Impact of subglottic suctioning on the incidence of pneumonia after cardiac surgery: a retrospective observational study

Objective: Continuous aspiration of subglottic secretions (CASS) has been found to decrease the incidence of pneumonia in the general intensive care unit (ICU) population, but its benefit in cardiac surgery patients is unclear. The present study aimed to determine whether the routine use of CASS in cardiac surgical patients was associated with decreased pneumonia.

Design: A retrospective, single-center observational study.

Setting: The study was conducted in a quaternary care cardiac surgery center and university research hospital.

Participants: 4,880 patients undergoing cardiac surgery were studied.

Interventions: The control group (no CASS) received a standard endotracheal tube and underwent surgery between April 1, 2007 and March 31, 2009. The intervention group (CASS) received a subglottic suctioning endotracheal tube and underwent surgery between June 1, 2009 and May 31, 2011. The primary outcome was the development of pneumonia, and the secondary outcomes were 30-day in-hospital mortality, ventilation time, need for tracheostomy, ICU length of stay (LOS), and hospital LOS.

Measurements and main results: The unadjusted incidence of pneumonia was 1.9% in the CASS group and 5.6% in the control group (p<0.0001). The CASS group also had lower 30-day in-hospital mortality (2.1% v 3.3%; p = 0.007), median ventilation time (8.42 v 7.3 hours; p<0.0001), and shorter median ICU LOS (1.77 v 1.17 days; p<0.0004) compared with the control group. Tracheostomy rates and median hospital LOS did not differ between groups. After adjusting using multivariable modeling, CASS remained an independent risk predictor for pneumonia (odds ratio [OR] 0.342, 95% confidence interval [CI] 0.239-0.490) and ICU LOS (OR 0.817, 95% CI 0.718-0.931).

Conclusions: The universal implementation of CASS in a quaternary care cardiac surgical population was associated with a decreased incidence of pneumonia.