Retrospective Monocentric Analysis Of Influencing Factors Of Intrathecal Analgesia For Refractory Cancer Pain

Objective: Refractory cancer pain severely affects the mental state,physical function,social activities and living quality of patients with tumors.Intrathecal drug delivery system(IDDS)implantation can effectively treat refractory cancer pain.However,the conversion of opioids from conventional routes to intrathecal route is a challenging phase,the length of the titration process is often affected by many factors.Although IDDS implantation analgesia is widely used and recommended,few studies have analyzed the initial dose of intrathecal drugs.The main objective of this study was to explore the factors associated with early titration completion after IDDS implantation by analyzing the initial dose of intrathecal drugs during the titration phase of IDDS implantation for refractory cancer pain.Materials and methods: All information of 84 patients with refractory cancer pain who underwent IDDS implantation in the Pain Department of the Fourth Hospital of Hebei Medical University from October 2015 to October 2019 was retrospectively collected.General demographic information of patients,tumors type,age and Eastern Cooperative Oncology Group(ECOG)performance status at the time of IDDS implantation were collected.Daily oral morphine equivalent(OME)dose,location of IDDS catheter tip(LICT),daily intrathecal bupivacaine(ITB)dose and daily intrathecal morphine(ITM)dose,ITB to ITM ratio(ITB: ITM),and OME to ITM at the completion of the intrathecal titration(OME: ITM)were also collected.The patients were divided into two groups based on the completion time of the intrathecal titration.E group included patients completing intrathecal titration within 3 days(including the 3th day after surgery).D group included patients completing intrathecal titration after 3 days(excluding the 3th day after surgery).SPSS20.0 was employed in the data analysis.Results: Of the 84 patients who received IDDS implantation for refractory cancer pain,44(52.4%)achieved titration completion within 3 days(Group E),and 40(47.6%)achieved titrat ion completion after 3 days(D group).The median(Q1-Q3)of OME: ITM in the ETC group was 252(244-261);the median(Q1-Q3)of the OME: ITM in the DTC group was 253(248-256).There was no statistically significant difference between the two groups,P = 0.249(P> 0.05).The OME: ITM median(Q1-Q3)of the overall patient was 252(244-256),which is less than the commonly used clinical equivalent ratio of 300: 1.Comparison at a significant level of ? = 0.05 with multivariate logistic regression model showed that the initial intrathecal ITB: ITM was an independent related factor of intrathecal titration influencing factor,P = 0.048(P <0.05),and the cut-off value of the coordinate point corresponding to the maximum value of the Youden's index was 6.875.Conclusion: In the case of IDDS implantation for refractory cancer pain,the equivalent ratio of commonly oral morphine equivalent to intrathecal morphine 300: 1 is higher than the actual clinical value.In this study,the ratio was around 244: 1 to 256: 1.During the intrathecal analgesic titration stage of IDDS implantation,the higher initial intrathecal bupivacaine to morphine ratio is an independent relevant factor to achieve the completion of early titration.In this study,the threshold of the initial intrathecal bupivacaine to morphine ratio is 6.875.