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.

The glucose error in arterial sampling: assessing staff awareness and the effect of sampling technique.

BACKGROUND: Using a dextrose-containing solution, instead of normal saline, to maintain the patency of an arterial cannula results in the admixture of glucose in line samples. This can misguide the clinician down an inappropriate treatment pathway for hyperglycaemia. METHODS: Following a near-miss and subsequent educational and training efforts at our institution, we conducted two simulations: (1) to observe whether 20 staff would identify a 5% dextrose/0.9% saline flush solution as the cause for a patient's refractory hyperglycaemia, and (2) to compare different arterial line sampling techniques for glucose contamination. RESULTS: (1) Only 2/20 participants identified the incorrect dextrose-containing flush solution, with the remainder choosing to escalate insulin therapy to levels likely to risk fatality, and (2) glucose contamination occurred regardless of sampling technique. CONCLUSION: Despite national guidance and local educational efforts, this is still an under-recognised error. Operator-focussed preventative strategies have not been effective and an engineered solution is needed.