Dr. Lewis’ clinical interests have centered on trauma and critical care, and his research has focused on cardiopulmonary physiology, cardiopulmonary effects of sepsis, and acute respiratory failure. He collaborated with Virgil Elings, MD, University of California, Santa Barbara, to develop the lung water computer, which allowed the quantitation of pulmonary edema using the double indicator technique. They established the validity of the technique in both human and animal models.

Dr. Lewis’ more recent work has focused on critical care physiology and specifically the cardiopulmonary effects of sepsis and of vascular resistance on cardiac output.