Comparison of midazolam and propofol in combination with alfentanil for total intravenous anesthesia

Hemodynamic function during induction of anesthesia, the alfentanil and naloxone requirements, and the speed of recovery from total intravenous anesthesia with alfentanil/midazolam (group M, n = 10) or alfentanil/propofol (group P, n = 10) were compared in patients undergoing lower limb surgery. Twenty patients were randomly assigned to receive either 2 mg/kg propofol in 5 min followed by 9 mg.kg-1.h-1 for 30 min and 4.5 mg.kg-1.h-1 until skin closure, or 0.42 mg/kg midazolam in 5 min followed by 0.125 mg.kg-1.h-1 until skin closure. Simultaneously, a variable-rate infusion of alfentanil was given. Patients were ventilated with 30% oxygen in air. In both groups blood pressure and heart rate decreased significantly (P less than 0.02) and to a similar extent during induction. The total dose of alfentanil was similar in both groups. No patient in group P and nine patients in group M needed naloxone (average dose 130 +/- 70 micrograms, P less than 0.001). Recovery, as judged by psychomotor tests (90% score was reached at 1 h in the P group and at about 4 h in the M group, P less than 0.001), sedative scores, and orientation in time and place, was shorter in group P than in group M. The conclusion is reached that propofol is superior to midazolam in total intravenous anesthesia with alfentanil.     

Anaesthesia for computerised tomography of the brain in children: a comparison of propofol and thiopentone

Propofol (2,6-di-isopropylphenol) 1.5-2.0 mg/kg i.v. was compared with thiopentone 3.0-4.0 mg/kg i.v. as an induction agent in anaesthesia for computerised tomography (CT) of the brain in children. Both induction agents were combined with diazepam 0.2 mg/kg i.v. Thirty children (ASA physical status I-II) aged 3 to 10 years and scheduled for elective examination were included in the randomized study. The haemodynamic response to propofol and thiopentone did not differ between the groups. Spontaneous respiration was retained in all patients and no ventilatory support was required during anaesthesia. The incidence of side-effects did not differ between the groups. Pain on injection with propofol was rare (n = 1) after mixing 1 ml lignocaine (1%) with propofol prior to induction. The recovery times were significantly shorter in the propofol than in the thiopentone group. Propofol appears to be a promising alternative for use in short day-case anaesthesia for CT scanning in children.     

Propofol requirements for induction of anesthesia in children of different age groups.

To demonstrate any age-related differences in propofol requirements for induction of anesthesia, 150 healthy children aged 3-5 yr (n = 50), 6-9 yr (n = 50), and 10-15 yr (n = 50) scheduled for outpatient surgery were randomly assigned to receive an induction dose of propofol of 1.5, 2.0, 2.5, 3.0, or 3.5 mg/kg. To limit pain during injection, alfentanil (5 micrograms/kg) was administered before the propofol. Patients were classified as asleep or not asleep 30 s after the propofol. Incidence of excitation, injection pain, and apnea during induction of anesthesia were noted; arterial blood pressure and heart rate were recorded for 5 min after induction. More than 95% of the children were asleep in the dose groups receiving > or = 2.5 mg/kg. The number of patients falling asleep after receiving 1.5 mg/kg of propofol increased significantly with increasing age (P < 0.05); the difference between the oldest and the youngest age groups was the most significant (P < 0.05). Significant decreases in mean arterial blood pressure and heart rate occurred after induction in all dose and age groups without any systematic intergroup differences. Apnea occurred more frequently in older children (P < 0.01) and with larger doses (P < 0.01). The most frequent side effect was erythema near the site of injection, and its occurrence was dose dependent. The authors conclude that 2.5 mg/kg of propofol, if preceded by 5 micrograms/kg of alfentanil, is an appropriate induction dose for children aged 3-15 yr and that the sleep response to 1.5 mg/kg is more in older children.     

