The effects of caudal or intravenous clonidine on postoperative analgesia produced by caudal levobupivacaine in children

Background: Clonidine is used increasingly in pediatric anesthesia practice to prolong the duration of action of caudal block with a local anesthetic agent. Which route of administration of clonidine is the most beneficial remains unknown. We compared the effects of caudal and intravenous clonidine on postoperative analgesia produced by caudal levobupivacaine. Methods: Sixty ASA I and II children, aged 2–8 undergoing inguinal hernia repair or orchidopexy surgery received standardized premedication with midazolam and general anesthesia. The children were randomized in a double‐blind fashion to three groups. Group L (n = 20) patients received 0.75 ml·kg^?1 of caudal 0.25% levobupivacaine and i.v. 5 ml saline, Group L‐Ccau (n = 20) patients received 0.75 ml·kg^?1 of caudal 0.25% levobupivacaine + 2 μg·kg^?1 clonidine and i.v. 5 ml saline, Group L‐Civ (n = 20) patients received 0.75 ml·kg^?1 of caudal 0.25% levobupivacaine and i.v. 2 μg·kg^?1 clonidine in 5 ml of saline. Mean arterial blood pressure, heart rate, peripheral oxygen saturation, and end‐tidal carbon dioxide values were recorded. Postoperative pain [Children and Infants Postoperative Pain Scale (CHIPPS) score], sedation (Ramsay Sedation Scale) and motor blockade (Modified Bromage Scale) were assessed at predetermined time points during the first 24 h after surgery. Results: Caudal clonidine significantly delayed the time to first rescue analgesic and fewer patients required rescue analgesia in the 24 h after surgery. No motor block was observed in any of the three groups on awakening or during the study period. In Group L‐Ccau, the CHIPPS score was lower than in Group L at all times through 240 min (P < 0.05), while the pain scores were lower in Group L‐Civ only at extubation and at 240 min (P < 0.05). Conclusions: Caudal clonidine prolongs the duration of analgesia produced by caudal levobupivacaine without causing significant side effects and this is because of a spinal mode of action.     

An evaluation of intrathecal bupivacaine combined with intrathecal or intravenous clonidine in children undergoing orthopedic surgery: a randomized double-blinded study

Background: Propofol is a popular agent for providing intraoperative sedation in pediatric population during lumbar puncture and spinal anesthesia. Adjuvant‐like clonidine is used increasingly in pediatric anesthesia to provide postoperative analgesia with a local anesthetic agent. The aim of this study was to assess the effects of intrathecal and intravenous clonidine on postoperative analgesia/sedation and intraoperative requirements of propofol after intrathecal bupivacaine for orthopedic surgery in children. Methods: Fifty‐nine ASA I and II children aged 6–8 year undergoing orthopedic surgery were randomized to receive intrathecal 0.5% bupivacaine 0.2–0.4 mg·kg^?1 and intravenous 2 ml saline (Group B), intrathecal 0.5% bupivacaine 0.2–0.4 mg·kg^?1 plus 1 μg·kg^?1 clonidine and intravenous 2 ml saline (Group BCit), and 0.5% bupivacaine 0.2–0.4 mg·kg^?1 and intravenous 1 μg·kg^?1 clonidine in 2 ml of saline (Group BCiv). Intraoperative sedation was maintained with 20–50 μg·kg^?1·min^?1 of propofol infusion. The requirements of propofol, time to first rescue analgesia, and postoperative pain or sedation scores were assessed. The duration of motor and sensory blocks and perioperative adverse events were determined. Results: Clonidine significantly prolonged the time to first rescue analgesia and reduced the requirements of propofol sedation whether administered intravenously or intrathecally. The mean Children and Infants Postoperative Pain Scale scores of children were significantly lower in groups BCit and BCiv than in group B. Postoperative sedation scores were higher in groups BCit and BCiv than in group B. Intrathecal clonidine significantly prolonged the time to regression of the sensory block and recovery of motor block. There were no significant differences among the three groups regarding the incidence of perioperative adverse events. Conclusion: Intrathecal or intravenous clonidine similarly provided better postoperative analgesia and sedation and reduced the requirements of propofol. Only intrathecal clonidine prolonged the duration of sensory and motor blocks.     

