Topics in this EM Quick Hits podcast

David Juurlink on acetaminophen and warfarin drug interaction (00:32)

Hans Rosenberg on management of dental infections (08:03)

Emily Austin on dialysis in massive acetaminophen overdose (14:46)

Andrew Petrosoniak MTP decisions and the RABT score in trauma (20:05)

Joel Yaphe on statins for STEMI from Whistler’s Update in EM Conference (26:49)

George Kovacs on how to maximize success of a cricothyrotomy from EM Cases Course 2019 (31:25)

Podcast production, editing and sound design by Anton Helman

Podcast content, written summary & blog post by Emily Austin, Anton Helman, Andrew Petrosoniak and Hans Rosenberg, edited by Anton Helman

Cite this podcast as: Helman, A. Juurlink, D. Rosenberg, H. Austin, E. Petrosoniak, A. Yaphe J. Kovacs, G. EM Quick Hits 4 – Acetaminophen and Warfarin Interaction, Dental Infections, MTP Prediction in Trauma, Massive Acetaminophen Overdose, Statins in STEMI, Cricothyrotomy Tips. Emergency Medicine Cases. May, 2019. [date].

Acetaminophen and Warfarin Drug Interaction

  • Some people who take ≥ 2-3g of acetaminophen daily will produce enough NAPQI, a toxic byproduct that will interfere with the gamacarboxylase enzyme that requires Vitamin K as a co-factor, causing the INR to reach dangerous levels.
  • A small double blind RCT from 2006 patients on stable oral anticoagulant therapy with warfarin for at least 1 month were randomized to receive placebo or acetaminophen 1g four times daily for 14 days. Mean INR rose rapidly after the start of acetaminophen and the INR values reached a mean maximum of 3.45 with acetaminophen versus 2.67 with placebo. While this may be considered a small increase, some patients, for unexplained reasons, will have an increase far greater.
  • Think twice about prescribing acetaminophen or any product containing acetaminophen to patients taking warfarin; and for any patient who presents with bleeding while taking warfarin, ask about acetaminophen use.

  1. Mahé I, Bertrand N, Drouet L, et al. Interaction between paracetamol and warfarin in patients: a double-blind, placebo-controlled, randomized study. Haematologica.2006;91(12):1621–7.
  2. Caldeira D, Costa J, Barra M, Pinto FJ, Ferreira JJ. How safe is acetaminophen use in patients treated with vitamin K antagonists? A systematic review and meta-analysis. Thromb Res. 2015;135(1):58-61.
  3. Lopes RD, Horowitz JD, Garcia DA, Crowther MA, Hylek EM. Warfarin and acetaminophen interaction: a summary of the evidence and biologic plausibility. Blood.2011;118(24):6269–73.

Dental Infections

  • Differentiate pulpitis versus a periapical abscesses by considering the duration of the pain and secondary signs such as tooth elevation, swelling, adjacent cellulitis, lymphadenopathy and fever.
  • The definitive treatment of both pulpitis and periapical abscesses require a dentist. Your role in the ED is to diagnose, treat the pain (avoiding opioids whenever possible) and consider antibiotics based on patient factors, both physiological and social.
  • Most guidelines suggest that there is no role for antibiotics for uncomplicated periapical abscesses.
  • In a review of two RCT in Annals of EM, patients presenting with dental pain without overt signs of infection were not found to benefit from penicillin. In one of the RCTs they found the same scores for sum pain intensity, total ibuprofen taken, and percentage of patients with vital teeth. In the other study, they found an infection rate of 6- 7 % in both groups and no difference in visual analog pain scores.
  • A watchful waiting approach with a prescription for penicillin for 7-10 days (to be taken if symptoms or signs of complicated periapical abscess develop), may be appropriate for patients who are unable to see a dentist for social or financial reasons.

  1. Gottlieb M, Khishfe B. Are Antibiotics Necessary for Dental Pain Without Overt Infection?. Ann Emerg Med. 2017;69(1):128-130.
  2. Robertson DP, Keys W, Rautemaa-richardson R, Burns R, Smith AJ. Management of severe acute dental infections. BMJ. 2015;350:h1300.

