A clinical audit to assess the efficacy of the Coolsense® Pain Numbing Applicator for intravenous cannulation in children.

The Coolsense® device is a topical applicator that is used to anaesthetise the skin before a painful procedure. It is a handheld device with a temperature-controlled head that acts on application, without chemicals, to cool and anaesthetise the site of injection. This prospective observational audit of 100 children and adolescents aged six to 18 years studied the analgesic efficacy and patient and carer satisfaction rating of the device during intravenous cannulation and complications arising from its use. The audit demonstrated effective skin analgesia for intravenous cannulation in children and adolescents. Ninety-four percent of patients rated the pain during cannulation as less than or equal to three on a numerical pain rating scale of zero to ten. Patient and carer satisfaction with the device and cannulation success rates were high; 66% of patients and 82% of carers 'really liked' the device and 28% of patients and 12% of carers 'liked' it. Ninety-five percent of patients were cannulated on the first attempt. The incidence of complications using the device was low. The Coolsense device appears to be a useful tool that provides effective analgesia for intravenous cannulation in children with minimal complications. Comparative studies with topical local anaesthesia creams are warranted.

Accuracy of dispersing tramadol capsules for oral administration in young children.

Tramadol is used in children aged <12 years for analgesia, particularly for those at risk of obstructive sleep apnoea undergoing adenotonsillectomy. The Australian Therapeutic Goods Administration have strongly recommended that oral tramadol drops (100 mg/ml) not be used in children <12 years because of the risk of inadvertent overdose. The total mass of drug in a 10 ml bottle is 1000 mg. The only alternative preparation available is a 50 mg capsule that requires dispersion of a capsule's contents should smaller doses be required. The accuracy of this preparation has not been assessed. Twenty surgical ward nurses were asked to prepare a 15 mg dose of tramadol from a 50 mg capsule. The dose was within ±5% of 15 mg in 13 cases (65%) and within ±10% in 19 cases (95%) (range 13.9-17.1 mg). Despite the dose variability of this method of preparing tramadol, we consider it sufficiently accurate for clinical use. We also consider it safe, as even at the highest dose prepared, the variability would be unlikely to contribute to clinically significant side-effects or toxicity. Moreover, the maximal dose that could be administered is limited to the size of the capsule (50 mg).

Suspected opioid-induced hyperalgesia in an infant.

One explanation for diminished opioid analgesic efficacy is opioid-induced hyperalgesia (OIH). We report a case of OIH in an infant with gastroschisis, requiring multiple surgical interventions and prolonged sedation for ventilation. This is the first report of OIH in an infant. On day 41 of life after nine separate surgical interventions, the patient's pain scores increased and remained elevated, despite increasing opioid administration. The patient also developed hyperalgesia, allodynia, and photophobia and became extremely irritable upon handling. Other possible causes were excluded, including interruption to opioid delivery, sepsis, acid-base and electrolyte disturbance, and ongoing surgical pathology. An opioid rotation to hydromorphone was initiated and ketamine was commenced. Sedation for ventilation was achieved with dexmedetomidine and midazolam infusions. Over a period of 24 h after opioid de-escalation, pain scores reduced rapidly and the patient became significantly less irritable with handling. All infusions were gradually weaned and eventually ceased.

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.

Postoperative sleep disturbance in pediatric patients using patient-controlled devices (PCA).

