Continuous remifentanil for pediatric neurosurgery patients

Analgosedation in paediatric severe traumatic brain injury (TBI): practice, pitfalls and possibilities

Analgosedation is a fundamental part of traumatic brain injury (TBI) treatment guidelines, encompassing both first and second tier supportive strategies. Worldwide analgosedation practices continue to be heterogeneous due to the low level of evidence in treatment guidelines (level III) and the choice of analgosedative drugs is made by the treating clinician. Current practice is thus empirical and may result in unfavourable (often hemodynamic) side effects. This article presents an overview of current analgosedation practices in the paediatric intensive care unit (PICU) and addresses pitfalls both in the short and long term. We discuss innovative (pre-)clinical research that can provide the framework for initiatives to improve our pharmacological understanding of analgesic and sedative drugs used in paediatric severe TBI and ultimately facilitate steps towards evidence-based and precision pharmacotherapy in this vulnerable patient group.

Efficacy of sedation regimens to facilitate mechanical ventilation in the pediatric intensive care unit: a systematic review

OBJECTIVE

Children admitted to pediatric intensive care units (PICUs) often receive sedatives to facilitate mechanical ventilation. However, despite their widespread use, data supporting appropriate dosing, safety, and optimal regimens for sedation during mechanical ventilation are lacking. Therefore, we conducted a systematic review of published data regarding efficacy of sedation to facilitate mechanical ventilation in PICU patients. Our primary objective was to identify and evaluate the quality of evidence supporting sedatives used in PICUs for this purpose.

DATA SOURCES

We searched MEDLINE, EMBASE, and The Cochrane Registry of Clinical Trials from 1966 to June 2008 to identify published articles evaluating sedation regimens to facilitate mechanical ventilation in PICU patients.

STUDY SELECTION

We included only those studies of intubated PICU or pediatric cardiac intensive care unit patients receiving pharmacologic agents to facilitate mechanical ventilation that reported quality of sedation as an outcome.

DATA EXTRACTION

We analyzed studies separately for study type and by agents being studied. Studies were appraised using criteria of particular importance for reviews evaluating sedatives.

DATA SYNTHESIS

Our search strategy yielded 39 studies, including 3 randomized trials, 15 cohort studies, and 21 cases series or reports. The 39 studies evaluated a total of 39 different sedation regimens, with 21 different scoring systems, in a total of 901 PICU/cardiac intensive care unit patients ranging in age from 3 days to 19 years old. Most of the studies were small (<30 patients), and only four studies compared one or more agents to another. Few studies thoroughly evaluated drug safety, and only one study met all quality criteria.

CONCLUSIONS

Despite the widespread use of sedatives to facilitate mechanical ventilation in the PICU, we found that high-quality evidence to guide clinical practice is still limited. Pediatric randomized, controlled trials with reproducible methods and assessment of drug safety are needed.

Remifentanil and the brain

BACKGROUND AND AIM

Remifentanil is an ultra-short-acting opioid, increasingly used today in neuroanesthesia and neurointensive care. Its characteristics make remifentanil a potentially ideal agent, but previous data have cast a shadow on this opioid, supporting potentially toxic effects on the ischemic brain. The aim of the present concise review is to survey available up-to-date information on the effects of remifentanil on the central nervous system.

METHOD

A MEDLINE search within the past seven years for available up-to-date information on remifentanil and brain was performed.

RESULTS

Concise up-to-date information on the effects of remifentanil on the central nervous system was reported, with a particular emphasis on the following topics: cerebral metabolism, electroencephalogram, electrocorticography, motor-evoked potentials, regional cerebral blood flow, cerebral blood flow velocity, arterial hypotension and hypertension, intracranial pressure, cerebral perfusion pressure, cerebral autoregulation, cerebrovascular CO(2) reactivity, cerebrospinal fluid, painful stimulation, analgesia and hyperalgesia, neuroprotection, neurotoxicity and hypothermia.

CONCLUSION

The knowledge of the influence of remifentanil on brain functions is crucial before routine use in neuroanesthesia to improve anesthesia performance and patient safety as well as outcome.

Experience with remifentanil in neonates and infants

Remifentanil is a relatively new synthetic opioid, which is not licensed worldwide for neonates and infants. Because of its unique pharmacokinetic properties with a short recovery profile, it could be the ideal opioid for neonates and infants, who are especially sensitive to respiratory depression by opioids. Therefore, we conducted a MEDLINE search on all articles dealing with the use of remifentanil in this important subgroup of patients. Most experience with remifentanil in neonates and infants is as maintenance anaesthesia during surgery. In approximately 300 neonates and infants, remifentanil proved to be an effective and safely used opioid for this indication. However, very limited data exist on remifentanil for analgesia and sedation of mechanically ventilated paediatric intensive care patients. Further research with remifentanil in neonates and infants should focus on this group of patients because remifentanil, with its very short context-sensitive half-life, could result in shorter extubation times compared with commonly used opioids such as morphine or fentanyl.

Anesthesia for epilepsy surgery in children

BACKGROUND

The perioperative management of infants and children for epilepsy surgery should focus on the specific problems unique to the state of the disease, age of the child, and operative conditions. A basic understanding of age-dependent variables and the interaction of anesthetic and surgical procedures are essential in minimizing perioperative morbidity and mortality. Specific medical conditions that impact the conduct of anesthesia include congenital anomalies, chronic anticonvulsant therapies, and evolving coagulopathies. The neurosurgical procedure and neurophysiological monitoring will determine the type of anesthetic technique to be utilized during surgery.

OBJECTIVE

This review will provide a systematic approach to pediatric patients undergoing epilepsy surgery.

