Anesth Analg 2003;97:1608-1611
© 2003 International Anesthesia Research Society
PEDIATRIC ANESTHESIA
Patient-Controlled Epidural Analgesia Versus Continuous Epidural Infusion with Ropivacaine for Postoperative Analgesia in Children
Emmanuel Antok, MD*,
Fabienne Bordet, MD*,
Frédéric Duflo, MD*,
Sabine Lansiaux, MD*,
Sylvie Combet, MD*,
Patricia Taylor, MD*,
Agnes Pouyau, MD*,
Brigitte Paturel, MD*,
Robert James, MS
,
Bernard Allaouchiche, MD PhD*, and
Dominique Chassard, MD PhD*
*Service d’Anesthésie-Réanimation, Hôpital de l’Hôtel-Dieu et Debrousse, Lyon, France; and
Department of Anesthesiology, Bowman Gray School of Medicine, Wake Forest University, Winston-Salem, North Carolina
Address correspondence and reprint requests to Dominique Chassard, MD, PhD, Service d’Anesthésie-Réanimation, Hôpital de l’Hôtel-Dieu, 69002, Lyon, France. Address e-mail to dominique.chassard{at}chu-lyon.fr
 |
Abstract
|
|---|
Epidural ropivacaine infusion has been used in children; however, patient-controlled epidural analgesia (PCEA) has not been evaluated in the pediatric population. In this study, we compared the clinical efficiency of PCEA and of continuous epidural infusion analgesia (CEA) in children. Forty-eight children undergoing orthopedic surgery were randomized to receive PCEA or CEA with ropivacaine 0.2%. All patients underwent a standard general anesthetic. Children also received ketoprofen and propacetamol. Pain scores and side effects were recorded for 48 h. If the visual analog score scale score was >4 of 10, analgesia was considered inadequate, and rescue treatment was administered. Both groups obtained effective pain relief. Children in the PCEA group received significantly less local anesthetic than those in the CEA group (0.20 ± 0.08 mg · kg-1 · h-1 versus 0.40 ± 0.08 mg · kg-1 · h-1; P < 0.001). Motor effects, supplemental analgesic requirements, and side effects did not differ. We concluded that PCEA with ropivacaine 0.2% can provide adequate postoperative analgesia for pediatric orthopedic procedures with smaller dose requirements than CEA.
IMPLICATIONS: We studied patient-controlled epidural analgesia (PCEA) and continuous epidural infusion analgesia (CEA) with 0.2% ropivacaine during the postoperative period in children. We found that either PCEA or CEA with plain ropivacaine 0.2% provided adequate pain relief in children during the first 48-h postoperative course. However, adequate analgesia was obtained with 50% less volume infused with PCEA compared with CEA.
|
Introduction
|
|---|
Epidural analgesia for postoperative analgesia in children is often managed by continuous epidural infusion of local anesthetic (CEA) (1,2). However, the goal of any epidural analgesic technique is to achieve adequate analgesia with minimal local anesthetic to decrease all side effects associated with a local anesthetic. In adults, patient-controlled epidural anesthesia (PCEA) offers the possibility for optimal analgesia with a smaller amount of local anesthetics than during CEA (3). The concept of PCEA with local anesthetics has not been evaluated in children. We prospectively studied CEA and PCEA by using ropivacaine 0.2% in children.
|
Methods
|
|---|
After institutional approval, we studied children aged 7–12 yr. Children were scheduled for lower extremity orthopedic procedures lasting for >30 min that required major analgesia (osteotomy of large bone, arthrotomy, and cyst or tumor resection). Patients were visited before their operation and taught to use the trigger of the PCEA machine (Abbott Pain Manager; Abbott Laboratories, Chicago, IL) during the visit. After informed patient consent and written parental consent were obtained, the patients were randomized by a number table to receive PCEA or CEA with ropivacaine 0.2% during the postoperative period. Exclusion criteria were ASA status >III, younger than 7 yr of age or older than 13 yr, neuromuscular disease, back problems, skin infection of the lumbar area, coagulation disorder, allergy to local anesthetics, inability to quantify pain on a visual analog scale (VAS), or inability to use the PCEA device during the preoperative visit.
