Ventilation of patients with acute lung injury and acute respiratory distress syndrome: has new evidence changed clinical practice?

OBJECTIVES: A recent randomized trial of mechanical ventilation in acute lung injury (ALI)/adult respiratory distress syndrome (ARDS) demonstrated a 22% relative reduction in mortality rate using 6 mL/kg predicted body weight tidal volume vs. 12 mL/kg predicted body weight tidal volume. We determined whether publication of these findings changed clinical practice. DESIGN: Retrospective cohort, 12 months before (Pre) and 12 months after publication (Post) of a randomized trial supporting the use of a 6 mL/kg predicted body weight tidal volume strategy. SETTING: Three tertiary care hospitals in northern New England. PATIENTS: From a sample of 943 patients receiving prolonged mechanical ventilation between 1998 and 1999 (Pre) and between 2000 and 2001 (Post), 300 patients meeting the American-European Consensus Conference definition of ALI or ARDS were selected for analysis. INTERVENTIONS: The tidal volume, tidal volume/kg predicted body weight, and proportion receiving tidal volume/kg > or =6 mL/kg and < or =12 mL/kg predicted body weight were recorded at noon the first day after the diagnosis of ALI or ARDS was established. MEASUREMENTS AND MAIN RESULTS: Pre and Post mean tidal volume (+/- sd) size and tidal volume size/kg predicted body weight were 759 +/- 158 mL (median 750 mL) vs. 639 +/- 138 mL (median 600 mL, p <.001) and 12.3 +/- 2.7 mL/kg (median 11.7 mL/kg) vs. 10.6 +/- 2.4 mL/kg (median 10.7 mL/kg, p <.001) respectively. Pre and Post plateau pressures and peak airway pressures were similar. CONCLUSION: Publication of a trial demonstrating large mortality reductions using small tidal volume was associated with significant reductions in tidal volume delivered to patients with ALI/ARDS. However, wide variation in practice persists, and the proportion of patients receiving tidal volumes within recommended limits (< or =8 mL/kg) remains modest.

Successful meropenem desensitization in a patient with cystic fibrosis.

OBJECTIVE: To report a case of successful meropenem desensitization in a patient with cystic fibrosis (CF) with documented hypersensitivity to multiple antibiotics including carbapenems. CASE SUMMARY: A 20-year-old white man with CF was admitted to the hospital for treatment of an acute pulmonary exacerbation caused by multidrug-resistant Burkholderia cepacia complex and methicillin-resistant Staphylococcus aureus (MRSA). Past treatments of his CF exacerbations were complicated by urticarial eruptions following administration of beta-lactams, including meropenem, and ototoxicity from aminoglycosides. Skin testing revealed hypersensitivity reactions to beta-lactam antibiotics including penicillin, piperacillin/tazobactam, ceftazidime, and imipenem. A literature review (MEDLINE, January 3, 2002) and communication with the manufacturer of meropenem revealed no specific information on desensitizing patients to this agent. Because of meropenem's activity against B. cepacia complex alone and in combination with other antimicrobials, a desensitization protocol was adapted and applied to meropenem in an effort to provide the most beneficial treatment available. A 12-dose escalation protocol was successfully employed without incident. DISCUSSION: Antimicrobial therapy is limited in CF patients by susceptibility profiles of common infecting organisms (e.g., Pseudomonas spp., B. cepacia complex, MRSA). Unfortunately, host responses may further reduce the utility of many effective antibiotic classes due to hypersensitivity and/or adverse reactions. Desensitization is a useful alternative that allows the administration of beneficial medications to patients with documented allergy histories. CONCLUSIONS: Meropenem is an important treatment option in the CF population, particularly due to its activity against B. cepacia complex. Successful desensitization using a dose-escalation protocol in patients with a documented carbapenem allergy will allow the most beneficial therapy to continue.