Nerve Block In Children Research Articles

Pharmacokinetics of 0.75% ropivacaine and 0.5% bupivacaine after ilioinguinal–iliohypogastric nerve block in children

Blockade of the ilioinguinal and iliohypogastric nerves is a useful procedure in paediatric patients undergoing inguinal surgery. Bupivacaine 2 mg kg-1 has been recommended for this block. We compared the plasma concentrations of ropivacaine and bupivacaine following an ilioinguinal-iliohypogastric block. Forty children scheduled for elective inguinal surgery were randomized to receive 2 mg kg-1 of either 0.75% ropivacaine or 0.5% bupivacaine. Surgical anaesthesia was maintained with mask inhalation of oxygen, nitrous oxide and sevoflurane. Venous blood samples were drawn at regular intervals for up to 2 h and plasma was separated. Total venous plasma concentrations were determined by gas chromatography. The groups were similar with respect to age, weight and dose of local anaesthetic. The peak plasma concentration achieved was significantly higher in the bupivacaine group compared with the ropivacaine group (2.2 vs 1.2 micrograms ml-1, P = 0.025). The time to peak plasma concentration was significantly shorter in the bupivacaine group (24 vs 35 min, P = 0.024). The initial distribution half time of bupivacaine was significantly shorter (3.6 vs 6.5 min, P = 0.020) compared with that of ropivacaine. Bupivacaine is more rapidly absorbed from the injection site and leads to higher plasma concentrations than ropivacaine.

Pediatric Regional Anesthesia: Beyond the Caudal

Pediatric Regional Anesthesia: Beyond the Caudal

Local Anesthetic Serum Concentrations After Penile Nerve Block in Children

Sfez, Michel MD; Mapihan, Yann Le MD; Mazoit, Xavier MD; Dreux-Boucard, Hélène MD Author Information

Sciatic Nerve Blocks in Children

Three techniques for blocking the sciatic nerve, differing in approach (posterior in group P; lateral in group L; and anterior in group A), were prospectively evaluated in 180 children who were also given light general anesthesia for surgery below the knee. Four anesthetic solutions with epinephrine (1% lidocaine, 0.5% bupivacaine, and two mixtures of 0.5% bupivacaine with either 1% lidocaine or 1% etidocaine) were administered to 15 patients in each group. The sciatic nerve was located by electrical stimulation or, when muscle twitches were not elicited, using a loss-of-resistance technique. Twitches were "typical" in 154 patients of whom 153 developed sciatic nerve block. In 26 patients twitches were atypical (eight patients) or absent (18 patients) and a sciatic block developed in only 13 patients (50%). The depth to which the needle was inserted was measured in each procedure; it varied according to patient's age and weight and was significantly less with the posterior approach than with either the lateral or anterior routes. The overall success rate exceeded 90% in the three groups but significantly fewer difficulties were encountered in group P than in group A. Although the spread of the anesthetic was different in the three groups, the distribution of anesthesia in the lower extremity was similar, including not only dermatomes supplied by the sciatic nerve, but also those supplied by the posterior femoral cutaneous nerve. No neurological sequelae were observed. It is concluded that the posterior and lateral approaches are the most suitable in children for blocking the sciatic nerve proximally.

Plasma bupivacaine concentrations during caudal analgesia and ilioinguinal-iliohypogastric nerve block in children.

Plasma bupivacaine concentrations were measured in 27 children aged 3-7 years who received one of two analgesic regimens for herniotomy or orchidopexy. Analgesia was provided either by caudal epidural bupivacaine 0.2% 2 mg/kg (n = 14) or by ilioinguinal-iliohypogastric nerve block with bupivacaine 0.5% 1.25 mg/kg (n = 13). Mean (SD) peak venous bupivacaine concentrations were 0.57 (0.17) microgram/ml and 0.79 (0.38) microgram/ml respectively. Time to peak plasma concentrations were 29.6 (7.9) and 22.3 (10.9) minutes respectively. These concentrations are well below the potentially toxic level of 4.0 micrograms/ml, but suggest that uptake of bupivacaine is more rapid after ilioinguinal-iliohypogastric nerve block than during caudal analgesia.

Anterior Approach to Sciatic Nerve Block in Children

Anterior Approach to Sciatic Nerve Block in Children

Bupivacaine for Intercostal Nerve Blocks in Children

A pharmacokinetic evaluation of bupivacaine was carried out after intercostal nerve blocks performed on 28 occasions in 27 children varying in age from 3 months to 16 yr. Bupivacaine HCl, 0.5%, with epinephrine 1:200,000 was employed. Doses of 2 mg/kg, 3 mg/kg, and 4 mg/kg resulted in peak whole blood arterial bupivacaine (base) concentrations (mean +/- SD) of 0.77 +/- 0.25 microgram/ml, 1.37 +/- 0.23 microgram/ml, and 1.87 +/- 0.53 microgram/ml, respectively. Calculated pharmacokinetic parameters (mean +/- SD) were the following: apparent volume of distribution (VD beta), 2.8 +/- 0.8 L/kg; steady-state volume of distribution (VDss), 2.7 +/- 0.7 L/kg; elimination half-life (t1/2 beta), 147 +/- 80 min; and total body clearance (Cl), 16.0 +/- 7.4 ml X min-1 X kg-1, or 382 +/- 201 ml X min-1 X m-2. Compared with data reported for adult patients, our data indicate that the volume of distribution is greater and clearance is more rapid in children than in adults. The absorption of local anesthetic from the intercostal space appears to be more rapid in children than adults. In an additional group of 11 children, the relationship of the bupivacaine blood:plasma concentration ratio (lambda) to hematocrit was investigated. Hematocrit in this group ranged from 30 to 59, and lambda varied from 0.47 to 0.82. There was a significant relationship between lambda and hematocrit defined by the equation lambda = -0.0079 Hct + 1.028 (r = 0.72, P less than 0.05). Reporting bupivacaine concentration in terms of plasma concentration may introduce an artifact that is dependent on the hematocrit, and we therefore suggest that whole blood concentration values be reported by investigators in the future.