Propofol and intralipid cause creaming of serum from critically ill patients

Propofol Use in Israeli PICUs

OBJECTIVES

In Israel, the recommendation for the use of propofol is age limited. Furthermore, procedural sedations involving propofol must be performed only by anesthesiologists. Propofol is frequently used in the PICUs in Israel.

DESIGN

Questionnaire survey.

SETTING

PICUs in Israel.

SUBJECTS

None.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Physicians from 13 PICUs (86.6%) responded to the questionnaire. Propofol was used for induction, procedural sedation, and ongoing ICU sedation in 100%, 70%, and 12% of cases, respectively. Eighty-eight percent of the participants limited the duration of propofol infusion to 24 hours at a dose of less than or equal to 4 mg/kg/1 hr, but 40% administered propofol as needed without specifying an upper dose limit. Twenty-five percent encountered adverse effects such as apnea, desaturation, and bradycardia, but only two of the participants suspected propofol infusion syndrome, each in one patient. All the participants agreed to expand the indications for propofol use in the pediatric age group. Ketamine was the drug mostly used instead of propofol (50%), followed by fentanyl (30%), midazolam (30%), and remifentanil (5%). Apart from anesthesiologists, PICU physicians support the use of propofol by physicians who have the technical skills for rapid-sequence intubation and advanced airway management.

CONCLUSIONS

Off-label use of propofol is an accepted practice in Israeli PICUs. Propofol has a unique profile that makes it an attractive sedative agent in many clinical settings. PICU physicians may want to prescribe it, at least for short periods and at low doses.

Comparison of Methods for Intravenous Infusion of Fat Emulsion During Extracorporeal Membrane Oxygenation

STUDY OBJECTIVES

To characterize the effects of infusing fat emulsion during neonatal extracorporeal membrane oxygenation (ECMO) by comparing results from patients receiving fat emulsion through the ECMO circuit with those receiving fat emulsion through separate intravenous access. A second goal was to identify the optimal route for administration.

DESIGN

Prospective, randomized, open-label trial.

SETTING

Neonatal intensive care unit in a 106-bed quaternary care pediatric hospital.

SUBJECTS

Nine neonates receiving ECMO who required intravenous nutrition. Intervention. Patients received 1-3 g/kg/day of fat emulsion into either the ecmo circuit or separate intravenous access.

MEASUREMENTS AND MAIN RESULTS

The ECMO circuit and samples of blood were evaluated hourly for phase separation, layering out of the emulsion from blood, agglutination, and blood clots. After completion, the oxygenators were dissected and examined. Data were compared with an unpaired t test. The characteristics of the groups were similar, except for a higher mean weight in the ECMO circuit group (3.6 +/- 0.3 kg vs 2.8 +/- 0.4 kg, p=0.03). The mean +/- SD triglyceride level during the study was 87 +/- 79 mg/dl, with no significant difference between the two groups. Two patients in each group had elevated triglyceride levels. No cases of phase separation occurred. In the five patients who received fat emulsion into the ECMO circuit, three had layering out of the emulsion and agglutination, and all developed clots in the circuit despite adequate anticoagulation. Of the four patients in the intravenous-access group, one had layering and agglutination, and two had blood clots.

CONCLUSIONS

Although both methods were associated with layering out, agglutination, and clot formation, these effects occurred more frequently with administration into the ECMO circuit, particularly in areas of stasis. This may result in disruption of normal ECMO blood flow and impaired delivery of calories. Fat emulsion should therefore be administered through separate intravenous access during ECMO whenever possible.

Pharmacological characteristics and side effects of a new galenic formulation of propofol without soyabean oil*

We compared the pharmacokinetics, pharmacodynamics and safety profile of a new galenic formulation of propofol (AM149 1%), which does not contain soyabean oil, with a standard formulation of propofol (Disoprivan 1%). In a randomised, double-blind, cross-over study, 30 healthy volunteers received a single intravenous bolus injection of 2.5 mg.kg-1 propofol. Plasma propofol levels were measured for 48 h following drug administration and evaluated according to a three-compartment model. The pharmacodynamic parameters assessed included induction and emergence times, respiratory and cardiovascular effects, and pain on injection. Patients were monitored for side effects over 48 h. Owing to a high incidence of thrombophlebitis, the study was terminated prematurely and only the data of the two parallel treatment groups (15 patients in each group) were analysed. Plasma concentrations did not differ significantly between the two formulations. Anaesthesia induction and emergence times, respiratory and cardiovascular variables showed no significant differences between the two treatment groups. Pain on injection (80 vs. 20%, p < 0.01) and thrombophlebitis (93.3 vs. 6.6%, p < 0.001) occurred more frequently with AM149 than with Disoprivan. Although both formulations had similar pharmacokinetic and pharmacodynamic profiles the new formulation is not suitable for clinical use due to the high incidence of thrombophlebitis produced.

Death related to propofol use in an adult patient

OBJECTIVE

To report an adult trauma patient fatality related to propofol administration.

DESIGN

Retrospective case review.

SETTING

Trauma intensive care unit (ICU) in a level one trauma center.

PATIENT

An 18-yr-old man involved in a motor vehicle crash.

INTERVENTIONS

Treatment for multiple trauma injuries and propofol sedation.

MEASUREMENTS AND MAIN RESULTS

Posttrauma ICU monitoring was performed. The patient developed cardiac arrhythmia, metabolic acidosis, and cardiac failure, which resulted in death.

CONCLUSION

Death related to propofol infusion can occur in adults as well as in pediatric patients.

