Intraoperative modulation of alveolar macrophage function during isoflurane and propofol anesthesia

BACKGROUND: Alveolar macrophages are a critical part of the defense against pulmonary infection. Thus the authors determined time-dependent changes in alveolar macrophage functions in patients having surgery who were anesthetized with isoflurane or propofol. METHODS: Patients anesthetized with propofol (n = 30) or isoflurane (n = 30) during orthopedic surgery were studied. Alveolar macrophages were harvested by bronchoalveolar lavage immediately, and 2, 4, and 6 h after induction anesthesia and at the end of surgery. The fraction of aggregated and nonviable macrophages was determined. Then phagocytosis was measured by ingestion of opsonized and unopsonized particles. Finally, microbicidal activity was determined as the ability of the macrophages to kill Listeria monocytogenes directly. RESULTS: Demographic and morphometric characteristics of the patients given propofol and isoflurane were similar, as were their levels of pulmonary function and hemodynamic responses. The fraction of alveolar macrophages ingesting opsonized and unopsonized particles, and the number of particles ingested, decreased significantly over time, with the decrease slightly but significantly greater during isoflurane anesthesia. Microbicidal function decreased progressively during anesthesia and surgery, with the decrease almost twice as great during isoflurane compared with propofol anesthesia. The fraction of aggregated macrophages and recovered neutrophils increased over time in the patients given each anesthetic. CONCLUSIONS: Pulmonary immunologic function changed progressively during anesthesia and surgery. The data from this study suggest that pulmonary defenses are modulated by the type of anesthesia and by the duration of anesthesia and surgery.     

Circulatory changes at the time of anesthetic induction and endotracheal intubation--comparison of thiamylal induction group and propofol induction group

We examined the circulatory changes after intravenous thiamylal with additional injection of thiamylal 1 minute before intubation and after propofol at the time of anesthetic induction and endotracheal intubation. Sixty ASA I or II patients were studied after the institutional and informed consents. We compared the following three groups. Group I (n = 20): Anesthesia was induced with thiamylal 5 mg.kg-1 and intubation with the aid of vecuronium 0.1 mg.kg-1. Group II (n = 20): Anesthesia was induced with thiamylal 3 mg.kg-1 and vecuronium 0.1 mg.kg-1. One minute before the intubation, the patients received additional thiamylal 4 mg.kg-1. Group III (n = 20): Anesthesia was induced with propofol 2.5 mg.kg-1 and intubation was performed with the aid of vecuronium 0.1 mg.kg-1. We examined the systolic, diastolic and mean blood pressures, heart rate, and rate pressure product (RPP) in the three groups. The examinations were performed before and after induction, soon after intubation, and every one minute after intubation for 5 minutes. After the endotracheal intubation, the systolic blood pressure and heart rate increased in Group I. But the systolic and diastolic pressures were significantly more stable in Group II and Group III. The change of the RPP was slight and most stable in Group II compared with the other two groups. We conclude that additional injection of thiamylal 4 mg.kg-1 following induction of anesthesia with thyamylal 3 mg.kg-1 1 minute before endotracheal intubation is an effective method for minimizing the increase in blood pressure and circulatory changes at the time of rapid induction of anesthesia and endotracheal intubation.     

Incremental bolus versus a continuous infusion of propofol for deep sedation/general anesthesia during dentoalveolar surgery

PURPOSE: This article compared the use of the traditional incremental bolus technique with the continuous infusion technique for the administration of propofol for deep sedation/general anesthesia. PATIENTS AND METHODS: Patients were sedated with midazolam and fentanyl and then had maintenance of an anesthetic state achieved with propofol administered by either of the two techniques. Data were collected to evaluate the overall surgical/anesthetic procedure, movement of the patient, and his or her hemodynamic status. RESULTS: Both groups received a mean maintenance dose of propofol exceeding 6 mg/kg/hr. However, the patients in the continuous infusion group received a statistically greater maintenance dose (continuous infusion + supplemental vs incremental bolus). All patients were maintained in a deep sedation/general anesthetic state. Respiratory and blood pressure values were comparable in both groups. However, the continuous infusion group showed improved hemodynamic stability manifested as fewer fluctuations in heart rate. Visual analog scale (VAS) questionnaires completed by the surgeon and surgical assistant reported less patient movement and improved surgical/anesthetic conditions with the continuous infusion technique. Recovery of the two groups was comparable. CONCLUSION: This study, although finding advantages in the continuous infusion technique, showed satisfactory conditions associated with both techniques.     

