Anesthesia and Critical Care Reviews and Commentary (ACCRAC) Podcast
Episode 176: Keywords Part 11: Barbiturates and Bier Blocks
In this 176th episode I welcome Dr. Gillian Isaac back to the show to discuss another 2 ABA key words. This time we discuss Barbiturates and Bier Blocks. I also take a moment up front to share some thoughts on the horrible tragedy of George Floyd’s death at the hands of the police and the importance of acknowledging white privilege and fighting for the fact that Black Lives Matter.
Reference: Clinical Anesthesia. Publication Year: 2017. Edition: 8th Ed. Authors/Editor: Barash, Paul G.; Cullen, Bruce F.; Stoelting, Robert K.; Cahalan, Michael K.; et al. Outline by Brian Park, MD
Awakening after a single dose of thiopental is caused by redistribution from the brain primarily to which of the following sites? (A) Fat (B) Heart (C) Liver (D) Lung
It is actually the case that follow up studies were done in the US on volunteer patients through University of Arizona and Medical College of Wisconsin in the later 1990’s.Ebert, T., Frink, E. and Kharasch, E. Absence of Biochemical Evidence for Renal and Hepatic Dysfunction after 8 Hours of 1.25 Minimum Alveolar Concentration Sevoflurane Anesthesia in Volunteers. Anesthesiology. 1998;88(3):601-610.
The key point of the final article concludes that humans are nearly devoid of renal beta lyase, the key enzyme in directing biodegradation of compound A to the toxic renal thiol. Essentially, this research was done in the late 90’s but the original possibility of renal toxicity in humans from just a few years prior has stuck in peoples’ minds (and therefore textbooks).
During our discussion of treatment of eclamptic seizures Dr. Henao said benzos were first line treatment. This is assuming the patient is already getting magnesium. For test questions, the answer for first line treatment should be Mg. In reality, patients will likely get both at the same time.
Serum Mg concentrations can be reported as mmol/L, meq/L or mg/dL. The important ranges to know for testing (though in reality different people may get symptoms at different times) are a therapeutic range of 2-3.5 mmol/L or 4-7 mEq/L or 5-9 mg/dL; A loss of patellar reflexes at >3.5, >7, >9; Respiratory paralysis at >5, >10, >12 and cardiac arrest at >12.5, >25, >30. EKG changes including prolonged PR and widened QRS happen in much the same range as loss of patellar reflexes, maybe a bit before but there is a lot of overlap.
Hofmeyr R, Matjila M, Dyer R. Preeclampsia in 2017: Obstetric and Anaesthesia Management. Best Pract Res Clin Anaesthesiol. 2017 Mar;31(1):125-138.
Dhariwal NK, Lynde GC. Update in the Management of Patients with Preeclampsia. Anesthesiol Clin. 2017 Mar;35(1):95-106.
Aya AG, Mangin R, Vialles N, Ferrer JM, Robert C, Ripart J, de La Coussaye JE. Patients with severe preeclampsia experience less hypotension during spinal anesthesia for elective cesarean delivery than healthy parturients: a prospective cohort comparison. Anesth Analg. 2003 Sep;97(3):867-72.
Roberge S, Nicolaides K, Demers S, Hyett J, Chaillet N, Bujold E. The role of aspirin dose on the prevention of preeclampsia and fetal growth restriction: systematic review and meta-analysis. Am J Obstet Gynecol. 2017 Feb;216(2):110-120.
David Chestnut Cynthia Wong Lawrence Tsen Warwick D Ngan Kee Yaakov BeilinJill Mhyre Brian T. Bateman Naveen Nathan. Chestnut’s Obstetric Anesthesia: Principles and Practice. 5th edition. Chapter 36: Hypertensive Disorders. Pg 825-859
Killers of the Flower Moon (Dr. Henao’s random recommendation): https://www.amazon.com/Killers-Flower-Moon-Osage-Murders/dp/0385534248
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