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PubMed2003

Subhypnotic doses of propofol accelerate extinction of conditioned taste aversion.

Subhypnotic doses of propofol accelerate extinction of conditioned taste aversion. Some intravenous anesthetic agents including propofol is known to induce anterograde and retrograde amnesia. We evaluated whether propofol affect the long-term memory formed by the conditioned taste aversion (CTA) paradigm. Rats were allowed a 4h access to water through the experiments. After preconditioning water intake, the rats were offered 0.1% sodium saccharin (Sac) as conditioned stimulus (CS) for 20 min. An intraperitoneal (i.p.) injection of several concentrations (0.5-100 mg/kg) of propofol 10 min after Sac exposure was followed by an i.p. injection of 0.15M LiCl (2% of body weight) as unconditioned stimulus (US) 30 min after CS-exposure. The volumes of intake of Sac for 20 min were measured on the successive 4 days. The rats, which acquired CTA by every CS-US paradigm, strongly avoided Sac on the first test day after conditioning and maintained the avoidance for 3 days. However, when subhypnotic dose of propofol was injected before LiCl-injection, Sac intake abruptly increased on the second test day and the almost complete extinction occurred on the third test day after conditioning. The extinction process of CTA was barely affected by hypnotic dose of propofol. These results suggest that propofol affects the retention mechanism of the CTA memory in a dose-dependent manner. Subhypnotic dose of propofol may affect the sub-cellular process of the memory consolidation in CTA.

Anesthetics, Intravenous↗
PubMed2003

Propofol for procedural sedation in children in the emergency department.

STUDY OBJECTIVE: We determine the safety and efficacy of propofol sedation for painful procedures in the emergency department (ED). METHODS: A consecutive case series of propofol sedations for painful procedures in the ED of a tertiary care pediatric hospital from July 2000 to July 2002 was performed. A sedation protocol was followed. Propofol was administered in a bolus of 1 mg/kg, followed by additional doses of 0.5 mg/kg. Narcotics were administered 1 minute before propofol administration. Adverse events were documented, as were the sedation duration, recovery time from sedation, and total time in the ED. RESULTS: Three hundred ninety-three discrete sedation events with propofol were analyzed. Procedures consisted of the following: fracture reductions (94%), reduction of joint dislocations (4%), spica cast placement (2%), and ocular examination after an ocular burn (0.3%). The median propofol dose was 2.7 mg/kg. Ninety-two percent of patients had a transient (<or=2 minutes) decrease in systolic blood pressure without clinical signs of poor perfusion. Nineteen (5%) patients had hypoxia, 11 (3%) patients required airway repositioning or jaw-thrust maneuvers, and 3 (0.8%) patients required bag-valve-mask ventilation. No patient required endotracheal intubation. CONCLUSION: Propofol sedation is efficacious and can be used safely in the ED setting under the guidance of a protocol. Transient cardiopulmonary depression occurs, which requires vigilant monitoring by highly skilled practitioners. Propofol is well suited for short, painful procedures in the ED setting.

Adjuvants, Anesthesia↗
PubMed2003

Growth of microorganisms in propofol and methohexital mixtures.

PURPOSE: The purpose of this study was to evaluate the growth of 4 different microorganisms in propofol, methohexital, and 1:1 and 1:3 mixtures of propofol and methohexital. MATERIALS AND METHODS: The microbial growth of Staphylococcus aureus, Pseudomonas aeruginosa, Candida albicans, and Escherichia coli in 1:1 and 3:1 mixtures of methohexital and 2 types of propofol was measured for 48 hours after mixing the solutions. Two of the 4 test solutions were composed of 1% methohexital combined with Diprivan (AstraZeneca Pharmaceuticals, Wilmington, DE), which uses EDTA as a microbial growth inhibitor. The growth of the same 4 microorganisms was also evaluated in 1:1 and 3:1 mixtures of 1% methohexital and a recently introduced generic propofol marketed by Baxter Pharmaceuticals (Deerfield, IL) that uses sodium metabisulfite as a preservative. RESULTS: Combining either Diprivan or generic propofol with methohexital in a 1:1 or 1:3 mixture ratio resulted in a solution that, like methohexital alone, significantly resisted the growth of C albicans, E coli, S aureus, and P aeruginosa for 48 hours. CONCLUSION: The results of our study suggest that 1:1 and 1:3 mixtures of propofol (either Diprivan or generic propofol) and methohexital behave similarly to methohexital alone by resisting growth of the microorganisms studied over the 48-hour time period. If, as has been reported elsewhere, the mixture of these 2 agents results in a solution with desirable anesthetic properties, its ability to resist microbial growth becomes clinically significant by extending the shelf-life of propofol in these mixtures.

