Thermoregulatory thresholds for vasoconstriction in pediatric patients anesthetized with halothane or halothane and caudal bupivacaine.
(17/65)
The thermoregulatory threshold for vasoconstriction has been studied in infants and children given isoflurane, but not in those given halothane anesthesia. More importantly, the effect of vasoconstriction on central temperature in pediatric patients remains unknown. Also unknown is the effect of caudal analgesia on vasoconstriction thresholds. Accordingly, in the first portion of this study, we determined the central thermoregulatory threshold in 23 infants and children given approximately 0.6% halothane and caudal anesthesia for abdominal surgery. Patients were prospectively assigned to one of four weight groups: 5-10, 10-20, 20-30, and 30-50 kg. The threshold was considered the central temperature triggering peripheral vasoconstriction, and significant vasoconstriction was defined as a forearm-fingertip skin-surface temperature gradient exceeding 4 degrees C. Thresholds were similar (approximately 35.7 degrees C) in each study group, suggesting that thermoregulatory responses to halothane anesthesia are similar in infants and children of differing weights. However, they were higher than expected based on the previously reported thresholds in pediatric patients given isoflurane anesthesia. After peripheral vasoconstriction, central temperature continued to decrease in patients weighing more than 30 kg but remained constant or increased slightly in the others. These data suggest that thermoregulatory responses are more effective in infants and small children than in bigger children or adults. In the second part of this study we evaluated the effect of caudal analgesia on the thermoregulatory threshold for vasoconstriction. Children undergoing hypospadias repair were anesthetized with halothane (0.9%) and oxygen. Following induction, they were randomly assigned to caudal analgesia (n = 7) or penile nerve block (n = 6).(ABSTRACT TRUNCATED AT 250 WORDS) (+info)
Randomized, double-blind, phase III, controlled trial comparing levobupivacaine 0.25%, ropivacaine 0.25% and bupivacaine 0.25% by the caudal route in children.
(18/65)
BACKGROUND: The rationale for replacing racemic bupivacaine with the s-enantiomers levobupivacaine and ropivacaine is to provide a wider margin of safety with the same analgesic efficacy and less postoperative motor block. In a randomized, double-blind, phase III, controlled trial we compared the caudal administration of levobupivacaine 0.25% and ropivacaine 0.25% with bupivacaine 0.25% in children. METHODS: Ninety-nine ASA I-II children less than 10 yr old scheduled for elective sub-umbilical surgery were randomized to receive caudal block with bupivacaine 0.25%, ropivacaine 0.25% or levobupivacaine 0.25%. The primary outcome of the study was the clinical efficacy of the caudal block during the operation. Secondary outcome measures were analgesic onset time, pain relief after the operation and residual motor blockade. RESULTS: The proportion of children with effective analgesia during the operation was similar among groups. There were no significant differences in the analgesic onset time of the caudal block. Bupivacaine produced a significant incidence of residual motor block compared with levobupivacaine or ropivacaine at wake-up (P<0.01). There were no significant differences in the number of patients receiving rescue analgesia after surgery. However, analgesic block lasted significantly longer in patients receiving bupivacaine (P=0.03). CONCLUSION: During sub-umbilical surgery, caudal levobupivacaine, ropivacaine and bupivacaine provided comparable analgesic efficacy. Bupivacaine produced a higher incidence of residual motor blockade and a longer analgesic block than ropivacaine and levobupivacaine. (+info)
Central blocks with levobupivacaina in children.
(19/65)
Regional anesthesia has become a routine practice in paediatric anesthesia and local anaesthetics are now widely used in infants and children. Although local anaesthetics are generally quite safe and effective, they may produce systemic toxic reactions affecting the heart and brain. Because postoperative analgesia is often the primary justification for regional anesthesia in infants and children, bupivacaine, a long-acting local anaesthetic, is the most commonly used local anaesthetic for paediatric regional anesthesia. Levobupiva-caine has been used in children by caudal injection, by lumbar epidural route for anesthesia during operation, by continuous epidural infusion for pain control after operation and for spinal anesthesia. Levobupivacaine had shown comparable clinical profiles to that of bupivacaine but produced lower incidence of residual motor blockade. Efforts to minimize the risk of complications during caudal anesthesia must be directed towards measures that reduce accidental intravenous and intraosseous injections, reduce the total amount of local anaesthetic used and use drugs with lower toxic potential. In patients under general anesthesia, when using a large amount of local anaesthetic, in case of accidental intravenous infusion, patients receiving levobupivacaine may tolerate larger doses before manifestation of toxicity compared with those receiving bupivacaine. There are clinical situations including prolonged local anaesthetic infusions, use in neonates or small babies, and caudal block, where replacement of bupivacaine with levobupivacaine appears to be safer. (+info)
Thoracic epidural anesthesia via the caudal approach in children.
(20/65)
We investigated the feasibility of performing thoracic epidural anesthesia via the caudal approach in 20 children (age 62 +/- 38 months and weight 18.5 +/- 7.3 kg; mean +/- standard deviation). Based on external landmarks, a predetermined length of 24-G epidural catheter (Concord Portex 20/24 microcatheter system) with stylet was passed into the epidural space through a 20-G intravenous catheter inserted through the sacrococcygeal ligament, and a radiograph of the abdomen and chest was obtained. The radiographically determined catheter tip position was within two vertebrae of the target position in 17 of 20 subjects. In one subject, it was impossible to advance the catheter more than 10 cm. The other two malpositioned catheters were successfully reinserted. Intraoperative caudal anesthesia and postoperative pain relief were satisfactory in all 20 subjects. We have found it possible to use the caudal approach to thoracic epidural anesthesia in children as old as 10 yr. Ease of removal of the stylet, ease of injection, and negative aspiration and test doses predict successful placement and obviate the need for routine radiographic confirmation of catheter position. (+info)
Pharmacokinetics of levobupivacaine after caudal epidural administration in infants less than 3 months of age.