Electromotive drug administration of lidocaine as an alternative anesthesia for transurethral surgery

PURPOSE: A multicenter study was undertaken to evaluate the safety, efficacy and cost of electromotive drug administration of intravesical lidocaine to produce bladder local anesthesia as an alternative to traditional methods of spinal or general anesthesia. MATERIALS AND METHODS: A total of 94 patients were enrolled in the study who had either a history of bladder tumor that required cold cup bladder biopsy with fulguration for possible recurrence as a comparison trial, a bladder tumor treated with transurethral resection/fulguration or benign prostatic hyperplasia/carcinoma treated with transurethral resection. Pain scores using a Verbal Rating Scale were recorded for each individual biopsy, fulguration and resection event. Data for direct and indirect costs were collected using a standardized form for each patient to capture the details of the procedure, including times, drugs and disposables for each patient. RESULTS: There was a significant reduction in pain for patients who received electromotive intravesical lidocaine compared to no anesthesia for biopsy (p<0.03). Similarly, electromotive intravesical lidocaine for bladder biopsy and transurethral bladder tumor resection/fulguration was associated with higher patient satisfaction compared to previous treatments (p<0.00002). In contrast, electromotive intravesical lidocaine was insufficient for 3 of 6 transurethral prostatic resections. The cost per patient was about $146 Cdn less with electromotive intravesical lidocaine than with conventional general/spinal anesthesia. CONCLUSIONS: Electromotive intravesical lidocaine may be a safe, effective and affordable form of anesthesia for the ambulatory care of patients requiring transurethral bladder biopsy, resection or fulguration with a potential for cost savings.     

Autoregulation of human inner ear blood flow during middle ear surgery with propofol or isoflurane anesthesia during controlled hypotension

We used controlled hypotension to obtain a bloodless cavity during middle ear surgery under an optical microscope. No previous study has assessed the effect of controlled hypotension on inner ear blood flow (IEF) autoregulation in humans receiving propofol or isoflurane anesthesia. In the present study, the IEF autoregulation was determined using laser Doppler flowmetry in combination with transient evoked otoacoustic emissions (TEOAEs) during controlled hypotension with sodium nitroprusside in 20 patients randomly anesthetized with propofol or isoflurane. A coefficient of IEF autoregulation (Ga) was determined during controlled hypotension, with a Ga value ranging between 0 (no autoregulation) and 1 (perfect autoregulation). During controlled hypotension with propofol, IEF remained stable (1%+/-6%; P > 0.05) but decreased by 25%+/-8% with isoflurane (P < 0.05). The Ga was higher during propofol anesthesia (0.62+/-0.03) than during isoflurane anesthesia (0.22+/-0.03; P < 0.0001). Under propofol anesthesia, there were individual relationships between TEOAE amplitude and change in IEF in four patients. Such a correlation was not observed under isoflurane anesthesia. These results suggest that human IEF is autoregulated in response to decreased systemic pressure. Furthermore, isoflurane has a greater propensity to decrease cochlear autoregulation and function than propofol. IMPLICATIONS: The present study shows that inner ear blood flow is autoregulated under propofol, but not isoflurane, anesthesia during controlled hypotension in humans during middle ear surgery. Further studies are needed to explore the postoperative auditory functional consequences of the choice of the anesthetic drug used in middle ear surgery.     

