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A3033
October 21, 2019
10/21/2019 9:30:00 AM - 10/21/2019 11:30:00 AM
Room WA2 - Area D
The Impact of Nationwide Hyperbaric Bupivacaine Shortage on Spinal Anesthesia in Patients Undergoing Postpartum Bilateral Tubal Ligation
Jeffrey Chen, M.D., Maria Lima, B.A., Nwamaka P. Nnamani, M.D., Emily Melikman, M.D., Tristyn St. Thomas-Ochoa, M.D., Enas Kandil, M.D.
UT Southwestern, Dallas, Texas , United States
Disclosures: J. Chen: None.M. Lima: None.N.P. Nnamani: None.E. Melikman: None.T. St. Thomas-Ochoa: None.E. Kandil: None.
Background: Medication shortages are not a new phenomenon, but unfortunately they can hurt patient care due to inadequate alternatives or increased user error.1 At our institution, a recent shortage of hyperbaric bupivacaine (HB) required us to switch to isobaric bupivacaine (IB) as our alternative spinal anesthetic for postpartum bilateral tubal ligation (BTLs), a method which aligned with SOAP recommendations.2 However, despite the similarities, isobaric bupivacaine appeared to result in more failed spinal blocks. This retrospective observational study seeks to quantify the outcome and elucidate the impact of this bupivacaine shortage on spinal anesthesia.

Methods: Epic EMR chart review of over 300 patients who received postpartum BTLs at Parkland Hospital between June 1st 2017 and August 31st 2018 were screened for a total of 150 patients per group (HB vs. IB). Eligible patients were those over 18 years old who received a neuraxial block (spinal or combined spinal epidural). Data on patient demographics, comorbidities, difficulties during spinal procedure (>1 attempt), anesthesia provider level, volume and dose of bupivacaine, and level of spinal block were collected. Additionally, need for conversation to general anesthesia, intraoperative supplemental anesthetic medications (midazolam, fentanyl, propofol, or ketamine), vasopressor use (phenylephrine or ephedrine) and hemodynamic variables were compared.

Results: Demographic data demonstrated no significant difference between HB and IB groups (Table 1). The dose of bupivacaine (mg) was also similar (p >0.05). The most common level of spinal needle insertion was L3-4 in both groups (75.33% HB, 80.0% IB). The most common spinal block level was T4 (92 patients HB, 88 patients IB). Percentage of low spinal blocks, defined as level lower than or equal to T6, was not significantly different (p >0.05). The number of failed spinal blocks, defined as the percentage of spinal blocks that required conversion to general anesthesia, was significantly higher in the IB group (8.67% vs 2.67% in HB, p <0.025). The IB group also required more supplemental anesthetic such as midazolam (p = 0.0027), fentanyl (p < 0.00001), and propofol (p = 0.0029). Ketamine use was not significantly different. Combined use of phenylephrine and ephedrine was not significantly different between the two groups.

Conclusion: Medication shortages will continue to occur, but the impact is often difficult to quantify. Unfortunately, in this scenario, substitution of hyperbaric bupivacaine with isobaric bupivacaine shows an increase in failed spinal blocks for postpartum BTLs. The resultant unintended intubation or sedation exposes a peripartum patient to additional risks of airway complications or medication side effects. Possible explanations for these findings include differences in the density of block, distribution of the block, and operator unfamiliarity with the isobaric formulation.3



References:

[1] De Oliveira G, Theilken L, McCarthy R. Shortage of perioperative drugs: implications for anesthesia practice and patient safety. Anaesth Analg. 2011;113(6):1429-35.

[2] Society for Obstetric Anesthesia and Perinatology 2018, accessed March 30th 2019, <https://soap.org/2018-bupivacaine-shortage-statement.pdf>

[3] Beecroft, Christina. Spinal anaesthesia. Anaesth Intensive Care. 2015;16(11):563-565$$graphic_{6CAAA22F-D466-4F3A-AC0F-BE06E06BF31F}$$
Figure 1

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