Faculty Collaboration Database

Mean airway pressure and response to inhaled nitric oxide in neonatal and pediatric patients. Lung 2005;183(6):441-53

Date

02/09/2006

Pubmed ID

16465603

DOI

10.1007/s00408-005-2555-2

Scopus ID

2-s2.0-32244435691 (requires institutional sign-in at Scopus site)   9 Citations

Abstract

Inhaled nitric oxide (iNO) can improve oxygenation and ventilation-perfusion (V/Q) matching by reduction of shunt (Qs/Qt) in patients with hypoxemic lung disease. Because the improvement in V/Q matching must occur by redistribution of pulmonary blood flow, and because high airway pressure (Paw) increases physiologic dead space (Vd/Vt), we hypothesized that high Paw may limit the improvement in V/Q matching during iNO treatment. iNO 0-50 ppm was administered during mechanical ventilation. Mechanical ventilator settings were at the discretion of the attending physician. Qs/Qt and Vd/Vt were derived from a tripartite lung model with correction for shunt-induced dead space. Data from 62 patients during 153 trials were analyzed for effects of Paw and iNO on Qs/Qt and Vd/Vt. Baseline Qs/Qt was slightly increased at Paw 16-23 cmH2O (p < 0.05), while Vd/Vt increased progressively with higher Paw (p < 0.002). Therapy with iNO significantly reduced Qs/Qt (p < 0.001) at all levels of mean Paw, reaching a maximum reduction at 16-23 cmH2O (p < 0.05), such that Qs/Qt during iNO treatment was similar at all levels of Paw. During iNO treatment, a reduction in Vd/Vt occurred only at Paw of 8-15 cmH2O (p < 0.05), and the positive relationship between Vd/Vt and Paw was maintained. These differential effects on Qs/Qt and Vd/Vt suggest that both high and low Paw may limit improvement in gas exchange with iNO. Analysis of gas exchange using this corrected tripartite lung model may help optimize ventilatory strategies during iNO therapy.

Author List

Hoffman GM, Nelin LD

Author

George M. Hoffman MD Chief, Professor in the Anesthesiology department at Medical College of Wisconsin

MESH terms used to index this publication - Major topics in bold

Bronchodilator Agents
Child
Humans
Infant, Newborn
Nitric Oxide
Persistent Fetal Circulation Syndrome
Pulmonary Alveoli
Pulmonary Gas Exchange
Respiratory Dead Space
Respiratory Distress Syndrome, Newborn
Ventilation-Perfusion Ratio