Analysis of Variance↗
PubMed1996

Effects of sedation with midazolam or propofol on cognition and psychomotor functions.

PURPOSE: The study compared the effects of midazolam and propofol on explicit and implicit memory, cognition, and psychomotor function in patients undergoing oral surgical procedures with local anesthesia and conscious sedation. METHODS: Twenty-eight patients were tested in a randomized, double-blind study. Patients were randomly allocated to one of two groups. One group received a bolus dose of midazolam, 0.1 mg/kg, followed by a continuous infusion of saline. The other group received a bolus dose of propofol, 1.0 mg/ kg, followed by a continuous infusion of propofol, 65 micrograms/kg/min. Subjective rating questionnaires and tapping, memory, and Digit Symbol Substitution tests were administered. Testing was done at baseline, 10 minutes after the drugs were given, 10 minutes after surgery ended and 10 minutes later. RESULTS: The midazolam and propofol groups did not differ significantly on any demographic variables. Both drugs produced mental and physical sedation, which did not become substantially attenuated during the time studied. Both tranquilization and attitudes or other feelings showed smaller drug effects than mental and physical sedation. Tapping was decreased by both drugs 10 minutes after treatment, but not postsurgery. Performance on the Digit Symbol Substitution test was below baseline levels for both drugs at 10 minutes after treatment, but only for midazolam in the postsurgery assessment; at 10 minutes after treatment, propofol was associated with poorer performance than midazolam. Immediate and delayed explicit recall were impaired by both drugs 10 minutes after treatment. Immediate and delayed recall were lower for midazolam than propofol postsurgery, but only the difference on immediate recall was significant. Implicit memory was spared by both drugs. CONCLUSIONS: Midazolam and propofol generally produced equivalent impairments, but the duration of the effects of propofol was shorter. Unlike explicit memory, implicit memory resisted impairment.

Adult↗
PubMed2001

Propofol (Diprivan-EDTA) counteracts oxidative injury and deterioration of the arterial oxygen tension during experimental septic shock.

PURPOSE: Human septic shock can be replicated in the endotoxaemic pig. Endotoxaemia causes a multitude of events, including reduced PaO(2) and increased lipid peroxidation. This study was designed to evaluate the possible effects of a commonly used anaesthetic drug with known antioxidant properties (propofol) during porcine endotoxaemia. METHODS: Ten pigs were anaesthetised and given a 6 h E. coli endotoxin infusion. The animals received, randomly, a supplementary continuous infusion of propofol emulsion (containing 0.005% EDTA) or the corresponding volume of vehicle (controls). Pathophysiologic responses were determined. Non-enzymatic (by measuring plasma 8-iso-PGF(2 alpha) and enzymatic (by measuring plasma 15-keto-dihydro-PGF(2 alpha)) lipid peroxidations were evaluated. Plasma levels of the endogenous antioxidants alpha- and gamma-tocopherols, were also analysed. RESULTS: Endotoxaemia increased plasma levels of 8-iso-PGF(2 alpha) (1st-4th h) and 15-keto-dihydro-PGF(2 alpha) (1st-4th h) significantly more in controls than in the propofol+endotoxin group. PaO(2) was significantly less affected by endotoxin in the propofol treated animals (2nd-4th h). Mean arterial pressure (4th-6th h) and systemic vascular resistance (6th h) were reduced significantly more by endotoxin among the propofol-treated animals. Vitamin E (alpha-tocopherol) increased in all animals, significantly more in the propofol+endotoxin group (1/2-6th h) than in the control group. CONCLUSIONS: Propofol reduced endotoxin-induced free radical mediated and cyclooxygenase catalysed lipid peroxidation significantly. The implication is that propofol counteracts endotoxin-induced deterioration of PaO(2).

