Notes: Background: The aim was to investigate the efficacy, tolerance and pharmacokinetics of ropivavcaine when administered for ilioinguinal/iliohypogastric block in children. Methods: We examined the pharmacokinetics and analgesic efficacy after ilioinguinal/iliohypogastric nerve block with 3 mg·kg−1 ropivacaine 5 mg·ml−1 in 22 children, aged 1–12 years, who were scheduled for inguinal surgery. Sixteen of 22 patients had a postoperative pain score 〈 4 (Objective Pain Scale). Nine children were given supplementary analgesics during the first six postoperative hours. Results: The peak plasma concentration of total ropivacaine was 1.50 ± 0.93 mg·l−1 (mean ± SD) (range 0.64–4.77 mg·l−1) 15–64 min after the injection. The peak plasma concentration of free ropivacaine was 0.05 ± 0.03 mg·l−1 (0.02–0.14 mg·l−1), which is well below the threshold for toxicity in adults. The terminal half-life was 2.0 ± 0.7 h. No safety concerns or symptoms suggestive of systemic toxicity were observed. Conclusions: A dose of 3 mg·kg−1 of ropivacaine given as a single ilioinguinal/iliohypogastric nerve block in 1–12-year-old children provides satisfactory postoperative pain relief, and is well tolerated.

Notes: Introduction:  The primary objective of this noncomparative study was to evaluate the pharmacokinetics of ropivacaine during a 48–72-h continuous epidural infusion of ropivacaine in children under 1 year. The secondary objectives were to assess efficacy and safety.Methods:  Neonates and infants (ASA I–III, gestational age ≥37 weeks, ≥2.5 kg, scheduled for major abdominal or thoracic surgery) were included and separated into age groups: 0–30 (neonate), 31–90, 91–180, and 181–365 days. Ethics committee approval and informed parental consent were obtained before inclusion. An epidural catheter was introduced under general anesthesia at the appropriate dermatomal level. An initial bolus dose (0.9–2.0 mg·kg−1 of ropivacaine 0.2%) was followed by an epidural infusion (0.2 mg·kg−1·h−1 for infants 〈180 days or 0.4 mg·kg−1·h−1 for infants 〉180 days). Plasma samples were collected every 12 h from 24 h, and on termination of the epidural infusion. Postoperative pain was evaluated using both the Objective Pain Scale and a four-graded descriptive scale.Results:  Forty-five infants, median age 116 (0–362) days, were included. Forty-three and 19 patients received an infusion for at least 48 and 72 h, respectively. Satisfactory analgesia was provided in the majority, only 20 patients were given supplementary medication during the infusion. In all age groups, plasma concentrations of unbound ropivacaine leveled at 24 h, without any further increase at 48 and 72 h. Because of lower clearance of unbound ropivacaine in neonates (mean 33 ml·min−1·kg−1) than in infants above the age of 30 days (80, 124, and 163 ml·min−1·kg−1, respectively, in the age groups 31–90, 91–180, and 180–365 days), unbound ropivacaine concentrations at the end of infusion were higher in neonates [median 0.10 mg·l−1 (0.04–0.21 mg·l−1)] than in infants 〉30 days [median 0.03 mg·l−1 (0.003–0.10 mg·l−1)].Conclusion:  Epidural infusions (0.2–0.4 mg·kg−1·h−1 ropivacaine) provided satisfactory pain relief in neonates and infants under 1 year. As plasma concentrations of unbound ropivacaine were not influenced by the duration of the infusion, ropivacaine can be safely used for postoperative epidural infusion for 48–72 h. Levels of unbound ropivacaine were higher in the neonates than in the infants, but were below threshold concentrations for CNS toxicity in adults (≥0.35 mg·l−1). This should not preclude the use of ropivacaine infusions in neonates but suggests a need for caution during the first weeks of life.

Notes: Limited information is available about the correlation between cerebral temperature and routine temperature measurements during cardiopulmonary bypass in infants. Nasopharyngeal, tympanic membrane and rectal temperatures were compared with jugular bulb temperature in ten infants operated on with moderate or deep hypothermia. The cerebral arteriovenous saturation differences were correlated with the temperatures at the four measurement sites. The jugular bulb and nasopharyngeal temperatures showed the most rapid response during cooling and rewarming. The tympanic temperature response varied in an unpredictable way. Rectal temperature, which was the target for rewarming, lagged behind during both cooling and rewarming. Overwarming at the end of cardiopulmonary bypass, seen as jugular bulb and nasopharyngeal temperatures exceeding 38??C, was common after deep hypothermia. A high correlation was found between the cerebral arteriovenous oxygen saturation differences and the jugular bulb temperature (r=0.81) and the nasopharyngeal and the tympanic temperature (r=0.79), whereas the correlation with rectal temperature was weaker (0.66).