Propofol infusion syndrome in children

The use of propofol infusions to sedate children in intensive care units has decreased after reports of deaths from myocardial failure. More recently it has been suggested that propofol might have been prematurely condemned. Information about 18 children who had received propofol infusions and suffered serious unwanted effects was used to define their common features. Three of the deaths occurred in one intensive care unit where propofol infusions had been used between 1987 and 1993. During this period 44 children with respiratory tract infections had been admitted to this unit and sedated for at least 48 h. Nine had received long-term (> 48 h), high-dose (> 4 mg.kg-1.h-1) propofol infusions and three had developed progressive myocardial failure and died. There was a significant association between receiving a long-term, high-dose propofol infusion and developing progressive myocardial failure (Fisher's Exact Test, two-tailed hypothesis, P = 0.0128) although a causative relationship could not be proved.

Propofol 2% in critically ill patients: effect on lipids

OBJECTIVE

To investigate the concentrations of triglyceride, cholesterol, and high-density lipoprotein during a 50-hr infusion of 2% propofol, starting within 24 hrs of admission to the intensive care unit (ICU).

DESIGN

Prospective, clinical study.

SETTING

ICU, university hospital.

PATIENTS

Thirty adult patients, who were ventilated and expected to be sedated for >2 days, were studied for 50 hrs, beginning at 1800 hrs on the first day of ICU admission.

MEASUREMENTS AND MAIN RESULTS

Triglyceride, cholesterol, and high-density lipoprotein were measured at 2000, 0400, and 0800 hrs. Tumor necrosis factor (TNF)-alpha, interleukin (IL)-6, and C-reactive protein were measured at 2000 hrs. Median cholesterol and high-density lipoprotein concentrations were at the low end of the normal range. In seven patients, peak triglyceride concentrations were >3 mmol/L up to a maximum of 4.83 mmol/L. Although there was no statistical difference in lipid concentrations between days 1 and 2, there was an apparent pattern of increasing triglyceride concentrations. There was a correlation between peak triglyceride concentration and total propofol consumption, but there was no correlation between lipids and age, gender, or Acute Physiology and Chronic Health Evaluation II scores. There was a direct correlation between triglyceride and C-reactive protein concentrations, and an inverse correlation between cholesterol and C-reactive protein. Twenty-two patients had evidence of TNF and 11 patients had an IL-6 of >1000 pg/mL, but there was no relationship between concentrations of cytokines and triglycerides in plasma.

CONCLUSIONS

Infusion of 2% propofol to critically ill patients over a 50-hr period does not result in a significant increase in triglyceride concentrations. Mean cholesterol and high-density lipoprotein concentrations were low throughout the study period. There was a significant direct correlation between triglyceride and C-reactive protein and an inverse correlation between cholesterol and C-reactive protein, suggesting that the changes in lipids in critically ill patients may be partly attributable to the acute-phase response.

Anaesthetic considerations for children undergoing stereotactic radiosurgery

An anaesthetic case report of children undergoing stereotactic radiosurgery is presented, with a review of the inherent unique anaesthetic challenges. Twelve stereotactic radiosurgery procedures performed at The Prince of Wales Hospital, Sydney, were retrospectively reviewed. Despite differences in approach by individual anaesthetists to managing these children, an overall safe sequence may be evolved. The use of stereotactic radiosurgery for paediatric neuropathology is reviewed. The potential anaesthetic problems related to the paediatric patient and the peculiarities of the procedure are discussed and related to our series.

Propofol. An overview of its pharmacology and a review of its clinical efficacy in intensive care sedation

Propofol is a phenolic derivative that is structurally unrelated to other sedative hypnotic agents. It has been used extensively as an anaesthetic agent, particularly in procedures of short duration. More recently it has been investigated as a sedative in the intensive care unit (ICU) where it produces sedation and hypnosis in a dose-dependent manner. Propofol also provides control of stress responses and has anticonvulsant and amnesic properties. Importantly, its pharmacokinetic properties are characterised by a rapid onset and short duration of action. Noncomparative and comparative trials have evaluated the use of propofol for the sedation of mechanically ventilated patients in the ICU (postsurgical, general medical, trauma). Overall, propofol provides satisfactory sedation and is associated with good haemodynamic stability. It produces results similar to or better than those seen with midazolam or other comparator agents when the quality of sedation and/or the amount of time that patients were at adequate levels of sedation are measured. Patients sedated with propofol also tend to have a faster recovery (time to spontaneous ventilation or extubation) than patients sedated with midazolam. Although most studies did not measure time to discharge from the ICU, propofol tended to be superior to midazolam in this respect. In a few small trials in patients with head trauma or following neurosurgery, propofol was associated with adequate sedation and control of cerebral haemodynamics. The rapid recovery of patients after stopping propofol makes it an attractive option in the ICU, particularly for patients requiring only short term sedation. In short term sedation, propofol, despite its generally higher acquisition costs, has the potential to reduce overall medical costs if patients are able to be extubated and discharged from the ICU sooner. Because of the potential for hyperlipidaemia and the development of tolerance to its sedative effects, and because of the reduced need for rapid reversal of drug effects in long term sedation, the usefulness of propofol in long term situations is less well established. While experience with propofol for the sedation of patients in the ICU is extensive, there are still areas requiring further investigation. These include studies in children, trials examining cerebral and haemodynamic outcomes following long term administration and in patients with head trauma and, importantly, pharmacoeconomic investigations to determine those situations where propofol is cost effective. In the meantime, propofol is a well established treatment native to benzodiazepines and/or other hypnotics or analgesics when sedation of patients in the ICU is required. In particular, propofol possesses unique advantages over these agents in patients requiring only short term sedation.