Comparison of hemodynamics, recovery profile, and early postoperative pain control and costs of remifentanil versus alfentanil-based total intravenous anesthesia (TIVA)

Remimazolam-remifentanil causes less postoperative nausea and vomiting than remimazolam-alfentanil during hysteroscopy: a single-centre randomized controlled trial

BACKGROUND

Although the operation time of hysteroscopy is short, the incidence of postoperative nausea and vomiting is high. The aim of this study was to compare the incidence of postoperative nausea and vomiting in hysteroscopy when remimazolam is combined with remifentanil or alfentanil.

METHODS

We conducted a randomized, controlled, double-blind trial. Patients undergoing hysteroscopy were recruited and randomly assigned to either the remimazolam-remifentanil (Group RR) or the remimazolam-alfentanil group (Group RA). All patients in the two groups were started with an induction dose of remimazolam besylate 0.2 mg/kg and then maintained with a dosage of 1.0 mg/kg/h. After induction with remimazolam besylate, in Group RR, remifentanil was infused using a target-controlled infusion system with a target concentration of 1.5 ng/ml and titrated throughout the procedure. In Group RA, infusion of alfentanil was started with an initial bolus dose of 20 µg/kg over 30 s and then maintained at an initial rate of 0.16 µg/kg/min. The primary observation outcome was the incidence rate of postoperative nausea and vomiting. The secondary observation outcomes were the time to awakening, the length of stay in the PACU, the total remimazolam dose and adverse effects, such as low SpO2, bradycardia, hypotension and body movement.

RESULTS

A total of 204 patients were successfully included in this study. The incidence of postoperative nausea and vomiting in Group RR (2/102, 2.0%) was significantly lower than that in Group RA (12/102, 11.8%) (p < 0.05). There was no significant difference in the incidence of adverse events, such as low SpO2, bradycardia, hypotension and body movement, between Groups RR and RA (p > 0.05).

CONCLUSIONS

Remimazolam-remifentanil causes less postoperative nausea and vomiting than remimazolam-alfentanil in hysteroscopy.

TRIAL REGISTRATION

Clinical trial registration number: ChiCTR2100044177. Full date of the first registration: 12/03/2021.

The Effect of Different Doses of Isoflurane on Hemodynamic Changes and Bleeding in Patients Undergoing Endoscopic Sinus Surgery under General Anesthesia

Background

Nowadays, endoscopic sinus surgery is one of the most common surgeries in the field of ear, nose, and throat. This surgery has always been followed by bleeding and can cause hemodynamic disorders due to the direct effect of the endoscopic sinus surgery.

Objectives

This study aimed to investigate the hemodynamic changes with different doses of isoflurane during endoscopic sinus surgery.

Methods

In a randomized clinical trial, 90 patients were selected based on ASA class I and II, and divided into three groups of 30 people. The method of anesthesia induction in groups was alike. After induction anesthesia, isoflurane with percentages of 1%, 1.2%, and 1.5% was used in the groups of 1, 2, and 3, respectively and remifentanil was fixed and used in the groups in a dose of 0.1 g/kg/min during the surgery.

Results

There was a significant difference in changes in mean of arterial pressure (MAP) after induction in the 3 groups (P < 0.001) that the reduction in mean of arterial pressure between 1 and 3 groups and between 2 and 3 groups were significantly different. There was a significant difference in heart rate per 30, 45, and 60 minutes between 1 and 2 groups (P < 0.001).

Conclusions

Isoflurane percentages of 1.5% versus 1.2% and 1% affected generally a considerable reduction rate of 1% in bleeding and better control of mean arterial blood pressure. In addition, the mean heart rate in several minutes in group 2 with 1.2% isoflurane was less than other groups.

Inguinal hernia repair in day surgery: the role of MAC (Monitored Anesthesia Care) with remifentanil

BACKGROUND

The extension of indications for procedures in a Day Surgery (DS) setting has led to changes in the anesthetic and surgical treatment of Inguinal Hernias (IH). According to the recommendations of the European Hernia Society, the treatment of IH in DS units should be performed under Monitored Anesthesia Care (MAC).

PATIENTS AND METHODS

960 patients underwent IH repairs over a period of 24 months. The patients were randomly divided into two groups: R (remifentanil) and F (fentanyl); the group F was considered as a control group. The exclusion criteria in both group were: morbid obesity (BMI>40 or BMI>35 in association with high blood pressure or diabetes); coagulopathy; OSAS (obstructive sleep apnea syndrome) with AHI >10; cardiovascular, respiratory, renal, hepatic or metabolic disease; history of substances abuse; GERD-related esophagitis (gastro-esophageal reflux disease); chronic analgesic use; allergy to local anesthetic and ASA>III. Patients reported their level of pain on a verbal numeric scale (VNS), with scores ranging from 0 to 10. For each patient systolic and diastolic blood pressure (SBP and DBP), mean arterial pressure (MAP), heart rate (HR) and peripheral oxygen saturation (SpO2) were recorded. The results are presented as the mean value ± standard deviations; statistical analysis was performed using Student's t-test.

