Comparison of fentanyl, sufentanil, and alfentanil anesthesia in patients undergoing valvular heart surgery

The hemodynamic responses to anesthesia and surgery were studied in three groups of 20 patients undergoing valve replacement surgery. Anesthesia was induced with either fentanyl (75 micrograms/kg), sufentanil (15 micrograms/kg), or alfentanil (125 micrograms/kg). Pancuronium (8 mg) was given for muscle relaxation and the lungs were ventilated with oxygen/air (FIO2 = 0.5). Additional fentanyl (25 micrograms/kg) or sufentanil (5 micrograms/kg) was given before skin incision. Patients receiving alfentanil were given a continuous infusion at a rate of 0.5 mg X kg-1 X hr-1. Only mean arterial blood pressure (MABP) and systemic vascular resistance (SVR) changed significantly in response to anesthesia or surgery. MABP decreased on average 24.5 mm Hg (P less than 0.01) after induction of anesthesia with sufentanil in patients with mitral valve disease. MABP and SVR increased significantly (P less than 0.01) in patients with aortic valve disease receiving fentanyl. There were no other statistically significant changes within the groups. Four patients (two in the sufentanil group and one from each of the other groups) developed transient hypotension during induction of anesthesia. It is concluded that all three opioids can provide satisfactory anesthesia for patients having valve replacement surgery.     

The haemodynamic effects of bronchoscopy Comparison of propofol and thiopentone with and without alfentanil pretreatment

The haemodynamic response to bronchoscopy under general anaesthesia was investigated. Forty patients were allocated at random to receive either thiopentone or propofol; half the patients in each group received in addition 18 micrograms/kg of alfentanil one minute before induction of anaesthesia. The heart rate, noninvasive blood pressure and Holter ECG was monitored in all patients. Significant increases in heart rate (p less than 0.05), systolic and diastolic arterial pressures (p less than 0.01) occurred in the thiopentone only group, following bronchoscopy. Systolic and diastolic arterial pressure decreased in patients receiving thiopentone plus alfentanil, following induction of anaesthesia and laryngoscopy (p less than 0.05). No significant haemodynamic changes were seen in either of the groups which received propofol. ST segment changes on subsequent Holter analysis were seen in four patients, but there were no significant differences between the groups. Anaesthesia with propofol alone provides adequate haemodynamic stability for bronchoscopy and the addition is superfluous.     

Reducing the haemodynamic responses to laryngoscopy and intubation

The effects of alfentanil and fentanyl on controlling the haemodynamic responses to laryngoscopy and intubation have been compared. Five groups of ten patients were studied. Induction was with thiopentone 4 mg/kg. Thirty seconds later group 1 received 1 ml/20 kg saline, group 2 received 15 micrograms/kg alfentanil, group 3 received 30 micrograms/kg alfentanil and group 4 received 5 micrograms/kg fentanyl one minute before induction. Suxamethonium was given 60 seconds after induction and intubation of the trachea was performed 150 seconds after the start of induction. Heart rate and mean arterial pressure were recorded every minute throughout and compared with pre-induction control values. Control patients (group 1) showed significant increases associated with tracheal intubation in all haemodynamic variables. No increases were noted in groups receiving 30 micrograms/kg alfentanil or 5 micrograms/kg fentanyl. The heart rate, but not blood pressure, increased with intubation after 15 micrograms/kg alfentanil. The mean time to movement in 50% of the control patients was 7 minutes. In those given 15 and 30 micrograms/kg alfentanil it was 11 and 12 minutes respectively. In those given 5 micrograms/kg fentanyl it was greater than 15 minutes. Alfentanil is shown to reduce the cardiovascular responses to laryngoscopy and intubation and the effect appears to have a shorter duration than that of fentanyl.     

Antagonism of fentanyl and alfentanil by intravenous plus subcutaneous naloxone

Twenty patients undergoing microlaryngoscopy were anaesthetized with thiopentone. Half received fentanyl supplementation (about 8.5 micrograms/kg) and the other half alfentanil (about 65 micrograms/kg). Both groups were given naloxone 0.4 mg intravenously plus 0.4 mg subcutaneously shortly after the procedure which lasted some 12 minutes. The degree of ventilatory depression was assessed by a CO2 rebreathing test. The ventilation at an end-tidal PCO2 of 8.0 kPa (V8.0) was noted, and the findings related to a control value obtained on the day before anaesthesia. In the fentanyl group, V8.0 was significantly (p less than 0.05) less one hour after naloxone than 15 minutes after, and remained significantly below the control value for the first 8 hours after microlaryngoscopy. A second peak in plasma fentanyl concentration was observed four hours postoperatively in three patients. Respiratory depression in the alfentanil group was less pronounced and of shorter duration than in the fentanyl group. Postoperative plasma alfentanyl concentration decreased progressively with time in every patient.     

