The effect of adenosine triphosphate on the functional status of the ductus arteriosus.
We investigated whether a low-dose infusion of ATP-MgCl2 could affect the functional status of the ductus arteriosus during hypoxia-induced pulmonary vasoconstriction. Three-day-old piglets were made hypoxic by ventilation with a mixture containing 10% oxygen, 4% CO2, and balance nitrogen. Serial infusions of ATP-MgCl2 at 0.1, 0.5, and 1.0 mg/kg/min were compared with preinfusion hypoxia baselines. The functional status of the ductus arteriosus was determined by change in transit time of a bolus of iced saline between thermistor probes in the pulmonary artery and aorta. The method was validated using a Blalock-Taussing shunt (subclavian to pulmonary artery) in 3-week-old piglets instrumented in a similar manner. In these three-day-old piglets, hypoxia alone produced a significant elevation in pulmonary artery pressure and reduction in PO2. All dose rates of ATP-MgCl2 produced a significant decrease in mean pulmonary artery pressure. Systemic pressure was significantly decreased only during the 1.0-mg/kg/min infusion. Transit times of a bolus of iced saline during the validation were definitive for characterizing a situation of "shunt open" or "shunt closed." Infusion of ATP-MgCl2 produced no change in the status of the ductus arteriosus in 45 (94%) of the determinations. In only three cases was the effect of ATP-MgCl2 sufficient to result in a functional change in the status of the ductus arteriosus. Pre- and postductal pulmonary artery PO2 were not altered during ATP-MgCl2 infusion, thus corroborating the transit time determinations. From these results, we conclude that an infusion of ATP-MgCl2 does not alter the functional status of the ductus arteriosus.
Paidas
C N
CN
Division of Pediatric Surgery, Johns Hopkin University School of Medicine, Baltimore, MD.
Dudgeon
D L
DL
Haller
J A
JA
Clemens
M G
MG
D000255:Adenosine Triphosphate / Q000494:pharmacology*; D000818:Animals; D000831:Animals, Newborn / Q000502:physiology; D004373:Ductus Arteriosus / Q000503:physiopathology*; D006976:Hypertension, Pulmonary / Q000503:physiopathology*; D000860:Hypoxia / Q000503:physiopathology; D008274:Magnesium / Q000494:pharmacology*; D015636:Magnesium Chloride; D008954:Models, Biological; D011651:Pulmonary Artery / Q000503:physiopathology; D013552:Swine
D015636:Magnesium Chloride; D000255:Adenosine Triphosphate; D008274:Magnesium