Initial experiences with propofol (Disoprivan) for anesthesia induction in pediatric anesthesia

Propofol is a new intravenous anesthetic agent that provides smooth and rapid induction of anesthesia. A short elimination half-life guarantees rapid recovery. Since it has been reformulated as an emulsion in soya bean oil, anaphylactoid reactions are unlikely to occur. As compared to adults, there is very little experience with propofol in pediatric anesthesia. The aim of this study was to evaluate propofol as an induction agent in children with respect to cardiovascular and respiratory effects and to investigate the incidence of other side-effects. METHOD. In 25 ASA I children aged 3-12 years (6.4 +/- 2.7 SD) anesthesia was induced with a single dose of propofol, after standard premedication with atropine 0.01 mg/kg and Thalamonal 0.04 ml/kg. Anesthesia was maintained with halothane, nitrous oxide, and oxygen. Blood pressure (BP), heart rate (HR), and arterial oxygen saturation (SaO2) were measured before and each minute for 6 min after propofol administration. The incidence of side-effects during induction of anesthesia as well as during recovery and the postoperative period were recorded. RESULTS. Propofol 2.5 mg/kg produced rapid and smooth induction of anesthesia. Mean arterial pressure decreased after 1 min by 14.3% with a maximum of 16.8% after 3 min. HR was influenced differently by propofol; children with initially high HR had a decrease in HR, whereas in children with a low initial rate, HR increased transiently. After 1 min, no further changes occurred. Although no apnea was observed, respiration was shallow and depressed, as indicated by a decrease in SaO2. Two children complained of pain and 4 of discomfort at the site of the injection; 1 of these developed transient phlebitis.(ABSTRACT TRUNCATED AT 250 WORDS)     

Propofol anesthesia in spontaneously breathing children undergoing magnetic resonance imaging: comparison of two propofol emulsions

BACKGROUND: This study evaluated a propofol-based anesthesia regimen with spontaneous breathing in pediatric patients scheduled for magnetic resonance imaging (MRI). METHODS: In this prospective, randomized, double-blind study propofol formulated with long-chain triglycerides (LCT) and mixed medium-chain/long-chain triglycerides (MCT/LCT) were used. Ninety patients aged 2.4 months to 7.3 years were premedicated with intravenous midazolam. Lidocaine was injected prior to propofol to reduce injection pain. Anesthesia was induced and maintained by propofol. Glycopyrronium bromide was administered for saliva reduction. Hemodynamics, blood oxygen saturation and endtidal capnography were continuously monitored. All patients received additional oxygen. The aggregated propofol dose for induction and maintenance of anesthesia was analyzed for therapeutic equivalence. Incidence of injection pain, laboratory safety values, vital signs, and the adverse event profile were analyzed to compare tolerability and safety. RESULTS: Propofol anesthesia was safe and successful in all children. Both propofol formulations were equivalent regarding dose requirements (mean induction and maintenance doses for anesthesia 2.0-4.0 mg.kg(-1) and 6.0-8.8 mg.kg(-1).h(-1) respectively; aggregated doses 8-13.26 mg.kg(-1)). There were no differences in drug safety such as hemodynamics, spontaneous breathing, injection pain, and laboratory values. Duration of induction and of recovery from anesthesia were short and all examinations were completed with minimal interruption. CONCLUSIONS: Propofol-based short-term anesthesia was well suited for anesthesia during MRI procedures in the studied pediatric patients. There were no clinically relevant differences between the two propofol formulations.     

An admixture of 3 mg·kg−1 of propofol and 3 mg·kg−1 of thiopentone reduces pain on injection in pediatric anesthesia