BACKGROUND: Sleep disturbance has not been well quantified in pediatric postoperative management, yet has broad implications in pain management as well as upon the physical and psychological well-being of the young patient admitted for surgery. We aimed to describe sleep disturbance in this population using patient-controlled analgesia (PCA) and then identify the predictors of disturbed sleep. METHODS: A retrospective audit and analysis of sleep disturbance in postoperative pediatric patients using PCA devices were performed in a postoperative surgical ward population of a major tertiary referral center. PCA presses were used as a proxy measure of sleep. The description of the sleep disturbance included an unadjusted and adjusted analysis of the proposed predictors of sleep disturbance: age, sex, nature of presentation, operation type, PCA opioid type, presence of background infusion, postoperative night number, and adjuvant medication. All data were entered into an access database developed for the audit and analyzed using stata 8.0. RESULTS: The first 126 children prescribed PCA devices in the year 2004 were audited. One-third of patients in the population prescribed PCA experienced sleep disturbance. Observed predictors of sleep disturbance include older children (OR: 0.86, P=0.001) and those receiving a background infusion (OR: 0.19, P=0.002). Other predictors were not significant. CONCLUSIONS: Sleep disruption is common in children-prescribed PCA opioid analgesia. Older children and those receiving a background infusion were observed to experience less sleep. Other proposed predictors were not found to be reliable. Further investigation into the predictors of disturbed sleep in the postoperative patient is warranted.

Pharmacokinetics of levobupivacaine after caudal epidural administration in infants less than 3 months of age.

BACKGROUND: There are few data describing levobupivacaine pharmacokinetics in infants (<3 months) after caudal administration. METHODS: An open-label study was undertaken to examine the pharmacokinetics of levobupivacaine 2.5 mg ml(-1), 2 mg kg(-1) in children aged less than 3 months after single-shot caudal epidural administration. Plasma concentrations were determined at intervals from 0.5 to 4 h after injection. A population pharmacokinetic analysis of levobupivacaine time-concentration profiles (84 observations) from 22 infants with mean postnatal age (PNA) 2.0 (range 0.6-2.9) months was undertaken using non-linear mixed effects models (NONMEM). Time-concentration profiles were analysed using a one-compartment model with first-order input and first-order elimination. Estimates were standardized to a 70 kg adult using allometric size models. RESULTS: Population parameter estimates (between-subject variability) for total levobupivacaine were clearance (CLt) 12.8 [coefficient of variation (CV) 50.6%] litre h(-1) 70 kg(-1), volume of distribution (Vt) 202 (CV 31.6%) litre 70 kg(-1), absorption half-life (Tabs) 0.323 (CV 18.6%) h 70 kg(-1). Estimates for the unbound drug were clearance (CLfree) 104 (CV 43.5%) litre h(-1) 70 kg(-1), volume of distribution (Vfree) 1700 (CV 44.9%) litre 70 kg(-1), absorption half-life (Tabsfree) 0.175 (CV 83.7%) h 70 kg(-1). There was no effect attributable to PNA on CL or V. Time to peak plasma concentration (Tmax) was 0.82 (CV 18%) h. Peak plasma concentration (Cmax) was 0.69 (CV 25%) microg ml(-1) for total levobupivacaine and 0.09 (CV 37%) microg ml(-1) for unbound levobupivacaine. CONCLUSIONS: Clearance in infants is approximately half that described in adults, suggesting immaturity of P450 CYP3A4 and CYP1A2 enzyme isoforms that metabolize levobupivacaine in infants. This lower clearance delays Tmax, which was noted to occur approximately 50 min after administration of caudal epidural levobupivacaine.

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.

General anaesthesia or conscious sedation for painful procedures in childhood cancer: the family's perspective.

BACKGROUND: Until recently, midazolam sedation was routinely used in our institution for bone marrow aspirates and lumbar punctures in children with cancer. It has been perceived by many doctors and nurses as being well tolerated by children and their families. AIM: To compare the efficacy of inhalational general anaesthesia and midazolam sedation for these procedures. METHODS: A total of 96 children with neoplastic disorders, who received either inhalational general anaesthesia with sevoflurane, nitrous oxide, and oxygen (GA) or sedation with oral or nasal midazolam (SED) as part of their routine preparation for procedures were studied. The experiences of these children were examined during their current procedure and during their first ever procedure. Main outcome measures were the degree of physical restraint used on the child, and the levels of distress and pain experienced by the child during the current procedure and during the first procedure. The family's preference for future procedures was also determined. RESULTS: During 102 procedures under GA, restraint was needed on four occasions (4%) when the anaesthetic mask was first applied, minimal pain was reported, and children were reported as distressed about 25% of the time. During 80 SED procedures, restraint was required in 94%, firm restraint was required in 66%, the child could not be restrained in 14%, median pain score was 6 (scale 0 (no pain) to 6 (maximum pain)), and 90% of the parents reported distress in their child. Ninety per cent of families wanted GA for future procedures. Many families reported dissatisfaction with the sedation regime and raised concerns about the restraint used on their child. CONCLUSIONS: This general anaesthetic regime minimised the need for restraint and was associated with low levels of pain and distress. The sedation regime, by contrast, was much less effective. There was a significant disparity between the perceptions of health professionals and those of families with respect to how children coped with painful procedures.

