Hemodynamic and gas exchange response to inhaled nitric oxide and prone positioning in acute respiratory distress syndrome patients.
OBJECTIVE
To analyze the single effect and the interaction of prone position and inhaled nitric oxide (iNO) on lung function and hemodynamic variables.


METHODS
2 x 2 factorial trial.


METHODS
Department of intensive care medicine at a university hospital.


METHODS
Fourteen patients on volume-controlled mechanical ventilation for acute respiratory distress syndrome (ARDS).


METHODS
Four experimental conditions, each one characterized by the patient's position (supine or prone) with iNO or without iNO.


RESULTS
Hemodynamic and gas exchange data were collected for each experimental condition. PaO2 was increased both by positioning (p < .01) and iNO (p < .01); iNO caused also a reduction in venous admixture (p < .01), pulmonary artery pressure (p < .01), and pulmonary vascular resistance index (p < .05). We could not demonstrate any significant interaction between the two treatments. The average effect of prone positioning was the same both with and without iNO, whereas the average effect of iNO was the same in both the prone and the supine position.


CONCLUSIONS
In the studied acute respiratory distress syndrome patients the average effects of iNO and positioning on oxygenation were additive and no interaction could be shown. A strategy including both treatments could warrant the best improvement in oxygenation, and should take into account the individual response to each treatment and the possible combination of the two.
Borelli
M
M
Institute of Anaesthesiology and Intensive Care, University of Milan, Department of Anaesthesia and Intensive Care, S Gerardo Hospital, Monza, Italy.
Lampati
L
L
Vascotto
E
E
Fumagalli
R
R
Pesenti
A
A
D000280:Administration, Inhalation; D000328:Adult; D005260:Female; D006801:Humans; D008297:Male; D009569:Nitric Oxide / Q000494:pharmacology*; D016684:Prone Position; D011659:Pulmonary Gas Exchange / Q000187:drug effects / Q000502:physiology*; D012128:Respiratory Distress Syndrome / Q000503:physiopathology*
D009569:Nitric Oxide