Comparison of propofol and methohexital for dental and maxillofacial surgery

A prospective study has been undertaken to compare a new intravenous anaesthetic agent, propofol, to methohexitone in 40 ASA I or II patients aged between 18 and 50 years undergoing maxillo-facial surgery and divided into two groups. Intramuscular premedication was standardized for all patients. In group I, propofol 2 mg X kg-1 was injected over 1 min in a peripheral venous line with fentanyl 0.86 microgram X kg-1, followed by an infusion of propofol 5 mg X kg-1 X h-1 and fentanyl 3 micrograms X kg-1 X h-1. In group II, the fentanyl dosage was the same as in group I, whilst methohexitone 3 mg X kg-1 was given for induction and 4.5 mg X kg-1 X h-1 for maintenance of anaesthesia. The following were recorded during induction, maintenance and recovery; haemodynamic parameters using a non invasive method; respiratory parameters; quality of anaesthesia; side-effects. Statistical analysis was performed using the Student t test and qualitative analysis using the Schwartz comparison test at 2%. The following results were found: the quality of anaesthesia with propofol was superior to that of methohexitone during the three stages of anaesthesia. The duration of induction was similar in both groups, but the quality of induction (occurrence of more minor side-effects; p less than 0.05) and intubation was in favour of propofol (p less than 0.05). During maintenance, stability of anaesthesia and a lesser incidence of side-effects were again in favour of the propofol group, in which a slower rate was also found (p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)     

Propofol versus propanidid for the conduction of suspension laryngoscopy

Forty patients who where to undergo suspension laryngoscopy were randomly assigned to two groups, the first receiving 1 microgram . kg-1 fentanyl and a bolus of 2.5 mg . kg-1 propofol followed by 5 to 10 mg . kg-1 . h-1 propofol infusion, and the second 1 microgram . kg-1 fentanyl and 0.2 mg . kg-1 flunitrazepam with 8 mg . kg-1 propanidid in a bolus followed by 40 to 50 mg . kg-1 propanidid infusion. The following parameters were studied: length of apnoea, quality of anaesthesia, the time between stopping giving the anaesthetic and the moment when the patient opens the eyes, gives his name and date of birth, the heart rate, the systolic, diastolic and mean blood pressures, blood gases, before induction, during suspension and at stopping the infusion. Anaesthetic quality was the same for both protocols, and the variations of the haemodynamic parameters were very similar for both groups. Apnoea lasted twice as long with propofol as with the flunitrazepam-propanidid association (p less than 0.001), whereas recovery was twice as quick (p less than 0.001). This seemed to confirm that propofol is better indicated for this type of surgery than the previously used flunitrazepam-propanidid association.     

Sedation with propofol and fentanyl in patients under intensive care]

This study investigated the efficacy of a constant rate infusion of propofol and fentanyl in thirty patients requiring artificial ventilation for more than 24 h. A loading dose, which differed according to the patient's age, was administered over a 30 min period: 2.5 mg.kg-1 for patients less than 50 (G1) (n = 9), 2 mg.kg-1 for patients between 50 and 60 years old (G2) (n = 9), and 1.5 mg.kg-1 for patients over 60 (G3) (n = 12). This was followed by an infusion of 3 mg.kg-1.h-1 in G1 and G2, and 2 mg.kg-1.h-1 in G3. A 1 microgram.kg-1.h-1 infusion of fentanyl was also given. The degree of sedation was assessed with the Ramsay scale before starting, after induction, and every four hours thereafter. When this proved to be insufficient, the dose of propofol was increased by 0.5 mg.kg-1.h-1 as well as that of fentanyl by 0.5 microgram.kg-1.h-1. Heart rate, mean arterial blood pressure, blood propofol, creatinine, transaminase and lipid levels, and urine output were measured before, during, and after the infusion. The blood propofol level increased during the infusion, being correlated to the doses given (r = 0.64, p less than 0.001). Sedation lasted 91.7 +/- 57.7 h. After stopping the infusion of propofol, mean recovery times were 7.5 +/- 5.9 min (G1), 11.4 +/- 11.4 min, and 14.4 +/- 13.5 min (G3) (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)     