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

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. METHODS: This was an open study designed to assess the efficacy and safety of 0.25% levobupivacaine administered as a caudal injection at a dose of 2 mg.kg(-1) to 49 paediatric patients aged less than 2 years old undergoing circumcision (group 1), or hernia repair or orchidopexy (group 2). RESULTS: Adequate analgesia (an increase of <20% in pulse or respiratory rate compared with baseline and an absence of gross movement on application of surgical stimulus) was achieved in 43/48 patients evaluable for efficacy (89.6%). All 22 patients in the circumcision group had adequate analgesia, and two of these patients did not require additional analgesia. The mean time to the use of additional analgesia was 7.3 h. Only one event (a mild rash) was considered possibly related to study medication. CONCLUSIONS: Levobupivacaine is a promising new local anaesthetic agent for pain management in paediatric patients and appears to offer similar anaesthetic efficacy to racemic bupivacaine with a potentially improved tolerability profile.

Sedation practices for Australian and New Zealand paediatric oncology patients.

OBJECTIVES: Paediatric oncology patients often require repeated bone marrow aspirates and lumbar punctures. These procedures commonly require sedation and analgesia. The Australian and New Zealand College of Anaesthetists and the American Academy of Pediatrics have published guidelines that provide recommendations on monitoring and staffing requirements during sedation of paediatric patients. A survey was conducted of the oncology units in Australia and New Zealand in order to compare current practices with published guidelines. METHODS: Telephone interviews were conducted with nursing or medical staff members. RESULTS: Fourteen oncology units collectively perform approximately 130 procedures each week, of which 74% are performed under general anaesthesia. Of the remainder, most are performed using conscious sedation. Most units adhere to published recommendations regarding equipment and staffing during procedures performed under sedation. Only a minority of units follow guidelines regarding documentation; fasting requirements; observation and documentation of vital signs during and after the procedure; and obtaining informed consent for procedures performed using sedation. CONCLUSION: Sedation practices among paediatric oncology units in Australia and New Zealand vary. None of the units fully adhere to published guidelines on childhood sedation. Paediatric oncology units should be familiar with the content of these guidelines and make an informed decision as to their usefulness, both in directing best clinical practice, and in supporting current practice in the event of medico-legal challenge.

Management of chronic pain in children.

OBJECTIVES: To describe the demography, clinical characteristics, treatment, functional limitations and outcomes of patients referred to a paediatric multidisciplinary pain clinic. DESIGN: Prospective data collection, descriptive study. PATIENTS AND SETTING: Tertiary referral centre pain clinic (Royal Children's Hospital, Melbourne) over two years (March 1998 - March 2000). MAIN OUTCOME MEASURES: Pain profile; functional disability (school absenteeism, sleep disturbance and inability to perform sport); treatments received; outcome. RESULTS: 207 patients (mean age, 13.1 years; 73% females; 29% rural residents) were referred in the two years. Concomitant medical conditions were present in 106/207 (51%) patients, the commonest being cerebral palsy or spasticity (22 patients) and malignancy (18). Complex regional pain syndrome was diagnosed in 44 patients. Functional disability due to pain included school absenteeism (95% of school attenders), sleep disruption (71% of all patients) and inability to perform sport (90% of those able to participate in sport previously). Of the 105 patients who missed five or more days of school because of pain, 93 attended school regularly after treatment. Sleep disturbance improved in 129/146 (88%) patients, and 129/147 (88%) resumed sporting activity after multidisciplinary intervention. Outcome was classified as good in 134 patients (65%), moderate in 32 (15%) and poor in 16 (8%). CONCLUSIONS: Chronic pain in children and adolescents often results in considerable functional disability. Functional improvement can be achieved using a multidisciplinary approach to pain management in children.