Two different doses of caudal neostigmine co-administered with levobupivacaine produces analgesia in children

Background: This study was aimed to evaluate the analgesic efficacy, duration of analgesia, and side effects of two different doses of caudal neostigmine used with levobupivacaine in children. Methods: Sixty boys, between 5 months and 5 years, undergoing genito‐urinary surgery were allocated randomly to one of three groups (n = 20 each). Group I patients received caudal 0.25% levobupivacaine (1 ml·kg^?1) alone. Groups II and III patients received neostigmine (2 and 4 μg·kg^?1 respectively) together with levobupivacaine used in the same dose as Group I. Pain scores were assessed using Children’s and Infant’s Postoperative Pain Scale (CHIPPS) at 15th (t₁) min after arrival to postanesthetic care unit, and 1st (t₂), 2nd (t₃), 3rd (t₄), 4th (t₅), 8th (t₆), 16th (t₇), and 24th (t₈) hour postoperatively. Duration of analgesia, amount of additional analgesic (paracetamol), score of motor blockade and complications were recorded for 24 h postoperatively, and compared between groups. Results: CHIPPS scores were higher during t₂, t₃, t₆, t₇ and t₈ periods, duration of analgesia was shorter, and total analgesic consumption was higher in Group I compare to neostigmine groups (P < 0.05). Duration of postoperative analgesia and total analgesic consumption were similar in Groups II and III (P > 0.05). Adverse effects were not different between three groups. Conclusions: Caudal neostigmine in doses of 2 and 4 μg·kg^?1 with levobupivacaine extends the duration of analgesia without increasing the incidence of adverse effects, and 2 μg·kg^?1 seems to be the optimal dose, as higher dose has no further advantages.     

Clonidine-mepivacaine mixture vs plain mepivacaine in paediatric surgery

In a double-blind study, 42 children, aged 1–10, undergoing general subumbilical surgery, were randomly allocated to two groups; they received, via caudal extradural, 1% mepivacaine 7 mg·kg^?1 and normal saline 1 ml (Group 1) and a mixture of 1% mepivacaine 7 mg·kg^?1 plus clonidine 2 μg·kg^?1 and normal saline up to 1 ml (Group 2) respectively. No significant difference was noticed in age, weight, duration of surgery and onset time of anaesthesia, blood pressure, heart rate and oxygen saturation. Mean duration of analgesia (evaluated with ‘Broadman objective pain scale') was 143 min for Group 1 and 218 min for Group 2 (P < 0.05); the time of sedation (evaluated with a sedation score) was statistically longer in Group 2 (172 min vs 89 min in Group 1). This longer sedation is due both to the longer analgesia and partially to a side effect of clonidine. In conclusion the addition of 2 μg·kg^?1 of clonidine to mepivacaine prolongs the duration of caudal analgesia in children.     

Caudal clonidine and bupivacaine for combined epidural and general anaesthesia in children

Background: Clonidine produces analgesia by actions on α₂-ad-renoceptors and enhances both sensory and motor blockade from epidural injection of local anaesthetics. Low-dose clonidine has been used so far for caudal injection in children. Our aim was to study the perioperative effects of high-dose caudal clonidine when added to low concentration of bupivacaine for combined epidural and general anaesthesia in children. Methods: After induction of general anaesthesia caudal block was performed either with 1 ml kg^-1 bupivacaine 0.175% with the addition of clonidine 5 μg kg^-1 (n=20), or with 1 ml kg^-1bupivacaine 0.175% (n=20). The intraoperative anaesthetic requirements, the perioperative haemodynamic effects, respiratory rate, sedation score, postoperative pain scores and side effects were assessed by a blinded observer. A patient-controlled analgesia system was used for postoperative pain relief. The quality of postoperative pain relief was assessed using Smiley's pain analogue scale. Results: Intraoperative haemodynamic responses did not differ between the groups. However, during emergence from general anaesthesia children in the clonidine group had significantly lower heart rates and blood pressures compared to children in the control group. In addition, heart rates and blood pressures were also lower in the clonidine group in the early postoperative period (P?< 0.05). Postoperative analgesia was significantly better in the clonidine group as evidenced by the total number of requests (3 vs 12, P< 0.05) and the total amount of tramadol (20.5 mg vs 72.8 mg, P < 0.05) administered. The duration of the caudal analgesia was significantly longer in the clonidine group (20.9±7.4 h vs 14.4±10.9 h, P< 0.05). Conclusion: Our results suggest that caudal clonidine 5 μg kg^-1 enhances and prolongs caudal blockade with bupivacaine 0.175% in children. It also blocks sympathoadrenergic responses during emergence from anaesthesia. Sedation and cardiovascular effects are observed up to 3 h into the postoperative period.     

