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Biomedical subjects

H W Linde

Publications and source records attributed to H W Linde.

At least 19 recordsLinked to original sources
PubMed1986

Status of women in academic anesthesiology.

The authors compared anesthesia faculties with the rest of medical school faculties at each of four academic ranks and found a significant difference in proportion of men and women anesthesia faculty members at the assistant professor rank only (P less than 0.001). When the faculty status of women and men academic anesthesiologists was examined a significant difference was found in rank distribution in age groups 40 to 44 (P less than 0.005) and 45 to 49 (P less than 0.001), where there was a deficit of professors and a surfeit of instructors among women. Significant differences in distribution continued at age 50-54 (P less than 0.01), 55-59 (P less than 0.001), and 60-64 (P less than 0.005), primarily at professor and assistant professor ranks. In addition, there was significantly lower prevalence of board certification (P less than 0.001) and level of responsibilities for women (P less than 0.001). There was no significant difference in tenure status.

Adult↗
PubMed1984

Renal tissue oxygenation following induced hypotension in dogs.

Renal oxygenation was studied during induced hypotension in mongrel dogs, anaesthetized with 1-1.5% halothane in oxygen. Hypotension was induced with an infusion i.v. of sodium nitroprusside (SNP) 70 +/- 17 micrograms kg-1 min-1 (mean +/- SEM) or trimetaphan (TMP) 36 +/- 16 micrograms kg-1 min-1, or by controlled arterial haemorrhage (45 +/- 6 ml/kg of body weight). Mean arterial pressure (MAP), cortical (Pcto2) and medullary (Pmto2) tissue oxygen tensions, arterial (Pao2), renal venous (Prvo2), and urine (Puo2) oxygen tensions were measured during the 40-min control, hypotension, and recovery periods. MAP was decreased to approximately 60% of the control value. Pcto2 decreased significantly (P less than 0.05) in all three groups while Pmto2 decreased significantly only in the haemorrhage group. Upon restoration of MAP to normal values, renal tissue oxygen tensions recovered in all groups, somewhat more rapidly in the SNP group. There were no significant differences in Pao2, Prvo2, and Puo2 during control, hypotension and recovery periods in the three groups. Tissue oxygen tension values followed the changes in MAP, but were not hypoxic, leading us to believe that both SNP and TMP are hypotensive agents safe for the kidney.

Animals↗
PubMed1984

Vaporization of mixed anesthetic liquids.

The results of erroneous filling of agent-specific anesthetic vaporizers were studied. The fraction of gas flow through the vaporizer was calculated for three vaporizers set to deliver essentially equipotent final concentrations: halothane, 1% (1.25 MAC); enflurane, 2% (1.19 MAC); and isoflurane, 1.5% (1.30 MAC). These fractional flows, at 22 degrees C, were 0.0188 for 1% halothane, 0.0615 for 2% enflurane, and 0.0295 for 1.5% isoflurane. Concentrations were calculated for cases of total filling of a vaporizer with one of the other two agents. In terms of potency of delivered agent, fourfold underdoses or overdoses could result from such errors. Refilling a 25% full vaporizer with the wrong agent then was considered. In order to calculate the concentrations of each agent that would be delivered in such a case, vapor pressures of each were determined in mixtures of two agents. Enflurane and isoflurane could not be separated satisfactorily by gas chromatography. Halothane, when mixed with enflurane or isoflurane, enhanced vaporization of each agent, as well as being somewhat more easily vaporized itself. Halothane, enflurane, and isoflurane do not form ideal solutions when mixed and the resultant vapor concentrations of each of two agents when mixed may be far from those predicted by an assumption of ideality.

Anesthesia, Inhalation↗
PubMed1983

High-performance liquid chromatographic assay for etomidate in human plasma: results of preliminary clinical studies using etomidate for hypnosis in total intravenous anesthesia.

