ABSTRACT & COMMENTARY
Subglottic Secretion Suctioning Reduces Vent-Associated Pneumonia, Antibiotic Use
Should subglottic suctioning be added to VAP prevention bundles?
By Richard R. Watkins, MD, MS, FACP
Division of Infectious Diseases, Akron General Medical Center, Akron, OH; Associate Professor of Internal Medicine, Northeast Ohio Medical University, Rootstown, OH.
Dr. Watkins reports no financial relationships in this field of study
SOURCE: Damas P, et al. Prevention of Ventilator-Associated Pneumonia and Ventilator-Associated Conditions: A Randomized Controlled Trial With Subglottic Secretion Suctioning. Crit Care Med. 2014 Oct 23. [Epub ahead of print]
Ventilator-associated pneumonia (VAP) is a serious complication for intubated patients. It causes significant morbidity and mortality, increases healthcare costs and is the main reason for antibiotic use in the intensive care unit (ICU). Thus, strategies that reduce the incidence of VAP would greatly benefit both patients and the healthcare system. Previous studies have shown that suctioning subglottic secretions in ventilated patients can reduce VAP. Damas and colleagues sought to determine whether subglottic secretion suctioning would be effective in reducing VAP at a tertiary center where a prevention bundle was in place, as well as reducing overall antibiotic usage.
The study enrolled patients hospitalized in one of the ICUs at the University Hospital of Liege between January 23, 2012 and March 31, 2013 who were intubated with a particular endotracheal tube (Teleflex Isis ) that permitted subglottic secretion suctioning. Patients were randomized to two groups, group 1 received subglottic secretion suctioning (experimental) and group 2 did not (control). The institution had a VAP bundle in place since 2009 that included semirecumbent positioning of at least 30°, oral care that included teeth brushing with 0.2% chlorhexidine and application of 1% chlorhexidine gel, control of cuff pressure of the endotracheal tube between 20 and 30 cm H2O, and daily assessment of sedation. All randomized patients were screened daily for the occurrence of VAP.
The diagnosis was suspected by clinical criteria including a new infiltrate on chest radiograph, fever or hypothermia, leukocytosis or leukopenia, purulent tracheal secretions and worsening of oxygenation. VAP was confirmed by quantitative bacterial culture of >106 CFU/mL from an endotracheal specimen of >104 CFU/mL from bronchoalveolar lavage fluid. The primary endpoint was the occurrence of VAP in the experimental and control groups. The secondary endpoints were the occurrence of ventilator-associated conditions (VAC) and infection-related ventilator-associated complications (IVAC), as well as the proportion of antibiotic days during ICU stay.
A total of 352 patients were randomized, 170 to group 1 and 182 to group 2. After 48 hours of ventilation, VAP was suspected in 27 and confirmed in 15 patients (8.8%) in group 1 while it was suspected in 41 and confirmed in 32 patients (17.6%) in group 2 (P = 0.018). Subglottic secretion suctioning resulted in an event reduction of 8.8%, indicating that 9 episodes of VAP could be avoided for every 100 intubated patients. Furthermore, logistic regression analysis showed the protective role of subglottic suctioning (OR = 0.45; 95% CI, 0.24-0.87) and that none of the potential confounding variables identified impacted the significance of suctioning. Regarding the secondary endpoints, VAC and IVAC prevalence were comparable between the two groups (P = 0.56 and 0.47, respectively). During the entire ICU stay, antibiotics were given a median of 7 days in group 1 and 8 days in group 2 (P = 0.45). The total number of antibiotic days was significantly lower in group 1 (1,064) compared to group 2 (1,222) (P = 0.001) and more patients in group 1 had no days on antibiotics (16.4%) compared to group 2 (7.4%) (P = 0.02). Finally, the length of ICU stay, duration of mechanical ventilation, tracheostomy rate, ICU mortality and hospital mortality did not differ significantly between the two groups.
COMMENTARY
The results from this randomized trial show that suctioning of subglottic secretions significantly reduces VAP and antibiotic consumption. While these findings are noteworthy, the study did have a few limitations. First, it was conducted at a single center so the results might not apply to other settings. Second, it was not possible to blind the control and experimental groups. Third, only patients with a particular type of endotracheal tube were enrolled in the study. Finally, the overall number of VAP cases was relatively small. Nevertheless, there were no reported complications of subglottic suctioning and the observed reduction in antibiotic consumption is important from an antibiotic stewardship perspective.
The widespread adoption of prevention bundles in the U.S. over the past few years has led to a substantial decrease in the rate of VAP (1 to 3 episodes/1,000 ventilator days). Although VAP has not declined as much in Europe (12-18 episodes/1,000 ventilator days) as the U.S., this may be due to differences in how VAP is defined. Indeed, a frequent criticism of studies on VAP is that the definition of VAP remains controversial. It would therefore be useful to researchers and clinicians alike if a universal definition of VAP could be agreed upon and widely adopted.
The findings from the study by Damas and colleagues support previous data that also showed the benefit of subglottic secretion suctioning. Although it seems reasonable to add subglottic secretion suctioning to VAP prevention bundles, it will likely take another randomized clinical trial from North America to also show a significant benefit before this intervention becomes widely implemented in American ICUs.