RESULTS

Amongst the 960 procedures, complications or side effects related to the anesthetic techniques didn't occur; no procedure-related complications requiring mechanical ventilation support were reported. Our research focused on evaluating remifentanil effectiveness in pain control and its impact on hemodynamic stability and respiratory function. There was a significant difference between the two groups with regard to the VNS.

CONCLUSIONS

Remifentanil, is an excellent drug for pain control during intra-operative procedures, that allows an optimal hemodynamic stability for IH repairs in a DS setting, due to its pharmacokinetic and pharmacodynamic properties and few adverse effects.

Total intravenous anesthesia produces outcomes superior to those with combined intravenous-inhalation anesthesia for laparoscopic gynecological surgery at high altitude

Objective We compared efficacy and adverse outcomes following totally intravenous anesthesia (TIVA) versus combined intravenous-inhalation anesthesia (CIVIA) on hemodynamics and postoperative recovery following laparoscopic gynecological (LG) surgery at high altitudes. Methods We enrolled 80 ASA I or II patients scheduled for LG surgery and randomly assigned them to TIVA with propofol (group P, n = 40) or CIVIA with isoflurane (group I, n = 40). Mean arterial pressure, heart rate, pulse oxygen saturation, and partial pressure of end-tidal carbon dioxide were measured at various time points. Outcome measures were interval to spontaneous ventilation, eye opening, return to consciousness, extubation, operating room duration. Intraoperative awareness and postoperative nausea/vomiting were assessed at follow-up. Results No differences in hemodynamic parameters were detected in either group. Group P had a significantly shorter postoperative anesthetic recovery time and lower incidence of postoperative nausea/vomiting. Conclusion TIVA is superior to CIVIA for GL surgery at high altitudes.

Perioperative Effects of Different Narcotic Analgesics Used to Improve Effectiveness of Total Intravenous Anaesthesia

OBJECTIVE

We aimed to evaluate the depth of anaesthesia, perioperative haemodynamics, postoperative pain scores, analgesic consumption in patients receiving remifentanil- or alfentanil-based total intravenous anaesthesia for single-level lumbar discectomy.

METHODS

Seventy patients undergoing discectomy were enrolled in the study. Patients were intravenously administered an initial bolus dose of 2 mg kg(-1) propofol and 10 mcg kg(-1) alfentanil or 1 mcg kg(-1) remifentanil, followed by 6 mg kg(-1) h(-1) propofol and either 1 mcg kg(-1) min(-1) alfentanil or 0.25 mcg kg(-1) min(-1) remifentanil infusion. Bispectral index (BIS) values, mean arterial pressure, heart rate, end-tidal carbon dioxide and oxygen saturation were recorded. Postoperative pain scores at 0, 30 and 60 min were measured and recorded with additional opioid requirements.

RESULTS

Postoperative pain scores at 0 and 30 min, total analgesic consumption and requirement for additional analgesics were significantly high in the remifentanil group. After the first hour, the pain scores were not significantly different. Mean arterial blood pressure was significantly low at 45 and 60 min preoperatively in the remifentanil group. In the remifentanil group, heart rate at 15, 30, 45, 60 min were significantly lower than those in the alfentanil group. BIS values of the two groups were not significantly different at any measurement time point. BIS values of remifentanil group at 30, 45, 60, 90 and 180 min significantly increased compared with those at 15 min.

CONCLUSION

Alfentanil provided more stable BIS and haemodynamic values preoperatively and less opioid consumption, along with lower pain scores, during the early postoperative period compared with remifentanil in patients undergoing single-level discectomy.

Randomized double-blind comparison of remifentanil and alfentanil in patients undergoing laparoscopic cholecystectomy using total intravenous anesthesia

BACKGROUND AND AIMS

To compare the use of remifentanil and alfentanil to suppress intraoperative adrenergic response of pain and the influence of these drugs on the recovery profile in patients undergoing laparoscopic cholecystectomy using a total intravenous anesthesia (TIVA) technique.

MATERIAL AND METHODS

One hundred patients undergoing elective laparoscopic cholecystectomy were randomized to be managed with either remifentanil (group R) or alfentanil (group A). During general anesthesia, we evaluated adrenergic responses to intubation to first surgical incision and over the surgical procedure. We also recorded time to first spontaneous breathing, time to successful ventilation, time to respond to verbal orders, and time to extubation.

RESULTS

The R group reported a significantly lower number of responses to intubation and responses to first surgical incision (14% vs. 30%; P = 0.013 and 8% vs. 18%; P = 0,037, respectively). The event of one or more responses during the surgical procedure was also lower in the R group (56% vs. 70%; P = 0.017). Hypertensive response to surgical stimuli during the procedure was lower in the R group as well as a lower frequency of tachycardia episodes in this group (34% vs. 56%; P = 0.033 and 28% vs. 44%; P = 0.041, respectively). No differences were found between groups relating to the percentage of hypotensive episodes and no episodes of bradycardia were appreciated. Both groups were similar relating to recovery times: time to the first spontaneous breathing, time to successful ventilation, time to respond to verbal orders, and time to extubation.

