Contamination of a Multiple-Use Suction Catheter in a Closed-Circuit System Compared to Contamination of a Disposable,Single-Use Suction Catheter

Multiple-use (M-U) closed-system endotracheal suction catheters are effective in preventing arterial oxygen desaturation in patients on positive end-expiratory pressure (PEEP) and may lessen the frequency of bradycardia and hypotension in unstable patients who are prone to these complications of suctioning. However, because M-U catheters remain attached to the ventilator circuit and are reintroduced repeatedly into the patient's airway over 24 hours or longer, they could become heavily contaminated with pathogens. We hypothesized a risk of autocontamination to the patient by re-inoculation of the respiratory tract with organisms that flourished on the M-U catheter while it was isolated from the patient's immune defenses or antibiotic therapy. Methods: We tested this hypothesis in 30 mechanically ventilated adult patients with positive sputum cultures. We measured and compared the amount of bacteria present on an M-U catheter at the end of a 24-hour use period, the amount of bacteria present in the patient's sputum at that time, and the amount of bacteria present on a single-use (S-U) catheter at that time, after it had made one pass into the patient's airway. Organisms recovered and colony counts were also compared to results of a sputum culture obtained before the study began. Results: Fourteen different pathogens or potential pathogens were recovered, in numbers of 2 × 10¹ to 2 × 10⁷ colony-forming units. The greatest number of colonies was most often recovered from the sputum specimen, and statistical analysis showed no differences in rate or magnitude of contamination between M-U and S-U catheters. We found no clear indication of either increased or decreased risk to the patient from use of an M-U catheter for 24 hours in this study. Further evaluation of the impact of an M-U catheter on the rate and magnitude of colonization of the lung would be useful, considering the potential advantages of this device. (Respir Care 1986;31:1086-1092.)