Benchmarking the Applicability of Four Methods of Endotracheal Tube Cuff Inflation for Optimal Sealing: A Randomized Trial

Upper airway tract complications of endotracheal intubation

The gold standard in airway maintenance is translaryngeal endotracheal intubation, but this is not without its complications. Trauma to the upper airway as a result of the act of endotracheal intubation is a common event in adults undergoing procedures under general anaesthesia. Sites requiring attention during intubation include the laryngeal apparatus, the pharynx and oral cavity as well as the nasal cavity when nasopharyngeal intubation is performed. Patients can present with a range of symptoms which can make assessment and management challenging. Dysphonia, throat pain and dysphagia are the commonest presenting complaints. Patient-related factors, intubation technique and other anaesthetic-related conditions can be a cause of trauma, if not adequately considered before intubation. All patients should be carefully examined preoperatively and their past medical history obtained. Patient demographics, comorbidities, existing airway pathology and presence of reflux should be noted. Trauma prevention strategies should be in place to eliminate avoidable complications. Potential difficult airway cases should be flagged up and adequately prepared for, in anticipation of intubation difficulties that can lead to trauma. The majority of injuries will resolve spontaneously with conservative management. Persistent symptomatology, usually secondary to laryngeal injuries, requires prompt referral to an ear nose and throat specialist with an interest in laryngology for further assessment and treatment.

Accuracy of the minimal leak test for endotracheal cuff pressure monitoring

OBJECTIVES

To determine the accuracy of the minimum leak test as a surrogate for target endotracheal cuff pressure of 20-30 cm H₂ O in intubated patients.

METHODS

Cuff pressures were measured at the University of Miami Hospital using the minimum leak test on every intubated patient once per shift, then cuff pressure was reevaluated using handheld numerical manometers and recorded pressures above or below the target range, readjusting the pressure as needed. This assessment was repeated throughout each patient's intubation for up to 6 days. The readjustment rate of the test and the probability of a patient needing at least one adjustment were determined.

RESULTS

One hundred twenty-two patients were evaluated. Median age was 67 years (range 29-95), 52% were male, 48% were female. Patients were followed for an average of 4.7 days. Seven hundred twenty-two minimum leak tests were performed. Of these, 170 required readjustment into the target range (24% readjustment rate). Of the tests outside target range, 66% of cuffs were overinflated and 34% were underinflated. Fifty-five percent of patients required at least one adjustment.

CONCLUSION

Despite ubiquitous use of the minimum leak test for endotracheal cuff pressure adjustment, the test has an unacceptably high error rate resulting in cuff pressures above or below the target range. Most patients will require at least one adjustment throughout an intubation, putting them at risk for tracheal injury, stenosis, or leak and aspiration. The minimum leak test is not sufficiently accurate for endotracheal cuff pressure monitoring. Formal manometry is superior and should be used to optimize patient outcomes.

LEVEL OF EVIDENCE

4 Laryngoscope, 130:1646-1650, 2020.