Myocardial metabolism and haemodynamic responses during high-dose fentanyl anaesthesia for coronary patients

Fentanyl (mean dose 109 micrograms X kg-1) and oxygen were given to ten patients having coronary vein grafts. Serial studies were done before, during and after operation, of central and mean arterial pressures (MAP), cardiac index (CI) and coronary sinus flow (CBF) by thermodilution, myocardial oxygen consumption (MVO2) and lactate extraction (MLE). On induction CI and stroke work index decreased, but heart rate and MAP were unchanged as systemic resistance increased. Mean MAP and heart rate remained at the awake levels. Mean CBF remained unchanged along with stable MAP and coronary resistance. Oxygen content of CS blood increased on induction and remained elevated until the incision; it was above the awake level early postoperatively. MVO2 was low normal when the patients were awake and remained so. Normal MLE continued with a few exceptions. High-dose fentanyl did not uniformly abolish autonomic reflexes. Heavy premedication, complete beta adrenergic blockade and a high initial doses of fentanyl plus its continued infusion, aided in retaining a hypodynamic circulation and myocardial oxygenation.     

A comparison of remifentanil and fentanyl for fast track paediatric cardiac anaesthesia

BACKGROUND: Fast track anaesthetic protocols for cardiac surgical patients have been developed to facilitate early tracheal extubation. We compared anaesthetics based on either remifentanil or fentanyl for fast track paediatric cardiac anaesthesia. METHODS: Fifty patients with atrial septal defect or simple ventricular septal defect who were deemed suitable for fast track anaesthetic management were randomly assigned to group R (remifentanil) or group F (fentanyl). After sevoflurane induction, patients received either R infusion or F bolus. Following intubation, isoflurane 0.5 MAC was administered to all patients. Blood pressure (BP) and heart rate (HR) were recorded at baseline and pre- and postinduction, intubation, skin incision and sternotomy. Other parameters measured included time to extubation, reintubation rate and requirements for postoperative analgesia, ondansetron, and nitroprusside in the paediatric intensive care unit. RESULTS: BP decreased similarly from baseline in both groups. Decreases in HR over time were significantly greater in group R. Haemodynamic response to incision/sternotomy was low and similar in both groups. There were no significant differences in extubation time, reintubation incidence, postoperative narcotic requirements, postoperative hypertension or postoperative nausea/vomiting. CONCLUSIONS: The remifentanil based anaesthetic was associated with a significantly slower HR than the fentanyl based anaesthetic. The clinical implications of the slower HR during remifentanil anaesthesia could be important and should be investigated.     

A comparison of remifentanil and fentanyl in patients undergoing surgery for intracranial mass lesions

We compared the effects of remifentanil versus fentanyl during surgery for intracranial space-occupying lesions. Patients were randomly assigned to receive either remifentanil (0.5 microg. kg(-1). min(-1) IV during the induction of anesthesia reduced to 0.25 microg. kg(-1). min(-1) after endotracheal intubation; n = 49) or fentanyl (dose per usual practice of the anesthesiologist; n = 54). Anesthesia maintenance doses of isoflurane, nitrous oxide, and opioid were at the anesthesiologist's discretion for both groups. There were no differences between opioid groups for the frequency of responses (hemodynamic, movement, and tearing) to intubation, pinhead holder placement, skin incision, or closure of the surgical wound. Adverse event frequencies were similar between groups. Times to follow verbal commands (P < 0.001) and tracheal extubation (P = 0. 04) were more rapid for remifentanil. The percentage of patients with a normal recovery score (were alert or arousable to quiet voice, were oriented, were able to follow commands, had motor function unchanged from their preoperative evaluation, were not agitated, and had modified Aldrete Scores of 9-10) at 10 min after surgery was more for remifentanil (45% vs 18%; P = 0.005). By 20 min, no difference between groups existed (P = 0.27). Anesthesiologists used more isoflurane in the fentanyl group (4.22 vs 1.93 minimum alveolar anesthetic concentration hours). Neurosurgeons, blinded to treatment group, favored the use of remifentanil. Similar frequencies of light anesthesia responses and other adverse events suggest that intraoperative depths of anesthesia were similar in the two groups. Under these conditions, emergence was more rapid with remifentanil. This is consistent with the necessity for less isoflurane use in the remifentanil group and the intrinsic rapid clearance of this opioid. IMPLICATIONS: Patients given remifentanil-based anesthesia for craniotomy had faster recovery times from anesthesia than did those given fentanyl-based anesthesia.     

