Investigating Effective Application Times for Topical Anesthetics in Non-Coring Needle Insertion Over Totally Implantable Venous Access Devices

Abstract

Purpose: This study aims to ascertain the median effective time (ET50) and the 95% effective time (ET95) of EMLA cream and tetracaine hydrochloride gel for analgesia during non-coring needle insertion into totally implantable venous access devices (TIVADs). Patients and Methods: Participants were randomly assigned to either Group E, receiving 2g of EMLA cream, or Group T, receiving 1g of tetracaine hydrochloride gel. Prior to needle insertion, the topical anesthetic was uniformly applied to a 1 cm radius around the puncture site. The initial target application time was set at 60 minutes for Group E and 30 minutes for Group T. For each subsequent participant, the target time was adjusted using a 1:1.1-time gradient, based on the Numeric Rating Scale (NRS) score of the preceding participant. Baseline characteristics, NRS scores, and adverse reactions were documented by a researcher who was not involved in the needle insertion process. The probit analysis method was employed to determine the ET50 and ET95 values. Results: The ET50 and ET95 of patients to achieve painless non-coring needle insertion with EMLA cream were 55.882 minutes (95% Confidence Interval [CI]: 51.369–59.935 minutes) and 63.587 minutes (95% CI: 59.684–92.592 minutes), respectively. In comparison, the ET50 and ET95 for tetracaine hydrochloride gel were 39.092 minutes (95% CI: 36.646–41.678 minutes) and 43.388 minutes (95% CI: 41.111–56.859 minutes), respectively. There was no statistically significant difference between the two groups regarding the incidence of mild and serious adverse reactions. Conclusion: Application of EMLA cream for 64 minutes or tetracaine gel for 44 minutes at the site of TIVADs resulted in a safely conducted, painless non-coring needle puncture for 95% of patients.