Propofol Infusion In Children Research Articles

Predictive performance of eleven pharmacokinetic models for propofol infusion in children for long-duration anaesthesia

BackgroundPredictive performance of eleven published propofol pharmacokinetic models was evaluated for long-duration propofol infusion in children. MethodsTwenty-one aged three–11 yr ASA I–II patients were included. Anaesthesia was induced with propofol or sevoflurane, and maintained with propofol, remifentanil, and fentanyl. Propofol was continuously infused at rates of 4–14 mg kg −1 h−1 after an initial bolus of 1.5–2.0 mg kg −1. Venous blood samples were obtained every 30–60 min for five h and then every 60–120 min after five h from the start of propofol administration, and immediately after the end of propofol administration. Model performance was assessed with prediction error (PE) derivatives including divergence PE, median PE (MDPE), and median absolute PE (MDAPE) as time-related PE shift, measures for bias, and inaccuracy, respectively. ResultsWe collected 85 samples over 270 (130) (88–545), mean (SD) (range), min. The Short model for children, and the Schüttler general-purpose model had acceptable performance (–20%≤MDPE ≤ 20%, MDAPE ≤ 30%, –4% h−1≤ divergence PE ≤ 4% h−1). The Short model showed the best performance with the maximum predictive performance metric. Two models developed only using bolus dosing (Shangguan and Saint-Maurice models) and the Paedfusor of the remaining nine models had significant negative divergence PE (≤–6.1% h−1). ConclusionsThe Short model performed well during continuous infusion up to 545 min. This model might be preferable for target-controlled infusion for long-duration anaesthesia in children.

Propofol effect on cerebral oxygenation in children with congenital heart disease.

Propofol is a short-acting, intravenously administered hypnotic agent which is used in procedural sedation in children. Propofol is known to decrease systemic vascular resistance, arterial blood pressure and can lead to desaturations and decreased systemic perfusion in children with cardiac shunting. This may result in a reduction in cerebral blood flow and oxygenation. Near-infrared spectroscopy (NIRS) can monitor cerebral tissue oxygenation in the frontal neocortex. The objective of our study was to measure the changes in cerebral oxygen and blood supply after Propofol infusion in children with congenital heart disease. Propofol infusion may reduce cerebral oxygenation in children with congenital heart disease. The study group consisted of 32 children (f:m=18:14), with median age of 49 (5-112) months and median weight of 15 (5-34) kg. We performed NIRS derived continuous measurement of cerebral oxygenation and cardiac output using Electrical velocimetry for 5min before and after sedation with Propofol (1-2mg/kg i.v.) for cardiac catheterization. Simultaneously, non-invasive arterial blood pressure and transcutaneous oxygen saturation were measured. Propofol sedation led to a significant decrease in mean arterial pressure (79±16 vs. 67±12mmHg) (p=0.01) and cardiac index (3.2±0.8 vs. 2.9±0.6ml/min/m(2)) (p=0.03). In contrast, cerebral tissue oxygenation index, increased significantly from 57±11 to 59±10% (p<0.05). Sedation with Propofol increased cerebral tissue oxygenation despite a decrease in cardiac index and arterial blood pressure. This may be caused by a decreased oxygen consumption of the sedated brain with intact cerebral auto-regulation.

Design and Clinical Evaluation of Robust PID Control of Propofol Anesthesia in Children

This paper describes the design of a robust proportional-integral derivative (PID) controller for propofol infusion in children and presents the results of clinical evaluation of this closed-loop system during endoscopic investigations in children age 6-17. The controller design is based on a set of models that describes the interpatient variability in the response to propofol infusion in the study population. The PID controller is tuned to achieve sufficient robustness margins for the identified uncertainty. 108 children were enrolled in this study, and anesthesia was closed-loop controlled in 102 of these cases. Clinical evaluation of the system shows that closed-loop control of both induction and maintenance of anesthesia in children based on the WAV <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">CNS</sub> index as a measure of clinical effect is feasible. A robustly tuned PID controller can accommodate the interpatient variability in children and spontaneous breathing can be maintained in most subjects.

34th Annual Scientific Meeting of the Association of Paediatric Anaesthetists of Great Britain and Ireland, 8?10 March 2007, Manchester. Paediatric total intravenous anaesthetic use: a nationwide study

