Abstract
Background: The onset of response to inhaled nitric oxide (INO) vary in the literature. It is important to identify non responders from those who respond to the INO in order to formulate management plans.
Objective: To define a time limit for the acute effects of inhaled nitric oxide (INO) on systemic oxygenation beyond which the response to the inhaled therapy is unlikely to take place in sick newborn infants suffering from persistent pulmonary hypertension.
Methods: This study was a hospital-based retrospective chart review. All infants who received INO for the treatment of pulmonary hypertension with acute sever hypoxemic respiratory failure over a period of four years were analyzed using the oxygenation index (OI) as an indicator for starting the therapy and following the response for total period of gas exposure. The OI was measured before and every one to six hours after initiating the therapy. The starting time of the gas, timing of first response, course of responses, blood gases, calculated OI before, during, and after initiation of the gas were also recorded until INO was discontinued.
Results: Seventy-six infants were studied: 35 infants were born at 24 to 32 weeks gestation age, and 41 at 33 weeks gestation to full term. Mean duration time of exposure to INO was 53 hours in the preterm group and 84 hours in the near and full term group. The mean age at starting the therapy was 59 hours in the preterm group and 23 hours in the near and full term group. The degree of response to INO was as follows: 52.2% full response, 27.5% partial response, and 20.3% no response. The first two (2) hours contained the highest number of responders, 64%; while the response was 15% in the second two hours. No responders were recorded after eight hours of exposure.
Conclusion: Exposure to INO for eight (8) hours could be carefully considered as a time limit to determine the type of response to such gas and to help in making a decision of ``wean to discontinue'' in non-responders.
Get full access to this article
View all access options for this article.