The Initial Response to Inhaled Nitric Oxide Treatment for Intensive Care Unit Patients with Acute Respiratory Distress Syndrome

Hsu, Chien-Wei
Lee, David Lin
Lin, Shoa-Lin
Sun, Shu-Fen
Chang, Hsueh-Wen

^aIntensive Care Unit, Internal Medicine Department,
^bRehabilitation Department, Veterans General Hospital Kaohsiung, and
^cDepartment of Biological Sciences, National Sun Yat-Sen University, Kaoshiung, Taiwan, ROC

Received: July 11, 2006

Accepted after revision: January 15, 2007

Published online: March 29, 2007

Chien-Wei Hsu, MD

Intensive Care Unit, Kaohsiung Veterans General Hospital

386, Ta-Chung 1st Road

Kaohsiung City, Taiwan (ROC)

Tel. +886 7342 0243 7050, Fax +886 7350 5220, E-Mail [email protected]

Respiration 75(3):p 288-295, March 2008. | DOI: 10.1159/000101478

Abstract

Background:

Inhaled nitric oxide (INO) can improve hypoxemia and reduce pulmonary hypertension, but there is a wide range of response to INO.

Objectives:

The aim of this study was to evaluate the effect of different INO concentrations in acute respiratory distress syndrome (ARDS) patients.

Methods:

Thirty-two adult ARDS patients who were supported by mechanical ventilator were included. INO was given at a concentration of 1, 5, 10, 20 and 40 ppm, sequentially. Arterial blood gas and mean pulmonary artery pressure (MPAP) were measured 30 min after INO concentrations changed.

Results:

There was a significant increase in PaO₂/FiO₂ (p < 0.0001) and a decrease in pulmonary vascular resistance index and MPAP (p < 0.0001) after INO use. INO concentrations required for improving oxygenation were in the range of 1–20 ppm, whereas concentrations required for decreasing MPAP were in the range of 1–40 ppm. PaO₂/FiO₂ worsened when the INO dose was adjusted above 20 ppm. Sixty-nine percent of ARDS patients were responders; 31% of them were nonresponders. Among responders, 64% of patients responded at 1 ppm, 36% at 5 ppm.

Conclusions:

The optimal doses for improving oxygenation and reducing PAP differ. The maximum PaO₂/FiO₂ was observed at a lower INO concentration than that required for the minimal MPAP. There was no further improvement in PaO₂/FiO₂ when the INO dose was adjusted above 20 ppm. Higher doses of INO treatment worsened oxygenation.