Comparison of alfentanil with fentanyl for outpatient anesthesia

The Effect of Alfentanil on Emergence Delirium Following General Anesthesia in Children: A Randomized Clinical Trial

BACKGROUND

Emergence delirium can occur after general anesthesia in children. An intravenous infusion of alfentanil may reduce the incidence or severity of emergence delirium after sevoflurane anesthesia.

OBJECTIVE

The study aimed to investigate the effects of alfentanil intravenous infusion on emergence delirium and other perioperative complications.

METHOD

This was a single-center, randomized, placebo-controlled, double-blind clinical trial. A total of 172 children undergoing ambulatory dental treatment were randomized into three groups. Alfentanil group Alf2 received 0.2 μg/kg/min of alfentanil for continuous infusion, alfentanil group Alf4 received 0.4 μg/kg/min alfentanil, and the saline group (group Sal) received a continuous infusion of normal saline, with the same volume as the two other groups, as a placebo. The incidence of emergence delirium (assessed by the Paediatric Anaesthesia Emergence Delirium [PAED] scale), hemodynamic parameters, and recovery characteristics were recorded during the recovery period. The Aono scale was also used to assess for emergence delirium. A WeChat applet was designed to facilitate a caregiver teleconsultation and to provide feedback on postoperative nausea and vomiting and any other complications after discharge.

RESULTS

The incidence of emergence delirium in group Alf2 (22.9%) and group Alf4 (21.1%) was significantly lower than that observed in the Sal group (48.3%). The PAED scores in group Alf2 (6.4 ± 3.5) and group Alf4 (5.8 ± 3.8) were significantly lower than those for group Sal (9.6 ± 5.1) (p < 0.01). Ten children in the Alf4 group needed manual ventilatory assistance to maintain end-tidal carbon dioxide (ETCO₂) < 55 mm; children in group Alf2 did not. There was no significant difference between the discharge time of groups Alf2 and Sal (31.2 ± 4.64 vs 30.5 ± 2.82 min; 0.659 [95% confidence interval {CI} -1.052 to 2.369], p = 0.643); the time to discharge of group Alf4 (35.16 ± 3.97 min) was significantly longer than that of groups Alf2 and Sal (p < 0.01). The incidence of nausea and vomiting was similar in the three groups. No other clinically relevant adverse events were observed.

CONCLUSIONS

Intravenous infusion of 0.2 μg/kg/min and 0.4 μg/kg/min alfentanil decreased the incidence of emergence delirium in the post-anesthesia care unit. The 0.2 μg/kg/min dose of alfentanil resulted in less respiratory depression and discharge delay than the 0.4 μg/kg/min alfentanil dose.

TRIAL REGISTRATION

Chinese Clinical Trial Registry (ChiCTR2100043320).

Comparison of Sedation with Dexmedetomidine Alfentanil Versus Ketamine-Alfentanil in Patients Undergoing Closed Reduction of Nasal Fractures

Objectives

To compare the sedative effects of dexmedetomidine alfentanil versus ketamine-alfentanil in patients undergoing closed reduction of nasal fractures on the basis of intraoperative hemodynamic changes, satisfaction of patients and surgeons, and the adverse effects.

Methods

Sixty patients with ASA class 1 or 2 were randomized to either of two groups, a dexmedetomidine alfentanil group (DA group; n = 30) or a ketamine-alfentanil group (KA group; n = 30). Hemodynamic parameters, oxygenation status, adverse events, the satisfaction of patients and surgeons, and postoperative pain scores by visual analog scale (VAS) were recorded at specific time intervals during the trial.

Results

Systolic blood pressure was significantly lower in the DA group than in the KA group from T1 min to T15 min. The duration of the recovery ward stay was longer in the DA group; however, two groups were similar in terms of total anesthesia time and awakening time. Likewise, two groups were similar in terms of the patient and surgeon’s satisfaction, pain scores, and the occurrence of adverse effects.

Conclusions

Both sedation methods were safely performed, and dexmedetomidine-alfentanil is as effective as ketamine-alfentanil in patients undergoing short-term operations such as nasal fracture corrections.

Effect of ketamine versus alfentanil following midazolam in preventing emergence agitation in children after sevoflurane anaesthesia: A prospective randomized clinical trial

Objective

To investigate the effect of intranasal ketamine versus alfentanil in addition to oral midazolam for the prevention of emergence agitation in children.

Methods

Children undergoing urological surgery with sevoflurane anaesthesia received oral midazolam 40 min before induction and were then randomly assigned to receive 2 mg/kg ketamine, 10 µg/kg alfentanil or 1 ml isotonic saline intranasally. Parental separation status and mask acceptance were assessed preoperatively. Emergence agitation was evaluated using a paediatric anaesthesia emergence delirium (PAED) score.

Results

Data from 78 children were evaluated in the study. There were no significant differences between the groups in demographic characteristics, recovery times or parental separation scores . Mask acceptance was significantly better in the ketamine group than in the saline group . The mean PAED score in the ketamine group was significantly better than in the other two groups, but was similar in the saline and alfentanil groups. The incidence of emergence agitation was 3.8%, 36.0% and 40.7% in the ketamine, alfentanil and saline groups, respectively.

Conclusions

The addition of intranasal ketamine to oral midazolam significantly improved the quality of induction and reduced sevoflurane-induced emergence agitation, in children undergoing urological surgery.

Comparison between the recovery time of alfentanil and fentanyl in balanced propofol sedation for gastrointestinal and colonoscopy: a prospective, randomized study

Background

There is increasing interest in balanced propofol sedation (BPS) titrated to moderate sedation (conscious sedation) for endoscopic procedures. However, few controlled studies on BPS targeted to deep sedation for diagnostic endoscopy were found. Alfentanil, a rapid and short-acting synthetic analog of fentanyl, appears to offer clinically significant advantages over fentanyl during outpatient anesthesia.

It is reasonable to hypothesize that low dose of alfentanil used in BPS might also result in more rapid recovery as compared with fentanyl.