The effect of caudal vs intravenous morphine on early extubation and postoperative analgesic requirements for stage 2 and 3 single-ventricle palliation: a double blind randomized trial

Background: High‐dose single‐shot caudal morphine has been postulated to facilitate early extubation and to lower initial analgesic requirements after staged single‐ventricle (SV) palliation. Methods: With Institutional Review Board approval and written informed parental consent, 64 SV children aged 75–1667 days were randomized to pre‐incisional caudal morphine–bupivacaine (100 μg·kg^?1 morphine (concentration 0.1%), mixed with 0.25% bupivacaine with 1 : 200 000 epinephrine, total 1 ml·kg^?1) and postcardiopulmonary bypass (CPB) intravenous (IV) droperidol (75 μg·kg^?1) (‘active caudal group’) or pre‐incisional caudal saline (1 ml·kg^?1) and post‐CPB IV morphine (150 μg·kg^?1) with droperidol (75 μg·kg^?1) (‘active IV group’). Assignment remained concealed from families and the care teams throughout the trial. Early extubation failure rates (primary or reintubation within 24 h), time to first postoperative rescue morphine analgesia, and 12‐h postoperative morphine requirements were assessed for extubated patients. Results: Thirty‐one (12 stage 2) SV patients received caudal morphine and 32 (15 stage 2) received IV morphine. Extubation failure rates were 6/31 (19%) for caudal and 5/32 (16%) for IV morphine. For successfully extubated patients (n = 54), active caudal treatment significantly delayed the need for postoperative rescue morphine in stage 3 patients (P = 0.02) but not in stage 2 patients (P = 0.189) (Kaplan–Meier survival analysis with LogRank test). The reduction in 12‐h postoperative morphine requirements with active caudal treatment did not reach significance (P = 0.085) but morphine requirements were significantly higher for stage 2 compared with stage 3 patients (P < 0.001) (two‐way anova in n = 50 extubated patients). Conclusions: High‐dose caudal morphine with bupivacaine delayed the need for rescue morphine analgesia in stage 3 patients. All stage 2 patients required early rescue morphine and had significantly higher postoperative 12‐h morphine requirements than stage 3 patients. Early extubation is feasible for the majority of stage 2 and 3 SV patients regardless of analgesic regimen. The study was underpowered to assess differences in extubation failure rates.     

Dose-response study of intrathecal fentanyl added to bupivacaine in infants undergoing lower abdominal and urologic surgery

Background: Intrathecal (IT) adjuncts often are used to enhance the duration of spinal bupivacaine. Fentanyl is a spinal analgesic that could be a useful adjunct, and enhances the duration and quality of sensory block in adult surgical and obstetric population. However, no data exist to assess the dose–response characteristics of IT fentanyl when added to bupivacaine in infants. Methods: Fifty‐eight infants undergoing lower abdominal and urologic procedures were randomized into four groups to receive plain 0.5% hyperbaric bupivacaine F0 (<5 kg = 0.5 mg·kg^?1; 5–10 kg = 0.4 mg·kg^?1). Groups F0.25, F0.5, and F1 groups received bupivacaine added with 0.25, 0.5, and 1 μg·kg^?1 of fentanyl, respectively. Duration of spinal anesthesia (SA) as assessed by the recovery of hip flexion in the postoperative period was the primary variable analyzed. In addition, the duration of analgesia in the postoperative period, rescue postoperative analgesic requirements and hemodynamic changes were recorded. Results: Fifty‐six infants were studied. The four groups were similar for age, weight, duration of surgery, onset of sensory, motor block, and the highest level of analgesia attained. The addition of 1 μg·kg^?1 fentanyl (F1) significantly increased the duration of SA (74.27 ± 6.1 min) compared to the control group (51.21 ± 5.2 min) (P = 0.001). Postoperative pain‐free interval was prolonged (P = 0.004) and significantly less rescue analgesics were required after 1 μg·kg^?1 IT fentanyl (P = 0.032). These parameters did not show any significant difference among groups F0, F0.25, and F0.5. Conclusions: The addition of 1 μg·kg^?1 IT fentanyl to spinal bupivacaine prolonged the duration of spinal block in infants undergoing lower abdominal and urologic procedures.     

