Special Circumstances

Pharmacologic Interventions for Severe Hyperkalemia and Cardiac Arrest Associated with Hyperkalemia

Last Full Review: ILCOR 2025

Hyperkalemia is defined as a serum or plasma potassium level above the upper limits of normal, usually greater than 5.0 milliequivalents per liter (mEq/L). Causes of hyperkalemia include chronic kidney disease or acute kidney injury with impaired ability to excrete potassium; medications such as nonsteroidal anti-inflammatory drugs and certain antihypertensive medications; cellular release of potassium such as with burns, hemolysis, and acidosis; and endocrine disorders such as Addison’s disease. While mild hyperkalemia is usually asymptomatic, high levels (e.g., 6.5 mEq/L to 7 mEq/L or more), particularly with an acute change, may lead to life-threatening cardiac arrhythmias and muscle weakness or paralysis. Treatment of symptomatic or acute hyperkalemia with life-threatening arrhythmias typically involves the use of intravenous calcium, albuterol, insulin (with glucose) and sodium bicarbonate. Once cardiac arrest occurs, however, the benefit of these treatments is unknown. A new International Liaison Committee of Resuscitation (ILCOR) systematic review evaluates this question.

 

Evidence Summary

A 2025 ILCOR systematic review (Jessen et al. 2025, 110489) and Consensus on Science with Treatment Recommendations (CoSTR) (Granfeldt et al. 2025; Drennan et al. 2025, S72) evaluated the effects of acute pharmacological interventions for adults and children with hyperkalemia in any setting and with and without cardiac arrest.  Pharmacological interventions aimed to mitigate the harmful consequences of hyperkalemia or to lower potassium levels, compared with no intervention or an alternative intervention. The review identified few studies reporting patient-centered outcomes such as mortality. Changes in potassium levels and electrocardiogram (ECG) changes were reported by intervention.

For the outcome of potassium values in patients not in cardiac arrest, the ILCOR meta-analysis (Granfeldt et al. 2025; Drennan et al. 2015, S72) of results from eight studies (112 total participants) using insulin 8 to 12 units (plus glucose) showed an absolute reduction in serum potassium of -0.7 milliosmoles per liter (mOsm/L) (95% CI, -0.9 to -0.6 mOsm/L). Inhaled salbutamol 10 to 20 milligrams (mg) also reduced serum potassium by -0.9 mOsm/L (95% CI, -1.2 to -0.7 mOsm/L) in meta-analysis of seven studies, while intravenous (IV) salbutamol 0.5 mg plus glucose showed an absolute reduction in serum potassium of -1.0 mmol/L (95% CI, -1.4 to -0.6 mmol/L). Meta-analyses of results from three studies all showed reductions in potassium levels with salbutamol 0.5 mg IV plus insulin 10 units and glucose, salbutamol 0.5 mg IV plus insulin 10 units compared to insulin 10 units alone, and salbutamol 0.5 mg IV plus insulin 10 units compared to salbutamol 0.5 mg alone. The greatest absolute reduction in potassium levels was -1.2 mOsml/L (95% CI, -1.5 to -0.8 mOsm/L) with salbutamol 0.5 mg plus insulin 10 units and glucose. For the administration of sodium bicarbonate 50 to 390 mOsm IV, five studies with 44 total participants were included in the meta-analysis showing an absolute reduction in potassium levels of -0.1 mOsm/L (95% CI, -0.3 to -0.1 mOsm/L) (Granfeldt et al. 2025; Drennan et al. 2025, S72).

For the administration of calcium, only one study (Celebi Yamanoglu and Yamanoglu 2022, 75) with 111 participants met inclusion criteria, with the finding of no changes in non-rhythm ECG disorders. One study evaluated the use of calcium in cardiac arrest in 109 patients with a serum potassium level greater than 6.5 mEq/L measured during cardiopulmonary resuscitation (Wang et al. 2016, 105). No change in ECG rhythm was shown with the administration of calcium.

On the basis of this review, ILCOR made a weak recommendation for the treatment of acute hyperkalemia that suggests administering IV insulin in combination with glucose and/or administering inhaled or IV beta-2 agonists (Granfeldt et al. 2025; Drennan et al. 2025, S72). A weak recommendation suggests against the routine use of IV sodium bicarbonate for acute hyperkalemia. There was insufficient evidence to recommend for or against the use of calcium.

For patients with cardiac arrest suspected to be caused by acute hyperkalemia, a weak recommendation by ILCOR suggests administering IV insulin in combination with glucose. There was insufficient evidence to recommend for or against the use of IV sodium bicarbonate or calcium.

