Haemodynamic effects of induction of general anaesthesia with propofol during epidural anaesthesia

PURPOSE: To clarify whether propofol administration during thoracic or lumbar epidural anaesthesia intensifies the haemodynamic depression associated with epidural anaesthesia. METHODS: Patients (n = 45) undergoing procedures of similar magnitude were randomly divided into three study groups: a control group (n = 15) receiving general anaesthesia alone and two study groups undergoing thoracic (n = 15) and lumbar epidural anaesthesia (n = 15) before induction of general anaesthesia. All patients received 2 mg.kg-1 propofol at a rate of 200 mg.min-1, followed by a continuous infusion of 4 mg.kg-1.hr-1. Mean arterial blood pressure (MAP) and heart rate (HR) were measured at baseline, three minutes after induction, and one minute after tracheal intubation in all three groups and at 20 min after epidural anaesthesia was established in the thoracic and lumbar groups. RESULTS: Following epidural anaesthesia, MAP decreased from 94 +/- 14 (SD) at baseline to 75 +/- 11 mmHg (P < 0.0001) in the thoracic group and from 92 +/- 12 to 83 +/- 15 mmHg in the lumbar group. After propofol administration, MAP decreased further in the thoracic group to 63 +/- 9 mmHg (P = 0.0077) and to 67 +/- 10 mmHg (P = 0.0076) in the lumbar group. The MAP following propofol induction in the thoracic group (P < 0.0001) and in the lumbar group (P = 0.0001) was lower than MAP in the control group (81 +/- 9 mmHg). HR decreased only in response to thoracic epidural anaesthesia (P = 0.0066). CONCLUSION: The hypotensive effects of propofol are additive to those of epidural anaesthesia, resulting in a profound decrease in mean arterial pressure.     

A comparison of the myocardial metabolic and haemodynamic changes produced by propofol-sufentanil and enflurane-sufentanil anaesthesia for patients having coronary artery bypass graft surgery

The purpose of this study was to compare propofol-sufentanil with enflurane-sufentanil anaesthesia for patients undergoing elective coronary artery bypass graft (CABG) surgery with respect to changes in (1) haemodynamic variables; (2) myocardial blood flow and metabolism; (3) serum cortisol, triglyceride, lipoprotein concentrations and liver function; and (4) recovery characteristics. Forty-seven patients with preserved ventricular function (ejection fraction greater than 40%, left ventricular end diastolic pressure less than or equal to 16 mmHg) were studied. Patients in Group A (n = 24) received sufentanil 0.2 microgram.kg-1 and propofol 1-2 mg.kg-1 for induction of anaesthesia which was maintained with a variable rate propofol (50-200 micrograms.kg-1.min-1) infusion and supplemental sufentanil (maximum total 5 micrograms.kg-1). Patients in Group B (n = 23) received sufentanil 5 micrograms.kg-1 for induction of anaesthesia which was maintained with enflurane and supplemental sufentanil (maximum total 7 micrograms.kg-1). Haemodynamic and myocardial metabolic profiles were determined at the awake-sedated, post-induction, post-intubation, first skin incision, post-sternotomy, and pre-cardiopulmonary bypass intervals. Induction of anaesthesia produced a larger reduction in systolic blood pressure in Group A (156 +/- 22 to 104 +/- 20 mmHg vs 152 +/- 26 to 124 +/- 24 mmHg; P less than 0.05). No statistical differences were detected at any other time or in any other variable including myocardial lactate production (n = 13 events in each group), time to tracheal extubation and time to discharge from the ICU. We concluded that, apart from hypotension on induction of anaesthesia, propofol-sufentanil anaesthesia produced anaesthetic conditions equivalent to enflurane-sufentanil anaesthesia for CABG surgery.     