Methods

A prospective, randomized and double-blinded clinical trial of alfentanil, midazolam and propofol versus fentanyl, midazolam and propofol in 272 outpatients undergoing diagnostic esophagogastroduodenal endoscopy (EGD) and colonoscopy for health examination were enrolled. Randomization was achieved by using the computer-generated random sequence. Each combination regimen was titrated to deep sedation. The recovery time, patient satisfaction, safety and the efficacy and cost benefit between groups were compared.

Results

260 participants were analyzed, 129 in alfentanil group and 131 in fentanyl group. There is no significant difference in sex, age, body weight, BMI and ASA distribution between two groups. Also, there is no significant difference in recovery time, satisfaction score from patients, propofol consumption, awake time from sedation, and sedation-related cardiopulmonary complications between two groups. Though deep sedation was targeted, all cardiopulmonary complications were minor and transient (10.8%, 28/260). No serious adverse events including the use of flumazenil, assisted ventilation, permanent injury or death, and temporary or permanent interruption of procedure were found in both groups. However, fentanyl is New Taiwan Dollar (NT$) 103 (approximate US$ 4) cheaper than alfentanil, leading to a significant difference in total cost between two groups.

Conclusions

This randomized, double-blinded clinical trial showed that there is no significant difference in the recovery time, satisfaction score from patients, propofol consumption, awake time from sedation, and sedation-related cardiopulmonary complications between the two most common sedation regimens for EGD and colonoscopy in our hospital. However, fentanyl is NT$103 (US$ 4) cheaper than alfentanil in each case.

Trial registration

Institutional Review Board of Buddhist Tzu Chi General Hospital (IRB097-18) and Chinese Clinical Trial Registry (ChiCTR-TRC-12002575)

Median effective infusion dose (ED50) of alfentanil for monitored anesthesia care of percutaneous vertebroplasty of osteoporotic fractures

Percutaneous vertebroplasty (PVP) consists of injecting small quantities of orthopedic cement to consolidate pathologic vertebral bodies. The procedure is brief but painful during vertebral puncture and cement injection requiring either general anesthesia or monitored anesthesia care with opioids. The optimal dose of alfentanil in this setting is unknown. Therefore, we sought to determine its median effective dose (ED50, or analgesic efficacy in 50% of patients) during PVP in none intubated, spontaneously breathing patients. After approval and informed consent of the Institutional Review Board, 50 patients (American Society of Anesthesiologists II-III, age 50 to 80, weight: 53 to 82 kg) with osteoporotic vertebral fractures were enrolled. The patients were premedicated with oral hydroxyzine 100 mg and had skin infiltration with 50 mg lidocaine before vertebral puncture. The prone position was adopted and oxygen was provided via a facemask. Noninvasive cardiorespiratory variables were monitored. Pain was evaluated by a numerical pain scale (NPS) where 0 represents no pain and 10 the worst tolerable pain. Alfentanil infusion was started 30 minutes before vertebral puncture. The initial dose was 2.0 mg/h. Thereafter, a 0.05 mg/h decrease or increase was applied to the next patient if analgesia was effective (NPS: 3 or less) or not (NPS>3) according to the Dixon method. The bootstrap resampling technique was used to calculate the ED50 and its 95% confidence limits. The latter was 1.05 mg/h (95% confidence interval, 1.0-1.2). Transient apnea (n=2) and nausea/vomiting (n=3) were observed. Given the median body weight of the patients (65 kg), we conclude that 0.27 microg kg/min of alfentanil provides effective analgesia for PVP under monitored anesthesia care.

SUMMARY STATEMENT

PVP consists of injecting small quantities of orthopedic cement to consolidate pathologic vertebral bodies. The median effective dose (ED50) for pain relief during vertebral puncture and cement injection is 1.05 (95% confidence interval, 1.0-1.2) mg/h when infusion is started 30 minutes before the procedure. Given the median body weight of our study population (65 kg), this dose corresponds to 0.27 microg kg/min.

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.

A Comparison of Effects of Alfentanil, Fentanyl, and Remifentanil on Hemodynamic and Respiratory Parameters During Stereotactic Brain Biopsy

The aim of this study was to compare the effects of 3 different sedative-analgesic regimens in patients with intracranial mass lesions undergoing stereotactic brain biopsy. A 135 outpatients with American Society of Anesthesiologists I to II were divided into 3 groups: group A (n = 45) received a loading dose of IV alfentanil 7.5 microg/kg followed by infusion rate of 0.25 microg/kg/min; group F (n = 45) received a bolus dose of 1 microg/kg IV fentanyl and repeated as needed; and group R (n = 45) received infusion of 0.05 microg/kg/min remifentanil. Target level of sedation was 3 to 4 of the Ramsay Sedation Scale. Systolic and diastolic blood pressure, heart rate, respiratory rate, peripheric oxygen saturation (SpO2), and end-tidal carbon dioxide were recorded at different stages of the procedures. The patients in group F had significantly lower mean heart rate than those in groups A and R, but this was not in the limits of the bradycardia. The patients in group A had significantly lower mean SpO2 than those in the other groups, but mean SpO2 values did not drop below 94%. There were no significant differences in end-tidal carbon dioxide and respiratory rate values among the groups. Our results suggest that all 3 regimens have relatively similar hemodynamic and respiratory responses. The use of bolus fentanyl technique caused less hemodynamic stability. The continuous infusion technique of remifentanil or alfentanil provided better control on hemodynamic parameters.

Emetic effects of morphine and piritramide

BACKGROUND

Successful management of postoperative pain requires that adequate analgesia is achieved without excessive adverse effects. Opioid-induced nausea and vomiting is known to impair patients' satisfaction, but there are no studies providing sufficient power to test the hypothesis that the incidence of opioid-induced nausea and vomiting differs between micro -opioid receptor agonists. Thus, we tested the hypothesis that the incidence of vomiting and nausea differs between morphine and piritramide.

METHODS

In a prospective, randomized, double-blind fashion, we administered either morphine (n=250) or piritramide (n=250) by patient-controlled analgesia (PCA) for postoperative pain relief. We used a bolus dose of 1.5 mg with a lockout time of 10 min. Incidence and intensity (numerical rating scale) of postoperative nausea, vomiting, pain, patient satisfaction (score 0-10), side-effects (score 0-3) and drug consumption were measured.

