Caudal ropivacaine in infants: population pharmacokinetics and plasma concentrations. (9/65)

BACKGROUND: Ropivacaine is a new long-acting amino-amide local anesthetic. However, there are no data on its use in infants. In the current study, the authors investigated the pharmacokinetics of caudal ropivacaine in 30 infants younger than 12 months. METHODS: Two groups of infants (group 1 [n = 15], aged 0-3 months; group 2 [n = 15], aged 3-12 months) were given a caudal bolus dose of 0.2% ropivacaine (2 mg/kg) and a standardized general anesthetic technique. Serial blood samples taken for up to 12 h were analyzed for total and free ropivacaine using high-performance liquid chromatography. Population pharmacokinetic modeling was performed to yield estimates of clearance, volume of distribution, and absorption rate constant. An analysis of covariates on the kinetic parameters also was made. RESULTS: Median maximum free ropivacaine concentration was significantly higher in group 1 (99 micog/l) than in group 2 (38 microg/l) (P = 0.0002), as was the median free fraction of ropivacaine (10% vs. 5%; P = 0.01). Pharmacokinetic variables of the total population were best described by a one-compartment model with first-order absorption. Mean clearance was 0.31 l.h(-1).kg(-1) (coefficient of variation [CV], 51%), volume of distribution was 2.12 l/kg (CV, 34%), and absorption rate constant was 1.61 h(-1) (CV, 46%). Mean absorption and elimination half-lives were 0.43 and 5.1 h, respectively. Age and percentage of free ropivacaine were significant covariates for clearance. Posterior Bayesian estimates of clearance were significantly higher (38%) in older children. CONCLUSION: Total and free plasma ropivacaine concentrations after caudal ropivacaine (0.2%, 2 mg/kg) in infants were within the range of concentrations previously reported in adults and older children. Age and percentage of free ropivacaine were significant covariates of clearance.  (+info)

Decreased risk of catheter infection in infants and children using subcutaneous tunneling for continuous caudal anesthesia. (10/65)

Continuous caudal anesthesia has been commonly used for intra- and post-operative analgesia in infants and children. However, it has a potential risk of bacterial infection, especially in infants in whom the catheter site is easily contaminated with loose stool. To avoid infection, the authors applied a new procedure using subcutaneous tunneling for continuous caudal anesthesia. In the 18 cases studied with subcutaneous tunneling, clinical signs of infection were absent and bacterial colonization was not found on the catheter tip after 3.9 +/- 1.4 days of catheterization. The incidence of catheter colonization after continuous caudal anesthesia without tunneling had been reported. In their reports, the incidence of catheter colonization ranged from 20% to 37%. Therefore, caudal catheterization with subcutaneous tunneling is a simple and safe method, and has proved very effective to reduce the risk of epidural infection.  (+info)

Paediatric regional anaesthesia, a survey of practice in the United Kingdom. (11/65)

BACKGROUND: A variety of techniques and drugs, many unlicensed, is used in paediatric regional anaesthesia. This study is the first to survey paediatric anaesthetists about the techniques and drugs used in paediatric regional anaesthesia. The aim is to provide a record and benchmark of UK practice. METHODS: A postal questionnaire was sent to all members of the Association of Paediatric Anaesthetists residing in the UK. Information was requested on the type of hospital worked in, years of practice, paediatric anaesthesia workload, regional anaesthesia techniques used, and drugs used in regional anaesthesia. RESULTS: A total of 220 responses from 264 questionnaires (83.3%) were received. Of these respondents, 155 (70%) practised paediatric anaesthesia as more than 50% of their workload, and 10 had retired or returned blank forms. Two hundred and two of 210 (96%) use caudal anaesthesia and 151 (72%) use caudal, epidural and peripheral block. One hundred and ninety-two of 210 (91%) have no lower age limit for using caudal anaesthesia. One hundred and twenty-three of 210 anaesthetists (58%) used adjuvants with local anaesthetics in caudal block, the most common being fentanyl [44/210 (21%)], clonidine [55/210 (26%)], diamorphine [27/210 (13%)] and ketamine [67/210 (32%)]. Those working in specialist centres or teaching hospitals or who had a greater paediatric anaesthesia workload were more likely to use a greater variety of regional anaesthesia techniques. CONCLUSIONS: Caudal anaesthesia is widely used for patients of all ages by almost all practitioners. Most anaesthetists at all hospital types and experience levels use adjuvants with local anaesthetics when performing caudal anaesthesia. Those with more experience in paediatric anaesthesia and those in specialist centres commonly use other neuraxial and peripheral block techniques.  (+info)

