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PICO Question:
In cats and dogs with CPA associated with hyperkalemia (P) does the use of no calcium during CPR (I) compared with calcium administration (C) improve outcome (O)?

Favorable neurologic outcome, Surrogate marker(s) of perfusion, Survival to Discharge, ROSC

Prioritized Outcomes (1= most critical; final number = least important):

1. Favorable neurological outcome

2. Survival to Discharge


4. Surrogate markers of perfusion

Domain chairs: Gareth Buckley, Elizabeth Rozanski

Evidence evaluators: Rebekah Donaldson, Anais Gautier

Conflicts of interest: None

Search strategy: See attached document

Evidence Summary:

Study Design

Reduced Quality Factors

0 = no serious, - = serious,

- - = very serious

Positive Quality Factors

0 = none, + = one, ++ = multiple

Dichotomous Outcome Summary

Non-Dichotomous Outcome Summary

Brief description

Overall Quality

High, moderate, low,
very low, none

No of studies

Study Type





Large Effect



# Intervention with Outcome

# Control with Outcome

RR (95% CI)

Outcome: Favorable neurological outcome


Outcome: Survival to discharge


Outcome: ROSC


Outcome: Surrogate markers of perfusion


PICO Question Summary


Hyperkalemia, when severe, may be associated with CPA due to effects on the resting membrane potential of myocardial and nodal cells of the heart. Administration of calcium gluconate raises the threshold potential in these cells, normalizing the difference between the resting and threshold potentials and thus decreases the cardiac toxicity of hyperkalemia. Hyperkalemia can develop in patients in CPA, likely due to cell death and the extracellular shift in potassium caused by acidosis. This PICO question investigates the utility of calcium salts in the treatment of patients in CPA with hyperkalemia.

Consensus on science

No studies were identified in the initial literature search to directly inform the answer to this PICO question.

Several studies were identified that investigated the use of calcium in patients in CPA. The use of calcium chloride for patients in CPA with non-shockable arrest rhythms has been investigated. One case series was identified describing 4 pediatric patients with cardiac arrest during surgical procedures that all responded to intraventricular calcium chloride administration and recovered with good neurologic function.1 Plasma potassium concentrations were not measured in any of these patients.

One prospective observational study of OOH CPA in adult humans showed that the use of calcium chloride was associated with ROSC in 27/480 patients, all of which had refractory PEA.2 No patients with refractory VF or asystole achieved ROSC after administration of calcium chloride. One other observational cohort study of 529 adult human IH CPA patients and one clinical trial of 73 patients with OOH CPA with refractory asystole showed no effect of calcium chloride administration on ROSC or survival[EF1].3,4 Finally, an observational study of OOH CPA in adult humans showed significantly worse survival to hospital admission rates for patients with both asystole and PEA administered calcium compared to those not receiving calcium.5 In one experimental study in dogs, the use of calcium chloride in experimentally induced PEA led to worse survival than epinephrine and led to similar survival rates to placebo.6

After completion of the GRADE process, an additional observational study in humans was identified (very low quality of evidence, downgraded for serious indirectness and serious imprecision).7 This was a retrospective analysis of 109 patients in CPA who had documented serum potassium concentrations of > 6.5 mEq/L. The authors found that administration of sodium bicarbonate and calcium in these patients was associated with an increased frequency of ROSC for > 20 minutes, and for patients with serum potassium concentrations >6.5 and < 9.4 mEq/L, an increased frequency of survival for > 24 hours. The number of patients with serum potassium concentrations > 9.4 mEq/L was very small (7 patients) and none survived for > 24 hours, preventing statistical analysis of the effect of sodium bicarbonate and calcium on this outcome.

