E97 - Bayes and Calcium Before Diltiazem in Atrial Fibrillation

You use ketamine. I use ketamine. We all use ketamine. But… how safe it is, really? A new study out of Toronto suggests 30% of patients who receive ketamine have adverse events, a rate higher than seen in the ED. What are we to make of this? I bring Dr Remle Crowe on to discuss…Citations:1.     Kwong JL, Verbeek PR, Leong YC, Turner L, Huiskamp M, Drennan IR, Francom S, Ropp S, Cheskes S: Paramedic use of ketamine for severe agitation and violence. Can J Emerg Med. doi: 10.1007/s43678-025-00963-w (Epub ahead of print).2.     Fernandez AR, Bourn SS, Crowe RP, Bronsky ES, Scheppke KA, Antevy P, Myers JB: Out-of-Hospital Ketamine: Indications for Use, Patient Outcomes, and Associated Mortality. Annals of Emergency Medicine. 2021;78(1):123–31.3.     Brown LH, Crowe RP, Pepe PE, Miller ML, Watanabe BL, Kordik SS, Wampler DA, Page DI, Fernandez AR, Bourn SS, et al.: Adverse events following emergent prehospital sedation of patients with behavioral emergencies: A retrospective cohort study. The Lancet Regional Health - Americas. 2022;May;9:100183.

We've covered pre-oxygenation strategies and intubation alot on this podcast, mayber more than anyting else. We covered the definition of FPS in E74, the DEVICE trial on DL vs VL in E75, and the PREOXI trial of NIV vs Mask Pre-oxygenation in E86. Now we have another Preoxygenation paper, this one that reports no difference between preoxygenation with BVM and face mask. WTAF? Better listen, because it turns out words matter, definitions are... definitional, and we absolutely MUST read more than just the abstract.  Citations:1.     Gottlieb M, Alexander R, Love AK: Comparison of Preoxygenation Strategies for Intubation of Critically Ill Patients. Annals of Emergency Medicine. doi: 10.1016/j.annemergmed.2025.06.621 (Epub ahead of print).2.     Chou CD, Palakshappa JA, Haynie H, Garcia K, Long D, Gibbs KW, White HD, Ghamande S, Dagan A, Stempek S, et al.: Association of Two Preoxygenation Approaches With Hypoxemia During Tracheal Intubation: A Secondary Analysis. Annals of Emergency Medicine. doi: 10.1016/j.annemergmed.2025.06.003 (Epub ahead of print).3.     Pitre T, Liu W, Zeraatkar D, Casey JD, Dionne JC, Gibbs KW, Ginde AA, Needham-Nethercott N, Rice TW, Semler MW, et al.: Preoxygenation strategies for intubation of patients who are critically ill: a systematic review and network meta-analysis of randomised trials. The Lancet Respiratory Medicine. 2025;July;13(7):585–96.4.     Gibbs KW, Semler MW, Driver BE, Seitz KP, Stempek SB, Taylor C, Resnick-Ault D, White HD, Gandotra S, Doerschug KC, et al.: Noninvasive Ventilation for Preoxygenation during Emergency Intubation. N Engl J Med. doi: 10.1056/NEJMoa2313680 (Epub ahead of print).5.     Prekker ME, Driver BE, Trent SA, Resnick-Ault D, Seitz KP, Russell DW, Gaillard JP, Latimer AJ, Ghamande SA, Gibbs KW, et al.: Video versus Direct Laryngoscopy for Tracheal Intubation of Critically Ill Adults. N Engl J Med. 2023;June 16;389(5):418–29.6.     Trent SA, Kaji AH, Carlson JN, McCormick T, Haukoos JS, Brown CA, National EARI: Video Laryngoscopy is Associated With First-Pass Success in Emergency Department Intubations for Trauma Patients: A Propensity Score Matched Analysis of the National Emergency Airway Registry. Ann Emerg Med. doi: 10.1016/j.annemergmed.2021.07.115 (Epub ahead of print).

