Lung Ultrasound as a Predictor of Mechanical Ventilation in Neonates Older than 32 Weeks

The prognosis of neonatal respiratory distress may be difficult to estimate at admission. Lung ultrasound is a useful diagnostic tool that is quick, requires little training, and is radiation free.

This study aims to analyze whether early lung ultrasound can predict respiratory failure.

From January to December 2014, lung ultrasound was performed on neonates admitted with breathing difficulties if they were older than 32 weeks and not intubated. A neonatologist, not aware of the patient's clinical condition, analyzed the stored ultrasound images. The findings were classified into the following 2 groups according to the potential risk of a bad respiratory outcome: low risk (normal or transient tachypnea of the newborn) or high risk (respiratory distress syndrome, meconium aspiration syndrome, pneumothorax, or pneumonia). A second investigator made the same classification after reading the chest X-rays. Respiratory failure was defined as a need for mechanical ventilation during the first day of life.

In total, 105 neonates were recruited (64.8% in the low-risk sonography group and 35.2% in the high-risk sonography group). Of those, 20% needed intubation, and this was more frequent in the high-risk group (relative risk = 17.5; 95% CI 4.3-70.9, p < 0.01). As predictors of respiratory failure, lung ultrasound and chest X-ray showed a high index of agreement (κ coefficient = 0.91; 95% CI 0.83-1, p < 0.01) and good accuracy (ultrasound: 95% sensitivity, 82.5% specificity, and a negative predictive value of 98.5%).

Early lung ultrasound is a useful tool to determine which neonates admitted with respiratory distress will require mechanical ventilation. It may help the clinician to carrying out appropriate transfers.