Inotropes are commonly used in hypotensive SN. Their effects on the pulmonary circulation is poorly understood in SN. 20 hypotensive newborns>1750 gm. were randomly assigned to start with either D or E and increased in stepwise fashion (D 5,10,15 and 20 Mcg/kg/min and E 0.125, 0.25, 0.375 and 0.5 Mcg/kg/min) every 20 min until the desired mean blood pressure (MBP) is achieved. If MBP is not achieved at the maximum dose the other medication is added. Data collected were, heart rate, MBP, and pulsed doppler of patent ductus arteriosus (PDA). To calculate the mean pulmonary pressure (MPP), the mean pressure gradient (MPG) across the PDA was subtracted from a simultaneous MBP. The MPG across the PDA was calculated by tracing the doppler signal over the entire cardiac cycle.12 SN had a PDA during the duration of the study shown in the table.

Table 1
Full size table

(B= baseline, HIR= highest infusion rate, E=End, * p<0.05 compared to B).

Both D & E caused significant increases in MBP and a concomitant increase in MPP.