Effects of pericardiectomy on canine pulmonary blood volume during hypervolaemia.
OBJECTIVE
The aim was to determine the effect of the pericardium on the pulmonary blood volume response to intravascular volume loading.


METHODS
Changes in pulmonary lung volume were measured from radioactive counts over the lung during radionuclide ventriculography. Baseline measurements, and repeat measurements after infusion of 21 ml.kg-1 of the dog's own blood, were made both before and after a pericardiectomy.


METHODS
Ten closed chest, anaesthetised dogs were studied.


RESULTS
Prior to and following pericardiectomy, volume loading produced equivalent and significant increases in left atrial, mean pulmonary artery, and right atrial pressures (all p less than 0.05). Before pericardiectomy, radionuclide lung counts increased from 1606(SEM 348) to 1870(402) with volume loading, corresponding to a 16% rise in lung counts from baseline (p less than 0.05). Following pericardiectomy, a similar volume load did not result in a significant rise in lung counts [1588(245) to 1697(255), 9%, p = 0.16], but was accompanied by an increase in left ventricular diastolic volume, from 39.7(6.6) to 58.7(6.4) ml, p less than 0.05, and a decrease in systemic vascular resistance index, from 122,600(14,600) to 86,600(10,000) dynes.s.cm-5 x kg, p less than 0.05.


CONCLUSIONS
These data support the concept that removal of the pericardium is accompanied by reduced pulmonary blood volume overload in response to intravascular volume loading. The mechanism appears to be related to improved left ventricular diastolic filling, perhaps the result of diminished ventricular interaction, and to redistribution of excess intravascular volume from the pulmonary to the systemic circuit.
Gerson
M C
MC
University of Cincinnati Medical Center, Department of Medicine, Cincinnati, Ohio 45267-0542.
Gabel
M
M
Fowler
N O
NO
White
M
M
D000818:Animals; D001794:Blood Pressure; D001810:Blood Volume / Q000502:physiology*; D004285:Dogs; D005260:Female; D008176:Lung Volume Measurements; D008297:Male; D010496:Pericardium / Q000502:physiology* / Q000601:surgery; D011651:Pulmonary Artery / Q000502:physiology*; D014655:Vascular Resistance