CONCLUSION

Remifentanil showed a more stable hemodynamic response during the surgery compared with the use of alfentanil in anesthetized patients undergoing laparoscopic cholecystectomy using TIVA. Both opioids, alfentanil and remifentanil, have a similar recovery profile, and they do not delay time to awakening.

Improving patient safety after rigid bronchoscopy in adults: laryngeal mask airway versus face mask - a pilot study

Background

There are still no clear guidelines in the literature on per procedural bronchoscopic management for anesthesiologists, and few relevant datasets are available. To obtain rapid recovery from anesthesia, it is often necessary to keep patients in the recovery room for several hours until they become clinically stable. In this study, we tested the hypothesis that the laryngeal mask airway (LMA) enables better respiratory and hemodynamic recovery than the oxygen face mask (FM) in patients undergoing rigid bronchoscopy.

Methods

Twenty-one patients undergoing elective bronchoscopy of the upper airway were randomized to ventilation assistance with FM or LMA after a rigid bronchoscopy procedure under general anesthesia. The primary endpoint was duration of post-surgical recovery and the secondary endpoints were postoperative hemodynamic and respiratory parameters. Assessment of the study endpoints was performed by an intensive care specialist blinded to the method of ventilation used. The statistical analysis was performed using the Fisher’s Exact test for nominal data and the Student’s t-test for continuous data.

Results

There was no statistically significant difference in post-procedural time between the two groups (P=0.972). The recovery parameters were significantly better in the LMA group than in the FM group, with significantly fewer desaturation, hypotensive, and bradycardic events (P<0.05).

Conclusion

We conclude that the LMA may be safer and more comfortable than the FM in patients undergoing rigid bronchoscopy.

Pharmacokinetics and pharmacodynamics of propofol in cancer patients undergoing major lung surgery

Despite the growing number of cancer cases and cancer surgeries around the world, the pharmacokinetics (PK) and pharmacodynamics (PD) of anesthetics used in this population are poorly understood. Patients operated due to cancer are usually in severe state and often require chemotherapy. It might affect the PK/PD of drugs used in this population. Therefore, in this study we explored the PK/PD of propofol in cancer patients having a major lung surgery. 23 patients that underwent a propofol-fentanyl total intravenous anesthesia were included in the analysis. A large set of demographic, biochemical and hemodynamic parameters was collected for the purpose of covariate analysis. Nonlinear mixed effect modeling in NONMEM was used to analyze the collected data. A three-compartment model was sufficient to describe PK of propofol. The anesthetic effect (AAI index) was linked to the propofol effect site concentrations through a sigmoidal E max model. A slightly higher value of clearance, a lower value of distribution clearance, and a decreased volume of peripheral compartment were observed in our patients, as compared with the literature values reported for healthy volunteers by Schnider et al. and by Eleveld et al. Despite these differences, both models led to a clinically insignificant bias of -8 and -1 % in concentration predictions, as reflected by the median performance error. The C e50 and propofol biophase concentration at the time of postoperative orientation were low and equaled 1.40 and 1.13 mg/L. The population PK/PD model was proposed for cancer patients undergoing a major lung surgery. The large body of studied covariates did not affect PK/PD of propofol significantly. The modification of propofol dosage in the group of patients under study is not necessary when TCI-guided administration of propofol by means of the Schnider model is used.

Considerations for the use of short-acting opioids in general anesthesia

Anesthesiologists play a critical role in facilitating a positive perioperative experience and early recovery for patients. Depending on the kind of procedure or surgery, a wide variety of agents and techniques are currently available to anesthesiologists to administer safe and efficacious anesthesia. Notably, the fast-track or ambulatory surgery environment requires the use of agents that enable rapid induction, maintenance, and emergence combined with minimal adverse effects. Short-acting opioids demonstrate a safe and rapid onset/offset of effect; that short effect is both predictable and precise. It also ensures easier titration and reduced or rapidly reversed side effects. Due to their distinct pharmacokinetic and pharmacodynamic properties, and, in one case, rapid extra-hepatic clearance of remifentanil, these agents have several applications in general anesthesia.

Prevention of perioperative and anesthesia-related complications in facial cosmetic surgery

Although office-based anesthesia for facial cosmetic surgery remains remarkably safe, no anesthesia or sedation performed outside the operating room should be considered minor. Proper organization, preparation, and patient selection, close collaboration with the surgeon, and expert and effective anesthesia care will increase patient safety and improve perioperative outcomes and patient satisfaction. This article presents a comprehensive overview of anesthesia in terms of facial plastic surgery procedures, beginning with a broad review of essentials and pitfalls of anesthesia, followed by details of specific anesthetic agents, their administration, mechanism of action, and complications.