RESULTS

Mean drug consumption did not differ between the piritramide and morphine groups (30.8 (SD 22.4) mg day(-1) vs 28.4 (21.8) mg day(-1)) during the first postoperative day and there were no significant differences in the overall incidence of nausea (30% vs 27%) and vomiting (19% vs 15%). Intensity of nausea correlated inversely (P=0.01) with morphine consumption but not with piritramide consumption. Pain scores both at rest (2.2 (1.9) vs 2.6 (2)) and during movement (4.4 (2.2) vs 4.9 (2.3)) were slightly but significantly less with morphine.

CONCLUSIONS

Opioid-induced emesis was observed in about one-third of the patients using morphine and piritramide for PCA and the incidence of vomiting was one-half of that. Potential differences in the incidence of vomiting during PCA therapy between these micro-opioid receptor agonists can be excluded.

Effects of fentanyl on pain and hemodynamic response after retrobulbar block in patients having phacoemulsification

PURPOSE

To determine the effects of systemic fentanyl analgesia in preventing the pain related to the administration of retrobulbar anesthesia and cataract surgery.

SETTING

Departments of Ophthalmology and Anesthesiology, School of Medicine, Kocatepe University, Afyon, Turkey.

METHODS

One hundred twenty patients with American Society of Anesthesiologists physical status I to III scheduled for cataract surgery were evaluated in a single-blind randomized study. Patients with a history of hypertension, hyperthyroidism, or neurologic or psychiatric disorders were excluded. In the study (fentanyl) group, an intravenous bolus of fentanyl 2 microg/kg was slowly given 5 minutes before retrobulbar anesthesia was administered. In the control group, fentanyl was not given. There were 60 patients in each group. Demographic data were not statistically different between the 2 groups. The intensity of pain during injection and intraoperatively was measured by verbal pain scores. Hemodynamic stability was assessed by the heart rate (HR) and mean arterial pressure (MAP). End-tidal carbon dioxide concentrations and oxygen saturations were also recorded.

RESULTS

The changes in HR and MAP at 0, 10, 20, and 30 minutes were statistically significant between the fentanyl and control groups (P<.05). Fentanyl reduced pain scores significantly at all evaluations (P<.05).

CONCLUSION

The results suggest that fentanyl preemptively decreases injection and intraoperative hyperalgesia and provides hemodynamic stability without affecting patient cooperation, resulting in cataract surgery with retrobulbar anesthesia that is comfortable for both surgeon and patient.

Sedation for outpatient endometrial biopsy: comparison of remifentanil-propofol and alfentanil-propofol

The purpose of the study was to compare the clinical activity of remifentanil or alfentanil under propofol sedation with regard to respiratory rate, sedation and recovery rate when used for outpatient endometrial biopsy. Patients were randomized to receive intravenously either bolus remifentanil 0.4 microgram/kg and propofol 1 mg/kg in the remifentanil group (n = 30), or bolus alfentanil 20 micrograms/kg and propofol 1 mg/kg in the alfentanil group (n = 30). Patients were monitored for heart rate, systolic and diastolic arterial pressure, peripheral O2 saturation (SpO2), respiration rate, and Aldrete sedation score. Pulse oximetry was used to monitor heart rate and SpO2 during endometrial biopsy. Apnoea was observed in five patients from the remifentanil group, and in three patients from the alfentanil group. The groups did not differ with regard to apnoea incidences. Times were recorded for orientation and Aldrete score > 8, and were similar between the two groups (13.20 +/- 3.64 min and 14.0 +/- 3.87 min in the remifentanil group, 14.7 +/- 3.64 min and 15.9 +/- 3.15 min in the alfentanil group, respectively). The sedative and analgesic combination of remifentanil-propofol does not offer any advantages compared with a combination of alfentanil-propofol with regards to respiration and recovery during sedation for outpatient endometrial biopsy.

Postoperative nausea and vomiting after total intravenous anesthesia with propofol and remifentanil or alfentanil: how important is the opioid?

STUDY OBJECTIVE

To compare the frequency and duration of postoperative nausea and vomiting (PONV) following total intravenous anesthesia (TIVA) with propofol and either remifentanil or alfentanil in outpatients undergoing arthroscopic surgery of the extremities.

DESIGN

Randomized, third-party blinded study.

SETTING

University medical center.

PATIENTS

100 ASA physical status I and II patients scheduled for arthroscopic surgery of the knee or shoulder.

INTERVENTIONS

The anesthesia regimen consisted of a bolus followed by continuous infusion of propofol (2 mg/kg followed by 120 microg/kg/min) and the opioid (remifentanil 0.5 microg/kg followed by 0.1 microg/kg/min or alfentanil 10 microg/kg followed by 0.25 microg/kg/min). Patients breathed 100% oxygen spontaneously through a Laryngeal Mask Airway (or an endotracheal tube when medically indicated). Opioids were titrated to maintain blood pressure and heart rate within 20% of baseline and a respiratory rate of 10 to 16 breaths/min. Propofol was titrated downward as low as possible without permitting patient movement.

MEASUREMENTS

Nausea was determined by an 11-point categorical scale and was recorded before surgery and multiple time points thereafter. The times of emetic episodes were recorded. Treatment of PONV was at the discretion of the postanesthesia care unit (PACU) nurses who were blinded to the identity of the opioid used.

MAIN RESULTS

Nausea scores were 0 at all time points in over 70% of the patients in each group. None of the 100 patients vomited while in the hospital, and only one patient required antiemetic therapy.

CONCLUSION

When propofol-based TIVA is used for arthroscopic surgery, short-acting opioids do not significantly affect the risk of PONV.

Relationship between clinical endpoints for induction of anesthesia and bispectral index and effect-site concentration values

STUDY OBJECTIVE

To assess the relationship between clinical endpoints for induction of anesthesia and the electroencephalographic (EEG) bispectral index (BIS) and effect-site concentration (C(E)) values when using a target-controlled infusion (TCI) of either thiopental sodium or propofol, by hypothesizing that yawning may be a useful alternative to other commonly used clinical signs for determining loss of consciousness.

