Continuous versus intermittent endotracheal tube cuff pressure control for the prevention of ventilator-associated pneumonia: A focused systematic review and exploratory meta-analysis

ABSTRACT

Continuous endotracheal tube cuff pressure control is intended to maintain cuff pressure within the recommended range, reduce microaspiration, and prevent ventilator-associated pneumonia (VAP). However, randomized trials have produced apparently inconsistent findings. The clinical question is therefore not only whether continuous control lowers VAP overall, but also why physiologic benefits have not translated consistently into patient-important infection outcomes. We performed a focused systematic review and evidence synthesis of randomized studies comparing continuous versus intermittent endotracheal tube cuff pressure control in critically ill adults. Trial characteristics, comparator intensity, endpoint definitions, risk-of-bias considerations, and directly extractable outcome data were reviewed from the original reports. Because the included studies used non-identical primary outcomes, the primary synthesis was qualitative. Exploratory random-effects meta-analyses were restricted to outcomes with directly extractable binary event counts. Five randomized studies involving 1,355 analyzed patients were included. Early single-center studies suggested that continuous cuff pressure control improved cuff pressure stability, reduced microaspiration-related markers, and in some settings lowered infection-related endpoints. In contrast, the two largest later multicenter trials did not demonstrate a consistent reduction in VAP or ventilator-associated respiratory infection (VARI). An exploratory pooled analysis of four studies with directly extractable VAP-like binary outcomes showed no statistically significant reduction with continuous control (risk ratio 0.89, 95% confidence interval 0.63–1.24; I ² = 55.8%). A sensitivity analysis using the Vietnam trial’s primary VARI endpoint rather than VAP yielded a similar result (risk ratio 0.92, 95% confidence interval 0.67–1.28; I ² = 57.7%). Exploratory pooled intensive care unit (ICU) mortality across all five studies was also not significantly different (risk ratio 0.91, 95% confidence interval 0.77–1.07; I ² = 0%). Continuous cuff pressure control improves cuff pressure stability and may reduce microaspiration-related markers, but current randomized evidence does not demonstrate a consistent overall reduction in clinically important infection outcomes across diverse ICU settings. The apparent inconsistency in the literature is best explained by differences in endpoint choice, comparator intensity, timing of intervention, baseline preventive practices, and patient population. Continuous control should therefore be regarded as a context-dependent adjunct rather than a universally proven stand-alone VAP-prevention strategy.