Prospective, randomized, controlled evaluation of the preventive effects of positive end-expiratory pressure on patient oxygenation during one-lung ventilation.
OBJECTIVE
This prospective, randomized, controlled study evaluated the effects on oxygenation by applying a selective and patient-specific value of positive end-expiratory pressure (PEEP) to the dependent lung during one-lung ventilation.


METHODS
Fifty patients undergoing thoracic surgery under combined epidural/general anaesthesia were randomly allocated to receive zero PEEP (Group ZEEP, n = 22), or the preventive application of PEEP, optimized on the best thoracopulmonary compliance (Group PEEP, n = 28). Patients' lungs were mechanically ventilated with the same setting during two- and one-lung ventilation (FiO2 = 0.5; VT = 9mL kg(-1), inspiratory :expiratory time = 1 : 1, inspiratory pause = 10%).


RESULTS
Lung-chest wall compliance decreased in both groups during one-lung ventilation, but patients of Group PEEP had 10% higher values than patients with no end-expiratory pressure (ZEEP) applied--Group ZEEP (P < 0.05). During closed chest one-lung ventilation, the PaO2 : FiO2 ratio was lower in Group PEEP (232 +/- 88) than in Group ZEEP (339 +/- 97) (P < 0.05); but no further differences were reported throughout the study. No differences were reported between the two groups in the need for 100% oxygen ventilation (10 patients of Group ZEEP (45%) and 14 patients of Group PEEP (50%) (P = 0.78)) or re-inflation of the operated lung during surgery (two patients of Group ZEEP (9%) and three patients of Group PEEP (10%) (P = 0.78)). Postanaesthesia care unit discharge required 48 min (25th-75th percentiles: 32-58 min) in Group PEEP and 45 min (30-57 min) in Group ZEEP (P = 0.60).


CONCLUSIONS
The selective application of PEEP to the dependent, non-operated lung increases the lung-chest wall compliance during one-lung ventilation, but does not improve patient oxygenation.
Mascotto
G
G
Vita-Salute University of Milan, IRCCS H. San Raffaele, Department of Anaesthesiology, Milan, Italy.
Bizzarri
M
M
Messina
M
M
Cerchierini
E
E
Torri
G
G
Carozzo
A
A
Casati
A
A
D000767:Anesthesia, Epidural; D000768:Anesthesia, General; D001784:Blood Gas Analysis; D005260:Female; D006801:Humans; D008170:Lung Compliance / Q000502:physiology; D008297:Male; D008875:Middle Aged; D008991:Monitoring, Physiologic; D010100:Oxygen / Q000097:blood*; D011175:Positive-Pressure Respiration; D011446:Prospective Studies; D012121:Respiration, Artificial; D019616:Thoracic Surgical Procedures
D010100:Oxygen