Notes: The aim of this study was to evaluate changes in concentrations of the neurospecific protein S-100 in relation to cardiac surgery with cardiopulmonary bypass (CPB) and noncardiac general surgery in children below 3 years of age. Seventeen children underwent surgery for congenital heart disease and all survived without clinical signs of neurological complications. Samples for plasma concentrations of S-100 in these patients were taken on three occasions in connection with surgery: before the start of surgery, after CPB and finally 16–20 h after CPB. In the noncardiac group of 31 children, S-100 concentrations were measured on two occasions: before surgery and during surgery. In both groups, a significant increase in S-100 concentrations was observed during surgery, although the increase in the CPB group was significantly higher than in the noncardiac group. The CPB group included four children with Down's syndrome who had higher mean S-100 concentrations on all sampling occasions compared to the remaining patients. The peak S-100 concentrations after cardiac surgery were related to the duration of CPB, the time from the termination of CPB to the first post-CPB sample, as well as mean arterial pressure and cerebral arteriovenous lactate difference during rewarming. All the children studied (Down's patients excluded) had age-dependent plasma concentrations of S-100 measured before surgery. It can be concluded that CPB initiates a marked but transient release of S-100 into the systemic circulation during open heart surgery in children who are not developing clinical signs of neurological sequelae.

Notes: This study included 17 young children, who were operated with cardioplumonary bypass for congenital heart defects and were cooled to 20°C or 25°C. No glucose, except for the pump prime solution, was administered during surgery. Samples of arterial blood, cerebral venous blood from the jugular bulb and mixed venous blood from the bypass circuit were obtained and analysed for concentrations of glucose, lactate and ketones as well as oxygen saturation. The prime content of lactate significantly contributed to the arterial lactate concentrations, which together with the cerebral arteriovenous (A-V) lactate differences remained elevated throughout the bypass period. The prime content of glucose had less influence on the arterial concentrations and these did not increase until the rewarming period, when indications of gluconeogenesis from lactate were found. Arterial ketone concentrations also increased during rewarming in parallel with significant cerebral uptake of ketones. The lowest cerebral A-V glucose, lactate and oxygen saturation differences were found at the target minimum temperature and this effect was significantly more pronounced in the patients cooled to 20°C.

Notes: Background : The aims of this study were to evaluate pharmacokinetics, efficacy and safety of ropivacaine in infants aged 0–12 months following a single caudal injection.Methods : Term ASA I–III patients, scheduled for surgery, with a body weight of ≥2500 g received a caudal block with ropivacaine 2 mg·ml−1, 1.0 ml·kg−1. Plasma samples were collected at different time intervals up to 30 h, for analysis of total and unbound ropivacaine and alpha-1-acid glycoprotein (AAG). Pharmacokinetic data were characterized by population analysis. Unbound and total concentrations from 35 patients, median (min–max) postnatal age of 66 (4–351) days, were included in the nonlinear mixed effects modeling to provide estimates of pharmacokinetic parameters and the exploration of covariate relationships. Simulations were made to test the predictive performance of the final model and to describe the effect of significant covariates on systemic exposure.Results : The mean (min–max) peak plasma concentration of total ropivacaine was 0.83 (0.05–1.57) mg·l−1 at 0.5–5.7 h (median: 1.0 h) and the plasma concentration of unbound ropivacaine was 0.042 (0.012–0.081) mg·l−1 within 0.5–1 h. The observed unbound fraction in plasma was 6% (1%–14%). A one-compartment open model with first-order absorption and elimination, incorporating a linear-binding model of ropivacaine to AAG best described the data. The only significant covariate relationship was that of age on Clu/F according to the following relationship Clu/F = 3.01 × e0.00474 × Age. This predicts a Clu/F of 3.5 l·h−1·kg−1 at 30 days and 10.8 l·h−1·kg−1 at 270 days with corresponding terminal half-lives of 6.7 and 2.2 h. The interindividual variability (coefficient of variation, CV) in Clu/F was 39%. The population estimate (CV) of ka was 1.65 h−1 (30%), Vu/F was 33.6 (l·kg−1) (45%) and Ka was 1.78 l·mg−1 (14%). Thirty-five infants received supplementary analgesics (mostly paracetamol). The median time to first supplementary analgesic (based on all 37 patients) was 3.9 h. No safety concerns or signs of systemic toxicity were observed.Conclusions : Following a caudal block with ropivacaine 2 mg·kg−1 plasma concentrations of unbound ropivacaine were well below threshold levels for toxicity in adults. Apparent volume of distribution is unchanged, apparent unbound clearance increases and the terminal half-life decreases with age in 0–12-month-old neonates and infants. The postoperative pain management provided adequate analgesia and was well tolerated.