[Pressure-controlled mechanical ventilation: a simplified titration method of the extrinsic positive expiratory pressure].
OBJECTIVE
Extrinsic positive end-expiratory pressure (PEEPe) may improve gas distribution within the lungs, induce alveolar recruitment or, conversely, produce pulmonary overdistension, and modify the respiratory impedance. Under pressure-controlled mechanical ventilation (PCV) this phenomenon modifies the minute ventilation and the dynamic compliance of the respiratory system (Crs,dyn). This study was aimed to assess the incidence of a significant gain in Crs,dyn under the effect of PEEPe during PCV.


METHODS
Prospective, open, descriptive, case series study.


METHODS
Surgical intensive care unit patients, under sedation, neuromuscular blockade and PCV because of severe hypoxaemia (ARDS or acute lung injury).


METHODS
Four incremental levels of PEEPe (4 to 16 cmH2O) of 30 minute duration were applied. Crs,dyn, and PaO2/FIO2 were recorded at the end of each level of PEEPe. The resulting gain in Crs,dyn was calculated and considered as significant if it was greater than the upper limit of confidence (at 99.8%) of the statistical distribution of all the recorded gains.


RESULTS
Thirty patients were included, median and extreme values (within brackets) of PaO2/FIO2 of 117 [53-230] and Crs,dyn without PEEPe of 29 [14.3-46.8] mL.cmH2O-1. Among the 120 recorded gains, a gain in Crs,dyn was found significant at least once in 15 tests of PEEPe out of 30. Within the two groups of patients, the increase in PaO2/FIO2 with incremental PEEPe was similar. The levels of PEEPe producing the greatest increase in Crs,dyn were not correlated with the increase in PaO2/FIO2.


CONCLUSIONS
In 50% of the studied patients a significant gain in Crs,dyn was found, allowing a less traumatic PCV. These results suggest the clinical usefulness of this method of titration of PEEPe, which requires neither specific devices nor a disconnection of the patient.
Cohendy
R
R
Département d'anesthésie-réanimation, CHU de Nîmes, France.
Lefrant
J Y
JY
Mangin
R
R
Eledjam
J J
JJ
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000771:Anesthesia, Intravenous; D016001:Confidence Intervals; D003422:Critical Care; D006801:Humans; D000860:Hypoxia / Q000628:therapy; D008168:Lung / Q000378:metabolism; D008170:Lung Compliance; D008875:Middle Aged; D019148:Neuromuscular Blockade; D010100:Oxygen / Q000008:administration & dosage / Q000097:blood; D010101:Oxygen Consumption / Q000502:physiology; D011175:Positive-Pressure Respiration / Q000379:methods*; D011446:Prospective Studies; D011650:Pulmonary Alveoli / Q000378:metabolism; D012128:Respiratory Distress Syndrome / Q000628:therapy
D010100:Oxygen
Ventilation mécanique en pression contrôlée: une méthode simplifiée de titration de la pression expiratoire positive extrinsèque.