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 for induction and maintenance of anaesthesia at Caesarean section A comparison with thiopentone/enflurane

A propofol infusion regimen and a standard general anaesthetic were compared in 40 Chinese women undergoing elective Caesarean section. Twenty patients received propofol 2 mg/kg for induction of anaesthesia followed by propofol 6 mg/kg/hour, while 20 patients received thiopentone 4 mg/kg with enflurane 1% for maintenance of anaesthesia. All patients were given atracurium and their lungs ventilated with nitrous oxide 50% in oxygen until delivery of the neonate. The hypertensive response after intubation was of shorter duration in the propofol group compared with the thiopentone group. Induction to delivery times ranged from 5 to 14 minutes and neonates from both groups had similar and satisfactory Apgar scores. Neurologic and Adaptive Capacity Scores and umbilical cord blood gas analysis. However, a prolonged propofol infusion time before delivery may cause lower Neurologic and Adaptive Capacity Scores. There were no differences in maternal recovery times or psychomotor performance.     

Anaesthesia for cardioversion: A comparison of propofol and thiopentone

Propofol (2,6-diisopropylphenol) 2.5 mg.kg-1 IV was compared with thiopentone 5 mg.kg-1 IV as an induction agent in anaesthesia for elective cardioversion. Thirty-five patients (ASA physical status II-III) with atrial fibrillation were included. Thirty patients were randomized to receive propofol or thiopentone. Five patients were treated twice during the study period and anaesthetized with both agents (the first treatment according to the random order and the second with the agent not used on the first occasion). The induction characteristics and the haemodynamic response for propofol and thiopentone were similar. The success rate of cardioversion did not differ between the groups. Recovery times were shorter after propofol than after thiopentone with respect to ocular muscle balance, central integration and subjective sedation of patients. The incidence of side-effects did not differ between the groups. None of the patients reported any awareness during the procedure. All five patients treated twice (with both agents) assessed the anaesthetic procedure with propofol as being more pleasant than that with thiopentone.     

Propofol vs thiopentone as anaesthetic agents for short operative procedures

In a randomized open study, 120 healthy female patients were included. For short gynaecological procedures they were anaesthetized with either propofol 2.5 mg X kg-1 (n = 60) or thiopentone 5 mg X kg-1 (n = 60) in combination with nitrous oxide/oxygen (67%/33%). Supplementary doses of propofol (10-20 mg) or thiopentone (25-50 mg) were given when necessary during the procedure. Induction characteristics for propofol and thiopentone 1 min after start of induction were similar. Propofol seemed to have a more depressant effect than thiopentone on the circulatory response to anaesthesia. Recovery times from the end of the operative procedure until the patients opened their eyes on command and were orientated were shorter in the propofol patients compared to the thiopentone patients. In the propofol group, patients recalled discomfort on injection more often than patients anaesthetized with thiopentone. Otherwise, the side-effects were similar in both groups. We conclude that propofol is similar to thiopentone in its anaesthetic qualities during induction and maintenance of short anaesthetic procedures. Propofol was associated with a more rapid emergence from anaesthesia than thiopentone.     

Comparison of propofol and thiopentone for laryngeal mask insertion

Conditions for insertion of the laryngeal mask were assessed following induction of anaesthesia with either propofol 2.5 mg/kg or thiopentone 4.0 mg/kg in 80 patients premedicated with diazepam 10 mg. Insertion following induction with thiopentone resulted in a greater incidence of gagging (p less than 0.01). The use of additional induction agent, where necessary, resulted in no ultimate significant difference between the groups for the provision of satisfactory conditions.     

Comparison of induction characteristics of four intravenous anaesthetic agents

The induction characteristics of thiopentone, etomidate and methohexitone have been compared to those of propofol (2,6 di-isopropyl phenol) in unpremedicated patients. Propofol 2.5 mg/kg caused significantly more hypotension, excitatory side effects and pain on injection at the dorsum of hand than thiopentone 5 mg/kg. However, with regard to the latter two sequelae, etomidate 0.3 mg/kg and methohexitone 1.5 mg/kg caused similar or more frequent upset. Propofol 2.0 mg/kg was equipotent with thiopentone 4.0 mg/kg in terms of successful induction of anaesthesia. Hypotension may contraindicate the use of propofol in the hypovolaemic or unfit patient.     

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.     

Induction characteristics of propofol in children: comparison with thiopentone

The induction characteristics of propofol were studied and compared with thiopentone in children aged 3-14 years who received either no premedication or pethidine-atropine or trimeprazine. Anaesthesia was maintained with nitrous oxide in oxygen, and isoflurane. The induction doses of propofol and thiopentone were 2.9 mg/kg and 6.5-7.1 mg/kg respectively; premedication had no significant effect on the induction doses of either agent. Spontaneous movement and hypertonus occurred in about 20% of children with both agents. The use of propofol was associated with a high incidence of pain on injection (injections were mostly in veins on the dorsum of the hand), but this was reduced by mixing lignocaine with propofol. Cardiovascular effects were not clinically significant with either agent. Apnoea occurred in 35% of patients given propofol and in 50% of those given thiopentone. Children anaesthetised with propofol awoke significantly earlier after cessation of all anaesthesia. It is concluded that the use of propofol is safe in children and may have advantages where early recovery from anaesthesia is desirable, but offers no advantage over thiopentone for routine induction of anaesthesia.     