Propofol in urological endoscopy in elderly patients. Comparison with methohexital

Twenty patients undergoing cystoscopy (group A) and forty patients undergoing transurethral resection (group B), aged more than 65 years, were anaesthetized. Duration of anaesthesia was less than 15 min for cystoscopy, and more than 30 min for transurethral resection. No premedication was given. The patients were ASA I or ASA II. Group A patients were allocated randomly to receive either 1.5 mg . kg-1 propofol (n = 10) or 2 mg . kg-1 methohexitone (n = 10) for induction of anaesthesia. Anaesthesia was maintained using incremental doses of propofol or methohexitone and 60% N2O with a face-mask. Forty group B patients undergoing transurethral resection were randomly assigned to four equal groups (PB: propofol 1.5 mg . kg-1; MB: methohexitone 2 mg . kg-1; PF: propofol and 1.5 micrograms . kg-1 fentanyl; PFV: propofol, 2 micrograms . kg-1 fentanyl and 0.1 mg . kg-1 vecuronium). Suxamethonium (1 mg . kg-1; groups PB, MB and PF) and vecuronium (0.1 mg . kg-1; group PFV) were given to facilitate endotracheal intubation. Anaesthesia was maintained by infusion of propofol or methohexitone, using a calibrated pump started immediately after intubation. Ventilation was controlled only in group PFV. Induction with 1.5 mg . kg-1 propofol resulted in stopping counting after 62 s and loss of the eye-lash reflex after 84 s versus 47 and 67 s respectively with methohexitone. The anaesthesist's assessment was favourable for cystoscopy with propofol and methohexitone; recovery times were similar for the two drugs in cystoscopy lasting less than 30 min.(ABSTRACT TRUNCATED AT 250 WORDS)     

Influence of bispectral index monitoring on fentanyl requirements during total intravenous anesthesia for major gynecological surgery]

OBJECTIVE: To determine the influence that bispectral index (BIS) monitoring of hypnosis might have on need for analgesia during surgery under total intravenous anesthesia provided by bolus administration of fentanyl. PATIENTS AND METHOD: Prospective, randomized and partially double-blind study of 40 patients undergoing major gynecological surgery under total intravenous anesthesia with propofol and fentanyl. In the BIS group (n = 20) propofol administration was adjusted to maintain BIS between 40 and 60. In the control group (n = 20) standard doses were given: 10 mg/kg-1/h-1 after anesthetic induction and for 5 minutes, 8 mg/kg-1/h-1 over the next 5 minutes and 6 mg/kg-1/h-1 throughout the rest of the operation. All patients received intravenous bolus administration of 150 or 75 microg of fentanyl to maintain analgesia whenever systolic blood pressure and heart rate increased 20% over baseline. We compared propofol and fentanyl requirements, intraoperative changes in BIS, and awakening from anesthesia. RESULTS: Patient and surgical characteristics were similar in both groups. BIS monitoring allowed propofol administration to be decreased a mean 24% during maintenance of anesthesia, and this in turn was associated with a significant increase in mean dose of fentanyl (415 microg versus 253 microg in the BIS and control groups, respectively; p = 0.01). Mean values of BIS were higher in the BIS group (46.4 versus 42.2; p = 0.04) and patients in the BIS group awoke sooner (in 7.7 min versus 11.1 min; p = 0.01) and tended to report less pain upon arrival at the postanesthetic recovery room, although the difference was not statistically significant. CONCLUSIONS: BIS monitoring of depth of hypnosis can influence requirements for fentanyl during total intravenous anesthesia by bolus dosing for maintenance of analgesia. This is probably due to changes in the administration of propofol made possible by BIS monitoring.     