Premedication consisted of midazolam 0.2 mg/kg by mouth or intrarectal midazolam 0.3 mg/kg given approximately 30 min before anesthesia. General anesthesia was induced with sevoflurane delivered in 100% oxygen. Once the child was anesthetized, an IV catheter was inserted, and lactated Ringer’s solution was infused at 10 mL · kg-1 · h-1. Anesthesia was maintained by remifentanil infused at 1 µg/kg during 1 min. The airway was maintained with a laryngeal mask or an orotracheal tube. Anesthesia was maintained with sevoflurane 1.5%–2% in 50% nitrous oxide in oxygen and remifentanil at a rate of 25 µg · kg-1 · h-1 until the end of the surgery.
Before the surgical procedure began, the patients were placed in the lateral position, and, under sterile conditions, an epidural catheter was inserted at the L3-4 or L4-5 interspace level by using a Tuohy 18-gauge needle and a loss-of-resistance technique with normal saline. After placement of the catheter, a test dose of lidocaine 1% with epinephrine 1:200,000 was administered.
Thirty minutes before the end of the surgical procedure, 10 mL of ropivacaine 0.2% was administered through the epidural catheter. At the end of surgery, the patient was tracheally extubated and transferred to the postanesthesia care unit. Patients allocated to the PCEA group received bolus doses of ropivacaine 0.2% 2 mL with a lockout interval of 10 min and a background infusion rate of 1.6 mL/h. Patients allocated to the CEA group received a continuous infusion of 0.4 mg · kg-1 · h-1 of ropivacaine 0.2%. Patients in the PCEA group were able to titrate their ropivacaine requirements from a minimum of 1.6 mL/h (3.2 mg) to a maximum of 13.6 mL/h (27.2 mg). After a brief observation period in the postanesthesia care unit, patients were then returned to their regular ward, and the epidural infusion was continued for 48 h.
During the 48-h study period, the quality of pain analgesia was assessed by using a VAS. Children were not awakened from sleep for assessment, and "asleep" was recorded on the chart at these times. The degree of motor block in the lower extremities was recorded with a modified Bromage scale (score: 0 = no movement; 1 = ankle only; 2 = ankle and knee; 3 = ankle, knee, and hip). Pain scores (0–10), motor block score, noninvasive arterial blood pressure, and other side effects (urinary retention, nausea, and vomiting) were recorded every 4 h for 48 h by an independent observer. The volume of ropivacaine infused was recorded hourly. Sensory level was evaluated by pinprick test twice a day. All patients received propacetamol 30 mg/kg and ketoprofen 1 mg/kg IV every 6 h. Supplemental analgesia (nalbuphine 0.2 mg/kg IV) was given if patients in either group complained of inadequate analgesia despite activating the demand button. At the end of the 48-h postoperative period, the total consumption of ropivacaine was noted. Specific problems, such as epidural catheter-related problems (disconnection, leakage, and local inflammation), were also recorded.
The proposed sample size was 18 for each group, and the study was powered to 90% to yield a statistically significant result. This computation assumes that the mean difference is 20% (corresponding to means of 0.440 versus 0.352 mg · kg-1 · h-1 of ropivacaine dosage) and that the common within-group standard deviation (SD) is 0.078. This effect was selected as the smallest effect that would be important to detect, in the sense that any smaller effect would not be of clinical or substantive significance. Data are presented as means and SD. For all statistical analyses, the StatView computer software package was used (SAS Institute, Cary, NC). Differences between groups were analyzed with a repeated-measures analysis of variance (two-way analysis of variance with repeated measures) or 
2 tests, as appropriate. The significance level was set at 0.05.
|
Results
|
|---|
Forty-eight children were studied, and all patients underwent successful epidural placement. Demographic data are given in Table 1. The two groups did not differ in age, weight, height, or sex. Both groups obtained effective pain relief (Fig. 1), with an average VAS value of 1.04 for the PCEA group and of 0.78 for the CEA group during the first 24 h (P = not significant). During the second day, the average VAS scores were 0.82 ± 0.28 and 0.76 ± 0.2, respectively (P = not significant). One patient in the PCEA group and three in the CEA group received supplemental analgesia.
