Anesthesia and analgesia
-
Anesthesia and analgesia · Sep 1995
Comparative StudyComparison of needle deviation during regional anesthetic techniques in a laboratory model.
Although many characteristics of needles used for spinal and epidural anesthesia have been studied extensively, the amount that a needle deviates from a straight path while passing through tissue has been relatively ignored. A laboratory model was used to determine the amount of needle deviation produced when different types of new spinal needles and epidural needles were passed through porcine tissue. ⋯ Needles commonly used for epidural anesthesia (Tuohy, Hustead, Crawford) exhibited increased deviation (range 1.73-3.54 mm/50 mm tissue), although the largest amount was seen with beveled spinal needles (Quincke, Atraucan) (range 4.42-5.90 mm/50 mm tissue). The possible clinical significance of needle deviation during the performance of a regional anesthetic is discussed.
-
Anesthesia and analgesia · Sep 1995
Effects of extracorporeal circulation on renal function in coronary surgical patients.
We prospectively studied perioperative changes of renal function in 12 previously normal patients (plasma creatinine < 1.5 mg/dL) scheduled for elective coronary surgery. Glomerular filtration rate (GFR) and effective renal plasma flow (ERPF) were measured with inulin and 125I-hippuran clearances before induction of anesthesia, before cardiopulmonary bypass (CPB), during hypo- and normothermic CPB, after sternal closure, and 1 h postoperatively. Renal and systemic vascular resistances were calculated. ⋯ Urine NAG, creatinine, and free water clearances were normal in all patients both pre- and postoperatively. Osmolal clearance and fractional excretion of sodium increased postoperatively from 1.54 +/- 0.06 to 12.47 4/- 11.37 mL/min, and from 0.44 +/- 0.3 to 6.07 +/- 6.27, respectively. We conclude that renal function does not seem to be adversely affected by CPB.(ABSTRACT TRUNCATED AT 250 WORDS)
-
Anesthesia and analgesia · Sep 1995
Factors affecting the concentration of compound A resulting from the degradation of sevoflurane by soda lime and Baralyme in a standard anesthetic circuit.
Carbon dioxide absorbents, such as soda lime and Baralyme brand absorbent, convert sevoflurane to CF2 = C(CF3)OCH2F, a vinyl ether called "Compound A," whose toxicity raises concerns regarding the safety of sevoflurane in rebreathing circuits. Because an increased inflow rate to an anesthetic circuit decreases rebreathing, we assumed that an increased rate would proportionately decrease the concentration of Compound A. In the present report, we measured the Compound A concentration resulting from the action of wet (standard) soda lime and wet (standard) Baralyme on 2% sevoflurane in a model anesthetic circuit, using inflow rates (0.5, 1.0, 2.0, 4.0, and 6.0 L/min), ventilations (5 and 10 L/min), and carbon dioxide production/removal (200 and 400 mL/min) found in clinical practice. ⋯ An increase in ventilation increased the concentration of Compound A, having a much greater effect at high rather than low inflow rates. An increase in amount of carbon dioxide absorbed also increased the concentration of Compound A. We conclude that inflow rate, ventilation, and carbon dioxide production are major determinants of the concentration of Compound A.
-
Anesthesia and analgesia · Sep 1995
Comparative StudyAnesthesiology critical care medicine fellowship training.
Anesthesiology critical care medicine (ACCM) fellowship training was accredited in 1989, and a small number of graduating anesthesiology residents pursue this additional training. Considering the flexible program guidelines of the American Board of Anesthesiology (ABA), we hypothesized that ACCM fellowship training programs varied significantly among the 42 institutions accredited to offer this program. This study of ACCM fellowship programs used a six-part, 57-item questionnaire completed by 36 program directors to describe six aspects of the program: institution size, program director, attending staff, fellowship applicants, curriculum, and the role of the American Society of Critical Care Anesthesiologists (ASCCA). ⋯ Fellowship curricula had varied requirements for research, intraoperative anesthesia, and ICU procedures performed by the fellow. In general, program directors believe that salary and on-call responsibility are not important issues for applicants. Nineteen percent of program directors train ACCM fellows longer than the 12 mo required by the ABA and believe that ACCM training should be lengthened.
-
Anesthesia and analgesia · Sep 1995
Comparative StudyIntrathecal administration of liposomal morphine in a mouse model.
The authors determined the duration of analgesia, toxicity, and neuraxial distribution of liposomal morphine after intrathecal administration in the mouse. Analgesic duration was determined using the tail-flick test after intrathecal injection of 12.5, 25, or 50 micrograms of plain or liposomal morphine (n = 6 mice/dose/formulation). Toxicity of the formulations was compared by estimating LD50. ⋯ For plain morphine, the drug was not confined to a specific neuraxial segment, and segmental levels declined rapidly. After liposomal morphine, the most morphine was concentrated and persisted in the low spinal cord segment at each time interval. These results show that a single dose of liposomal morphine produces prolonged analgesia with decreased toxicity compared to the plain formulation.