PURPOSE: To evaluate the incidence of pain on injection in children during anesthetic induction with a 3:1.2 volume admixture of 1% propofol and 2.5% thiopentone (P/T) compared to a 10:1 volume admixture of 1% propofol and 2% lidocaine (P/L). METHODS: After Ethics Committee approval and informed written parental consent, 127 children, aged one to ten years were studied and randomized into two groups; Group P/L received an induction with 5 mg x kg(-1) of 1% propofol and 1 mg x kg(-1) of lidocaine, Group P/T with 3 mg x kg(-1) of 1% propofol and 3 mg x kg(-1) of 2.5% thiopentone in a standardized fashion. A single, blinded observer scored pain behaviour defined as a motor response of the arm, a verbal complaint of pain, cry and/or one of three standardized facial expressions of pain. RESULTS: The incidence of pain was 14% in the P/T group, compared to 35% in the P/L group (chi(2)(1) = 7.5, P = 0.006). Motor response was the most frequent pain response in the P/L group (68%). CONCLUSION: The P/T admixture is a practical and efficacious alternative to P/L for reducing pain on induction in children. Further work to evaluate the optimum proportions and possible adverse effects of this admixture should be done.     

Total intravenous anesthesia with etomidate, alfentanil and droperidol

Forty-six women admitted for gynecologic surgery, were given alfentanil 1 mg, droperidol 2.5 mg and etomidate 0.3 mg/kg body weight intravenously for induction. Anesthesia was maintained using etomidate infused at a rate of 0.1 mg/kg/min for 5 minutes and at 0.01 mg/kg/min afterwards. Analgesia was achieved with a bolus injection of alfentanil prior to surgery, supplemented with additional injections of alfentanil as needed. Controlled ventilation was done with a mixture of air/oxygen. Anesthesia was uneventful in all but two patients. Blood pressure and heart rate remained stable during the entire operative period. Recovery from anesthesia was smooth, although the combination with etomidate and droperidol appears to prolong the recovery time.     

Tracheal intubation without the use of muscle relaxants: a technique using propofol and varying doses of alfentanil.

We have noted that tracheal intubation can be accomplished in many patients after induction of anesthesia with propofol and alfentanil without the simultaneous use of muscle relaxants. This study was designed to evaluate airway and intubating conditions after administration of propofol and alfentanil in 75 ASA physical status I or II outpatients with Mallampati class I airways undergoing various surgical procedures. The patients were randomly assigned to one of five groups for induction of anesthesia. All patients received midazolam 1 mg IV before induction of anesthesia. Group I patients (n = 15) received d-tubocurarine 3 mg, thiamylal 4 mg/kg, and succinylcholine 1 mg/kg IV. Groups II-V patients (n = 15 each) received alfentanil 30, 40, 50, or 60 micrograms/kg followed by propofol 2 mg/kg IV. No muscle relaxants were given to patients in groups II-V. Airway management was performed by one of the authors who was blinded as to the dose of alfentanil administered. After loss of consciousness, patients' lungs were ventilated via face mask, and the ease of ventilation was recorded. Jaw mobility was also assessed. Ninety seconds after administration of the propofol or thiamylal, laryngoscopy was performed and exposure of the glottis and position of the vocal cords were noted. Intubation of the trachea was performed and patient response was noted. Heart rate and arterial blood pressure were also recorded before induction of anesthesia, after induction, and then again after intubation of the trachea. The lungs of all patients were easily ventilated via mask, and the jaw was judged to be relaxed in all patients.(ABSTRACT TRUNCATED AT 250 WORDS)     

Comparative study between thiopental and propofol in short-duration anesthesia

In a randomized study, 80 healthy unpremedicated female patients were included. For short gynaecological procedures (curettage) they were anaesthetized with either propofol 2 mg/kg (n = 40) or thiopentone 5 mg/kg (n = 40) in combination with nitrous oxide/oxygen (1/1). Supplementary doses of propofol (25 mg) or thiopentone (50 mg) were given when necessary during the procedure. Propofol caused a significant fall in arterial blood pressure (greater than thiopentone in diastolic pressure) and a decrease in heart rate (thiopentone did not change heart rate). Discomfort on injection was similar in both groups. Recovery times were shorter in propofol group: Patients opened their eyes at 1.3 minutes, were awake at 2.2 minutes and could seat with no help at 5.2 minutes. In the thiopentone group, there was a greater incidence of nausea. Propofol was associated with euphoria, "clear-headedness" and pleasant dreams more than thiopentone. We conclude that propofol is a good alternative to thiopentone in short operative procedures.     