Transcutaneous CO2 tension effects of clonidine in paediatric caudal analgesia

In adults, clonidine when added to bupivacaine, results in no detectable respiratory depressant effect except when carbon dioxide challenge is performed. However, to date no investigations have quantified this in children. Twenty-four children (nine months to seven years) were randomized in a double-blind study into two groups. After induction, a caudal block was performed with 1 ml·kg^?1 0.25% bupivacaine. Clonidine 1 μg·kg^?1 was added in the clonidine group, and 1 ml normal saline in the placebo group. Patients were monitored in the recovery room for three h from arrival to discharge with continuous pulse oximetry, respiratory rate, a trancutaneous CO₂ tension (tcPCO₂) every 15 min, and a four point sedation score every 30 min. Mean tcPCO₂ and respiratory rate values were not different between the two groups. Apnoea and desaturation less than 97% were not observed. The sedation score decreased with time in both groups, and the score time interval was significantly higher in the clonidine group (P<0.05). All the patients left the recovery room with a sedation score of 1, excepting four in the clonidine group with a sedation score of 2. Clonidine 1 μg·kg^?1 with 0.25% bupivacaine mixture in caudal analgesia in children did not induce an increase in tcPCO₂ despite prolonged sedation.     

Intrathecal clonidine decreases propofol sedation requirements during spinal anesthesia in infants

Background: Propofol is a popular agent for providing procedural sedation in pediatric population during lumbar puncture and spinal anesthesia. Adjuvants like clonidine and fentanyl are administered intrathecally to prolong the duration of spinal anesthesia and to provide postoperative analgesia. We studied the propofol requirement after intrathecal administration of clonidine or fentanyl in infants undergoing lower abdominal surgeries. Methods: Sixty‐five ASA I infants undergoing elective lower abdominal surgery under spinal anesthesia were assigned into four groups in this prospective randomized double‐blinded study. Group B received bupivacaine based on body weight (<5 kg = 0.5 mg·kg⁻¹; 5–10 kg = 0.4 mg·kg⁻¹). Group BC received 1 μg·kg⁻¹ of clonidine with bupivacaine, group BF received 1 μg·kg⁻¹ of fentanyl with bupivacaine, and patients in group BCF received 1 μg·kg⁻¹ each of clonidine and fentanyl with bupivacaine. A bolus of 2–3 mg·kg⁻¹ of propofol bolus was administered for lumbar puncture. Sedation was assessed using a six‐point sedation score (0–5) and a five‐point reactivity score (0–4) which was based on a behavioral score. After achieving a sedation and reactivity score of 3–4, the patients were placed lateral in knee chest position and lumbar puncture performed and test drug administered. Further intraoperative sedation was maintained with an infusion of 25–50 μg·kg⁻¹·min⁻¹ of propofol infusion. Results: The mean ± sd infusion requirement of propofol decreased from 35.5 ± 4.5 in group B to 33.4 ± 5.4 μg·kg⁻¹·min⁻¹ in group BF and further decreased to 16.7 ± 6.2 μg·kg⁻¹·min⁻¹ and 14.8 ± 4.9 μg·kg⁻¹·min⁻¹ in group BC and BCF, respectively. There were no statistically significant differences between BC and BCF groups. The mean sedation and reactivity scores were higher in groups BC and BCF when compared to groups B and BF. Conclusion: Our study show that the requirement of propofol sedation reduces with intrathecal adjuvants. The reduction was significant with the addition of clonidine and clonidine–fentanyl combination as opposed to bupivacaine alone or with fentanyl. There was no significant difference in propofol infusion requirement with the use of bupivacaine alone or with fentanyl.     

