Admixture of propofol and alfentanil. Use for intravenous sedation and analgesia during transvaginal oocyte retrieval

The effect of anesthetic agents for oocyte pick-up on in vitro fertilization outcome: A retrospective study in a tertiary center

OBJECTIVE

General anesthesia is used in most in vitro fertilization (IVF) clinics for oocyte pick-up (OPU), however, there is no consensus on type of anesthetic agent use among clinicians performing OPU. Therefore, we aimed to evaluate the effects of propofol, ketamine, or combination of propofol and ketamine (P + K) for OPU on IVF outcome.

MATERIAL AND METHODS

Three hundred and thirty three women (n = 333) undergoing IVF treatment were retrospectively included and were evaluated in three groups depending on whether they received propofol (n = 217), or ketamine (n = 60), or P + K (n = 56) for anesthesia during OPU.

RESULTS

Baseline characteristics and duration of anesthesia of each group were comparable except lower motile sperm percentage in the ketamine group compared to the propofol group (p = 0.002). Fertilization rate (FR) was decreased with ketamine compared to propofol (p = 0.013) and P + K (p = 0.008). After adjustment for sperm motility, this negative effect of ketamine on FR persisted. Implantation, clinical pregnancy, take-home baby rates, and oocyte retrieval parameters (number of total retrieved oocyte, metaphase II oocytes, embryo and methaphase II rate, and embryo quality) did not differ between the groups. Extended anesthesia duration (>30 min) was associated with low implantation (p = 0.04) and clinical pregnancy rates (p = 0.02).

CONCLUSION

Ketamine use during OPU can affect FR compared to propofol and P + K. Long durations of anesthesia also seem to decrease implantation and clinical pregnancy rates.

Sedation and analgesia for transvaginal oocyte retrieval: an audit resulting in a change of clinical practice

The aim was to audit the standard of care at oocyte retrieval with respect to the analgesia used. Before June 1999, a combination of intramuscular pethidine and prochlorperazine was given as a single dose. Many women found this to be unsatisfactory and requested general anaesthesia for subsequent oocyte retrievals. An intravenous sedation and analgesia regimen was introduced using a combination of midazolam and fentanyl. The introduction of this regimen was audited and compared with the established regimen. This study describes the experience with this technique, its patient acceptability, safety and cost implications.

Comparison of a Bolus of Fentanyl With an Infusion of Alfentanil During Target-Controlled Propofol Infusion in Third Molar Extraction Under Conscious Sedation

PURPOSE

This study was designed to compare hemodynamic changes, respiratory depression, and patient satisfaction between a bolus of fentanyl and an infusion of alfentanil during target-controlled propofol infusion in third molar extraction under conscious sedation.

PATIENTS AND METHODS

Forty patients were randomly assigned to receive either a bolus of fentanyl (n = 24) or an infusion of alfentanil (n = 16) in combination with target-controlled propofol infusion. Hemodynamic changes, respiratory depression, sedation, and cooperation scores were recorded during surgery and patient satisfaction scores were assessed after surgery.

RESULTS

Changes in mean blood pressure, heart rate, or oxygen saturation within and between the groups were not significant throughout the procedure. There were no significant differences in sedation, cooperation, and patient satisfaction scores between the 2 groups.

CONCLUSION

Because there was no difference in hemodynamic variables and patient satisfaction scores between a bolus of fentanyl and an infusion of alfentanil during target-controlled propofol infusion, both combinations are suitable for conscious sedation in third molar extraction.

The pain-relieving effect of electro-acupuncture and conventional medical analgesic methods during oocyte retrieval: a systematic review of randomized controlled trials

OBJECTIVE

The primary objective of the present review was to determine what pain-relieving effect had been reported for acupuncture and other conscious sedation methods in assisted reproduction therapy since 1990. The secondary objective was to determine pregnancy rates, when possible.

METHODS

The data source was the Medline database of the National Library of Medicine covering the period January 1990-January 2004. Bibliographies of relevant publications and review articles were scanned. A systematic review and meta-analyses of randomized, controlled trials comparing the pain-relieving effect of acupuncture and other conscious sedation methods was carried out.

