Does choice of anesthetic agent significantly affect outcome after coronary artery surgery?

A prospective study of 1094 consecutive adult patients undergoing coronary revascularization was undertaken to determine the effect of anesthetic technique on outcome. Patients received one of five primary techniques: high-dose fentanyl (greater than 50 micrograms/kg), moderate-dose fentanyl (less than 50 micrograms/kg), sufentanil (3-8 micrograms/kg), diazepam (0.4-1 mg/kg) with ketamine (3-6 mg/kg) or halothane (0.5-2.5% inspired concentration after thiopental induction). Supplemental inhalation anesthesia (enflurane, halothane, or isoflurane) was used in 60% of cases where the primary technique was intravenous based. Patients in the above anesthetic groupings had similar perioperative demographic and risk classifications. The overall incidence of postoperative myocardial infarction, postoperative low cardiac output state, and in-hospital death were 4.1, 5.6, and 3.1%, respectively. There were no significant differences in the incidence of these occurrences or in the incidence of serious pulmonary, renal, or neurologic morbidity or length of ICU stay among primary anesthetic techniques nor among supplemental inhalation agent groups. Multivariate discriminant analysis of this data suggests that a multitude of factors are significantly more important than anesthetic technique as determinants of outcome after coronary artery surgery.     

Pharmacologic profile and insulin secretagogue effect of linogliride (McN-3935), a new,orally effective hypoglycemic agent

Linogliride (McN-3935) [N-(1-methyl-2-pyrrolidinylidene)-N'-phenyl-4-morpholinecarboximidamide] was selected for clinical evaluation as a potential orally effective hypoglycemic agent for treatment of noninsulin-dependent diabetes mellitus. Linogliride is structurally unrelated to sulfonylureas and biguanides. It produced a dose-dependent hypoglycemic effect in nondiabetic rats, mice, and dogs. The minimum effective oral doses that lowered fasting blood glucose levels and improved glucose tolerance were 1–5 mg/kg. Comparison of the dose-response curves from fasting rat studies showed linogliride to be approximately two times more potent than the related compound pirogliride and approximately eight times more potent than tolbutamide. Tolerance to its hypoglycemic effect did not develop in rat and dog 3-day repeat dose studies. Linogliride did not alter plasma lactic acid levels in normal and streptozotocin-induced diabetic rats, and it improved glucose tolerance whether the glucose was administered orally or parenterally. In nondiabetic rats and dogs, decreases in fasting blood glucose levels following linogliride administration were associated with elevated (two- to fourfold) plasma insulin concentrations. Linogliride was inactive in depancreatized diabetic dogs. In genetically diabetic (db/db) mice and streptozotocin-induced diabetic rats, linogliride (25–100 mg/kg p.o.) produced variable, nondose-dependent reductions of blood glucose levels, unlike the sulfonylureas, which were consistently ineffective in these diabetic rodent models. In conclusion, although the observed activity in diabetic rodent models is suggestive of a potential nonpancreatic mechanism, the experimental evidence to date indicates that the acute effectiveness of linogliride as a hypoglycemic agent is due primarily to stimulation of insulin release.     

Parathyroid hormone resistance and B cell lymphopenia in propionic acidemia

The mechanisms of hypocalcemia, recurrent infections and hypogammaglobulinemia associated with metabolic decompensation of propionic acidemia due to propionyl-CoA carboxylase deficiency have not been defined. A 7-week-old infant with this disorder presented with severe hypocalcemia and B cell lymphopenia during an episode of metabolic acidosis and hyperammonemia. Hypocalcemia (1.1 mmoll ¹) was associated with elevated serum intact parathyroid hormone (122 ng 1 ¹), hyperphosphatemia, hypophosphaturia and hypercalcuria, indicating parathyroid hormone resistance. B cell lymphopenia (20 cells μl^-1) was associated with transient neutropenia, anemia and subsequent hypogammaglobulinemia (IgG < 294mgdl^-1, IgM < 8mgdl^-1, IgA < 8mgdl ¹), while T cells were normal. Parathyroid hormone resistance and B cell lymphopenia resolved following treatment with hemodialysis, diet and carnitine. These complications may be due to interference with parathyroid hormone renal tubular action and B cell maturation/proliferation by accumulated organic acids.     

Oxygen consumption and mixed venous oxygen saturation monitoring during orthotopic liver transplantation

Mixed venous oxygen saturation monitoring has been advocated for some critically ill patients. Patients with end-stage hepatic failure have oxygen consumption rates that are lower than normal. Using the Fick equation, oxygen consumption may be calculated if mixed venous and arterial oxygen tensions (and saturations), hemoglobin, and cardiac output are determined simultaneously. This report describes a unique pattern of changes in and oxygen consumption in 7 patients undergoing liver transplantation. A previous study correlated plasma carbohydrate (glucose) levels with early hepatic graft survival. After induction, the 7 patients reported here had low oxygen consumption and high values. The oxygen consumption rates decreased to the lowest point during the anhepatic phase and rose above baseline by the end of the case. The and oxygen consumption data reported here follow the presence of presumed hepatic metabolic activity (increased CO₂ and ionized calcium). Further research must be completed to determine whether these measurements indicate early hepatic nonfunction.     

Infant growth and aorta total lipid fatty acids

Abnormal fetal and infant growth have increasingly been correlated with adult onset cardiovascular disease. To date, there is little known about the lipid fatty acid profiles in infant cardiovascular tissue. Therefore, we analysed total lipid fatty acids from thoracic and abdominal aorta intima and media from 24 normally grown sudden infant death syndrome cases. Aorta from small for gestational age (n = 2), failure to thrive from birth (n = 3), and premature (n = 1) infants were also examined. Dihomo-gamma-linolenic acid (C20:3n-6) and oleic acid (C18:1n-9) concentrations were significantly lower in the thoracic than in the abdominal aorta. Similar dietary related differences were found in the subgroup (n = 15) of infants fed on formula milks. Both abdominal and thoracic intimal arachidonic (C20:4n-6) to dihomo-gamma-linolenic acid ratios were greater in the infants with retarded growth after birth than in their normally grown counterparts. Growth restriction in infancy might disrupt the normal accretion of vascular endothelial polyunsaturated fatty acids.