Duration of hypotension before initiation of effective antimicrobial therapy is the critical determinant of survival in human septic shock.

Objective: To determine the prevalence and impact on mortality of delays in initiation of effective antimicrobial therapy from initial onset of recurrent/persistent hypotension of septic shock.

Design: A retrospective cohort study performed between July 1989 and June 2004.

Setting: Fourteen intensive care units (four medical, four surgical, six mixed medical/surgical) and ten hospitals (four academic, six community) in Canada and the United States.