Treatment recommendation

We recommend against the routine administration of calcium in dogs and cats in CPA regardless of the arrest rhythm. (strong recommendation, very low quality of evidence)

We recommend administration of a single dose of 10% calcium gluconate (50 mg/kg IV over 2-5 minutes) or 10% calcium chloride (15 mg/kg IV over 2-5 minutes) in patients with documented hyperkalemia (> 6.5 mmol/L) prior to or during CPA. (strong recommendation, very low quality of evidence)

We recommend administration of sodium bicarbonate (1 mEq/kg IV) in patients with documented hyperkalemia (> 6.5 mEq/L) and pH < 7.2 prior to or during CPA. (strong recommendation, very low quality of evidence)

Justification of treatment recommendation

The clinical and experimental evidence identified to answer this PICO question did not directly address the use of calcium administration in patients in CPA with hyperkalemia, but did suggest that the use of calcium during CPR is unlikely to be beneficial regardless of the arrest rhythm. Given the known cardioprotective benefit of slow IV boluses of calcium salts in patients with hyperkalemia and the results of the Wang (2016) study identified after completion of the evidence evaluation, the committee felt that a recommendation to administer calcium to patients with documented hyperkalemia during CPR was warranted.

Knowledge gaps

The benefit of calcium in dogs and cats with naturally occurring cardiopulmonary arrest associated with hyperkalemia has not been directly evaluated, and the specific plasma potassium concentration at which intervention is warranted is also unknown. The optimal dose of calcium has not been determined.


1. Kay JH, Blalock A. The use of calcium chloride in the treatment of cardiac arrest in patients. Surg Gynecol Obstet. 1951;93(1):97-102.

2. Harrison EE, Amey BD. The use of calcium in cardiac resuscitation. Am J Emerg Med. 1983;1(3):267-273.

3. Stiell IG, Wells GA, Hebert PC, Laupacis A, Weitzman BN. Association of Drug Therapy with Survival in Cardiac Arrest: Limited Role of Advanced Cardiac Life Support Drugs. Academic Emergency Medicine. 1995;2(4):264-273.

4. Stueven HA, Thompson B, Aprahamian C, Tonsfeldt DJ, Kastenson EH. Lack of effectiveness of calcium chloride in refractory asystole. Ann Emerg Med. 1985;14(7):630-632.

5. Stueven H, Thompson BM, Aprahamian C, Darin JC. Use of calcium in prehospital cardiac arrest. Ann Emerg Med. 1983;12(3):136-139.

6. Blecic S, De Backer D, Huynh CH, et al. Calcium chloride in experimental electromechanical dissociation: a placebo-controlled trial in dogs. Crit Care Med. 1987;15(4):324-327.

7. Wang CH, Huang CH, Chang WT, et al. The effects of calcium and sodium bicarbonate on severe hyperkalaemia during cardiopulmonary resuscitation: A retrospective cohort study of adult in-hospital cardiac arrest. Resuscitation. 2016;98:105-111.


Kay 1951: Case series, 4 pediatric surgical cases that arrested, refractory to epinephrine, appeared to respond to Ca chloride (10%), 4ml

Stiell, 1995: observational cohort study, 529 CPA patients at 2 hospitals. No association between Ca administration and ROSC or S2D. Only 29 received Ca.

Harrison 1983: Prospective observational study, OOH CPA, 27/480 responded to CaCl, all had PEA, Most had profound bradycardia, idioventricular or junctional rhythms. All also received NaHCO3 and epinephrine.

Stueven, 1983: The in-field successful resuscitation rates for asystole were 8/105 (8%) in the calcium group versus 8/24 (33%) in the no-calcium group (P < .002); for EMD they were 10/63 (16%) in the calcium group versus 8/18 (44%) in the no-calcium group (P < .02). A successful resuscitation is defined as the conveyance of a patient to the emergency department with a pulse and cardiac rhythm.

Stueven, 1985: 73 patients with OOH CPA with refractory asystole, randomized to placebo or calcium chloride 10% 5ml, no difference in ROSC, no patients survived to discharge.

[EF1]There are two Steven 1985 in the ALS 15 references, I chose “lack of effectiveness…” from interpreting the sentence; apologies iim that was incorrect!

DMU Timestamp: July 13, 2023 21:18

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