This ILCOR review (Granfeldt et al. 2025; Drennan et al. 2025, S72) was prioritized because routine use of calcium is not recommended in cardiac arrest, yet calcium is a recommended treatment for ECG changes and arrhythmias caused by hyperkalemia. The role of calcium during cardiac arrest from hyperkalemia was uncertain. Of note, all but two studies included in the ILCOR review were conducted in patients not in cardiac arrest. For acute hyperkalemia in patients not in cardiac arrest, ILCOR based the treatment recommendation on a meta-analysis of 50 patients that showed a greater reduction in potassium levels when insulin and salbutamol were combined, compared with insulin alone. An initial treatment strategy of lowering extracellular potassium levels, combined with more permanent potassium-lowering strategies, was felt to be a logical approach. The limited number of studies did not allow for specific dosing or ranking of interventions. The meta-analysis of five studies of sodium bicarbonate failed to show a reduction in potassium levels, and only one study was included that looked at calcium and ECG changes in patients without cardiac arrest. There was no signal of harm with the administration of calcium, and current guidelines recommend calcium for acute hyperkalemia without cardiac arrest. This was considered in the decision by ILCOR to not recommend against routine calcium in hyperkalemic patients without cardiac arrest (Granfeldt et al. 2025; Drennan et al. 2025, S72).

For patients with cardiac arrest associated with hyperkalemia, beta-2 agonists were not recommended since beta-adrenergic activation is already present with the administration of epinephrine, and there is a theoretical potential for harmful effects from excessive beta stimulation. The decision by ILCOR to not recommend for or against sodium bicarbonate for cardiac arrest with hyperkalemia was based on a lack of effect in cardiac arrest (in general), a lack of studies evaluating its effect in cardiac arrest with hyperkalemia and a lack of evidence showing any harm with its use. The decision by ILCOR to not recommend for or against calcium for cardiac arrest with hyperkalemia was based on several factors, including anecdotal evidence of a cardio-protective effect of calcium during hyperkalemia (Chamberlain et al. 1964, 464). However, two studies (at critical risk of bias), showed higher mortality in patients receiving calcium (Cashen 2023, 109673; Wang et al. 2016, 105). In a single study, data suggests potential harm with calcium administration in out-of-hospital cardiac arrest with pulseless electrical activity and ECG characteristics potentially associated with hyperkalemia (Vallentin et al. 2022, 150). Lastly, calcium is generally recommended against during cardiac arrest.

Insights and Implications

For the intervention of inhaled or IV salbutamol for hyperkalemia, it should be noted that salbutamol is the International Nonproprietary Name of the drug, and albuterol is the same drug but with the United States Adopted Name. In addition, it is available in the United States in inhaled (metered-dose or nebulized) form, but not in IV form. The IV form is available in Canada.

The American Red Cross Scientific Advisory Council evaluated and discussed the ILCOR systematic review and CoSTR in depth, particularly the lack of a recommendation for or against the use of calcium for hyperkalemia without cardiac arrest. It was noted that only one such study (Wang et al. 2016, 105) met inclusion criteria, and while it did not show a change in ECG rhythm, the administration of calcium and sodium bicarbonate was positively associated with sustained return of spontaneous circulation (ROSC) when serum potassium was less than 9.4 mEq/L (OR, 51.11; 95% CI, 3.12–1639.16; P= 0.01). The number of patients included in the analysis was small and further study was recommended.

Eggertsen et al. (Eggertsen et al. 2024, e67) studied the efficacy of calcium chloride and sodium bicarbonate on ROSC and short-term cardiovascular function in an animal model of hyperkalemia-induced cardiac arrest. This randomized, blinded, placebo-controlled pig study found that sodium bicarbonate administration was associated with a significant increase in ROSC (24/26, 92% versus 13/26, 50%) but there was no effect of calcium chloride on the number of animals achieving ROSC (18/26, 73% versus 18/26, 69%).

A study by Cashen et al. (Cashen 2023, 109673) showed lower rates of survival to hospital discharge among all children treated with calcium during CPR for in-hospital cardiac arrest. Calcium administration, however, was not associated with better or worse outcomes in the subgroup of children with hyperkalemia. Despite these findings, the American Red Cross Scientific Advisory Council agrees that for acute hyperkalemia with ECG changes but without cardiac arrest, the anecdotal reports of wide QRS patterns on ECG rapidly narrowing with calcium administration, the lack of rigorous studies of the immediate effects from calcium with acute hyperkalemia and ECG changes or rhythm disturbances, and the lack of any signal of harm with the use of calcium in acute hyperkalemia all support the continued suggestion to consider the use of IV calcium.

For the use of sodium bicarbonate and calcium during cardiac arrest associated with hyperkalemia, the evidence is very limited and the benefits uncertain. Sodium bicarbonate administration is considered appropriate along with standard resuscitation for life-threatening arrhythmias due to poisoning from cocaine and other sodium channel blockers, while calcium, in addition to high-dose insulin therapy and vasopressors, is recommended for calcium channel blocker toxicity (Lavonas et al. 2023, e149). In these special circumstances, the administration of sodium bicarbonate or calcium may be considered; early consultation with a toxicologist is suggested to guide management.

