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[The effect of electroacupuncture analgesia on the plasma levels of cortisol and aldosterone in orthopedic operations].

The effects of electroacupuncture on plasma cortisol and aldosterone levels in patients undergoing orthopedic operations were studied. Plasma cortisol and aldosterone levels were measured at three stages. Moderate activation of the hypothalamo-pituitary-adrenal system is considered an adjustment response of the organism to the operative trauma, with stable hemodynamic parameters. The total amount of analgetic drugs which the patients received during the postoperative period was three times lower than that in the control group given neuroleptanalgesia; during electroacupuncture analgesia (EAPA) opioids were not applied. It is considered that the use of EAPA lowers the degree of the stress reaction in surgical trauma, providing adequate analgesia and neurovegetative protection of patients during orthopedic operations and in the early postoperative period.

Aldosterone↗

[Inotropic and vasopressive drugs during anesthesia and critical care. Current data].

Recent therapeutic advances in inotropic drugs and vasipressors uses allow a reappraisal of their indications during the perioperative period. Non-catecholamines vasopressors, ephedrine and phenylephrine, are particularly suitable for treatment of abrupt peroperative arterial hypotensions as observed during induction of general and medullar anesthesias. Cardiac arrest, peroperative anaphylactoid and toxic accidents are treated with epinephrine. In non-cardiac surgery, circulatory insufficiency is usually due to a peripherical origin. Cardiogenic failure occurs in rare cases mainly in vascular surgery. Therefore dopamine remains the first amine to be used in non-cardiac surgery in conjunction with volume expansion. A cardiogenic factor is responsible for most of low-cardiac output syndromes observed after cardiopulmonary bypass for cardiac surgery. However, hypovolemia may be involved and could be undiagnosed. For these reasons, dobutamine is used because of its rapid half-life of elimination and its potent effects. Inodilators (enoximone, amrinone and milrinone) ans nex dopaminergic compound (dopexamine) are powerful vasodilators agents to be introduced with care when association of amines and current vasodilators have failed. Finally, arterial pressure has to be maintained with norepinephrine after dopamine failure. Epinephrine remains last chance.

Anesthesia, General↗

Prolonged asystole during intraoperative myocardial reperfusion: an experimental study.

It has been observed in a proportion of patients, that clinically cardiac asystole persists for a prolonged period during intraoperative reperfusion. To evaluate this phenomenon, isovolumic functional indices (left ventricular [LV] balloon) and myocardial oxygen consumption (MV02) were compared in 22 canine preparations before and after two different interventions. After 45 minutes of normothermic global ischemia, (1) the control group (N = 11) was maintained on cardiopulmonary bypass with the hearts beating empty and (2) the experimental group (N = 11) was subjected to cardioplegia reperfusion at normothermia for one hour. In contradistinction to the initial hypothesis, functional recovery was better in the experimental group compared with the controls. Significant differences were observed in recovery of LV peak developed pressure (LVPDP) (controls, 66.8 +/- 7.3% [mean +/- standard error of the mean], and experimental group, 99.5 +/- 8.9%; p less than 0.05), maximum rate of rise of LV pressure (controls, 116.6 +/- 16.2%, and experimental group, 147.7 +/- 10.1; p less than 0.05), and maximum fall of LV pressure (controls, 100.3 +/- 15.8%, and experimental group, 143.1 +/- 11.5%; p less than 0.05). Correlation between LVPDP and MVO2 was also better preserved in the experimental group (controls: r = 0.15, N = 74, p = 0.18; experimental group: r = 0.47, N = 75, p less than 0.001). Values for myocardial water content and total creatine kinase in the two groups were similar. It was concluded that prolonged asystole during intraoperative reperfusion is not detrimental; on the contrary, there is enhanced functional recovery of the myocardium similar to that seen after secondary cardioplegia.

Animals↗

[Low-concentration enflurane:study of anesthetic stability and quality of recovery].

