Protective effect of antibiotic prophylaxis against early-onset nosocomial pneumonia in comatose patients

Objective

To study the impact of prophylactic antibiotics on the occurrence of early-onset nosocomial pneumonia in patients with medical coma.

Patients and methods

An open, before and after, single-center trial, in the medical ICU of the University Hospital of Besancon, France. A first period (A, retrospective) extended during 18 months (April 2003–October 2004) without antibiotic prophylaxis and was followed by a second period (B, prospective) during 18 months (November 2004–April 2006). Patients received prophylaxis treatment by amoxicillin and clavulanic acid, shortly after intubation and during a 24-hour period. Inclusion criteria were medical loss of consciousness, Glasgow Coma Score < 8, and length of intubation > 48 hours.

Results

A total of 101 patients were enrolled, 61 patients during period A and 40 patients during period B. No significant differences were found between mean age (48.6 years vs 50.4 years old), SAP II score (44.5 vs 46.5), aetiology of coma (mainly ischaemic stroke, cardiac arrest, refractory epilepsy, intoxication), and early-onset (n = 12 vs n = 6) or late-onset pneumonia (n = 1 vs n = 2). During period B, the time for onset of colonisation (6.6 days vs 3 days, P = 0.008) or pneumonia (8.4 days vs 4.2 days, P = 0.03) was increased compared with period A. We did not diagnose multidrug-resistant infection or colonisation. No difference was found with regard to mortality and morbidity: duration of mechanical ventilation (5.7 days vs 6.7 days) or total hospitalisation stay (26.6 days vs 16.9 days), total mortality (n = 9 vs n = 10 patients) or at day 28 (n = 6 vs n = 7 patients), respectively, in periods A and B. In multivariate analysis, tobacco, cardiac arrest and ischaemic stroke were independent risk factors of pneumonia.

Conclusion

In our study, contrary to previous ones [1, 2], antibioprophylaxy did not show a decrease in the incidence of nosocomial pneumonia in medical comatose patients with Glasgow Coma Score < 8 under mechanical ventilation. On the other hand, antibiotics induce a later onset of colonisation and lung infections. Despite a prevention of early-onset nosocomial pneumonia, our data do not support the use of regular prophylactic antibiotics.