RESULTS

Of the 30 trials identified, 12 met the selection criteria for this systematic review and were included in the analysis. Five of the 12 studies reported differences in pain experiences during oocyte aspiration, but it was only possible to group the three trials evaluating the effect of electro-acupuncture (EA). The outcomes of these three studies were homogenous except from maximal and average pain.

CONCLUSION

No method could be regarded as being superior to another, and no consensus on which method is optimal for pain relief during oocyte retrieval was found. Low doses of lignocaine can, however, be recommended in paracervical block (PCB) as well as EA without pre-medication. The clinical pregnancy rates appeared to be similar between the studies. Since pain experience varies from individual to individual, the optimal method of conscious sedation may also be individualized.

Physicochemical Compatibility of Propofol-Lidocaine Mixture

To examine the physicochemical stability of combinations of propofol-lidocaine mixtures frequently used in clinical practice, we added lidocaine 5, 10, 20, or 40 mg to commercially available 1% propofol 20 mL. To assess chemical stability, propofol concentrations were determined by gas chromatography assay for 24 h after preparation of the mixture. In addition, scanning electron microscopy was used to determine the maximum detectable droplet size in randomly selected fields. Macroscopically, separate, colorless layers were first seen at 3 and 24 h after the addition of 40 and 20 mg of lidocaine to propofol, respectively, whereas the mixture with 5 or 10 mg of lidocaine was macroscopically stable. Propofol concentrations in the mixture with 40 mg of lidocaine decreased linearly and significantly from 4 to 24 h after preparation, whereas those combined with other lidocaine doses were unchanged compared with baseline concentrations. Scanning electron microscopy showed that droplets with diameters >or=5 microm first appeared 30 min after the addition of 40 mg of lidocaine to propofol, and the emulsion droplets were enlarged in a time- and dose-dependent fashion. Our results indicate that the addition of lidocaine to propofol results in a coalescence of oil droplets, which finally proceeds to a visible separate layer. Depending on the dose of lidocaine and the duration between its preparation and administration, this combination may pose the risk of pulmonary embolism.

IMPLICATIONS

The addition of lidocaine to propofol results in time- and dose-dependent increases in oil droplet diameters in emulsion. This mixture is physicochemically unstable over time and may cause pulmonary embolism, depending on the dose of lidocaine.

Patient-controlled sedation for outpatient thermal balloon endometrial ablation

STUDY OBJECTIVE

To evaluate the effectiveness, safety, and patient satisfaction with patient-controlled sedation during thermal balloon endometrial ablation.

DESIGN

Prospective observational study (Canadian Task Force classification II-2).

SETTING

University-affiliated teaching hospital.

PATIENTS

Thirty consecutive women with idiopathic menorrhagia refractory to medical treatment.

INTERVENTION

Thermal balloon endometrial ablation under patient-controlled sedation with a mixture of propofol and alfentanil through an analgesia pump.

MEASUREMENTS AND MAIN RESULTS

Pain was assessed using a descriptive pain score and the procedure was divided into four stages for assessment: catheter insertion, preheating phase, treatment cycle, and end of treatment. Patient satisfaction was assessed using the 8-item client satisfaction questionnaire. The procedure was well tolerated with good cooperation and no oversedation. Preheating was the most painful, and pain could be alleviated by asking the patient to self-administer a bolus of anesthesia before that phase. The median consumption of propofol was 35 mg (range 0-70 mg) and of alfentanil was 175 microg (range 50-200 microg). There were no intraoperative complications and the overall success rate in treating menorrhagia was 87%. Over 85% of the women did not think that general anesthesia was necessary. They all were highly satisfied and would recommend the procedure to others.

CONCLUSION

Patient-controlled sedation is a safe and effective method of alleviating pain and discomfort during thermal balloon ablation and is well accepted by patients.