Comparison of propofol and thiopentone for induction of anaesthesia in premedicated patients

Thirty premedicated ASA I or II patients scheduled for minor gynaecological surgery, were randomly allocated to receive either 1.5 mg/kg or 2 mg/kg propofol of the new emulsion formulation, or 4 mg/kg thiopentone, given over 20 seconds. Anaesthesia was successfully induced in all 30 patients. The mean (SEM) induction times were for propofol 1.5 mg/kg 33.3(3.2) seconds, for 2 mg/kg 30.5(2.7) seconds and for thiopentone 34.6(2.7) seconds. The incidence of apnoea greater than 10 seconds, was respectively 60, 80 and 80%, and the mean duration of apnoea 30.8(5.3), 37.1(5.0) and 23.7(5.0) seconds. The mean systolic blood pressure decreased after propofol 1.5 mg/kg by 16.0 mmHg, after 2 mg/kg by 18.6 mmHg, and increased after thiopentone by 1 mmHg, 2 minutes after injection. Heart rate increased significantly 2 minutes after thiopentone by an average of 15.1 beats/minute, but not after propofol. Pain was not reported during or after the injection. No major adverse reactions occurred at induction or during maintenance of anaesthesia with an inhalation agent. One patient who received 2 mg/kg propofol and isoflurane vomited for 24 hours. The recovery of anaesthesia after propofol induction, was quicker than after thiopentone.     

Timing of midazolam and propofol administration for co-induction of anaesthesia

We aimed to determine the optimum timing of midazolam administration prior to propofol to achieve the maximal reduction in the dose of propofol required to induce anaesthesia. Female (ASA 1-2) patients, aged 18 to 45 years, weighing 40 to 75 kg and scheduled for gynaecological surgery were eligible for the study. Consenting patients were randomly assigned to six groups. Group 1 received saline and Groups 2 to 6 received midazolam 3 mg at 1, 2, 4, 6 or 10 minutes respectively prior to propofol (n = 20 to 22 per group) in a blinded manner. Propofol was administered i.v. over 10 seconds and flushed in with saline 5 ml. Two minutes later, the patient's response to pressure applied to the finger was determined as an index of loss of consciousness. The ED50 of propofol in each group was determined by the up-and-down method. Propofol ED50 was reduced to 34 to 67% (P < 0.001) in the midazolam treated groups. There was no significant (P = 0.14) difference in propofol ED50 among the five groups which received midazolam. Patients who received midazolam had less recollection of events surrounding induction (P < 0.001) and recalled the induction experience as being more pleasant (P = 0.03) than those who did not receive midazolam. These results indicate that midazolam may be given up to 10 minutes prior to propofol and still achieve a substantial dose reduction.     

Intra-operative patient-controlled sedation

Propofol and midazolam were compared for intra-operative patient-controlled sedation in 40 ASA 1 day patients undergoing surgical extraction of third molar teeth under local anaesthesia. All patients initially received 0.7 micrograms.kg-1 fentanyl. Patients in the propofol group self-administered 20 mg (2 ml over 6 s) bolus doses of propofol; successful demands averaged 8.0 (SD 4.4) and unsuccessful demands (during the 1 min lockout period) 2.8 (SD 4.1). The midazolam group self-administered 0.5 mg (2 ml over 6 s) bolus doses and averaged 14.0 (SD 6.3) and 17.6 (SD 19.8) successful and unsuccessful demands respectively. Postoperative memory, measured with delayed free recall, and postoperative mental performance, measured with the frequency accrual speed test index, were both significantly less impaired in the propofol group. Although there was no significant difference in patient satisfaction, measured postoperatively, propofol was judged the more suitable agent for patient-controlled sedation, because of its more rapid response to fluctuating intra-operative requirements, superior recovery characteristics and beneficial effect on mood.     

Disoprivan for the induction and maintenance of short anesthesia

Disoprivan (Propofol) was used for induction and maintenance of anaesthesia for short surgical procedures in non-premedicated and premedicated (0.5 mg atropine, 3 mg midazolam) patients. A dose of 130-150 mg Disoprivan was adequate for induction, and a dose of 72 and of 62 micrograms/kg body weight/min anaesthesia respectively, for maintenance, together with N2O/O2 2:1. The anaesthesia was characterized by an apnoea of 40-60 s duration, a decrease in arterial blood pressure of 20%, a slowing of heart rate in non-premedicated patients by 12 beats/min and a rapid and pleasant recovery with lack of emetic sequelae. Disoprivan is considered useful for this type of anaesthesia.     

