Local Anesthesia Versus Saline Serum in Surgical Incision of Colorectal or Hepatic Surgery

Postoperative analgesia in major abdominal surgery is managed with intravenous PCA (patient controlled analgesia) with morphine associated to non-steroidal anti-inflammatories drugs (NSAD) and paracetamol in the first 48 hours of the postoperative phase. With this multimodal approach patients undergoing colorectal surgery have a median pain score on the verbal scale (0-10) of 3 (range 0-8) with a mean of morphine consumption of 54 mg (SD 24 mg) and patients undergoing hepatic surgery have a median pain score of 2(range 0-7) with a mean of morphine consumption of 28 mg (SD 17 mg).

Although opiates are very potent analgesics they also produce side effects and numerous studies have demonstrated a significant reduction in morbidity when patients received lower dose of opiates during anesthesia and in postoperative period. Continuous infusion of local anesthetics in the surgical wound has been used for pain control in different types of surgeries. However, controversial reports has been reported in abdominal surgery.

We are conducting prospective, randomised and double-blind placebo control trials in two surgical models (colo-rectal oncologic surgery and hepatic resection) using continuous perfusion of ropivacaine 0.38% in the surgical wound versus saline.

Anesthetic protocol is the same for all patients.

Patients undergoing colo-rectal surgery can be operated either in laparotomy or laparoscopic technique therefore patients are stratified into four groups once surgical closure has begun:

• Group A1 ropivacaine and laparotomy
• Group A2 ropivacaine and laparoscopy
• Group B1 saline and laparotomy
• Group B2 saline and laparoscopy

In the preanesthesia visit patients who match inclusion criteria are invited to participate in the study and they signed the informed consent. When the patient is in the theatre a nurse not involved in the management of patients opens a closed envelope which indicates the solution to be prepared according to the assigned group.

The surgeon inserts a multiperforated catheter at the subfascial level of surgical wound , just below the suture of the muscular fascia (between the peritoneum and the muscular fascia) and after that surgeons finish the subcutaneous plane and the skin. After the closure a bolus of 5 ml (laparoscopy colon surgery)or 10 ml (laparotomy colon and hepatic surgery) of the solution is given through the catheter and subsequently an elastomer filled with ropivacaine or saline is connected. The catheter is fixed to the skin with steri-strip and sterile dressing.

During the procedure we administer in a protocol basis the NSAD and thirty minutes before the end of the surgery we administer morphine. In the postoperative period the patient receives a NSAD regime and a PCA morphine treatment.

The catheter is withdrawn after 48 hours and also the PCA and the analgesic treatment is with NSAD.

Inclusion criteria

• ASA I-III
• Undergoing scheduled colorectal cancer and hepatic surgery
• Patients must be able to understand the PCA (the self administration system)

Exclusion criteria

• Background of allergic reaction or contraindication for local anesthesia or non steroid anti-inflammatory drugs.
• Patient with epidural catheter or receiving combined analgesia during surgery (age above 80, moderate-severe respiratory dysfunction, patients who prior presented complex postoperative pain management.
• Emergency surgery
• Patients with risk of hepatic insufficiency (Klatskin's tumor, extended right hepatectomy, right hepatectomy in patients with steatosis, hepatic resection in patients over 70 years of age who have been given chemotherapy).
• Inflammatory bowel disease: ulcerative colitis, Crohn's disease.
• Major psychiatric condition.
• Patients with active drug addiction or on chronic treatment with opiates.
• Morbid obesity (BMI > 35 kg/m2)
• Patients with heart disease (myocardiopathy, conduction alterations, antiarrhythmic treatment) and severe liver disease (alteration synthesis, histolysis and or cholestasis).
• Patients with kidney failure.
• Patients treated with fluvoxamine (antidepressant) and enoxacin (antibiotic) both are potent inhibitors of CYPIA2.
• Septic patients
• Patients that do not wish to participate.