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Continuous subglottic drainage delays onset and reduces incidence of V.A.P.

Citation/s:
Valles J, et al. Continuous aspiration of subglottic secretions in preventing ventilator-associated pneumonia. Ann Intern Med. 1995; 122: 179-186
Lead author's name and fax: Jordi Valles.

Three-part Clinical Question: Does subglottic drainage of secretions prevent ventilator-associated pneumonia in ventilated patients?

Search Terms: critical care; ventilation; subglottic drainage; pneumonia; ventilator- associated pneumonia

The Study: Single-blinded randomised controlled trial without intention-to-treat.

The Study Patients: All patients admitted to a single general ICU who were expected to be ventilated for >72 hours. VAP diagnosed if, after >72 hours: fever; and leukocytosis or leukopenia; and purulent secretions; and new and persistent pulmonary infiltrates; and positive protected specimen brush culture or BAL culture, or good clinical response to antibiotics.

Control group (N = 95; 77 analysed): Intubated with same tube as study group, but additional lumen remained closed. Don't say how often suctioning occurred. All received sucralfate. Did not use SSD or antibiotic prophylaxis. Did not state patient position. Fibreoptic bronchoscopy performed when VAP suspected. Study complete when extubated, or tracheotomy performed, or patient died, or patient developed VAP. Followed up until discharged from ICU or died.

Experimental group (N = 95; 76 analysed): Intubated with tracheal tube with extra dorsal lumen opening just above cuff. Continuous drainage. Other conditions, as above. Don't say how randomisation or blinding performed.

The Evidence:

Comments:
Very significant beneficial effect of an inexpensive intervention in the first week of ventilation. Its impact lessens with time, and no overall significant reduction in ventilator days or ICU mortality

EBM Questions:

1. Do the methods allow accurate testing of the hypothesis? Yes

2. Do the statistical tests correctly test the results to allow differentiation of statistically significant results? Yes

3. Are conclusions valid in light of the results? Yes

4. Did results get omitted, and why? Some patients (28%) who were initially randomised were then excluded because they were intubated for <72 hours, or died, or developed pneumonia within 72 hours.

5. Did they suggest areas of further research? They suggest further studies to examine the usefulness of CASS in specific patient populations such as trauma patients.

6. Did they make any recommendations based on the results and were they appropriate? They recommended the routine use of CASS in the management of intubated patients. This is appropriate.

7. Is the study relevant to my clinical practice? Yes. However, in this study, although overall patients with V.A.P. had longer ICU stays than those without, there was not a statistical difference between the study groups, in duration of ventilation, ICU stay, or ICU mortality.

8. What level of evidence does this study represent? 1⁺

9. What grade of recommendation can I make on this result alone? B

10. What grade of recommendation can I make when this study is considered along with other available evidence? A

11. Should I change my practice because of these results? There is a case for doing so, although the evidence is weak.

12. Should I audit my current practice because of these results? I should audit the rate of VAP in my unit now, then introduce subglottic drainage and then re-audit the rate of VAP.

Appraised by: Joyce Stuart, Western General Hospital, Edinburgh; 13 January 2004

Email: Joyce.Stuart@luht.scot.nhs.uk

Kill or Update By: January 2009  

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