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Effects of hydralazine on cardiac performance in infants receiving extracorporeal membrane oxygenation
G R Martin1, L Chauvin, B L Short
1Department of Pediatrics, Children's National Medical Center, Washington, D.C.
Insights
Hydralazine did not improve cardiac performance in infants on extracorporeal membrane oxygenation (ECMO). This study found no significant changes in cardiac output or contractility after administering hydralazine during partial cardiopulmonary bypass.
Area of Science:
- Cardiology
- Pediatric Critical Care
Background:
- Infants undergoing extracorporeal membrane oxygenation (ECMO) often experience impaired cardiac function.
- Afterload reduction is a potential strategy to improve cardiac performance in these critically ill neonates.
Purpose of the Study:
- To investigate the effects of hydralazine, an afterload-reducing agent, on cardiac performance in infants during partial cardiopulmonary bypass.
- To assess the impact of hydralazine on cerebral blood flow in infants supported by ECMO.
Main Methods:
- A prospective study involving infants receiving ECMO, divided into normotensive and hypertensive groups.
- Administration of hydralazine 1 hour after ECMO initiation.
- Measurement of load-dependent and load-independent cardiac performance indexes, including shortening fraction, cardiac output, and velocity of circumferential fiber shortening.
- Assessment of cerebral blood flow resistance index.
Main Results:
- Shortening fraction, cardiac output, and velocity of circumferential fiber shortening decreased during ECMO in both groups.
- Hydralazine administration did not result in significant changes in these cardiac performance parameters.
- The cerebral blood flow resistance index decreased during ECMO but remained unchanged after hydralazine administration.
- No significant differences were observed between normotensive and hypertensive groups regarding the effects of hydralazine.
Conclusions:
- Hydralazine does not appear to improve cardiac performance in infants during partial cardiopulmonary bypass with ECMO.
- Further research may be needed to explore alternative or adjunctive therapies for cardiac support in this population.
Abstract:
To determine the effects of afterload reduction on cardiac performance during partial cardiopulmonary bypass, we administered hydralazine to infants who were either normotensive (n = 11) or hypertensive (n = 12) 1 hour after extracorporeal membrane oxygenation (ECMO) was begun. Load-dependent and load-independent measures of cardiac performance and indexes of cerebral blood flow were measured. Infants in both groups had similar weight, heart rate, blood pressure, and inotropic support before ECMO. Shortening fraction was normal in both groups before ECMO (47 +/- 11% vs 49 +/- 10%; p greater than or equal to 0.05), decreased during ECMO (31 +/- 18% vs 39 +/- 12%; p greater than or equal to 0.05), and did not change after administration of hydralazine (31 +/- 12% vs 37 +/- 8%; p greater than or equal to 0.05). Cardiac output was normal in both groups before ECMO (176 +/- 71 vs 157 +/- 72 ml/kg per minute; p greater than or equal to 0.05), decreased during ECMO (120 +/- 80 vs 105 +/- 64 ml/kg per minute; p greater than or equal to 0.05), and did not change after hydralazine administration. Velocity of circumferential fiber shortening, an index of contractility (circumference per second), was normal in both groups before ECMO (1.96 +/- 0.57 vs 1.90 +/- 0.43 circ/sec; p greater than or equal to 0.05), decreased during ECMO (1.18 +/- 0.83 vs 1.56 +/- 0.58 circ/sec; p greater than or equal to 0.05), and did not change after hydralazine administration. The relationship between velocity of circumferential fiber shortening and wall stress was similar in both groups before ECMO, during ECMO, and after hydralazine administration. The cerebral blood flow resistance index was similar in both groups before ECMO (0.70 +/- 0.16 vs 0.70 +/- 0.20; p greater than or equal to 0.05), decreased during ECMO (0.45 +/- 0.13 vs 0.43 +/- 0.09; p greater than or equal to 0.05), and did not change after administration of hydralazine. We conclude that hydralazine does not improve cardiac performance during ECMO.