Early extubation after high-dose fentanyl anaesthesia for aortocoronary bypass surgery: reversal of respiratory depression with low-dose nalbuphine

To investigate the possibility of selective reversal of narcotic-induced respiratory depression following fentanyl anaesthesia, we studied 20 patients after aortocoronary bypass surgery. All patients were anaesthetized with fentanyl, 40 micrograms . kg-1 and oxygen, with isoflurane as indicated. In a random double blind fashion either incremental doses of nalbuphine, or normal saline were administered approximately four hours after cardiopulmonary bypass. Respiratory depression was evaluated using blood gas and end tidal CO2 (PETCO2) measurement, and in addition, a ventilatory response to CO2 was obtained preoperatively and at selected intervals postoperatively. Despite randomization, patients with more respiratory depression were assigned to nalbuphine. There appeared to be a reversal of respiratory depression with nalbuphine, indicated by a fall in the resting PETCO2 value. This apparent reversal of respiratory depression was associated with a significant increase in pain, requiring treatment in three patients. We conclude that low-dose nalbuphine is not an acceptable method of antagonism of respiratory depression in this group of patients. Many patients who did not receive nalbuphine were able to breathe adequately at an earlier stage than was previously suspected. Close monitoring of the respiratory system may permit earlier extubation without the requirement of a narcotic antagonist after this dose of fentanyl.     

Randomized comparison between sevoflurane anaesthesia and unilateral spinal anaesthesia in elderly patients undergoing orthopaedic surgery

BACKGROUND AND OBJECTIVE: This prospective, randomized study was conducted to compare unilateral spinal block using small doses of hyperbaric bupivacaine and single-agent anaesthesia with sevoflurane in elderly patients undergoing hip surgery. METHODS: Thirty patients (> 65 yr) undergoing hip fracture repair were randomly allocated to receive unilateral spinal anaesthesia with hyperbaric bupivacaine 7.5 mg 0.5% (Group Spinal, n = 15) or volatile induction and maintenance anaesthesia with sevoflurane (Group SEVO, n = 15). General anaesthesia was induced by increasing the inspired concentration to 5%. A laryngeal mask airway was placed without muscle relaxants, and the end-tidal concentrations of sevoflurane were adjusted to maintain cardiovascular stability. Hypotension (decrease in systolic arterial pressure > 20% from baseline), hypertension or bradycardia (heart rate < 50 beats min(-1)) requiring treatment, and the length of stay in the postanaesthesia care unit was recorded. Cognitive functions were evaluated the previous day, and 1 and 7 days after surgery with the Mini Mental State Examination test. RESULTS: Hypotension occurred in seven patients of Group Spinal (46%) and in 12 patients of Group SEVO (80%) (P = 0.05). Phenylephrine was required to control hypotension in three spinal patients (21%) and four SEVO patients (26%) (n.s.). SEVO patients had lower heart rates than spinal patients from 15 to 60 min after anaesthesia induction (P = 0.01). Bradycardia was observed in three SEVO patients (22%). Discharge from the postanaesthesia care unit required 15 (range 5-30) min in Group Spinal and 55 (15-80) min in Group SEVO (P = 0.0005). Eight patients in Group Spinal (53%) and nine patients in Group SEVO (60%) showed cognitive decline (Mini Mental State Examination test decreased > or = 2 points from baseline) 24 h after surgery (n.s.). Seven days after surgery, confusion was still present in one patient of Group Spinal (6%) and in three patients of Group SEVO (20%) (n.s.). CONCLUSIONS: In elderly patients undergoing hemiarthroplasty of the hip, induction and maintenance with sevoflurane provide a rapid emergence from anaesthesia without more depression of postoperative cognitive function compared with unilateral spinal anaesthesia. This technique represents an attractive option when patient refusal, lack of adequate co-operation or concomitant anticoagulant therapy contraindicate the use of spinal anaesthesia.     

