Analgesic Efficacy of Epidural Patient-Controlled Analgesia on Cancer Pain: A Retrospective Observational Study.

ABSTRACT

BACKGROUND: In patients with severe cancer pain, systemic analgesics are often refractory or have limited application due to the side effects of opioids. In these cases, epidural analgesia may be effective. However, data on the effects of epidural patient-controlled analgesia (PCA) on cancer pain are limited. OBJECTIVES: To evaluate the analgesic efficacy of epidural PCA in patients with cancer pain through a retrospective chart review. STUDY DESIGN: Retrospective analysis. SETTING: A single academic center in Daegu, South Korea. METHODS: The analgesic efficacy of epidural PCA on cancer pain was analyzed in patients who underwent epidural PCA using a disposable balloon pump with a flow regulator between 2012 and 2021. The pump was filled with a 600-mL mixture of 6 ampoules of 0.2% ropivacaine, 1 mg fentanyl, and normal saline. For the first use of epidural PCA, the basal rate, bolus dose, and lockout time were set as 4 mL/h, 2 mL, and 15 min, respectively. The basal rate was increased and decreased depending on the degree of pain relief effect and occurrence of side effects, respectively. To increase the usage time of epidural PCA and reduce the patient's cost burden, the fentanyl dose was increased by 1 mg when the disposable balloon pump was replaced with a new one after exhaustion of the drug if no side effects from the previous dose were observed. Analgesic efficacy was confirmed by comparing the number of types and the total amount of opioids used in patients before and after epidural PCA application in terms of the equivalent dose of oral morphine. RESULTS: Epidural catheterization was performed 105 times, and PCA was refilled 257 times in 88 patients. On average, epidural catheterization was performed 1.2 ± 0.4 (1-3) times, and epidural PCA was refilled 3.2 ± 2.3 (1-11) times per patient. The mean duration of PCA use was 15.6 ± 13.4 (1-82) days. The mean number of opioid types used the day before the procedure and the mean smallest number of opioids used per day up to 5 days after the procedure were 3.4 ± 1.2 and 2.4 ± 1.4, respectively (P < 0.05). The total amount of opioids used the day before the procedure and the smallest total amount of opioids used per day up to 5 days after the procedure were converted into oral morphine equivalent doses, respectively, and the mean doses were 449.5 ± 555.9 and 331.9 ± 462.8 mg, respectively (P < 0.05). LIMITATIONS: The study results are the author's observations from a single center. Epidural PCA was performed only on hospitalized patients. Individual differences were not considered in the composition of drugs for PCA. Transmucosal immediate-release fentanyl was not accurately converted to oral morphine; thus, it was excluded from the analysis of the total amount used, and the effect of adjuvant analgesics could not be considered. CONCLUSION: Epidural PCA using subcutaneous tunneling is a useful cancer pain control method. Furthermore, it can be safely used for a longer duration owing to its low infection risk.