Anesthetics, Intravenous↗
PubMed2000

The effects of propofol on normal and hypercholesterolemic isolated rabbit heart.

The aim of the present study was to compare the effects of propofol on cardiac contractile force in normal and hypercholesterolemic isolated rabbit hearts. While one group was fed with standard chow pellets (150 g/day), the other group received cholesterol (1% w/w) in addition to the same amount of rabbit chow pellets during 1 month. Hearts from standard-fed rabbits were given intralipid solvent or 25, 50 and 100 microM propofol by infusion. Hypercholesterolemic rabbit hearts were administered 25, 50 and 100 microM propofol by infusion. All concentrations of propofol did not result in any significant change of the heart rates (HR) in two groups. Propofol (25, 50 and 100 microM) infusion induced a concentration- and time-dependent inhibition in left ventricular pressure (LVP) in standard chow diet group (P<.05,.05 and.05, respectively). In hypercholesterolemic rabbit hearts, 25 and 50 microM propofol infusion developed a significant inhibition in LVP when compared with the standard chow diet group (P<.05 and.05, respectively). Propofol (100 microM) infusion developed a significant increase in LVP after 20 min in hypercholesterolemic rabbit hearts when compared with normal rabbit hearts (P<.05). Supratherapeutic concentration of propofol might have cardioprotective effect on hypercholesterolemic rabbit hearts.

Anesthetics, Intravenous↗
PubMed1999

Comparison of the intravenous reinforcing effects of propofol and methohexital in baboons.

Propofol is a widely used intravenous anesthetic that can directly activate and positively modulate the GABA(A)-receptor. Propofol is not currently regulated under the USA Controlled Substances Act. The present study evaluated the intravenous reinforcing effects of propofol compared to the intravenous barbiturate anesthetic methohexital in baboons using a procedure in which doses of the test drug were substituted for a standard cocaine dose. Drug or vehicle was available for self-injection during daily 5.5-h sessions under a fixed-ratio 120 or 160 schedule of reinforcement. A 40-min timeout after each injection limited the maximum of injections per session to eight. Food pellets were available continuously during the session under a fixed ratio 10 schedule of reinforcement. Self-injection of cocaine (0.001-0.32 mg/kg/injection) and vehicle was characterized first. Cocaine maintained self-injection in a dose-dependent manner, with peak injections maintained by 0.32 mg/kg. Vehicle and each dose of propofol (0.1-1.0 mg/kg/injection) and methohexital (0.01-1.0 mg/kg/injection) were substituted for 0.32 mg/kg cocaine for at least 10 sessions. Propofol and methohexital maintained self-injection greater than vehicle in all three baboons, and these effects were dose dependent. Methohexital maintained peak mean levels of self-injection that were >6 injections/day at doses of 0.56 and 1.0 mg/kg, and did not alter food intake systematically. Propofol maintained peak mean levels of self-injection at 1.0 mg/kg that ranged from 2.2 to >6 injections/day across the baboons. Food intake was increased slightly above vehicle levels by propofol self-injection in two baboons, and was decreased in the third baboon. These data indicate that propofol, like methohexital, can function as a positive reinforcer.

Anesthetics, Intravenous↗
PubMed1991

[Use of propofol in 1350 anesthetized patients for electroconvulsive therapy].

