2000 OPEN FORUM Abstracts
THE EFFECT OF BLIND PROTECTED SPECIMEN BRUSH SAMPLING ON ANTIBIOTICS USAGE IN PATIENTS WITH SUSPECTED VENTILATOR ASSOCIATED PNEUMONIA
Paul E. Marik, MD, FCCM; Joseph Lynott, MS, RRT; Michelle Croxton, MT(ASCP)SM Edward Palmer, RRT; Larry Miller, RRT and Gary P. Zaloga, MD, FCCM Division of Critical Care Medicine, Respiratory Services and Microbiology, Washington Hospital Center, Washington, DC
Background: The diagnosis of pneumonia in ventilated patients is exceedingly difficult. Although culture of tracheal aspirates have poor diagnostic value they are frequently used to diagnose ventilator associated pneumonia (VAP). Recently, a number of studies have reported on the diagnostic value of "blind" protected specimen brush (B-PSB) sampling in the diagnosis of VAP. B-PSB can readily and safely be performed by Respiratory Care Practitioner's (RCP's). The aim of this study was to determine the cost-effectiveness of B-PSB sampling performed by RCP's in patients with suspected VAP.
Methods: During a three month run in period, patients in our MICU with suspected VAP were treated based on clinical criteria and tracheal-aspirate culture. Following this run in period the house-staff, nurses and RT's were prevented from sending tracheal aspirates for culture. All patients suspected of having ventilator associated pneumonia underwent B-PSB sampling with quantitative culture. The B-PSB sampling was performed by RCP's who had been trained to perform the technique. A PSB with a potential bacterial pathogen in a concentration >500 CFU/ml was regarded as positive.
Results: During the 3 month run in period 172 patients received mechanical ventilation with an average of 4.9 ± 3.1 ventilator days/patient. During this period 79 patients were treated for VAP. During the 3 month study period 160 patients received mechanical ventilation with an average of 5.1 ± 2.9 ventilator days per patient (NS). 58 B-PSB samplings were performed in 50 patients for suspected VAP. No complications related to the procedure were reported. No tracheal-aspirates were cultured during this time period. Eight patients had positive PSB cultures. Antibiotics were changed in 3 of these patients based on the PSB results. Thirty-eight courses of antibiotics (in 36 patients) were stopped based on negative PSB results. Twelve cases of VAP were suspected in 6 patients receiving antibiotics for other reasons. No change in antibiotics were made in these cases based on negative PSB results. The length of mechanical ventilation was 5.4 ± 3.2 days in the 38 culture negative patients in whom antibiotics were stopped compared to 8.2 ± 4.7 days in the eight patients with PSB positive VAP (NS; p=014s). The direct cost savings, as a result of discontinuing antibiotics was $9500. There were additional cost savings due to the reduced number of culture specimens sent to the lab (approximately $2,000), with a projected annual cost saving of $46,000.
Conclusion: B-PSB sampling is a simple and cost efficient diagnostic test that can safely be performed by RCP's. Furthermore, this study confirms that antibiotics may be safely discontinued in patients with negative quantitative culture results.