Despite recent advances in non-invasive investigations, percutaneous liver biopsy (PLB) is still considered as the “gold standard” in the diagnosis, assessment and staging of various diseases. It provides an accurate diagnosis in approximately 90 percent of patients with unexplained liver function test abnormalities [8]. A significant degree of anxiety and high level of pain experienced by the patients [9] often limits the willingness of patients with chronic liver disease to undergo subsequent follow-up biopsies. Use of midazolam as sedative for frightened patients has been evaluated in the past [10,11], but its use in the clinical setting has been variable [2]. Sedation used in PLB may interfere with patients’ cooperation and possibly increases the complication rate. Recent published study shown combination of short-acting tramadol and lorazepam is effective, safe and can be used routinely before PLB [12]. Patient-administered nitrous oxide/oxygen inhalation has been evaluated as safe and excellent analgesia for PLB [13], but this is associated with high cost of the system, concern of personnel exposure to the gas, and the need for nursing supervision.
The attitude toward post-procedure pain and its prophylactic use of analgesics, anxiolytic, or sedative drugs is a matter of uncertainty and controversy. Consequently, there is variation between centers in techniques and guidelines for liver biopsy [2,3]. In our center we routinely give pethidine as pre-medication. A pilot trial from our center has shown that pethedine may reduce anxiety and the need for post-procedural pain relief [4]. The potential side effects of pethidine are considerable and include nausea, vomiting, sedation, dizziness, diaphoresis, urinary retention, and constipation. Overdose can cause muscle flaccidity, respiratory depression, hypotension, obtundedness and coma. The use of meperidine (pethidine) has been suggested as a safe analgesic option before percutaneous liver biopsy [14].
We conducted a randomized, placebo-controlled, double blind study to evaluate the need for pethidine in PBL. The results show that the use of pethidine provided a statistically significant pain relief in the immediate post procedural period in comparison to the placebo group but has not long-term effect.
In more detail, the mean VAS score was 0.6 in the pethidine group in comparison to 1.2 in the placebo group immediately after the procedure. Although there is statistically significant difference in the VAS score between the two groups, the VAS score of 1.2 in the placebo group is not considered as a clinically significant pain score as patients with VAS score of 2–3 are still usually quite functional.
Our results also showed that the use of pethedine had no long-term effect and did not impact on the pain score at one hour and 24 hours. With use of local anesthetic and good liver biopsy technique patients tolerated the PLB procedure with minimal pain.
More importantly, the result showed that overall 94% of patients were willing to undergo a repeat procedure if required regardless of whether they have received pethidine or not.
Administration of pethidine did not affect the rate of complications; there were no significant complications observed during the study period. These were consistent with our previous pilot study [11]. The use of pre-procedural ultrasound to identify the ideal location for all PLB, the usage of less traumatic Menghini technique and the supervision by a consultant may have contributed to the low complication rate [15]. There were four patients in the placebo group and five patients in the pethidine group who experienced vasovagal reaction with hypotension; all patients recovered spontaneously and were discharged within the same day of the procedure. The rate of vasovagal events was 10% in the pethidine group and 8% in the placebo group, this was higher than our previous reported rate of 1.3% [4].