L. Blanch D. Joseph R. Ferna ´ndez A. Mas M. Martinez J. Valle ´s E. Diaz F. Baigorri A. Artigas Hemodynamic and gas exchange responses to inhalation of nitric oxide in patients with the acute respiratory distress syndrome and in hypoxemic patients with chronic obstructive pulmonary disease Intensive Care Med (1997) 23:51–57 © Springer-Verlag 1997 ORIGINAL Received: 19 December 1995 Accepted: 28 September 1996 Supported by grant 95/1390 from Fondo de Investigaciones Sanitarias (Ministerio de Sanidad y Consumo of Spain) L. Blanch ( ✉ ) · D. Joseph · R. Ferna ´ndez A. Mas · M. Martinez · J. Valle ´s · E. Diaz F. Baigorri · A. Artigas Intensive Care Service, Hospital de Sabadell, Parc Taulı ´ s/n, E-08208 Sabadell, Spain FAX: +34 (3) 723 3863 Abstract Objective: Inhalation of ni- tric oxide (NO) can improve oxygena- tion and decrease mean pulmonary artery pressure (MPAP) in patients with the acute respiratory distress syn- drome (ARDS). It is not known whether inhaled NO exerts a similar effect in hypoxemic patients with chronic obstructive pulmonary disease (COPD). Design: Prospective clinical study. Setting: General intensive care unit in Sabadell, Spain. Patients: Nine mechanically ventilated COPD patients (mean age 72 ± 2 years; forced expiratory volume in 1 s 0.91 ±0.11 l) and nine ARDS patients (mean age 57 ± 6 years; mean lung in- jury score 2.8 ± 0.1) Measurements and results: We mea- sured hemodynamic and gas exchange parameters before NO inhalation (basal 1), during inhalation of 10 ppm NO (NO-10), and 20 min after NO was discontinued (in basal 2) in the ARDS group. In the COPD group, these parameters were measured be- fore NO inhalation (basal 1), during different doses of inhaled NO (10, 20, and 30 ppm), and 20 min after NO was discontinued (basal 2). A positive response to NO was defined as a 20% increment in basal arterial partial pres- sure of oxygen (PaO 2 ). MPAP and pulmonary vascular resistance (PVR) decreased significantly, while other hemodynamic parameters remained unchanged after NO-10 in both groups. Basal oxygenation was higher in the COPD group (PaO 2 /FIO 2 (fractional inspired oxygen) 190 ± 18 mmHg) than in the ARDS group (PaO 2 /FIO 2 98 ± 12 mmHg), (p<0.01). After NO-10, PaO 2 /FIO 2 in- creased (to 141 ± 17 mmHg, p<0.01) and Qva/Qt decreased (39 ± 3 to 34 ± 3%, p<0.01) in the ARDS group. There were no changes in PaO 2 /FIO 2 and Qva/Qt when the NO concentra- tion was increased to 30 ppm in the COPD group. In both groups, a corre- lation was found between basal MPAP and basal PVR, and between the NO-induced decrease in MPAP and in PVR. The NO-induced in- crease in PaO 2 /FIO 2 was not corre- lated with basal PaO 2 /FIO 2 . In the ARDS group, six of the nine patients (66%) responded to NO and in the COPD group, two of nine (22%) (p=0.05). Conclusions: NO inhalation had simi- lar effects on hemodynamics but not on gas exchange in ARDS and COPD patients, and this response probably depends on the underlying disease. Key words Nitric oxide · Gas exchange · Mechanical ventilation · Chronic obstructive pulmonary disease · Acute respiratory distress syndrome