View larger version (20K):
[in this window]
[in a new window]
|
Figure 1. Mean (SD) 4-hourly total pain scores in the patient-controlled epidural analgesia (PCEA) and continuous epidural infusion analgesia (CEA) groups; SD values are shown on top of the bars (black bars, CEA; white bars, PCEA). VAS = visual analog scale score (in mm [0 to 100]).
|
|
Patients in the PCEA group received half the hourly local anesthetic compared with those in the CEA group (0.20 ± 0.08 mg · kg-1 · h-1 versus 0.40 ± 0.08 mg · kg-1 · h-1; P < 0.001). There was no difference in the average hourly dose of ropivacaine between the first and second day (0.199 mg · kg-1 · h-1 versus 0.200 mg · kg-1 · h-1) in the PCEA group. The total dose of ropivacaine was 239 mg/48 h for the PCEA group versus 576 mg/48 h for the CEA group (P < 0.001).
There were no statistical differences between the two groups with respect to side effects. The incidence of nausea and vomiting was 1 in 24 in the PCEA group versus 2 in 24 in the CEA group. Concerning urinary retention, it was present in one patient in the PCEA group and three patients in the CEA group. No block height was above T10.
|
Discussion
|
|---|
The findings of our study demonstrated that either PCEA or CEA with plain ropivacaine 0.2% provided no difference in analgesia in children during the first 48 hours after surgery, as evidenced by no difference in pain scores or analgesic supplemental requirements. However, PCEA provided less total ropivacaine than CEA.
On the basis of previous studies, the dosage regimen used in our CEA group was set at 0.4 mg · kg-1 · h-1. This dose regimen has been successfully used for postoperative analgesia in children by the caudal route (4–6). Hansen et al. (7) showed that CEA of 0.4 mg · kg-1 · h-1 provided good analgesia with few side effects. Total and free ropivacaine concentrations with this dose regimen were within the range reported to be "safe" in previous studies in adults (100–3189 µg/L and 10–56 µg/L respectively) (8).
There are no studies on the use of PCEA with ropivacaine 0.2% for postoperative analgesia in children. We chose ropivacaine because it has the potential to produce differential neural blockade with less motor block and less systemic toxicity than bupivacaine (9). Ropivacaine 0.2% has been used in younger children, and several studies have reported its clinical efficacy and safety when administered for caudal epidural anesthesia and as a CEA for postoperative analgesia (4–7). We did not observe significant motor block, as assessed by the Bromage score, in this study. However, all patients underwent orthopedic procedures on the lower limbs and could not walk in the first 48 postoperative hours; the preservation of motor function is a less important element in orthopedic surgery.
Our study demonstrates that the PCEA method is effective for pain relief and is safe over 48 hours. In an elderly population, PCEA showed several advantages over patient controlled-analgesia (PCA), particularly concerning the side effects associated with systemic opioids (10). Thus, compared with morphine PCA, PCEA with a local anesthetic may also result in fewer opioid toxicity reactions in a pediatric population. Concerning the side effects, there were no differences between our two groups.
PCEA provided similar analgesia to CEA with a smaller dose of ropivacaine. A major finding of our study is that analgesia with PCEA was obtained at half the dose of ropivacaine. The hourly dose requirement for ropivacaine 0.2% has also been reported to be smaller during PCEA than during CEA (11). The differences in the sparing effect observed with PCEA among previous studies are probably linked to the amount of the background infusion during PCEA and to the solution used for the PCEA method. PCEA may help to reduce local anesthetic doses by adjusting analgesia.
We chose a PCEA method that used a bolus injection plus a continuous, fixed-rate infusion because this method has shown that the use of PCA with morphine with background infusion is associated with a better sleep pattern than PCA without background infusion (12). In adults, the effect of the use of a background infusion rate during PCEA is still controversial. A decrease of the physician-administered supplemental bupivacaine dose has been reported by Ferrante et al. (13). But a background infusion in PCEA with sufentanil does not offer major advantages in terms of sleep quality or sufentanil consumption (14). Side effects may be more pronounced because of increased drug administration. Thus, further studies are required before a background infusion rate during PCEA in children is recommended.
