Feedback from an error in the preparation of intrathecal analgesia

Background
Intrathecal analgesia (ITA) typically involves the administration of a triple-drug therapy (morphine, ziconotide, amide anesthetic) directly in the cerebrospinal fluid in patients with refractory chronic cancer-related pain. The preparation process must follow a validated procedure and be under sterile conditions to limit iatrogenic and infectious risks. An incident occurred during preparation, wherein the morphine and ziconotide syringes were mistakenly interchanged. The error was caught during the double visual pharmaceutical control (DVPC).

Objective
This study aims to assess the changes in the preparation practices of ITA syringes in our production unit following the preparation error mentioned above.

Materials and methods
Continuous video recording of the isolators enabled in-depth retrospective analysis of the preparation process. A Feedback Committee (CREX) was set up. The ALARM analysis was carried out by two pharmacists, a quality manager, a pain management nurse and doctor.

Results
The video analysis enabled a chronological description of events, and the identification of the causes and contributing factors to the error. The prescription required 25 mL bupivacaine, 3.6 mL morphine, and 11 mL ziconotide diluted at a 1/10 ratio. However, during dilution, 3 mL of pure ziconotide was inadvertently replaced with morphine, potentially resulting in an administered dose of morphine that was -2.9 times the intended amount and a ziconotide dose that was 2.7 times the intended amount. Among the factors identified, the use of a secondary isolator not dedicated to ITA had been required, with a different organization of storage. The sterilization airlock was out of order, leading to transfers via a sterile transfer container from another isolator. The incorrect replenishment of supplies resulted in the injections being made out of order. Furthermore, four preparations were to be made that day with varying morphine and ziconotide dilutions (1/5th or 1/10th).

Discussion – Conclusion
In our process, the challenge of ITA preparation arises from the absence of controls outside the DVPC. To address this issue, we have implemented additional corrective measures. Dilutions, identified as an error factor, have been abolished per the prescribers’ agreement. The findings of the CREX and the videos have been presented to the pharmacy technicians as part of their ongoing training. The procedure has also been adjusted: drugs are taken one after the other in a specific sequence. The volume of the first drug is withdrawn, checked by the pharmacist, and now directly injected into the final syringe. Then the same procedure is then repeated for the second and third drugs, thus eliminating the need for syringes to be left on standby. Given the potential clinical implications, it is essential to standardize the DVPC methodology and make it as rigorous as possible for ITA. The pharmaceutical validation through video will be tested.