The stability of anaesthesia and the quality of recovery obtained with low doses of enflurane were studied. Two groups of 20 patients operated for lumbar slipped disc were compared. The mean age and weight distribution of the two groups were not statistically different. Induction was the same in the two groups (diazepam, fentanyl, pancuronium and nitrous oxide). In one group, enflurane (0.4%) was added with controlled ventilation. Thiopentone was added if some spontaneous movements were observed, if arterial pressure and heart rate increased, and if the digital plethysmograph curve decreased. The quality of recovery was assessed by number-connection tests 1 and 2 h after the end of anaesthesia. Thiopentone was required five times in the group without enflurane, whilst it was never used in the group with enflurane. This difference was statistically significant (p less than 0.01) and showed a more important stability of anaesthesia when enflurane (0.4%) was used. No statistically significant difference was found in the recovery scores between the two groups 1 and 2 h after the end of anaesthesia. It was proposed that low doses of enflurane were sufficient to increase the effects of the other anaesthetic drugs without any residual effect on recovery. Low doses of enflurane could be used during anaesthesia induced with fentanyl and diazepam, giving better stability during anaesthesia without any pernicious effects on recovery.

Adult↗

Effect of halothane, enflurane and isoflurane on body temperature during and after surgery.

The superficial and deep body temperatures of 40 healthy females undergoing total abdominal hysterectomy were measured during surgery and for 4 h afterwards. The patients were allocated randomly to one of five groups and anaesthetized to produce an end-tidal concentration of 1% halothane, 1% enflurane, 2% enflurane, 1% isoflurane or 2% isoflurane. The patients received also 70% nitrous oxide in oxygen and neuromuscular blockade. The theatre temperature was maintained at 22.0 degrees C. There were significant body temperature changes during operation in all groups. The mean (SD) decrease in core temperature over 85 min was approximately 1.1 (0.3) degrees C in the 1% halothane, 2% enflurane and 2% isoflurane groups, and 0.6 (0.4) degrees C in the 1% enflurane and 1% isoflurane groups (P less than 0.05). During the recovery period the 1% halothane, 2% enflurane and 2% isoflurane groups took 2 h to rewarm to preoperative temperatures, and the rate of rewarming during this time was similar for all groups.

Adult↗

Are changes in the evoked electromyogram during anaesthesia without neuromuscular blocking agents caused by failure of supramaximal nerve stimulation?

The evoked electromyogram often decreases during anaesthesia in the absence of neuromuscular block. We have measured the electromyogram of the first dorsal interosseous muscle evoked by train-of-four stimulation of the ulnar nerve in 63 patients undergoing anaesthesia for minor surgery. We used Medicotest P-00-S electrodes, a Datex Relaxograph and a current sink in the stimulating leads in parallel with the current path through the patient. The current sink was used to shunt some of the maximum available output current from the Relaxograph while maintaining the supramaximal stimulus current passing through the patient. After 30 min of anaesthesia, when the muscle response to train-of-four was stable, the ulnar nerve stimulus current was increased by reducing the proportion shunted through the current sink. The electromyographic response did not change during the study in 13 patients. In the remaining 50 patients, the response decreased to 78.4% (SD 27.1%, range 7.5-95.0%) of baseline values over the first 20 min of anaesthesia. In 22 of these patients, the electromyographic response increased from 71.4 (SD 22.6)% to 92.3 (9.5)% of baseline responses when the stimulus current was increased by 12.3 (2.4) mA, while in the remaining 28 patients the response decreased to 83.7 (10.6)% and did not increase with increasing stimulus current. These results suggest that loss of supramaximal stimulation is partly responsible for the observed changes in the evoked electromyogram during anaesthesia.

Adult↗

Peroperative nitrous oxide does not influence recovery after laparoscopic cholecystectomy.