The impact of long-term hemodialysis on pituitary-adrenocortical function

The activity of the hypothalamic-pituitary-adrenal axis in hemodialyzed (HD) patients has been investigated, with conflicting results. Different results are reported concerning both basal ACTH and cortisol concentration and the responses to different stimulating agents, in chronic hemodialyzed patients. The present study was performed in order to asses whether the length of the hemodialytic treatment may affect the pituitary and adrenocortical response to stimulation with ovine CRH (oCRH) and with exogenous ACTH in a group of patients on chronic HD for more than 10 years. Ten uremic patients (aged 38-71, 6 males and 4 females) on chronic hemodialysis for at least 10 years and 7 healthy subjects matched for age and sex were studied. The patients were tested on the day preceding dialysis session. Each subject received on different non-consecutive days oCRH (100 micrograms i.v. in bolus) and ACTH (Synacthen 0.25 mg i.v. in bolus), and blood samples were obtained at appropriate intervals. Basal ACTH and cortisol levels of HD patients were in the upper limit of normal range (ACTH 39.21 +/- 11.11 pg/mL in HD patients vs. 26.88 +/- 14.12 pg/mL in controls; cortisol 19.96 +/- 5.07 in HD patients vs. 12.66 +/- 4.44 in controls); however, the means were not significantly different compared with controls. Following oCRH administration a net increase of ACTH and cortisol was observed in every patient tested (ACTH peak 83.81 +/- 28.49 in HD vs. 78.73 +/- 22.87 pg/mL in controls; cortisol peak 30.73 +/- 19.31 in HD vs. 20.05 +/- 3.19 micrograms/dL in controls).(ABSTRACT TRUNCATED AT 250 WORDS)     

Upper airway reflexes during a combination of propofol and fentanyl anesthesia

BACKGROUND: The effects of intravenous anesthetics on airway protective reflexes have not been fully explored. The purpose of the present study was to characterize respiratory and laryngeal responses to laryngeal irritation during increasing doses of fentanyl under propofol anesthesia. METHODS: Twenty-two female patients anesthetized with propofol and breathing through the laryngeal mask airway were randomly allocated to three groups: (1) eight patients who received cumulative total doses of 200 microg fentanyl given in the form of two doses of 50 microg and one dose of 100 microg spaced 6 min under mechanical controlled ventilation while end-tidal carbon dioxide tension (PCO2) was maintained at 38 mmHg (fentanyl-controlled ventilation group), (2) eight patients who received cumulative total doses of 200 microg fentanyl while breathing spontaneously while end-tidal PCO2 was allowed to increase spontaneously (fentanyl-spontaneous ventilation group), and (3) six spontaneously breathing patients who were anesthetized with propofol alone (propofol group). The laryngeal mucosa of each patient was stimulated by spraying the cord with distilled water, and the evoked responses were assessed by analyzing the respiratory variables and endoscopic images. RESULTS: Before administration of fentanyl, laryngeal stimulation caused vigorous reflex responses, such as expiration reflex spasmodic panting, cough reflex, and apnea with laryngospasm. Increasing doses of fentanyl reduced the incidences of all these responses, except for apnea with laryngospasm, in a dose-related manner in both the fentanyl-controlled ventilation and the fentanyl-spontaneous ventilation groups. Detailed analysis of endoscopic images revealed several characteristics of laryngeal behavior during the airway reflex responses. CONCLUSION: Incremental doses of fentanyl depress airway reflex responses in a dose-related manner, except for apnea with laryngospasm.     

Pharyngeal flap necrosis as a cause of airway obstruction during induction of anesthesia

Anesthesiologists should approach the airway carefully in the patient with a diagnosis of head and neck carcinoma, particularly if the patient has had previous surgery and reconstruction. Patients with head and neck carcinoma may be difficult intubations due to altered anatomy from the tumor or fibrotic changes because of radiation therapy. Our patient had had pharyngectomy and reconstruction with a pectoralis major skin flap. The patient returned to the operating suite for wide-excision pharyngectomy and had acute airway obstruction after induction of general anesthesia. The pectoralis flap had necrosed, pulling away from the pharyngeal wall and obstructing the patient's glottic opening.     