Postoperative nausea and vomiting after endoscopic thyroidectomy: total intravenous vs. balanced anesthesia

BACKGROUND

Endoscopic thyroidectomy was recently introduced and has been rapidly accepted by surgeons and patients. The present study was conducted to estimate and compare the incidences of postoperative nausea and vomiting (PONV) after endoscopic thyroidectomy using two different anesthetic methods: sevoflurane based balanced anesthesia; total intravenous anesthesia (TIVA).

METHODS

Ninety nine female patients that were scheduled to undergo elective endoscopic thyroidectomy under general anesthesia were enrolled. These patients were randomly allocated to receive sevoflurane based balanced anesthesia (BA group) or propofol-remifentanil anesthesia (TIVA group). PONV was evaluated using a 4-point Likert scale, and pain using a visual analogue scale (VAS; range 0 to 100) for 0-2, 2-6, and 6-24 hours postoperatively. At 24 hours postoperatively, overall patient satisfaction regarding PONV and pain were recorded.

RESULTS

The incidence of PONV was 14.6% in the TIVA group and 51.3% in the BA group. The incidence of nausea at 0-2 and 2-6 hours postoperatively was lower in the TIVA group than in the BA group (4.2% vs. 35.9%, 6.3% vs. 23.1%, respectively), but no between-group difference was observed at 6-24 hours postoperatively (8.3% vs. 5.1%). Antiemetic usage at 0-2 and 2-6 hours was lower in the TIVA than the BA group (4.2% vs. 38.5%, 6.3% vs. 23.1%), but no between-group difference was observed for 6-24 hours (6.3% vs. 7.7%). There were no differences in pain or in patient satisfaction.

CONCLUSIONS

After endoscopic thyroidectomy, total intravenous anesthesia with propofol-remifentanil is associated with less PONV during the early postoperative period (0-6 hours) than sevoflurane based balanced anesthesia.

Remifentanil, a different opioid: potential clinical applications and safety aspects

IMPORTANCE OF THE FIELD

Opioids play an important role in every aspect of modern anesthetic practice. Remifentanil is an ultra-short-acting opioid featuring a unique pharmacokinetic profile allowing clinical versatility and improved control of its action. In this review, we assess the pharmacology of remifentanil, its clinical uses as well as safety issues on its action on the major organ systems and in particular clinical settings.

AREAS COVERED IN THIS REVIEW

A synthesis of evidence from a MEDLINE search for articles from 1993 to 2009 for available up-to-date information on remifentanil and its current applications and safety profile.

WHAT THE READER WILL GAIN

A synopsis of the unique pharmacokinetic properties of remifentanil and its action on major organ systems will provide insight on the safe and effective use of the drug in a variety of clinical settings.

TAKE HOME MESSAGE

Remifentanil is a valuable opioid in the armamentarium of the clinician, providing great clinical flexibility and safety but vigilance is required to avoid pitfalls.

Continuous infusion of two doses of remifentanil immediately after laparoscopic-assisted vaginal hysterectomy

Background

We evaluated the effect and safety of the immediate postoperative continuous infusion of remifentanil at two doses in patients undergoing laparoscopic-assisted vaginal hysterectomy (LAVH) with alfentanil-based patient-controlled analgesia (PCA).

Methods

The study enrolled 50 ASA physical status 1 or 2 patients scheduled to undergo LAVH. Anesthesia was maintained with sevoflurane-remifentanil-air. At the last skin suture, the sevoflurane was discontinued, and patients were randomized to receive remifentanil 0.05 µg/kg/min (group I) or 0.1 µg/kg/min (group II). PCA was started at the time of eye opening and response to a verbal command. In the recovery room, we monitored the mean arterial blood pressure (MAP), heart rate (HR), respiratory rate (RR), SpO₂, and bispectral index (BIS) at 5-minute intervals. Thirty minutes after starting PCA, the remifentanil was discontinued. Pain was assessed using a visual analog scale (0 = no pain; 100 = the worst possible pain) at 0, 5, 10, and 30 minutes after stopping the remifentanil infusion.

Results

The eye opening time, BIS, MAP, and HR did not differ significantly between the two groups, and pain scores were similar between the two groups. Respiratory depression (SpO₂ < 90% or RR < 8/min) did not occur in group I but did occur in three patients in group II.

Conclusions

Continuous remifentanil infusion (0.05 µg/kg/min) immediately postoperatively with alfentanil-based PCA had a similar effect as a 0.1 µg/kg/min infusion with respect to pain control without side effects. However, special attention must be given to respiratory depression.

