Patrick Brun

Is penicillin G an adequate initial treatment for aspiration pneumonia ? A prospective evaluation using a protected specimen brush and quantitative cultures

ObjectiveTo evaluate the bacteriology of early aspiration pneumonia using a protected specimen brush and quantitative culture techniques, and whether penicillin G is adequate as initial treatment pending culture results.Patients and methods52 patients (of which 45 required mechanical ventilation) meeting usual clinical criteria for aspiration pneumonia were prospectively included. On admission, patients were given intravenous penicillin G and a protected specimen brush was performed ≤48 h after.ResultsCultures of the brush were negative (<103 CFU/ml) in 33 patients (1 had blood cultures positive withS. pneumoniae) and positive (≥103 CFU/ml) forS. pneumoniae in 2 patients. Seventeen patients had a positive culture (≥103 CFU/ml) for at least one penicillin G resistant microorganism, with a total of 20 organisms (S. aureus: 6;H. influenzae: 2;Enterobacteriaceae: 8;P. aeruginosa: 3;C. albicans: 1). In 4 of these patients, a penicillin-sensitive pathogen was also recovered in significant concentrations (S. pneumoniae: 2;Streptococcus sp.: 2). These 17 patients with a resistant pathogen did not differ from the 35 other patients with respect to need for ventilatory support and mortality rate. By contrast, they were older (61.1±21.9 vs 42.9±18.8 years;p<0.005) and required longer mechanical ventilation (6.1±4.6 vs. 3.5±2.7 days;p<0.03) and hospitalization (11.2±8.8 vs. 6.7±4.7 days;p<0.02). Of 17 patients 12 with penicillin G resistant organisms versus 0/35 without, were in-hospital patients and/or had a digestive disorder (p<0.001).ConclusionThe broad range of offending organisms seen in early aspiration pneumonia precludes use of any single empiric regimen, making protected specimen brush mandatory in many patients. Nevertheless, the involvement ofS. pneumoniae in a notable proportion of our patients suggests that routine penicillin prophylaxis after early aspiration (at least in most patients with community-acquired aspiration) is warranted given the potential severity of pneumococcal sepsis in such patients.

Safety, efficacy, and cost-effectiveness of mechanical ventilation with humidifying filters changed every 48 hours: a prospective, randomized study.

Objective: To determine whether three hydrophobic and hygroscopic heat and moisture exchangers (HMEs) retain their heating and humidifying properties (assessed by psychrometric measurements of absolute humidity, relative humidity, and tracheal temperature) for 48 hrs without any drop in their bacteriologic efficiency. Design: Prospective randomized clinical trial. Patients: Sixty‐one consecutive unselected mechanically ventilated intensive care unit patients. Interventions: Patients were randomly allocated to one of the three HMEs studied (Hygrobac‐Dar from Mallinckrodt, n = 21; Humid‐Vent from Gibeck, n = 20; and Clear‐Thermal from Intersurgical, n = 20). Measurements and Main Results: Hygrometric parameters were measured by psychrometry after 3, 24, and 48 hrs of use. Peak airway pressure was recorded every 6 hrs and averaged over 24 hrs. Bacterial colonization of both patients and circuits was studied. Patients in all three groups were similar in terms of age, indications for, and overall duration of mechanical ventilation. Tracheal tube occlusion never occurred. Hygrometric data included 371 measurements whereas bacteriologic data included >700 samples and cultures. The Hygrobac‐Dar HMEs gave a significantly higher absolute humidity whatever the time of measurement (3, 24, or 48 hrs) than the other two HMEs (p < .001). The Clear‐Thermal HMEs gave the poorest hygrometric parameters (p < .01); five of them were replaced prematurely (24 hrs) because the absolute humidity was <25 mg H2O/L. This did not occur for the other HMEs. Mean peak airway pressures were identical in the three groups. The bacterial colonizations of both patient and circuit were similar (and negligible for circuits) for all three groups. Conclusion: Some HMEs may be used safely for 48 hrs without change. However, this does not pertain to every brand of HME. Objective in vivo evaluation of their humidifying performances is decisive before extending their duration of use.