Tracheal intubation after induction of anaesthesia with thiopentone or propofol without muscle relaxants

This study was designed to compare the ease of performing laryngoscopy and endotracheal intubation without muscle relaxants after the induction of anaesthesia with either thiopentone or propofol in 106 patients scheduled for elective surgery. Thiopentone (5 mg/kg) or propofol (2.5 mg/kg), supplemented with lidocaine (1.5 mg/kg) and alfentanil (30 micrograms/kg), were used in random order for the induction of anaesthesia. Jaw tone, visualisation of the larynx, position of vocal cords, ease of intubation and tolerance of the tracheal tube were assessed. The jaw was relaxed and the vocal cords were immobile/open in most patients in both groups. Visualisation of the larynx was good in 60 and 46% and intubation was easy in 48 and 22% of the patients given thiopentone and propofol, respectively (P less than 0.05 between groups for intubation). After induction of anaesthesia with thiopentone or propofol, endotracheal intubation is not recommended without the use of muscle relaxants.     

Anaesthesia for laparoscopy

This is a report about five anaesthetic techniques for laparoscopy. Propofol and etomidate were used for total intravenous anaesthesia. Propofol, etomidate and thiopentone were used as induction agents prior to inhalational anaesthesia with isoflurane and nitrous oxide. Fentanyl was used for analgesia. Induction with propofol and thiopentone was rapid. Etomidate induction was characterised by myoclonus. Maintenance was smooth with inhalational anaesthesia. Of the groups that received total intravenous anaesthesia, propofol provided stable anaesthesia but required extra bolus doses. Recovery was the most rapid following total intravenous anaesthesia with propofol. Postoperative side effects were much lower after propofol. No difference was observed between the groups with regard to changes in arterial blood pressure and heart rate.     

Ventilatory effects of propofol during induction of anaesthesia

The ventilatory effects of induction of anaesthesia with either propofol 2.5 mg/kg or thiopentone 4.0 mg/kg have been observed in patients premedicated with either atropine alone or papaveretum and hyoscine. Induction of anaesthesia with propofol was accompanied by a greater degree of ventilatory depression which was of longer duration than following thiopentone. The effect was accentuated by the opioid premedication.     

Comparison of propofol and increased doses of thiopentone for laryngeal mask insertion

Conditions for insertion of the laryngeal mask were assessed following induction of anaesthesia with either propofol 2.5 mg/kg, thiopentone 5.0 mg/kg or thiopentone 6.0 mg/kg in 120 patients premedicated with diazepam 10 mg. Insertion following induction with thiopentone 5.0 mg/kg and 6.0 mg/kg resulted in a greater incidence of gagging ( P <0.001 and P <0.05, respectively) compared with propofol 2.5 mg/kg.     

The haemodynamic effects of intravenous induction

The haemodynamic changes following induction of anaesthesia with equipotent doses of propofol and thiopentone have been compared. Propofol caused a significant fall in arterial blood pressure and total peripheral resistance, with a slight fall in cardiac output. There were no changes in heart rate. Apart from an initial, but statistically insignificant increase in heart rate, similar changes were produced by thiopentone, but to a lesser degree. It is concluded that induction of anaesthesia with propofol results in acceptable haemodynamic changes, but that the agent is more depressant to the cardiovascular system than thiopentone.     

Propofol and thiopentone for caesarean section revisited: maternal effects and neonatal outcome

In 56 women undergoing elective caesarean section, general anaesthesia was induced with either propofol 1% or thiopentone 2.5% followed by 50% nitrous oxide in oxygen and isoflurane 0.75% until delivery. In the thiopentone group the arterial pressure rose following tracheal intubation and skin incision, while in the propofol group there was a significant tendency to hypotension immediately following induction of anaesthesia. There were differences in electroencephalogram (EEG) between the groups, while laryngoscopy, intubation and surgical stimulation had no effect on EEG pattern. Recovery after anaesthesia did not differ between groups. None of the patients had recall of the intraoperative period, but 53% of patients induced with propofol showed signs of light anaesthesia between induction and delivery. Neonates in the propofol group had lower Apgar scores 1 min after birth than those in the thiopentone group, but these differences were no longer significant at 5 min. No differences were noted in neurobehavioural status at 1, 4 and 24 h.     

Bispectral index during modified rapid sequence induction using thiopentone or propofol and rocuronium

This randomized controlled trial compared Bispectral Index (BIS) values in 40 patients after a modified rapid sequence induction using thiopentone 4 mg/kg or propofol 2 mg/kg with rocuronium 0.6 mg/kg as muscle relaxant. Endotracheal intubation was performed at 60 seconds from induction of anaesthesia and BIS values were recorded for three minutes after induction. At the 120, 150 and 180 second measurements there was a significantly greater proportion of subjects with BIS values < or = 60 ("anaesthetized") in the propofol group compared with the thiopentone group (P values < 0.02, < 0.01 and < 0.01 respectively). All intubations were completed within two minutes. No explicit recall of intubation was detected clinically with either induction agent. The BIS scores we have measured suggest that thiopentone 4 mg/kg is more likely to be associated with lighter planes of anaesthesia and consequent risk of awareness than propofol 2 mg/kg, if intubation is delayed or prolonged.     