Pharmacology of emergency department pain management and conscious sedation

The endpoints of sedation and analgesia have been more difficult than traditional physiologic parameters to measure adequately. Several clinical scoring systems have been developed in an attempt to provide more consistent and objective assessments of sedation, but the few that have been validated are cumbersome to use in the clinical setting and cannot accurately determine subtle changes in the level of sedation. Recent developments in EEG monitoring, particularly one using bispectral (BIS) analysis of the EEG signal obtained through a noninvasive forehead "lead," are promising. BIS monitoring has been used as a reliable measure of depth of midazolam-induced sedation during general anesthesia. Anesthesiologists have used this technology to prevent awareness during paralysis. One recently completed but as yet unpublished study in the ED demonstrated a high correlation with traditional sedation scales and found the device easy to use (UNC Hospitals Department of Emergency Medicine, personal communication, 1999). It is anticipated that with BIS monitoring, in combination with titratable, short-acting agents, appropriate levels of sedation can be more easily achieved while minimizing associated complications and duration of ED stay.

A randomised controlled trial of intravenous versus inhalational analgesia during outpatient oocyte recovery

To compare the efficacy and acceptability of conventional intravenous sedation with patient-controlled inhalational isodesox, 57 women undergoing outpatient oocyte recovery were randomly allocated to receive isodesox by face mask, while 55 women were given intravenous fentanyl and midazolam. Women's satisfaction with pain relief, peroperative pain, clouding of memory and the surgeons' assessment of operating conditions were evaluated. Thirty-eight women in the inhalation group (67%) and 41 (75%) women in the intravenous group were 'very satisfied' with their analgesia (p = 0. 41). The mean (SD) pain score in women given isodesox was 46.8 (34. 7), while in the intravenous group it was 34.1 (21.3) (p = 0.02). Oxygen saturation levels < 94% were recorded in one woman using isodesox and in 16 (29%) women given intravenous analgesia. Despite higher pain scores, in comparison with the conventional analgesia, patient-controlled isodesox offers a safer method of pain relief with comparable satisfaction rates.

Fast-tracking after immersion lithotripsy: general anesthesia versus monitored anesthesia care

Both monitored anesthesia care (MAC) and general anesthesia (GA) offer advantages over epidural anesthesia for immersion lithotripsy. We compared propofol-based MAC and desflurane-based GA techniques for outpatient lithotripsy. After receiving midazolam 2 mg IV, 100 subjects were randomly assigned to one of two anesthetic treatment groups. In the MAC group, propofol 50-100 microg. kg(-1). min(-1) IV was titrated to maintain an observer's assessment of alertness/sedation score of 2-3 (5 = awake/alert to 1 = asleep). Remifentanil 0.05 microg.kg(-1). min(-1) IV supplemented with 0.125 microg/kg IV boluses, was administered for pain control. In the GA group, anesthesia was induced with propofol 1.5 mg/kg IV and remifentanil 0.125 microg/kg IV and maintained with desflurane (2%-4% inspired) and nitrous oxide (60%). Tachypnea (respiratory rate >20 breaths/min) was treated with remifentanil 0.125 microg/kg IV boluses. In the GA group, droperidol (0.625 mg IV) was administered as a prophylactic antiemetic. Recovery times and postoperative side effects were assessed up to 24 h after the procedure. Compared with MAC, the use of GA reduced the opioid requirement and decreased movements and episodes of desaturation (<90%) during the procedure. Although the GA group took longer to return to an observer's assessment of alertness/sedation score of 5, discharge times were similar in both groups. We conclude that GA can provide better conditions for outpatient immersion lithotripsy than MAC sedation without delaying discharge.

IMPLICATIONS

A desflurane-based general anesthetic technique using the cuffed oropharyngeal airway device was found to be a highly acceptable alternative to propofol-based monitored anesthesia care sedation for outpatient immersion lithotripsy.

A clinical trial of propofol vs midazolam for procedural sedation in a pediatric emergency department

OBJECTIVE

To compare the effectiveness, recovery time from sedation, and complication rate of propofol with those of midazolam when used for procedural sedation in the pediatric emergency department (PED).

