Changes in lung function and pulmonary capillary permeability after cardiopulmonary bypass.
OBJECTIVE
To assess the possibility that changes in lung function following cardiopulmonary bypass are associated with increased pulmonary capillary permeability.


METHODS
A prospective, descriptive study.


METHODS
Adult cardiothoracic ICU in a post-graduate teaching hospital.


METHODS
Ten sequential patients undergoing cardiac surgery requiring cardiopulmonary bypass.


METHODS
Arterial blood gas tensions, helium dilution end-expiratory lung volume, and carbon monoxide transfer were measured by a rebreathing technique preoperatively and 2 hrs postoperatively. Lung extravascular protein accumulation index was measured by a double-isotope technique 2 hrs postoperatively and in a group of normal controls.


RESULTS
Mean +/- SEM alveolar-arterial PO2 gradient increased from 77 +/- 14 torr (10.3 +/- 1.8 kPa) to 138 +/- 24 torr (18.5 +/- 3.2 kPa) (p less than .01). Functional residual capacity decreased by 20.2 +/- 5.6% (p less than .01). Carbon monoxide transfer decreased by 26.7 +/- 5.3% (p less than .01) for the lung as a whole and by 17.9 +/- 3.2% (p less than .01) per liter of accessible gas volume. Protein accumulation index ranged from 0.03 to 3.2 x 10(-3) (median 0.6) postoperatively (median for normal subjects 0.4; p less than .05), although only one patient had a value indicative of clinically important endothelial injury.


CONCLUSIONS
Cardiac surgery involving cardiopulmonary bypass results in a deterioration in lung function characterized by a loss of lung volume, a reduction in carbon monoxide transfer, and an increase in the alveolar-arterial PO2 gradient. These changes do not appear to be mediated by an increase in pulmonary endothelial permeability.
Macnaughton
P D
PD
Department of Clinical Physiology, Anaesthesia, and Intensive Care, Royal Brompton National Heart and Lung Hospital, London, UK.
Braude
S
S
Hunter
D N
DN
Denison
D M
DM
Evans
T W
TW
D000368:Aged; D002199:Capillary Permeability / Q000502:physiology*; D002315:Cardiopulmonary Bypass / Q000295:instrumentation / Q000379:methods; D004727:Endothelium / Q000503:physiopathology; D005260:Female; D006801:Humans; D007204:Indium; D007205:Indium Radioisotopes; D016018:Least-Squares Analysis; D008168:Lung / Q000000981:diagnostic imaging / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D011184:Postoperative Period; D011877:Radionuclide Imaging; D012129:Respiratory Function Tests / Q000379:methods / Q000706:statistics & numerical data; D013667:Technetium; D014001:Tin; D017971:Tin Compounds
D007205:Indium Radioisotopes; D017971:Tin Compounds; D007204:Indium; C023599:stannous chloride; C020758:indium trichloride; D013667:Technetium; D014001:Tin