Propofol was used for 1,350 sessions of electro-convulsive therapy (ECT). After 0.5 mg of intravenous atropine, patients received 1 to 1.5 mg.kg-1 bolus of propofol over a period of 20 seconds or less. This was convenient for loss of the eye-lash reflex. A bolus of 15 to 20 mg suxamethonium was given, in non allergic patients, to prevent trauma from the seizure. The patient was hyperventilated with pure oxygen through a facial mask. The electric shock was delivered bitemporally after a dental protection had been inserted. For each patient, the following data were noted: sex, use of tricyclic antidepressant drugs, atopy, amount of administered propofol and the effective intensity of the electric shock. The 99 patients were given 16.27 +/- 14 ECT sessions. Among them 26 took antidepressant drugs and 34 were atopic. There was no difference, except for weight, between the 25 men and 74 women. The mean dose of propofol was 1.37 +/- 0.3 mg.kg-1. The dose decreased with increasing age. There was no statistical relationship between the amount of propofol and intensity of the electric shock required to set off a seizure. The use of antidepressant drugs, and atopy did not influence the required amount of propofol. Speed of injection seemed to be the determining factor for narcosis with low doses of propofol. Hyperoxia and hypocapnia induced by hyperventilating with pure oxygen seemed to facilitate occurrence and duration of seizures. Although propofol has been said to reduce the length of seizures, there is controversy concerning the ECT efficacy criteria.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1987

[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)

Aged↗
PubMed2002

The effects of thiopental and generic and nongeneric propofol on respiratory resistance during anesthetic induction in patients with reactive airways.

STUDY OBJECTIVE: To demonstrate a favorable effect of propofol on respiratory system resistance during anesthetic induction, and to determine if generic propofol causes adverse effects on respiratory resistance. DESIGN: Randomized pilot study. SETTING: Anesthetic induction for elective surgery. PATIENTS: 27 consenting ASA physical status II and III patients with reactive airways (positive smoking history or chronic obstructive pulmonary disease), but not receiving bronchodilator therapy. INTERVENTIONS: Patients were randomized equally to one of three anesthetic induction (and maintenance) drugs: sodium thiopental, 5 mg/kg (25 microg/kg/min), generic or nongeneric propofol, 1.25 mg/kg (50 microg/kg/min). They received preinduction midazolam and fentanyl (2 mg and 150 microg) and intravenous lidocaine (0.5 mg/kg). After anesthetic induction, tracheal intubation was established, and predetermined settings for mechanical ventilation were initiated. MEASUREMENTS: Immediately after intubation, a sensor was placed on the 8-mm endotracheal tube to detect baseline airway pressure and flow. During maintenance, repeat measurements of pressure and flow were obtained at 2.5-minute intervals for 10 minutes. Respiratory system resistance was derived off-line using the isovolumetric technique. MAIN RESULTS: Patients were similar across groups. The respiratory resistance measured after anesthetic induction did not differ among groups. During the maintenance infusion of thiopental or propofol, respiratory resistance increased gradually across all groups. There was no difference in the response of respiratory resistance either at induction or during the 10-minute maintenance between the generic and the nongeneric propofol groups. CONCLUSIONS: In contrast to earlier reports, this pilot study was unable to document a difference in the respiratory resistance in patients induced with thiopental or propofol. In addition, we were unable to demonstrate any different respiratory responses between generic propofol, containing sodium metabisulfite preservative, and nongeneric propofol.

Airway Resistance↗
PubMed1996

Propofol and alfentanil for sedation during placement of retrobulbar block for cataract surgery.

STUDY OBJECTIVE: To determine if the addition of alfentanil to propofol is more effective than propofol alone to provide adequate conditions for placement of a retrobulbar block prior to cataract surgery. DESIGN: Randomized, double-blinded study. SETTING: Outpatients at a university hospital. PATIENTS: 40 adult ASA physical status I, II, and III outpatients scheduled for elective cataract surgery. INTERVENTIONS: Patients were randomly assigned to receive one of four drug combinations prior to the placement of a retrobulbar block: Group 1, propofol alone; Group 2, alfentanil 5 micrograms/kg plus propofol; Group 3, alfentanil 10 micrograms/kg plus propofol; Group 4, alfentanil 15 micrograms/kg plus propofol. All patients were preoxygenated by face mask for two minutes prior to drug administration. The quality of conditions for block placement were determined by: (1) assessing the amount of movement by the patients while the block needle was in place, (2) cooperativeness of the patients during the operation, (3) hemodynamic side effects, (4) incidence and severity of respiratory depression, (5) incidence of nausea and vomiting, (6) recall of placement of the block, and (7) time to discharge from the hospital. MEASUREMENTS AND MAIN RESULTS: The addition of alfentanil to propofol for sedation prior to placement of the retrobulbar block resulted in a dose-dependent reduction in movement by the patients. However, the highest dose of alfentanil (15 micrograms/kg) resulted in the greatest frequency (40% of the patients in this group) of respiratory depression (SpO2 < 90%). All patients were cooperative during the operation and responsive to verbal command within 5 minutes of placement of the block. In addition, all of the patients denied being nauseated, having vomited, or recalling block placement in the recovery room or the next day. CONCLUSIONS: The combination of alfentanil and propofol may be used to sedate patients in order to limit movement and provide a cooperative, alert patient with stable hemodynamics and limited respiratory depression during placement of retrobulbar block prior to ophthalmic surgery. However, excessive dosage of these drugs may result in hazardous respiratory depression in this patient population.