We have evaluated the effects of nitrous oxide on recovery following laparoscopic cholecystectomy in a prospective, randomised, double-blind study with 42 otherwise healthy patients. All patients received meperidine 1 mg/kg and atropine 6 micrograms/kg im for premedication, and anaesthesia was induced with fentanyl 2 micrograms/kg and thiopental 4-6 mg/kg. Succinylcholine was used for the intubation and muscle relaxation was achieved using vecuronium. Isoflurane with 70% nitrous oxide in oxygen and fentanyl was used for maintenance of anaesthesia in group I (n = 19), and isoflurane in air/oxygen and fentanyl in group II (n = 23). The postoperative ward staff and the surgeon evaluating the postoperative recovery were blinded to the anaesthetic technique. No differences were found in duration of operation and anaesthesia, need for postoperative analgesia or postoperative nausea treated medically. Recovery, judged by the Steward Coma Score, comprehension and collaboration, degree of sedation and orientation in time and space, was similar in the two groups. Postoperative hospital stay was 1 (1-4) day in the nitrous oxide group (median (10-90th percentiles) versus 2 (1-4) days in the air group. The time until patients were recovered, as judged by return to work and normal daily activities, was the same in the two groups: 8 (4-11) days in the nitrous oxide group and 8 (4-11) days in the air group. We conclude that nitrous oxide has no influence on recovery after laparoscopic cholecystectomy.

Adult↗

Intraoperative resource utilization in anesthesia for liver transplantation in the United States: a survey.

UNLABELLED: Among the intraoperative resources expended for liver transplantation, laboratory tests, personnel, high-flow infusion devices, high-tech monitoring equipment, and veno-venous bypass vary from institution to institution. Although of obvious interest to the anesthesia liver transplantation community and others, little is known regarding current utilization of these resources on a national level. To determine the resource utilization among liver transplantation centers in the United States, we conducted a national survey between April and July 2002. Results were stratified according to pediatric versus adult recipient populations and transplantation case volume. Of 99 centers that received the survey by mail, 66 (66.6%) responded. Pediatric liver transplantation programs were distinctly different in personnel, equipment, monitoring, and veno-venous bypass utilization when compared with adult or mixed-age programs. Among laboratory studies, statistically significant trends emerged for fewer intraoperative determinations of the activated clotting time, magnesium, and phosphate with increasing transplantation volume. The results describe national practice patterns and may be useful for programs to compare their approaches and develop clinical pathways. There is wide variation of resource use between centers. The survey results do not consistently correlate with the few recommendations found in the current literature. IMPLICATIONS: Currently no comprehensive data are available describing the intraoperative use of laboratory tests, personnel, infusion and perfusion equipment, monitoring technology, and veno-venous bypass by liver transplantation programs. These postal survey results provide an overview of utilization of these resources in anesthesia for liver transplantation.

Adult↗

The role of pre-operative state-anxiety in the determination of intra-operative neuroendocrine responses and recovery.

OBJECTIVES: The psychophysiological model of adjustment to surgery predicts associations between (1) heightened pre-operative state-anxiety and intra-operative neuroendocrine responses, (2) neuroendocrine responses and complications; and (3) heightened pre-operative state-anxiety and post-operative recovery. The present study examined these associations. METHODS: Participants were 39 patients (mean age 71.9+/-6.1 years) undergoing elective carotid endarterectomy surgery under local anaesthesia. In the week prior to surgery, patients completed baseline measures of physical and mental functioning using the MOS 36-item Short-Form Health Survey (SF-36). In addition to this, they undertook a 24-hour urine save to measure cortisol and catecholamines. Measures of state-anxiety were completed on the evening prior to surgery. A second 24-hour urine save was started at the time of anaesthetic induction. Follow-up measures of physical and mental functioning were completed 1 month following surgery. All complications were recorded during hospitalization. RESULTS: There was a significant negative association between pre-operative state-anxiety and intra-operative cortisol (r=-.52, p<or=.001). Using hierarchical regression analysis, pre-operative state-anxiety accounted for 10% of the variance in intra-operative cortisol responses after controlling for medical and demographic factors. There were no significant associations between neuroendocrine responses and complications. Pre-operative state-anxiety was a significant determinant of poorer mental functioning following surgery, explaining 10% of the variance in scores after adjusting for baseline mental functioning. CONCLUSIONS: Results from this study show increasing pre-operative anxiety to be associated with lower intra-operative cortisol responses and poorer mental functioning 1 month following surgery.

