Tramadol for postoperative analgesia in intracranial surgery. Its effect on ICP and CPP

An ideal analgesic for patients after craniotomy should neither cause respiratory depression, nor affect intracranial pressure (ICP) and cerebral perfusion pressure (CPP). The aim of the study was to evaluate the effect of Tramadol (T) on ICP and CPP, as well as to determine its analgetic efficacy in patients (pts) after craniotomy. Thirty five pts aged 16 divided by 78 years (mean 46) entered the study. Twelve had GCS (Glasgow Coma Scale) scores < or = 8 and 23 pts had scores > or = 12. Fourteen pts were mechanically ventilated and 21 pts were breathing spontaneously (BS). Tramadol was injected i.v. at a dose of 0.75 mg/kg over 3 minutes in 11 pts (Group 1), 1.0 mg/kg over 5 minutes in 13 pts (Group 2) and 1.0 mg/kg over 10 minutes in 11 pts (Group 3) PaCO2 was measured before T in all pts and at 8 minute after injection in 21 BS pts. Heart rate (HR), mean arterial blood pressure (MBP), ICP, CPP and respiratory frequency (f) were registered before and in the 1st, 3rd, 8th, and 15th minute after T. Analgetic effect was evaluated in 22 conscious pts by comparing the pain intensity before and 30 minutes after T using a five-point verbal response scale. Mean control ICP was 17 mmHg. ICP over 15 mmHg was diagnosed in 15 pts (mean ICP equal 26 mmHg). Mean CPP for all 35 pts was 85 mmHg. There were no statistically significant changes in HR, MBP, ICP, and CPP after T in any particular group, nor were there changes in ICP in subgroups with normal and elevated ICP. No significant changes in PaCO2 and f were found in BS pts. Satisfactory analgesia was obtained in 50% of pts of Group 1, and in 88% of pts of Groups 2 and 3. We conclude that tramadol in doses of 0.75 mg/kg and 1.0 mg/kg i.v. does not affect ICP and CPP in adult postcraniotomy patients and seems to be a safe and effective analgesic at a dose of 1.0 mg/kg for postcraniotomy pain control.