quadratus lumborum block versus transversus abdominis plane block in patients undergoing left hemicolectomy

Conditions: Colon Neoplasm; Surgery; Pain, Postoperative

Summary: the enhanced recovery after surgery and laparoscopic approach have been proven beneficial in surgery of the colon. however, patients have still pain, nausea and vomiting postoperatively. postoperative pain is an expected but undesirable effect after an operation. this study will compare transabdominis plane (tap) block and quadratus lumborum (ql) block with the common postoperative treatment with enteral and parenteral analgesics.

tap is a recommended multimodal method of reducing postoperative pain in laparoscopic and open surgery. tap block seems to be feasible and effective in postoperative pain control without increasing morbidity in colon resections. ql block is also performed as one of the perioperative pain management procedures in abdominal surgery. it is regarded as an effective analgesic tool. the dermatomal effects of ql block reach higher than the tap block, and might explain the better effect of the ql block than tap blocks on postoperative pain after caesarean delivery. for this study the investigators standardize the type of surgery to be left hemicolectomy. this is the most common procedure on colon. power and sample size calculator: the number of patients required for the study was calculated on the basis of opioid consumption. we were interested in a reduction by 20% in the group given qlb. assuming α=0,05, we calculated that we need 69 patients (23 in each group) to achieve a power of 80% (β=0.2). 75 adult patients scheduled for left hemicolectomy have to be included. subcutaneous wound infiltration at the end of surgery in all patients with ropivacaine 2 mg/ml, 20 ml. maximum allowed dosis of ropivacain is 3 mg/kg bodyweight (bw), dosis reduction if bw\<70 kg premedication: paracetamol 2 g and diklofenak 100 mg orally. general anaesthesia: tci: propofol and remifentanil ondansetron 4 mg, dexamethasone 8 mg and oxycodone 5 mg intravenously at the end of surgery. postoperatively: oral paracetamol and codeine-fixed combination up to 1000 mg and 60 mg, respectively, every 6 h in case of insufficient analgesia, as judged by the patient, oxycodon 2 - 5 mg iv. when nausea and vomiting occure postoperatively, ondansetron 4 mg iv administers as the drug of first choice followed by droperidol 0,625 mg iv if the nausea/vomiting persists. collected data: postoperative pain at rest and during activity evaluated by a 4-points verbal pain score (vps; with no pain=0, slight pain = 1, moderate pain = 2, and severe pain = 3) on admission to recovery, and every hour until discharge. rescue analgesic consumption during 0 to 4, 4 to 24 and 24 to 48 h. sedation, nausea and vomiting record by the same 0 - 3 scale (none, slight, moderate, strong) during recovery time of postoperative mobilization with corresponding pain score. time of discharge-to-home or ward readiness according to standard criteria, including stable vital signs, no bleeding from the surgical site, ability to void, absence of excessive nausea and pain, and ability to dress and walk without support. side effects including nausea and/or vomiting (0 to 4, 4 to 24, and 24 to 48 h), antiemetics administered (0 to 24 and 24 to 48 h), grade of sedation (0 to 10 scale, where 0 = awake, and 10 = aroused on stimulation), and other side effects and symptoms of la toxicity. telephone interview at 24 h, 48 h and 7 days, with questions: pain during rest and activity using the vps total need of analgesics sedation nausea level of activity overall satisfaction with the per- and postoperative period on a 0 - 3 scale: not satisfied, slight, moderate or highly satisfied.

Eligibility criteria:
inclusion criteria: * age 18-80 years * bmi 20-35 * asa physical status i-ii exclusion criteria: * allergy to la * chronic pain requiring opioid analgesics * patients with atrioventricular block ii * patients treated with class iii antiarrhythmics * patients with severe renal and/or hepatic disease * a coagulation disorder * an infection at the la injection place