A sensitive and specific high-performance liquid chromatographic assay was developed for the measurement of etomidate in human plasma following extraction of the drug and the internal standard. Using 0.5-ml aliquots of plasma, the assay was linear in the concentration range of 20-2000 ng of etomidate/ml of plasma. This method was used to evaluate a preliminary clinical study of an etomidate infusion regimen for hypnosis in a total intravenous anesthesia protocol in 23 patients. The average duration of the infusion was 30 min, and awakening and alertness occurred 20 and 36 min after the termination of the infusion, respectively, at the respective plasma concentrations of 297 and 214 ng/ml. These results and this assay will be used to design and evaluate an improved etomidate infusion regimen.

Anesthesia, Intravenous↗
PubMed1981

Morphologic changes in mouse spermatozoa after exposure to inhalational anesthetics during early spermatogenesis.

The authors studied anesthetic mutagenesis following exposure in vivo by use of an adaptation of the mouse spermatozoa morphology assay of Wyrobek and Bruce. The epididymal spermatozoa of (C57B1/C3H)F1 mice were examined for morphologic abnormalities following exposure to near-0.1 MAC and greater concentrations of general anesthetics. Twenty exposure hours (4 hr/day x 5 days) were conducted for nitrous oxide, diethyl ether, chloroform, trichlorethylene, halothane, methoxyflurane, enflurane, and isoflurane, each at two concentrations. Twenty-eight days after exposure, epididymal spermatozoa were examined. Statistically significant increases in the percentages of abnormal spermatozoa were found for chloroform, trichloroethylene, and enflurane, compared with controls. These data suggest that direct examination of reproductive cells following exposure to general anesthetics in vivo may be useful in the investigation of the genetic toxicities of these compounds.

Anesthetics↗
PubMed1981

Causes of death among anesthesiologists: 1930-1946.

The causes of death among anesthesiologists from 1930 through 1946 were determined and compared to the causes of death for contemporaneous physicians as well as anesthesiologists in later eras. Names of US white male anesthesiologists listed in the annual Directories of Anesthetists compiled by the International Anesthesia Research Society were searched for in the death files of the American Medical Association. Among those listed in the Directories 274 deaths were located. Causes were ascertained for 269 deaths and 259 causes were verified from death certificates. The leading causes of death of anesthesiologists and other physicians of the same era were cardiovascular-renal diseases and malignant neoplasms. The death rate from all causes was lower among anesthesiologists than among contemporaneous white men and other physicians. Death rates among anesthesiologists from 1930-1946 were similar to those among anesthesiologists in 1947-1956, but greater than those for 1957-1971. Among deaths from malignant neoplasms, those of the digestive organs were the most frequent and those of the respiratory tract the least. Anesthesiologists practicing in the earlier part of this century had lower death rates and they were less likely to die of malignant neoplasms than contemporaneous white men. The death rates for these anesthesiologists were similar to those for anesthesiologists during 1947-1956, but greater than rates observed for anesthesiologists during 1957-1971. This suggests that exposure to the fluorinated anesthetic agents introduced in the mid-1950s may not be an important health hazard.

Adult↗
PubMed1980

Postdural puncture headache in patients with chronic pain.

The incidence of headache after dural puncture in patients being treated for chronic pain was studied prospectively. Dural punctures were performed in 142 patients and headache developed in 13 (9.2%). Four of 32 patients (12.5%) who underwent diagnostic differential spinal and nine of 110 patients (8.2%) given intrathecal steroid injection developed headache. There was a 10.7% incidence of headache when a 22-gauge needle was used as compared to 5% with a 25-gauge needle. This difference was not statistically significant. The incidence decreased with increasing age. The incidence of postdural puncture headache in chronic pain patients does not differ significantly from that previously reported for surgical patients. All patients who developed headache responded to treatment which consisted of intravenous and oral fluids, analgesics, bed rest, and, if necessary, epidural blood patch.

Adult↗
PubMed1978

Elevation of creatine phosphokinase in young men after recreational exercise.

Twenty healthy male volunteers were divided into four groups for a period of recreational physical exercise. Standard blood chemistry determinations were made before exercise and on the two subsequent days. Creatine phosphokinase (CPK), SGOT, and lactic dehydrogenase levels were transiently elevated, but the change was considered significant only in the CPK level after certain types of exercise. Persons having these determinations performed should be questioned about recent physical exertion in the event of abnormal laboratory results.

Adult↗