DESIGN

Randomized observational clinical study.

SETTING

Operating room of a university-based hospital.

PATIENTS

60 healthy adult patients (aged 20-50 yrs) scheduled for elective surgery with general anesthesia.

INTERVENTIONS

During a TCI of propofol (n = 30) or thiopental (n = 30), clinical endpoints for loss of verbal responsiveness (LOV), loss-of-eyelash reflex (LOE), occurrence of yawning, and apnea were assessed at 15-second intervals. In addition, BIS and C(E) values were recorded at each of the endpoints.

MEASUREMENTS AND MAIN RESULTS

In both anesthetic groups, the sequence of occurrence of the clinical endpoints was similar, namely LOV, LOE, yawning, and, lastly, apnea. Compared with LOV and LOE, yawning was associated with lower BIS and higher C(E) values with both anesthetics. The frequency of yawning was higher with thiopental than propofol (83% vs. 63%, respectively). However, the frequency of apnea was higher with propofol than thiopental (77% vs. 53%, respectively).

CONCLUSION

The correlation of the clinical endpoints with BIS and C(E) values was highest for LOV. Yawning was as unreliable as LOE for determining the onset of unconsciousness during induction of anesthesia. This clinical sign failed to be observed in 17% and 37% of patients induced with thiopental and propofol, respectively.

The concentration-effect relationship of the respiratory depressant effects of alfentanil and fentanyl

The relative potencies of fentanyl and alfentanil for respiratory depression were determined in eight healthy male volunteers in a double-blinded, randomized study with a cross-over design. The drugs were delivered by computer-driven infusion with logarithmically ascending plasma concentrations until the respiratory rate reached 2/min and/or oxygen saturation decreased below 85% with subjects breathing room air. Ventilation was measured with respiratory inductive plethysmography, indirect calorimetry, and arterial blood gas analysis, and plasma drug concentrations were determined. Pharmacodynamic modeling was performed using a fractional E(max) model for minute volume and respiratory rate and the concentrations producing 50% depression (i.e., apparent 50% effective concentration [EC(50)] values) were determined. Both drugs decreased ventilation in a similar manner, and drug infusions were terminated at mean +/- SD measured plasma concentrations of 254 +/- 88 ng/mL and 5.1 +/- 1.7 ng/mL for alfentanil and fentanyl, respectively. Alfentanil decreased minute volume from baseline by 54% +/- 19% and respiratory rate by 40% +/- 11% with EC(50) values of 234 +/- 57 ng/mL and 195 +/- 101 ng/mL. The respective decreases for fentanyl were 50% +/- 11%, 41% +/- 15%, and the estimated EC(50) values were 6.1 +/- 1.4 ng/mL and 3.5 +/- 1.4 ng/mL, respectively. Using the apparent EC(50) values, the calculated potency ratio for alfentanil:fentanyl was (mean and 95% confidence interval) 1:39 (1:31-1:46) for minute volume and 1:51 (1:34-1:68) for respiratory rate. This is analogous to the analgesic effect studied earlier. The findings support the notion of parallel analgesic and respiratory depressant effects of alfentanil and fentanyl. Therefore equianalgesic concentrations of both drugs will lead to equally pronounced respiratory depression.

IMPLICATIONS

This double-blinded, randomized study evaluated the potency ratio of alfentanil and fentanyl-induced respiratory depression. The findings support the notion of parallel analgesic and respiratory depressant effects of alfentanil and fentanyl. Therefore equianalgesic concentrations of both drugs will lead to equally pronounced respiratory depression.

Rand-Stein analgesia protocol for cataract surgery

OBJECTIVE

To describe the safety and efficacy of an analgesia protocol that enables the surgeon to maintain control over an alert patient experiencing seemingly painless ambulatory cataract surgery, while eliminating the risks and side effects associated with general, local, topical, and intracameral anesthesia.

DESIGN

Noncomparative, interventional case series.

PARTICIPANTS

Five thousand one hundred sixty-eight consecutive cataract surgery cases operated on by the same surgeon from April 1, 1993 through June 1, 1998.

METHODS

This technique produces profound ocular analgesia, avoiding any undesired sedative effects, using very low-dose, titrated, intravenous alfentanil. Complete control of the uncooperative patient, including lid squeezing and ocular and general body movements, is obtainable whenever necessary using very low-dose, titrated, intravenous methohexital.

MAIN OUTCOME MEASURES

Success was defined as surgery completed in a controlled manner without the need to convert to general, local, topical, or intracameral anesthesia and the patient's experience being perceived as pain free.

RESULTS

One hundred percent of the cases were successful without ever deviating from the protocol.

CONCLUSIONS

This analgesia protocol offers advantages for cataract surgery. It virtually eliminates the morbidity of cataract surgery associated with other anesthesia techniques while providing excellent and reliable control. It allows for an immediate postoperative recovery with instantaneous vision restoration. These patients are generally awake, alert, and retain their protective reflexes.

A comparison of patient-controlled analgesia fentanyl and alfentanil for labour analgesia

PURPOSE

To determine the analgesic efficacy of equipotent doses of PCA (patient-controlled analgesia) fentanyl and PCA alfentanil for labour pain.

METHODS

Twenty three, ASA I - II parturients between 32-42 wk gestational age in whom epidural analgesia was contraindicated were randomized to receive PCA fentanyl (Group F)or alfentanil (Group A). Plain numbered vials contained 21 ml fentanyl 50 microg x ml(-1) or alfentanil 500 microg x ml(-1). A one millilitre loading dose was administered. The PCA solution was prepared by diluting 10 ml study drug with 40 ml saline and the PCA pump was programmed to deliver a dose of 2 ml, delay of five minutes and a basal rate of 2 ml x hr(-1). Maternal measurements obtained were hourly drug dose, total dose, Visual Analog Pain Score (VAPS) q 30 min, sedation score q 1 hr and side effects. Neonates were assessed by 1,5, and 10-min Apgar scores, umbilical venous and arterial blood gases and neurobehavioural scores at four and 24 hr.

