The Effect of Minimally Invasive Surfactant Therapy on Diaphragmatic Activity.

de Waal, Cornelia G; Hutten, Gerard J; de Jongh, Frans H; van Kaam, Anton H

BACKGROUND Minimally invasive surfactant therapy (MIST) is increasingly used to treat preterm infants with respiratory distress syndrome (RDS). However, the effect of MIST on breathing effort is poorly studied. OBJECTIVES To describe the effect of MIST on neural breathing effort assessed with transcutaneous electromyography of the diaphragm (dEMG) in preterm infants with RDS. METHODS Preterm infants with a gestational age < 37 weeks treated with MIST for RDS were included. dEMG measurements were done from 15 min before to 1 h after MIST. The percentage change in dEMG activity after MIST and the clinical response were analyzed. RESULTS Twenty preterm infants (mean gestational age 29.3 [SD 2.1] weeks; mean birth weight 1,230 [SD 391] g) were included. Seventeen infants did complete the 1-h measurement. Eleven (65%) infants had a decrease in their peakdEMG activity (median change -11.8% [IQR -26.8 to 5.8, p = 0.08]) 1 h after MIST. TonicdEMG activity decreased in 12 (71%) infants, with a median reduction of 6.3% (IQR -29.2 to 9.0, p = 0.07). FiO2 showed a rapid decrease following MIST (before, 0.47 [IQR 0.38-0.84]; 1 h after, 0.25 [IQR 0.21-0.30], p < 0.001). CONCLUSION In addition to improved oxygenation, MIST results in a decrease in neural breathing effort measured by dEMG activity in the majority of preterm infants with RDS.