The demand to delivery ratio (D/D ratio) has been used as an indirect indicator of pain relief during PCA or PCEA. Adequate analgesia is usually provided with a D/D ratio less than 2 (15). This study reported a mean D/D ratio of 3.11 for the first day and 2.9 for the second day. However, we observed that two children pressed the demand button because of anxiety while their VAS scores were <3. When these two patients were omitted, the D/D ratio was of 2.34 and 1.43 at Day 1 and Day 2, respectively. Thus, the D/D ratio must be used with caution for analyzing the efficacy of PCEA in children.
In summary, this study suggests that the use of PCEA with lumbar epidural placement for postoperative analgesia after orthopedic surgery has an analgesic-sparing effect in children. The PCEA is an attractive method for postoperative pain treatment in children, and various dose regimens may be developed for this purpose.
|
References
|
|---|
- Ecoffey C, Dubousset AM, Samii K. Lumbar and thoracic epidural anesthesia for urologic and upper abdominal surgery in infants and children. Anesthesiology 1986; 65: 87–90.[ISI][Medline]
- Murat I, Delleur MM, Esteve C, et al. Continuous extradural anesthesia in children. Br J Anaesth 1987; 69: 1441–50.
- Gambling DR, Yu P, Cole C, et al. A comparative study of patient controlled epidural analgesia (PCEA) and continuous infusion epidural analgesia (CIEA) during labour. Can J Anaesth 1988; 35: 249–54.[Abstract/Free Full Text]
- Moriaty A. A use of ropivacaine in postoperative infusions [letter]. Paediatr Anaesth 1997; 7: 478.[ISI][Medline]
- Ivani G, Lampugnani E, De Negri P, et al. Ropivacaine vs bupivacaine in major surgery in infants. Can J Anaesth 1999; 46: 467–9.[Abstract/Free Full Text]
- Ivani G, Mereto N, Lampugnani E, et al. Ropivacaine in paediatric surgery: preliminary results. Paediatr Anaesth 1998; 8: 127–9.[ISI][Medline]
- Hansen TG, Ilett KF, Lim SI, et al. Pharmacokinetics and clinical efficacy of long-term epidural ropivacaine infusion in children. Br J Anaesth 2000; 85: 347–53.[Abstract/Free Full Text]
- Erichsen CJ, Sjövall J, Kehlet H, et al. Pharmacokinetics and analgesic effects of ropivacaine during continuous epidural infusion for postoperative pain relief. Anesthesiology 1996; 84: 834–42.[ISI][Medline]
- Scott DA, Chamley DM, Mooney PH, et al. Epidural ropivacaine infusion for postoperative analgesia after major lower abdominal surgery: a dose finding study. Anesth Analg 1995; 81: 982–6.[Abstract]
- Mann C, Pouzeratte Y, Boccara G, et al. Comparison of intravenous or epidural patient-controlled analgesia in the elderly after major abdominal surgery. Anesthesiology 2000; 92: 433–41.[ISI][Medline]
- Sia AT, Chong JL. Epidural 0.2% ropivacaine for labour analgesia: parturient-controlled or continuous infusion? Anaesth Intensive Care 1999; 27: 154–8.[ISI][Medline]
- Doyle E, Robinson D, Morton S. Comparison of patient-controlled analgesia with and without a background infusion after lower abdominal surgery in children. Br J Anaesth 1993; 71: 670–3.[Abstract/Free Full Text]
- Ferrante FM, Rosinia FA, Gordon C, Datta S. The role of continuous background infusions in patient-controlled epidural analgesia for labor and delivery. Anesth Analg 1994; 79: 80–4.[Abstract/Free Full Text]
- Vercauteren MP, Coppejans HC, ten Broecke PW, et al. Epidural sufentanil for postoperative patient-controlled analgesia (PCA) with or without background infusion: a double-blind comparison. Anesth Analg 1995; 80: 76–80.[Abstract]
- Ginsberg B, Gil KM, Muir M, et al. The influence of lockout intervals and drug selection on patient-controlled analgesia following gynecological surgery. Pain 1995; 62: 95–100.[ISI][Medline]
Accepted for publication July 10, 2003.
Top
Abstract
Introduction
