Humidification during mechanical ventilation to prevent endotracheal tube occlusion in critically ill patients: A case control study.

BACKGROUND

Endotracheal tube (ETT) occlusion is a potentially life-threatening event. This study describes a quality improvement project to prevent ETT occlusion in critically ill patients.

METHODS

After a cluster of clinically significant ETT occlusion incidents at a tertiary-care intensive care unit (ICU), the root cause analysis suggested that the universal use of heat moisture exchangers (HMEs) was a major cause. Then, we prospectively audited new ETT occlusion incidents after changing our practices to evidence-based active and passive humidification during mechanical ventilation (MV). We also compared the outcomes of affected patients with matched controls.

RESULTS

During 100 weeks, 18 incidents of clinically significant ETT occlusion occurred on a median of 7 days after intubation (interquartile range, 4.8-9.5): 8 in the 10 weeks before and 10 in the 90 weeks after changing humidification practices (8.1 vs. 1.0 incidents per 1000 ventilator days, respectively). The incidents were not suspected in 94.4%, the peak airway pressure was >30 cm HO in only 25%, and 55.6% were being treated for pneumonia when ETT occlusion occurred. Compared with 51 matched controls, ETT occlusion cases had significantly longer MV duration (median of 13.5 vs. 4.0 days; = 0.002) and ICU stay (median of 26.5 vs. 11.0 days; = 0.006) and more tracheostomy (55.6% vs. 9.8%; < 0.001). The hospital mortality was similar in cases and controls.

CONCLUSIONS

The rate of ETT occlusion decreased after changing humidification practices from universal HME use to evidence-based active and passive humidification. ETT occlusion was associated with more tracheostomy and a longer duration of MV and ICU stay.