Objectives: Tachycardia is common in septic shock, but many patients with septic shock are relatively bradycardic. The prevalence, determinants, and implications of relative bradycardia (heart rate, < 80 beats/min) in septic shock are unknown. To determine mortality associated with patients who are relatively bradycardic while in septic shock.
Design: Retrospective study of patients admitted for septic shock to study ICUs during 2005–2013.
Setting: One large academic referral hospital and two community hospitals.
Patients: Adult patients with septic shock requiring vasopressors.
Measurements: Primary outcome was 28-day mortality. We used multivariate logistic regression to evaluate the association between relative bradycardia and mortality, controlling for confounding with inverse probability treatment weighting using a propensity score.
Results: We identified 1,554 patients with septic shock, of whom 686 (44%) met criteria for relative bradycardia at some time. Twenty-eight-day mortality in this group was 21% compared to 34% in the never-bradycardic group (p < 0.001). Relatively bradycardic patients were older (65 vs 60 yr; p < 0.001) and had slightly lower illness severity (Sequential Organ Failure Assessment, 10 vs 11; p = 0.004; and Acute Physiology and Chronic Health Evaluation II, 27 vs 28; p = 0.008). After inverse probability treatment weighting, covariates were balanced, and the association between relative bradycardia and survival persisted (p < 0.001).
Conclusions: Relative bradycardia in patients with septic shock is associated with lower mortality, even after adjustment for confounding. Our data support expanded investigation into whether inducing relative bradycardia will benefit patients with septic shock.
1Division of Pulmonary and Critical Care, Intermountain Medical Center, Murray, UT.
2Division of Pulmonary and Critical Care, University of Utah School of Medicine, Salt Lake City, UT.
3Department of Anesthesia, University of Chicago, Chicago, IL.
4Department of Anesthesia, Critical Care and Pain Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA.
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Supported, in part, by National Institute of General Medical Sciences (1K23GM094465 to Dr. Brown) and the Intermountain Research and Medical Foundation. The Intermountain Institutional Review Board approved this study with waiver of informed consent.
Dr. Talmor received support for article research from the National Institutes of Health. His institution received funding from the National Heart, Lung, and Blood Institute, the Gordon and Betty Moore Foundation, and Intensix. The remaining authors have disclosed that they do not have any potential conflicts of interest.
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