Propofol influences the electroretinogram to a lesser degree than thiopentone

Background: The Electroretinogram (ERG) is used clinically to assess the function of retina. Anaesthetic agents are known to affect ERG, and as anaesthesia is often needed in children and uncooperative patients, knowledge about its effects is of clinical importance. Barbiturates selectively depress ERG components, and we compared thiopentone with propofol to assess if the latter preserved retinal function better.
Methods: Ten pigs, average weight 17 kg (SD ± 2 kg) were anaesthetized randomly with propofol 10 mg kg^-1 or thiopentone 30 mg kg^-1. Anaesthesia was maintained by 65% nitrous oxide in oxygen and continuous infusion of the induction agent, i.e. 10 mg kg^-1 h^-1 of propofol, or 10 mg kg^-1 h^-1 for the first hour, then 5 mg kg^-1 h^-1 of thiopentone, with doses being based on pilot studies. After an interval of one week the programme was repeated using the other agent. After 40 minutes dark-adaptation, responses to single flashes of graded intensities from a xenon flashlamp were recorded at five-minute intervals. The a- and b-wave amplitudes and implicit times (time to peak), and a-wave slopes were determined.
Results: The b-wave implicit time was significantly shorter during propofol anaesthesia than when using thiopentone. The effect was most pronounced at the lowest intensities (P < 0.01). No statistically significant differences were found in the amplitudes of the b-waves. The a-wave appeared at lower stimulus intensity (P < 0.05) and the a-wave slopes were significantly steeper (P < 0.01) during propofol anaesthesia.
Conclusion: Propofol accordingly appeared to preserve the photoreceptor response better than thiopentone, and may therefore be considered to be more suitable for ERG recordings than thiopentone.     

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.     

Propofol infusion anaesthesia for Caesarean section

Two propofol infusion regimens and a standard general anaesthetic were compared in thirty Chinese women undergoing elective Caesarean section. After induction of anaesthesia with propofol 2 mg.kg-1, ten patients received propofol 6 mg.kg-1.hr-1 and nitrous oxide 50 per cent in oxygen while ten were given propofol 9 mg.kg-1.hr-1 with 100 per cent oxygen. The other ten patients received thiopentone 4 mg.kg-1 and nitrous oxide 50 per cent in oxygen with enflurane one per cent. Maternal recovery times and psychomotor performance were recorded. Neonates were assessed by Apgar scores, neurologic and adapative capacity scores (NACS) and umbilical cord blood gas analysis. Haemodynamic changes were similar immediately following induction but the low propofol infusion group had the best haemodynamic stability subsequently. Recovery times were fastest in the low-infusion group but there were no differences in later postbox testing. Neonatal Apgar scores and umbilical blood gas analysis were similar but NACS at two hours were poorer in the high infusion group. A propofol infusion coupled with nitrous oxide appears to be a satisfactory technique for Caesarean section.     

Anaesthesia for short outpatient procedures. A comparison between thiopentone and propofol in combination with fentanyl or alfentanil

We studied supplementation of propofol or thiopentone anaesthesia with 0.5 or 1.0 mg alfentanil or 0.05 or 0.1 mg fentanyl for minor gynaecological outpatient procedures. Four hundred patients scheduled for elective termination of pregnancy were randomly allocated to one of eight groups. Induction agent doses, peroperative complications, complaints about pain and emesis during the postoperative period, and time to discharge were studied. Propofol compared to thiopentone was associated with a shorter time to discharge, 103±28 and 115±33 minutes respectively ( P <0.05) and anxiety during recovery was more frequent in the thiopentone group ( P <0.05). The need for postoperative reserve analgesics was less in the alfentanil group ( P <0.05). We found, however, no major differences between the supplementations tested regarding the total dose of induction agent, emesis or time to discharge. Supplementation with 1.0 mg of alfentanil to propofol was found to be the best combination tested for short outpatient procedures.     

Cardiovascular effects of a combination of vecuronium and low-dose fentanyl in atropinized and non-atropinized subjects]

The cardiovascular effects of the pharmacologic association of low-dose fentanyl (2 micrograms/kg) and vecuronium (120 micrograms/kg) have been studied in 38 ASA I and II atropinized and non-atropinized patients scheduled for abdominal surgery during induction of anaesthesia with thiopentone or propofol. Whatever the induction agent used, heart rate was consistently reduced in patients not receiving an anticholinergic drug, while it was unchanged in patients treated with atropine intravenously. In non-atropinized patients impressively lower minimum heart rates were observed during induction of anaesthesia with thiopentone. In this last group one patient suffered from a cardiac arrest resolved without sequelae. In patients treated with the association between vecuronium and low doses of fentanyl a pretreatment with atropine is always indicated. Propofol seems to be a better induction agent than thiopentone.