Total intravenous anaesthesia with propofol or etomidate

In combination with fentanyl, propofol was compared with etomidate for total intravenous anaesthesia in 21 women (ASA Grades I-II) admitted for elective hysterectomy. They received either propofol (bolus 1.5 mg kg-1, infusion 9 mg kg-1 h-1 for 10 min thereafter 6 mg kg-1 h-1) or etomidate (bolus 0.10 mg kg-1, infusion 3 mg kg-1 h-1 reduced to 0.6 mg kg-1 h-1). Fentanyl 10 micrograms kg-1 was given for induction followed by an infusion of 30 micrograms kg-1 h-1 for 10 min reduced to 6 micrograms kg-1 h-1 for the first hour and successively reduced over time. Induction was smooth and maintenance easy to manage in both groups. There was no difference in time from end of infusion until extubation, but the time until the patients could report their date of birth was significantly shorter in the propofol group. Nausea and vomiting were more pronounced in the etomidate group, and mental side-effects were only seen after etomidate. After 3 months, more patients in the etomidate group complained of reduced power of concentration. We conclude that total intravenous anaesthesia with either propofol or etomidate is equally easy to manage, but in the recovery situation propofol was advantageous in time and quality.     

Effects of propofol on intraocular pressure in surgery of strabismus in children

Propofol was assessed for eye surgery in 20 children. ASA group I or II, 2-14 year-old, randomly assigned to 2 equal groups. Premedication, analgesia and muscle paralysis were similar in both groups. Group P patients were given an induction dose of 4 mg.kg-1 propofol, followed by an infusion of 15 mg.kg-1.h-1 for the first half hour, and then 10 mg.kg-1.h-1 to maintain anaesthesia. Group C patients were given 10 mg.kg-1 thiopentone for induction and halothane for maintenance. The quality of anaesthesia was assessed by monitoring adverse effects, heart rate, blood pressure, the length of anaesthesia, the delay of the first spontaneous breath and eye opening, and extubation. Intraocular pressure was measured before and 3 min after intubation, and 5 min after extubation. The quality of anaesthetic induction and maintenance were very similar in both groups. Pain occurred more frequently at the injection site with propofol (p less than 0.01). Children in group P recovered more quickly, and extubation was possible much earlier in this group (p less than 0.05). However, restlessness was significantly more frequent in group P (n = 9) than in group C (n = 1) (p less than 0.01). Systolic, diastolic blood pressure and heart rate were significantly lower in group P (p less than 0.05; 0.001; 0.001 respectively). No significant decrease in intraocular pressure in both groups was observed. The use of propofol for eye surgery in children is acceptable, despite some restlessness during recovery.     

Recovery after anesthesia with propofol in otorhinolaryngologic surgery of brief duration

This study was designed to assess recovery from total intravenous anaesthesia with propofol for short ENT procedures. Twenty-six patients (ASA I and II) were assigned to two groups of thirteen: one breathed air (Laser laryngeal microsurgery), the second N2O-O2 (FIO2 : 0.5) (various ENT procedures). The induction sequence was exactly the same for both groups: oral premedication with 10 mg diazepam one hour before surgery, I mg pancuronium bromide, 2 micrograms X kg-1 fentanyl, denitrogenation within 3 min, after which propofol was delivered (2.5 mg X kg-1). When the eye-lash reflex had disappeared (time recorded), 1.5 mg X kg-1 suxamethonium was given and laryngotracheal intubation carried out. A continuous infusion of propofol (9 mg X kg-1 X h-1) was started. Surgery began 5 +/- 2 min after the start of propofol infusion. The durations of anaesthesia, surgery and propofol infusion were similar in both groups. To have good surgical conditions, it was necessary to give repeated doses of propofol for 15 patients. Thus, the total dose of propofol was significatively different between the two groups: 24.5 +/- 6.7 mg X kg-1 X h-1 in group "air" versus 16 +/- 3.6 mg X kg-1 X h-1 in group "N2O-O2" (p less than 0.001). Extubation occurred within 16 +/- 8 min in group "air", being more rapid in group "N2O-O2" (11 +/- 9 min; no significant difference). Recovery was assessed with two psychomotor tests: choice reaction time (CRT) and tracing test (TT).(ABSTRACT TRUNCATED AT 250 WORDS)     

Comparison of propanidid with propofol for dental surgery of short or medium duration

