George A. Chalkiadis

Anaesthesia and pain management in cerebral palsy

Cerebral palsy is the result of an injury to the developing brain during the antenatal, perinatal or postnatal period. Clinical manifestations relate to the area affected. Some of the conditions associated with cerebral palsy require surgical intervention. Problems during the peri‐operative period may include hypothermia, nausea and vomiting and muscle spasm. Peri‐operative seizure control, respiratory function and gastro‐oesophageal reflux also require consideration. Intellectual disability is common and, in those affected, may range from mild to severe. These children should be handled with sensitivity as communication disorders and sensory deficits may mask mild or normal intellect. They should be accompanied by their carers at induction and in the recovery room as they usually know how best to communicate with them. Postoperative pain management and the prevention of muscle spasm is important and some of the drugs used in the management of spasm such as baclofen and botulinum toxin are discussed. Epidural analgesia is particularly valuable when major orthopaedic procedures are performed.

The severity and duration of postoperative pain and analgesia requirements in children after tonsillectomy, orchidopexy, or inguinal hernia repair

Objectives:  To provide parents of children with accurate information regarding postoperative pain, its management, and functioning following common surgical procedures.

I.V. acetaminophen pharmacokinetics in neonates after multiple doses

BACKGROUND Pharmacokinetics of an i.v. prodrug of acetaminophen (propacetamol) in neonates after repeat dosing are reported, with scant data for i.v. acetaminophen formulation. METHODS Neonates from an intensive care unit received 6-hourly prn i.v. acetaminophen dosed according to postmenstrual age (PMA): 28-32 weeks, 10 mg kg(-1); 32-36 weeks, 12.5 mg kg(-1); and > or =36 weeks, 15 mg kg(-1). A maximum of five blood samples for assay and liver function tests (LFTs) were collected. A one-compartment linear disposition model (zero-order input; first-order elimination) was used to describe time-concentration profiles using population modelling (NONMEM). RESULTS Fifty neonates, median (range) PMA 38.6 (32-45) weeks, mean (SD) weight 2.9 (0.7) kg, received a mean of 15 doses over a median 4 days with 189 serum acetaminophen and 231 LFT measurements. Standardized population parameter estimates for a term neonate were clearance (CL) 5.24 (CV 30.5%) litre h(-1) 70 kg(-1) and volume of distribution (V) 76 (29.6%) litre 70 kg(-1). CL increased with PMA from 4.4 litre h(-1) 70 kg(-1) at 34 weeks to 6.3 litre h(-1) 70 kg(-1) at 46 weeks. The presence of unconjugated hyperbilirubinaemia was associated with reduced CL: 150 micromol litre(-1) associated with 40% CL reduction. Acetaminophen concentrations between 10 and 23 mg litre(-1) at steady state are predicted after 15 mg kg(-1) 6-hourly for a neonate of PMA 40 weeks. Hepatic enzyme analysis of daily samples changed significantly for one patient whose alanine aminotransferase concentration tripled. CONCLUSIONS The parameter estimates are similar to those described for propacetamol. There was no evidence of hepatotoxicity. Unconjugated hyperbilirubinaemia impacts upon CL, dictating dose reduction.

Effective postoperative pain management in children after ambulatory surgery, with a focus on tonsillectomy: barriers and possible solutions

Pain following ambulatory surgery is often poorly managed at home. Certain procedures, such as tonsillectomy, cause high levels of pain for at least 1 week postoperatively. This impacts significantly on recovery and postoperative morbidity with regards to oral intake, sleep, and behavior. Barriers to effective postoperative pain management at home following discharge have been investigated and incorporate: parental factors, such as the ability to recognize and assess their childs pain, and misconceptions about analgesics; child factors, such as refusal to take medication; medication factors, such as ineffective medication or inadequate formulation or dose of analgesics; and system factors, such as poor discharge instructions, difficulty in obtaining medication and lack of information provision. A number of interventions have been suggested and trialled in an effort to address these barriers, which encompass educational strategies, improved information provision, improved medication regimens, and the provision of tools to aid parents in the pain management of their children. All in all, improvements in pain outcomes have been minor, and a more holistic approach, that appreciates the complex and multifaceted nature of pain management at home, is required.

Cardiac arrest after isoflurane anaesthesia in a patient with Duchenne's muscular dystrophy

An 8‐year‐old boy known to have Duchennes muscular dystrophy suffered a cardiac arrest 10 minutes after he regained consciousness after isoflurane anaesthesia for an orchidopexy procedure. Resuscitation was successful 2 hours after the star of external cardiac compression and after correction of hyperkalaemia and the administration of dantrolene. He later developed myoglobinuria, elevated creatine kinase and a metabolic and respiratory acidosis. He demonstrated a delayed increase in rectal temperature.