Sevoflurane-remifentanil vs isoflurane-remifentanil for the surgical correction of craniosynostosis in infants

BACKGROUND

The aim of the present study was to compare the efficacy of isoflurane-remifentanil and sevoflurane-remifentanil combinations during neurosurgical correction craniosynostosis.

METHODS

Twenty-two infants with craniosynostosis received a slow bolus of remifentanil followed by continuous infusion. The infants were randomly divided into two groups: remifentanil followed by sevoflurane (the 'sevoflurane group'), and remifentanil followed by isoflurane (the 'isoflurane group'). We monitored electrocardiogram (ECG), heart rate (HR), invasive arterial blood pressure (IABP), pulse oximetry saturation (SpO(2)), endtidal CO(2) (P(ECO(2))), inspired fraction of oxygen (FiO(2)) and endtidal volatile agent (PE volatile agent) at 12 time points, from the beginning of surgery (T0) until the cessation of drugs (T11). The volatile agent was stopped prior to skin suture and the remifentanil infusion after skin closure. Subsequently, we evaluated recovery time of spontaneous breathing and spontaneous eye opening and time of extubation at 5, 10, and 15 min after extubation, the Steward Recovery Score (SRS) was assessed. Patients were then transferred to the Pediatric Intensive Care Unit (PICU).

RESULTS

During the surgical procedure the hemodynamic parameters between the two groups did not show statistically significant differences. There were also no significant differences in terms of awakening time or SRS.

CONCLUSIONS

The rapid recovery of the children (confirmed by their high values of SRS) makes it possible to reliably assess the patient's neurological condition immediately after surgery.

[Anesthetic management of pediatric cleft lip and cleft palate repair]

We have developed a modern strategy for the anesthetic management of pediatric cleft lip and cleft palate repair using anesthetic drugs such as sevoflurane, desflurane, acetaminophen, remifentanil, and pirtitramide together with new techniques. It provides best conditions for the surgeon and maximum safety for the pediatric patient. A team of pediatricians, neonatologists, pediatric surgeons, and pediatric anesthetists have tackled the problem of management of children with craniofacial abnormalities such as cleft lip and cleft palate. The best and safest anesthetic techniques are outlined and the most frequent complications are discussed, e.g. management of the difficult airway, the airway in patients with complex craniofacial abnormalities, fiberoptic endotracheal intubation through a laryngeal mask, intraoperative dislocation of the endotracheal tube, postoperative airway obstruction and perioperative bleeding.

The pharmacological treatment of neonatal pain

Optimal analgesia remains a major challenge for all involved in the care of (critically) ill newborns. The rapid changes in liver metabolism involving maturation of liver enzymes and renal clearance of drugs render (extreme) very low birth weight infants different from newborns of later postconceptional age with regards to the use of opioids such as morphine and fentanyl. Acute and/or procedural pain has been investigated fairly recently in randomized controlled trials and there are now guidelines. The long-term effects of opioid use in this particular age group of vulnerable babies await further evaluation.

The Use of Ultra-Short-Acting Opioids in Paediatric Anaesthesia

Remifentanil is a synthetic opioid that was developed in the early 1990s and introduced into clinical use in 1996. It is a methyl ester and is metabolised by nonspecific tissue and plasma esterases. Consequently, it is a drug that undergoes rapid elimination and has a reported terminal elimination half-life of between 10 and 35 minutes. Because there is no drug accumulation, the context-sensitive half-time remains constant; thus the pharmacokinetics of the drug do not change regardless of the duration of infusion. The organ-independent elimination of remifentanil, coupled with the fact that its clearance is greater in infants and neonates compared with older age groups, make its pharmacokinetic profile different from any other opioid. In addition, its unique metabolism confers predictability in its clinical use. Like other opioid mu receptor agonists, remifentanil provides dose-dependent analgesia, while the adverse effects of this drug, e.g. respiratory depression, are also thought to be dose related. The incidence of nausea and vomiting appear similar to other opioids. Its rapid and consistent metabolism regardless of duration of infusion has made remifentanil an attractive analgesic/anaesthetic option for paediatric care providers.

Remifentanil infusion for cleft palate surgery in young infants

BACKGROUND

The residual depressant effect of opioid is a major concern in infants scheduled for cleft palate repair. Remifentanil is associated with a fast and predictable recovery, independent of age.

METHODS

About 40 infants in the 2-12 month age range were prospectively enrolled in this open study, to receive either remifentanil (infusion starting at 0.25 microg x kg(-1) x min(-1)) or sufentanil as part of a balanced anaesthesia regimen. Isoflurane was maintained at an endtidal concentration of 1.2% in oxygen and nitrous oxide and the opioid dosing was titrated to autonomic responses. Postoperative pain relief was provided by morphine infusion. Morphine administration started intraoperatively in the remifentanil group.

RESULTS

Consistent haemodynamic stability was achieved throughout surgery in both groups. Infants of the remifentanil group required, on average, lower concentrations of isoflurane than children of the sufentanil group (1.2 +/- 0.2% vs 1.7 +/- 0.3%, P < 0.001). The median time from last suture to tracheal extubation was 12.5 min (5-25 min) in the remifentanil group and 15.0 min (10-30 min) in the sufentanil group. There was no evidence of hyperalgesia or enhanced morphine consumption in the remifentanil group compared with the sufentanil group. Postoperative pain scores were even lower in the remifentanil group, compared with the sufentanil group, soon after arrival in the postanaesthesia care unit.

CONCLUSIONS

Remifentanil-based anaesthesia appeared well suited for primary cleft palate repair in young infants.