The aim of this prospective, interventional, randomized trial is to compare the effectiveness of postoperative analgesia using single-dose intrathecal morphine and intravenous morphine in patients undergoing liver resection. The study is to include a total 36 patients randomized in a 1:1 ratio into two groups. The study will be single-blinded with respect to outcome assessors. Patients in the experimental group (n=18) will receive a single dose (0,4 mg) intrathecal morphine immediately before operation and patient-controlled analgesia (PCA) with morphine over first 24 postoperative hours and subcutaneous morphine (5 mg in case of numerical rating scale>4) over next two days in the postoperative period. Patients in the control group (n=18) will receive a single dose of intravenous morphine (0,15 mg/kg body mass) immediately after the operation and PCA with morphine over first 24 postoperative hours and subcutaneous morphine (5 mg in case of numerical rating scale>4) over next two days. Both groups will receive antiemetic prophylaxis with dexamethasone (4 mg) and ondansetron (4 mg) and standard baseline analgesia with paracetamol (1,0 g every 6 hours) and dexketoprofen (50 mg every 8 hours). Severity of pain at rest evaluated with numerical rating scale twice daily over 3 first postoperative days will be the primary outcome measure. Secondary outcome measures will include: severity of pain at coughing evaluated with numerical rating scale twice daily over 3 first postoperative days, total dose of morphine administered with PCA, time to patient mobilization, grade of sedation, intestinal motility, solid food intake tolerance, duration of hospitalization, and postoperative complications.

Effective analgesia in patients undergoing liver resection is an important measure to enhance the process of postoperative recovery. The aim of this prospective, interventional, randomized trial is to compare the effectiveness of postoperative analgesia using single-dose intrathecal morphine and intravenous morphine in patients undergoing liver resection. The study is to include a total 36 patients randomized in a 1:1 ratio into two groups. The patients scheduled for liver resection in the Department of General, Transplant and Liver Surgery (Medical University of Warsaw) will be screened for eligibility basing on inclusion and exclusion criteria. Eligible patients will be included in the study following provision of informed consent. Randomization will be performed immediately before the surgical procedure in the operating theatre. The study will be single-blinded with respect to outcome assessors. Patients in the experimental group (n=18) will receive a single dose (0,4 mg) intrathecal morphine immediately before operation and patient-controlled analgesia (PCA) with morphine over first 24 postoperative hours and subcutaneous morphine (5 mg in case of numerical rating scale>4) over next two days in the postoperative period. Patients in the control group (n=18) will receive a single dose of intravenous morphine (0,15 mg/kg body mass) immediately after the operation and PCA with morphine over first 24 postoperative hours and subcutaneous morphine (5 mg in case of numerical rating scale>4) over next two days. Both groups will receive antiemetic prophylaxis with dexamethasone (4 mg) and ondansetron (4 mg) and standard baseline analgesia with paracetamol (1,0 g every 6 hours) and dexketoprofen (50 mg every 8 hours). Severity of pain at rest evaluated with numerical rating scale twice daily over 3 first postoperative days will be the primary outcome measure. Secondary outcome measures will include: severity of pain at coughing evaluated with numerical rating scale twice daily over 3 first postoperative days, total dose of morphine administered with PCA, time to patient mobilization, grade of sedation, intestinal motility, solid food intake tolerance, duration of hospitalization, and postoperative complications. Side effects of intrathecal morphine injection and intravenous morphine administration will be monitored. The thresholds for type I and type II errors will be set at 0.05 and 0.20, respectively.

Inclusion Criteria:

• liver resection
• liver malignancy

Exclusion Criteria:

• >3 points in American Society of Anesthesiology (ASA) scale
• contra-indications for intrathecal morphine administration
• chronic preoperative intake of analgetics
• a history of opioid dependency
• body mass index >45 kg/m2
• allergy to any analgetic drug administered in the study