Effects of alfentanil and fentanyl on common bile duct pressure

The effects of alfentanil (7.5 or 15 micrograms/kg) and fentanyl (1.5 micrograms/kg) on common bile duct pressure were examined by using an indwelling postoperative T-tube in 36 conscious, unpremedicated patients. All opiate doses significantly (P less than 0.001) increased the pressure. There was no significant difference among the groups in the peak pressures nor in the times to peak pressures. Fentanyl had a significantly longer duration of effect on pressure.     

A comparison of oxymorphone and fentanyl as narcotic supplements in general anesthesia

The safety and efficacy of two potent opiate analgesics, fentanyl and oxymorphone, used as adjuncts in general anesthesia, were studied in 39 patients undergoing elective gynecologic surgery of at least 2 hours duration. Based on a potency ratio of 10:1, patients received either fentanyl 6.5 micrograms/kg or oxymorphone 65 micrograms/kg prior to a thiopental 2 to 3 mg/kg succinylcholine induction and endotracheal intubation. Additional maintenance narcotic and isoflurane were administered as required by the "blinded" anesthesiologist in response to hemodynamic alterations 15% above a presurgical baseline. Overall analysis included hemodynamic response at preset intraoperative intervals, total anesthetic requirements, and stability of vital signs in the recovery room. Blood pressure and heart rate were reliably controlled with either agent; however, less narcotic (ml) and recovery room analgesics were required in the oxymorphone-treated group (p less than 0.05). Decreased naloxone requirements (p less than 0.05) and a more rapid emergence suggested that fentanyl was a safer agent when administered in relatively unrestricted fashion.     

Analgesia for appendectomy: comparison of fentanyl and alfentanil in children

During etomidate-N2O vecuronium anaesthesia for appendectomy, three groups of 13 children received fentanyl as a 10 micrograms.kg-1 loading dose and 2 micrograms.kg-1 increments in Group F, alfentanil as a 100 micrograms.kg-1 initial loading dose and either 20 micrograms.kg-1 increments in Group AB or 1 microgram.kg-1.min-1 continuous infusion in Group AI. On the basis of intraoperative heart rate changes, the opioid regimen was less efficient in Group AB (P less than 0.05). Based upon equianalgesic cumulative dosage, the alfentanil/fentanyl potency ratio was in the range of 1/10 to 1/13. The awakening time was similar in all groups, as were the duration of postoperative analgesia, the incidence of postoperative pain and the incidence of nausea and vomiting. We conclude that high-dose alfentanil is as efficient as fentanyl for intra and postoperative analgesia in children undergoing appendectomy.     

Continuous opioid infusions for neurosurgical procedures: a double-blind comparison of alfentanil and fentanyl

The ability of continuous infusions of opioids to control hypertension at the end of neurosurgical procedures without compromising prompt emergence was studied in patients undergoing craniotomy for supratentorial tumours. Four infusion regimens were compared in a randomized double-blind fashion; three of alfentanil and one of fentanyl. Low-dose alfentanil was administered to nine patients (35.1 micrograms.kg-1 then a continuous infusion of 16.2 micrograms.kg-1.hr-1); mid-dose alfentanil to eight patients (70.2 micrograms.kg-1 then 32.4 micrograms.kg-1.hr-1); high-dose alfentanil to eight patients (105.3 micrograms.kg-1 then 48.6 micrograms.kg-1.hr-1). Eight additional patients were given fentanyl (8.3 micrograms.kg-1 then 1.6 micrograms.kg-1.hr-1). Using published values for the pharmacokinetic variables of alfentanil and fentanyl, modelling predicted stable concentrations of 60, 120, 180 ng.ml-1 for the alfentanil infusion regimens respectively and 2 ng.ml-1 with the fentanyl regimen. Maintenance anaesthesia comprised the opioid infusion, 50% N2O in O2 and isoflurane titrated to control mean arterial pressure (MAP) within 20% of ward MAP. Isoflurane was discontinued after closure of the dura. Nitrous oxide was discontinued at the same time as reversal of neuromuscular blockade. The opioid infusion was discontinued with closure of the galea. A greater time-averaged isoflurane concentration was required to control MAP within the prescribed limits in the low alfentanil group (ANOVA; P less than 0.05). The PaCO2 at two, five and 30 min after extubation were not different among groups. The times from discontinuing N2O to eye opening and tracheal extubation were not different. The time to follow commands was longer in the low alfentanil group (P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)     