Effects of remifentanil and fentanyl on intraocular pressure during the maintenance and recovery of anaesthesia in patients undergoing non-ophthalmic surgery

BACKGROUND AND OBJECTIVE: To compare the effects of remifentanil and fentanyl on intraocular pressure during the maintenance and recovery of anaesthesia in patients undergoing elective non-ophthalmic surgery. METHODS: Thirty-two patients (ASA I-II) were randomized into two groups to receive either a continuous infusion of remifentanil (0.25-0.5 microg kg(-1) min(-1), n =16, Group R) or an intermittent bolus of fentanyl (2-5 microg kg(-1), n = 16, Group F) during the maintenance of anaesthesia. For the induction of anaesthesia, Group R received remifentanil 1 microg kg(-1) and Group F received fentanyl 2 microg kg(-1); both groups then received propofol 2 mg kg(-1) with vecuronium 0.1 mg kg(-1). Anaesthesia in both groups was maintained with a continuous infusion of propofol 4-8 mg kg(-1) h(-1). Ventilation of the lungs was controlled to a constant end-tidal PCO2 of 4.7-5.4 kPa. Blood pressure, electrocardiography, heart rate and oxygen saturation were monitored throughout anaesthesia. Intraocular pressure was determined before surgery, during the maintenance of anaesthesia, 2 min after emergence and in the recovery room using a Perkins hand-held applanation tonometer by an ophthalmologist blinded to the anaesthetic technique. RESULTS: After induction of anaesthesia, a significant decrease in intraocular pressure in the remifentanil group from 13.6 +/- 2.6 to 7.1 +/- 3.1 mmHg (P < 0.001) and in the fentanyl group from 13.7 +/- 2.2 to 9.7 +/- 3.4 mmHg (P < 0.001) was observed and maintained during anaesthesia. Thirty minutes after the end of anaesthesia, intraocular pressure returned to baseline values in both groups (remifentanil: 13.9 +/- 2.8 mmHg, P = 0.28; fentanyl: 13.6 +/- 2.3 mmHg, P = 0.59). The intraocular pressure and haemodynamic variables did not differ significantly between the two groups (intraocular pressure, P = 0.7327; blood pressure, P = 0.1295; heart rate, P = 0.8601). CONCLUSIONS: Remifentanil maintains intraocular pressure at an equally reduced level compared with fentanyl.     

Induction agents for day-case anaesthesia A double-blind comparison of propofol and midazolam antagonised by flumazenil

Early postoperative recovery was studied using sedation scoring, measurement of flicker fusion frequency and completion of Trieger test figures in 60 male patients who presented for vasectomy under general anaesthesia as day patients. Anaesthesia was induced in groups 1 and 2 (20 patients each) with mean (SD) doses of 0.16 (0.04) mg/kg or 0.16 (0.03) mg/kg midazolam respectively; group 2 received flumazenil 0.55 (0.19) mg after completion of surgery. The remaining 20 patients (group 3) received propofol 1.50 (0.24) mg/kg. Anaesthesia was maintained with isoflurane vaporized in 33% oxygen and nitrous oxide in all patients. Flumazenil tended to improve tests of recovery after midazolam anaesthesia, but early recovery after propofol anaesthesia was associated with better psychomotor test results and less impairment of mental state as judged by sedation and amnesia scoring.     

Echocardiographic assessment of the haemodynamic effects of propofol: a comparison with etomidate and thiopentone

The haemodynamic effects of propofol (2 mg/kg), etomidate (0.2 mg/kg) and thiopentone (4 mg/kg) were studied in 30 ASA 1 and 2 patients in whom anaesthesia had been induced with midazolam 0.1 mg/kg, fentanyl 5 micrograms/kg, vecuronium 0.1 mg/kg and atropine 10 micrograms/kg, and maintained with nitrous oxide in oxygen. Arterial pressure was measured directly and left ventricular diameters were determined by transoesophageal echocardiography. Systolic blood pressure after propofol and thiopentone and the end-systolic quotient (systolic pressure/end-systolic diameter), a measure of inotropy, decreased. Fractional shortening (end-diastolic-end-systolic diameter/end-diastolic diameter) decreased only in the thiopentone group. Diastolic blood pressure and end-diastolic diameter (a measure of preload) did not change in any of the groups, and the etomidate group showed no changes in the haemodynamic variables measured. Propofol shows simultaneous negative inotropy and afterload reduction, while thiopentone is exclusively negatively inotropic.     

