The combined effect of halothane-induced hypotension and hypocapnia on canine myocardial blood-flow and oxygen consumption.
In eleven intact mechanically ventilated dogs anaesthetized with pentobarbitone, mean arterial pressure was reduced to 55% of the control value by ventilating with 1-1.5% halothane. At normocapnia this resulted in decreases in myocardial blood-flow and oxygen consumption to 47% and 55% of their respective control values and an increase in myocardial vascular resistance to 123% of control value. When hypocapnia (mean PaCO2=26 mm Hg) was superimposed on hypotension, myocardial blood-flow was further decreased to 38% of control value whereas oxygen consumption did not alter significantly. When halothane was discontinued, allowing recovery from hypotension, the rate of recovery of myocardial blood-flow and cardiac output was much slower than that of arterial pressure.
D000818:Animals; D001783:Blood Flow Velocity; D001811:Blood Volume Determination; D002245:Carbon Dioxide / Q000097:blood*; D002302:Cardiac Output / Q000187:drug effects; D003326:Coronary Circulation / Q000187:drug effects*; D003864:Depression, Chemical; D004285:Dogs; D006221:Halothane / Q000009:adverse effects*; D007022:Hypotension / Q000139:chemically induced* / Q000378:metabolism; D009206:Myocardium / Q000378:metabolism*; D010100:Oxygen / Q000097:blood; D010101:Oxygen Consumption / Q000187:drug effects*; D010313:Partial Pressure; D014655:Vascular Resistance / Q000187:drug effects
D002245:Carbon Dioxide; D010100:Oxygen; D006221:Halothane