The 2017 NEJM study, ALPS, compared amiodarone, lidocaine, and placebo for refractory shockable rhythms in adults with out of hospital cardiac arrest. They found no significant difference in survival to hospital discharge or functional survival between any of the arms. If that study has left you confused, you’re not alone. And you’re in luck. Tanner Smida joins us again to discuss his latest paper using something called target trial emulation to assess the difference in ROSC and survival to discharge between amiodarone and lidocaine. This is a great discussion of his paper, the methodology, and how we can put his results into the context of ALPS.Citations:1.Smida T, Crowe R, Price BS, Scheidler J, Martin PS, Shukis M, Bardes J: A retrospective ‘target trial emulation’ comparing amiodarone and lidocaine for adult out-of-hospital cardiac arrest resuscitation. Resuscitation. 2025;March;208:110515.2. Kudenchuk PJ, Brown SP, Daya M, Rea T, Nichol G, Morrison LJ, Leroux B, Vaillancourt C, Wittwer L, Callaway CW, et al.: Amiodarone, Lidocaine, or Placebo in Out-of-Hospital Cardiac Arrest. N Engl J Med. 2016;May 5;374(18):1711–22.3.Hernán MA, Robins JM: Using Big Data to Emulate a Target Trial When a Randomized Trial Is Not Available: Table 1. Am J Epidemiol. 2016;April 15;183(8):758–64.

We just got a new paper that compares initial treatment with adenosine compared with diltiazem for the treatment of adults with SVT in the ED. Wouldn’t it be great if it turned out that diltiazem was just as effective, if not more effective, as adenosine without the crappy feeling? Yeah, that’d be great, but what do we do with statistically insignificant results. Is there, perhaps, a way to save this “insignificant” paper? Fear not, Bayes is here! Yes, that’s right, Dr. Jarvis is grabbing this new paper and diving straight back into that deep dark rabbit hole of Bayesian analysis. Citation:1.     Lee CA, Morrissey B, Chao K, Healy J, Ku K, Khan M, Kinteh E, Shedd A, Garrett J, Chou EH: Adenosine Versus Fixed-Dose Intravenous Bolus Diltiazem on Reversing Supraventricular Tachycardia in The Emergency Department: A Multi-Center Cohort Study. The Journal of Emergency Medicine. 2025;August 1;75:55–64.

The next time you go to intubate a patient, should you give the sedation before the paralytic or the paralytic before the sedative? Does it matter? And what the hell does Bayes have to do with any of this? Dr Jarvis reviews a paper that uses Bayesian statistics to calculate the association between drug sequence and first attempt failure. Then he returns to Nerd Valley to talk about how to interpret 95% confidence intervals derived from frequentists statistics compared to 95% credible intervals that come from Bayesian statistics. Citations:1.     Catoire P, Driver B, Prekker ME, Freund Y: Effect of administration sequence of induction agents on first‐attempt failure during emergency intubation: A Bayesian analysis of a prospective cohort. Academic Emergency Medicine. 2025;February;32(2):123–9. 2.     Casey JD, Janz DR, Russell DW, Vonderhaar DJ, Joffe AM, Dischert KM, Brown RM, Zouk AN, Gulati S, Heideman BE, et al.: Bag-Mask Ventilation during Tracheal Intubation of Critically Ill Adults. N Engl J Med. 2019;February 28;380(9):811–21.3.     Greer A, Hewitt M, Khazaneh PT, Ergan B, Burry L, Semler MW, Rochwerg B, Sharif S: Ketamine Versus Etomidate for Rapid Sequence Intubation: A Systematic Review and Meta-Analysis of Randomized Trials. Critical Care Medicine. 2025;February;53(2):e374–83.