Venodilation contributes to propofol-mediated hypotension in humans.

The present investigation explored the possibility that the commonly observed hypotension that occurs during induction of anesthesia with propofol might be related to its ability to produce venodilation. Thirty-six ASA I and II patients who received no premedication were studied. The first 20 patients were divided into two equal groups. Hemodynamic measurements consisted of heart rate, arterial blood pressure, and forearm venous compliance by occlusive plethysmography. Baseline measurements were made in awake patients while resting in a supine position. Repeat measurements were made during steady-state infusions of propofol (2.5 mg/kg bolus injection, followed by a continuous infusion at 200 micrograms.kg-1.min-1) or thiopental (4 mg/kg bolus injection, followed by continuous infusion at 200 micrograms.kg-1.min-1), 10 min after tracheal intubation while patients were artificially ventilated. Both anesthetics resulted in a significant (P less than 0.05) and similar tachycardia; however, propofol produced significant decreases in systolic (-30 +/- 9 mm Hg) and diastolic (-11 +/- 4 mm Hg) arterial blood pressure. Forearm venous compliance was significantly increased during propofol administration but unchanged in patients receiving thiopental. In four additional patients receiving smaller consecutive infusions of propofol (50 and 100 micrograms.kg-1.min-1), significant subtle increases in forearm compliance were also recorded. These increases were not observed in four patients who received placebo infusions. Thus, one mechanism promoting hypotension during propofol anesthesia in humans seems to be related to its direct effects on venous smooth muscle tone and presumably venous return.     

Anaesthetic induction with alfentanil: comparison with thiopental, midazolam, and etomidate

The speed, side effects and cardiovascular changes associated with anaesthetic induction and endotracheal intubation following alfentanil (20 micrograms/kg/min, IV), thiopental (84 micrograms/kg/min, IV), etomidate (5 micrograms/kg/min, IV) and midazolam (20 micrograms/kg/min, IV) prior to halothane-nitrous oxide general anaesthesia were evaluated and compared in 80 patients undergoing elective general surgical operations. Anaesthetic induction was fastest with etomidate and thiopental (approximately one minute) and slowest with midazolam (about two minutes). Systolic arterial blood pressure (SBP) was decreased at the moment of unconsciousness with thiopental but unchanged with the other compounds. Heart rate (HR) was increased at unconsciousness with midazolam and thiopental but unchanged with etomidate and alfentanil. After intubation HR was increased in all groups except those induced with alfentanil. Arrhythmias were infrequent (5 per cent or less in all groups). Rigidity during induction only occurred with alfentanil (55 per cent) and pain on injection only with etomidate (35 per cent) and alfentanil (5 per cent). Postoperative vomiting was infrequent in all groups (15 per cent) except etomidate (55 per cent). No patient remembered any aspect of laryngoscopy or the operation and all rapidly regained consciousness at the end of operation. The results of this study demonstrate that with the exception of rigidity (which is easily overcome with succinylcholine) and a slightly slower onset of action, alfentanil compares favourably as an induction agent with thiopental and is better than midazolam and etomidate. Alfentanil is superior to all three other induction agents with respect to cardiovascular stability during induction and intubation.     