Aged↗

Physiologic responses to operation in high risk surgical patients.

Fifty-three high risk surgical patients were studied using invasive cardiorespiratory monitoring to gain physiologic perspective of the perioperative period. Multiple hemodynamic and oxygen transport variables were tracked through the preoperative, intraoperative and postoperative periods using frequent sequential measurements. Impairment of cardiac and pulmonary function was measured intraoperatively, but this was compensated by therapy, so that oxygen delivery was maintained. Nonetheless, there was a decrease in oxygen consumption intraoperatively due to decreased oxygen extraction. Postoperatively, there was an increase in cardiac output, oxygen delivery and oxygen consumption. It is postulated that the fall in oxygen consumption intraoperatively may result in a metabolic debt and that a hyperdynamic postoperative state represents the physiologic response necessary to repair the damage caused intraoperatively by relative cellular hypoxia.

Cardiac Output↗

Effects of remifentanil and fentanyl on intraocular pressure during the maintenance and recovery of anaesthesia in patients undergoing non-ophthalmic surgery.

BACKGROUND AND OBJECTIVE: To compare the effects of remifentanil and fentanyl on intraocular pressure during the maintenance and recovery of anaesthesia in patients undergoing elective non-ophthalmic surgery. METHODS: Thirty-two patients (ASA I-II) were randomized into two groups to receive either a continuous infusion of remifentanil (0.25-0.5 microg kg(-1) min(-1), n =16, Group R) or an intermittent bolus of fentanyl (2-5 microg kg(-1), n = 16, Group F) during the maintenance of anaesthesia. For the induction of anaesthesia, Group R received remifentanil 1 microg kg(-1) and Group F received fentanyl 2 microg kg(-1); both groups then received propofol 2 mg kg(-1) with vecuronium 0.1 mg kg(-1). Anaesthesia in both groups was maintained with a continuous infusion of propofol 4-8 mg kg(-1) h(-1). Ventilation of the lungs was controlled to a constant end-tidal PCO2 of 4.7-5.4 kPa. Blood pressure, electrocardiography, heart rate and oxygen saturation were monitored throughout anaesthesia. Intraocular pressure was determined before surgery, during the maintenance of anaesthesia, 2 min after emergence and in the recovery room using a Perkins hand-held applanation tonometer by an ophthalmologist blinded to the anaesthetic technique. RESULTS: After induction of anaesthesia, a significant decrease in intraocular pressure in the remifentanil group from 13.6 +/- 2.6 to 7.1 +/- 3.1 mmHg (P < 0.001) and in the fentanyl group from 13.7 +/- 2.2 to 9.7 +/- 3.4 mmHg (P < 0.001) was observed and maintained during anaesthesia. Thirty minutes after the end of anaesthesia, intraocular pressure returned to baseline values in both groups (remifentanil: 13.9 +/- 2.8 mmHg, P = 0.28; fentanyl: 13.6 +/- 2.3 mmHg, P = 0.59). The intraocular pressure and haemodynamic variables did not differ significantly between the two groups (intraocular pressure, P = 0.7327; blood pressure, P = 0.1295; heart rate, P = 0.8601). CONCLUSIONS: Remifentanil maintains intraocular pressure at an equally reduced level compared with fentanyl.

Adolescent↗

No effect of cardiopulmonary bypass on hypnosis in patients anaesthetized with propofol and alfentanil.

BACKGROUND: The effect of cardiopulmonary bypass (CPB) on the level of anaesthetic depth has not been studied previously in a randomized way. METHODS: We assessed the effect of CPB on the propofol needed to maintain a fixed bispectral index score, and on the recovery from anaesthesia in 22 patients undergoing coronary artery bypass graft surgery with CPB (on-pump) compared with 18 patients operated on without CPB (off-pump). Anaesthesia was induced and maintained with propofol and alfentanil. Throughout the procedure, the infusion rate of propofol was adjusted to keep the BIS value at 40 +/- 5. RESULTS: With the off-pump technique, the duration of surgery and anaesthetic administration were significantly greater. The need for propofol in proportion to time was exactly the same in both groups. During anaesthesia and the first 3 h thereafter, the BIS recordings were similar in both groups. No differences were detected in the time to awakening or tracheal extubation. CONCLUSIONS: CPB does not affect propofol requirements or immediate postoperative recovery compared with the off-pump technique.