The analgesic effect of a low dose of alfentanil

The effect of a single small dose of alfentanil (6 micrograms/kg) on postoperative pain was compared with saline using a double blind study. Pain was assessed using a linear analogue scale and shown to decrease at 2, 5 and 10 minutes after injection of alfentanil (p less than 0.01). The PE'CO2 was increased at 2 and 15 minutes (p less than 0.05) and 5 and 10 minutes (p less than 0.01) after injection of alfentanil. There were no changes in pain or PE'CO2 in the control group throughout the study. Intravenous alfentanil given to patients in pain provides quick effective analgesia for a short period of time, but respiratory depression may occur.     

Cerebrospinal fluid pressure in patients with brain tumors: impact of fentanyl versus alfentanil during nitrous oxide-oxygen anesthesia

The effects on the cerebrospinal fluid pressure (CSFP) of alfentanil and fentanyl were compared during nitrous oxide-oxygen (N2O-O2) anesthesia in 24 patients who had brain tumors. Monitored variables included CSFP (lumbar subarachnoid catheter), heart rate from electrocardiographic lead II, mean radial arterial blood pressure, and arterial blood gas tensions. General anesthesia was induced with thiopental, 5 mg/kg IV in divided doses, and maintained with 70% N2O in O2; ventilation was held constant (PaCO2 = 37.4 +/- 1.6 mm Hg [mean +/- SEM]). After baseline data were recorded, 16 subjects were randomly assigned to receive either 5 micrograms/kg fentanyl as an intravenous bolus or 50 micrograms/kg alfentanil as an intravenous bolus, followed by an infusion of alfentanil at 1 micrograms.kg-1.min-1. Monitored variables were continuously recorded for 15 min after opioid injection. A third group of 8 patients was studied subsequently; they received only N2O-O2 during a 15-min observation period and served as controls. Blood pressure was held constant with an intravenous infusion of 0.1% phenylephrine, as needed; noxious stimulation was carefully avoided. Cerebrospinal fluid pressure remained unchanged both in patients who received N2O-O2 alone and in those who received fentanyl-N2O-O2. By contrast, those who received alfentanil-N2O-O2 had a gradual increase in CSFP, reaching 30% above baseline values after 10 min and stabilizing thereafter. Although the absolute increase in CSFP during normocarbic alfentanil-N2O anesthesia was relatively small (9.5 +/- 1.3 mm Hg to 13.0 +/- 1.3 mm Hg [mean +/- SE], P less than 0.05), the absence of a similar effect after fentanyl administration suggests that precautionary measures such as hyperventilation are advisable if alfentanil is used for potentiating normocarbic N2O-O2 anesthesia in neurosurgical patients with intracranial mass lesions.     

A comparison between the effects of fentanyl, droperidol with fentanyl, and halothane anaesthesia on intra-ocular pressure in adults

The effects of fentanyl 3.0 micrograms/kg (group 1), droperidol 0.1 mg/kg with fentanyl 3.0 micrograms/kg (group 2), and halothane 0.5% inspired concentration (group 3) on intra-ocular pressure were compared. In each group, a decrease in intra-ocular pressure was produced which was significantly lower than resting values (p greater than 0.01) and was independent of changes in arterial blood pressure. The recovery time in group 1 patients was significantly less than that of patients in group 3.     

Analgesia for retrobulbar block--comparison of remifentanil, alfentanil and fentanyl

BACKGROUND: The injection of retrobulbar block is associated with significant pain and discomfort. Therefore a short-acting IV analgesic before retrobulbar injection has been advocated. OBJECTIVE: To compare remifentanil, alfentanil and fentanyl in providing analgesia for retrobulbar block injection. METHODS: 69 patients were enrolled randomly into three groups of 23 each to receive either Remifentanil 1 microg/kg, Alfentanil 20 microg/kg or Fentanyl 2 microg/kg as an IV bolus dose prior to retrobulbar injection. Mean arterial pressure (MAP) and heart rate (HR) were recorded and Numerical Pain Score (NPS) were assessed by a blinded observer. RESULTS: Remifentanil prevented increase in MAP and HR while alfentanil and fentanyl were ineffective in this purpose (p < 0.05). NPS was significantly lower in remifentanil group (p < 0.05). CONCLUSION: Remifentanil 1 microg/kg prior to retrobulbar injection provide excellent hemodynamic stability and ensure analgesia.     

