Fever and hypotension vs. frank septic shock: Elderly patients taking vasodilators who present with fever and hypotension have a higher incidence of negative blood cultures. A retrospective analysis of 3,726 patients.

BACKGROUND

Septic shock is a leading cause of mortality. Yet, blood cultures are negative in many cases, questioning the diagnosis. In the quest for characterization of "culture negative septic shock", the impact of chronic vasodilating medications was questioned.

METHODS

This was a retrospective analysis of patients with vital signs compatible with septic shock (fever > 37.9 or < 36 °C and systolic blood pressure < 90 mmHg).

RESULTS

The study included 3,726 patients (ages 65 to 90). Of these, 1,382 (37.1%) took chronic vasodilators. This group of patients had a lower rate of positive blood cultures compared to the group that did not receive vasodilators (28.5% vs. 32%; P = 0.026). They were older (median 80 vs. 78 years; P = 0.001), and their background included more cardiovascular diseases (P < 0.001). Their total length of hospital stay was shorter (median 4 vs. 6 days; P < 0.001) yet, they had a higher risk of in-hospital mortality (39% vs. 35.1%; P = 0.019). Taking chronic vasodilators was associated with decreased risk for bacteremia by 16% (P = 0.023). Older age, positive bacterial culture, and chronic vasodilation treatment were independently associated with increased risk for in-hospital mortality by 3% (HR = 1.03, 95% CI 1.02 - 1.04; P < 0.001), 36% (HR = 1.36, 95% CI 1.18 - 1.57; P < 0.001), and 21% (HR = 1.21, 95% CI 1.05 - 1.4; P = 0.009) respectively.

CONCLUSIONS

Chronic use of vasodilators amongst elderly patients presenting with fever and hypotension is associated with a higher incidence of negative blood cultures. We suggest these patients exhibit a combination of sepsis and shock rather than frank septic shock.