摘要:

The effects of high-dose fentanyl-oxygen anesthesia (100 μg/kg) on myocardial blood flow (argon washin), myocardial oxygen consumption, myocardial lactate balance, and cardiovascular dynamics were studied in nine patients undergoing three-vessel coronary artery bypass operations. All patients had been on maintenance doses of a beta-receptor blocker (pindolol). Except for pindolol all medication had been discontinued 48 hours prior to the study. Measurements were performed in the awake state, after 10 μg/kg fentanyl, after 100 μg/kg fentanyl, and during sternotomy. Moderate doses of fentanyl (10 μg/kg) produced minimal changes in myocardial blood flow, myocardial oxygen consumption, and cardiovascular dynamics; myocardial oxygen balance was well maintained. Large doses of fentanyl (100 μg/kg) produced a 16 per cent decrease in mean aortic pressure, cardiac index did not change significantly, while stroke volume index decreased by 23 per cent. Myocardial oxygen consumption decreased by 14 per cent and myocardial blood flow by 10 per cent. Myocardial lactate production was observed in five patients, indicating myocardial ischemia. During sternotomy arterial pressure and heart rate increased 8 per cent and 29 per cent, respectively, resulting in an increase in myocardial work, as reflected by a 38 per cent increase in myocardial oxygen consumption and by a 54 per cent increase in myocardial blood flow. Myocardial lactate production was observed in seven of nine patients. Our data demonstrate that in patients on maintenance doses of beta-receptor blockers, large doses of fentanyl as the sole “anesthetic” produce incomplete anesthesia and fail to protect the myocardium from ischemia due to noxious stimuli during coronary artery surgery.

ISSN:0003-3022    

出版商:OVID    

年代:1982

数据来源: OVID

摘要:

Different doses of epidural morphine were studied in order to determine their effectiveness in providing postoperative pain relief after surgery of the lower extremities and their relationship to the incidence of untoward reactions. The study was carried out in a double-blind fashion using five dosages of epidural morphine (0.5, 1.0, 2.0, 4.0, and 8.0 mg) and included 60 patients. The higher doses of morphine (2.0, 4.0, and 8.0 mg) were equally effective and more effective than the lowe: doses (0.5 and 1.0 mg) in providing postoperative analgesia. Nausea and vomiting were encountered more frequently with the highest dose (8.0 mg) and this finding was statistically significant (P< 0.03). No statistically significant difference was found between the doses studied with regard to itching, urinary retention, and respiratory depression; the latter was evaluated in a subgroup of 20 patients. These data suggest that effective postoperative pain relief after surgery of the lower extremities can be achieved with relatively low doses of morphine sulfate and with minimal side effects. For the type of surgery studied, 2 mg morphine sulfate appeared to be the optimum dose.

ISSN:0003-3022    

出版商:OVID    

年代:1982

数据来源: OVID

摘要:

Cerebral blood flow (CBF) and cerebral oxygen consumption (CMRo2) were measured in young (4 months) and aged (24–26 month) spootaneously hypertensive (SHR) rats and Wistar Kyoto (WKY) controls under control anesthetized conditions (70 per cent N2O, 30 percent O2) and during hypotension induced with intravenous sodiumnitroprusside (SNP) infusions. CBF was measured with radio-active microspheres and cerebral arterial-venous blood O2measurements were determined from arterial and sagittal sinus blood samples. Arterial blood PCO2was maintained at approximately 35 mmHg and body temperature at 37°C. Under control conditions blood pressure was increased in SHR but there was no significant difference in CBF or CMRO2between SHR and WKY or young and aged rats. CBF and CMRo2were maintained in WKY when mean blood pressure was decreased to 65 mmHg with SNP infusion. CBF was significantly decreased in young and aged hypertensive rats during SNP-induced hypotension. CMRo2was also decreased in both young and aged hypertensive animals. These results support previous reports that SNP-induced hypotension will maintain CBF and CMRo2in normotensive subjects, but suggest that the direct cere-brovasodilating effects of SNP are moderate and will not reverse the cerebrovascular changes induced by chronic hypertension.