The potential for mu-opioid receptor agonists to be anti-emetic in humans: a review of clinical data

In animal models of vomiting, mu-opioid (MOP, OP(3)) receptors mediate both emesis and anti-emesis. mu-receptors within the blood-brain barrier, mediating anti-emesis, are more rapidly accessible to lipid-soluble mu-opioid receptor agonists such as fentanyl than to morphine, and fentanyl has broad-spectrum anti-emetic effects in a number of species. Whether a similar situation exists in humans is not known. A search was performed for clinical studies comparing the emetic side effects of opioids administered peri-operatively in an attempt to identify differences between morphine and more lipid-soluble mu-receptor-selective agonists such as fentanyl. Overall, the evidence appears to suggest that fentanyl and other phenylpiperidines are associated with less nausea and vomiting than morphine, but not all studies support this, and fentanyl-like drugs are associated with nausea and vomiting per se. Good evidence, however, exists to show that fentanyl and alfentanil do not cause more nausea and vomiting than the ultra fast-acting remifentanil. Because remifentanil is cleared rapidly post-operatively, such trials suggest that the emetic side effects of fentanyl and alfentanil are minimal. The clinical evidence, although limited, is at least consistent with the possibility that central mu-opioid receptors may mediate anti-emesis in humans. It is possible that the role of mu-opioid agonists in anti-emesis may become clearer in the future as a result of the use of peripheral mu-opioid receptor antagonists.

The effect of intraoperative remifentanil infusion on analgesic requirements after laparoscopic cholecystectomy

BACKGROUND

This study was designed to evaluate the effect of intraoperative remifentanil infusion on postoperative analgesics requirements after laparoscopic cholecystectomy.

METHODS

One hundred adult patients scheduled for elective laparoscopic cholecystectomy were enrolled. Patients were randomly allocated to 2 groups to receive sevoflurane with remifentanil infusion (Group R) or not (group C). Sevoflurane concentration and remifentanil dose were adjusted to maintain BIS 40-60 and blood pressure within 20% of the preoperative value, respectively. We assessed the pain intensity by using the four-point verbal rating scale (VRS) (0 = no pain. 1 = slight pain, 2 = moderate pain, 3 = intense or severe pain) at 15 min intervals for 1 hour in recovery room and then at 3-h intervals for 24 h in surgical ward. The analgesic medication was given when VRS score was > or =2 or patients requested it.

RESULTS

There were no differences between the two groups with respect to the requirements for postoperative analgesics in recovery room and surgical ward.

CONCLUSIONS

Continuous remifentanil infusion (0.09 +/- 0.05 ug/kg/min) during laparoscopic cholecystectomy does not cause hyperalgesia and more analgesic requirements.

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 recovery characteristics, postoperative nausea and vomiting, and gastrointestinal motility with total intravenous anesthesia with propofol versus inhalation anesthesia with desflurane for laparoscopic cholecystectomy: A randomized controlled study

BACKGROUND

Clinical effects, recovery characteristics, and costs of total intravenous anesthesia with different inhalational anesthetics have been investigated and compared; however, there are no reported clinical studies focusing on the effects of anesthesia with propofol and desflurane in patients undergoing laparoscopic cholecystectomy.

OBJECTIVE

The aim of this study was to determine the effects of total intravenous anesthesia with propofol and alfentanil compared with those of desflurane and alfentanil on recovery characteristics, postoperative nausea and vomiting (PONV), duration of hospitalization, and gastrointestinal motility.

METHODS

Patients classified as American Society of Anesthesiologists physical status I or II undergoing elective laparoscopic cholecystectomy due to benign gallbladder disease were enrolled in the study. Patients were randomly assigned at a 1:1 ratio to receive total intravenous anesthesia with propofol (2-2.5 mg/kg) and alfentanil (20 μg/kg) or desflurane (4%-6%) and alfentanil (20 μg/kg). Perioperative management during premedication, intraoperative analgesia, relaxation, ventilation, and postoperative analgesia were carried out identically in the 2 groups. Extubation time, recovery time, PONV, postoperative antiemetic requirement, time to gastrointestinal motility and flatus, duration of hospitalization, and adverse effects were recorded. Postoperative pain was assessed using a visual analogue scale.

RESULTS

Sixty-eight patients were assessed for inclusion in the study; 5 were excluded because they chose open surgery and 3 did not complete the study because they left the hospital. Sixty patients (33 women, 27 men) completed the study. Recovery time was significantly shorter in the propofol group (n = 30) compared with the desflurane group (n = 30) (8.0 [0.77] vs 9.2 [0.66] min, respectively; P < 0.005). Fifteen patients (50.0%) in the propofol group and 20 patients (66.7%) in the desflurane group experienced nausea during the first 24 hours after surgery. The difference was not considered significant. In the propofol group, significantly fewer patients had vomiting episodes compared with those in the desflurane group (2 [6.7%] vs 16 [53.3%]; P < 0.005). Significantly fewer patients in the propofol group required analgesic medication in the first 24 hours after surgery compared with those in the desflurane group (10 [33.3%] vs 15 [50.0%]; P < 0.005). Patients in the propofol group experienced bowel movements in a significantly shorter period of time compared with patients in the desflurane group (8.30 [1.67] vs 9.76 [1.88] hours; P = 0.02). The mean time to flatus occurred significantly sooner after surgery in the propofol group than in the desflurane group (8.70 [1.79] vs 9.46 [2.09] hours; P = 0.01). The duration of hospitalization after surgery was significantly shorter in the propofol group than in the desflurane group (40.60 [3.49] vs 43.60 [3.56] hours; P = 0.03).