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

STUDY OBJECTIVE: To compare hemodynamics, recovery profiles, early postoperative pain control and costs of total intravenous anesthesia (TIVA) with propofol and remifentanil and propofol and alfentanil. DESIGN: Randomized, double-blind study. SETTING: University hospital. PATIENTS: 40 ASA physical status I and II adult patients scheduled for lumbar discectomy. INTERVENTIONS: Patients were randomly assigned to receive either remifentanil-propofol or alfentanil-propofol. Anesthesia was induced with remifentanil 1 microg kg(-1) or alfentanil 20 microg kg(-1) with propofol 2 mg kg(-1), and maintained with infusions of propofol 150 to 100 microg kg(-1)min(-1) and either remifentanil 0.1 microg kg(-1) min(-1) or alfentanil 0.5 microg kg(-1) min(-1). MEASUREMENTS: Hemodynamic parameters (heart rate and mean arterial pressure), times to awakening, and tracheal extubation were recorded. In the postanesthesia care unit, pain level, frequency of analgesic demand, frequency of postoperative nausea and vomiting (PONV), partial oxygen saturation (SpO2), and respiratory rates were noted. Drug dosages and costs of each technique were determined. MAIN RESULTS: The mean arterial pressure significantly decreased compared to baseline values 1 minute after induction (p < 0.05) in both groups, and it significantly decreased at 5, 15, and 30 minutes perioperatively in the remifentanil group compared to the alfentanil group (p < 0.05). Time of extubation, spontaneous eye opening, and response to verbal command were similar in both groups. Visual analog scale pain scores at 30 minutes and 60 minutes were significantly lower in the alfentanil group than remifentanil group (p < 0.05). At 15, 30, and 60 minutes after terminating the operation oxygen saturation and respiratory rate were significantly higher (p < 0.05) and analgesics were required sooner in the remifentanil group than the alfentanil group (p < 0.05). The frequency of PONV was similar in both groups. The remifentanil-propofol anesthesia was found to be slightly more expensive as compared to the alfentanil based TIVA (33.41 +/- 4.53 vs. 29.97 +/- 4.1 USD) (p < 0.05). CONCLUSIONS: Both remifentanil and alfentanil provided a reasonably rapid and reliable recovery. The remifentanil-based TIVA was associated with high intraoperative cost and early postoperative pain, but it allowed a more rapid respiratory recovery.     

Preinduction atropine or glycopyrrolate and hemodynamic changes associated with induction and maintenance of anesthesia with propofol and alfentanil

Total intravenous anesthesia by infusions of propofol and alfentanil may be associated with decreases in heart rate and blood pressure. The effects of two vagolytic agents on these hemodynamic changes were studied in 24 ASA physical status 1 patients undergoing body surface surgery. Patients were randomly allocated to receive atropine 10 micrograms/kg, glycopyrrolate, 5 micrograms/kg, or 0.9% sodium chloride, intravenously, 5 min before induction of anesthesia with loading doses of alfentanil, 50 micrograms/kg and propofol 1 mg/kg. Anesthesia was maintained with infusions of alfentanil 50 micrograms.kg-1.hr-1, and propofol 10 mg.kg-1.hr-1 for the first 10 min, 8 mg.kg-1.hr-1 for the next 10 min, and 6 mg.kg-1.hr-1 thereafter. Patients given glycopyrrolate before anesthesia had significantly higher arterial pressures than did patients receiving either atropine or saline, even though heart rates increased equally after glycopyrrolate and atropine.     

Vomiting and Recovery after Outpatient Tonsillectomy and Adenoidectomy in Children: Comparison of Four Anesthetic Techniques Using Nitrous Oxide with Halothane or Propofol

Background: The authors' purpose in this study was to compare prospectively four different anesthetic induction and maintenance techniques using nitrous oxide with halothane and/or propofol for vomiting and recovery after outpatient tonsillectomy and adenoidectomy procedures in children.