RESULTS

Mean VAPS from 7 - 10 cm cervical dilatation were higher in Group A than in Group F (85.7+/-13.9 vs. 64.6+/-12.1; P<0.01) There were no inter-group differences in VAPS from 1-3 cm, or from 4-6 cm dilatation, in maternal sedation scores or side effects, or in neonatal outcomes.

CONCLUSION

In the doses prescribed in this study, PCA fentanyl was found to provide more effective analgesia in late first stage labour than PCA alfentanil.

Propofol anesthesia for craniotomy: a double-blind comparison of remifentanil, alfentanil, and fentanyl

For patients undergoing craniotomy, it is desirable to have stable and easily controllable hemodynamics during intense surgical stimulation. However, rapid postoperative recovery is essential to assess neurologic function. Remifentanil, an ultra-short-acting mu-opioid receptor agonist, may be the ideal agent to confer the above characteristics. In this prospective randomized study, we compared the hemodynamic stability, recovery characteristics, and the dose of propofol required for maintaining anesthesia supplemented with an infusion of remifentanil, alfentanil, or fentanyl in 34 patients scheduled for supratentorial craniotomy. With routine monitors in place, anesthesia was induced with propofol (2-3 mg/kg), atracurium (0.5 mg/kg), and either remifentanil (1 microg/kg), alfentanil (10 microg/kg), or fentanyl (2 micro/kg). The lungs were ventilated with O2/air to mild hypocapnia. Anesthesia was maintained with infusions of propofol (50-100 microg/kg/min) and either remifentanil (0.2 microg/kg/min), alfentanil (20 microg/kg/h), or fentanyl (2 microg/kg/h). There were no significant differences among the groups in the dose of propofol maintenance required, heart rate, or mean arterial pressure. However, the time to eye opening (minutes) was significantly shorter in the remifentanil compared to the alfentanil group (6+/-3; 21+/-14; P = 0.0027) but not the fentanyl group (15+/-9). We conclude that remifentanil is an appropriate opioid to use in combination with propofol during anesthesia for supratentorial craniotomy.

The cost-effectiveness of methohexital versus propofol for sedation during monitored anesthesia care

We designed this study to test the hypothesis that methohexital is a cost-effective alternative to propofol for sedation during local anesthesia. Sixty consenting women undergoing breast biopsy procedures under local anesthesia were randomly assigned to receive an infusion of either propofol (50 microg x kg(-1) x min(-1)) or methohexital (40 microg x kg(-1) x min(-1)). The sedative infusion rate was titrated to maintain an observer's assessment of alertness/sedation (OAA/S) score of 3 (with 1 = awake/alert to 5 = asleep). Fentanyl 25 microg i.v. was administered as a "rescue" analgesic during the operation. We assessed the level of sedation (OAA/S score), vital signs, time to achieve an OAA/S score of 3 at the onset and a score of 1 after discontinuing the infusion, discharge times, perioperative side effects, and patient satisfaction. The direct cost of methohexital was lower than that of propofol, based on the milligram dosage infused during the operation. The sedative onset (to achieve an OAA/S score of 3) and the recovery (to return to an OAA/S score of 1) times, as well as discharge times, did not differ between the two groups. Patients receiving methohexital had a significantly lower incidence of pain on initial injection compared with those receiving propofol (10% vs 23%). Because the use of methohexital (29.4 +/- 2.7 microg x kg(-1) x min(-1)) for sedation during breast biopsy procedures has a similar efficacy and recovery profile to that of propofol (36.8 +/- 15.9 microg x kg(-1) x min(-1)) and is less costly based on the amount infused, it seems to be a cost-effective alternative to propofol for sedation during local anesthesia. However, when the cost of the drug infused and drug wasted was calculated, there was no difference in the overall drug cost.

IMPLICATIONS

When administered to maintain a stable level of sedation during local anesthesia, methohexital is an acceptable alternative to propofol. However, the overall drug costs were similar with the two drugs.

Middle latency auditory evoked potentials during total intravenous anesthesia with droperidol, ketamine and fentanyl

We investigated whether total intravenous anesthesia with ketamine, fentanyl and droperidol would affect middle latency auditory evoked potentials and explicit memory, and whether dreams during the anesthesia are related to plasma concentrations of fentanyl and the infusion technique. A total number of 40 patients were the subjects for this study. Twenty patients (group A) were maintained with intravenous ketamine 2 mg kg-1 hr-1 and fentanyl 5 micrograms kg-1 hr-1 for the first 60 min and 3 micrograms kg-1 hr-1 for the next 90 min, and droperidol 0.1 mg kg-1. The remaining 20 patients (group B) were maintained with intravenous ketamine 2 mg kg-1 hr-1, droperidol 0.1 mg kg-1 and fentanyl 50-100 micrograms in a bolus intermittently as needed by vital signs such as increases in heart rate and arterial blood pressure. Middle latency auditory evoked potentials, plasma fentanyl and ketamine levels were measured; explicit memory and dreams were also estimated. There were no patients who recollected explicit memories of intraoperative events in both groups. The middle latency auditory evoked potentials were not significantly changed during the anesthesia in both groups. We could find no significant differences in latencies and amplitudes of the middle latency auditory evoked potentials between the both groups. Plasma fentanyl levels of group B patients were significantly lower than those of group A patients and the incidence of the dreams was significantly higher in group B patients. We conclude that the anesthesia with ketamine, fentanyl and droperidol is not associated with the explicit memories, though the middle latency auditory evoked potentials were not significantly changed as compared with those in the waking state. In addition, dreams during the anesthesia may correlate with plasma fentanyl concentrations or the infusion technique.

Remifentanil administration during monitored anesthesia care: are intermittent boluses an effective alternative to a continuous infusion?