The 'swoosh' test--an evaluation of a modified 'whoosh' test in children. (12/65)

BACKGROUND: Caudal analgesia is widely used in paediatric anaesthetic practice. In adults, the 'whoosh' test has been recommended as a guide to successful needle insertion, but it has not been extensively studied in paediatric patients. We have investigated a modification of the 'whoosh' test, which we have christened the 'swoosh' test. It avoids the injection of air by performing auscultation during injection of the local anaesthetic solution. We have compared it with clinical judgement of correct placement. METHODS: We studied 113 children undergoing elective surgery. During insertion of the caudal block, a stethoscope was placed over the lower lumbar spine and the presence or absence of an audible 'swoosh' noted. The operator's clinical impression of successful insertion was also recorded. RESULTS: The overall success rate of caudal anaesthesia was 95.6%. Of the 108 patients with a successful block, 98 had a positive 'swoosh' test. There were no false positive results. Calculations show the 'swoosh' test to have a sensitivity of 91%, a specificity of 100% and a positive predictive value of 100%. CONCLUSIONS: The 'swoosh' test is a simple and accurate test to confirm successful caudal insertion in children, and is especially useful as a teaching aid for anaesthetists new to the technique.  (+info)

Caudal ropivacaine and neostigmine in pediatric surgery. (13/65)

BACKGROUND: Neostigmine has been added to local anesthetics for different nerve blocks. This study was conducted to evaluate effects of neostigmine when added to ropivacaine for caudal anesthesia. METHODS: We studied children, aged 1-5 yr, undergoing inguinal hernia and hypospadias surgery. After standard induction of anesthesia, Group I received 0.2% ropivacaine 0.5 ml/kg and Group II received 0.2% ropivacaine 0.5 ml/kg with 2 microg/kg neostigmine via the caudal route. Heart rate, mean arterial pressure, and pulse oximetry were recorded before induction, after induction, and then every 10 min after caudal anesthesia. Hemodynamic, Toddler-Preschooler Postoperative Pain Scale pain score, and sedation score values were recorded 30 min after extubation and at hours 2, 4, 6, 12, and 24. A pain score greater than 3/10 resulted in administration of rectal paracetamol. RESULTS: There were no differences between the groups in demographic and hemodynamic data, duration of surgery and anesthesia, time to extubation, or sedation scores. The pain scores were significantly lower in Group II at 6 and 12 h (P < 0.05). Time to first analgesic requirement was statistically prolonged in Group II (19.2 +/- 5.5h) when compared with Group I (7.1 +/- 5.7 h) (P < 0.05). Total analgesic consumption was statistically larger in Group I (174 +/- 96 mg) when compared with Group II (80 +/- 85.5 mg) (P < 0.05). The incidence of vomiting (3 patients in Group II and 1 patient in Group I) was not statistically significantly different. CONCLUSIONS: The authors found that a single caudal injection of neostigmine when added to ropivacaine offers an advantage over ropivacaine alone for postoperative pain relief in children undergoing genitourinary surgery.  (+info)

Effect of ketoprofen, lidocaine local anesthesia, and combined xylazine and lidocaine caudal epidural anesthesia during castration of beef cattle on stress responses, immunity, growth, and behavior. (14/65)