Althesin (alphadione, CT 1341) a 'new' induction agent for anesthesia

Althesin (alphadione) is a hypnotic agent introduced in the U.K. a few years ago by the firm of Glaxo. It is mixture of two steroids: alphaxalone 9 mg per ml and alphadolone 3 mg per ml, in solution in cremophore EL. After a concise review of the history of steroid anesthetics, the pharmacology of the new product is described. In a personal investigation, Althesin was used to induce anesthesia in 100 patients. The dose equivalent with thiopentone was determined first. It was found to amount to 52 microliter per kg corresponding to 3 mg per kg of thiopentone. A separate form was completed for each individual patient, to record the side effects, if any. The pulse and blood pressure were checked once a minute after the induction (for 5 minutes). In 8 patients the following parameters were recorded: plethysmogram, ECG, central venous pressure, pulse rhythm arterial pressure, stroke volume and cardiac output. Compared with thiopentone, Althesin is not significantly worse, but neither does it present any advantages where the circulatory parameters determined are concerned. In view of this and the recent publication concerning hypersensitivity reactions, we have ceased to use this hypnotic agent in our department.     

Metabolic changes during recovery in normothermic versus hypothermic patients undergoing surgery and receiving general anesthesia and epidural local anesthetic agents

BACKGROUND: Mild hypothermia is accompanied by metabolic changes. Epidural local anesthetic agents attenuate the surgical stress response, but it is not known whether they modulate thermal stress. METHODS: Thirty patients undergoing colorectal surgery, performed by one surgical team, received epidural 0.5% bupivacaine to achieve T3-S5 sensory block. They were then assigned randomly to two groups of 15 patients each. The control or unwarmed group was left to cool during surgery, whereas active warming was used in the warmed group. General anesthesia was induced by thiopentone, vecuronium, fentanyl, nitrous oxide in oxygen, and enflurane. At the end of surgery, both groups received epidural 0.25% bupivacaine to maintain a T5-L3 sensory block. Aural canal (core) and skin surface (15 sites) temperatures; oxygen consumption; pain visual analogue score; and concentrations of epinephrine, norepinephrine, glucose, cortisol, lactate, and free fatty acids in plasma were measured before epidural blockade, 30 min after epidural blockade, at the end of surgery, and for 4 h after surgery. Patients and those measuring the outcomes were unaware of group allocation. RESULTS: Core and mean skin temperatures decreased significantly in the control group (P < 0.001) but not in the warmed group. Catecholamine concentrations in plasma decreased significantly after epidural block, and although concentration of epinephrine in plasma increased from baseline sharply in the control group at the end of surgery (P = 0.004), it decreased in the warmed group (P = 0.007). During recovery, there was no difference between the two groups for norepinephrine concentrations in plasma, body weight-adjusted oxygen consumption, pain visual analogue score, and metabolites. CONCLUSIONS: The postoperative metabolic changes obtained with epidural block were similar except for an attenuated concentration of epinephrine in normothermic patients compared with those who were mildly hypothermic.     

EMLA prevents pain during local anesthesia for cataract surgery

We developed a method to identify maternal deaths (deaths to women within 365 days of delivery) by linking Tennessee vital records. A computerized algorithm compared personal identifiers from the death certificates of reproductive-aged women to maternal identifiers on birth and fetal death certificates. For each decedent record which met the study criteria, the algorithm calculated a "match score" by comparing common elements in both files. The algorithm awarded full credit for data elements that agree exactly, partial credit for elements in partial agreement, and subtracted credit for information that mismatched. Match scores ranged from 0 to 35 for the 9,009 deaths in women 10-55 years of age during the three study years, with the majority of scores (96.3%) being 0 for "no match." Match scores of 1 to 8 were obtained by 153 (1.7%) of decedent records, while scores greater than 9 were obtained by 184 (2.0%) of decedent records. We used nurse-abstracted hospital, autopsy, and coroner records as our standard to verify the linkages. Manual review of personal identifiers showed that scores of 12 or less were not a match while scores of 13 or more indicated "true" matches. Based on this cutoff, the linkage algorithm yielded 130 maternal deaths. Of these, 32 (25%) were classified as truly pregnancy-related upon medical record review by an obstetrician. The remaining 98 deaths were associated only temporally with pregnancy. During the same time period, 16 individuals were identified to the State Health Department on their death certificates as dying from pregnancy-related causes, including one not identified by the linkage process.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effect of anesthetic technique on cardiac morbidity following carotid artery surgery

