All issues > Volume 40(11); 1997

Original Article

J Korean Pediatr Soc. 1997;40(11):1508-1519. Published online November 15, 1997.

Influences of the Intrapulmonary R→L Shunt on PaO2 and PaCO2 after Instillation of Exogenous Pulmonary Surfactant to Premature Neonates with Respiratory Distress Syndrome

Yoon Hyung YH Park¹, Sei Woo SW Chung¹, Seung Baik SB Han¹, Young Se YS Kwon¹, Ji Youn JY Kim¹, Woo Sik WS Cheong¹, Dae Hyun DH Lim¹, Byong Kwan BK Son¹

¹Department of Pediatrics, InHa University Hospital, Seongnam, Korea

Abstract

Purpose
: We are inclined to analyze the relationship between the intrapulmonary right-to-left shunt and the PaO2/PaCO2 after endotracheal single-dose surfactant instillation to premature neonates with respiratory distress syndrome within 6 hours after birth.
Methods
: From Jan. 1993 to Jun. 1995, we have conducted a clinical trial of surfactant replacement therapy to the premature neonates with respiratory distress syndrome at the neonatal intensive care unit of InHa University Hospital. The surfactant group(n=17) was given Surfactant-TA and mechanical ventilator care, but the control group(n=22) was treated with only mechanical ventilator. We analyzed umbilical arterial blood gases and estimated respiratoy indexes before and after treatment.
Results
: 1) The QSP/QT decreased initially in the surfactant group, but significantly increased 24 hours after treatment in the control group(40.6¡¾4.7%, P < 0.05). 2) The PaO2 significantly decreased 2 hours and 24 hours after treatment in the control group(60.8¡¾10.1mmHg, 63.5¡¾7.6mmHg, P < 0.05 respectively). There were significant correlations between the QSP/QT and the PaO2 in both groups, and specifically in the conrol group 24 hours after treatment(r=-0.94, P < 0.001). 3) The PaCO2 significantly increased 1 hour after treatment, but significantly decreased specifically in the control group 24 hours after treatment(32.5¡¾1.8mmHg, P < 0.01). However, there were no signifacnt correlations between the QSP/QT and the PaCO2 in both groups.
Conclusions
: Specifically in the control group 24 hours after treatment, with hypocapnia, significant increase in pulmonary blood flow to capillary shunt and low VA/Q units (VA/Q< 0.1) at high FIO2(> 0.5) resulted in a decrease in PaO2 and also a significant relationship was found between the QSP/QT and the PaO2. However, there was no significant relationship between the QSP/QT and the PaCO2.

Keywords :Intrapulmonary right-to-left shunt(QSP/QT), PaO2, PaCO2, Exogenous surfactant, Respiratory distress syndrome, Hypocapnia