Objective: To assess the frequency and mortality rates of septic shock in ICU patients and the clinical course of multiple organ failure associated with septic shock.
Design: Retrospective case survey.
Setting: Tertiary care center.
Patients: During a 2-yr period, 2,469 consecutive intensive care patients were studied regarding the frequency and hospital mortality rates of septic shock. A subset of 1,311 patients was further analyzed for the occurrence of organ system failures within 48 hrs of the onset of septic shock and again 4 to 7 days later.
Measurements and main results: The frequency rate of septic shock was 1.9% (n = 48), with a mortality rate of 72.9% (n = 35) in patients with septic shock. Deaths due to septic shock represented 14.6% of all deaths in the ICU during the study period. Eighteen patients died within 72 hrs of the onset of septic shock. Refractory hypotension was the cause of death in 15 of these 18 patients. Beyond 72 hrs, multiple organ failure accounted for eight of 17 deaths. The mean +/- SD number of organ systems failing at 48 hrs was 3.3 +/- 1.3 in survivors and 4.0 +/- 1.1 in nonsurvivors, and at 4 to 7 days was 2.1 +/- 1.5 in survivors and 4.0 +/- 1.5 in nonsurvivors (p less than .05). None of the specific organ system failures had prognostic value. The number of organ system failures was not related to the duration of hypotension, but had a weak correlation (r2 = .26, p less than .05) with the duration of vasoactive treatment at 4 to 7 days. The prolonged need for norepinephrine therapy was associated with an increased occurrence of renal failure. Thirty (62.5%) patients had positive blood cultures and a mortality rate similar to the mortality rate of patients with negative blood cultures. Patients with negative blood cultures died more often with hypotension (p less than .02).
Conclusions: Septic shock is a major cause of death in intensive care patients. Refractory hypotension is a main cause of early deaths. Later on, multiple organ failure becomes the primary clinical problem and cause of mortality.