Publications by authors named "Mary-Anne W Aarts"

3 Publications

  • Page 1 of 1

Empiric antibiotic therapy for suspected ventilator-associated pneumonia: a systematic review and meta-analysis of randomized trials.

Crit Care Med 2008 Jan;36(1):108-17

Department of Surgery, University of Toronto, Toronto, Ontario.

Objective: To compare specific antibiotic regimens, and monotherapy vs. combination therapy, for the empirical treatment of ventilator-associated pneumonia (VAP).

Design: Meta-analysis.

Data Source: Medline, Embase, Cochrane register of controlled trials, study authors, and review articles.

Study Selection: We included randomized controlled trials that evaluated empirical parenteral antibiotic regimens for adult patients with clinically suspected VAP.

Data Selection: Two independent review groups searched the literature, extracted data, and evaluated trial quality. The primary outcome was all-cause mortality; secondary outcomes included treatment failure. Relative risks were pooled using a random effects model.

Results: We identified 41 trials randomizing 7,015 patients and comparing 29 unique regimens. Methodological quality was low, reflecting low rates of complete follow-up (43.9%), use of a double-blinded interventional strategy (14.6%), and randomization concealment (48.6%). Overall mortality was 20.3%; treatment failure occurred in 37.4% of patients who could be evaluated microbiologically. No mortality differences were observed between any of the regimens compared. Only one of three pooled comparisons yielded a significant difference for treatment failure: The combination of ceftazidime/aminoglycoside was inferior to meropenem (two trials, relative risk 0.70, 95% confidence interval 0.53-0.93). Rates of mortality and treatment failure for monotherapy compared with combination therapy were similar (11 trials, relative risk for mortality of monotherapy 0.94, confidence interval 0.76-1.16; and relative risk of treatment failure for monotherapy 0.88, confidence interval 0.72-1.07).

Conclusions: Monotherapy is not inferior to combination therapy in the empirical treatment of VAP. Available data neither identify a superior empirical regimen nor conclusively conclude that available regimens result in equivalent outcomes. Larger and more rigorous trials evaluating the choice of, and even need for, empirical therapy for VAP are needed.
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January 2008

Empiric antimicrobial therapy in critical illness: results of a surgical infection society survey.

Surg Infect (Larchmt) 2007 Jun;8(3):329-36

Department of Surgery, University of Toronto, Toronto, Ontario, Canada.

Background: Antibiotics are prescribed commonly in the intensive care unit (ICU). Often, therapy is initiated empirically; practice patterns are not well characterized. We documented approaches to empiric antibiotic therapy among members of the Surgical Infection Society (SIS).

Methods: We sent a scenario-based questionnaire to all SIS members. The hypothetical cases addressed empiric broad-spectrum therapy for a patient with pyrexia and leukocytosis and the use of vancomycin for central venous catheter infection.

Results: The 113 respondents were primarily surgeons (96%) with a university-based practice (92%). Most attended in the ICU (72%), and they had practiced for 14 +/- 8 years. Whereas 63% of the respondents identified overuse of antibiotics as a problem in their ICU, only 19% said inadequate treatment of infection was a concern. For a febrile patient with negative cultures who was receiving antibiotics, estimates of the likelihood of infection increased across the three scenarios as the degree of organ failure increased (p < 0.0001; chi-square test). Deteriorating organ function was associated with a decision to broaden empiric therapy (58% vs. 33%; p < 0.0001) and to initiate anti-fungal therapy (27% vs. 9%; p < 0.0001) rather than to stop antibiotics and re-culture (15% vs. 51%; p < 0.0001). There was considerable variability in management strategy across the scenarios: Even in the face of organ dysfunction, 58% of physicians would add or change empiric therapy, whereas 30% would not. For each scenario, 23 to 25 antibiotic regimens were designated as optimal therapy. Only 45% of the respondents would initiate empiric vancomycin for suspected central line infection. Variability in approach was not explained by critical care practice, academic position, or country.

Conclusions: Clinical deterioration is a strong determinant of a decision to initiate or broaden empiric antibiotic therapy during critical illness. The substantial variability in approach suggests a state of clinical equipoise that calls for more rigorous evaluation through a randomized controlled trial.
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June 2007

Antibiotic management of suspected nosocomial ICU-acquired infection: does prolonged empiric therapy improve outcome?

Intensive Care Med 2007 Aug 9;33(8):1369-78. Epub 2007 Jun 9.

University of Toronto, Interdepartmental Division of Critical Care Medicine and the Department of Surgery, Toronto, Canada.

Objective: To characterize empiric antibiotic use in patients with suspected nosocomial ICU-acquired infections (NI), and determine the impact of prolonged therapy in the absence of infection.

Design And Setting: Multicenter prospective cohort, with eight medical-surgical ICUs in North America and Europe.

Patients: 195 patients with suspected NI.

Methods: The diagnosis of NI was adjudicated by a blinded Clinical Evaluation Committee using retrospective review of clinical, radiological, and culture data.

Results: Empiric antibiotics were prescribed for 143 of 195 (73.3%) patients with suspected NI; only 39 of 195 (20.0%) were adjudicated as being infected. Infection rates were similar in patients who did (26 of 143, 18.2%), or did not (13 of 52, 25.0%) receive empiric therapy (p = 0.3). Empiric antibiotics were continued for more than 4 days in 56 of 95 (59.0%) patients without adjudicated NI. Factors associated with continued empiric therapy were increased age (p = 0.02), ongoing SIRS (p = 0.03), and hospital (p = 0.004). Patients without NI who received empiric antibiotics for longer than 4 days had increased 28-day mortality (18 of 56, 32.1%), compared with those whose antibiotics were discontinued (3 of 39, 7.7%; OR = 5.7, 95% CI 1.5-20.9, p = 0.005). When the influence of age, admission diagnosis, vasopressor use, and multiple organ dysfunction was controlled by multivariable analysis, prolonged empiric therapy was not independently associated with mortality (OR = 3.8, 95% CI 0.9-15.5, p = 0.07).

Conclusions: Empiric antibiotics were initiated four times more often than NI was confirmed, and frequently continued in the absence of infection. We found no evidence that prolonged use of empiric antibiotics improved outcome for ICU patients, but rather a suggestion that the practice may be harmful.
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August 2007