Objective: To study the effect of subglottic secretion drainage (SSD) on the incidence of the ventilator associated pneumonia (VAP) in patients receiving mechanical ventilation.
Methods: A retrospective randomly controlled trial was adopted. From January 2005 to June 2006, patients with an expected duration of mechanical ventilation >48 hours and age >18 years were randomly enrolled as SSD group or control group. The following data were analyzed: age, sex, acute physiology and chronic health evaluation II (APACHE II) score, internal diameter (ID) of artificial airway, duration of enteral nutrition (EN), incidence of VAP, duration of mechanical ventilation, length of intensive care unit (ICU) stay, and the mortality in ICU. In SSD group, the amount of secretion was recorded everyday.
Results: Sixty-one patients were enrolled in the study, 30 patients were randomized to SSD group, and 31 patients were randomized to control group. The two groups were similar in age, sex, APACHE II score, ID of artificial airway, and duration of EN. Compared with control group, the incidence of VAP was significantly lower (30.0% vs. 51.6%, P<0.05), and the duration of mechanical ventilation [(7.9+/-2.6) days vs. (10.4+/-0.9) days] and length of ICU stay [(9.3+/-2.9) days vs. (12.3+/-5.7) days] were significantly shorter in SSD group (both P<0.05), but the time of onset of VAP [(6.5+/-1.3) days vs. (5.5+/-0.6) days] and mortality (26.7% vs. 38.7%) showed no significant difference between two groups (both P>0.05). In SSD group, if 20 ml was supposed to be regarded as an effective criterion for effective drainage on the first day, the incidence of VAP was 8.7% in 23 patients in whom the criterion was reached, and it was 57.1% in 7 patients in whom the amount of drainage was not up to the criterion (P<0.01). The average daily drainage in patients who developed VAP was significantly lower than those who did not develop VAP [(13.3+/-3.3) ml vs. (37.8+/-11.2) ml, P<0.01]. Among all 61 patients, the duration of mechanical ventilation [(12.1+/-4.5) days vs. (6.9+/-2.5) days], length of ICU stay [(14.0+/-5.3) days vs. (8.4+/-2.5) days], and mortality (52.0% vs. 22.2%) were significantly different between VAP patients and patients without VAP (all P<0.01).
Conclusion: Effective SSD is one of the important measures to prevent VAP.