(21/65)
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. (+info)
Landmarks of the sacral hiatus for caudal epidural block: an anatomical study.
(22/65)
BACKGROUND: This study determined the landmarks for caudal epidural block (CEB) after morphometric measurements of the sacral hiatus on dry sacral bones. Anatomical features of the sacral hiatus of clinical importance during CEB, along with distances and angles of use in detecting the apex, were measured. This provides detailed knowledge of the anatomy of the sacral hiatus and practical landmarks. METHODS: Ninety-six dry sacral bones were used. Anatomical measurements were made with a Vernier caliper accurate to 0.1 mm. RESULTS: Two sacral bones were excluded since they had total posterior closure defect. Agenesis of the sacral hiatus was detected in six sacral bones. As the posterior superior iliac spines impose on the superolateral sacral crests of the sacrum, the latter were accepted as forming the base of a triangle. The distance between the two superolateral sacral crests and the distances between the sacral apex and the right and left superolateral sacral crest were 66.5 (SD 53.5), 67.1 (10.0) and 67.5 (9.5) mm respectively, on average. CONCLUSION: The triangle formed between the apex of the sacral hiatus and the superolateral sacral crests was found to have the features of an equilateral triangle. The sacrum and sacral hiatus are variable anatomical structures. However, the equilateral triangle located between the apex of the sacral hiatus and superolateral sacral crests will certainly be of use in determining the location of the sacral hiatus during CEB. (+info)
Obstetric anesthesia - then and now.
(23/65)
In 1947 John Bonica as new Chief of Anesthesiology at Tacoma General Hospital organized one of the first around-the-clock labor anesthesia services and when became the first chairman of the new Department of Anesthesiology at the University of Washington (1960), caudal anesthesia was the primary technique used for providing labor analgesia. In 1967 the first volume of Bonica's classic textbook ''Principles and practice of obstetric analgesia and anesthesia'' was published. The text was a comprehensive treatise that pulled together virtually everything that was known in that field. Perhaps the most significant development in obstetric anesthesia in the past 20 years has been the introduction of spinal opioid analgesia.. Bonica predicted the probable success of these techniques in the last edition of his ''Obstetric analgesia and anesthesia'' handbook published in 1980. Current obstetric anesthetic practice, though quite different from what it was 30 or 40 years ago, has its roots in the priorities, techniques and teachings of Dr. John J. Bonica. (+info)
Caudal anesthesia in pediatrics: an update.
(24/65)
AIM: Caudal anesthesia is one of the most used-popular regional blocks in children. This technique is a useful adjunct during general anesthesia and for providing postoperative analgesia after infraumbilical operations. The quality and level of the caudal blockade is dependent on the dose, volume, and concentration of the injected drug. Although it is a versatile block, one of the major limitations of the single-injection technique is the relatively short duration of postoperative analgesia. The most frequently used method to further prolong postoperative analgesia following caudal block is to add different adjunct drugs to the local anesthetics solution. Only few studies evaluated quality and duration of caudal block against the volume of the local anaesthetic applied. After reviewing recent scientific literature, the authors compare the duration of postoperative analgesia in children scheduled for hypospadia repair when 2two different volumes and concentrations of a fixed dose of ropivacaine are used. METHODS: After informed parental consent, 30 children (ASA I, 1-5 years old) were enrolled in a multicentre, perspective, not randomized, observational study conducted in two 2 children hospitals. After premedication with midazolam, anesthesia was induced with thiopental and maintained with sevoflurane in oxygen/air. After induction, patients received a caudal blockade either with ropivacaine 0.375% at 0.5 mL/kg (Low Volume High Concentration Group, LVHC; n = 15), or ropivacaine 0.1% at 1.8 mLl/kg (High Volume Low Concentration Group, HVLC; n = 15). Surgery was allowed to begin 10ten minutes after performing the block. MAC-hour was calculated. In the recovery room, pain was assessed using the Children's Hospital of Eastern Ontario Pain Scale (CHEOPS). In addition, the motor block was scored. After transferral to the ward, the patients were observed for 24 hours for signs of postoperative pain. The time period to first supplemental analgesic demand, i.e., from establishment of the block until the first registration of a CHEOPS score = or > 9, was considered the primary endpoint of the study. The time periods were compared using analysis of variance adjusted for age, weight and duration of surgical procedure as covariates. RESULTS: All patients were judged to have sufficient intraoperative analgesia, and none of them received additional analgesics intraoperatively. Patients' characteristics were similar, besides the age (32+/-10 vs 24 +/- 9 months; P < 0.05) and weigh (15.13 +/- 3.92 vs 11.93 +/- 1.83; P = 0.08). Analgesics were needed after 520 +/- 480 min in the LVHC and 952 +/- 506 min in the HVLC group (P < 0.05). Motor block was less in the HVLC group. CONCLUSIONS: In children undergoing hypospadia repair, caudal block with a ''high volume, low concentration'' regimen produces prolonged analgesia and less motor block, compared to a ''low volume, high concentration'' regimen. (+info)