Thursday Conference Content

From the EMDaily Archives: Thrombolytics in STEMI by Dr. Katie Nowlan

Fibrinolysis:

  • In the absence of contraindications, should be given to STEMI patients with symptoms <12 hours when it is anticipated that primary PCI cannot be performed within 120 minutes of first medical contact (class I recommendation) 
  • Up to 12-24 hours of symptoms with STEMI when PCI unavailable (class IIa recommendation)

When to choose thrombolytics? 

  • Non-PCI capable hospital and the total time it would take to transfer to a PCI-capable hospital and first medical contact–device time is > 120 min away
  • Ideally administered within the first 30 minutes of presentation

Thrombolytic agents:

  • tPA: 15 mg IV over 1-2 min, followed by 50 mg IV over 30 min, followed by 35 mg IV over 60 min (total 100 mg over 1.5 hours)
  • TNKase: 30-50 mg IV over 5 sec (dosing is weight based) 
  • rPA: 10 Units x 2 given 30 min apart 

Absolute contraindications:

  • Any prior intracranial hemorrhage
  • Ischemic stroke within 3 months (except acute ischemic stroke within 4.5 hrs) 
  • Known structural cerebral vascular lesion (e.g. AVM) or intracranial neoplasm (primary or metastatic) 
  • Active bleeding or bleeding diatheses (excluding menses)
  • Intracranial or intraspinal surgery within 2 months
  • For streptokinase, prior treatment within the previous 6 months
  • Significant closed-head or facial trauma within 3 months
  • Suspected aortic dissection
  • Severe uncontrolled hypertension unresponsive to emergency therapy

Adjunctive Therapies to thrombolytics:

  • Aspirin: 162 to 325 mg loading dose 
  • Clopidogrel: 300 mg for ≤75 years old; 75 mg for >75 years old 
  • Unfractionated heparin bolus or enoxaparin or fondaparinux

Final points:

  • Transfer! Regardless of hemodynamics or reperfusion success, it is reasonable to still get patients to a PCI-capable center.
  • Angiography recommended within the first 24 hours but AVOIDED for the first 2-3 hours after fibrinolytic therapy.
Thursday Conference Content

Lidocaine Anesthetic Systemic Toxicity (LAST)

Dr. Carlos Cevallos, M.D.

Overview:

Local anesthetics are a class of medications that includes esters and amides such as benzocaine/procaine and bupivacaine/lidocaine respectively

Local anesthetics MOA: Primarily through inhibition of voltage-gated sodium channels

Risk Factors for development of LAST:

  • High volume nerve blocks, lack of ultrasound guidance, prolonged high-dose lidocaine infusions, hepatic dysfunction, cardiac disease, renal disease, pregnancy

Clinical Presentation: Primarily affects the CNS and cardiovascular system

CNS: usually presents first

  • Sensory: tinnitus, perioral numbness, perioral numbness, metallic taste, blurred vision
  • Dizziness
  • Delirium
  • Tremors, lethargy
  • Dysarthria
  • Seizures
  • Respiratory depression

Cardiovascular symptoms:

  • Initial: Sympathetic activation (tachycardia, HTN, diaphoresis)
  • Late: Bradycardia, AV block, widened QRS, ventricular arrhythmias, PEA/Asystole

Treatment: 

  • Immediately discontinue the anesthetic
  • Lipid Emulsion therapy:
    • Initial: 1.5ml/kg bolus of Intralipid 20% followed by infusion at 0.25ml/kg/min until 10 minutes after hemodynamic stability is obtained
    • If HD stability not obtained then you may re-dose the 1.5ml/kg bolus twice and increase the infusion to 0.5ml/kg/min