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Abstract

Introduction: There are an estimated 390 million dengue virus infections worldwide, 96 million manifesting clinically, resulting in substantial morbidity and mortality in tropical and sub-tropical regions. Infected patients are at risk for dengue hemorrhagic fever and death from plasma leakage, decreased intravascular volume, and shock. Early recognition and proper intravascular volume resuscitation improve morbidity and mortality. The purpose of this study was to evaluate a noninvasive method which could potentially provide a real-time assessment of the risk for shock. Methods: Dengue patients admitted to Queen Sirikit National Institute for Child Health in Bangkok were enrolled in the study. Hematocrits (Hct) were determined at least once daily and the time of maximum Hct was noted. A blood sample was also taken 4–5 days after hospital discharge to assess baseline Hct and determine the maximum percent increase in Hct for each patient. An increase in Hct greater than 20% indicated plasma leakage and an enhanced risk for shock. A noninvasive SmO2 sensor was placed on the upper arm or thigh of the patient and SmO2 data were recorded intermittently during their 2–4 day hospital stay. SmO2 nearest the time of maximum Hct was extracted from the recorded data; only patients who had SmO2 values within 8 hours of the blood measurement were included. SmO2 at the time of maximum Hct was compared between patients with and without significant hemoconcentration using a t-test. Results: There were 11 patients with Hct increase >20% and 17 patients with Hct increase ≤20%. SmO2 was 53 ± 11% for patients with hemoconcentration and 62 ± 10% for those patients without; p=0.03. Conclusions: SmO2 was significantly lower for patients with substantial hemoconcentration in agreement with previous work that showed SmO2 to be a sensitive indicator of hypovolemia. Further work is required to determine if real-time assessment of SmO2 can help direct therapy to minimize the risk for shock in dengue patients.