METHODS

A prospective, blinded, randomized, clinical trial comparing propofol and midazolam was conducted in the PED of a tertiary pediatric center. Eligible patients were aged 2-18 years with isolated extremity injuries necessitating closed reduction. All patients received morphine for pain, then were randomized to receive propofol or midazolam for sedation. Vital signs, pulse oximetry, and sedation scores were recorded prior to sedation and every 5 minutes thereafter until recovery. Recovery time, time from cast completion to discharge, and other time intervals during the PED course and all sedation-related complications were also recorded.

RESULTS

Between August 1996 and October 1997, 91 patients were enrolled. Demographic data, morphine doses, and sedation scores were similar between the propofol and midazolam groups. Mean +/- SD recovery time for the propofol group was 14.9+/-11.1 minutes, compared with 76.4+/-47.5 minutes for the midazolam group, p<0.001. Mild transient hypoxemia was the most significant complication, occurring in 5 of 43 (11.6%) patients given propofol and 5 of 46 (10.9%) patients given midazolam (odds ratio 1.08, 95% CI = 0.24 to 4.76).

CONCLUSION

In this study, propofol induced sedation as effectively as midazolam but with a shorter recovery time. Complication rates for propofol and midazolam were comparable, though the small study population limits the power of this comparison. Propofol may be an appropriate agent for sedation in the PED; however, further study is necessary before routine use can be recommended.

Spinal analgesia for transvaginal oocyte retrieval

Day case transvaginal ultrasound-guided needle puncture is currently the method of choice for oocyte retrieval. The risk of morbidity from this procedure increases with sudden patient movement in response to needle manipulation. The provision of effective pain relief can limit this risk, but is complicated by the need to balance efficacy with day case compatibility. The aim of this pilot study was to establish whether spinal analgesia using a mixture of bupivacaine and fentanyl could be useful in this context. The results identify several advantages of this technique over current clinical practice, and merit further comparative investigation.

Propofol and fentanyl compared with midazolam and fentanyl during third molar surgery

PURPOSE

The purpose of this study was to measure the safety and efficacy of propofol combined with fentanyl as sedative agents during third molar outpatient surgery.

PATIENTS AND METHODS

A double-blind, prospective, randomized clinical trial involving 57 patients undergoing removal of third molars under intravenous sedation between November 1994 and December 1995 was performed. Patients randomly received either propofol and fentanyl (P + F, th = 24) or midazolam and fentanyl (M + F, M = 33). Patient demographics, Corah anxiety scores, and physiologic parameters were determined preoperatively. All medications were titrated to the same clinical end point for sedation. Intraoperative physiologic parameters, cooperation, alertness, and pain scores were assessed. Postoperative recovery and degree of amnesia also were determined.

RESULTS

There were no significant differences in either patient demographics or surgical characteristics between groups. The P + F group was significantly less cooperative than the M + F group. Pain during injection of propofol was a significant adverse side effect. Both groups experienced a small percentage of apneic episodes, but mechanical ventilation was never required. There were no differences in recovery between groups as measured by the Treiger dot test and psychomotor recovery scores. The degree of anterograde amnesia was greater for the M + F group, although the difference was not statistically significant. Sedation was rated good to excellent by the patient, surgeon, and observer, and there were no statistically significant differences between groups.

CONCLUSION

Propofol appears to be a safe and efficacious drug for use during outpatient oral surgical procedures.

Use of alfentanil and propofol for outpatient monitored anesthesia care: determining the optimal dosing regimen