Propofol anaesthesia in paediatric ambulatory patients: a comparison with thiopentone and halothane

The purpose of this study was to evaluate the haemodynamic changes during induction, as well as the speed and quality of recovery when propofol (vs thiopentone and/or halothane) was used for induction and maintenance of anaesthesia in paediatric outpatients. One hundred unmedicated children, 3–12-yr-old, scheduled for ambulatory surgery were studied. The most common surgical procedures performed were eye muscle surgery (42%), plastic surgery (21%), dental restoration (15%), and urological procedures (15%). The children were randomized to an anaesthetic regimen for induction/maintenance as follows: propofol/propofol infusion; propofol/halothane; thiopentone/halothane; halothane for both induction and maintenance. Succinylcholine 1.5 mg · kg^?1 was used to facilitate tracheal intubation and N₂O/O₂ were used as the carrier gases in each case. All maintenance drugs were titrated according to the clinical response of the patient to prevent movement and/or maintain BP ± 20% of baseline. Two patients (4%) who received propofol expressed discomfort during injection. The mean propofol dose required to prevent movement was 267 ± 83 μg · kg^?1 · min^?1. The overall pattern of haemodynamic changes, as well as awakening (extubation) times were not different among the four groups. Children who received propofol recovered faster (22 vs 29–36 min) (P < 0.05), were discharged home sooner (101 vs 127–144 min) (P < 0.05), and had less postoperative vomiting (4 vs 24–48%) (P < 0.05) than all others. There were no serious complications or adverse postoperative sequelae in any of the patients in the study. It is concluded that induction and maintenance of anaesthesia with propofol is a well-tolerated anaesthetic technique in children, and is associated with faster recovery and discharged as well as less vomiting than when halothane is used.     

Propofol and alfentanil total intravenous anaesthesia: a comparison of techniques for major thoracic surgery

Background : Previous work has highlighted the disadvantages of propofol as a sole agent for total intravenous anaesthesia (TIVA). This randomised study investigated three combinations of propofol and alfentanil as TIVA for major thoracic surgery.
Methods : In 73 patients undergoing elective thoracic surgery, anaesthesia was conducted either with sodium thiopentone induction and inhalational maintenance (incorporating isoflurane) or with TIVA using propofol with alfentanil (by infusion at one of two rates or in incremental doses). Vital signs and recovery characteristics were recorded.
Results : There were no significant differences in heart rate or blood pressure between groups during either induction or maintenance. Depth of anaesthesia was controlled satisfactorily in all groups. Recovery characteristics were similar between treatment groups, although there was a trend towards earlier orientation
Conclusion : Continuous infusions of propofol and alfentanil provide safe and reliable TIVA for major thoracic surgery. TIVA was found to be a satisfactory technique in more elderly patients than previously described. The higher of the two alfentanil infusion rates may result in a better combination of propofol and alfentanil with respect to recovery times than the lower.     

Comparison of alfentanil, fentanyl and sufentanil for total intravenous anaesthesia with propofol in patients undergoing coronary artery bypass surgery

We have studied the pharmacokinetics and pharmacodynamics ofalfentanil, fentanyl and sufentanil together with propofol inpatients undergoing coronary artery bypass graft surgery (CABG).Sixty patients (age 40–73 yr, 56 male) were assignedrandomly to receive alfentanil, fentanyl or sufentanil and propofol.Plasma concentrations of these drugs and times for the plasmaconcentration to decrease by 50% (t₅₀) and 80% (t₈₀) after cessationof the infusion were determined. Times were recorded to awakeningand tracheal extubation. Total dose and plasma concentrationsof propofol were similar in all groups. Mean total doses ofalfentanil, fentanyl and sufentanil were 443, 45 and 4.4 µg kg^–1,respectively. Time to awakening did not differ significantly.In patients receiving fentanyl, the trachea was extubated onaverage 2 h later than in those receiving sufentanil and3 h later than in those receiving alfentanil (P<0.05).The t₈₀ of fentanyl was longer (P<0.05) than that of alfentanilor sufentanil, and there was a linear correlation between thet₈₀ of the opioid and the time to tracheal extubation (r=0.51;P<0.01). However, the t₅₀ values for these opioids were similarand did not correlate with recovery time. In conclusion, patientsundergoing CABG and who were anaesthetized with fentanyl andpropofol needed mechanical ventilatory support for a significantlylonger time than those receiving alfentanil or sufentanil andpropofol. On the basis of the interindividual variation observed,the time to tracheal extubation was most predictable in patientsreceiving alfentanil and most variable in patients receivingfentanyl, a finding which may be important if the patients aretransferred to a step-down unit on the evening of the operation. Br J Anaesth 2000; 85: 533–40. ^* Corresponding author: Department of Anaesthesia, Helsinki UniversityHospital, PO Box 340, FIN-00029 Hus, Finland     

A randomized doubleblind comparison of fentanyl and sufentanil anaesthesia for coronary artery surgery

