Jun 15, 2014 · Leave a Reply

The hypotensive and bradycardic patient

By Daniel Cabrera, M.D. @cabreraerdr

Notes from Ben Sandefur Grand Rounds "The hypotensive and bradycardic patient"

By Damian Baalmann, M.D.

sandefur1

Broad Differential for Hypotensive + Bradycardic Patient

  1. Toxic
    1. CCB
    2. Beta Blocker
    3. Cardiac Glycodisde (Digoxin)
    4. Alpha-2 Agonist (Clonidine)
    5. Organophosphate
  2. Cardiac
    1. Cardiac Conduction Disease
      1. Infarction
      2. Primary Conduction Disease
      3. Pacemaker Failure
      4. Infectious: Lyme Carditis/ Chaga’s Disease
  3. Electrolyte
    1. Hyperkalemia
  4. Endocrine
    1. Hypoadrenalism
    2. Hypothyroidism
  5. Environmental
    1. Hypothermia
  6. Gastrointestinal
    1. Massive GI Bleed (vaso-vagal response)
  7. Neurogenic
    1. Neurogenic Shock

  • Remember that often the presentation is multifactorial. Additionally, bradycardia + hypotension is often the final common pathway for dying patient, regardless of etiology.

Calcium Channel Blockers

  • Classic Non-Dihyhdropyridine CCB overdose: Hypotensive, Bradycardic, and Hyperglycemic

Beta-Blockers

  • Pharmacology: G-Protein Linked Receptor→Adenylyl cyclase→cAMP→PKA
  • Beta-Blocker Overdose: Hypotensive, Bradycardic, Hypo- or Normoglycemic
    • CNS effects with propranolol (b/c it crosses the BBB)

Therapeutic Options for CCB or Beta-Blocker Toxic Patient

  • Give Calcium!
    • Calcium Gluconate: PIV, dose: 3-6g
    • Calcium Chloride: Central access, dose: 1-2g
  • Glucagon
    • Activates G-protein and bypasses B-blocker
  • Amrinone
    • Increases cAMP in the cell
  • Vasopressors
    • Works on Beta receptor
  • Insulin
    • Overcomes hypoglycemia of CCB
    • Glucose entry in the Myocytes →increase ionotropy
    • Bolus 1U/kg, infusion 1-10U/kg/hr, D10 @100mL/hr, replete K+, avoid vasopressors
  • Intralipid Therapy
    • 1.5 mL/kg of 20% solution of 2-3min; 0.25-0.5 mL/kg/min drip for 30-60 min
    • Data not quite as robust as hyperinsulinemia therapy
  • Also think of Transvenous Pacemaker, Intra-aortic balloon pump, ECMO, Cardioplumonary Bypass

Summary

  • Think broadly with differential of hypotension and bradycardia
  • Animal data strongly supports using insulin for increasing survival in CCB and beta-blocker; vasopressors ↑SVR and may be counterproductive
  • Glucagon, Vasopressors, and Amrinone all display tachyphylaxis because they rely on cAMP pathway which eventually is depleted
  • Consult Poison Control Center Early: 1-800-222-1222
  • High-dose insulin therapy has emerged as an effective therapy for CCB and beta-blocker toxicity
  • Lipid Emulsion Therapy may be helpful in cardiotoxicity or cardiac arrest from lipophilic cardiotoxic medications, but the data is not as compelling

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