The properties of propofol in emulsion given by continuous intravenous infusion to spontaneously breathing patients have been well studied. Thirty randomized voluntary premedicated patients undergoing dental extraction were anaesthetized with propofol (2.5 mg X kg-1 IVD, and 9 mg X kg-1 X h-1) or with propanidid (9 mg X kg-1 IVD, and 60 mg X kg-1 X h-1), supplemented with nitrous oxide in oxygen and fentanyl. Induction, maintenance and recovery times had the same characteristics. Highly significant differences occurred between the two groups regarding the increase in heart rate, apnoea and recovery time. This study showed that propofol was an eminently suitable agent for continuous intravenous anaesthesia in spontaneously breathing patients for dental surgery.     

Effects of propofol and isoflurane on the neuromuscular block induced by atracurium]

Speed of onset, duration of action and recovery time for a bolus injection of atracurium were measured in two groups of patients. In group I anaesthesia considered of propofol, fentanyl, nitrous oxide and oxygen mixture. The induction dose of propofol was 2 mg/kg-1 followed by an infusion of 9.0 mg/kg-1/h-1 for first half hour and 4.5 mg/Kg-1/h-1 subsequently. In group II anaesthesia consisted of isoflurane, fentanyl, nitrous oxide and oxygen mixture. Isoflurane was given upon clinical needs. Speed of onset, duration of action, and recovery time for atracurium were measured in the two groups. No statistically significant differences between speed of onset and duration of action between the two groups were found. The recovery period from T1 = 10% to T1 = 70% twitch response was considerably longer with isoflurane (25 min +/- 6) than with propofol (18 min +/- 3) (p less than 0.01). Results obtained suggest that for adequate relaxation during tracheal intubation smaller doses of atracurium are not needed during isoflurane than propofol administration. Because of the longer recovery period of residual neuromuscular blockade during isoflurane anaesthesia decreasing doses of atracurium and careful monitoring of twitch depression tension are also suggested.     

The effect of pre-induction glycopyrronium on the haemodynamic response of elderly patients to anaesthesia with propofol

This study investigated whether pretreatment with glycopyrronium can attenuate the hypotension caused by anaesthesia of the elderly with propofol. Twenty elderly patients (77.1 +/- 2.44 years, mean +/- SEM) of ASA physical status 2 or 3 scheduled for elective urological procedures were given glycopyrronium 0 (n = 10) or 5 micrograms.kg-1 (n = 10) in a randomised, double-blind manner, 5 min before induction of anaesthesia with propofol infused at 600 ml.h-1 (average induction dose 1.7 +/- 0.06 mg.kg-1, mean +/- SEM) followed by maintenance with a propofol infusion at 10 mg.kg-1.h-1. Although glycopyrronium significantly increased heart rate (p less than 0.01, ANOVA), the decrease in blood pressure 2 and 5 min after induction was similar in both groups. The study had a power of 80% to detect a 20 mmHg difference in systolic arterial pressure between treatment groups with p less than 0.05.     

Anaesthesia for myocardial revascularisation

We studied the effects on myocardial performance and metabolism of fentanyl/propofol and fentanyl/enflurane anaesthesia in 20 patients before coronary artery bypass grafting. Anaesthesia was induced with fentanyl 20 micrograms.kg-1 and pancuronium 0.15 mg.kg-1. Patients received, by random allocation, either propofol by infusion, 6 mg.kg-1.h-1 reduced by half after 10 min then adjusted as necessary (mean rate 2.8 mg.kg-1.h-1), or enflurane 0.8% inspired concentration for 10 min reduced to 0.6% and adjusted as required (mean 0.7%). Measurements were made before induction, after tracheal intubation, after skin incision and after sternotomy. There were no significant differences between the groups in any haemodynamic variables during the study. Following intubation both groups showed a rise in heart rate (p < 0.01) and cardiac index (p < 0.05). Systemic vascular resistance decreased after intubation (p < 0.05) then returned to baseline during surgery; stroke index was unchanged after intubation but was reduced during surgery (p < 0.01) as systemic vascular resistance increased. Regional and global coronary blood flow were maintained in both groups, as were myocardial oxygen consumption and lactate extraction ratio. However, lactate production did occur in one patient receiving enflurane and Holter monitoring confirmed ischaemia. One patient receiving propofol showed lactate production not accompanied by any ECG changes. This study suggests that propofol may be a suitable alternative to enflurane as an adjunct to opioids in anaesthesia for coronary artery bypass grafting.     