Aged↗
PubMed1999

The optimal effective concentration of lidocaine to reduce pain on injection of propofol.

STUDY OBJECTIVE: To determine the optimal concentration of lidocaine that reduces pain on injection of a propofol-lidocaine mixture. DESIGN: Prospective, randomized, double-blinded, clinical investigation. SETTING: Medical center, university teaching hospital. PATIENTS: 240 ASA physical status I and II female outpatients, aged 21 to 65 years, undergoing dilation and curettage with propofol for anesthesia induction. INTERVENTIONS: Patients were randomized to one of four groups in double-blinded fashion. In Group A (control), patients were given propofol containing normal saline; in Group B, Group C, and Group D, patients received propofol containing 0.05% lidocaine (Group B), propofol containing 0.1% lidocaine (Group C), and propofol containing 0.2% lidocaine (Group D) for induction. MEASUREMENTS AND MAIN RESULTS: The incidence of pain on injection of propofol was significantly decreased in Group C and Group D (8.3% and 10.0%, respectively) in comparison to the control group (91.7%) (p < 0.001). Although the result in Group B (76.7%) was better than that in the control group, the difference was not statistically significant. No significant difference was seen between Group C and Group D. CONCLUSIONS: The optimal effective concentration of lidocaine, which decreased the incidence of pain caused by propofol injection, was 0.1% in the currently studied population.

Adult↗
PubMed2003

Propofol versus remifentanil for monitored anaesthesia care during colonoscopy.

BACKGROUND AND OBJECTIVE: We conducted an open, prospective, randomized study to compare the efficacy, safety and recovery characteristics of remifentanil or propofol during monitored anaesthesia care in patients undergoing colonoscopy. METHODS: Forty patients were randomly assigned to receive either propofol (1 mg kg(-1) followed by 10 mg kg (-1) h(-1), n = 20) or remifentanil (0.5 microg kg(-1) followed by 0.2 microg kg(-1) min(-1), n = 20). The infusion rate was subsequently adapted to clinical needs. RESULTS: In the propofol group, arterial pressure and heart rate decreased significantly from the baseline. These variables remained unchanged in the remifentanil group, but hypoventilation occurred in 55% of patients. Early recovery was delayed in the propofol group (P < 0.002). Recovery of cognitive and psychomotor functions was faster in the remifentanil group. Fifteen minutes after anaesthesia, the Digit Symbol Substitution Test score was 28.6 +/- 12.8 versus 36.2 +/- 9.4 and the Trieger Dot Test score was 25.6 +/- 8.1 versus 18.7 +/- 4.1 in the propofol and remifentanil groups, respectively (both P < 0.05). Patient satisfaction, using a visual analogue scale, was higher in the propofol group (96 +/- 7 versus 77 +/- 21, P < 0.001). CONCLUSIONS: Remifentanil proved efficient in reducing pain during colonoscopy. Emergence times were shorter and the recovery of cognitive function was faster with remifentanil compared with propofol. Remifentanil provided a smoother haemodynamic profile than propofol; however, the frequent occurrence of remifentanil-induced hypoventilation requires the cautious administration of this agent.

Adolescent↗
PubMed2005

A combination of lidocaine and nitrous oxide in oxygen is more effective in preventing pain on propofol injection than either treatment alone.