Alfentanil combined with vecuronium or pancuronium: haemodynamic implications

Forty-two fit, anticholinergized patients, induced with thiopentone, received either vecuronium (V) or pancuronium (P) 0.1 mg/kg, followed by alfentanil 15 micrograms/kg. The mean heart rate in the Group V was significantly lower than that in the Group P. The difference, 10-15 bpm, appeared after alfentanil administration, and lasted for 5 min postintubation, when under N2O anaesthesia. The Group P patients maintained their arterial pressure closer to the preinduction level than did the Group V patients, but a statistically significant inter-group difference appeared only at two recording stages. Four Group V patients, contrasted to none of the Group P patients (P less than 0.05), were put in head-down tilt, or were given atropine, and/or etilephrine for an undue decrease in arterial pressure. Compared to vecuronium, pancuronium increased heart rate, and protected from arterial hypotension, when combined with low-dose alfentanil.     

Intravenous anaesthesia with propofol and alfentanil. The influence of age and weight

Sixty healthy patients undergoing body surface surgery were anaesthetised with continuous infusions of propofol (200 micrograms/kg/minute) and alfentanil (0.25 microgram/kg/minute). Additional bolus doses of propofol (20 mg) were given if movement occurred. The incidence of patient movement in response to skin incision was significantly less in patients over 45 years of age than in those below 45 years (p less than 0.05). Maintenance dosage of propofol sufficient to abolish movement decreased with increasing age (p less than 0.001). Systolic blood pressure decreased in most patients over the first 10 minutes of anaesthesia and the magnitude of this decrease increased with age (p less than 0.0001). These parameters did not correlate strongly with body weight. Dose requirements of propofol are not the same for patients of all ages and strongly suggest that young and old patients should not be treated as a homogeneous group, either for investigative or clinical purposes.     

The pharmacokinetics of alfentanil (R39209): a new opioid analgesic

The pharmacokinetics of alfentanil (R39209), a new short-acting opioid analgesic, have been studied in eleven patients. Six patients were given 50 micrograms/kg alfentanil and five patients 125 micrograms/kg as an intravenous bolus injection. Plasma concentrations were measured at intervals up to 6 h (50 micrograms/kg) or 8-10 h (125 micrograms/kg), using a specific radioimmunoassay technique. Plasma concentrations declined triexponentially in both groups. The initial elimination of alfentanil from the plasma was very rapid with 90% of the administered dose leaving the plasma within 30 min. The average half-lives for the three phases were similar for both groups. The combined mean (+/- SEM) half-lives for the 11 patients for the rapid and slow distribution phases were short (t 1/2 pi = 1.2 +/- 0.26 min, t 1/2 alpha = 11.6 +/- 1.63 min). The elimination half-life, t 1/2 beta was 94 +/- 5.87 min which is considerably shorter than that of other opioids. The mean (+/- SEM) total body clearance was 6.4 +/- 1.39 ml . kg-1 . min-1 and the volume of distribution (Vd) was 0.86 +/- 0.194 l/kg. The latter is considerably less than reported values for the chemically related drug, fentanyl, and suggests that alfentanil may have a lower tissue binding affinity than fentanyl. The rapid elimination and short duration of clinical action suggests the feasibility of repeated administration of alfentanil and its use by continuous intravenous infusion.     

Disoprofol (ICI 35868) for Total Intravenous Anaesthesia

The purpose of this study was to evaluate disoprofol as the hypnotic for total intravenous anaesthesia. Sixty women undergoing minor gynaecological surgery participated and were randomly assigned to four groups (N = 15 in each group). Disoprofol, 2 mg/kg was given i.v. to induce anaesthesia after a bolus injection of either fentanyl 1.875 micrograms/kg or alfentanil 18.75 micrograms/kg. Vecuronium, 0.06 mg/kg, was given for muscle relaxation when indicated. One-half of the patients received acute premedication with midazolam, 5 mg i.v. Anaesthesia was maintained with a continuous infusion of disoprofol 150 micrograms/kg/min and either fentanyl 0.125 micrograms/kg/min or alfentanil 1.25 micrograms/kg/min. These drug combinations were compatible and produced good operating conditions. Awakening time was significantly shorter for women who received no premedication and was not affected by the narcotic used. Respiration returned more quickly when fentanyl was the narcotic given and was not affected by premedication. Both hypotension and bradycardia were seen in some patients, but other side effects were infrequent. This total intravenous anaesthesia technique was very well accepted by the patients and the nurses who cared for them in the postoperative period.     

