| |
Nitric Oxide Therapy Spares Sick Newborns From Risky Procedure
NEW YORK - February 17, 2000 - Critically ill babies unable to breathe properly due to dangerously high blood pressure in their lungs can avoid risky treatment on heart-lung machines by getting small, early doses of inhaled nitric oxide, according to a study published today in The New England Journal of Medicine.
John P. Kinsella, M.D., of the University of Colorado School of Medicine in Denver, one of the authors of today's report, received March of Dimes support from 1993 to 1996 to study the vital role of nitric oxide in the regulation of blood flow in the lungs of animals. This work provided important insight into lung diseases in human infants, such as persistent pulmonary hypertension (PPHN).
Dr. Kinsella also was one of the first physicians in the country to treat newborns with PPHN with inhaled nitric oxide, a chemical produced naturally in the body. He and others demonstrated that nitric oxide therapy could greatly improve the amount of oxygen in the blood of newborns with PPHN.
What Is PPHN?
At birth, in response to the first minutes of breathing air, the blood vessels in the lungs normally relax and allow blood to flow through them. This makes it possible for the blood to exchange carbon dioxide, a waste product, for oxygen. However, when this adaptation fails for some reason and pulmonary high blood pressure (hypertension) persists, newborns may die or suffer damage to the brain and other vital organs due to lack of oxygen in their blood.
When all other treatments fail, newborns with PPHN usually undergo extracorporeal membrane oxygenation (ECMO), a highly invasive and expensive surgical procedure involving a machine similar to the heart-lung bypass used in operating rooms. This desperate measure leads to neurologic abnormalities in up to 20 percent of the babies who survive.
The Food and Drug Administration approved nitric oxide treatment in December 1999 for babies with PPHN born at 34 weeks and older (37 weeks is considered full term).
PPHN affects some 5,000 to 7,000 infants a year. It may be a contributory factor in severe respiratory distress syndrome (RDS), and may help explain why a substantial percentage of babies with RDS who are treated with surfactant do not respond well. Surfactant helps the microscopic air sacs in the lungs inflate (ventilation), but does not help the vessels relax to permit blood flow (perfusion). A balance between ventilation and perfusion is necessary for proper breathing.
"Low-dose nitric oxide therapy for persistent pulmonary hypertension of the newborn," by Reese H. Clark, M.D., of Duke University and colleagues, including Dr. Kinsella, in the Clinical Inhaled Nitric Oxide Research Group, appears today in the New England Journal of Medicine, Volume 342, Number 7, February 17, 2000.
|
|