CONCLUSION

Total intravenous anesthesia with propofol and alfentanil was associated with a significantly reduced rate of PONV and analgesic consumption, shortened recovery time and duration of hospitalization, accelerated onset of bowel movements, and increased patient satisfaction compared with desflurane and alfentanil in these patients undergoing laparoscopic surgery who completed the study.

Comparison of alfentanil and remifentanil for the use of patient controlled sedation under local anesthesia during ear, nose and throat surgery

BACKGROUND

This study was conducted to compare the effects of alfentanil and remifentanil on patient controlled sedation (PCS).

METHODS

60 patients scheduled for ear, nose and throat surgery under local anesthesia were randomly allocated to Group P (n = 20, propofol 10 mg/ml), Group A (n = 20, propofol 10 mg/ml with alfentanil 500 microg/ml) and Group R (n = 20, propofol 10 mg/ml with remifentanil 10 microg/ml). Without a basal rate, bolus was set to 2 ml with one minute of lockout time.

RESULTS

A total of 57 patients were included in this study. Group A was found to have a lower blood pressure and pulse rate than group R. Group R showed a lower PCS dose upto an OAA/S (Observer's Assessment of Alertness/Sedation Scale) value of 4 and a higher OAA/S prior to surgery than group P. Group P was found to have a higher blood pressure and respiration rate than Group A. During PCS, patient anxiety was significantly decreased in all groups. In addition, there was no differences among groups in the level of pain during the perioperative period, delivery/attempt ratio, satisfaction of the patient and surgeon, and number of patients required to undergo the same PCS technique again. The frequency of side effects of PCS, which included pain on injection, transient hypertension, hypotension, desaturation and oversedation, were similar among groups.

CONCLUSIONS

Evaluation of patients who underwent ear, nose and throat surgery under local anesthesia using PCS with propofol alone or alfentanil or remifentanil revealed no differences in safety, effectiveness, complications or satisfaction of the patients and surgeons.

Prevention of rocuronium-induced withdrawal movement in children: a comparison of remifentanil with alfentanil

BACKGROUND

This study was designed to compare the efficacy of remifentanil and alfentanil without the venous occlusion technique in preventing the withdrawal response associated with rocuronium injection in children.

METHODS

One hundred and twenty children aged between 3 and 10 years were randomly allocated into one of four groups to receive either i.v. remifentanil 0.5 microg.kg(-1) (remi 0.5 group), remifentanil 1 microg.kg(-1) (remi 1.0 group), alfentanil 15 microg.kg(-1) (alfentanil group) or saline 5 ml (saline group). Anesthesia was induced with 2.5% thiopental sodium 5 mg.kg(-1) and the test drug was injected over 30 s. One minute later, 1% rocuronium 0.6 mg.kg(-1) was injected over 5 s and the response was recorded. Mean arterial pressure (MAP) and heart rate (HR) were recorded on arrival in the operating room, before and 1 min after tracheal intubation.

RESULTS

The incidence of withdrawal movement in the saline group (93%) was significantly higher than that in the remi 0.5, remi 1.0, and alfentanil groups (53%, 17%, and 20%, respectively) (P < 0.05). The incidence in the remi 1.0 and alfentanil groups was significantly less than that in the remi 0.5 group (P < 0.05). After intubation, MAP and HR were significantly higher in the saline group than that in remi 1.0 and alfentanil groups.

CONCLUSIONS

Both remifentanil 1 microg.kg(-1) and alfentanil 15 microg.kg(-1) can be used to prevent rocuronium-associated withdrawal movement in children because they are equally effective and attenuate the increase in MAP and HR after intubation.

Remifentanil for general anaesthesia: a systematic review

We performed a quantitative systematic review of randomised, controlled trials that compared remifentanil to short-acting opioids (fentanyl, alfentanil, or sufentanil) for general anaesthesia. Eighty-five trials were identified and these included a total of 13 057 patients. Intra-operatively, remifentanil was associated with clinical signs of deeper analgesia and anaesthesia, such as fewer responses to noxious stimuli (relative risk 0.65, 95% CI 0.48-0.87), more frequent episodes of bradycardia (1.46, 1.04-2.05), more hypotension (1.68, 1.36-2.07) and less hypertension (0.60, 0.46-0.78). Postoperatively, remifentanil was associated with faster recovery (difference in extubation time of -2.03, 9.5% CI, -2.92 to -1.14 min), more frequent postoperative analgesic requirements (1.36, 1.21-1.53) and fewer respiratory events requiring naloxone (0.25, 0.14-0.47). Remifentanil had no overall impact on postoperative nausea (1.03, 0.97-1.09) or vomiting (1.06, 0.96-1.17), but was associated with twice as much shivering (2.15, 1.73-2.69). Remifentanil does not seem to offer any advantage for lengthy, major interventions, but may be useful for selected patients, e.g. when postoperative respiratory depression is a concern.

