Effects of isoflurane-nitrous oxide anaesthesia on insulin secretion in female patients.

In vitro studies suggest that volatile anaesthetic agents may directly inhibit insulin secretion. It is unclear if supplementation of anaesthesia with isoflurane impairs insulin secretion. We performed a 5-g i.v. glucose tolerance test in 21 patients before and during anaesthesia which was maintained with either 1 or 2 MAC of isoflurane in nitrous oxide, or no volatile agent. The study was carried out before surgery to avoid the influence of hormonal responses to trauma. A significant glycaemic response occurred during both i.v. glucose tolerance tests in all three groups of patients. Serum insulin concentrations were measured and the acute increase in insulin concentration at 3 min and area under the curve for 15 min were calculated. Both variables decreased significantly in all three groups during the tests performed under anaesthesia compared with tests carried out before anaesthesia.

Factors associated with mothers selecting general anesthesia for lower segment caesarean section.

The objective of the study was to investigate the sociodemographic and psychological factors which are associated with choice or refusal of regional anesthesia for lower segment Caesarean section. A semi-structured questionnaire was administered preoperatively to consecutive women presenting for elective operation at two hospital sites in the same health authority. The questionnaires were administered to 39 pregnant women by two anesthetists, one at each site. Sociodemographic and past and present obstetric and anesthetic details were obtained. The Hospital Anxiety and Depression scale and the FEAR questionnaire were used with an additional visual analog scale to assess fearfulness associated with the proposed operation. A 'panic checklist' of ten items was also constructed to identify procedures associated with feelings of panic. Ten women requested general anesthesia. These women had a similar level of anxiety to the others, but were significantly more depressed, had had more pregnancies overall and more without live babies. There were also more aspects of the procedure at which they thought they might panic. Women who have suffered the loss of a conception with its associated grief and often obstetric intervention are more reluctant to be conscious during an operative delivery for a subsequent baby. Preventive measures should be considered at the time of fetal loss to avoid this. However, preoperatively a simple visual analog scale for fearfulness would identify these women so that any unresolved fears could receive full psychological assessment.

Comparison of clonidine with fentanyl on phrenic nerve activity and their interaction in anaesthetized rabbits.

We have compared the effects of clonidine and fentanyl on phrenic nerve activity in anaesthetized rabbits during artificial ventilation. Both drugs caused dose-dependent inhibition of phrenic nerve activity and complete abolition in all experiments. The calculated ED50 values were 3.7 micrograms kg-1 for clonidine and 3.9 micrograms kg-1 for fentanyl. Pretreatment with clonidine 1 microgram kg-1 i.v. depressed phrenic nerve activity to 81.8% of control values. This effect was additive with subsequent doses of fentanyl which was confirmed with an ED50 isobologram. We conclude that clonidine has the potential for deleterious respiratory effects at doses similar to those of fentanyl, but the interaction between the two drugs is additive and hence differs from their known synergistic antinociceptive interaction.

Clonidine has comparable effects on spontaneous sympathetic activity and afferent A delta and C-fiber-mediated somatosympathetic reflexes in dogs.

BACKGROUND: Clonidine, an alpha 2-adrenergic agonist, has been studied as an adjunct or alternative to spinal opioids in the management of moderate to severe pain. This study examined the relative effects of clonidine on efferent spontaneous sympathetic activity and afferent A delta and C fiber-mediated somatosympathetic responses. METHODS: Spontaneous and evoked sympathetic activity in renal sympathetic nerves, mediated by A delta and C fibers by means of supramaximal electrical stimulation of the radial and tibial nerves, were observed in anesthetized dogs. Incremental doses of clonidine were administered intrathecally or intravenously in each of five preparations followed by intravenous naloxone 2 mg and yohimbine 5 mg. RESULTS: Both spontaneous sympathetic outflow and afferent A delta- and C fiber-mediated somatosympathetic responses evoked by tibial nerve stimulation were depressed in a similar dose dependent manner by clonidine administered intrathecally or intravenously in a dose ratio of approximately 1:4. Intrathecal clonidine inhibited and eliminated both local spontaneous sympathetic outflow and tibial nerve evoked sympathetic responses but had no significant depressant effect on the radial nerve evoked sympathetic reflexes. When administered intravenously clonidine had a similar depressant effect on both radial and tibial nerve elicited reflexes and spontaneous sympathetic activity. CONCLUSIONS: Clonidine, administered intrathecally or intravenously, has a similar depressant effect on both spontaneous sympathetic outflow and afferent A delta- and C fiber-mediated somatosympathetic reflexes. When administered intrathecally it has little effect on reflexes evoked via the descending pathway by radial nerve stimulation.

Symptom reports and mortality in an occupational cohort.

The relationship between baseline symptom reports and subsequent mortality over a 24-year period was examined in a group of 1,224 white male nonsupervisory paper workers. Symptom reports were measured via the Cornell Medical Index, and the vital status of each participant was ascertained by reviewing company personnel records and death certificates. Analyses based on proportional hazards models suggest that symptom reports are predictive of mortality (RR = 1.24; P = .0002), independent of the participant's age and biologic risk status at intake. Analyses based upon age-specific and age-standardized mortality ratios confirm that the paper workers were subject to a "healthy worker effect" (standardized mortality ratio [SMR] = 0.66), and that the healthy worker effect is attenuated (SMR = 0.77) among those participants reporting ten or more symptoms at the beginning of the follow-up period.

Ischemic heart disease risk factors and twenty-year mortality in middle-age Evans County black males.

Ischemic heart disease (IHD) risk factors and 20-year mortality rates were studied in middle-aged Evans County black males. We hypothesized, a priori, that blood pressure, cholesterol, and smoking would be predictive of mortality in black males; that black-white differences in mortality would be due to differences in risk factor levels and not risk functions per se; and that social status would be associated with risk factor levels and would be a predictor of mortality. Multivariate analyses of cumulative risk of dying and time to death suggest that the major IHD risk factors are predictors of all-cause and IHD mortality in black males. Black-white differences in risk functions, specifically for cholesterol, were explained by social status: black males and lower social status white males had similar risk functions, different from those of higher social status white males. Black males and lower social status white males had almost identical survival curves, each less favorable than those of higher social status white males.