Parietal analgesia decreases postoperative diaphragm dysfunction induced by abdominal surgery: a physiologic study.

BACKGROUND AND OBJECTIVES: The postoperative analgesic strategy may influence the magnitude of the postoperative diaphragmatic dysfunction (PODD) induced by abdominal surgery. The purpose of this physiologic study was to evaluate the effect of continuous preperitoneal wound infusion (CPWI) of ropivacaine on PODD after open colorectal surgery. METHODS: Twenty patients with American Society of Anesthesiologists physical status I or II undergoing open colorectal surgery were prospectively included during 2 consecutive 2-month periods. During the first period, we evaluated 10 consecutive patients who received conventional parenteral analgesia (intravenously administered morphine via patient-controlled analgesia and acetaminophen) without parietal analgesia (control group). These patients were compared with 10 consecutive patients who received conventional parenteral analgesia along with parietal analgesia using CPWI of 0.2% ropivacaine at 10 mL/hr for 48 hrs (CPWI group). Diaphragmatic function was assessed preoperatively and at 24 and 48 hrs postoperatively using the sniff nasal inspiratory pressure test (Psniff). Supplemental intravenously administered morphine boluses were administered as needed before Psniff assessments in the control group to reduce differences in pain intensity. RESULTS: Demographic and surgical data did not differ between the 2 groups, nor did preoperative Psniff values (71 cm H2O [SD, 20 cm H2O] vs 65 cm H2O [SD,15 cm H2O] in the control and CPWI groups, respectively). Postoperative Psniff was significantly decreased in the 2 groups, but the reduction was significantly greater in the control group than in the CPWI group both at 24 hrs (-58% [SD, 18%] vs -24% [SD, 19%]; P = 0.001) and at 48 hrs (-44% [SD, 31%] vs -11% [SD, 32%]; P = 0.027). CONCLUSIONS: Parietal analgesia delivered via a CPWI of ropivacaine reduces PODD induced by open colorectal surgery.

Continuous preperitoneal infusion of ropivacaine provides effective analgesia and accelerates recovery after colorectal surgery: a randomized, double-blind, placebo-controlled study.

BACKGROUND: Blockade of parietal nociceptive afferents by the use of continuous wound infiltration with local anesthetics may be beneficial in a multimodal approach to postoperative pain management after major surgery. The role of continuous preperitoneal infusion of ropivacaine for pain relief and postoperative recovery after open colorectal resections was evaluated in a randomized, double-blinded, placebo-controlled trial. METHODS: After obtaining written informed consents, a multiholed wound catheter was placed by the surgeon in the preperitoneal space at the end of surgery in patients scheduled to undergo elective open colorectal resection by midline incision. They were thereafter randomly assigned to receive through the catheter either 0.2% ropivacaine (10-ml bolus followed by an infusion of 10 ml/h during 48 h) or the same protocol with 0.9% NaCl. In addition, all patients received patient-controlled intravenous morphine analgesia. RESULTS: Twenty-one patients were evaluated in each group. Compared with preperitoneal saline, ropivacaine infusion reduced morphine consumption during the first 72 h and improved pain relief at rest during 12 h and while coughing during 48 h. Sleep quality was also better during the first two postoperative nights. Time to recovery of bowel function (74 +/- 19 vs. 105 +/- 54 h; P = 0.02) and duration of hospital stay (115 +/- 25 vs. 147 +/- 53 h; P = 0.02) were significantly reduced in the ropivacaine group. Ropivacaine plasma concentrations remained below the level of toxicity. No side effects were observed. CONCLUSIONS: Continuous preperitoneal administration of 0.2% ropivacaine at 10 ml/h during 48 h after open colorectal resection reduced morphine consumption, improved pain relief, and accelerated postoperative recovery.