The Effect of Hypercapnia on Estimated Hepatic Blood Flow, Circulating Splanchnic Blood Volume, and Hepatic Sulfobromophthalein Clearance During General Anesthesia in Man*
Year: 1961
Type: article
Abstract: Splanchnic circulatory adjustments during gen-eral anesthesia in man are difficult to assess in the absence of precise information regarding the depth of anesthesia and the regulation of gas exchange. The vasoconstriction responsible for the fall in hepatic blood flow that has been reported by several investigators (1, 2) may be attributable to the anesthetic agents themselves, to changes in venous return following reduction in activity and tone of skeletal muscles (3), to hypoxia or to hypercapnia. Of all of these the last has been par-ticularly difficult to detect and control (4). Now, however, the availability of satisfactory muscle relaxants (5) and the development of mechanical devices for the maintenance of a suitable respira-tory pattern (6) have made it possible to achieve constancy in anesthetic level, oxygenation, and carbon dioxide elimination. Comparable "steady state " measurements of splanchnic hemodynamic parameters can be made before and during hyper-capnia, because ventilatory excursion and rate can be fixed by artificial respiration after the adminis-tration of neuromuscular blocking agents, and the arterial carbon dioxide content can be altered as desired by appropriate changes in the breathing mixture. Under these circumstances, the volume of blood held within the splanchnic vasculature is determined only by local venomotor activity and by the balance between arteriolar resistances. In-terference by variations in intra-abdominal pres-* This work was supported by grants from the De-partment of the Army (Contract DA-49-007-MD-205),
DOI: 10.1172/jci104288
Language: English
Subfield: Anesthesiology and Pain Medicine
Field: Medicine
Domain: Health Sciences
Open Access status: bronze
Funder: U.S. Public Health Service
OpenAlex ID: W2164097253