To determine the effects of burdizzo castration alone or in combination with ketoprofen (K), local anesthesia (LA), or caudal epidural anesthesia (EPI) on plasma cortisol, acute-phase proteins, interferon-gamma production, growth, and behavior of beef cattle, 50 Holstein x Friesian bulls (13 mo old, 307 +/- 5.3 kg) were assigned to (n = 10/treatment): 1) control (handled; C); 2) burdizzo castration (B); 3) B following K (3 mg/ kg of BW i.v.; BK); 4) B following LA (8 mL into each testis and 3 mL s.c. along the line where the jaws of the burdizzo were applied with 2% lidocaine HCl; BLA); and 5) B following EPI (0.05 mg/kg of BW of xylazine HCl and 0.4 mg/kg of BW of lidocaine HCl as caudal epidural; BEPI). The area under the cortisol curve against time was lower (P < 0.05) in BK than in B, BLA, or BEPI animals. On d 1 after treatment, plasma haptoglobin concentrations were higher (P < 0.05) in B, BLA, and BEPI than in BK animals. On d 3, haptoglobin and plasma fibrinogen concentrations were higher (P < 0.05) in all castration groups than in C. On d 7, haptoglobin and fibrinogen concentrations remained higher (P < 0.05) in BLA than in B and C animals. On d 1, concanavalin A-induced interferon-gamma production was lower (P < 0.05) in B, BLA, and BEPI than in C, but there was no difference between BK and C animals. From d -1 to 35, ADG was lower (P < 0.05) in B, BLA, and BEPI animals, but not in BK compared with C animals. Overall, there was a higher (P < 0.05) incidence of combined abnormal postures in B than in C, BK and BEPI animals. Although the use of K and EPI decreased (P < 0.05) these postures compared with B alone or B with LA, there was no difference between the K and EPI treatment. In conclusion, burdizzo castration increased plasma cortisol and acute-phase proteins, and suppressed immune function and growth rates. Local anesthesia prolonged the increase in acute-phase proteins. Ketoprofen was more effective than LA or EPI in decreasing cortisol and partially reversed the reduction in ADG following castration. The use of K or EPI was more effective than LA in decreasing pain-associated behavioral responses observed during the first 6 h after treatment. Systemic analgesia with ketoprofen, a non-steroidal antiinflammatory drug, was more effective in reducing inflammatory responses associated with castration than LA or EPI.  (+info)

Pharmacokinetics of levobupivacaine 0.25% following caudal administration in children under 2 years of age. (15/65)

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.  (+info)

Double-blind randomized controlled trial of caudal versus intravenous S(+)-ketamine for supplementation of caudal analgesia in children. (16/65)

BACKGROUND: The postoperative analgesic efficacy of S(+)-ketamine after caudal or i.v. administration following sub-umbilical surgery in children was studied to investigate its principal site of analgesic action. METHODS: Sixty children undergoing caudal block during general anaesthesia for hernia repair or orchidopexy were prospectively randomized to one of three groups: the bupivicaine group received plain bupivacaine 0.25% 1 ml x kg(-1); the caudal ketamine group received caudal plain bupivacaine 0.25% 1 ml x kg(-1) with S(+)-ketamine 0.5 mg x kg(-1); the i.v. ketamine group received caudal plain bupivacaine 0.25% 1 ml x kg(-1) plus S(+)-ketamine 0.5 mg x kg(-1) i.v. Postoperative measurements included analgesic requirements and modified objective pain score for the first 24 h. RESULTS: The median time to first analgesia was significantly longer in the caudal ketamine group (10 h) than in the i.v. ketamine (4.63 h) or bupivacaine (4.75 h) groups (P=0.01). Significantly fewer doses of analgesia were required over the first postoperative 24 h by subjects in the caudal ketamine group (median 1) compared with the i.v. ketamine (median 2) or bupivacaine (median 2.5) groups (P<0.05). There was no difference between the groups in the incidence of postoperative nausea and vomiting or psychomotor reactions. CONCLUSIONS: We have demonstrated that the addition of caudal S(+)-ketamine to bupivacaine prolongs the duration of postoperative analgesia. However, the same dose of i.v. S(+)-ketamine combined with a plain bupivacaine caudal provides no better analgesia than caudal bupivacaine alone, indicating that the principal analgesic effect of caudal S(+)-ketamine results from a local neuroaxial rather than a systemic effect.  (+info)