Using a randomized double-blind protocol the authors compared two narcotic anaesthetic regimens in 33 patients with good ventricular function undergoing coronary artery surgery. After premedication with morphine and scopolamine, patients received either fentanyl 100 μg.kg^-1 (n = 16), or sufentanil 15 μg.kg^-1 (n = 17), intravenously (IV) over 10 min to induce anaesthesia. Metocurine 0.42 mg kg^-1 provided muscle relaxation. No further IV anaesthetic agents were given. The haemodynamic response to induction, intubation, and surgery, differed minimally between agents. The degree of rigidity on induction was identical with both agents, as were the intervals following induction at which patients lost consciousness, regained consciousness, or met criteria for extubation. However, the interval until extubation criteria were met did correlate with the duration of cardiopulmonary bypass. Sufentanil 15 μg.kg^-1, was clinically indistinguishable from fentanyl 100 μg.kg^-1, when used as the primary anaesthetic agent for coronary surgery.     

A comparison of sub-Tenon's with peribulbar anaesthesia in patients undergoing sequential bilateral cataract surgery

The aim of this study was to compare efficacy and particularly patient preference of sub-Tenon's anaesthesia with peribulbar anaesthesia in patients undergoing sequential, bilateral, cataract surgery. Fifty patients were randomised to either sub-Tenon's or peribulbar anaesthesia for their first operation and the alternative technique for their subsequent operation. Intra-ocular pressure was measured, globe and lid akinesia were scored, patients completed a visual rating score of injection and operative pain and their preference for anaesthesia was assessed. Intra-ocular pressure rose significantly following peribulbar injection (p = 0.02) but was comparable at 5 min. There was no significant difference in lid or globe movement. Injection and operative pain scores were low and comparable. Both methods provided similar anaesthesia and akinesia. The majority (86%) chose the method they received first irrespective of whether it was sub-Tenon's or peribulbar, but 10% of patients preferred sub-Tenon's, disliking the facial numbness from peribulbar anaesthesia.     

A comparison of fentanyl and sufentanil in patients undergoing coronary artery bypass graft surgery

OBJECTIVE: To compare fentanyl and sufentanil, administered in equipotent concentrations by target-controlled infusion, as components of a balanced anesthetic in patients undergoing coronary artery bypass graft (CABG) surgery. DESIGN: A prospective, randomized, double-blind trial. SETTING: A university hospital. PARTICIPANTS: Twenty-one patients undergoing nonemergent, primary CABG surgery. INTERVENTIONS: Patients received fentanyl (group F, n = 10) or sufentanil (group S, n = 11) by target-controlled infusion throughout the pre-cardiopulmonary bypass (CPB) period. To ensure equipotency, the target effect-site concentrations employed (fentanyl, 8.1 ng/mL, and sufentanil, 0.68 ng/mL) were equal to the IC50 for electroencephalographic effect. Isoflurane was administered as needed to maintain pre-CPB hemodynamics near preoperative baseline values. MEASUREMENTS AND MAIN RESULTS: Hemodynamics and end-tidal isoflurane concentration were measured every 15 to 30 seconds. Serum opioid concentrations were measured 5 times between induction and CPB. Opioid cost was based on the number of ampules opened to provide the administered dose. The 2 groups were similar demographically. The pre-CPB serum opioid concentrations were constant and averaged fentanyl, 5.8 +/- 1.9 ng/mL, and sufentanil, 0.59 +/- 0.13 ng/mL. Pre-CPB hemodynamics were stable and similar in both groups. Pre-CPB end-tidal isoflurane requirements did not differ between groups and averaged 0.46 +/- 0.21% in group F and 0.56 +/- 0.24% in group S. The duration of post-operative endotracheal intubation was 9.1 +/- 5.0 hours in group F and 8.0 +/- 3.2 hours in group S (p = NS). The cost per patient of fentanyl (Canadian $6.12 +/- 1.04) was less than that of sufentanil (Canadian $17.47 +/- 4.65). CONCLUSIONS: When administered in a constant 10:1 concentration ratio, fentanyl and sufentanil do not differ in their ability to facilitate pre-CPB hemodynamic control. Although both opioids were relatively inexpensive, the acquisition cost of fentanyl was less than sufentanil. A recommendation regarding the opioid of choice for routine use in patients undergoing CABG surgery awaits more rigorous studies of recovery and cost after equipotent doses of fentanyl and sufentanil. When combined with isoflurane, effect-site opioid concentrations near the IC50 for electroencephalographic effect provide excellent pre-CPB hemodynamic control in patients undergoing CABG surgery.