Improvement in oxygenation by prone position and nitric oxide in patients with acute respiratory distress syndrome.
OBJECTIVE
Inhaled nitric oxide (NO) and prone position improve arterial oxygenation in patients with the acute respiratory distress syndrome. This study was undertaken to assess the combined effects of NO and prone position in these patients.


METHODS
Prospective clinical study.


METHODS
General intensive care service in a community teaching hospital.


METHODS
14 mechanically ventilated adult patients with the acute respiratory distress syndrome (mean lung injury score 3.23+/-0.27).


RESULTS
We measured hemodynamic and oxygenation parameters in the supine position and 2 h later in the prone position, before and during inhalation of 10 ppm NO. A positive response in oxygenation was defined as a > or =20% increment in the arterial oxygen tension/fractional inspired oxygen ratio (PaO2/FIO2). In the prone position PaO2/FIO2 increased significantly (from 110+/-55 to 161+/-89 mm Hg, p<0.01) and venous admixture decreased (from 38+/-12 to 30+/-7%, p<0.01) compared to the supine position. Ten of the 14 patients were responders in the prone position. In the supine position, inhalation of NO improved oxygenation to a lesser extent, increasing PaO2/FIO2 to 134+/-64 mm Hg (p<0.01) and decreasing venous admixture to 35+/-12%, (p<0.01). Five of the 14 patients responded to NO inhalation supine and 8 of 14 responded prone (p = 0.22). The combination of NO therapy and prone positioning was additive in increasing PaO2/FIO2 (197+/-92 mm Hg) and decreasing venous admixture (27+/-8%) (p<0.01). This combination also showed a positive oxygenation response on compared to the supine value without NO in 13 of the 14 patients (93 %). NO-induced changes in PaO2/FIO2 were correlated to changes in pulmonary vascular resistance only in the prone position.


CONCLUSIONS
In patients with the acute respiratory distress syndrome, the combination of NO and prone position is a valuable adjunct to mechanical ventilation.
Intensive Care Service, Hospital de Sabadell, Universitat Autonoma de Barcelona, Parc Tauli s/n, E-08208 Sabadell, [corrected] Spain.
M
M
Martinez
E
E
Diaz
D
D
Joseph
A
A
Villagrá
A
A
Mas
R
R
Fernandez
L
L
Blanch
D000280:Administration, Inhalation; D000328:Adult; D000368:Aged; D001993:Bronchodilator Agents / Q000627:therapeutic use*; D005260:Female; D006439:Hemodynamics; D006801:Humans; D008297:Male; D008875:Middle Aged; D009569:Nitric Oxide / Q000627:therapeutic use*; D010100:Oxygen / Q000097:blood; D011175:Positive-Pressure Respiration; D016684:Prone Position; D011446:Prospective Studies; D012123:Pulmonary Ventilation; D012128:Respiratory Distress Syndrome / Q000503:physiopathology / Q000628:therapy*; D016896:Treatment Outcome
D001993:Bronchodilator Agents; D009569:Nitric Oxide; D010100:Oxygen