Yokoyama, K., Ikeda, O., Kawanaka, K., Nakasone, Y., Inoue, S., Tamura, Y., & Yamashita, Y. (2014). Pain control in patients with hepatocellular carcinoma treated by percutaneous radiofrequency ablation: Comparison of the efficacy of one-shot and continuous intravenous fentanyl delivery. Acta Radiologica, 55, 1219–1225. 

To determine if the continuous IV infusion of fentanyl during radiofrequency ablation for hepatocellular carcinoma provided better analgesia than medicating via IV bolus before and after the procedure

Eighty-three patients were divided into two groups. Group 1 was given bolus doses of IV fentanyl pre- and postradiofrequency ablation, and group 2 was given a continuous infusion IV fentanyl. The doses were fairly equivocal. The patients were permitted to have IV diazepam if needed during the procedure. It was noted that not all patients used diazepam, and the median doses of diazepam differed significantly between the two groups (Group 1: 7.8 mg, SD = 5.8 mg; Group 2: 4.3 mg, SD = 5.2 mg).

• N = 86  
• AGE RANGE = 61–80 years
• MALES: 58 patients, FEMALES: 25 patients
• KEY DISEASE CHARACTERISTICS: Hepatocellular carcinoma with no metastases or vascular invasion; single tumor up to 5 cm or up to three tumors each less than 3 cm 
• OTHER KEY SAMPLE CHARACTERISTICS: Fifty-seven had hepatitis C; seven had hepatitis B; four had both hepatitis B and C; 15 had nonviral hepatitis

• SITE: Single site    
• SETTING TYPE: Inpatient    
• LOCATION: Kumamoto, Japan

• PHASE OF CARE: Active antitumor treatment
• APPLICATIONS: Elder care  

Prospective trial

• Visual Analog Scale (VAS)

The data indicated that the median VAS score was 4 (SD = 1.8) in group 1 and 3.4 (SD = 1.9) in group 2. The findings were deemed statistically insignificant (p = 0.63). Thirteen patients experienced major toxicities from either the fentanyl or the diazepam (apnea and respiratory depression with decreased oxygen saturation).

The findings of this study indicated that there was no statistically significant difference in pain control reported between the two groups studied.

• Small sample (< 100)
• Risk of bias (no blinding)
• Risk of bias (no random assignment)
• Unintended interventions or applicable interventions not described that would influence results
• Other limitations/explanation: Patients from both groups were offered valium when needed, and the doses varied significantly. Pain was assessed retrospectively three hours after the procedure. Per the terminology in the article, the first 41 patients were assigned to group 1, and the next 42 patients were assigned to group 2. No information was available regarding home medications, specifically of any short- or long-acting analgesic use, which could have had an effect on patients' VAS scores.

This study did not establish compelling evidence that a continuous infusion of fentanyl during radiofrequency ablation and embolization provided significantly better analgesia than the conventional IV boluses pre- and post procedure. I also feel the limitations of the study are significant enough to state that the study should not be used for PEP.