Inhaled nitric oxide: clinical applications, indications, and toxicology.
OBJECTIVE
Although the analogy of nitric oxide (NO) to Endothelium-derived Relaxing Factor remains controversial, medical use of exogenous NO gas by inhalation has grown exponentially. This review presents the mechanisms of action of inhaled NO in pulmonary hypertension, hypoxaemia, inflammation and oedema, as well as its therapeutic and diagnostic indications with emphasis on acute respiratory distress syndrome (ARDS) and toxicology.


METHODS
Two medical databases (Current Contents, Medline) were searched for citations containing the above-mentioned key words to December 1996. Moreover, many presentations in congresses such as 4th International Meeting of Biology of Nitric Oxide, 52nd and 53rd Annual Meeting of Canadian Anaesthetists' Society or 10th Annual Meeting of European Association of Cardiothoracic Anaesthesiologists were used.


RESULTS
Inhaled NO is now recognized as an invaluable tool in neonatal and paediatric critical care, and for heart/lung surgery. Other clinical applications in adults, such as chronic obstructive pulmonary disease and ARDS, require a cautious approach. The inhaled NO therapy is fairly inexpensive, but it would seem that it is not indicated for everybody with regards to the paradigm of its efficiency and potential toxicity. The recent discovery of its anti-inflammatory and extrapulmonary effects open new horizons for future applications.


CONCLUSIONS
Clinical use of inhaled NO was mostly reported in case series, properly designed clinical trials must now be performed to establish its real therapeutic role. These trials would permit adequate selection of the cardiopulmonary disorders, and subsequently the patients that would maximally benefit from inhaled NO therapy.
Troncy
E
E
Department of Anaesthesia, Centre Hospitalier de l'Université de Montréal-Pavillon Notre-Dame, Québec, Canada.
Francoeur
M
M
Blaise
G
G
D000280:Administration, Inhalation; D000328:Adult; D000893:Anti-Inflammatory Agents / Q000494:pharmacology; D002648:Child; D002986:Clinical Trials as Topic; D003422:Critical Care; D016527:Drug Costs; D005544:Forecasting; D006801:Humans; D006976:Hypertension, Pulmonary / Q000188:drug therapy; D000860:Hypoxia / Q000188:drug therapy; D007231:Infant, Newborn; D008168:Lung / Q000601:surgery; D008173:Lung Diseases, Obstructive / Q000188:drug therapy; D009569:Nitric Oxide / Q000008:administration & dosage / Q000009:adverse effects / Q000191:economics / Q000494:pharmacology / Q000627:therapeutic use*; D018579:Patient Selection; D011014:Pneumonia / Q000188:drug therapy; D011654:Pulmonary Edema / Q000188:drug therapy; D012107:Research Design; D012128:Respiratory Distress Syndrome / Q000188:drug therapy; D012127:Respiratory Distress Syndrome, Newborn / Q000188:drug therapy; D019141:Respiratory System Agents / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D012138:Respiratory Therapy / Q000191:economics; D013903:Thoracic Surgery
D000893:Anti-Inflammatory Agents; D019141:Respiratory System Agents; D009569:Nitric Oxide