A comparison of spinal anesthesia with small-dose lidocaine and general anesthesia with fentanyl and propofol for ambulatory prostate biopsy procedures in elderly patients

STUDY OBJECTIVE: To compare operating conditions, intraoperative adverse events, recovery profiles, postoperative adverse effects, patient satisfaction, and costs of small-dose lidocaine spinal anesthesia with those of general anesthesia using fentanyl and propofol for elderly outpatient prostate biopsy. DESIGN: Prospective, randomized, blind study. SETTING: Outpatient anesthesia unit at a municipal hospital. PATIENTS: 80 ASA physical status I and II patients, aged 65 to 80 years, scheduled for outpatient prostate biopsy. INTERVENTIONS: Patients were assigned to receive either spinal anesthesia with 10 mg of hyperbaric 1% lidocaine (L group, n=40) or anesthetic induction with fentanyl 1 microg.kg-1 IV and 1.0 mg.kg-1 propofol injected at 90 mg.kg-1.h-1, followed by continuous infusion at 6 mg.kg-1.h-1 (F/P group, n=40). MEASUREMENTS AND MAIN RESULTS: Both anesthetic techniques provided acceptable operating conditions for the surgeon. However, a significantly higher frequency of intraoperative hypotension was found in the F/P group than in the L group (P<0.05). Time to home readiness was shorter in the F/P group (P<0.05). Both techniques had no major postoperative adverse effects and resulted in a high rate of patient satisfaction. Total costs were significantly lower in the L group than in the F/P group (P<0.01). CONCLUSIONS: Spinal anesthesia with 10 mg of hyperbaric 1% lidocaine may be a more suitable alternative to general anesthesia with fentanyl and propofol for ambulatory elderly prostate biopsy in terms of safety and costs.     

Propofol auto-co-induction as an alternative to midazolam co-induction for ambulatory surgery

We propose the use of an intravenous propofol/propofol auto-co-induction technique as an alternative to propofol/midazolam for induction of anaesthesia. We have studied 54 unpremedicated ASA 1 or 2 patients undergoing day-stay anaesthesia for minor orthopaedic surgery. All received 10 micrograms.kg-1 or alfentanil before induction, followed by either midazolam 0.05 mg.kg-1, propofol 0.4 mg.kg-1 or saline, and 2 min later, a propofol infusion at a rate of 50 mg.kg-1.h-1 until loss of eyelash reflex. We compared pre- and postinduction haemodynamic changes, complications at insertion of a laryngeal mask airway and recovery from anaesthesia in the three groups. Both co-induction techniques showed less postinduction hypotension and significant reduction of the total induction dose of propofol when compared to the control group. In the propofol/propofol group there was a decreased incidence of apnoea during induction of anaesthesia. These patients were discharged from hospital 2 h after the end of anaesthesia whereas patients in the midazolam/propofol group were discharged after 2 1/2 h (p < 0.001).     

Sedation for bronchofiberoscopy: comparison between propofol infusion and intravenous boluses of fentanyl and diazepam