Levobupivacaine–tramadol combination for caudal block in children: a randomized,double‐blinded,prospective study1

Background: The aim of this prospective study was to compare the postoperative analgesic efficacy and duration of analgesia after caudal levobupivacaine 0.125% or caudal tramadol 1.5 mg·kg⁻¹ and mixture of both in children undergoing day‐case surgery. Methods: Sixty‐three American Society of Anesthesiologists (ASA) I or II children between 1 and 7 years old scheduled for inguinal hernia repair under sevoflurane anesthesia were randomized to receive caudal levobupivacaine 0.125% (group L), caudal tramadol 1.5 mg·kg⁻¹ (group T) or mixture of both (group LT) (total volume of caudal solution was 1 ml·kg⁻¹). Duration of analgesia and requirement for additional analgesics were noted. Postoperative pain was evaluated using the Children’s and Infants’ Postoperative Pain Scale (CHIPPS) every 15 min for the first hour, and after 2, 3, 4, 6, 12, and 24 h. Analgesia was supplemented whenever pain score was ≥4. Results: No patient experienced significant intraoperative hemodynamic response to surgical incision. Duration of analgesia was significantly longer in group LT than in group L and group T (545 ± 160 min vs 322 ± 183 min and 248 ± 188 min, respectively) (P < 0.01). There were no significant differences between the group L and group T for duration of analgesia (P > 0.05). There were no significant differences among the groups in the number of patients requiring analgesia after operation (P = 0.7). No signs of motor block were observed after the first postoperative hour in any of the patients. Conclusion: Addition of tramadol increased the duration of analgesia produced by caudal levobupivacaine in children.     

Clonidine does not improve quality of ropivacaine axillary brachial plexus block in children

Background: The addition of clonidine to peripheral nerve blocks is controversial in children. Objective: The aim of our study was to evaluate the effect of clonidine added to ropivacaine in pediatric axillary brachial plexus block (ABPB). Methods: Children aged 1–6 years, scheduled to undergo forearm or hand surgery, were recruited into this prospective, double‐blind controlled trial. Patients were randomly allocated to receive an ABPB either with ropivacaine 0.2% 0.4 ml·kg^?1 plus saline in 1 ml (RS) or ropivacaine 0.2% 0.4 ml·kg^?1 plus clonidine 1 μg·kg^?1 in 1 ml (RC). Primary endpoints were quality of postoperative analgesia as assessed by pain scores and total 24‐h postoperative analgesia requirements. Secondary outcomes were time to first analgesia request and duration of motor blockade. Results: Sixty patients were recruited (n = 30 per group) into the study. Pain scores were comparable throughout the first 24 h between the two groups. Ten children in the (RS) and six in (RC) groups required supplementary analgesia during the first 24 h (P = 0.24). Children who required further analgesia did so after 288 ± 94 min in the (RS) and 437 ± 204 min in the (RC) group (P = 0.06). There was no difference in the duration of motor block [186 ± 71 and 154 ± 56 min, P = 0.12 for (RS) and (RC), respectively]. Conclusion: Ropivacaine (0.2% 0.4 ml·kg^?1) for ABPB provides sufficient postoperative analgesia in children scheduled for forearm or hand surgery. The addition of clonidine to ABPB does not improve overall postoperative analgesia but may increase the time to first analgesia request.     

Efficacy of bupivacaine‐neostigmine and bupivacaine‐tramadol in caudal block in pediatric inguinal herniorrhaphy