We covered a paper in episode 81 that suggested treating atrial fibrillation with rapid ventricular response in the field could lower mortality. But it also drops BP a bit. Could pretreating these patients with calcium lower the risk of hypotension? Dr Jarvis puts on his nerd hat and uses Bayesian analysis to assess a new randomized, placebo-controlled study that looked at just this thing. Why is he going off on this Bayes thing? Because he’s been reading a couple of book on it and wanted to take it for a spin.  Tables:  Charts: Bayesian Distributions: Citation: 1.     Az A, Sogut O, Dogan Y, Akdemir T, Ergenc H, Umit TB, Celik AF, Armagan BN, Bilici E, Cakmak S: Reducing diltiazem-related hypotension in atrial fibrillation: Role of pretreatment intravenous calcium. The American Journal of Emergency Medicine. 2025;February;88:23–8.2.     Fornage LB, O’Neil C, Dowker SR, Wanta ER, Lewis RS, Brown LH: Prehospital Intervention Improves Outcomes for Patients Presenting in Atrial Fibrillation with Rapid Ventricular Response. Prehospital Emergency Care. doi: 10.1080/10903127.2023.2283885 (Epub ahead of print).3.     Kolkebeck T, Abbrescia K, Pfaff J, Glynn T, Ward JA: Calcium chloride before i.v. diltiazem in the management of atrial fibrillation. The Journal of Emergency Medicine. 2004;May 1;26(4):395–400.4.     Chivers T: Everything Is Predictable: How Bayes’ Remarkable Theorem Explains the World. Weidenfeld & Nicolson, 2024.5.     McGrayne SB: The Theory That Would Not Die. how Bayes’ Rule Cracked The Enigma Code, Hunted Down Russian Submarines & Emerged Triumphant From Two Centuries of Controversy. New Haven, CT, Yale University Press, 2011.

Wrapping up a series of 5 episodes, Dr Jarvis finishes his discussion of mechanical CPR devices (MCDs) talking about papers from Utah, Vienna, Anchorage, and Cincinnati and then gives his take on how to interpret the literature and put it into practice.Papers discussed:1)    Youngquist ST, Ockerse P, Hartsell S, Stratford C, Taillac P: Mechanical chest compression devices are associated with poor neurological survival in a statewide registry: A propensity score analysis. Resuscitation. 2016;September;106:102–7.2)    Zeiner S, Sulzgruber P, Datler P, Keferböck M, Poppe M, Lobmeyr E, Van Tulder R, Zajicek A, Buchinger A, Polz K, et al.: Mechanical chest compression does not seem to improve outcome after out-of hospital cardiac arrest. A single center observational trial. Resuscitation. 2015;November;96:220–5.3)    Levy M, Yost D, Walker RG, Scheunemann E, Mendive SR: A quality improvement initiative to optimize use of a mechanical chest compression device within a high-performance CPR approach to out-of-hospital cardiac arrest resuscitation. Resuscitation. 2015;July;92:32–7.4)    Morgan S, Gray JJ, Sams W, Uhl K, Gundrum M, McMullan J: LUCAS Device Use Associated with Prolonged Pauses during Application and Long Chest Compression Intervals. Prehospital Emergency Care. 2023;March 9;28(1):114–7.5)    Grunau B, Reynolds J, Scheuermeyer F, Stenstom R, Stub D, Pennington S, Cheskes S, Ramanathan K, Christenson J: Relationship between Time-to-ROSC and Survival in Out-of-hospital Cardiac Arrest ECPR Candidates: When is the Best Time to Consider Transport to Hospital? Prehospital Emergency Care. 2016;September 2;20(5):615–22. 