Midazolam as Adjunct to High-Dose Fentanyl Anaesthesia for Coronary Artery Bypass Grafting Operation

The usefulness of midazolam as an adjunct during high-dose fentanyl anaesthesia was studied by following the changes in the haemodynamics and total body oxygenation after an intravenous injection of 0.075 mg/kg and 0.15 mg/kg of midazolam during the induction of fentanyl (75 micrograms/kg)-oxygen anaesthesia for a coronary artery bypass operation. These responses were then compared to the changes seen in patients receiving the same fentanyl anaesthesia without the midazolam. A rapid decline after the midazolam injection was seen in the mean systemic arterial pressure (24-32%--the lowest individual value was 45 mmHg (6.0 kPa)) and in the systolic and diastolic pulmonary arterial pressures (29-33% and 30-31%) in 1-3 min. As measured 10 min after the midazolam injection, a decrease from the baseline was seen in the stroke index (25-30%), in the left ventricular stroke work index (46-42%) and in the right ventricular stroke work index (48-61%). These haemodynamic variables remained on a lower level throughout the study period (40 min) in the midazolam patients as compared to the controls. The tissue oxygenation seemed to be sufficient in all groups during the study period. An intravenous injection of a relatively low dose of midazolam during the induction of high-dose fentanyl anaesthesia seems to be followed by rapidly increased venous pooling and a moderately to severely decreased systemic arterial pressure. Based on the results of this study, midazolam cannot be recommended as an adjunct during high-dose fentanyl anaesthesia.     

Continuous propofol infusion versus enflurane in children operated on for strabismus. Comparison of the quality of anesthesia and recovery conditions

In children, the use of a continuous infusion of propofol has not yet been reported. A study was therefore designed to compare the characteristics of anaesthesia and recovery when either propofol or enflurance was used as the main anaesthetic agent. All 42 children (14 girls, 28 boys), ASA I and scheduled for corrective squint surgery under general anaesthesia, received 350 micrograms.kg-1 midazolam and 40 micrograms.kg-1 atropine intrarectally 20 min before induction, which was carried out with 3 mg.kg-1 propofol intravenously in 20 s. The patients were then randomly assigned to two groups, according to the drug used for maintenance: group P (n = 21) received a continuous intravenous infusion of propofol, 18 mg.kg-1.h-1 for the first 30 min and 15 mg.kg-1.h-1 thereafter; group E (n = 21) received 2.5%, then, after 30 min, 2% enflurane. Both groups were given 15 micrograms.kg-1 dextromoramide and 0.09 mg.kg-1 vecuronium. During anaesthesia, the following parameters were monitored: systolic (Pasys), diastolic (Padia) and mean arterial (Pa) pressures, heart rate (fc), the presence or not of an oculocardiac reflex with or without a 20% fall in fc which responded to 10-15 micrograms.kg-1 atropine, the appearance of a cardiac dysrhythmia, duration of anaesthesia and the delay before extubation. Recovery was assessed 1, 2, 4 and 6 h postoperatively by using both clinical and psychomotor criteria, the latter being adapted to children having one or both eyes occluded.(ABSTRACT TRUNCATED AT 250 WORDS)     

Propofol anaesthesia versus paracervical blockade with alfentanil and midazolam sedation for outpatient abortion

Propofol anaesthesia was compared with paracervical blockade in a prospective, randomized study of 59 abortion patients. All the patients received alfentanil 0.01 mg/kg i.v. at the start of anaesthesia and were randomized into two groups. Group R (regional, 31 patients): midazolam 0.1 mg/kg i.v. and paracervical blockade with 2 x 10 ml of mepivacaine 20 mg/ml + adrenaline 0.005 mg/ml. Group G (general, 28 patients): propofol 2.0 mg/kg i.v. induction and 75% nitrous oxide in oxygen spontaneous respiration. In 10 patients from the R-group venous blood samples were taken regularly for 30 min for serum concentration measurements (gas chromatography) of mepivacaine. Pain during induction of anaesthesia was remembered by 17% in Group G and 4% in Group R, whereas 8% in Group R remembered pain during the procedure compared with none in Group G. Of the patients in Group G, 25% had apnoea compared with none in Group R. In Group R the patients slept for 2.5 +/- 3.8 min (mean +/- s.d.) after induction compared with 12 +/- 4.0 min in Group G. Except for a better p-deletion score 30 min after the procedure in Group G, there was no difference in recovery function between the groups. Of the patients in Group G, 67% experienced postoperative pain compared with 23% in Group R. Maximum serum mepivacaine concentration (Group R) was reached at 15-30 min, range 1.5-5 micrograms/ml.     