Methods: Eighty unpremedicated children, aged 3-10 yr, were assigned randomly to four groups: group H/H, 0.5-2% halothane induction/halothane maintenance; group P/P, 3-5 mg *symbol* kg sup -1 propofol induction and 0.1-0.3 mg *symbol* kg sup -1 *symbol* min sup -1 propofol maintenance; group H/P, 0.1-0.3 mg *symbol* kg sup -1 *symbol* min sup -1 halothane induction/propofol maintenance; and group P/H, 3-5 mg *symbol* kg sup -1 propofol induction and 0.5-2% halothane maintenance. Nitrous oxide (67%) and oxygen (33%) were administered in all the groups. Other treatments and procedures were standardized intra- and postoperatively. Results of postoperative vomiting and recovery were analyzed in the first 6 h and beyond 6 h.

Results: Logistic regression showed that vomiting occurred 3.5 times as often when halothane was used for maintenance of anesthesia (groups H/H and P/H) compared with the use of propofol (groups P/P and H/P; Odds Ratio 3.5; 95% confidence interval 1.3 and 9.4, respectively; P = 0.012). A significant association between vomiting (< 6 h: yes/no) and discharge times (> 6 h: yes/no) (Odd's Ratio = 3.6; 95% confidence interval: 1.02, 12.4, respectively) (P = 0.046) was shown. However, no significant differences among the groups in the incidence of vomiting beyond 6 h, recurrent vomiting, or hospital discharge times were shown.     

Sevoflurane-maintained anesthesia induced with propofol or sevoflurane in small children: induction and recovery characteristics

PURPOSE: To compare the induction and recovery characteristics of sevoflurane anesthesia induced with either propofol or sevoflurane in pediatric outpatients. METHODS: Fifty-two children, aged 1-3 yr, presenting for ambulatory adenoidectomy were randomly allocated to receive 3 mg.kg-1 propofol i.v. or sevoflurane 8% inspired concentration for induction of anesthesia. Tracheal intubation was facilitated with 0.2 mg.kg-1 mivacurium. Anesthesia was maintained with nitrous oxide/oxygen (FiO2 0.3) and sevoflurane approximately 3-5% inspired concentration with controlled ventilation. Intubation was assessed by an anesthetist blinded to the induction method. Recovery characteristics were compared using the modified Aldrete scoring system, the Pain/Discomfort scale and measuring specific recovery times. A postoperative questionnaire was used to evaluate the children's well-being at home. RESULTS: Intubating conditions were similar in both groups. Emergence from anesthesia occurred earlier with sevoflurane for induction than with propofol (11 +/- 4 vs 17 +/- 7 min (mean +/- SD), P = 0.0002). More children in the sevoflurane group achieved full points on the modified Aldrete scoring system during the first 20 min after anesthesia (P < 0.05). However, children in the sevoflurane group scored higher in the Pain/Discomfort scale at 10 min after anesthesia (P = 0.04) and were given postoperative analgesics earlier than children in the propofol group (13 +/- 5 min vs 18 +/- 11 min, P = 0.03). The time to meet discharge criteria and recovery at home were similar. CONCLUSIONS: Induction of sevoflurane anesthesia with propofol for day-case adenoidectomy results in longer, but more calm, early recovery but does not delay discharge or affect recovery at home.     

