Comparison of intrapleural versus intravenous morphine for postthoracotomy pain management

To compare the analgesic effects of intrapleural and intravenous morphine administration for postthoracotomy pain management. Randomized, prospective trial. University teaching hospital. Twenty-eight consenting patients scheduled for elective thoracotomy operations. Patients were randomly allocated into two groups to receive either 20 mg of intrapleural morphine (IPM group) or 20 mg of intravenous morphine (IVM group) at the end of the operation. Plasma morphine levels, arterial pressures, heart rate, verbal analog scale (VAS), respiratory rate, and PaCO 2 levels were compared in two groups. Plasma morphine levels were significantly higher in the IVM group at the 5th minute until the 2nd postoperative hour. VAS was significantly higher in the IVM group. Respiratory rates were significantly higher in the IPM group, whereas PaCO 2 remained significantly lower than in the IVM group. IPM achieved better analgesia than IVM and this effect is probably attributable to peripheral effects of morphine.