Remifentanil-propofol in vertebral disk operations: hemodynamics and recovery versus desflurane-n(2)o inhalation anesthesia

The purpose of this study was to ascertain whether total intravenous anesthesia (TIVA) with propofol and remifentanil differs from inhalational anesthesia with desflurane and nitrous oxide in terms of hemodynamics, recovery profile, and postoperative analgesic demand in patients undergoing elective microsurgical vertebral disk resection. A total of 60 patients were randomly assigned to receive TIVA with propofol and remifentanil or inhalational anesthesia with desflurane and nitrous oxide. The TIVA group (n=30) then received 50%/50% N(2)O/O(2). A constant infusion of remifentanil was provided at 0.125 microg/kg/min accompanied by propofol at 10 mg/kg/h in the first 10 min, 6 mg/kg/h in the second 10 min, then 4 mg/kg/h. The desflurane group (n=30) received 50%/50% N(2)O/O(2), with 5% desflurane after intubation and 6% before incision; desflurane was administered in a minimum alveolar concentration 1 fashion during the operation. Hemodynamic, O(2) saturation, and end-tidal CO(2) data were recorded before induction, after intubation, after prone positioning, 5, 10, 15, 20, and 30 min into the operation, and at 15-min intervals thereafter until the end of the operation. Details on perioperative bradycardia, hypotension or hypertension, spontaneous breathing, extubation, eye opening, recovery time of ability to give name and date of birth, postoperative nausea and vomiting, shivering, agitation, and hypoxia were recorded. Patients anesthetized with desflurane responded to skin incision with increasing blood pressure and tachycardia; however, no other hemodynamic differences were noted between the 2 groups. In the TIVA group, recovery times were shorter for spontaneous ventilation (2.33-3.53 min), extubation (3.13-3.88 min), eye opening (4.06-6.23 min), and being able to give name and date of birth (5.4-7.9 min) compared with times in the desflurane group (P<.05). In the TIVA group, more postoperative shivering (16.7% of patients) and greater analgesic demand were seen than in the desflurane group. Although nausea and vomiting were more common in the desflurane group, no difference in bronchospasm was reported. In the TIVA group, a shorter recovery period and a greater demand for postoperative analgesia were seen. Because of the lack of residual analgesic effects, postoperative analgesic treatment should be initiated immediately in patients undergoing TIVA.

Spectral frequency index monitoring during propofol-remifentanil and propofol-alfentanil total intravenous anaesthesia

BACKGROUND

The aim of this study was to evaluate the usefulness of spectral frequency index (SFx) monitoring to assess the depth of anaesthesia during propofol-opioid total intravenous anaesthesia (TIVA).

METHODS

Thirty-three patients scheduled for laparoscopic cholecystectomy under propofol TIVA were prospectively and randomly allocated to receive either remifentanil (bolus of 1.0 microg/kg, followed by continuous infusion from 0.25 to 0.05 microg/kg/min) [n = 18] or alfentanil (bolus of 10 microg/kg, followed by continuous infusion from 2.0 to 0.5 microg/kg/min) [n = 15]. EEG activity was monitored to achieve the desired depth of anaesthesia, and intravenous propofol was titrated to keep the SFx at 70-80%. The remifentanil and alfentanil groups were compared in relation to the plasma propofol concentration required for an adequate level of hypnosis during maintenance of anaesthesia, Pearson correlation coefficient for the relationship between the plasma propofol concentration and SFx values, recovery parameters, and recall of events during anaesthesia.

RESULTS

The study groups were comparable with regard to demographic characteristics, type and duration of surgery, and time to resumption of spontaneous ventilation. No evidence of explicit recall was noted. The mean plasma propofol concentration required for an adequate level of hypnosis during maintenance of anaesthesia was significantly higher in the alfentanil group (3.20 microg/mL) compared with the remifentanil group (2.17 microg/L) [p < 0.05]. In both groups, the Pearson correlation coefficient test showed a linear correlation between SFx values and propofol concentration in the studied propofol concentration range. The mean time to orientation for name and place was significantly shorter (p < 0.05), the mean propofol concentration at orientation for name and place and at the resumption of spontaneous ventilation timepoints was significantly lower (both p < 0.01), and the mean SFx value at resumption of spontaneous ventilation timepoint was significantly higher (p < 0.01) in the remifentanil group.

CONCLUSIONS

As SFx is linearly related to plasma propofol concentration, this index may be used to measure anaesthetic effect during propofol anaesthesia. The results of this clinical trial are consistent with a previous computer-simulated opioid-propofol model with regard to intraoperative and recovery variables, although the recovery occurred at different propofol concentration and SFx values.