Midazolam premedication delays recovery from propofol-induced sevoflurane anesthesia in children 1–3 yr

PURPOSE: To study the effect of midazolam premedication on the recovery characteristics of sevoflurane anesthesia induced with propofol in pediatric outpatients. METHODS: Sixty children, one to three years, presenting for ambulatory adenoidectomy were randomly assigned , in a double-blind fashion, to receive either 0.5 mg x kg(-1) midazolam (Group M) or placebo (Group P) p.o. 30 min before anesthesia. Anesthesia was induced with 10 microg x kg(-1) atropine, 10 microg x kg(-1) alfentanil, and 3-4 mg x kg(-1) propofol i.v.. Tracheal intubation was facilitated with 0.2 mg x kg(-1) mivacurium. Anesthesia was maintained with nitrous oxide/oxygen (FiO2 0.3) and sevoflurane with controlled ventilation. Recovery characteristics were compared using the modified Aldrete scoring system, the Pain/Discomfort scale and measuring specific recovery end-points (emergence, full Aldrete score, discharge). A postoperative questionnaire was used to evaluate the children's well-being at home until 24 hr after discharge. RESULTS: Emergence from anesthesia (22 +/- 9 vs 16 +/- 6 min (mean +/- SD), P = 0.005) and achieving full Aldrete scores (30 +/- 11 vs 24 +/- 16 min, P = 0.006) were delayed in patients receiving midazolam. Children in the placebo group were given postoperative analgesia sooner than those in the midazolam group (18 +/- 11 vs 23 +/- 8 min, P = 0.009). More children premedicated with midazolam suffered from arousal distress (20% vs 3%, P = 0.04) and scored higher on the Pain/Discomfort scale (P = 0.004) at 20 min after arrival in the recovery room. Discharge was not affected by premedication and well-being at home was similar in the groups. CONCLUSIONS: Oral premedication with midazolam delays early recovery but not discharge after ambulatory sevoflurane anesthesia induced with propofol in children one to three years. Midazolam did not improve the quality of recovery.     

Assessment of depth of anesthesia and postoperative respiratory recovery after remifentanil- versus alfentanil-based total intravenous anesthesia in patients undergoing ear-nose-throat surgery

BACKGROUND: The authors investigated whether total intravenous anesthesia (TIVA) with precalculated equipotent infusion schemes for remifentanil and alfentanil would ensure appropriate analgesia and that remifentanil would result in better recovery characteristics. METHODS: Forty consenting patients (classified as American Society of Anesthesiologists physical status I-III) scheduled for microlaryngoscopy were randomized to receive, in a double-blind manner, either remifentanil (loading dose 1 microg/kg; maintenance infusion, 0.25 microg x kg(-1) x min-1) or alfentanil (loading dose, 50 microg/kg; maintenance infusion, 1 microg x kg(-1) x min-1) as the analgesic component of TIVA. They were combined with propofol (loading dose, 2 mg/kg; maintenance infusion, 100 microg x kg(-1) min(-1)). To insure an equal state of anesthesia, the opioids were titrated to maintain heart rate and mean arterial pressure within 20% of baseline, and propofol was titrated to keep the bispectral index (BIS) less than 60. Neuromuscular blockade was achieved with succinylcholine. Drug dosages and the times from cessation of anesthesia to extubation, verbal response, recovery of ventilation, and neuropsychological testing, orientation, and discharge readiness were recorded. RESULTS: Demographics, duration of surgery, and anesthesia were similar between the two groups. Both groups received similar propofol doses. There were no difference in BIS values preoperatively (mean, 96), intraoperatively (mean, 55), and postoperatively (mean, 96). Recovery of BIS and times for verbal response did not differ. At 20, 30, and 40 min after terminating the opioid infusion, the peripheral oxygen saturation and respiratory rate were significantly higher in the remifentanil group compared with the alfentanil group. CONCLUSIONS: When both the hypnotic and analgesic components of a TIVA-based anesthetic are administered in equipotent doses, remifentanil provides a more rapid respiratory recovery, even after brief surgical procedures, compared with alfentanil.     