Propofol and alfentanil are both rapid and short-acting drugs that can be used for sedation and analgesia during monitored anesthesia care (MAC). This study was designed to determine the optimal infusion rates of propofol and alfentanil when administered during local anesthesia. In this randomized, double-blind study, we evaluated the effects of different propofol infusion rates on the alfentanil requirement, level of sedation, intraoperative recall, respiratory and cardiovascular variables, and recovery. Seventy-two consenting ASA physical status I or II female outpatients undergoing breast biopsy procedures with local anesthesia were randomly assigned to one of four treatment groups. All patients received midazolam, 2 mg intravenously (I.V.) for premedication. Propofol was infused at 0, 25, 50, or 75 microg x kg(-1) x min(-1) during the operation. Sedation was evaluated using the Observer's Assessment of Alertness/Sedation (OAA/S) scale at 5-min intervals by a blinded observer. Two minutes before the infiltration of the local anesthetic solution, a bolus of alfentanil, 2.5 microg/kg I.V., was administered, followed by a maintenance infusion of 0.5 microg x kg(-1) x min(-1). The alfentanil infusion rate was subsequently varied to maintain patient comfort and stable cardiovascular and respiratory function. Pictures were shown at the start of the propofol infusion, upon initiating the alfentanil infusion, and at 45 min after the skin incision to evaluate recall of intraoperative events. Propofol produced dose-dependent increases in the level of sedation (with median OAA/S scores of 2-4, P < 0.05). Higher infusion rates of propofol (50-75 microg x kg(-1) x min(-1)) produced significant amnesia, opioid-sparing effects (alfentanil 0.3 +/- 0.2 vs 0.6 +/- 0.2 microg x kg(-1) x min(-1)), and less postoperative nausea and vomiting (P < 0.05). However, episodes of transient hemoglobin oxygen desaturation were more common in the deeply sedated patients. Thus, in healthy outpatients premedicated with midazolam, 2 mg I.V., a propofol infusion of 25-50 microg x kg(-1) x min(-1) in combination with an alfentanil infusion of 0.2-0.4 microg x kg(-1) x min(-1) is recommended for sedation and analgesia during MAC in the ambulatory setting.

IMPLICATIONS

Sedation is often given during local anesthesia. This study demonstrated that administration of an intravenous anesthetic, propofol, in combination with an opioid infusion (i.e., alfentanil) to provide sedation analgesia and amnesia with a low incidence of side effects, such as nausea and vomiting and respiratory depression in outpatients premedicated with midazolam.

Safe anesthetic management of patients undergoing a novel method of treating human hepatocellular cancer

STUDY OBJECTIVE

To evaluate the safety and efficacy of monitored anesthesia care (MAC) in patients who undergo a novel treatment for hepatocellular cancer in which procedure-related hemodynamic instability is problematic.

DESIGN

Nonrandomized open study.

SETTING

University cancer center operating room.

PATIENTS

Nine patients scheduled for hepatic arterial infusion of doxorubicin with complete hepatic venous isolation and extracorporeal chemofiltration (no more than 3 procedures per patient).

INTERVENTIONS

Hepatic venous isolation was achieved with a dual-balloon inferior vena cava catheter connected to an extracorporeal circuit containing chemofilters. Doxorubicin was infused through the hepatic artery and filtered from the venous blood, which was returned to the patient through an internal jugular venous catheter. Each patient received a bolus of propofol (200 micrograms/kg) and one of alfentanil (2 micrograms/kg) followed by simultaneous infusions of propofol and alfentanil for percutaneous placement of the catheters and operation of the extracorporeal circuit. Drug rates were varied to maintain a sedative-analgesic state of calm, comfort, minimal movement, and adequate respiratory function. Prior to circuit initiation, patients were preloaded with crystalloid. During circuit operation, hypotension was treated with intravenous (IV) phenylephrine and crystalloid.

MEASUREMENTS AND MAIN RESULTS

End-tidal CO2 (PETCO2), respiratory rate, oxygen saturation (SaO2), arterial blood pressure (BP), and heart rate (HR) were monitored. Systolic, diastolic, and mean arterial pressure (MAP), and HR were compared before, during, and after hepatic venous isolation and chemofiltration. Doses and infusion rates of propofol, alfentanil, and phenylephrine were recorded for each treatment. Hypotension occurred in 11 of 13 procedures when blood was directed through the chemofilters and was successfully treated with phenylephrine (dose range 40 to 5,733 micrograms) and crystalloid. Blood pressure returned to the baseline value on termination of the circuit. Throughout the sedation, patients were easily arousable, analgesia was adequate, and PETCO2 level of 38 +/- 4 mmHg and SaO2 greater than 94% were maintained. Mean doses and infusion rates of MAC drugs were, respectively: propofol, 261 +/- 88 mg and 23.7 +/- 3.6 micrograms/kg/min; alfentanil, 3,350 +/- 1,468 micrograms and 0.32 +/- 0.14 microgram/kg/min.

