Abstract ID: A18
Abstract Title: Continuous Popliteal Sciatic Nerve Block at Home: Postoperative Analgesia Optimization Using Three Modes of Local Anesthetic Delivery
Poster Type: Discussion
ABSTRACT BODY
Introduction: A continuous popliteal sciatic nerve block with a local anesthetic infusion via a perineural catheter decreases pain, opioid use and opioid-related side effects, sleep disturbances, and improves overall satisfaction (1). Previous investigations of interscalene (2), axillary (3), fascia iliaca (4), extended femoral (5), and subgluteal (6) catheters have demonstrated that the optimal infusion method varies with anatomic location. This randomized, double-blinded study compared continuous and patient-controlled ropivacaine infusions via a sciatic perineural catheter in the popliteal fossa for ambulatory patients undergoing moderately painful orthopedic surgery of the foot.
Methods: Preoperatively, following IRB approval and informed consent, all patients had a sciatic perineural catheter placed at the apex of the popliteal fossa. After a nerve stimulator and 8.9 cm, 17 g insulated needle (StimuCathTM, Arrow International, Reading, PA) were used to illicit foot plantar-flexion at 0.3-0.5 mA, a perineural stimulating catheter was advanced 3-5 cm beyond the needle tip. Following negative aspiration, 50 mL of anesthetic solution was injected via the in divided doses. The injectate contained mepivacaine, 1.5%; epinephrine, 125 µg; and clonidine, 100 µg. Postoperatively, patients were discharged home with a portable, electronic infusion pump (CADD-Legacy, Deltec, St. Paul, MN). Postoperative infusion consisted of ropivacaine 0.2% (500 mL) and was delivered in one of 3 regimens determined in a randomized, double-blinded fashion: a basal rate of 12 mL/h and patient-controlled bolus of 0.05 mL (BASAL group, n=7); an 8 mL/h basal and 4 mL bolus (BASAL/BOLUS group, n=9); or a 0.3 mL/h basal and 9.9 mL bolus (BOLUS group, n=7). All bolus functions had a 60 min lock-out period. All patients received a prescription for oxycodone 5 mg / acetaminophen 500 mg tablets. A physician was available by telephone at all times. Patients were contacted by telephone post-operative days (POD) 0-4. On the evening of POD 3, or when the anesthetic reservoir was empty, whichever came first, patients’ caretakers removed the catheters with instructions given over the telephone. P-values were determined by one- or two-way ANOVA or Chi Square.
Results: There were no statistically significant differences among the groups in respect to demographic or surgical endpoints. For Figures 1-3, data are expressed as median (25th – 75th confidence intervals) with the exception of Fig 3, Panel A, in which data are expressed as the fraction of patients reporting difficulty sleeping because of pain. P<0.05 for group comparisons for a given POD: † BASAL/BOLUS vs. BOLUS; * BOLUS vs. BASAL; and ‡ BASAL/BOLUS vs. BASAL.
Conclusion: Following moderately painful orthopedic surgery of the foot, ropivacaine delivered via a sciatic popliteal perineural catheter as a continuous infusion combined with patient-controlled bolus doses provided optimal analgesia while minimizing opioid use and sleep disturbances.
References: (1) Anesthesiology 2002; 97: 959-65. (2) Anesth Analg 1999; 89:1216-20. (3) Ann Fr Anesth Reanim 1998; 17: 1099-103. (4) Reg Anesth Pain Med 2002; 27: 604-11. (5) Anesth Analg 2001; 92: 455-9. (6) Reg Anesth Pain Med 2002; 27: 168-72.
ATTACHED FILES
A18_Figure 1, popliteal abstract.ppt
A18_Figure 2, popliteal abstract.ppt
A18_Figure 3, popliteal abstract.ppt
Reg Anesth Pain Med 2004; 29(2):A18