Peripheral Perfusion Index in Ugandan Children with Plasmodium falciparum Severe Malaria: Secondary Analysis of Outcomes in a 2014-2017 Cohort Study

OBJECTIVES: Continuous, noninvasive tools to monitor peripheral perfusion, such as perfusion index (PI), can detect hemodynamic abnormalities and assist in the management of critically ill children hospitalized with severe malaria. In this study of hospitalized children with severe malaria, we aimed to assess whether PI correlates with clinical markers of perfusion and to determine whether combining PI with these clinical measures improves identification of children with greater odds of mortality. DESIGN: Post hoc analysis of a prospective, multicenter, cohort study conducted between 2014 and 2017. SETTING: Two referral hospitals in Central and Eastern Uganda. PATIENTS: Six hundred children younger than 5 years old with severe malaria and 120 asymptomatic community children. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: PI was measured at 6-hour intervals for the first 24 hours of hospitalization. We compared PI to standard clinical perfusion measures such as capillary refill time, presence of cold peripheral limbs, or temperature gradient. Admission PI was highly correlated with clinical measures of perfusion. Admission PI was lower in children with severe malaria compared with asymptomatic community children; and, among the children with severe malaria, PI was lower in those with clinical features of poor perfusion or complications of severe malaria, such as shock and hyperlactatemia (all p < 0.02). Among children with severe malaria, lower admission PI was associated with greater odds of mortality after adjustment for age, sex, and severe malaria criteria (adjusted odds ratio, 2.4 for each log decrease in PI [95% CI, 1.0-5.9]; p = 0.045). Diagnostically, the presence of two consecutive low PI measures (< 1%) predicted mortality, with a sensitivity of 50% and a specificity of 76%. CONCLUSIONS: In severe malaria, PI correlates with clinical complications (including shock and elevated serum lactate) and may be useful as an objective, continuous explanatory variable associated with greater odds of later in-hospital mortality.