Gas exchange impairment and pulmonary densities after cardiac surgery.
In 11 patients with impaired respiratory function after coronary artery revascularization surgery, thoracic computed tomography (TCT) and cardiopulmonary profile were obtained. The patients were haemodynamically stable without clinical or radiological signs of lung oedema. Oxygenation was reduced in all patients (alveolo-arterial PO2-difference (PA-aO2) = 37.3 +/- 10.39 kPa, venous admixture (QVA/QT) = 26.4 +/- 4.4%) during mechanical ventilation with positive end-expiratory pressure (PEEP = 5 cmH2O) (0.5 kPa). TCT-scan analysis revealed considerable amounts of crest-shaped bilateral densities in dependent lung regions. There were no differences between the right and left hemithorax. Atelectatic lung tissues were defined as areas presenting with attenuation values of -200 to +20 Hounsfield Units. The magnitude of non-ventilated areas correlated with QVA/QT (r = 0.875, P < or = 0.01), but not with the duration of either extracorporeal circulation, surgical procedure or general anaesthesia. It is concluded that atelectasis in dependent lung areas contributes to impaired gas exchange after cardiac surgery.
Hachenberg
T
T
Department of Anaesthesiology, Westfälische Wilhelms-Universiät Münster, FRG.
Brüssel
T
T
Roos
N
N
Lenzen
H
H
Möllhoff
T
T
Gockel
B
B
Konertz
W
W
Wendt
M
M
D000368:Aged; D001794:Blood Pressure / Q000502:physiology; D001026:Coronary Artery Bypass; D005260:Female; D006801:Humans; D008168:Lung / Q000098:blood supply / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000097:blood; D010101:Oxygen Consumption / Q000502:physiology; D011175:Positive-Pressure Respiration; D011651:Pulmonary Artery / Q000502:physiology; D001261:Pulmonary Atelectasis / Q000000981:diagnostic imaging* / Q000503:physiopathology; D011659:Pulmonary Gas Exchange / Q000502:physiology*; D014057:Tomography, X-Ray Computed; D014655:Vascular Resistance / Q000502:physiology
D010100:Oxygen