Massive Acetaminophen Overdose: Dialysis

  • Acetaminophen poisoning is usually effectively treated with the antidote N-acetylcysteine which helps in the elimination of NAPQI, the toxic metabolite.
  • In the setting of a massive acetaminophen overdose (for example, > 500 mg/kg) patients can present with altered mental status and an anion gap metabolic lactic acidosis due to mitochondrial dysfunction. Often, there is no sign of hepatic injury in these patients.
  • Patients with a massive acetaminophen overdose may benefit from hemodialysis. The EXTRIP recommendations give specifics about when hemodialysis should be considered, and are available here:

  1. EXTRIP- Acetaminophen:
  2. Roth B, Woo O, Blanc P: Early metabolic acidosis and coma after acetaminophen ingestion. Ann Emerg Med April 1999; 33:452-456.
  3. L. A. Sivilotti, D. N. Juurlink, J. S. Garland, I. Lenga, R. Poley, L. N. Hanly & M. Thompson. Antidote removal during haemodialysis for massive acetaminophen overdose. Clin Tox 2013; 51:9: 855-863.

Massive Transfusion Protocol: RABT Score to Predict the Need for MTP

  • Several scores have been studied to help predict the need for massive transfusion for bleeding trauma patients
    1. Shock index (HR/sBP) >1.0: Sensitivity 67%; Specificity 81%
    2. ABC Score >2: Sensitivity 75%; Specificity 86% (original study), subsequent study less sensitive (<50%)
  • The Revised Assessment of Bleeding and Transfusion (RABT) Score:
    1. Shock index > 1.0
    2. Pelvic Fracture
    3. Positive FAST
    4. Penetrating Injury
  • 2018 study showed RABT score ≥ 2 performed better than ABC score in predicting need for MTP
    1. Sensitivity 84%; Specificity 77%
    2. Limitations: not prospectively validated
  • Despite the limitations of this study, consider incorporating the RABT score elements into your decision making for activating MTP among bleeding trauma patients.

  1. Joseph B et al. Massive Transfusion: The Revised Assessment of Bleeding and Transfusion (RABT) Score. World J Surg 2018 Nov 42(11): 3560-3567
  2. Schroll R et al. Accuracy of shock index versus ABC score to predict need for massive transfusion in trauma patients. Injury 2018 Jan;49(1):15-19.
  3. Nunez et al. Early prediction of massive transfusion in trauma: simple as ABC(assessment of blood consumption)? J Trauma 2009 Feb 66(2): 346-52.

Statins in STEMI: SECURE-PCI Trial

  • A multicenter RCT of 4,191 patients in Brazil compared the safety and efficacy of two loading doses of atorvastatin (80 mg each) vs placebo given immediately and 24 hours after PCI in patients presenting to the ED with ACS for whom an early PCI was planned. All patients received 40 mg/d of atorvastatin after PCI for 30 days
  • The primary outcome, major adverse cardiac events (MACE), for statin vs. placebo, was 6.2% vs. 7.1%, p = 0.27 – no significant difference
  • However, in the subgroup of patients with STEMI who had PCI, MACE at 30 days occurred in 30 of 417 patients in the atorvastatin group and in 58 of 448 patients in the placebo group (HR, 0.54; 95% CI, 0.35-0.84; P = .01), with a 41% reduction in reinfarction going for PCI
  • No cases of rhabdomyolysis or liver failure were reported in the atorvastatin group
  • Consider adding 80mg atorvastatin to ED STEMI order sets

  1. Berwanger O, Santucci EV, de Barros e Silva PG, et al., on behalf of the SECURE-PCI Investigators. Effect of Loading Dose of Atorvastatin Prior to Planned Percutaneous Coronary Intervention on Major Adverse Cardiovascular Events in Acute Coronary Syndrome: The SECURE-PCI Randomized Clinical Trial. JAMA 2018;319:1331-40.

Tips to Maximize Chances of Cricothyrotomy Success

  • The 11 steps of a bougie cricothyrotomy, the preferred technique, like any HALO (High Acuity, Low Opportunity) procedure, requires practicing/overlearning the mechanics through deliberate practice under duress in simulations so that muscle memory is engrained and the procedure can be executed as a single event
  • The decision to do the procedure is often the most difficult and step and can be made easier by discussing the possibility of cricothyrotomy with your team in all airway patients and palpating the neck in advance
  • The inability to ventilate is best anticipated by end-tidal CO2 monitoring; if laryngoscopy and supraglottic attempts have failed and end-tidal CO2 continues to trend downward, a cricothyrotomy should be attempted
  • Ensure that the larynx is adequately stabilized before cutting to avoid self injury and cutting para-tracheal

Practice your cricothyrotomy skills with SimKit’s home delivery of their excellent cric model and simulation videos

None of the authors have any conflicts of interest to declare