Remifentanil update: clinical science and utility

The anilidopiperidine opioid remifentanil has pharmacodynamic properties similar to all opioids; however, its pharmacokinetic characteristics are unique. Favourable pharmacokinetic properties, minimally altered by extremes of age or renal or hepatic dysfunction, enable easy titration and rapid dissipation of clinical effect of this agent, even after prolonged infusion. Remifentanil is metabolised by esterases that are widespread throughout the plasma, red blood cells, and interstitial tissues, whereas other anilidopiperidine opioids (e.g. fentanyl, alfentanil and sufentanil) depend upon hepatic biotransformation and renal excretion for elimination. Consequently, remifentanil is cleared considerably more rapidly than other anilidopiperidine opioids. In addition, its pKa (the pH at which the drug is 50% ionised) is less than physiological pH; thus, remifentanil circulates primarily in the non-ionised moiety, which quickly penetrates the lipid blood-brain barrier and rapidly equilibrates across the plasma/effect site interface. By virtue of these distinctive pharmacokinetic properties, the context-sensitive half-time (i.e. the time required for the drug's plasma concentration to decrease by 50% after cessation of an infusion) of remifentanil remains consistently short (3.2 minutes), even following an infusion of long duration (> or =8 hours). Remifentanil, a clinically versatile opioid, is useful for intravenous analgesia and sedation in spontaneously breathing patients undergoing painful procedures. Profound analgesia may be achieved with minimal effect on cognitive function. Remifentanil may also provide sedation and analgesia during placement of regional anaesthetic blocks, and in conjunction with topical anaesthesia and airway nerve blocks, it may be useful for blunting reflex responses and facilitating 'awake' fibreoptic intubation. Compared with fentanyl and alfentanil in a day-surgery setting, remifentanil supplementation of general anaesthesia may improve intraoperative haemodynamic control. Both emergence time and the incidence of respiratory depression during post-anaesthetic recovery may be reduced. However, outcomes such as home discharge time, post-emergence adverse effect profile, and patient and provider satisfaction are not significantly improved, and the incidence of intraoperative hypotension and bradycardia is greater. In addition, drug acquisition costs for remifentanil are higher and clinicians may need extra time to familiarise themselves with the drug's unique pharmacokinetics.Ironically, the quick dissipation of opioid analgesic effect following remifentanil discontinuation may be a significant clinical disadvantage. Unless little or no postoperative pain is anticipated, the clinician may wish to treat prospectively using local or regional anaesthesia, non-opioid analgesics, or longer-acting opioid analgesics.

Remifentanil: an update

PURPOSE OF REVIEW

Remifentanil has now reached maturity, as reflected by the increasing number of clinical papers relating to its use. Its position among anaesthetic drugs is now better understood, and this review will attempt to place it in the context of current clinical practice.

RECENT FINDINGS AND SUMMARY

Propofol reduces the initial distribution of remifentanil, leading to higher concentrations during induction. Propofol and remifentanil administered together at sedative doses display a major synergistic interaction on the respiratory drive. Remifentanil accelerates the penetration of sevoflurane to its site of effect. The risk of intraoperative awareness seems to be low when remifentanil is associated to very low concentrations of hypnotic drugs, but this field warrants further investigation. Acute tolerance to opioids and its prevention remain controversial.

SUMMARY

Remifentanil is the opioid of choice for tracheal intubation without muscle relaxants. It provides an alternative to regional anaesthesia in labour pain control. Target-controlled infusion may further improve the administration of remifentanil.

Remifentanil-propofol vs. sufentanil-propofol: optimal combinations in clinical anesthesia

BACKGROUND

Two opioid regimens, computer-simulated to provide optimal general anesthesia in combination with propofol, were compared using clinical criteria.

METHODS

Fifty patients undergoing thyroid surgery were blindly, prospectively and randomly allocated to receive either (a) i.v. remifentanil (1.5 micro g kg-1, followed by 0.2 micro g kg-1 min-1) or (b) i.v. sufentanil (0.2 micro g kg-1 followed by 0.2 micro g kg-1 h-1). Remifentanil infusion was stopped at the last skin suture. Sufentanil infusion was stopped 30 min before the end of surgery. Intravenous propofol was titrated to keep BIS at 50+/-5. Remifentanil and sufentanil groups were compared with regards to (a) propofol delivery, (b) hemodynamic and recovery variables, and (c) effect-site propofol levels during a steady-state period for effect-site remifentanil and sufentanil levels. P<0.05 was significant.

RESULTS

Groups were similar in demographic data; types and durations of surgery; total propofol consumption; and response, extubation and emergence times. During the steady-state period for the opioid delivery, the remifentanil and sufentanil effect-site levels were 5.3 ng ml-1 and 0.18 ng ml-1, respectively (potency ratio=30). In both opioid groups, in accordance with previous computer-simulations, the effect-site propofol concentrations remained (a) within a narrow range unaffected by surgical stimuli, (b) significantly smaller in the remifentanil group than in the sufentanil group, but (c) smaller than expected from previous computer-simulations. More patients required ephedrine following induction of anesthesia in the remifentanil compared with the sufentanil group.

CONCLUSIONS

The present clinical trial conducted in thyroid surgery is consistent with previous computer-simulated opioid-propofol combinations with respect to intraoperative and recovery variables. Effect-site propofol ranges were, however, lower than expected.