Efficacy and safety of caudal injection of levobupivacaine, 0.25%, in children under 2 years of age undergoing inguinal hernia repair, circumcision or orchidopexy

Summary Background: Levobupivacaine is the S(–)‐enantiomer of racemic bupivacaine. Evidence suggests that it is less cardiotoxic than racemic bupivacaine and the R(+)‐enantiomer, dexbupivacaine, while retaining similar local anaesthetic properties and potency to racemic bupivacaine.

Does epidural analgesia delay the diagnosis of lower limb compartment syndrome in children

One of the cardinal symptoms of compartment syndrome is pain. A literature review was undertaken in order to assess the association of epidural analgesia and compartment syndrome in children, whether epidural analgesia delays the diagnosis, and to identify patients who might be at risk. Evidence was sought to offer recommendations in the use of epidural analgesia in patients at risk of developing compartment syndrome of the lower limb. Increasing analgesic use, increasing/breakthrough pain and pain remote to the surgical site were identified as important early warning signs of impending compartment syndrome in the lower limb of a child with a working epidural. The presence of any should trigger immediate examination of the painful site, and active management of the situation (we have proposed one clinical pathway). Avoidance of dense sensory or motor block and unnecessary sensory blockade of areas remote to the surgical site allows full assessment of the child and may prevent any delay in diagnosis of compartment syndrome. Focusing on excluding the diagnosis of compartment syndrome rather than failure of analgesic modality is vital. In the pediatric cases reviewed there was no clear evidence that the presence of an epidural had delayed the diagnosis.

Age and size are the major covariates for prediction of levobupivacaine clearance in children

Background : We aimed to identify and quantify major factors describing the variability of levobupivacaine clearance in children.

Pharmacokinetics of levobupivacaine 0.25% following caudal administration in children under 2 years of age†

BACKGROUND Levobupivacaine, the S(-)enantiomer of racemic bupivacaine is less cardiotoxic than racemic bupivacaine and the R(+)enantiomer dexbupivacaine, while retaining similar local anaesthetic properties and potency to racemic bupivacaine. The pharmacokinetic profiles of the two bupivacaine enantiomers differs and that of racemic bupivacaine may be age dependent. We examined the pharmacokinetics of levobupivacaine after its single shot caudal epidural administration in children. METHODS An open-label phase 2 study was undertaken to examine the pharmacokinetics of levobupivacaine 0.25% 2 mg kg(-1) in 49 children aged less than 2 yr, after single shot caudal epidural administration. Plasma concentrations were determined at intervals up to 60 min after caudal injection. RESULTS Time to peak plasma concentration (T(max)) ranged between 5 and 60 min (median 30 min) and was reached later in children aged less than 3 months (P<0.005). Peak plasma concentration (C(max)) ranged between 0.41 and 2.12 micro g ml(-1) (median 0.80, mean (SD) 0.91 (0.40) micro g ml(-1)). CONCLUSION After the caudal epidural administration of levobupivacaine 2 mg kg(-1) in children less than 2 yr of age, C(max) was within the accepted safe range for racemic bupivacaine. T(max) varied and occurred later in some children, particularly those aged less than 3 months. Sampling in future pharmacokinetic studies in this age group should extend beyond 60 min.

Achieving organizational change in pediatric pain management

BACKGROUND Pain in hospitalized children is often undertreated. Little information exists to guide the process of organizational change with a view to improving pain management practices. OBJECTIVES To describe the process and results of a hospital-wide review of pain management practices designed to identify deficiencies in service provision and recommend directions for change in a pediatric hospital. DESIGN Prospective consultation of the clinical staff of a specialist pediatric hospital, using qualitative research methodology involving semistructured individual and group interviews. Recommendations based on the interview findings were made by a hospital-appointed working party. RESULTS A total of 454 staff (27% of all clinical staff) from a variety of professional backgrounds, representing almost every hospital unit or department, were interviewed. Procedural and persistent (chronic) pain was identified as the area needing the most improvement. Barriers to improving pain management included variability in practice, outmoded beliefs and inadequate knowledge, factors which were seen to contribute to a culture of slow or no change. Recommendations of the working party and changes achieved after the review are described. CONCLUSION The review process identified deficiencies in the management of pain in children, and barriers to its effective management. With institutional support, the present review has guided improvement.