This randomized, double-blind study was designed to evaluate the analgesic effectiveness and respiratory stability of remifentanil when administered as intermittent bolus injections, a variable-rate infusion, or a combination of a constant basal infusion supplemented with intermittent boluses during monitored anesthesia care (MAC). Forty-five patients undergoing extracorporeal shock wave lithotripsy (ESWL) procedures were randomly assigned to one of the three modes of remifentanil administration. All patients received midazolam 2 mg i.v., followed by a propofol infusion at 50 microg x kg(-1) x min(-1). Two minutes before administering a series of test shock waves: Group I received a remifentanil infusion of 0.1 microg x kg(-1) x min(-1), and a saline bolus (5 mL); Group II received a saline infusion and a remifentanil bolus (25 microg in 5 mL); and Group III received a remifentanil infusion of 0.05 microg x kg(-1) x min(-1), and a remifentanil bolus (12.5 microg in 5 mL). The average pain intensity was scored on an 11-point scale, with 0 = no pain to 10 = severe pain. During the ESWL procedure, pain was treated by increasing the study drug infusion rate by 25%-50% and administering 5-mL bolus injections of the study medication in Groups I (saline) and II (remifentanil 25 microg). In Group III, intermittent 5-mL boluses (remifentanil 12.5 microg) were administered as needed. Patients in Groups II and III reported lower pain scores in response to the test shocks. Significantly more remifentanil was administered in Group I (379 +/- 207 microg) than in Group II (201 +/- 136 microg). However, more interventions were required for the treatment of intraoperative pain in the intermittent bolus group (Group II). When remifentanil is administered as the analgesic component of a MAC technique, these data support the use of intermittent bolus doses (12.5-25 microg) alone or in combination with a basal infusion (0.05 microg x kg(-1) x min(-1)) as alternatives to a variable-rate continuous infusion.

IMPLICATIONS

In this study, three different modes of remifentanil administration were used during monitored anesthesia care for extracorporeal shock wave lithotripsy procedures. These results suggest that using intermittent bolus injections of remifentanil (25 microg) or a continuous infusion (0.05 microg x kg(-1) x min(-1)) supplemented with intermittent bolus (12.5 microg) injections may be more effective than a variable-rate infusion of remifentanil during propofol sedation.

What is new in monitored anesthesia care?

The use of monitored anesthesia care (MAC) techniques is increasing in popularity because recovery profiles seem to be improved compared with general and regional anesthesia. This article describes the conceptual basis for MAC and reviews the current MAC practices.

Comparison of desflurane with isoflurane or propofol in spontaneously breathing ambulatory patients

Desflurane is a potentially useful anesthetic for ambulatory surgery, but it has had limited evaluation in spontaneously breathing patients. After the induction of anesthesia with propofol and laryngeal mask insertion, 90 patients were randomized to receive isoflurane (0.25%-1%), propofol (50-200 microg x kg(-1) x min(-1)), or desflurane (1.4%-6%) for anesthetic maintenance. Respiratory complications were uncommon; only six patients coughed (three who received isoflurane, one who received propofol, and two who received desflurane), and no anesthetic produced significant respiratory depression. Purposeful movement was significantly more common with propofol (19 patients; 63%) compared with isoflurane (7 patients; 23%) or desflurane (2 patients; 6.7%), but no patient had recall. Emergence times were similar in the isoflurane, propofol, and desflurane groups (5.1 +/- 2.3, 5.6 +/- 3.1, and 4.4 +/- 1.4 min, respectively). Later recovery end points and pain and sedation visual analog scale scores did not differ among groups. Overall, 85 patients (94%) were free from postoperative nausea and vomiting. Desflurane produced few respiratory complications in spontaneously breathing ambulatory patients but offered no improvement in emergence or recovery compared with isoflurane. Propofol also did not reduce recovery times or side effects; however, it was more difficult to maintain an adequate depth of anesthesia. We conclude that neither desflurane nor propofol offered any major advantages over the older anesthetic, isoflurane, under the conditions of our study.

IMPLICATIONS

The new inhaled anesthetic desflurane is acceptable in spontaneously breathing outpatients despite its known ability to irritate the airway. The i.v. anesthetic propofol was associated with more patient movement (without awareness) during surgery. Neither anesthetic conferred any clinically significant advantages over the older inhaled drug, isoflurane.

Complications of sedation with midazolam in the intensive care unit and a comparison with other sedative regimens

OBJECTIVE

To describe the various complications that have been reported with use of midazolam for sedation in the intensive care unit (ICU).

DATA SOURCES

Publications in scientific literature.

DATA EXTRACTION

Computer search of the literature.

SYNTHESIS

Sedation is required in the ICU in order for patients to tolerate noxious stimuli, particularly mechanical ventilation. Under- and oversedation can lead to complications. To sedate patients in the ICU, midazolam is commonly administered via titrated, continuous infusions. Cardiorespiratory effects tend to be minimal; however, hypotension can occur in hypovolemic patients. Prolonged sedation after cessation of the midazolam infusion may be caused by altered kinetics of the drug in critically ill patients or by accumulation of active metabolites. In addition, paradoxical and psychotic reactions have been rarely reported. Tolerance and tachyphylaxis may occur, particularly with longer-term infusions (> or = 3 days). Benzodiazepine withdrawal syndrome has also been associated with high dose/long-term midazolam infusions. Compared with propofol infusions, midazolam infusions have been associated with a decreased occurrence of hypotension but a more variable time course for recovery of function after the cessation of the infusion. Lorazepam is a more cost-effective choice for long-term (> 24 hrs) sedation.

CONCLUSION

Continuous infusion midazolam provides effective sedation in the ICU with few complications overall, especially when the dose is titrated.

Continuous fentanyl infusion: use in severe cancer pain

OBJECTIVE

To describe the use of a continuous fentanyl infusion in an adult cancer patient.

CASE SUMMARY

A 66-year-old white woman diagnosed with metastatic pancreatic carcinoma required hospital admission for pain control after receiving five different chemotherapy regimens. Morphine 2 mg/h i.v. was initiated and the dosage was titrated upward to a total of 6613 mg/d by hospital day 16. As hospital supplies of opioids became depleted over a holiday weekend, therapy was changed to a continuous infusion of hydromorphone 70 mg/h on hospital day 17, then changed to a continuous fentanyl infusion beginning with a dosage of 500 micrograms/h. The fentanyl dosage was titrated to 4250 micrograms/h by hospital day 20. She died comfortably on hospital day 22 while receiving this dosage.

