title: Porcine systemic and regional organ blood flow during 1.0 and 1.5 minimum alveolar concentrations of sevoflurane anesthesia without and with 50% nitrous oxide.
abstract: Effects of sevoflurane anesthesia on organ blood flow were examined in nine healthy isocapnic pigs using 15-mumol diameter radionuclide-labeled microspheres that were injected into the left atrium. Minimum alveolar concentration (MAC) of sevoflurane required to prevent 50% of the pigs from responding by gross purposeful movement to a noxious stimulus was found to be 2.66 +/- 0.20%. Hemodynamic measurements were made on each pig during the following five conditions: awake (control); 1.0 MAC of sevoflurane anesthesia; 2.66% (1.0 MAC) sevoflurane + 50% N2O anesthesia; 1.5 MAC of sevoflurane anesthesia; and 3.99% (1.5 MAC) sevoflurane + 50% N2O anesthesia. Dose-related decrease in cardiac output, mean aortic pressure and left ventricular work occurred with sevoflurane anesthesia but heart rate was unchanged. Addition of 50% N2O to either of the pre-established sevoflurane concentrations did not change heart rate or the cardiac output, but with 3.99% sevoflurane mean aortic pressure decreased further. Unlike isoflurane and halothane which increase porcine brain blood flow, cerebral blood flow decreased to a similar level with both levels of sevoflurane anesthesia. Whereas cerebellar perfusion was unaltered with both levels of sevoflurane anesthesia, brain-stem blood flow decreased to a similar level from the control value. However, during 3.99% sevoflurane anesthesia, brain-stem blood flow exceeded that at 2.66% sevoflurane anesthesia. Addition of N2O to pre-established concentrations of sevoflurane increased regional brain blood flow but cerebral and brain-stem blood flow exceeded awake value only during 2.66% sevoflurane + 50% N2O anesthesia. Transmural myocardial blood flow decreased in a dose-dependent manner during sevoflurane anesthesia but the subendocardial/subepicardial perfusion ratio remained at control value.(ABSTRACT TRUNCATED AT 250 WORDS)
mesh_terms: D000311:Adrenal Glands / Q000098:blood supply; D000758:Anesthesia; D000777:Anesthetics / Q000494:pharmacology; D000818:Animals; D002560:Cerebrovascular Circulation / Q000187:drug effects; D003326:Coronary Circulation / Q000187:drug effects; D004987:Ethers / Q000008:administration & dosage* / Q000494:pharmacology; D006439:Hemodynamics / Q000187:drug effects; D008738:Methyl Ethers; D009609:Nitrous Oxide / Q000008:administration & dosage* / Q000494:pharmacology; D012039:Regional Blood Flow / Q000187:drug effects; D012079:Renal Circulation / Q000187:drug effects; D000077149:Sevoflurane; D013152:Splanchnic Circulation / Q000187:drug effects; D013552:Swine
chemical_list: D000777:Anesthetics; D004987:Ethers; D008738:Methyl Ethers; D000077149:Sevoflurane; D009609:Nitrous Oxide