ISSN:0003-3022    

出版商:OVID    

年代:1982

数据来源: OVID

摘要:

Ten healthy males between 18 and 33 years received 10 mg morphine sulfate intravenously, or by lumbar epidural injection at two sessions 2–4 weeks apart, in random sequence. The following observations were made at intervals for 22 h. (1) Segmental hypalgesia to ice and pin scratch. (2) Cold pressor response test in hand and foot as an index of analgesia. (3) Time of onset and duration of side effects. (4) Serum concentrations of morphine. Few non-respiratory changes were seen after intravenous morphine. Cold pressor response was unchanged in hand and foot, no segmental hypalgesia or itching occurred, and only one subject complained of nausea. Marked changes occurred after epidural morphine. Cutaneous hypalgesia to ice and pin scratch appeared in the thoracolumbar region in all subjects. In six subjects hypalgesia rose to the midthoracic region during the second or third hour and to the trigeminal distribution between the sixth and ninth hour in five subjects. Cold pressor response fell rapidly in the foot during the first 1.5 h after epidural morphine, and a little later cold pressor response also fell in the hand in all subjects, and remained depressed for the duration of the experimental period. Pruritus occurred at three hours in nine of the 10 subjects, nausea at about four hours in six of the subjects, and vomiting at about six hours in five of the subjects. Hypalgesia and side effects were not related to serum concentrations of morphine. These results suggest that lumber epidural morphine travels cephalad in the cerebrospinal fluid to reach the brain stem and fourth ventricle by the sixth hour.

ISSN:0003-3022    

出版商:OVID    

年代:1982

数据来源: OVID

摘要:

Ketamine produces both excitatory and depressant actions in the brain, but there have been conflicting results regarding which structures are affected and the magnitude of the alteration in cerebral metabolism produced. The authors applied the 2-[14C]deoxyglucose method quantitatively to a study of ketamine anesthesia (10 or 30 mg/kg intravenously) in the rat. Ketamine caused both increases and decreases in local cerebral glucose utilization. The areas with altered glucose utilization could be grouped into functional systems. Some structures of the limbic system showed large increases in glucose utilization; indeed the 70 per cent increases in cingulate gyrus and hippocampus were the largest of all regions examined. The extra-pyramidal motor system and corpus callosum showed significant but less dramatic (20–40 per cent) increases. On the other hand, decreased metabolism occurred in the somatosensory and auditory systems, with the greatest reduction (40 per cent) in the inferior colliculus. Within some structures, such as the caudate nucleus and visual cortex, a striking redistribution of metabolism which is characterized by a change in the autoradiographic pattern of activity was noted.Reduced glucose utilization in the somatosensory and auditory systems suggests that a selective sensory deprivation occurs during ketamine anesthesia while the increased metabolism in the limbic system is consistent with neurophysiologic studies which have demonstrated seizure activity in this region. Compared with other anesthetics, which tend to produce a generalized decrease in metabolism, the cerebral metabolic effects of ketamine are unique and emphasize that it produces a state of “anesthesia” which is quite different from that of other commonly used drugs.

ISSN:0003-3022    

出版商:OVID    

年代:1982

数据来源: OVID

摘要:

The authors investigated the cardiovascular and regional hemo-dynamic changes that occur in the aged rat under unanesthetized control conditions and during the induction of halothane anesthesia. Regional blood flow changes were measured in young (4-month-old) and aged (27–29-month-old) F-344 rats using radioactive microspheres under unanesthetized conditions and during three levels of halothane anesthesia. Blood halothane levels were measured at each anesthetic level. The inspired concentrations of halothane were adjusted in youngvs. aged rats so that each group was tested at the same depth of anesthesia. Results indicate that aged rats had significantly lower blood pressures than young rats in an unanesthetized state and at all levels of halothane anesthesia. Tissue blood flow was similar between young and aged rats in skeletal muscle and skin, while blood flow to renal and small intestinal tissues was consistently higher in young rats. Heart blood flow was initially 100 per cent higher in young rats but decreased to similar levels as aged at the highest levels of halothane anesthesia used. Cerebral blood flow was similar initially in youngvs.aged, but increased in young rats with deeper levels of halothane anesthesia while decreasing in aged rats. These results indicate significant regional hemodynamic differences in young compared to aged rats under unanesthetized conditions as well as in response to halothane anesthesia.