Propofol in the surgery of the aortic bifurcation. Comparison with isoflurane

Two groups of nine patients each, all undergoing surgery for aorto-bifemoral prosthesis, were studied. They were premedicated with 10 mg morphine and 1 mg flunitrazepam. A Swan-Ganz catheter was then inserted. Cardiac output was measured by thermodilution. Haemodynamic parameters were measured before induction (t0), 15 min after intubation (t1), 10 min after the start of the surgical procedure (t2), 5 min before clamping the aorta (t3), whilst the aorta was clamped (t4), and a few minutes after unclamping. Group A received 2 mg X kg-1 propofol at induction, anaesthesia being maintained with 100 micrograms X kg-1 X min-1 propofol. Group B received 4 mg X kg-1 thiopentone, followed by isoflurane at the dose of 0.9 vol. %. Both groups received 5 micrograms X kg-1 fentanyl and 0.1 mg X kg-1 vecuronium to ease intubation. Artificial respiration was carried out with a mixture of 40% oxygen and 60% nitrous oxide. The fall in blood pressure between t2 and t3 was significantly more important in the propofol group (-16%). In the same group, the systolic blood pressure and heart rate fell by 23 and 19% respectively after induction (p less than 0.05); the cardiac index fell by 20% and the systemic vascular resistances did not change. The fall in blood pressure, heart rate and cardiac index were not significant for group B. The haemodynamic changes due to clamping of the aorta were not significant between or within groups. In group A, one patient presented with bradycardia, hypotension and myocardial ischaemia, and another died of postoperative ventricular fibrillation.(ABSTRACT TRUNCATED AT 250 WORDS)     

The influence of esmolol on the dose of propofol required for induction of anaesthesia

Cardiac output may be an important determinant of the induction dose of intravenous anaesthetic. Esmolol is known to reduce cardiac output, and we examined its effect on the propofol dose required for induction of anaesthesia. The size of the effect seen with esmolol was compared with midazolam co-induction. Sixty patients were randomly allocated to placebo (saline), esmolol (1mg x kg(-1) bolus, followed by an infusion at 250 microg x kg(-1)min(-1)) or midazolam (0.04 mg x kg(-1)) groups. Induction of anaesthesia commenced 3 min following the administration of the study drug, using a Diprifusor set to achieve plasma propofol concentrations of 10 microg x ml(-1) at 5 min. The primary end point used was the propofol dose per kg at loss of response to command. The mean (SD) propofol dose for each group was 2.38 (0.48) mg x kg(-1) for placebo, 1.79 (0.36) mg x kg(-1) for esmolol and 1.34 (0.35) mg x kg(-1) for midazolam (all means significantly different; p < 0.0005). We found that predosing with esmolol reduces the propofol requirements for induction of anaesthesia by 25%.     

Results of intravenous regional anaesthesia with distal forearm application

The aim of this study was to evaluate the clinical effectiveness of distal forearm intravenous regional anaesthesia (IVRA) with the tourniquet applied 3 cm above the wrist. One hundred and twenty patients undergoing out-patient hand surgery were operated for 13 different hand problems under distal forearm IVRA, using 10 ml of a solution containing 1.5 mg/kg prilocaine. Sensory block onset time was 4.5 minutes (3.5-6.5 min.). Mean tourniquet time was 17.6 minutes (range, 7-27.5 min). Mean tourniquet pressure was 240 mmHg (range, 220-270 mm Hg). The mean VAS score for tourniquet pain was 3.8 (range, 2-10). No local or systemic side effects related to the IVRA were observed. The study showed that distal forearm IVRA using 10 ml of a solution containing 1.5 mg/kg prilocaine provides safe, rapid and effective anaesthesia for patients undergoing outpatient hand surgery.     

