title: Short-term effect of inhaled nitric oxide and prone positioning on gas exchange in patients with severe acute respiratory distress syndrome.
abstract: OBJECTIVE
  To compare the short-term effects of inhaled nitric oxide (NO) and prone positioning in improving oxygenation in acute respiratory distress syndrome (ARDS).
  
  
  METHODS
  Charts of consecutive ARDS patients (lung injury score >2) during a 2-yr period, tested for both inhaled NO and prone positioning efficacy were retrospectively reviewed. Variations in the Pao2/Fio2 ratio induced by inhaled NO and prone positioning were evaluated.
  
  
  RESULTS
  Twenty-seven patients (age, 42+/-17 yrs) were included. Simplified Acute Physiology Score II was 45+/-14. Mortality rate in the intensive care unit was 63%. The causes of ARDS were pneumonia (n = 14), extra-lung infection (n = 5), and noninfectious systemic inflammatory response syndrome (n = 8). Lung injury score was 2.7+/-0.3. At baseline, before the initiation of inhaled NO, the Pao2/Fio2 ratio was 97+/-46 torr and before prone positioning, 92+/-26 torr. Variations in the Pao2/Fio2 ratio were lower at start of NO therapy (11+/-4 ppm) than that observed at prone positioning initiation (23+/-31 vs. 62+/-78 torr, p<.05). An increase in variations in the Pao2/Fio2 ratio of >15 torr was associated with prone positioning in 16 patients (59%) and with NO inhalation in 13 patients (48%) (not significant). An increase in variations in the Pao2/Fio2 ratio of >15 torr was associated with both techniques in only six patients (22%). There was no correlation between the response to prone positioning and the response to inhaled NO (r2 = .005; p = .73).
  
  
  CONCLUSIONS
  Prone positioning improves hypoxemia significantly better than does inhaled NO. The response to one technique is not predictive of the response to the other technique.
authors.affiliation: Department of Réanimation des Maladies Infectieuses, Hôpital Bichat-Claude Bernard, Paris, France.
authors.forename: H
authors.initials: H
authors.lastname: Dupont
authors.forename: H
authors.initials: H
authors.lastname: Mentec
authors.forename: C
authors.initials: C
authors.lastname: Cheval
authors.forename: P
authors.initials: P
authors.lastname: Moine
authors.forename: L
authors.initials: L
authors.lastname: Fierobe
authors.forename: J F
authors.initials: JF
authors.lastname: Timsit
mesh_terms: D018806:APACHE; D000280:Administration, Inhalation; D000293:Adolescent; D000328:Adult; D000368:Aged; D001784:Blood Gas Analysis; D001993:Bronchodilator Agents / Q000494:pharmacology / Q000627:therapeutic use*; D003131:Combined Modality Therapy; D005260:Female; D016166:Free Radical Scavengers / Q000494:pharmacology / Q000627:therapeutic use*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009569:Nitric Oxide / Q000494:pharmacology / Q000627:therapeutic use*; D010100:Oxygen / Q000097:blood; D011175:Positive-Pressure Respiration / Q000379:methods; D011237:Predictive Value of Tests; D016684:Prone Position; D011659:Pulmonary Gas Exchange / Q000187:drug effects*; D012128:Respiratory Distress Syndrome / Q000209:etiology / Q000378:metabolism* / Q000401:mortality / Q000503:physiopathology / Q000628:therapy*; D012189:Retrospective Studies; D012720:Severity of Illness Index; D013997:Time Factors
chemical_list: D001993:Bronchodilator Agents; D016166:Free Radical Scavengers; D009569:Nitric Oxide; D010100:Oxygen