BACKGROUND AND OBJECTIVE: Propofol is an intravenous (i.v.) anaesthetic agent that possesses many of the qualities of an ideal anaesthetic agent. The most significant side-effect associated with propofol is pain on injection. Despite optimal therapy, the incidence of pain on propofol injection remains a problem. This prospective, randomized, double blinded study evaluated the effect of three different treatment strategies in decreasing pain on propofol injection. METHODS: We studied 102 adult, ASA I-II patients, scheduled for elective surgical procedures. Combination of i.v. lidocaine and nitrous oxide (N2O) in oxygen (O2) inhalation pre-treatment was compared with either treatment alone in the prevention of pain on propofol injection. A standard propofol injection technique and scoring system, to measure the pain on injection was used. RESULTS: Demographic variables were similar between the groups. The incidence of no pain on propofol injection was similar in the lidocaine and N2O groups (63.6% vs. 57.5%) (95% confidence interval (CI): 0.17-0.29, P = 0.61). Combination therapy was associated with a greater incidence of no pain on injection (84% vs. 63.6%) (95% CI: 0.06-0.48, P = 0.04). CONCLUSION: Combination of i.v. lidocaine and N2O in O2 inhalation pre-treatment is more effective than either treatment alone in decreasing pain on propofol injection.

Adolescent↗
PubMed2005

Propofol sedation with fentanyl or midazolam during oesophagogastroduodenoscopy in children.

BACKGROUND AND OBJECTIVE: Sedation is commonly used to facilitate diagnostic procedures in children. The aim of our study was to investigate sedation in children using propofol alone or combined with fentanyl or midazolam with regard to efficacy, adverse reactions or side-effects related to the drugs, ease of operation for the endoscopist, and time to discharge from the post-anaesthesia care unit. METHODS: We prospectively studied 240 children, aged 1-12 yr of age, undergoing endoscopic procedures of the upper gastrointestinal tract. The patients were given an oral premedication with midazolam (0.5 mg kg(-1)) and were then randomly allocated to one of the three study groups: propofol alone (Group P), propofol with fentanyl 1 mug kg-1 (Group PF) or propofol with midazolam 0.1 mg kg(-1) (Group PM). Additional doses of propofol given during the procedure were recorded. Adequacy of sedation and ease of procedure (easy, adequate, impossible) were evaluated by the endoscopist, who was blinded as to the drugs used. RESULTS: The duration of the procedure and the recovery period were similar in the three groups. The number of patients requiring supplemental doses of propofol to permit safe completion of gastroscopy was 31 in Group P (=39%; eight of these required two additional doses), 14 in Group PM (=18%), and 11 in Group PF (=13%) (P < 0.05). There was a lower incidence of adverse events in Group PM and in Group PF than in Group P (P < 0.05). CONCLUSIONS: Propofol in combination with fentanyl or midazolam gives better sedation and ease of endoscopy than propofol alone.

Anesthesia Recovery Period↗
PubMed2006

The 'propofol infusion syndrome': the facts, their interpretation and implications for patient care.

AstraZeneca (the manufacturer of Diprivan) presents its review of the history of the so-called 'propofol infusion syndrome', highlighting the difficulties in analysing the incomplete information available. Theories as to its causality are presented and discussed; these include mitochondrial toxicity, mitochondrial defects, impaired tissue oxygenation and carbohydrate deficiency. A review of published and confidential safety data is presented and discussed; it concludes that the major risk factors for its development appear to be poor oxygen delivery, sepsis, serious cerebral injury and high propofol dosage. In some reports an increasing lipaemia was noted and was likely to be due to a failure of hepatic lipid regulation, possibly related to poor oxygenation and/or possibly a lack of glucose. In some cases an increasing lipaemia was the first indication of impending 'propofol infusion syndrome' onset and it should not be viewed as a benign sign. The lipaemia can lead to sequestration of propofol into the lipid phase, leading to lowered free propofol levels and apparent insensitivity to propofol. In conclusion AstraZeneca advocates good haemodynamic and oxygen delivery management, adequate glucose provision, adherence to recommended propofol dosing regimes together with active management of lipaemias to both prevent and treat 'propofol infusion syndrome'.

