Clinical correlates in acute lung injury - Response to inhaled nitric oxide

Study objectives: The use of inhaled nitric oxide (NO) in the management of patients with ARDS has become widespread, although not all patients respond to this form of support. The aim of this study was to examine the relationship of responsiveness to inhaled NO and features of underlying disease. Design: Prospective observational study. Setting: The ICU of a university-affiliated, tertiary referral hospital. Patients: Twenty-six adult patients with established ARDS. Interventions: Conventional support for multiple organ failure, plus inhaled NO. Measurements and results: Response to inhaled NO was assessed, and ARDS was characterized in terms of pulmonary morphology (scoring of high-resolution CT); inflammation (BAL neutrophil count and plasma myeloperoxidase concentration); and markers of lung injury severity (oxygenation deficit and pulmonary vascular resistance [PVR]). Fourteen patients responded to NO and 12 did not. There were no differences between the two groups in terms of CT score, inflammatory status, baseline oxygenation deficit, lung injury score, or PVR. Additionally, there was no difference in survival between responders and nonresponders. Patients who developed ARDS after thoracic surgery were significantly more likely to die than other patients (relative risk 4.1, p < 0.01). The oxygenation deficit and lung injury score correlated better with the extent of ground-glass opacification than with the volume of consolidated lung tissue. Conclusion: We were unable to identify features of disease likely to be associated with a clinically useful response to inhaled NO therapy using the parameters studied.