DISCUSSION

Continuous infusions of opioids, particularly morphine and hydromorphone, are frequently used for control of cancer pain and are safe and effective when administered by this route. Transdermal fentanyl has been shown to effectively manage chronic cancer pain, and use of continuous subcutaneous fentanyl has been reported. However, reports of continuous intravenous fentanyl infusion in the cancer pain literature are limited. Our patient achieved good pain control with a continuous infusion of fentanyl 4250 micrograms/h.

CONCLUSIONS

Continuous fentanyl infusion should be considered for the treatment of cancer pain in patients requiring high doses who become refractory to other opioids, when other opioids cause intolerable adverse effects, when patients have a true morphine allergy, or when high-dose requirements threaten to deplete existing stock of alternate opioids.

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.

Survey of postoperative analgesia following ambulatory surgery

BACKGROUND

The quality of pain relief during the first 48 hours following ambulatory surgery has been poorly documented. This questionnaire study was performed to evaluate the nature and severity of pain after the patient leaves the hospital.

METHODS

1100 patients in the age group 5-88 years who underwent ambulatory surgery during a period of 6 months were asked to complete a questionnaire 48 h after the end of the operation. In the case of children, parents were asked to complete a similar questionnaire. The questions were related to pain experienced during the first 48 h after surgery and to the nature and severity of postoperative complications.

RESULTS

A total of 1035 out of the 1100 patients returned the questionnaire, 94.1%. Overall the majority (65%) of patients had only mild pain at home; however, patients undergoing certain types of surgery had moderate-to-severe pain: inguinal hernia surgery (62% patients), orthopaedic surgery (41%), hand surgery (37%) and varicose vein surgery (36%). In these patients the severity of pain did not decrease during the 2-day study period. About 10% patients had more severe pain than they had anticipated, and 20% had difficulty in sleeping at night due to severe pain. Despite this, over 95% of patients were satisfied with management of postoperative pain. Nausea (20%), tiredness (20%) and vomiting (8%) were the commonest complications reported during the first 48 h. A significant association was found between the administration of a general anaesthetic and the incidence of nausea postoperatively. A large number of patients were alone at home after the operation (28.4%); some (3.8%) had no access to a relative or friend in case of need.

CONCLUSION

Our results show that about 35% of day-surgery patients experience moderate-to-severe pain at home in spite of analgesic medication. About 20% of patients had sleep problems due to severe pain. However, only 5% of patients were dissatisfied. Better analgesic techniques are necessary for patients undergoing certain types of surgery. Patient information and follow-up routines need to be improved.

Acupressure treatment for prevention of postoperative nausea and vomiting

Postoperative nausea and vomiting are still common problems after general anesthesia, especially in ambulatory surgery. Drug therapy is often complicated with central nervous system symptoms. We studied a nonpharmacological method of therapy--acupressure--at the Pericardium 6 (P.6) (Nei-Guan) meridian point. Two hundred consecutive healthy patients undergoing a variety of short surgical procedures were included in a randomized, double-blind study: 108 patients were in the acupressure group (Group 1) and 92 patients were in the control group (Group 2). Spherical beads of acupressure bands were placed at the P.6 points in the anterior surface of both forearms in Group 1 patients, while in Group 2 they were placed inappropriately on the posterior surface. The acupressure bands were placed before induction of anesthesia and were removed 6 h postoperatively. They were covered with a soft cotton wrapping to conceal them from the blinded observer who evaluated the patients for presence of nausea and vomiting and checked the order sheet for any antiemetics prescribed. In both groups, the age, gender, height, weight, and type and duration of surgical procedures were all comparable without significant statistical difference. In Group 1, only 25 of 108 patients (23%) had nausea and vomiting as compared to Group 2, in which 38 of 92 patients (41%) had nausea and vomiting (P = 0.0058). We concluded that acupressure at the P.6 (Nei-Guan) point is an effective prophylaxis for postsurgical nausea and vomiting and therefore a good alternative to conventional antiemetic treatment.

Total intravenous anesthesia and high-frequency jet ventilation during transthoracic endoscopic sympathectomy for treatment of essential hyperhidrosis palmaris: a new approach

OBJECTIVE

To evaluate the effects of high-frequency jet ventilation (HFJV) applied to both lungs on hemodynamic parameters, oxygenation, and operating conditions during bilateral videothoracoscopic sympathectomy.

DESIGN

A prospective, unblinded study.

SETTING

An ambulatory surgical unit at a university medical center.

PARTICIPANTS

30 patients (11 men, 19 women), ASA status 1.

INTERVENTION

Bilateral videothoracoscopic sympathectomies were performed using total intravenous anesthesia with propofol, alfentanil, and atracurium, and the patients were ventilated with an oxygen-air mixture using HFJV delivered to both lungs with a Hi-Lo Jet tracheal tube (Mallinckrodt).

MEASUREMENTS AND MAIN RESULTS

Mean total anesthesia time was 55 +/- 13 minutes. Hemodynamic parameters remained stable during surgery, although ablation of the sympathetic ganglia induced three incidences of bradycardia (10% of the patients), which were responsive to atropine. Four patients developed oxygen desaturation (Sa O2 < 90%) after the creation of the pneumothorax. Surgical conditions were considered excellent by the surgeons. Concerning postoperative complications, a temporary Horner's syndrome was observed in one patient. Another patient had a mild residual pneumothorax on the first postoperative day that resolved without insertion of a chest tube.

CONCLUSIONS

It was concluded that HFJV applied to both lungs is an easy and safe anesthetic technique that provides excellent surgical conditions and causes a minor incidence of morbidity.

Patient maintained alfentanil target-controlled infusion for analgesia during extracorporeal shock wave lithotripsy

PURPOSE

The purpose of this study was to determine whether alfentanil given by a pharmacokinetic-based target controlled infusion (TCI) system under patient control is a suitable analgesic technique for extracorporeal shock wave lithotripsy (ESWL).

METHODS

The design was an open, unblinded, noncomparative, prospective study. Forty outpatients undergoing ESWL were given patient maintained alfentanil TCI. Pain, nausea and sedation were assessed every 300 shocks. Vital signs were recorded every three minutes, pulse oximetry and electrocardiography being monitored continuously. Blood alfentanil concentration was measured for comparison with the predicted value.