Adolescent↗
PubMed1999

The effect of ketamine on clinical endpoints of hypnosis and EEG variables during propofol infusion.

BACKGROUND: We studied the effect of variable doses of ketamine on the endpoints of hypnosis, e.g., unresponsiveness to verbal commands (UVC), loss of eyelash reflex (LER), and inhibition of body movement response with or without sneezing to nasal membrane stimulation (INBMR), and processed EEG variables, e.g., bispectral index (BIS), 95% spectral edge frequency (SEF) and median frequency (MF) during propofol infusion. METHODS: Forty-eight patients received either propofol infusion, 30 mg.kg-1.h-1 (Group P; n = 12) or ketamine bolus, 0.25, 0.5 or 0.75 mg i.v., followed by propofol infusion, 30 mg.kg-1.h-1 + variable dose ketamine infusion, 0.25, 0.5 or 0.75 mg.kg-1.h-1 (Groups PK0.25, PK0.5 and PK0.75; n = 12 each) until UVC, LER and INBMR. BIS, 95% SEF and MF values were monitored and recorded at the endpoints of hypnosis. Propofol and ketamine concentrations were measured at INBMR. RESULTS: Propofol infusion, 30 mg.kg-1.h-1, induced UVC, LER and INBMR at BIS: 65 +/- 2, 63 +/- 9 and 33 +/- 7; 95% SEF: 17 +/- 3, 17 +/- 4 and 14 +/- 3; and MF values of 5 +/- 2, 5 +/- 3 and 3 +/- 2, respectively. With adjunctive ketamine (Groups PK0.5 and PK0.75), the hypnotic endpoints were achieved at higher BIS and 95% SEF values and lower propofol doses and concentrations as compared to Groups P and PK0.25 (9.9 +/- 5.8 and 9.4 +/- 3.4 vs. 13.4 +/- 4.5 and 14 +/- 5.8 micrograms.ml-1). CONCLUSIONS: Our results suggest additive interaction between propofol and ketamine (Groups PK0.5 and PK0.75) for achieving the hypnotic endpoints; however, ketamine did not depress the EEG variables in proportion to its hypnotic effect. The paradoxically higher BIS and 95% SEF values at the hypnotic endpoints may be due to lower propofol concentrations and/or no effect of ketamine on the EEG variables.

Adult↗
PubMed2000

The effect of sedation on weaning following coronary artery bypass grafting: propofol versus oxycodone-thiopental.

BACKGROUND: Propofol has been advocated for sedation in intensive care because of superior recovery characteristics. We hypothesised that the use of two totally different sedation methods after coronary artery bypass grafting should result in differences not only in extubation time, but also in breathing pattern and gas exchange during weaning and after extubation. METHODS: Thirty patients participated in this randomised and controlled study. We used propofol infusion and oxycodone-thiopental bolus dosage, titrated to sedation level 4 or 5 according to Ramsey. Weaning was performed using protocol-based pressure support trials. RESULTS: Total (SD) fentanyl dose during operation was 33 (6) microg x kg(-1) for propofol and 34 (6) microg x kg(-1) for oxycodone-thiopental (ns). The target sedation was achieved equally with both methods. The time from admission to intensive care unit to extubation was 494 (100) min for propofol and 521 (98) min for oxycodone-thiopental (ns). Weaning times were 63 (24) min and 112 (63) min in the propofol and oxycodone-thiopental groups, respectively (P<0.05). Breathing frequency increased and tidal volume decreased from weaning to 2 h postextubation. CONCLUSION: Propofol infusion and oxycodone-thiopental bolus dosages, titrated to the same sedation end point, resulted in similar time from admission to extubation, although the weaning period was shorter in the propofol group. In terms of breathing pattern, gas exchange, blood gases and haemodynamics, the methods were similar. Propofol, despite its attractive pharmacological profile, may offer no clinical benefit in short-term sedation after a moderate dose fentanyl anaesthesia in cardiac surgery.

Carbon Dioxide↗