CONCLUSIONS

Patients undergoing this novel cancer treatment are safely and effectively managed by MAC achieved with simultaneous infusions of alfentanil and propofol. Procedure-associated hypotension is easily treated with IV phenylephrine and crystalloid.

The effect of propofol on parthenogenetic activation, in vitro fertilization and early development of mouse oocytes

OBJECTIVE

To assess the effect of propofol on fertilization and early embryo development in a mouse IVF model.

DESIGN

Controlled study.

SETTING

Mouse IVF.

INTERVENTION(S)

Mouse oocytes were exposed in vitro to propofol at a concentration of 0 (control), 50, 250, 500, 1,000, or 5,000 ng/mL for 30 minutes, washed, and inseminated. Thereafter, fertilization was assessed. Subsequent in vitro development to the blastocyst stage was monitored daily. The potential to activate parthenogenetically oocytes also was evaluated by looking for spontaneous extrusion of the second polar body or development to the two-cell stage. In a second step, a pure propofol solution was added to culture medium and used as a standard.

MAIN OUTCOME MEASURE(S)

Two-cell and blastocyst-stage embryo.

RESULT(S)

Where fertilization occurred, subsequent embryo cleavage and development up to the blastocyst stage was affected significantly by the presence of propofol solution in the medium, (i.e., 3% to 41%) in comparison with the control group (76%). Exposure of unfertilized oocytes for 30 minutes to propofol results in a parthenogenetic activation of 33% to 60%, which was significantly higher than the control (10%). When oocytes were kept in propofol for 24 hours, a mean of 30% of activation was observed as compared with 0.5% for the control.

CONCLUSION(S)

We can conclude from these experiments that even a brief exposure of cumulus-enclosed oocytes to a low concentration of propofol is deleterious to subsequent cleavage. Exposure of unfertilized oocytes to propofol results in a high degree of parthenogenetic activation.

Compatibility of propofol, fentanyl, and vecuronium mixtures designed for potential use in anesthesia and patient transport

STUDY OBJECTIVE

To determine whether propofol emulsion, fentanyl, and vecuronium remain compatible and stable when mixed in clinically appropriate concentrations.

DESIGN

Seven separate in vitro experiments. Two different propofol-fentanyl-vecuronium mixtures were formulated. Regular assays of propofol, fentanyl, and vecuronium were performed during a 90-minute infusion period and also during storage of one of the mixtures for 30 days at 4 degrees C, 22 degrees C, and 30 degrees C. Initial and storage pH were determined, and assays of the three drugs were performed when pH of the mixtures was varied between 1.4 and 12.7. Emulsion stability was assessed by measuring immediate and delayed alterations in droplet charge (zeta potential) and size. Finally, samples of the stored mixtures were incubated in culture medium for one week.

SETTING

Teaching hospital and university laboratories.

MEASUREMENTS AND MAIN RESULTS

Concentrations of the three drugs remained unchanged during infusion. During storage, concentrations of all three drugs were stable for two weeks at 4 degrees C or 22 degrees C, and for several days at 30 degrees C. Initial pH of the two mixtures was 5.1 and 5.3, and pH of the stored mixture increased slowly after 8 days. When the pH of mixtures was greater than or equal to 5.6, concentrations of fentanyl and vecuronium were unstable, but the concentration of propofol remained unchanged. Despite a reduction in zeta potential, immediate droplet size was essentially unchanged. No microbial growth was detected in stored mixtures.

CONCLUSION

The propofol, fentanyl, and vecuronium mixtures studied were compatible and stable immediately after mixing. Appropriate in vitro compatibility testing is recommended before clinical evaluation of propofol-opioid or propofol-opioid-muscle relaxant mixtures.

