The Inclusion of Bupivacaine inside the Spinal tray should be forbidden
- The Inclusion of Bupivacaine inside the Spinal tray should be forbiddenIt is a common practice for many years in the USA to include the Bupivacaine ampoule in the Spinal tray and then sterilize the spinal tray with the Bupivacaine inside it.There are several cases known to me where the spinal anesthesia failed due to "unknown" reason.The Sterilization process of a spinal kit necessitates the use of a temperature of 55 degrees Celsius for more than 8 hours : http://www.csen.com/ster.jpgHowever, according to the Bupivacaine manufacturer : "Storage Conditions: Store out of direct sunlight in a cool, well ventilated, dry area." : http://www.pfizer.com/files/products/material_safety_data/PZ00763.pdfHowever, you cannot call "a temperature of 55 degrees Celsius for more than 8 hours " during the sterilization process "a cool, well ventilated, dry area".I am also not aware on any study examining the composition of Bupivacaine immediately after such a sterilization process.For example, "bupivacaine degradation into pipecolylxylidine (PPX), its major metabolite" : http://www.csen.com/bup-met.pdfSo, the question is: After these 8 hours of sterilization inside the spinal tray are you injecting Bupivacaine or Pipecolylxylidine (PPX) into the Spinal canal?Joseph Eldor, MD------------------------------
October 17, 2009
1:00 PM - 2:30 PM
Failed Spinal Anesthesia Due to Chemically Altered Bupivacaine Brian Blasiole, M.D., Ph.D., John Williams, Ph.D., Krishnan Damodaran, Ph.D., Sukhdip Singh, M.D., Manuel C. Vallejo, M.D.
Anesthesiology, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania
Introduction: A failed neuraxial block is a neuraxial procedure resulting in inadequate anesthesia/analgesia or no block after adequate dosing. Using mass spectroscopy (MS) and nuclear magnetic resonance (NMR) imaging, we identified a lot-specific, chemically altered bupivacaine as the cause of 8 failed spinal anesthetics at our institution.
Clinical Course: Our anesthesia service experienced 8 cases of failed spinal anesthetics in a 1 week period. The failures in 6 elective Cesarean sections and 2 lower extremity orthopedic procedures resulted in inadequate sensory block, prolonged onset of block, insufficient duration of block, or no block. These failures occurred in the hands of 5 staff anesthesia providers and were limited to 3 suspect lot numbers of unexpired BD Spinal Anesthesia Trays. In all cases, the same standardized technique for administering spinal anesthesia was used including free flow of cerebral spinal fluid before, during, and after placement of hyperbaric bupivacaine (0.75% with dextrose 8.25%) using a 25-gauge Whitacre spinal needle and pin-prick assessment of dermatomal levels. Considering a
>90% neuraxial placement rate at our tertiary care medical centerspecializing in womancare, the clustering of these failures suggested a defect in the spinal bupivacaine administered. A negative batch analysis and unremarkable testing of retained samples by the drug manufacturer led us to suspect drug stability issues in transit/storage. We tracked the shipment of the 3 suspect lots of spinal kits and found they were stored for >9 hours in a non-temperature controlled delivery truck at temperatures below freezing. Using MS, we analyzed samples of spinal bupivacaine and found the suspect drug had a mass/charge (m/z) ratio of 276 compared to the control sample mass to charge of 289 (molecular mass of bupivacaine is 289; Fig. 1). Further analysis of the suspect bupivacaine using NMR revealed a spectrum different from that of the control sample, confirming our suspicion of a chemical alteration of the drug used in the failed spinal anesthetics.
Discussion: In this report, we describe eight cases of failed spinals due to chemically altered spinal bupivacaine as evidenced by MS and NMR analysis. We believe that the structural change in the bupivacaine was caused by exposure to freezing temperatures during transit. The bupivacaine product insert recommends storage at 20-25°C and protection from freezing. Interestingly, one study found no change in the concentration of bupivacaine with 5-days exposure to cold (-18°C) or heat (50°C) using a GC/MS assay.1 Other documented reports of failed spinal anesthesia associated with specific batch/lot numbers of bupivacaine do not comment on the cause of type of the chemical defect.2-3 We are in the process of characterizing the chemical alteration in the suspect bupivacaine using additional NMR analysis and hope to elucidate the responsible mechanism.[figure1]References:
1. Anesthesiology 2007; 106 (Supp 1): 11
2. Int J Ostet Anesth 2003; 13:310-1
3. Int J Ostet Anesth 2004; 13:131-4.
From Proceedings of the 2009 Annual Meeting of the American Society Anesthesiologists.