Introduction: Propofol is widely used for induction and maintenance of anaesthesia in paediatric patients. Following the initial reports of deaths following prolonged high dose infusions on intensive care (1), the propofol infusion syndrome was described (2). The exact cause of this is still uncertain but consistent biochemical abnormalities have been described (3, 4). Initially the cases were all in children on intensive care units, but more recently cases have been reported in adults. Of greater concern to paediatric anaesthetists are the reports of deaths following propofol infusions in theatre (5, 6). We set out to define the current use of propofol infusions by Paediatric Anaesthetists within the UK. Methods: A list of names and addresses of paediatric anaesthetists was composed by contacting anaesthetic departments at the hospitals by telephone and asking for the names of their paediatric anaesthetists. An 18 question survey with an enclosed stamped, addressed envelope was posted to 388 consultant paediatric anaesthetists in 51 hospitals throughout the UK. The survey was re-submitted once to consultants who had not initially replied. The results were tabulated onto a database and analysed. Results: We received a total of 242 replies (63% of surveyed population), 240 of which regularly anaesthetised children. Within the last year 13% had used propofol infusions on children under 1, 31% in children 1–5 years, 41% in children 5–10 years and 46% in the over 10 s. The two most common surgical specialties with which propofol TIVA was used were ENT (n = 66), and orthopaedics (n = 53), the most common operations stated being middle ear surgery, muscle biopsy and scoliosis surgery. The reasons for using propofol in these patients were broad and included both anaesthetic and surgical considerations. 60 consultants questioned used propofol infusions in children at least monthly, 98 rarely and 72 never. Over 50% of replies believed that propofol infusions reduced the rate of postoperative nausea and vomiting in respect to inhalational techniques, less agreed that there was faster recovery time or time to discharge. Remifentanil was commonly used with propofol infusions but target controlled infusion devices were uncommonly used. The longest time anyone considered using propofol for was 72 h, although the mode of all positive responses was 6 h. The majority of people failed to give a maximum infusion rate. Conclusions: Propofol infusions are used widely throughout the UK for their perceived anaesthetic and surgical benefits. Given that there are well documented catastrophic, albeit rare side effects, it is surprising that there are no guidelines for infusions in theatre. Further work is required to elucidate the exact mechanism of propofol infusion syndrome to guide future anaesthetic practice. References 1 Parke TJ, Stevens JE, Rice AS et al. Metabolic acidosis and fatal myocardial failure after propofol infusion in children: five case reports. Br Med J 1992; 305: 613–616. 2 Bray RJ. Propofol infusion syndrome in children. Paediatr Anaes 1998; 8: 491–499. 3 Wolf AR, Weir P, Segar P, et al. Impaired fatty acid oxidation in propofol infusion syndrome. Lancet 2001; 357: 606–607. 4 Wolf AR, Potter F. Propofol infusion in children: when does an anesthetic tool become an intensive care liability? Paediatr Anaesth 2004; 14: 435–438. 5 Mehta N, DeMunter C, Habibi P et al. Short-term propofol infusions in children. Lancet 1999; 354: 866–867. 6 Kill C, Leonhardt A, Wulf H. Lacticacidosis after short-term infusion of propofol for anaesthesia in a child with osteogenesis imperfecta. Paediatr Anaesth 2003; 13: 823–826.

Desflurane increases cerebral blood flow velocity when used for rapid emergence from propofol anesthesia in children

Desflurane may be used to replace propofol at the end of anesthesia to facilitate rapid emergence. This study determined the effect of administering desflurane during emergence of anesthesia on middle cerebral artery blood flow velocity (Vmca) in children anesthetized with propofol. Thirty healthy children aged one to six years scheduled for orchidopexy or hypospadias repair under general anesthesia were enrolled. Anesthesia was maintained with a propofol infusion targeting an estimated serum level of 3 microg x mL(-1), remifentanil 0.2 microg x kg(-1) x min(-1) and a caudal epidural block. Transcranial Doppler sonography was used to measure Vmca at five-minute intervals. In half the patients, propofol was substituted with desflurane 1 MAC, 30 min prior to the end of the surgical procedure. Once steady-state had been achieved recordings of Vmca, heart rate, and mean arterial pressure were resumed. Upon termination of the surgical procedure, the maintenance agent was discontinued and recordings continued at one-minute intervals during emergence of anesthesia. There were no demographic differences between the two groups. Vmca increased from 37.2 +/- 3.1 cm x sec(-1) to 57.7 +/- 4.1 cm x sec(-1) when propofol was changed to desflurane (P < 0.01). Upon emergence of anesthesia, Vmca decreased from 57.8 +/- 4.2 cm x sec(-1) to 37.8 +/- 3.2 cm x sec(-1) in the desflurane group (P < 0.01) but remained unchanged in the propofol group. Desflurane is associated with an increase in cerebral blood flow velocity when used to facilitate rapid emergence following a propofol infusion in children. This may be of clinical significance in patients with intracranial pathology.

Use of propofol infusion in Australian and New Zealand paediatric intensive care units.

Despite the risk of propofol infusion syndrome, a rare but often fatal complication of propofol infusion in ventilated children and possibly adults, propofol infusion remains in use in paediatric intensive care units (PICU). This questionnaire study surveys the current pattern of use of this sedative infusion in Australian and New Zealand PICUs. Thirty-three of the 45 paediatric intensive care physicians surveyed (73%), from 12 of the 13 intensive care units, returned completed questionnaires. The majority of practitioners (82%) use propofol infusion in children in PICU, the main indication being for short-term sedation in children requiring procedures. 39% of respondents consider propofol infusion useful in ventilated children requiring longer-term sedation. 67% of paediatric intensivists use maximum infusion doses that may be considered dangerously high (> or = 10 mg/kg/h). Nineteen per cent use propofol infusion for prolonged periods (> 72 hours). A smaller proportion (15%) of respondents indicate that they may use both higher doses and prolonged periods of infusion, a practice likely to lead to a greater chance of serious adverse events. Knowledge of local protocols for the use of propofol infusion is associated with a significantly greater level of monitoring for possible adverse events. We suggest that national guidelines for the use of propofol infusion in children should be developed. These should include clear indications and contraindications to its use, a maximum dose rate and maximum period of infusion, with a ceiling placed on the cumulative dose given and clearly stated minimum monitoring requirements.

Pharmacological management of convulsive status epilepticus in children

Pharmacological management of convulsive status epilepticus in children

Propofol infusion in children: Author's reply

Propofol infusion in children: Author's reply