Clarithromycin and rifabutin are among the most promising drugs for the therapy of infections caused by Mycobacterium avium or other atypical mycobacteria. Since synergism of combined drugs is important in order to achieve strong antimycobacterial activity, the combined inhibitory effects of antibacterial agents should also be investigated when agents are evaluated for possible use in antimycobacterial drug therapy. In the present study we examined the antimycobacterial activity of clarithromycin, rifabutin, and their combination against 51 clinical isolates of the M. avium complex from patients with acquired immune deficiency syndrome (AIDS) with disseminated mycobacteriosis. A concentration-dependent inhibition was seen for each drug. The antibacterial effect was significantly more pronounced for the combined drugs than for the agents tested separately. Synergism, against up to 88% of the strains tested, was seen for the tested drugs combined at different concentrations. All 51 M. avium strains were susceptible to the combination of 4 mg/l clarithromycin and 2 mg/l rifabutin.     

Cardiopulmonary and anesthetic effects of propofol in wild turkeys

OBJECTIVE: To determine safety, anesthetic variables, and cardiopulmonary effects of i.v. infusion of propofol for induction and maintenance of anesthesia in wild turkeys. ANIMALS: 10 healthy, adult wild turkeys. PROCEDURE: Anesthesia was induced by i.v. administration of propofol (5 mg/kg of body weight) over 20 seconds and was maintained for 30 minutes by constant i.v. infusion of propofol at a rate of 0.5 mg/kg/min. Heart and respiratory rates, arterial blood pressures, and arterial blood gas tensions were obtained prior to propofol administration (baseline values) and again at 1, 2, 3, 4, 5, 10, 15, 20, 25, and 30 minutes after induction of anesthesia. All birds were intubated immediately after induction of anesthesia, and end-tidal CO2 concentration was determined at the same time intervals. Supplemental oxygen was not provided. RESULTS: Apnea was observed for 10 to 30 seconds after propofol administration, which induced a decrease in heart rate; however, the changes were not significant. Compared with baseline values, respiratory rate was significantly decreased at 4 minutes after administration of propofol and thereafter. Systolic, mean, and diastolic pressures decreased over the infusion period, but the changes were not significant. Mean arterial blood pressure decreased by 30% after 15 minutes of anesthesia; end-tidal CO2 concentration increased from baseline values after 30 minutes; PO2 was significantly decreased at 5 minutes after induction and thereafter; PCO2 was significantly (P < 0.05) increased after 15 minutes of anesthesia; and arterial oxygen saturation was significantly (P < 0.05) decreased at the end of anesthesia. Two male turkeys developed severe transient hypoxemia, 1 at 5 and the other at 15 minutes after induction. Time to standing after discontinuation of propofol infusion was 11 +/- 6 minutes. Recovery was smooth and unremarkable. CONCLUSION: Propofol is an effective agent for i.v. induction and maintenance of anesthesia in wild turkeys, and is useful for short procedures or where the use of inhalational agents is contraindicated.     

Anesthesia induction for laryngeal mask insertion--comparison of propofol with midazolam and propofol with thiopental

STUDY DESIGN: Radiographs and charts of 61 patients sustaining cervical spine trauma were studied prospectively to determine the incidence of vertebral artery injuries and possible correlative factors. Statistical analysis was conducted using chi-square testing of a two-way classification system. OBJECTIVES: To elucidate the incidence of vertebral artery injuries associated with cervical spine trauma, and to determine the value of various factors in predicting the existence of a vertebral artery injury. SUMMARY OF BACKGROUND DATA: During a 7-month period, 61 patients (41 male patients, 20 female; average age, 40.3 years) with cervical spine trauma were studied. METHODS: All patients admitted to the authors' hospital with cervical spine injuries underwent magnetic resonance imaging and magnetic resonance angiography of their cervical spine. All magnetic resonance angiographies were examined for vertebral artery injury. Data on demographics and the injury were recorded. RESULTS: Complete disruption of blood flow through the vertebral artery was demonstrated by magnetic resonance angiography in 12 of the 61 patients (19.7%). Ten of the 12 patients (83%) had either flexion distraction or flexion compression injuries. Age, sex, mechanism of injury, neurologic impairment, and associated injuries were not statistically significant in predicting the presence of a vertebral vessel occlusion. CONCLUSION: The findings in this study may support the need for vertebral vessel evaluation in selective patients, particularly those with flexion injuries and with neurologic symptoms consistent with vertebral artery insufficiency syndrome that do not correlate with the presenting bone and soft-tissue injuries.     

