Unintentional endotracheal tube cuff deflation during routine checks: a simulation study

BACKGROUND: Endotracheal tube cuff pressures should be maintained between 20 and 30 cm H2 O to prevent the aspiration of subglottic secretions past the cuff. Guidance recommends regular monitoring of the cuff pressure, performed using a handheld manometer/inflator. Poor technique can lead to transient deflation of the cuff, leading to the bolus aspiration of upper respiratory tract secretions, tracheal colonization and, ultimately, ventilator-associated pneumonia. AIMS AND OBJECTIVES: To determine whether intensive care staff transiently deflate the endotracheal tube cuff to below 20 cm H2 O during routine cuff pressure checks when using a handheld manometer/inflator device. DESIGN: This was an exploratory simulation study. METHODS: A sample of medical (n = 10) and nursing staff (n = 10), capable of caring for a tracheally intubated patient, participated in the study on a single day. A mannequin was intubated with a standard oral endotracheal tube with the cuff pressure set at 50 cm H2 O. Participants were required to check and correct the cuff pressure to the appropriate level with a manometer. The lowest attained and the final target pressures were recorded. RESULTS: Three doctors were unfamiliar with the manometer and did not attempt measurement. During cuff pressure readjustment, 59% (10/17) of participants transiently deflated the cuff below 20 cm H2 O and then re-inflated to attain the final pressure. Of these participants, four deflated the cuff pressure to 0 cm H2 O before re-adjusting it back into range. Most participants, 88% (15/17), corrected the final cuff pressure to between 20 and 30 cm H2 O. CONCLUSIONS: Poor technique when using the manometer led to unintentional cuff deflation during routine checks. In clinical practice, this could increase the risk of pulmonary aspiration and ventilator-associated pneumonia. Further research into alternatives for handheld manometers, such as automated continuous cuff pressure monitors, is warranted. RELEVANCE TO CLINICAL PRACTICE: Cuff deflations can easily occur during routine cuff pressure checks. Staff should be aware of the implications of cuff deflations and seek to improve training with manometers.