Background: Limited duration of analgesia is among the limitations of single caudal injection with local anesthetics. Therefore, the purpose of this study was to evaluate the effectiveness and safety of bupivacaine in combination with either neostigmine or tramadol for caudal block in children undergoing inguinal herniorrhaphy. Methods: In a double‐blinded randomized trial, sixty children undergoing inguinal herniorrhaphy were enrolled to receive a caudal block with either 0.25% bupivacaine (1 ml·kg^?1) with neostigmine (2 μg·kg^?1) (group BN) or tramadol (1 mg·kg^?1) (group BT). Hemodynamic variables, pain and sedation scores, additional analgesic requirements, and side effects were compared between two groups. Results: Duration of analgesia was longer in group BT (17.30 ± 8.24 h) compared with group BN (13.98 ± 10.03 h) (P = 0.03). Total consumption of rescue analgesic was significantly lower in group BT compared with group BN (P = 0.04). There were no significant differences in heart rate, mean arterial pressure, and oxygen saturation between groups. Adverse effects excluding the vomiting were not observed in any patients. Conclusion: In conclusion, tramadol (1 mg·kg^?1) compared with neostigmine (2 μg·kg^?1) might provide both prolonged duration of analgesia and extended time to first analgesic in caudal block.     

A comparison of intramuscular tenoxicam with intramuscular morphine for pain relief following tonsillectomy in children

A double blind trial was conducted to evaluate the analgesic efficacy of intramuscular tenoxicam for pain relief following tonsillectomy in children. Fifty children, aged 3–10 years, were randomly allocated to receive intramuscular tenoxicam 0.75 mg·kg^?1 or intramuscular morphine sulphate 0.2 mg·kg^?1 after induction of anaesthesia. Although the tenoxicam group required significantly more postoperative morphine (mean 57.8 μg·kg^?1 compared with 26.9 μg·kg^?1, P=0.025), the total morphine dose was significantly reduced after tenoxicam (57.8 μg·kg^?1 compared with 226.9 ug·kg^?1, P<0.0001). There was no difference between the quality of analgesia after discharge from recovery. The incidence of postoperative vomiting was significantly reduced after tenoxicam (20%) compared with morphine (71%).     

Tracheal extubation of deeply anesthetized pediatric patients: a comparison of sevoflurane and sevoflurane in combination with low‐dose remifentanil

Purpose: We aimed to observe the emergence characteristics of children tracheally extubated in deep anesthesia with sevoflurane or sevoflurane in combination with low‐dose remifentanil. Methods: We randomly allocated 50 pediatric patients undergoing elective electronic cochlear implantation to groups either receiving sevoflurane (Group S, n = 25), or sevoflurane plus low‐dose remifentanil (Group SR, n = 25), during extubation from anesthesia. In Group S, subjects were tracheally extubated while breathing 1.3 times the minimal effective concentration of sevoflurane. In Group SR, subjects were tracheally extubated while breathing 1.0 times the minimal effective concentration of sevoflurane with 0.02–0.05 μg·kg^?1 per min remifentanil. Recovery characteristics and airway complications were noted. Results: There was no significant difference in age, weight, sex, and duration of anesthesia. The average remifentanil rate was 0.036 μg·kg^?1 per min, and compared with Group S, patients in Group SR had a lower respiratory rate (17.3 vs 20.2 per minute, P < 0.05) and a higher ETCO₂ (52.3 vs 49.4 mmHg, P < 0.05). Oral airway usage was also less frequent in Group SR (44% vs 16%, P < 0.01). Additionally, the time from extubation to spontaneous eye opening was shorter in Group SR (10.9 min vs 19.6 min, P < 0.01). Finally, six patients in Group S and five patients in Group SR had a pediatric anesthesia emergence delirium score >10. Conclusions: Low‐dose remifentanil in combination with sevoflurane provided rapid recovery and was safe for deep tracheal extubation in deep anesthesia in pediatric patients.     

Oral clonidine premedication reduces vomiting in children after strabismus surgery

