Introduction

  • IV calcium is used in replacement and/or cardiac stabilization. Overuse can occur a. Patients with hyperkalemia and hypermagnesemia are commonly given calcium, but calcium is not a definitive treatment for hyperkalemia or hypermagnesemia
  • Ionized calcium versus serum calcium a. Serum (total) calcium represents all calcium in the body, both free and protein bound. This is affected by albumin stores in the body and can severely underestimate a patient's true calcium level b. Ionized (free) calcium represents active calcium in the body. Measuring ionized calcium should be considered prior to treating hypocalcemia, especially in non-emergent cases
  • IV calcium is currently on national drug shortage and consideration should be taken prior to ordering

Clinical Detail

Pharmacology

 Calcium ChlorideCalcium Gluconate
MechanismsNormalizes myocyte excitability by shifting threshold potential
Agonist at calcium channels to restore normal cardiac function in blockade
Formulations100 mg/mL (10%) contains 1.36 mEq EC/mL (3x higher than calcium gluconate)100 mg/mL (10%) contain 0.465 mEq EC/mL.
AdministrationIV push in emergent situations over 2-5 minutes.
Central line administration recommended		Slow IV push administration over 2-5 minutes
May be given as continuous infusion for hypocalcemia
Adverse EffectsArrythmias, bradycardia, cardiac arrest, syncope, tingling, necrosis of tissue (chloride > gluconate)
Drug Interactions and warningsExtravasation: Calcium is a vesicant, administration into tissue can cause necrosis
Not to be used when patient is in ventricular fibrillation in cardiac resuscitation
How suppliedSupplied as a 1 g/10 ml carpuject syringe or vialSupplied as a 1g vial (100 mg/mL)
Clinical PearlsOnset of action has been described as "immediate" but can take up to 5 minutes to start to have effects
The duration of action of calcium is 30-60 minutes

Indications for IV Calcium

UseIndicationsAgentsPearl
Acute/symptomatic hypocalcemiaAcute symptoms and/or ionized calcium < 3mg/dL
Moderate: Muscle twitching, spasms, tingling, numbness
Severe: cardiac dysrhythmias, seizures
Ionized calcium < 3mg/dL		Calcium gluconate
Moderate: 1-4g IV (infusion preferred)
Severe: 1-2g IV, over 10 minutes - may repeat every 60 minutes until symptoms resolve

Calcium Chloride
Moderate: 200mg-1g IV (infusion preferred)
Severe: 1g IV, over 10 minutes, may repeat every 60 minutes until symptoms resolve		Chronic asymptomatic hypocalcemia should be treated with oral calcium
HyperkalemiaPotassium > 5.5 mEq/L + EKG changesCalcium gluconate
1.5-3g IVP over 2-5 minutes

Calcium chloride (cardiac arrest)
1g IVP over 2-5 minutes, repeat as necessary		Calcium is used for heart membrane stabilization, NOT for potassium lowering effects. Additional therapy must be used in combination with calcium to lower potassium levels
Magnesium overloadSevere cardiotoxicity/cardiac arrest
Mild - moderate: nausea, diarrhea, urinary retention, lethargy, muscle weakness
Severe: hypotension, cardiac abnormalities		Calcium gluconate
1.5-3g IVP over 2-5 minutes

Calcium chloride (cardiac arrest)
1g IVP over 2-5 minutes, repeat as necessary		Hypermagnesemia can inhibit parathyroid hormone production leading to hypocalcium, as well as acting as a calcium channel blocking agent at high doses
Current ACLS guidelines recommend against routine use of calcium in the treatment cardiac dysrhythmias
Calcium may be used off-label for calcium channel blocker or beta blocker overdoses on a case-by-case basis

Evidence

Review of Evidence

Author, yearDesignIntervention & ComparisonAssessment
Byrnes, 2004Randomized, retrospective chart reviewOver 38% of calcium levels were classified incorrectly with the corrected serum calcium based on albumin levels as the primary tool of measurement compared to ionized calcium levels.Ionized calcium testing provides a high level of specificity compared to corrected calcium levels. As a result, it should be the primary lab used to assess calcium status in patients requiring management for calcium imbalance.
Peacock, 2018Multicenter, Prospective Observational StudyPatients aged 18 and older diagnosed with hyperkalemia were treated with multiple strategies. The most commonly used therapy employed was insulin/dextrose. IV calcium was used 55% of the time and only 4 of 203 cases employed it as a monotherapy option.Observing major treatments and clinical decision making in multiple U.S. based trauma centers concerning acute hyperkalemia therapy options. Most centers employed at least 3 to 4 combination therapies to treat hyperkalemia. Calcium was almost never used as monotherapy due to its mechanism of action (not potassium lowering)

Conclusions

  • Calcium does not directly lower potassium or magnesium. Additional therapies are needed to affect potassium levels in combination with calcium administration
  • Routine use of calcium in cardiac dysrhythmias is not recommended
  • Ionized and serum calcium are not equal; considerations need to be taken when considering a patients' true calcium level
  • Oral replacement of calcium should be considered first line if patients are stable and/or chronic issue
  • Calcium chloride has a higher risk of extravasation and use should be restricted to cardiac arrest unless a central line is established

References

  • Peacock WF, Frank Peacock W, Rafique Z, et al. Real World Evidence for Treatment of Hyperkalemia in the Emergency Department (REVEAL-ED): A Multicenter,
  • Prospective, Observational Study. The Journal of Emergency Medicine. 2018;55(6):741-750.
  • Parham WA, Mehdirad AA, Biermann KM, Fredman CS. Hyperkalemia revisited. Tex Heart Inst J. 2006; 33(1):40-47.
  • Link MS, Berkow LC, Kundenchuck PJ, et al. 2015 American Heart Associated guidelines updated for cardiopulmonary resuscitation and emergency
  • cardiovascular care. Part 7: adult advanced cardiovascular life support. Circulation. 2015;132:S444-64.
  • Byrnes MC, Huynh K, Helmer SD, Stevens C, Dort JM, Smith RS. A comparison of corrected serum calcium levels to ionized calcium levels among critically ill
  • surgical patients. Am J Surg. 2005;189(3):310-314.
Tags:calcium calcium chloride calcium gluconate hyperkalemia