Is disinfection of mechanical ventilation tubing needed at home?

Introduction: Home mechanical ventilation is used to treat chronic alveolar hypoventilation. Maintenance protocols for home ventilation circuits (HVC) remain empirical and unproven. We have investigated (1) the cleanliness and sterility of the HVC used by home ventilated patients and (2) the efficiency of tubing cleaning and decontamination protocols recommended to them and used for 12 months or more.

Method: HVC cleanliness was assessed in 39 severe restrictive ventilated patients (16 (T) tracheostomy vs. 23 (N) noninvasive) and in 7 new valves as control. In the first experiment (Exp1), a visual and bacteriologic inspection of the expiratory valve (Eva) was conducted during a consultation in our centre. Eva visual cleanliness was assessed on a 10-point scale and Eva bacteriologic contamination analysis was performed on a dry smear. In the second experiment (Exp2), these analyses were repeated after a cleaning sequence chosen at random, either chemical (ammonium-chlorhexidine complex) (A) or mechanical by dishwasher (B).

Results: In Exp1, 69% of Eva were dirty. Dirtiness was worse in (T) than in (N) (5.3 vs. 2; p<0.001). There was a significant positive correlation between visual cleanliness and bacteriologic contamination (r=0.56; p<0.001). Eva in group (T) were more contaminated than in group (N) (p<0.001). Eva contamination rates reached 22% in group (N) but without the presence of any potentially pathogenic organisms (PPO) and 81% in group (T) where 19% were PPO. In Exp2, EVA visual cleanliness was better after dishwasher cleaning (B) compared to chemical (A) (0.16 vs. 1.05; p<0.001) with similar bacteriological decontamination.

Conclusion: HVC from noninvasive ventilated patients are dirty but not contaminated by PPO. We recommend washing them in a dishwasher or with detergent and hot water without specific disinfection. PPO contaminated 1/5 of invasive HVC, for which we recommend dishwasher cleaning. Decontamination is only indicated when tubing is visually very dirty or/and when tracheostomized patients are particularly sensitive to respiratory tract infections. The expiratory valve must be carefully washed specifically, with care that its balloon is not placed under water.