REJECTION CRITERIA FOR ENDOTRACHEAL ASPIRATES FROM PEDIATRIC-PATIENTS

Endotracheal aspirates (ETAs) from mechanically ventilated pediatric p atients frequently are cultured as part of an evaluation for suspected sepsis. There are now well-defined criteria for rejecting low-yield E TAs from adults, but it is uncertain whether the same criteria can be applied to ETAs from children. Therefore, we compared the Gram stain a nd culture results for 361 consecutive ETA specimens collected from pe diatric patients over a 1-year period. Results for patients for whom a blood culture was performed within 48 h of the time that a culture of ETA was performed were also reviewed. Gram stains were examined under x100 magnification to quantitate the number of polymorphonuclear neut rophils and squamous epithelial cells (SECs) per low-power field and u nder x1,000 magnification for the presence of organisms. No organisms were seen by Gram staining in 225 (62%) of the ETAs. Culture of these specimens rarely yielded useful information: 52% were sterile, 32% gre w rate to 1+ quantities of expected respiratory flora only, 12% grew r are to 1+ quantities of gram-negative rods mixed with expected respira tory flora, and only 10 (4%) yielded a pure of predominant growth of a potential respiratory pathogen. Unlike adult patients, we did not fin d the number of SECs to be a useful screening criterion. Only 17 (5%) of the ETAs had greater than 10 SECs per low-power field, and 5 (29%) of these yielded pure growth of a gram-negative rod. When blood cultur e results were positive, they correlated with ETA culture results in o nly 6 of 10 cases. On the basis of our findings, the absence of organi sms on Gram staining is a useful criterion for rejecting ETAs from ped iatric patients for culture and would have excluded 62% of the specime ns from further processing.