Aged↗

A comparison of mivacurium dosage requirements during isoflurane and desflurane anesthesia.

STUDY OBJECTIVE: To evaluate the dose requirement and recovery characteristics of mivacurium infusions during anesthesia with equipotent concentrations of either desflurane or isoflurane. DESIGN: Randomized, open-study comparing the effects of desflurane and isoflurane on mivacurium-induced neuromuscular blockade. SETTING: Operating suite of a university-affiliated medical center. PATIENTS: 41 ASA status I, II, and III adult patients, requiring more than 45 minutes of neuromuscular blockade for surgery. INTERVENTIONS: Following a standardized induction sequence and established steady desflurane-nitrous oxide (DES group) or isoflurane-nitrous oxide (ISO group) anesthesia at 1 minimum alveolar concentration (MAC), an intubating dose of 0.2 mg/kg of mivacurium chloride was administered. Ventilation was maintained with a face mask until the first twitch (T1) of the evoked train-of-four (TOF) reached 10% or less of control when tracheal intubation was performed. T1 was allowed to return to 10% of its control value. An infusion of mivacurium at the initial rate of 5 micrograms/kg/min was then started and adjusted to maintain T1 at 10% +/- 2% of control. Within 20 minutes of completion of surgery, the mivacurium infusion was stopped, and the time for the evoked electromyograph (EMG) to return to 25% and 75% of the original baseline was noted. MEASUREMENTS AND MAIN RESULTS: Neuromuscular function was monitored continuously by an evoked EMG. The average infusion rate was 5.7 +/- 2.4 micrograms/kg/min (mean +/- SD) for DES group (n = 20) and 6.6 +/- 2.7 micrograms/kg/min for ISO group (n = 21) (p = NS). There was no change in the infusion rate of mivacurium over time for both groups. However, there was an inverse relationship in both groups between the time to recovery following a bolus dose and the subsequent mean infusion rate of mivacurium (correlation coefficient = -5.0; p < 0.005). The spontaneous recovery index (T25-75) for the two groups was identical, 11.5 +/- 4.9 min (mean +/- SD) for DES group and 11.5 +/- 7.9 min for ISO group (p = NS). CONCLUSION: There were no differences in the dose requirement and recovery indices of mivacurium during either desflurane or isoflurane-based anesthesia. Patients who took longer to recover from the bolus dose in both groups showed a subsequent reduction in dose requirements of mivacurium.

Adult↗

Noninvasive measurement of cardiac output by continuous-wave Doppler echocardiography: initial experience and review of the literature.

Doppler echocardiographic measurement of the velocity of blood flow in the ascending aorta is a noninvasive method for determining cardiac output in the critically ill patient. Fifty-four patients in the medical intensive care unit (35 men and 19 women, age range 41 to 91 years) in whom a Swan-Ganz catheter had been inserted underwent measurement of cardiac output with use of a commercially available continuous-wave Doppler echocardiographic instrument. The aortic root diameter was measured by A-mode echocardiography. An additional 26 patients (17 men and 9 women, age range 20 to 83 years) who had undergone an open-heart surgical procedure and had hemodynamic monitoring in the postoperative period also underwent Doppler measurement of cardiac output. In these patients, the aortic root diameter was measured directly intraoperatively. Cardiac output was also determined by thermodilution in both groups. An adequate A-mode study was possible in 83% of the medical patients but only 27% of the surgical patients. Doppler signals were adequate in 84% of the medical patients and 92% of the surgical patients. The correlation between thermodilution and Doppler-derived cardiac output was good in both the medical (r = 0.94, SEE = 0.78, P less than 0.001) and the surgical (r = 0.85, SEE = 0.78, P less than 0.001) group. Doppler echocardiography is a promising noninvasive method for determining cardiac output in critically ill patients.

Adult↗