The use of propofol for sedation in the emergency department

OBJECTIVE

To evaluate the effectiveness of propofol and fentanyl when used by emergency physicians (EPs) for systemic sedation and analgesia in the ED.

METHODS

Over an eight-month period, a convenience sample of consenting patients at an urban teaching hospital ED who required sedation for painful procedures were enrolled in a descriptive study of therapeutic propofol sedation. After receiving 2 micrograms/kg of fentanyl i.v. the patients received a continuous infusion of propofol at 0.21 mg/kg/min i.v. to the desired level of sedation. A maintenance infusion of 3-6 mg/kg/hr was administered during the remainder of the procedure. Sedation time, total procedure time, and recovery time were recorded and the presence of side effects was noted. The patients and the physicians rated their satisfaction with the technique on a 100-mm visual analog scale. The patients were contacted at 24 hours for follow-up information.

RESULTS

Twenty patients (aged 19-62 years) received propofol infusion for procedures that included ten abscess incision and drainages, eight orthopedic reductions, one chest tube placement, and one wound exploration. The mean (+/- SD) total dose of propofol was 200 +/- 160 mg. The mean time to onset of sedation was 6.6 +/- 3.2 min, the mean procedure interval was 9.6 +/- 6.3 min, and the mean interval until recovery was 6.1 +/- 4.1 min. The median patient satisfaction score was 97 mm (range 40-100 mm); the median rating by physicians was 88 mm (range 4-100 mm). Side effects were noted in six patients: three had pain on injection, one had pain on injection and brief (< 1 min) hypotension (systolic blood pressure = 80 mm Hg), and two had apnea (< 30 sec). Seven patients had some recall of the procedure immediately afterwards, but only five had any recall at 24 hours. All 20 patients stated they would be willing to receive the same sedation again for a future procedure.

CONCLUSION

Propofol appears to be an effective agent to provide systemic sedation and analgesia when used in conjunction with fentanyl for procedures in the ED. Given its rapidity of onset and elimination, it may become a useful agent to EPs for i.v. sedation in the ED.

A comparison between total intravenous anaesthesia using a propofol/alfentanil mixture and an inhalational technique for laparoscopic gynaecological sterilization

Thirty patients undergoing laparoscopic gynaecological sterilization, as day-cases, were randomly allocated to receive either total intravenous anaesthesia (TIVA) with a propofol and alfentanil mixture or a standard inhalational technique. Immediate recovery, as measured by times to awakening, co-operation and orientation, and psychomotor recovery, as measured by 'P' deletion studies, were not significantly different between the two groups. TIVA produced a significant reduction in post-operative nausea at both 1 and 2 h post-operatively, as measured by a visual analogue scale (P < 0.01). No patient in the TIVA group vomited whereas two vomited in the inhalational group. There were no differences between the two groups with respect to suitability for discharge home and no incidences of awareness. We conclude that TIVA with a propofol and alfentanil mixture provides satisfactory anaesthesia for gynaecological sterilization, with good recovery characteristics and a low incidence of post-operative nausea and vomiting.

True patient-controlled sedation

A modified patient-controlled analgesia pump provided doses of propofol 3 mg or midazolam 0.1 mg in 0.3 ml, over 5.4 s, with no lockout, during transvaginal oocyte retrieval. Alfentanil 0.2 mg was administered at three points during the procedure, and on request. Patients were randomly assigned to receive either propofol (25 patients) or midazolam (22 patients). The mean age, weight, duration of procedure and dose of alfentanil were similar in both groups. Onset of sedation with propofol or midazolam took 70.6 (SD 22.4) and 106.3 (50.7) s respectively. Mean doses over the first 5 min were midazolam 2.7 (1.2) mg, and propofol 54 (18) mg. Thereafter requirements decreased: midazolam 0.065 (0.065) mg.min-1, propofol 2.1 (1.3) mg.min-1. All patients successfully completed the procedure; none required additional sedation. P-deletion, reaction time, and critical flicker fusion tests revealed similar depression in both groups immediately postoperatively. After 30 min the p-deletion and critical flicker fusion scores were still impaired in the midazolam, but not in the propofol, group.