RESULTS

Alfentanil consumption (median 1.34 mg, range 0.8-3.6) and measured levels following treatment (median 60 ng.ml-1, range 15.6-134.3) varied widely. The precision of the TCI system and the median prediction error (bias) were both 49%. The median of pain scores recorded during treatment was 4 (range 0-8). The median respiration rate was 15 bpm (range 10-23), three patients required oxygen (SaO2 < 92%) cardiovascular measurements were stable and there was no excessive sedation. The incidence of nausea was 15%. All patients were ready for hospital discharge within one hour following treatment.

CONCLUSIONS

Patient maintained alfentanil TCI provides good analgesia for ESWL in the majority of patients with little sedation. Respiratory depression is uncommon but supplementary oxygen should be given prophylactically. There is considerable interindividual variation in demand for alfentanil indicating the usefulness of the patient control method. The TCI system underestimated alfentanil blood concentrations but this did not affect its clinical usefulness.

Incidence of nausea and vomiting in outpatients undergoing general anesthesia in relation to selection of intraoperative opioid

STUDY OBJECTIVE

To measure the incidence of nausea and vomiting in outpatients in relation to selection of, or withholding of, intraoperative opioid.

DESIGN

Prospective, randomized, double-blind control trial.

SETTING

University general hospital.

PATIENTS

200 unpremedicated ASA status 1 and 11 patients, 8 to 80 years old, undergoing general anesthesia for ambulatory surgery.

INTERVENTION

Patients were randomized to four groups, three of which received equipotent doses of different opioids intravenously (i.v.) during induction of anesthesia. Group 1 received nalbuphine 0.25 mg/kg, Group 2, alfentanil 20 ug/kg; Group 3, fentanyl 2 ug/kg; and Group 4, normal saline.

MEASUREMENTS AND MAIN RESULTS

We evaluated (1) incidence and severity of nausea and vomiting in the postanesthesia care unit (PACU) and over the next 24 hours; (2) time to PACU discharge; (3) need for antiemetic therapy; and (4) need for analgesic rescue in the PACU. The incidences of nausea and vomiting were similar in all groups, as were time to discharge, antiemetic, and nonsteroidal antiinflammatory drug requirements. The highest incidences of nausea and vomiting occurred at 6 hours in all groups (23% and 9.5%, respectively). Group 1 required lower rescue doses of morphine in the PACU but this result may have been an artifact due to employing the mixed agonist-antagonist opioid, nalbuphine, in this group.

CONCLUSIONS

Opioid administration at the doses employed during induction of anesthesia does not promote postoperative nausea or vomiting, nor increase length of stay in the PACU.

Patient-controlled alfentanil. Target-controlled infusion for postoperative analgesia

We have compared the opioid effects of a patient-demand, target-controlled infusion of alfentanil (n = 10), with patient-controlled bolus administration of morphine (n = 10) following major spinal surgery in Chinese patients aged from 11 to 67 years. The same general anaesthesia regimen was used in all patients. One group of patients were given intra-operative morphine analgesia followed by postoperative intravenous morphine patient-controlled analgesia, while the other group received an intra-operative target-controlled infusion of alfentanil. Following surgery, the alfentanil group were given control of a handset and were able to increase the target alfentanil plasma level in 5 ng.ml-1 increments with a 2-min lockout interval. If analgesia was not demanded within a 15-min period, the computer reduced the target concentration by 5 ng.ml-1. All patients had continuous pulse oximetry monitoring and hourly recording of pain, sedation, nausea scores and respiratory rate. Patients receiving alfentanil had the target concentration noted hourly and four blood samples taken during the first 24 h for measurement of plasma alfentanil concentrations by high performance liquid chromatography. The alfentanil infusion system was equally effective as an analgesic technique when compared with morphine patient-controlled analgesia. There were no hypoxaemic episodes (oxygen saturation < 94%), no difference in sedation scores and the incidence of nausea (30%) was the same in both groups. There was a significantly (p < 0.001) lower respiratory rate in the alfentanil group compared with patients receiving morphine at, clinically assessed, equianalgesia. The predicted plasma alfentanil concentrations increased rapidly from about 30 ng.ml-1 during the first 4 h to around 100 ng.ml-1 at the end of the 24-h study period. The precision of the target-controlled infusion system was 75.4% and the mean prediction error (bias) 58.1%, suggesting an underestimation of the measured alfentanil concentrations by the alfentanil infusion system in these Chinese patients.

Alfentanil modifies the neurocirculatory responses to desflurane

Activation of the sympathetic nervous system occurs in response to desflurane, causing tachycardia and hypertension. Fentanyl partially blunts the hemodynamic effects of desflurane but fails to attenuate the sympathetic response. This study determined the clinical effectiveness and dose response of alfentanil on the neurocirculatory responses to desflurane. Twenty-five healthy, male volunteers were randomized into one of three groups to receive either placebo (n = 9), 10 micrograms/kg intravenous (IV) bolus alfentanil (n = 9), or 20 micrograms/kg IV bolus alfentanil (n = 7) in conjunction with anesthetic induction by propofol, 2.5 mg/kg. Mean arterial pressure (MAP, radial artery), heart rate (HR), and efferent muscle sympathetic nerve activity (SNA, peroneal nerve) were recorded. After conscious baseline measurements, anesthesia was induced by propofol and alfentanil/placebo. One minute later, the desflurane vaporizer was activated at 11%. Neurocirculatory measurements were recorded for 11 min. There were no differences between the groups at conscious baseline. Induction of anesthesia was associated with significantly decreased MAP in the placebo and the 10 micrograms/kg alfentanil groups and increased HR in all groups with little change in SNA. In placebo subjects, desflurane administration increased HR and MAP above baseline. In both alfentanil groups, during desflurane administration HR and MAP never increased significantly above baseline. However, SNA was significantly increased in both groups. Alfentanil effectively blunts the hemodynamic changes but not the sympathetic responses associated with rapid increases in the inspired concentration of desflurane.