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.

Accidental dual humidification in intensive care units: Repeated alerts and system changes are not enough.

PURPOSE: The inadvertent, simultaneous use of heat and moisture exchangers (HMEs) and heated humidifiers (HHs) can result in waterlogging of the filter and sudden ventilation tube occlusion, with potentially fatal consequences. Following an NHS England Safety Alert, a near miss and educational reminders in our institution, we introduced new guidelines to solely use HHs in the intensive care unit and HMEs only for patient transfers. No further incidents have occurred, however this solution is potentially fallible. Two years later, we sought to assess staff knowledge and likelihood of recognising this error should it occur. MATERIALS AND METHODS: In a simulation study, a tracheally intubated and ventilated mannequin had a breathing circuit containing both a HME and a HH. Participants were asked to assess the circuit, identify errors and undertake corrective measures. RESULTS: Only 30% (6/20) recognised and undertook corrective measures. CONCLUSIONS: Despite educational efforts and system changes, recognition of this error remained poor. System changes may reduce the likelihood of the error occurring, but when it does, recognition may not occur. Substantial reductions or elimination of this error may be achieved through a safety-engineered fail-safe within the equipment, which alerts staff to improve recognition and prevent the mistake.