This is a prospective randomized double-blind trial conducted to determine whether preoperative orally administered clonidine causes or potentiates postoperative vomiting in 140 children (3–12 yr) undergoing strabismus surgery. They were all inpatients and classified randomly into four groups (n = 35 each); placebo (control), diazepam 0.4 mg · kg^?1, clonidine 2 μg · kg^?1, and clonidine 4 μg · kg^?1. These agents were administered 93–112 min (mean: 100 min) before the anticipated time of induction of anaesthesia. All children received inhalational anaesthesia with halothane and nitrous oxide in oxygen.’ Muscle relaxation in all patients was obtained with vecuronium and residual neuromuscular blockade was antagonized with neostigmine and atropine before tracheal extubation. Diclofenac suppository was prescribed to prevent postoperative pain. No opioids or postoperative antiemetics were administered. All children remained in hospital for two days postoperatively. The incidence and frequency of vomiting were compared in the groups with Kruskall-Wallis Rank test. Clonidine 4 μg · kg^?1 caused a lower incidence and frequency of vomiting than did placebo and diazepam (incidence and frequency: 11% and 1,37% and 3, and 34% and 2 in clonidine 4 μg · kg^?1, placebo, and diazepam, respectively; P < 0.05 for clonidine 4 μg · kg^?1 vs placebo and diazepam). However, lowdose clonidine was ineffective. These data suggest that preanaesthetic medication with clonidine 4 μg · kg^?1 may be useful for preventing emesis following strabismus surgery. This property of clonidine indicates that it may be superior to other sedative premedicants such as diazepam and midazolam.     

Effects of intrathecal fentanyl on quality of spinal anesthesia in children undergoing inguinal hernia repair

Background: The effect of intrathecal fentanyl on the characteristics of spinal anesthesia has not been investigated in children undergoing inguinal hernia repair. The purpose of this study was to assess whether the incidence and severity of pain during peritoneal sac traction is decreased by addition of fentanyl to bupivacaine in children undergoing inguinal hernia repair with spinal anesthesia. Methods: Children (6–14 years) were randomized into two groups. Group F (n = 25): hyperbaric bupivacaine plus 0.2 μg·kg⁻¹ of fentanyl. Group P (n = 25): hyperbaric bupivacaine plus 0.9% NaCl (placebo). The dose of bupivacaine was 0.4 mg·kg⁻¹. The primary variable was the incidence and severity of pain during peritoneal sac traction. Spinal block characteristics, duration of spinal anesthesia assessed by recovery of hip flexion and duration of analgesia were the secondary variables measured, and the side effects were noted. Results: There were significant differences in incidence of pain and pain scores during sac traction with lower incidence and scores in the fentanyl group (P = 0.009). Two groups were similar regarding the level of sensory block during sac traction and duration of spinal anesthesia. Duration of spinal analgesia was prolonged significantly in the fentanyl group (P = 0.025). Conclusion: Intrathecal fentanyl at a dose of 0.2 μg·kg⁻¹ added to bupivacaine significantly improves the quality of intraoperative analgesia and prolongs postoperative analgesia in children undergoing inguinal hernia repair with spinal anesthesia.     

A double blind comparison of droperidol and ondansetron for prevention of emesis in children undergoing orthopaedic surgery

Emesis is common in the postoperative period following epidural opioid and general anaesthesia. Eighty patients ages two to 14 years scheduled for major orthopaedic surgery were enrolled in a randomized, double-blind study to compare the prophylactic effects of ondansetron, droperidol and a placebo for the prevention of postoperative emesis. Each child was assigned at random to one of the four treatment groups: ondansetron 100 μg·kg^?1, ondansetron 50 μg·kg^?1, droperidol 60 μg·kg^?1 and saline control. Drugs were administered intravenously after the induction of anaesthesia. Anaesthesia was supplemented with epidural fentanyl, given as an infusion of 1 μg·kg^?1 and continued for postoperative pain control. The incidence of vomiting in the immediate postoperative period was 25% with ondansetron (100 μg·kg^?1), 40% with ondansetron (50 μg·kg^?1) and droperidol and 70% with the control group. In the next 48 h the incidence of emesis increased to 30% for ondansetron (100 μg·kg^?1), 55% with ondansetron (50 μg·kg^?1), 65% with droperidol and 85% for the control group. Those patients who had multiple emesis necessitating a second dose of the same drug treatment showed no difference in the incidence of emesis relative to the control group. Ondansetron (50 μg·kg^?1) and droperidol groups had lower incidence of PONV compared to the control group. The ondansetron (100 μg·kg^?1) group had a significant decrease in the incidence of emesis. We conclude that the prophylactic administration of ondansetron (100 μg·kg^?1) is more effective than droperidol and ondansetron (50 μg·kg^?1) and superior to saline (P<0.02) for the prevention of emesis before epidural opioid and general anaesthesia.     