The comparative effect of single dose mivacurium during sevoflurane or propofol anesthesia in children

BACKGROUND: We aimed to randomly compare intubating conditions, recovery characteristics and neuromuscular effects of single dose of mivacurium (0.2 mg.kg(-1)) during sevoflurane vs. propofol anesthesia in 60 healthy children, undergoing inguinal surgery. METHODS: All children were randomly allocated to receive 2 mg.kg(-1) propofol iv or sevoflurane 8% inspired concentration for induction of anesthesia. Anaesthesia was maintained with 66% nitrous oxide in oxygen and 100-120 microg.kg(-1) propofol or sevoflurane approximately 2-3% inspired concentration with controlled ventilation. The ulnar nerve was stimulated at the wrist by a train-of four (TOF) stimulus every 20 s and neuromuscular function was measured at the adductor pollicis. When the response to TOF was stable, 0.2 mg.kg(-1) mivacurium was given. The trachea was intubated successfully at the first attempt in all patients. RESULTS: Onset time following a single dose of mivacurium was shorter in the sevoflurane group (2.99 min), than in the propofol group (4.42 min). The times to 25, 50, 75, and 90% recovery were significantly longer in the sevoflurane group (13.1, 15.7, 18.6, and 21.2 min, respectively) than in the propofol group (11.4, 13.2, 14.4, and 17.2 min respectively). TOF ratios of 50, 70, and 90% were significantly occurred later in sevoflurane group than propofol group. CONCLUSIONS: Our results indicate that when compared with propofol group, the sevoflurane group had an accelerated onset and a delayed recovery of neuromuscular block induced by mivacurium in children.     

Pain during injection of propofol: the effect of prior administration of ephedrine

Propofol causes pain on intravenous injection in 28 to 90% of patients. A number of techniques have been tried to minimize propofol-induced pain, with variable results. In a randomized, double-blind, placebo-controlled trial, we compared the efficacy of ephedrine 30 microg/kg pretreatment to lignocaine 40 mg for prevention of propofol-induced pain. Ninety-three adult patients, ASA 1 and 2, undergoing elective laparoscopic cholecystectomy were randomly assigned to three groups of 31 each. Group 1 received normal saline, group 2 received lignocaine 2% (40 mg) and group 3 received 30 microg/kg ephedrine. All pretreatment drugs were made up to 2 ml. Pain at the time of propofol injection was assessed on a four-point scale: 0=no pain, 1 =mild pain, 2=moderate pain, and 3=severe pain. Twenty-seven patients (87%) of ephedrine pretreatment patients had pain during intravenous injection of propofol as compared to 24 (77%) in the normal saline group. In the lignocaine group, propofol-induced pain was observed in only 13 (42%) when compared with other study groups (P<0.05). Pretreatment with ephedrine 30 microg/kg did not attenuate pain associated with intravenous injection of propofol, nor did it improve haemodynamic stability during induction. However, pretreatment with 2% lignocaine (40 mg) was effective in attenuating propofol-associated pain.     

Alfentanil used to supplement propofol infusions for oesophagoscopy and bronchoscopy

This randomised double-blinded study compared the cardiovascular stability and rate of recovery when propofol infusions with or without alfentanil were used to provide anaesthesia for rigid oesophagoscopy and (or) bronchoscopy. Forty-six patients were allocated randomly to receive either alfentanil 10 micrograms/kg or saline just before a rapid sequence induction with propofol. Suxamethonium 1 mg/kg was given and infusions of suxamethonium 10 mg/minute and propofol (10 mg/kg/hour for 10 minutes, 8 mg/kg/hour for 10 minutes and then 6 mg/kg/hour thereafter) were started. There were 23 patients in each group with no significant demographic differences between the groups. A significantly mean lower induction dose of propofol was needed in the alfentanil group (1.7 mg/kg compared to 2.2 mg/kg). Cardiovascular measurements were made on the ward pre-operatively, just before induction, just after induction, just after intubation, and at 3-minute intervals thereafter. Arterial pressure was significantly lower during the procedure in the patients who received alfentanil and there was a significant incidence of hypotension. There was no significant difference between the groups in respect of heart rate, with a significant increase in both groups just after intubation compared to the baseline values. Recovery from anaesthesia was assessed using the critical flicker fusion threshold. No differences were found between the groups and patients in both groups had returned to baseline values by 60 minutes. No patient had any recall of intra-operative events, and there were no other adverse effects of any significance.     

