Acute effects of tidal volume strategy on hemodynamics, fluid balance, and sedation in acute lung injury

Objective: To examine the effects of mechanical ventilation with a tidal volume of 6 mL/kg compared with 12 mL/kg predicted body weight on hemodynamics, vasopressor use, fluid balance, diuretics, sedation, and neuromuscular blockade within 48 hrs in patients with acute lung injury and acute respiratory distress syndrome. Design: Retrospective analysis of a previously conducted randomized, clinical trial. Setting: Two adult intensive care units at a tertiary university medical center and a large county hospital. Patients: One hundred eleven patients who were enrolled in the National Institutes of Health ARDS Network trial at the University of California, San Francisco. Interventions: None. Measurements and Main Results: Compared with 12 mL/kg predicted body weight, treatment with a tidal volume of 6 mL/kg predicted body weight had no adverse effects on hemodynamics. There were also no differences in the need for supportive therapies, including vasopressors, intravenous fluids, or diuretics. In addition, there were no differences in body weight, urine output, and fluid balance. Finally, there was no difference in the need for sedation or neuromuscular blockade between the two tidal volume protocols. Conclusions: When compared with ventilation with 12 mL/kg predicted body weight, patients treated with the lung-protective 6 mL/kg predicted body weight tidal volume protocol had no difference in their supportive care requirements. Therefore, concerns regarding potential adverse effects of this protocol should not preclude its use in patients with acute lung injury or the acute respiratory distress syndrome.