Predictive value of Downes score on respiratory failure in term neonates

Objective To explore the clinical significance of Downes score in predicting respiratory failure (RF) in term neonates. Methods From June 1, 2011 to December 31, 2013, 243 hospitalized term neonates with dyspnea, who were born at 37 to 42 gestational age and admitted to the hospital within 24 h after birth, were selected from Neonatal Medical Center of Huai'an Maternity and Child Healthcare. Downes scores were evaluated based on five indicators including respiratory rate, skin color, three depressions sign, moaning and lung breath sounds at the time of admission. RF was diagnosed based on clinical menifestations and radial arterial blood gas analysis. Receiver operating characteristic (ROC) curve analysis was performed to evaluate the predictive value of Downes score on RF. Results The average Downes score of the 243 cases was 6.57±0.86 and the RF rate was 69.6% (169/243). The RF rate was 93.4% (169/181) when Downes score ≥4.5, with the sensitivity, specificity, misdiagnostic rate and missed diagnositic rate of 100.0%, 83.8%, 16.2% and 0.0%, respectively. While, the RF rate was 80.7% (130/161) when Downes score ≥5.5, with the sensitivity, specificity, misdiagnostic rate and missed diagnositic rate of 76.9%, 58.1%, 41.9% and 23.1%, respectively. When Downes score ≥6.5, the incidence of RF was 97.6% (123/126), with the sensitivity, specificity, misdiagnositic rate and missed diagnositic rate of 72.8%, 95.9%, 4.1% and 27.2%, respectively. The cutoff value was 6.5 according to the Youden Index, which with lower rate of misdiagnosis and missed diagnosis. When Downes score ≥7.5, the incidence of RF was 100.0%(22/22), with the sensitivity, specificity, misdiagnositic rate and missed diagnosis rate of 13.1%, 100.0%, 0.0% and 87.0%, respectively. The area under the ROC curve was 0.906 (95%CI: 0.866-0.955). The higher the Downes score, the greater the possibility of RF (P=0.000). Conclusions Dynamic Downes scores in term neonates with dyspnea could predict the risk of RF. The higher the Downes score, the greater the possibility of RF. Key words: Respiratory insufficiency; Dyspnea; Infant, newborn; Severity of illness index