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THE EFFECT OF INTRAVENOUS INFUSION OF HYPEROSMOTIC SODIUM AND POTASSIUM CHLORIDE SOLUTIONS ON CEPHALIC BLOOD FLOW IN CONSCIOUS SHEEP
Author(s) -
Beal A. M.
Publication year - 1976
Publication title -
quarterly journal of experimental physiology and cognate medical sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.925
H-Index - 101
eISSN - 1469-445X
pISSN - 0033-5541
DOI - 10.1113/expphysiol.1976.sp002362
Subject(s) - blood flow , chemistry , potassium , sodium , renal blood flow , medicine , endocrinology , anesthesia , hemodynamics , organic chemistry
The rate of flow of plasma and blood through the head of conscious sheep was measured before, during and after the intravenous infusion of 1 mol.l –1 NaCl and 1 mol.l –1 KCl at 0·8–1·0 ml. min ‐1 for 2 hours. The plasma flow was estimated by indicator‐dilution technique using sodium para‐aminohippurate which was shown to be a satisfactory indicator substance. Short periods of rumination were found to cause marked increases in cephalic blood flow. The infusion of hyperosmotic sodium chloride caused no consistent changes in the rates of cephalic plasma flow and blood flow. During potassium infusion plasma and blood flows increased as the plasma potassium concentration increased up to approximately 6 mmol.l –1 . Further increases in plasma potassium concentration were associated with a progressive return of these flow rates to or below the preinfusion levels. This pattern of change in the rate of plasma flow through the head of the sheep was very similar to that previously reported for renal plasma flow during hyperkalaemia in conscious sheep. At its maximum the cephalic plasma flow was 1·163±0·029 (S.E. of mean) times the pre‐infusion flow rate. Cephalic blood flow tended to reach maximum rates at slightly higher plasma potassium concentrations and thereafter, to fall more slowly than the plasma flow due to concomitant increases in haematocrit. Maximum cephalic blood flow was 1·176±0·032 times the preinfusion flow rate. The lowest rates of cephalic plasma and blood flow occurred during the first 30 minutes following cessation of potassium infusion.