Oral clonidine premedication decreases energy expenditure in human volunteers

Purpose

Clonidine not only stops postoperative shivering and decreases oxygen consumption, but also decreases energy expenditure with or without a reduction in shivering during recovery from anaesthesia. It is important to see if clonidine decreases energy expenditure at rest since this may contnbute to a postoperative decrease in energy expenditure. The authors tested the hypothesis that oral clonidine decreases energy expenditure at rest.

Methods

Twenty healthy male volunteers were randomly assigned to one of two groups. Ten volunteers received oral clonidine approximately 5 μg·kg^?1 (clonidine group), while the remaining 10 volunteers received placebo (control group). Blood pressure, heart rate, body temperature at the tympanic membrane, sedation score graded from 1 (alert) to 5 (sleeping and difficult to be aroused by tactile stimulation) were measured before and at 30-mm intervals for three hours after administration of clonidine or placebo. Measurements of energy expenditure and respiratory quotient were made with a head canopy system at one-minute intervals and averaged over 15 mm before, and at 30, 60, 90, 120, and 180 min after administration of clonidine or placebo.

Results

Sedation score increased from 1 to 3 (median) after clonidine administration. Energy expenditure decreased from 1452± 225 kcal·24hr (mean± SD) at baseline to 1258 ± 175 kcal·24hr at 180 min after clonidine administration (P < 0 05).

Conclusion

This study suggests that oral clonidine at a dose of 5 μg·kg^?1 decreases energy expenditure at rest.     

The relationship between age and morphine infusion rate in children

Aim: We performed a retrospective audit of intravenous morphine infusion administered to children in an effort to characterize the relationship between dose and age. Methods: A retrospective audit of morphine infusions was reviewed for a 24‐months period and included all children who received continuous intravenous nurse‐controlled morphine infusions and patient‐controlled analgesia; a population undergoing acute and elective surgical procedures, as well as medical and oncological treatments. The relationship between age and infusion rate was investigated using nonlinear mixed effects models. Results: There were 886 children whose data were acceptable for review. Morphine dose increased with age from 9.97 (CV 28%) μg·kg^?1 per h in neonates. The Hill equation with an exponential of 1.5 best described these changes. Morphine rate reached 90% of its mean final rate of 22.5 (CV 167%) μg·kg^?1 per h, observed in teenagers, at approximately 5 years of age. There was considerable uncertainty of this age–morphine rate profile, and the maturation half‐life of this profile was 20 months of age (CV 632%). An increase in dosing variability was observed with increasing age. Conclusions: Morphine infusions at steady‐state did not mirror clearance maturation in children nursed in our hospital. We suggest that initial infusion rates in children are started at 10 μg·kg^?1 per h in neonates, 15 μg·kg^?1 per h in toddlers and 25 μg·kg^?1 per h in children above the age of 5 years. The large variability associated with infusion rates means that subsequent infusion rates will depend on feedback from pain scores, adjuvant medications and adverse effects.     

Midazolam for caudal analgesia in children: comparison with caudal bupivacaine

In a randomized, double-blind study we have examined the analgesic efficacy of caudal administration of midazolam, bupivacaine, or a mixture of both drugs in 45 children, undergoing inguinal herniotomy. They were allocated randomly into three groups (n = 15 in each) to receive a caudal injection of either 0.25% bupivacaine 1 ml · kg^?1 with or without midazolam 50 μg · kg^?1 or midazolam 50 μg · kg^?1 with normal saline 1 ml · kg^?1. There were no differences in quality of pain relief, postoperative behaviour or analgesic requirements between the midazolam group and the other two groups. Times to first analgesic administration (paracetamol suppositories) were longer (P < 0.001) in the bupivacaine-midazolam group than in the other two groups. Further, the bupivacaine-midazolam group received fewer (P < 0.05) doses of paracetamol than the bupivacaine group. Side effects such as motor weakness, respiratory depression or prolonged sedation were not observed in patients who received caudal epidural midazolam only. We conclude that caudal midazolam in a dose of 50 μg · kg^?1 provides equivalent analgesia to bupivacaine 0.25%, when administered postoperatively in a volume of 1 ml · kg^?1 for children following unilateral inguinal hemiotomy.