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.

Unintentional paediatric subdural catheter with oculomotor and abducens nerve palsies.

A 13-year-old female with a past history of lumbar laminectomy developed a subdural block 18 h after the commencement of an epidural infusion of bupivacaine 0.125% and fentanyl 2 micrograms.ml-1. Signs at presentation included bilateral abducens nerve palsies in the absence of headache and a previously unreported unilateral third cranial nerve palsy. An epidurogram displayed subdural placement.

Depth of central venous catheter insertion in adults: an audit and assessment of a technique to improve tip position.

A technique of subclavian vein catheterization is described, tailored to the individual patient, to reduce the risk of right atrial placement with central venous catheter (CVC) insertion. Using data gathered retrospectively for Quality Improvement purposes, CVC tip location was assessed. The standard technique used in our cardiac anaesthesia unit at that time was to insert all CVCs to a depth of 15 cm from the skin. We then compared CVC tip location using a new "tailored" technique. The tailored method involved measuring the distance from the skin at which venepuncture occurred and using this distance to determine depth of CVC insertion. Using the tailored technique significantly decreases the frequency with which CVC tips enter the right atrium (P < 0.001). An advantage of the tailored technique is that the distance between the most proximal and the distal ports of multi-lumen CVCs is taken into consideration, reducing the risk of extravasation via the proximal port.

The effect of aprotinin on thrombelastography in vitro.

The effect of low dose (50 KIU/ml) and high dose (200 KIU/ml) aprotinin on standard thrombelastographic variables (r, K, alpha, MA) was examined in vitro using blood from forty ASA Class 1 patients. Both concentrations of aprotinin resulted in minor increases in r time above the normal range (P < 0.05). Aprotinin did not alter other thrombelastographic variables. The results indicate that aprotinin is a mild direct anticoagulant in vitro as assessed by thrombelastography.

Patient-controlled analgesia: a comparison with nurse-controlled intravenous opioid infusions.

Patient-controlled analgesia (PCA) with intravenous pethidine was compared with nurse-controlled pethidine infusions for pain relief in 200 patients after major abdominal or thoracic surgery. Pain, level of sedation, nausea and presence of other adverse effects, in addition to cumulative pethidine requirement, were measured for the first 24 hours after surgery. Both groups were similar for age, weight and type of surgery. There was no significant difference between the quality of analgesia achieved in both groups. The frequency and severity of adverse effects was also similar. The cumulative pethidine dose administered to both groups was identical. It is concluded that nurse-controlled opioid infusions are as effective as PCA and may be used as an alternative to PCA where this is either unavailable or unsuitable.

Comparison of preoperative with postoperative lignocaine infiltration on postoperative analgesic requirements.

Ninety patients undergoing appendicectomy were allocated randomly to receive 1.5% lignocaine 15 ml with adrenaline infiltrated into the proposed wound line 3 min before incision, lignocaine 15 ml with adrenaline infiltrated into the wound on closure or no wound infiltration. After operation, all patients received pethidine by patient-controlled analgesia. Pain scores were assessed while supine and sitting on day 1 and 2 and the cumulative pethidine dose administered was recorded at 12, 24, 36 and 48 h after operation. There were no significant differences in the cumulative dose of pethidine required or pain scores between the three groups at any time point after operation. We conclude that pre-incisional infiltration with 1.5% lignocaine had no advantage compared with infiltration at wound closure or no wound infiltration in reducing postoperative analgesic requirements or pain scores after appendicectomy.

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

An 8-year-old boy known to have Duchenne's 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 start 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.