Use of a clinical protocol to assess the respective indications of prone position and nitric oxide in patients with ARDS
© Current Science Ltd 1998
Published: 1 March 1998
Inhalation of nitric oxide (NO) and prone position ventilation (PPV) have been showed to improve the PaO2/FiO2 ratio in patients with acute respiratory distress syndrome (ARDS). The aim of this study was to identify which of the following treatments (PPV, NO or PPV + NO) improved the PaO2/FiO2 ratio most in a patient. Ten consecutive patients presenting with severe acute respiratory failure (PaO2/FiO2 <150 mmHg) unrelated to congestive heart failure were studied.
The time course of the treatment was as follow: supine position (SPV) (H0 control value), PPV (H0 to H2), SPV (H2 to H3), PPV + NO (H3 to H5) and SPV + NO (H5 to H6). Oxymetric parameters were measured at the end of each cycle of treatment. During the protocol, ventilator settings were unchanged. A patient was considered as responder to a treatment when the PaO2/FiO2 ratio increased by a value of 20 mmHg compared to the control value. After the protocol time course, each patient received the treatment according to the best oxymetric results.
Two patients were no responders to PPV and 8 patients responded to PPV with an increase of PaO2/FiO2 of 122.8 ± 104.5 mmHg (mean ± sd). Five patients were responders to NO with an increase of PaO2/FiO2 of 51.8 ± 20.2 mmHg. Only one patient was not responsive to NO and to PPV, but responded to PPV + NO combination (+ 65 mmHg).
According to the results, the treatments selected were: 1) PPV + NO in 6 patients: increase of PaO2/FiO2 by a mean of 149.7 ± 89.6 mmHg; 2) PPV in 3 patients: increase of PaO2/FiO2 by a mean of 131.3 ± 124 mmHg; 3) NO alone in one patient: increase of PaO2/FiO2 by 75 mmHg.
Although the aim of the study was not to compare the 2 methods, it seems nevertheless that PPV was more effective than NO. An additive effect of PPV and NO was found in 6 out of 10 patients and especially in one patient not responding to PPV or NO alone.