Propofol combined with nitrous oxide-oxygen for induction and maintenance of anaesthesia

After a bolus of 2 mg/kg, propofol was given by continuous infusion (150 micrograms/kg/minute for 30 minutes and then 100 micrograms/kg/minute) supplemented with nitrous oxide for anaesthesia during ear surgery in 12 patients. Cardiovascular changes were not significant except for a decrease in heart rate after 60 minutes. Acid-base balance was unaffected by the amount of fatty emulsion. Cortisol levels showed a nonsignificant decrease during the prolonged administration of propofol but had recovered completely by one hour following anaesthesia. Mean blood concentrations of propofol were 10.5 micrograms/ml (SEM 1.2) at the onset of unconsciousness, between 3.4 and 4.5 micrograms/ml during continuous infusion and 2.9 micrograms/ml (SEM 0.3) on awakening. Patients opened their eyes 6 minutes (SEM 1) after discontinuation of the infusion, and were responsive at 7.5 minutes (SEM 0.5), which suggests that propofol infusion can be used safely for surgery of 2 hours' duration.     

Correlation and linear regression between blood pressure decreases after a test dose injection of propofol and that following anaesthesia induction

Propofol reduces systemic vascular resistance and suppresses cardiac function when injected rapidly. In this study we investigated whether blood pressure decrease after a minimal dose (test-dose) injection of propofol correlates with that after an induction-dose injection. Patients were randomly divided into two groups; anaesthesia was induced in group A (n = 60) using 1.5 mg/kg propofol and in group B (n = 61) using 2.0 mg/kg. Blood pressure reduction after a minimal dose injection (0.4 mg/kg) was examined non-invasively prior to anaesthetic induction. Bispectral Index monitoring was measured and sedation level scored to evaluate anaesthetic depth. After the minimal dose injection, 18 of 121 patients showed behaviour suggesting minor disinhibition, five patients were sedated and seven were drowsy. Oxygen saturation was not significantly changed after test-dose injection. Reduction in systolic blood pressure (mean +/- SD) was 17 +/- 11 mmHg after the minimal dose injection, 42 +/- 20 mmHg after a 1.5 mg/kg induction dose injection, and 42 +/- 22 mmHg after a 2.0 mg/kg induction-dose injection. In both groups, blood pressure after induction was significantly lower than the control value (P < 0.05). In both groups, a positive correlation was observed between blood pressure reduction after the minimal dose injection and that after the induction-dose injection [P < 0.01, R value for systolic blood pressure correlation in group A 0.712 (P < 0.01) and in group B 0.758 (P < 0.01)]. We concluded there was a positive correlation between blood pressure reduction after a minimal (test-dose) injection and that after an induction-dose injection.     

Ambulatory anesthesia and induced abortion. Comparative study of propofol-alfentanyl and ketamine-midazolam combinations

The use of propofol alone or with alfentanil in the day-case anaesthesia for abortion was compared with that of ketamine with midazolam. Two hundred young women were assigned to two successive series of two groups each. The four groups were: group 1 (2 mg . kg-1 propofol only); group II (0.5 mg . kg-1 ketamine with 0.25 mg . kg-1 midazolam); group III (2 mg . kg-1 propofol with 4 micrograms . kg-1 alfentanil); group IV (1 mg . kg-1 ketamine with 0.1 mg . kg-1 midazolam). All the patients were premedicated one hour before anaesthesia with 0.25 mg . kg-1 midazolam orally. All the patients were asleep at the end of the propofol injection (60 s), and 10 to 15 s later for the ketamine-midazolam groups. The haemodynamic parameters did not vary much during induction with ketamine-midazolam. In the propofol groups, the heart rate remained steady, with an 8 to 12% fall in blood pressure. A fall of the mandible was seen in 40 and 84% of the patients in the propofol groups, with a short apnoea in 32 and 48% of these same patients. Clinical recovery was very quick, less than 12 min for all groups. The four psychomotor and sensory tests were carried out at the 30th min by 95% of the patients in the propofol groups, whereas only 50% of those in the ketamine-midazolam groups did so. Speed and quality were significantly better in the propofol groups. The most frequent adverse effect of propofol was pain during injection in 32 and 14% of patients.(ABSTRACT TRUNCATED AT 250 WORDS)