title: Continuous wound infiltration with ropivacaine reduces pain and analgesic requirement after shoulder surgery.
abstract: After achieving a reduction of pain scores for 10 h with a single dose wound infiltration after shoulder surgery, we examined in a prospective, placebo-controlled and double-blinded study the analgesic effects of continuous wound infiltration with different concentrations of ropivacaine. Forty-five patients undergoing shoulder surgery were randomly assigned into three groups to receive single dose wound infiltration with 30 mL saline (group S) or ropivacaine 7.5 mg/mL (groups R2 and R3.75) after skin closure. Postoperatively, patients received a continuous wound infiltration with saline (group S), ropivacaine 2 mg/mL (group R2) or ropivacaine 3.75 mg/mL (group R3.75) for 48 h. Supplemental pain relief was provided by IV patient-controlled analgesia with the opioid piritramide. At 1, 2, 3, 4, 24, and 48 h postoperatively visual analogue scale (VAS) values (0-100 mm), piritramide requirements and side effects were registered. Plasma levels of ropivacaine were measured preoperatively and at 24 h and 48 h after surgery. Until 48 h VAS values were smaller in group R3.75 compared with group S (group R3.75, 8 +/- 9 mm; group S, 31 +/- 14 mm; P < 0.005), whereas 4 h and 48 h postoperatively VAS values were even smaller in group R3.75 compared with group R2 (P < 0.05). Cumulative piritramide consumption was always smaller in groups R2 and R3.75 compared with group S (1-24 h, P < 0.005; 48 h, P < 0.05). Plasma ropivacaine levels remained less than the toxic threshold. We conclude that continuous postoperative wound infiltration with ropivacaine, especially using 3.75 mg/mL, provides smaller VAS values and opioid requirement in comparison with saline after shoulder surgery.
  
  
  CONCLUSIONS
  The continuous postoperative wound infiltration after shoulder surgery with different concentrations of ropivacaine, 2 mg/mL and 3.75 mg/mL, results in lower pain scores and opioid requirement compared with infiltration with placebo. Plasma levels of ropivacaine remained less than the toxic threshold.
mesh_terms: D000328:Adult; D000577:Amides / Q000008:administration & dosage / Q000493:pharmacokinetics / Q000627:therapeutic use*; D000701:Analgesics, Opioid / Q000008:administration & dosage / Q000627:therapeutic use*; D000772:Anesthesia, Local; D000779:Anesthetics, Local / Q000008:administration & dosage / Q000493:pharmacokinetics / Q000627:therapeutic use*; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010147:Pain Measurement; D010149:Postoperative Pain / Q000453:epidemiology / Q000517:prevention & control*; D010892:Pirinitramide / Q000008:administration & dosage / Q000627:therapeutic use; D011183:Postoperative Complications / Q000453:epidemiology; D020250:Postoperative Nausea and Vomiting / Q000453:epidemiology; D011446:Prospective Studies; D000077212:Ropivacaine; D012782:Shoulder / Q000601:surgery*
chemical_list: D000577:Amides; D000701:Analgesics, Opioid; D000779:Anesthetics, Local; D010892:Pirinitramide; D000077212:Ropivacaine