Two methods of sedation were evaluated in unpremedicated patients undergoing elective bronchofiberoscopy. The patients were randomly allocated to receive either propofol infusion 1 mg kg-1 h-1 preceded by a 1 mg kg-1 bolus (15 patients) (the propofol group) or intravenous fentanyl 1 micrograms kg-1 and diazepam 0.05 mg kg-1 (15 patients) (the fentanyl+diazepam group). Thirteen patients were treated twice during the study period and sedated with both methods (the first treatment according to random order and the second with the method not used on the first occasion). A topical anaesthetic was applied to the selected nostril with two cotton swabs soaked in 4% lidocaine. Epiglottis, vocal cords, trachea and bronchi were anaesthetized by spraying 4% lidocaine through the working channel of the fiberoscope as the instrument was advanced. The patients in the propofol group were more sedated than those in the fentanyl+diazepam groups (P less than 0.01). The working conditions were the same. After sedation, respiratory frequency decreased only in the fentanyl+diazepam group (P less than 0.05). Before sedation, haemoglobin saturation of oxygen was 95 +/- 2% (mean +/- s.d.) in the propofol group and 94 +/- 3% in the fentanyl+diazepam group. Immediately before the start of bronchofiberoscopy, it was 89 +/- 4% and 90 +/- 3%, respectively. The decrease was statistically significant in both groups (P less than 0.001). After sedation, systolic arterial pressures (SAP) decreased in both groups (P less than 0.01). Compared to values immediately before starting bronchofiberoscopy, SAP increased during the procedure in both groups (P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)     

Randomized comparison of recovery after propofol-nitrous oxide versus thiopentone-isoflurane-nitrous oxide anaesthesia in patients undergoing ambulatory surgery

A randomized, prospective study was performed to compare recovery characteristics in 41 ASA physical status I-II patients scheduled for ambulatory surgery with either propofol or thiopentone-isoflurane anaesthesia. Particular attention was focused on the recovery time needed to meet discharge criteria. The propofol group received propofol 2 mg.kg-1 for induction followed by propofol infusion (6-9 mg.kg-1.h-1) 1 min after intubation. The thiopentone-isoflurane group received thiopentone 4 mg.kg-1 for induction followed by isoflurane (0.5-2%) 1 min after endotracheal intubation. Other drugs administered during or after anaesthesia were similar between the groups. The propofol group had significantly (P less than 0.05) faster clinical recovery than the isoflurane group with respect to times to response to commands, eye opening, orientation, ability to stand and void, tolerance to oral fluids, "home-readiness", and recovery of perceptual speed. Patients in the propofol group had significantly less (P less than or equal to 0.05) emesis than the patients given isoflurane. We conclude that in patients undergoing ambulatory surgery propofol infusion is preferable to thiopentone-isoflurane anaesthesia, because it may allow faster discharge home.     

Recovery and discharge of patients after long propofol infusion vs isoflurane anaesthesia for ambulatory surgery

Fifty unpremedicated patients scheduled for outpatient restorative dentistry and/or oral surgery lasting 2 to 4 h were anaesthetized with either propofol infusion or isoflurane inhalation. Before induction of anaesthesia with propofol (2.5 mg.kg-1), all patients were given 75 mg of diclofenac and 0.01 mg.kg-1 vecuronium intravenously. Intubation was facilitated with suxamethonium (1.5 mg.kg-1) and anaesthesia was maintained in random order either with propofol infusion (12 mg.kg-1.h-1 for the first 20 min, 9 mg.kg-1.h-1 for the next 20 min, and 6 mg.kg-1.h-1 for the rest of the anaesthesia) or with isoflurane (inspired concentration 1-2.5%), both with nitrous oxide and oxygen (30%). The patients breathed spontaneously using a non-rebreathing circuit. Patients given propofol infusion became re-orientated faster (11.0 +/- 5.5 min vs. 16.5 +/- 7.5 min; P less than 0.01) and at 30 min walked along a straight line better (P less than 0.01). At 60 min, none of the propofol patients displayed an unsteady gait, whereas 11 of the 25 isoflurane patients did (P less than 0.001). None of the patients receiving propofol had emesis at the clinic, compared with 10 of the 25 patients receiving isoflurane (P less than 0.001). The overall incidence of emesis was 2 of 25 and 14 of 25 in the propofol and isoflurane groups, respectively (P less than 0.01). Patients receiving propofol were discharged home earlier than patients receiving isoflurane (80 +/- 14 min and 102 +/- 32 min, respectively; P less than 0.01). It is concluded that propofol allows early discharge of patients, even after long anaesthesias.     