Effect of propofol infusion on the endocrine response to cardiac surgery

PURPOSE: Bilateral lower extremity venous duplex scanning for acute deep venous thrombosis (DVT) has been advocated because of the high incidence of occult contralateral leg involvement. We investigated the clinical necessity of such a policy. METHODS: The results from 2996 venous duplex studies performed during the past 2 years were retrospectively reviewed. A total of 1694 of these scans were performed on patients with symptoms, of whom 248 (15%) were found to have an acute DVT. Symptoms were limited to one side in 198 patients, whereas bilateral complaints were noted in 50 patients. RESULTS: Among the patients with symptoms of acute DVT, 72 (29%) had bilateral involvement. Bilaterality was more likely in patients with bilateral symptoms than in those with only unilateral symptoms (56% vs 22%; p < 0.005). Of the patients with unilateral symptoms and bilateral DVT, all of them had either acute (80%) or acute and chronic (20%) thrombosis in the symptomatic leg. The contralateral asymptomatic limb had fewer acute and more chronic DVT (41% and 55%, respectively). No patient from the entire group admitted with symptoms had an acute DVT in the asymptomatic limb without a concomitant acute DVT in the symptomatic leg. Unilateral scanning would decrease the examination time by 21% and potentially increase total reimbursement for symptomatic venous scans by 9% compared with routine bilateral duplex scanning. CONCLUSIONS: Although bilateral involvement is frequent in patients with symptoms of acute DVT, treatment in these patients is not altered by this finding. We conclude that contralateral venous scanning in patients with unilateral symptoms is not clinically indicated and that unilateral scanning would result in improved cost-efficiency for vascular laboratories.     

Cardiorespiratory and anesthetic effects of propofol and thiopental in dogs

OBJECTIVE: To compare cardiorespiratory and anesthesia effects of IV administered propofol and thiopental in dogs. ANIMALS: 6 healthy mixed-breed dogs. PROCEDURE: Each dog was anesthetized with isoflurane, then a thermistor catheter was inserted in the pulmonary artery. After a minimum of 2.5 hours of recovery, a catheter was placed in a cephalic vein for administration of lactated Ringer's solution and drugs. Propofol (8 mg/kg of body weight) or thiopental (19.4 mg/kg) was administered to each dog in a randomized crossover design study. All dogs were intubated and allowed to breathe 100% oxygen spontaneously. Heart rate and rhythm; systolic, diastolic, and mean arterial blood pressures; respiratory rate; end-tidal carbon dioxide concentration; tidal volume; and reflexes (toe web pinch, palpebral response, and jaw tone) were measured before and every 2 minutes for the first 10 minutes, then at 15, 30, and 60 minutes after drug administration. Cardiac output was determined at 0, 2, 6, 10, 15, 30, and 60 minutes, and blood samples were collected at 0, 2, 10, and 30 minutes. Time to endotracheal extubation, head lift, and ability to sit sternally and walk unaided were recorded. RESULTS: 3 of 6 dogs in each group were apneic after drug administration. Reflexes were decreased similarly for both anesthetic agents, but were not completely lost. Time to sternal position and walking unaided were significantly shorter in response to propofol. CONCLUSION: Anesthesia was rapid; however, respiratory depression and apnea were major adverse effects associated with propofol and thiopental. Propofol has the advantage of inducing rapid, coordinated anesthesia recovery.     