ISSN:0003-3022    

出版商:OVID    

年代:1982

数据来源: OVID

摘要:

Thirty adults undergoing elective superficial surgery under enflurane-nitrous oxide anesthesia while intubated and breathing spontaneously via a modified Mapleson D (Bain) T-piece circuit were studied with their consent. Total fresh gas flows which were initially high were adjusted downward until minimal rebreathing (inspired CO2tension of 5 to 10 mmHg) was present. At this point both fresh gas flow (VF) and minute volume (VE) were recorded, and the ratio of the two (VF/VE) was calculated. The mean VF/VEratio was found to be 1.89 ± 0.27 (SD).Linear regression was used to plot VFagainst VE, breathing frequency, tidal volume, age, weight, and end-tidal CO2tension. Significant correlation was found only with VE(r2= 0.48,P< 0.001) and frequency (r2= 0.44,P< 0.001). When the ratio VF/VEwas plotted against the same variables, no significant correlation was found.This study showed a wide variability in the minimum VF/VEratio which prevents rebreathing. The respiratory waveform, which was not studied, probably played a role in determining the VF/VE. Nevertheless, 87 per cent of our patients required a VF/VEratio of 2.0 or less to prevent rebreathing.If one is especially concerned about rebreathing, VEshould be measured and the VFadjusted to about twice the measured VE.

ISSN:0003-3022    

出版商:OVID    

年代:1982

数据来源: OVID

摘要:

The effects of intravenously administered midazolam on cerebral blood flow were evaluated in eight healthy volunteers using the133Xe inhalation technique. Six minutes after an intravenous dose of 0.15 mg/kg midazolam, the cerebral blood flow decreased significantly (P< 0.001) from a value of 40.6 ± 3.3 to a value of 27.0 ± 5.0 ml 100 g−1. min−1. Cerebrovascular resistance (CVR) increased from 2.8 ± 0.2 to 3.9 ± 0.6 mmHg/(ml.100 g−1. min−1) (P< 0.001). Mean arterial blood pressure decreased significantly (P< 0.05) from 117 ± 8 to 109 ± 9 mmHg and arterial carbon dioxide tension increased from 33.9 ± 2.3 to 38.6 ± 3.2 mmHg (P< 0.05). Arterial oxygen tension remained stable throughout the study, 484 ± 95 mmHg before the administration of midazolam and 453 ± 76 mmHg after. All the subjects slept after the injection of the drug and had anterograde amnesia of 24.5 ± 5 min. The decrease in mean arterial blood pressure was probably not important since it remained in the physiologic range for cerebral blood flow autoregulation. The increase in arterial carbon dioxide tension observed after the midazolam injection may have partially counteracted the effect of this new benzodiazepine on cerebral blood flow. Our data suggest that midazolam might be a safe agent to use for the induction of anesthesia in neurosurgical patients with intracranial hypertension.

ISSN:0003-3022    

出版商:OVID    

年代:1982

数据来源: OVID

摘要:

It is a common practice for anesthetists to substitute for one another, especially for short breaks during long surgical procedures. The assets and liabilities of this practice of relief have not been examined previously. In the course of gathering 1,089 reports of preventable errors and failures associated with anesthesia management, we identified 96 which involved a relief anesthetist. This subset was examined in search of common characteristics and patterns of cause and discovery of errors.In 28 incidents, the relief anesthetist discovered an error or the cause of an error. In 10 incidents, the process of relief was identified as having contributed to the commission of an error. Although 70 of the 1,089 incidents were associated with substantive negative outcomes,e.g.,death, cardiac arrest, or extended ICU stay, none of those incidents was caused by a relieving anesthetist. There is a strong implication that relief is beneficial more often than not even aside from the presumed beneficial effect on the vigilance of the primary anesthetist (the latter effect was outside the scope of this study). From the descriptions of the causes and discoveries of errors in these relief-related incidents, guidance can be drawn for the safe and effective conduct of the intraoperative exchange of anesthesia personnel.

ISSN:0003-3022    

出版商:OVID    

年代:1982

数据来源: OVID

摘要:

A modification of the Ames bacterial assay system employing two histidine-dependent strains ofSalmonella lyphimurium, TA1535 and TA100, was used to test the mutagenicity of four experimental, inhalational anesthetic agents: sevoflurane, synthane, dioxychlorane, and dioxyflurane. None of the anesthetics was mutagenic. Increased activity was seen only with vinylidene chloride, the positive control.

ISSN:0003-3022    

出版商:OVID    

年代:1982

数据来源: OVID