Last episode we described the literature showing no survival benefit to patients with the AutoPulse device. Fear not, I wasn’t ignoring the LUCAS, I just felt it deserved it’s own episode. We’ll cover the LINC and PARAMEDIC randomized controlled trials and the secondary analysis of LINC in shockable rhythms. I switched to a new production process using a new mic (Rode NT1) and started using ecamm to record. Yes, I know there is a bit of AV dysynchrony.. I’m working on it. I still have a lot to learn about ecamm but am optimistic about it. Citations on LUCAS device:1. Rubertsson S, Lindgren E, Smekal D, Östlund O, Silfverstolpe J, Lichtveld RA, Boomars R, Ahlstedt B, Skoog G, Kastberg R, et al.: Mechanical Chest Compressions and Simultaneous Defibrillation vs Conventional Cardiopulmonary Resuscitation in Out-of-Hospital Cardiac Arrest: The LINC Randomized Trial. JAMA. 2014;January 1;311(1):53–61.2. Perkins GD, Lall R, Quinn T, Deakin CD, Cooke MW, Horton J, Lamb SE, Slowther A-M, Woollard M, Carson A, et al.: Mechanical versus manual chest compression for out-of-hospital cardiac arrest (PARAMEDIC): a pragmatic, cluster randomised controlled trial. The Lancet. 2015;385(9972):947–55.3. Hardig BM, Lindgren E, Östlund O, Herlitz J, Karlsten R, Rubertsson S: Outcome among VF/VT patients in the LINC (LUCAS IN cardiac arrest) trial—A randomised, controlled trial. Resuscitation. 2017;June;115:155–62. Citations on Jeff’s Tamiflu Rant1. Jefferson T, Jones M, Doshi P, Spencer EA, Onakpoya I, Heneghan CJ: Oseltamivir for influenza in adults and children: systematic review of clinical study reports and summary of regulatory comments. BMJ. 2014;348:g2545.2. Jefferson T, Jones MA, Doshi P, Del Mar CB, Hama R, Thompson MJ, Onakpoya I, Heneghan CJ: Risk of bias in industry-funded oseltamivir trials: comparison of core reports versus full clinical study reports. BMJ Open. 2014;4(9):e005253.3. Jefferson T: The Tamiflu Story: Why We Need Access To All Data From Clinical Trials. Open Knowledge Foundation Blog.

Our story so far.. episode 92 looked at a study showing lower survival from in-hospital cardiac arrest in patients treated with mechanical compression devices. Episode 93 discussed an implementation study of implementing LUCAS devices in a system with high quality pit crew CPR also showing lower survival, despite spending lots of time in training on how to optimally apply the LUCAS to avoid prolonged compression interruptions and movement. Now we’re diving into the literature around AutoPulse, the load-distributing band device. We’ll cover two randomized controlled trials and one well-done observational study comparing AutoPulse to manual CPR. Don’t worry, LUCAS studies will be in the next episode.Citations1. Hallstrom A, Rea TD, Sayre MR, Christenson J, Anton AR, Mosesso VN, Van Ottingham L, Olsufka M, Pennington S, White LJ, et al.: Manual Chest Compression vs Use of an Automated Chest Compression Device During Resuscitation Following Out-of-Hospital Cardiac Arrest: A Randomized Trial. JAMA. 2006;June 14;295(22).2. Ong MEH, Ornato JP, Edwards DP, Dhindsa HS, Best AM, Ines CS, Hickey S, Clark B, Williams DC, Powell RG, et al.: Use of an Automated, Load-Distributing Band Chest Compression Device for Out-of-Hospital Cardiac Arrest Resuscitation. JAMA. 2006;June 14;295(22).3. Wik L, Olsen J-A, Persse D, Sterz F, Lozano M, Brouwer MA, Westfall M, Souders CM, Malzer R, Van Grunsven PM, et al.: Manual vs. integrated automatic load-distributing band CPR with equal survival after out of hospital cardiac arrest. The randomized CIRC trial. Resuscitation. 2014;June;85(6):741–8.

Ever wonder what would happen to cardiac arrest survival after a system implements LUCAS devices and trains really hard to deploy them appropriately? Wonder no more. Dr Jarvis reviews a paper from the Austin/Travis County EMS System that will shed some light on the question. This is the second episode in a series on mechanical compression devices.  Citations:1.     Gonzales L, Oyler BK, Hayes JL, Escott ME, Cabanas JG, Hinchey PR, Brown LH: Out-of-hospital cardiac arrest outcomes with “pit crew” resuscitation and scripted initiation of mechanical CPR. The American Journal of Emergency Medicine. 2019;May;37(5):913–20.2.     Crowley C, Salciccioli J, Wang W, Tamura T, Kim EY, Moskowitz A: The association between mechanical CPR and outcomes from in-hospital cardiac arrest: An observational cohort study. Resuscitation. 2024;May 1;198.