A comparison of anaesthetic techniques for shock wave lithotripsy: the use of a remifentanil infusion alone compared to intermittent fentanyl boluses combined with a low dose propofol infusion

This study examined the intra-operative and postoperative characteristics of a remifentanil infusion alone, or intermittent fentanyl bolus admistration combined with a propofol infusion, for the anaesthetic management of patients undergoing shock wave lithotripsy. One of the key parameters investigated was the time to discharge. Fifty patients scheduled for extracorporeal shock wavelithotripsy (ESWL) were randomly allocated to receive either a continuous infusion of 0.2-0.4 micro g.kg-1.min-1 of remifentanil (Group 1) or a bolus of 3 micro g.kg-1 fentanyl followed by a continuous infusion of propofol at a rate of 2 mg.kg-1.h-1 with additional boluses of 0.05 mg fentanyl administered as required (Group 2). Both anaesthetic techniques were found to provide satisfactory analgesia and intra-operative conditions for ESWL. However, patients in the remifentanil Group 1 showed a higher incidence of nausea (52% vs. 0%, p < 0.01) and retching (36% vs. 0%, p < 0.01) 120 min following ESWL compared to Group 2. This resulted in prolonged discharge times (p < 0.01) in this group. We found that remifentanil used as the sole agent failed to demonstrate any advantage over the combination of fentanyl/propofol with regard to rapid recovery and discharge following anaesthesia for extracorporal shock wave lithotripsy.     

Haemodynamic comparison of propofol-fentanyl anaesthesia with midazolam-fentanyl anaesthesia in CABG patients without preoperative heart failure

This study was designed to compare prebypass haemodynamics under total intravenous anaesthesia (TIVA) using midazolam-fentanyl (group M) and propofol-fentanyl (group P) combinations. Sixteen adult patients undergoing CABG were studied with patients in group M and P (n = 8 each) given intravenous midazolam 0.1 mg.kg-1.h-1 and propofol 4 mg.kg-1.h-1 with fentanyl 25 micrograms.kg-1 until sternotomy, respectively. Following induction of anaesthesia, cardiac index and heart rate decreased significantly (30% and 20% in both groups, p < 0.05) these variables returned to baseline on completion of sternotomy. In addition, in group P mean arterial pressure decreased significantly (about 15%) following induction and there were no ischaemic signs. Overall for MAP there was no significant difference between the two groups. LVSWI and RVSWI were reduced by around 25% in both groups. Only the change in LVSWI reached statistical significance (p < 0.05). This reduction may have exert a caridioprotectant action by decreasing myocardial oxygen consumption. We conclude that both TIVA techniques represent an acceptable anaesthetic regimen for use in cardiac anaesthesia.     

The course of blood concentrations of propofol administered at a constant rate, combined with fentanyl

The blood concentration of propofol was studied in 14 ASA 1 informed patients, who were to undergo orthopaedic or plastic surgery lasting at least 90 min. Anaesthesia was induced with a 2 mg.kg-1 bolus of propofol together with 0.86 microgram.kg-1 fentanyl. This was followed by a constant rate infusion of propofol and fentanyl, 5 mg.kg-1.h-1 and 3 micrograms.kg-1.h-1 respectively. The mean duration of propofol infusion was 153 +/- 63 min, with extremes of 90 and 315 min. Propofol concentration was measured using gas phase chromatography on total arterial blood; the lower limit of detection was 0.05 mg.l-1. During the infusion, blood concentrations were found between 2 and 4 mg.l-1. It was 2.25 mg.l-1 at the fifth min; this was 80% of the concentration found at the 120th min. There was in fact no statistically significant difference between the values found at the 90th, 120th and 150th min. On stopping the infusion, the concentrations fell rapidly during the first 5 min, and then more slowly. By the 30th min, it had reached a value 4.5 times less than that at the end of the infusion. However, individual variations were found, which could explain delayed recovery. The calculated pharmacokinetic parameters were: elimination half-life = 41.7 +/- 20 min, clearance = 2.14 +/- 0.55 l.min-1 and equilibrium distribution volume = 43.4 +/- 15.2 l. These results are discussed. It is therefore possible to give propofol continuously at a constant rate without having any accumulative effect.