Tachypnea and other danger signs vs pulse oximetry for prediction of hypoxia in severe pneumonia/very severe disease

Abstract

Objectives

To compare the performance of respiratory rate and other clinical signs against pulse oximetry for predicting hypoxia in children with Severe pneumonia/Very severe disease as per Integrated Management of Neonatal and Childhood Illness (IMNCI) classification.

Design

Cross-sectional study.

Setting

Pediatric emergency department of a tertiary-care hospital in Delhi, India.

Subjects

112 hospitalized children (2 mo – 5 y) with Severe pneumonia/Very severe disease as per IMNCI classification.

Methods

Respiratory rate was recorded at enrolment, along with other clinical signs and symptoms. Oxygen saturation (SpO₂) was measured by a pulse oximeter. Clinical predictors of hypoxia (SpO₂ <90%) and their combinations (index test) were evaluated for their sensitivity, specificity, positive predictive value and negative predictive value for diagnosis of hypoxia, against pulse oximetry (reference test).

Results

Hypoxia was present in 57 (50.9%) children. Presence of tachypnea, head nodding, irritability, inability to drink/ breastfeed, vomiting, and altered sensorium was significantly associated with hypoxia (P<0.05). Multiple logistic regression revealed that age-specific tachypnea (RR≥70/min for 2–12 mo, and RR ≥60/min for ≥12 mo), head nodding, and inability to drink/breastfeed were independent predictors for hypoxia with sensitivity of 70.2%, 50.9% and 75.4%, respectively; and specificity of 88.9%, 96.4%, and 90.9%, respectively. When all three predictors were used in conjunction, the sensitivity increased to 91.2% and specificity was 81.8%.

Conclusions

No single clinical sign can perform as well as pulse oximetry for predicting hypoxia in children with severe pneumonia. In settings where pulse oximetry is not available, combination of signs, age-specific tachypnea, head nodding, and inability to drink/breastfeeding has acceptable sensitivity and specificity.