Title : Role of perfusion index (PI) as a screening tool in early detection of dengue shock syndrome (severe dengue) at a tertiary care centre in Northwestern India – a prospective observational study
Abstract:
Research Question
Can Perfusion Index (PI), a non-invasive pulse oximetry-derived parameter, serve as an effective bedside screening tool for identifying severe dengue and dengue shock syndrome in children?
Aims and Objectives
To evaluate the utility of PI in early identification of severe dengue and dengue shock syndrome, assess its association with biochemical markers of tissue hypoperfusion, and determine its response to therapeutic interventions.
Materials and Methods
This prospective observational study was conducted over 18 months in the Pediatric Emergency Department of AIIMS Jodhpur. A total of 116 children with confirmed dengue were included. PI was measured using a Masimo pulse oximeter at presentation and monitored serially over 48 hours. Clinical severity was classified according to WHO 2009 criteria. Associations with shock, serum lactate, metabolic acidosis, laboratory abnormalities, PICU admission, and response to fluid resuscitation were evaluated using appropriate statistical tests, odds ratios (OR), and receiver operating characteristic (ROC) analysis.
Observations and Results
The median age was 12 years (IQR 10–15), with 72.4% males. Severe dengue accounted for 44.8% of cases, while 72.4% had clinically significant dengue (dengue with warning signs or severe dengue).
At a PI cutoff of <1.5, diagnostic performance was as follows:
- Clinically significant dengue: Sensitivity 78.6%, specificity 56.3%, positive predictive value (PPV) 82.5%, negative predictive value (NPV) 50%, and diagnostic accuracy 72.4%.
- Dengue shock syndrome: Sensitivity 81.3%, specificity 60.3%, PPV 59.1%, and NPV 82.0%, with an accuracy of 69.0%.
The strongest association was observed between low PI and shock (OR 6.58). Low PI was also associated with hyperlactatemia (OR 5.31), hemoconcentration (OR 3.73), elevated C-reactive protein (OR 3.25), metabolic acidosis (OR 2.76), hepatic involvement (OR 2.26), and PICU admission (OR 4.20).
Importantly, PI improved following fluid bolus administration in 36 of 38 children (94.7%), demonstrating its potential utility as a dynamic marker of therapeutic response.
Discussion
Low PI demonstrated clinically meaningful associations with circulatory compromise and established biochemical markers of hypoperfusion. Its bedside availability and responsiveness to fluid resuscitation support its potential role in early risk stratification and serial hemodynamic assessment.
Conclusion
Perfusion Index is a simple, non-invasive, readily available screening parameter for identifying children at risk of severe dengue and shock. Incorporating PI alongside conventional clinical assessment may facilitate earlier recognition of circulatory compromise and monitoring of treatment response, particularly in resource-limited settings.
