pain on arrival in PACU.

The overall incidence of airway obstruction was 30.8%, with only 16 patients (3.2%) encountering a drop in SpO2 to less than 94%. Forty-five patients (9.2%) required airway support in PACU, whereas one patient required tracheal reintubation secondary to haemodynamic instability (Table 1). The median duration of stay in PACU was 50 min [interquartile range (IQR) 40 to 70]. Less than 1% of the patients had a prolonged stay in PACU related to respiratory causes.

Table 1
Table 1:
Airway audit summary

The incidence of airway obstruction is significantly high in our study as compared with other studies.7 This is possibly due to the stringent definitions and classification employed, thereby enabling us to identify even the mildest of obstructions. Unfortunately, there is no common consensus on standard definitions of airway obstruction in the perioperative setting.

Although two-thirds of our patients were responsive on arrival in PACU, we still fell short of the benchmark in current practice in terms of requirement for airway support. Our figure of 9.2% is almost twice that of the Royal College of Anaesthetists recommended standards.3 This may reflect the need for a potential change in our practice, leading to more patients arriving awake and responsive in PACU. Depressed level of consciousness may be associated with an increased need for airway support.8,9

We observed a high number of minor airway events (airway obstruction with normal SpO2), in addition to one episode of laryngospasm and only one major adverse event (tracheal re-intubation in PACU). The observed results are probably a reflector of the quality of care provided to our patients (in accordance with set standards),6 which led to an early detection and treatment of obstructions at an initial stage, thereby reducing the incidence of major adverse and potentially catastrophic events.

Quality improvement projects have traditionally meant to focus on major adverse events (such as hypoxemia with SpO2 <90% or respiratory failure). However, we believe that if problems such as airway obstruction are recognised and treated at an early stage, a significant amount of morbidity and possibly mortality can be prevented. This would help improve the quality of care delivered to patients, in addition to healthcare cost savings. In the contemporary financially insecure atmosphere with ever-shrinking healthcare budgets, a change in practice, thereby targeting minor adverse events, with an aim to prevent major incidents may be highly warranted on a priority basis.

Lack of data on weight, BMI and smoking status are limitations of this audit. However, an increased incidence of airway complications with these conditions is a known entity.

On the basis of our data, we suggest that staff education is of paramount importance for early recognition of airway obstruction. A modification in anaesthetic practice, with an aim to transfer patients awake or minimally sedated to PACU, may lead to a reduction in the incidence of respiratory complications. Increased incorporation of regional anaesthesia into our day-to-day practice could be helpful in achieving our goals, in addition to an added benefit of a reduced incidence of nausea and vomiting.10 Introduction of an ‘extubation checklist’ may be helpful to identify patients at risk for tracheal re-intubation.

Acknowledgements relating to this article

Assistance with the audit: none.

Financial support and sponsorship: none.

Conflicts of interest: none.


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