Total intravenous anesthesia using propofol and alfentanil as compared to combined inhalation anesthesia reduces the flow velocity in the middle cerebral artery. A Doppler sonographic study]

Anesthesia for craniotomies should guarantee hemodynamic stability, preservation of cerebral autoregulation, and rapid postoperative recovery of consciousness. Increases in intracranial pressure (ICP) and postoperative respiratory depression should be avoided. Combined anesthesia (KA) with N2O and volatile anesthetics may increase cerebral blood flow (CBF), ICP, and cerebral oxygen consumption. According to recent studies, total intravenous anesthesia (TIVA) with propofol and alfentanil seems to best fulfill the requirements. Using transcranial Doppler sonography (TCD) (TC2-64, EME), we studied the influence of TIVA and KA under normo- and hyperventilation on the blood flow velocity (BFV) and pulsatility of the middle cerebral artery (MCA). METHODS. Two groups of 10 patients each undergoing craniotomy were investigated. Systolic and mean BFV, pulsatility index, mean arterial blood pressure, heart rate, and arterial CO2 tension were measured at four time intervals: (1) preoperatively; (2) 15 min after anesthesia induction under normoventilation, preoperatively; (3) 25 min after anesthesia induction under hyperventilation, preoperatively; and (4) 6 h postoperatively. The patients were premedicated with flunitrazepam 1 mg PO. TIVA was induced with 60 mg propofol, 1 mg alfentanil, and 6 mg vecuronium; simultaneously infusions of propofol (15 mg/min) and alfentanil (0.3 mg/min) were started and were maintained until the dura was completely opened. The infusion rates were then reduced to 6 mg/min propofol until skin suturing and 0.1 mg/min alfentanil until dural suturing was completed. Patients were ventilated with O2/air (fiO2 = 0.5). In the KA group anesthesia was induced with 4-6 mg/kg thiopental, 0.15 mg fentanyl, and 6 mg vecuronium and maintained with boluses of fentanyl, N2O (fiO2 = 0.5), and isoflurane (1.3 MAC). The time course is illustrated in Figs. 1 and 2 and the results are shown in Tables 1 and 2. They were tested using a one-factor analysis of variance and the Kruskal-Wallis range test. RESULTS. There was a significant decrease in systolic and mean BFV combined with an increase in pulsatility index after induction of TIVA, while KA induction effected no significant change in cerebral hemodynamics. The subsequent hyperventilation caused a similar decrease in mean BFV and increase in pulsatility index in both groups. CONCLUSION. Using the assumption that the diameter of the MCA is nearly constant, the reduction in BFV associated with an increase in pulsatility during TIVA is explainable as a decrease in CBF. By having a comparable influence on hemodynamics, the reduction in CBF with increase in cerebral vascular resistance seems to make TIVA the more advantageous anesthesia technique for patients with reduced intracranial compliance.     

Comparison of propofol and thiopental/halothane for short-duration ENT surgical procedures in children

Experiences with propofol in pediatric anesthesia are limited. We undertook a study to evaluate the quality of induction and recovery from anesthesia with propofol compared to thiopental/halothane. Twenty children received 3 mg.kg-1.min-1 of propofol as a loading dose followed by a maintenance dose of 0.1 mg.kg-1.min-1 (+/- 10%). Twenty children received 5-7 mg/kg of thiopental, and maintenance was provided with halothane (0.5%-1.5%). The interval between the end of the administration of propofol or thiopental/halothane and extubation, as well to discharge to the ward, was significantly shorter with propofol (4.4 versus 13.5 min and 7.22 versus 30.4 min, respectively). Spontaneous movements and pain on injection were seen significantly more frequently with propofol, whereas laryngospasm and hiccup were only observed with thiopental. During the first 6 h after the surgical procedure, analgesics were needed significantly more often in the thiopental group. Nausea and vomiting also were observed more frequently in the thiopental group. In conclusion, propofol used as a single anesthetic is a satisfactory technique for ENT surgery of short duration in children.