Obtunding the sympathetic response to intubation. Experience at 2 minutes after administration of the test agent in patients with cerebral aneurysms

The sympathetic response to laryngoscopy and intubation was studied in 39 patients who were to undergo surgical clipping of a cerebral aneurysm. Intravascular radial artery pressure and ECG monitoring for ST-segment changes or dysrhythmias were used. Ward blood pressures were controlled on bed rest and labetalol. Induction of anaesthesia was with pentothal 4 mg/kg and suxamethonium 1 mg/kg intravenously. This was followed by one of the following intravenous agents by random choice: alfentanil 30 micrograms/kg, fentanyl 5 micrograms/kg, lignocaine 2 mg/kg, and lignocaine 10% spray 2 mg/kg to the larynx. ECG changes at laryngoscopy and intubation were minimal. Intubation produced an immediate increase in blood pressure and pulse rate, maximal at 30-60 seconds, falling rapidly towards normal within 2-3 minutes. Alfentanil was very effective in obtunding this response with stable cardiovascular parameters; fentanyl produced a more variable response; and intravenous lignocaine was less satisfactory. Lignocaine spray was ineffective.     

Sufentanil, alfentanil, and fentanyl: impact on cerebrospinal fluid pressure in patients with brain tumors

In order to evaluate the safety of the new synthetic opioids, alfentanil and sufentanil, in neurosurgical patients, we administered sufentanil 1 microg/kg i.v., alfentanil 50 microg/kg i.v. followed by an infusion of 1 microg/kg/min, or fentanyl 5 microg/kg i.v. to 30 patients with supratentorial tumors anesthetized with nitrous oxide (N2O), 60% in O2. Lumbar cerebrospinal fluid pressure (CSFP) and mean arterial pressure (MAP) responses were recorded for 10 min thereafter, while ventilation was held constant [mean PaCO2 = 36.1 +/- 1.0 mm Hg (SEM)]. There was no change in CSFP after fentanyl. In contrast, both sufentanil and alfentanil caused increases in CSFP, equal to 89 +/- 31 % SE (p < 0.05) and 22 +/- 5% (p < 0.05), respectively. MAP decreased after administration of each opioid. Peak decreases in cerebral perfusion pressure (MAP - CSFP) were 14 +/- 3% after fentanyl, 25 +/- 5% after sufentanil, and 37 +/- 3% after alfentanil. It is concluded that because sufentanil increased CSFP in patients who have brain tumors, it also may be contraindicated in other neurosurgical patients at risk for intracranial hypertension. Alfentanil may share this propensity, since CSFP increased despite a profound reduction in MAP. Among the three opioids evaluated, only fentanyl appears to be appropriate for supplementing N2O-2 anesthesia in patients who have compromised intracranial compliance.     

Postoperative gastric emptying in outpatient anesthesia: the effect of opioid supplementation

Acetaminophen (paracetamol) 20 mg/kg was administered orally to 45 gynecological outpatients who had received either alfentanil 5 micrograms/kg, fentanyl 1 microgram/kg, or no analgesic supplement immediately prior to the induction of general anesthesia. Postoperative gastric emptying, assessed by acetaminophen absorption, was significantly inhibited in those given alfentanil. This inhibition is unlikely to be of great clinical importance and was much less than that found in previous studies using longer-acting opioids such as morphine.     

Anaesthesia for laparoscopy: alfentanil and fentanyl compared

A double blind comparison was made between alfentanil and fentanyl as analgesic components of anaesthesia. Sixty-six women undergoing laparoscopy received methohexitone, alcuronium, nitrous oxide and oxygen, with either alfentanil 0.75 mg or fentanyl 0.25 mg. Ten of the patients who received alfentanil and 1 patient who received fentanyl required supplementation of anaesthesia by enflurane. Recovery from anaesthesia was similar in the two groups of patients though the onset of spontaneous breathing occurred more quickly after alfentanil (P less than 0.002). The injection of fentanyl was followed by a fall in BP (P less than 0.05) and the mean minimum value for pulse rate occurring after fentanyl was slower than after alfentanil (P less than 0.05).