Effect of remifentanil on clinical and electroencephalographic parameters of depth of anesthesia in balanced anesthesia with propofol, enflurane or isoflurane

Electrophysiological parameters are well-suited to detect changes in cerebral function. The present study investigates whether balanced anaesthesia with remifentanil during nociceptive stimulation is associated with changes in clinical and electrophysiological parameters indicating inadequate depth of anaesthesia. Following IRB approval and written informed consent, 23 patients (ASA: I; age: 36 +/- 11) scheduled for elective gynaecological laparoscopy were included in the study. Without any premedication, anaesthesia was induced with remifentanil (1.0 microgram/kg bolus injection), propofol (0.5 mg/kg added by repetitive (10 mg) bolus injections every 10 s until unconciousness) and vecuronium (0.1 mg/kg). Following endotracheal intubation (normoventilation: PetCO2: 36 bis 38 mmHg), remifentanil infusion was started with continuous doses of 0.5 microgram/kg/min over 5 minutes and maintained with 0.25 microgram/kg/min during surgery. Remifentanil was randomly combined with propofol (group 1: 100 micrograms/kg/min; n = 7), enflurane (group 2: 0.5 MAC; n = 8) or isoflurane (group 3: 0.5 MAC; n = 8). Monitoring included: heart rate (beats/min), mean arterial pressure (mmHg), oxygen saturation (%), endtidal CO2 (mmHg) and endtidal enflurane and isoflurane (%). EEG: 2-channel recordings of Fz versus mastoid and ECG (artefact control) during steady-state anaesthesia and surgery. Following fast-fourier-transformation (4 s; 256/s; 0.5 to 35.0 Hz), spectral power densities were calculated for the selected frequency bands. Auditory evoked potentials (AEP; middle latency) were registered simultaneously after binaural stimulation via head-phones click-stimulation (6 Hz; 75 dB above hearing threshold; 512 stimulations per average). Bandpass was 0.01 to 2.0 kHz. Analysis: Na, Pa, Nb (latencies; ms) and peak-to-peak amplitudes (NaPa, PaNb; microV). EEG and AEP recording technique [15]. The study protocol included baseline values from pre-intubation, pre-surgery, the respective post-stimulation values (1 min, 3 min, 5 min) and all data at five-minute intervals during surgery until emergence from anaesthesia. During steady-state study conditions with defined remifentanil applications, mean data indicate that in response to nociceptive stimuli no changes in clinical or electrophysiological parameters were observed. In contrast to other studies using different anaesthetic techniques, the present data from remifentanil indicate very stable haemodynamic and electrophysiological parameters (EEG, AEP) during noxious stimulations. Adjustable and with no plasma accumulation, remifentanil demonstrates potent antinociceptive effects resulting in signs of adequate anaesthesia.     

Comparison of eltanolone and propofol in anesthesia for termination of pregnancy

A randomized study was designed to compare eltanolone (pregnanolone) and propofol anesthesia in 60 unpremedicated women undergoing outpatient termination of pregnancy. The initial doses for induction of anesthesia were 0.8 mg/kg for eltanolone and 2 mg/kg for propofol followed by an additional 25% increment if necessary. The doses required for successful induction were 0.82 +/- 0.06 and 2.1 +/- 0.3 (mean +/- SD) mg/kg for eltanolone and propofol, respectively. Discomfort or pain on injection occurred in none of the patients given eltanolone and in 20% of those receiving propofol (P < 0.05). To maintain satisfactory anesthesia, 29% of the patients given eltanolone and 70% of the patients given propofol needed extra bolus doses of the study drug (P < 0.01). Excitation (twitching of extremities or slight hypertonus) occurred in 29% of the patients in the eltanolone group compared to none in the propofol group (P < 0.05). Both clinical (opening eyes, orientation, walking, tolerating oral fluids, voiding) and psychomotor recovery (Maddox Wing test and Digit Symbol Substitution test) returned to baseline more slowly after eltanolone than after propofol. Overall home readiness was achieved later in the eltanolone group [median 57 min (range 41-190 min)] compared to the propofol [37 (32-100 min)] group. We conclude that recovery from anesthesia is more rapid from propofol as compared to eltanolone anesthesia.