[Respiratory circuits and infections of the airway].
OBJECTIVE
To study the effects of ventilator circuit changes on the rate of airway infections and to investigate the relationship between the microorganisms responsible for circuit colonization and those responsible for infection.


METHODS
Prospective study, carried out in two different periods, of one year duration each.


METHODS
General Intensive Care Units (ICUs) in a University Hospital.


METHODS
Seventy-eight patients, requiring mechanical ventilation (VAM) for more than 5 days, were enrolled. They were divided into two groups: in the first (group I, n. 36, 1st period) the ventilator circuit was changed every 5 days; in the second (group II, n. 42, 2nd period) every 10 days.


METHODS
Ventilator circuit change every 5 or 10 days. Daily culvert and filling of cascade humidifiers with sterile irrigation water. Daily replacement of mount catheter.


METHODS
Qualitative cultures of tracheobronchial aspirate and of fluid from the humidifying cascades and the expiratory tubing traps.


RESULTS
The two groups were similar. Pneumonia and tracheobronchitis were found in the 25% and 11% of patients of group I and in 26% and 12% of those of group II respectively. The VAM duration was 26.5 +/- 15 days in patients who developed airway infection, and 12.9 +/- 11.6 days (p < 0.001) in patients who did not. The Gram+ organisms were predominant. An identical microorganism was found both in the tracheo-bronchial aspirate and in the circuit in 44 of 78 (56%) patients; no difference was found between infected (16 of 29) and non infected (28 of 49) patients.


CONCLUSIONS
Changing the ventilator circuit every 10 days rather than every 5 days, does not increase the incidence of airway infections and result in considerable savings in the expenses of tubing and personnel time. The infection or colonization rates due to the same microorganisms are quite low and it seems not useful to make routine cultures of fluid from humidifying cascades and the expiratory tubing traps in order to characterize in time the microorganism that could be responsible of airway infections.
Verri
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Istituto di Anestesiologia e Rianimazione, Università degli Studi, Ferrara.
Capuzzo
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Rossi
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Alvisi
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Ragazzi
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Gritti
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D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D008297:Male; D012121:Respiration, Artificial / Q000009:adverse effects* / Q000295:instrumentation; D012141:Respiratory Tract Infections / Q000209:etiology*; D012122:Ventilators, Mechanical / Q000009:adverse effects*