ON-Q Pump Infusion of Ketorolac and Ropivacaine at the Wound Site for Postoperative Pain Management

Overview

After surgery it is normal to experience some pain at the site of operation. In order to reduce the pain, medication such as Morphine is injected into a vein using a Patient Controlled Analgesia (PCA) pump that is kept at bed side, and is activated by the patient when needed. However, Morphine is an opioid drug, which can cause side effects such as sedation, nausea, vomiting, and reduced breathing on prolonged use. In addition to the opioid drugs, local anesthetics, and other drugs called Non steroidal anti inflammatory drugs (NSAIDs) have been injected locally to provide prolonged pain relief without the side effects of morphine. Recently a portable device called ON-Q pump has been developed to continuously infuse the local anesthetic through 2 small catheters inserted at the wound site. The ON-Q Pump is a small tennis ball sized unit made of a soft synthetic material that slowly infuses the drug through the catheters by elastic force. This pump is very safe and is attached to a bedside pole or the patient's hospital gown. This pump has already been approved by the FDA for clinical use, and has been reported to provide effective pain management after some surgical procedures. The primary aim of the present study is to evaluate the relative efficacy of the drugs Ketorolac and Ropivacaine infused through the ON-Q pump in reducing the pain following gynecologic surgery. Ketorolac and Ropivacaine are approved drugs that are frequently used for post operative pain relief. Our hypothesis is that these two drugs in combination will provide better analgesia than Ketorolac alone.

This study would include a total of 60 patients randomized into 2 equal groups. Patients will be interviewed in the holding area and informed signed consent will be obtained. Patients will be induced with general anesthesia in keeping with standard practice. At the end of surgical procedure, before the patient is extubated, the Surgeon will secure the 2 catheters of the ON-Q pump at two levels of the fascia near the incision site. First the surgeon will instill at the wound site a bolus dose of 30 ml of 0.9% saline with 10 mg Ketorolac in Group I, or 30 ml of saline with 0.5% Ropivacaine and 10 mg Ketorolac in Group II patients. Then the continuous infusion with the ON-Q pump will be started at 4 ml/hr, and Group I patients will receive saline with Ketorolac at 5 mg/hr not to exceed 120 mg per day, and Group II will receive saline with 0.5% Ropivacaine plus Ketorolac at 5 mg/hr. Patients will be extubated, as per standard anesthetic practice. All patients will receive anti ulcer medication. On arrival at the Post Anesthesia Care Unit (PACU), the patient will receive an i.v. PCA pump, which will administer Morphine Sulfate 2 mg in incremental doses on demand by the patient. A blinded investigator will collect the study data from each patient at 6, 12, 24, and 48 hrs postoperative periods. The data collected would include 1) Visual Analog Scale (VAS) scores for pain at rest, on coughing and on moving, 2) PCA demands by the patient and actual deliveries of morphine, 3) "rescue" analgesic requirements (for pain score of 4 or greater). 4) VAS scores for Nausea, drowsiness, and satisfaction, and 5) number of vomiting.