Research

Low systemic vascular resistance: differential diagnosis and outcome

Jairo Melo¹ and Jay I Peters²

¹  Department of Medicine, Division of Pulmonary Diseases/Critical Care Medicine, The University of Texas Health Science Center at San Antonio, Texas, USA

²  The South Texas Veterans Health Care System, Audie L. Murphy Memorial Veterans Hospital Division, San Antonio, Texas, USA

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Critical Care 1999, 3:71-77doi:10.1186/cc343

Published:	9 June 1999

Abstract

Objective

To determine the frequency and prognosis of the various causes of low systemic vascular resistance (SVR).

Design

Analysis of consecutive patients over a 5-year period; retrospective review.

Setting

Medical intensive care unit of a large university hospital.

Patients

Fifty-five patients with unexplained hypotension and a SVR less than 800 dynes × s/cm⁵.

Background

There are minimal data in the medical literature determining the frequency or outcome of patients with a low SVR that is unrelated to sepsis or the sepsis syndrome. We retrospectively reviewed and analyzed all hemodynamic data in a large university hospital over a 5-year period to determine the frequency and prognosis of the various causes of low SVR. Fifty-five patients with unexplained hypotension and a SVR less than 800dynes×s/cm⁵were identified.

Main results

Twenty-two patients (Groups 1 and 2) met the criteria for sepsis syndrome. The mean SVR for this group was 445 ± 168 dynes×s/cm⁵ with an associated mortality of 50%. Group 3 contained 20 patients with possible sepsis. Thirteen patients (Group 4) were nonseptic. The mean SVR of this group was 435 ± 180 dynes × s/cm⁵ with an associated mortality of 46%. Extremely low SVR (below 450 dynes × s/cm⁵) was associated with a significantly higher mortality regardless of the etiology.

Conclusions

At least a quarter of patients with hypotension and a low SVR have nonseptic etiologies. The patients with nonseptic etiologies have a similar mortality to septic patients. Clinicians should be aware of the wide spectrum of conditions that induce a low SVR.