Opioid-Specific Advanced Life Support Therapies for Cardiac Arrest

Last Full Review: ILCOR 2025
Last Update: 2020

The incidence of opioid-associated out-of-hospital cardiac arrests (OHCAs) increased from less than 1% of OHCAs in 2000 to between 7% and 14% by 2019 (Hess et al. 2007, 200; Smith et al. 2019, 122; Wang et al. 2024, 110159). Of the approximately 105,000 drug overdose deaths in the United States in 2023, 76% involved opioids, including nearly 73,000 overdose deaths involving synthetic opioids, primarily illegally made fentanyl and fentanyl analogs (National Center for Health Statistics 2025; U.S. Centers for Disease Control and Prevention 2025). Patients with opioid-associated OHCA are typically younger than those with a presumed cardiac cause of arrest, the arrest is less likely to be witnessed, and the patients are more likely to be found in pulseless electrical activity and asystole (Dezfulian et al. 2021, e836).

Naloxone, an opioid antagonist, is effective in reversing respiratory depression from opioid overdose and in some studies has been associated with improved outcomes when administered during resuscitation. A previous systematic review (Olasveengen et al. 2020, S41) by the International Liaison Committee of Resuscitation (ILCOR) in 2020 looked at bystander naloxone administration (intramuscular or intranasal) in addition to standard cardiopulmonary resuscitation (CPR) for suspected opioid-associated cardiorespiratory arrest in the out-of-hospital setting. That review led to a recommendation to begin cardiopulmonary resuscitation CPR without delay and to use naloxone for suspected opioid-related respiratory or circulatory arrest.

A separate systematic review by ILCOR in 2015 and Consensus on Science with Treatment Recommendations (CoSTR) (Callaway et al. 2015, 36) focused on opioid-associated respiratory and circulatory arrests cared for by healthcare professionals with advanced life support. That review led to a treatment recommendation for the use of naloxone in respiratory arrest associated with opioid toxicity but fell short of a recommendation for modification of standard advanced life support in opioid-induced cardiac arrest.

 

Evidence Summary

A 2024 ILCOR systematic review (Grunau 2025, 100906) and CoSTR (Grunau et al. 2024; Drennan et al. 2025, S72) sought evidence for survival outcomes at different time points and return of spontaneous circulation (ROSC) in adults and children in any setting with cardiac arrest secondary to suspected opioid poisoning treated with any opioid-specific advanced life support-level therapy (e.g., intra-arrest naloxone or other drugs, or other intra-arrest advanced life support [ALS] interventions) for cardiac arrest resuscitation compared with standard basic life support and/or advanced cardiovascular life support management. The five studies meeting the inclusion criteria for the review all pertained to use of naloxone and sodium bicarbonate. For sodium bicarbonate use intra-arrest, one observational study (Alqahtani et al. 2019, 17) of 1,545 OHCAs with suspected drug overdose treated by emergency medical services (EMS) over an 18-year period reported that the administration of sodium bicarbonate, compared to no sodium bicarbonate, was associated with a decreased odds of survival to hospital discharge (aOR, 0.16; 95% CI, 0.08–0.31) (Grunau et al. 2024; Drennan et al. 2025 In Press, S72).

For the use of naloxone intra-arrest, three studies provided conflicting results for favorable neurological outcome at hospital discharge. The first study, published as a conference abstract (Strong et al. 2023), included 218 adult OHCAs due to presumed nonspecific overdose. The study reported that naloxone given pre-ROSC was not associated with favorable neurological outcome. A second study (Strong et al. 2024, 110263) that analyzed the same database reported that of 1807 OHCA cases with initial nonshockable rhythms not witnessed by EMS, naloxone was administered prior to vascular access and was associated with increased odds of favorable neurological outcomes (aOR, 4.61; 95% CI, 1.74–12.19). A study by Love et al. (Love et al. 2023), also published as a conference abstract, reported no statistical difference in favorable neurological outcome between patients treated with naloxone compared with those without naloxone for adult OHCA with a history of overdose or substance abuse (Grunau et al. 2024; Drennan et al. 2025, S72.

Four studies reported on the outcome of survival to hospital discharge. A study of 8,195 undifferentiated OHCAs (Dillon et al. 2024, e2429154) reported an association between naloxone administration and increased survival to hospital discharge, while Quinn et al. (Quinn et al. 2024, e249), in a matched case study (159 cases), reported naloxone was not associated with survival to hospital discharge. A third study (Strong et al. 2024, 110263) reported an association between naloxone and improved survival among EMS-unwitnessed OHCA with an initial nonshockable rhythm, while for OHCA due to presumed overdose, Strong et al. (Strong et al. 2023) did not find an association between naloxone and improved survival (Grunau et al. 2024; Drennan et al. 2025 In Press). For the outcome of ROSC, two out of three included studies (Dillon et al. 2024, e2429154; Quinn et al. 2024, e249; Strong et al. 2024, 110263) reported that naloxone was associated with improved odds, one for undifferentiated OHCA (Dillon et al. 2024, e2429154) and the second (Strong et al. 2024, 110263) for EMS-unwitnessed cases with initial nonshockable rhythms (Grunau et al. 2024; Drennan et al. 2025, S72).

The ILCOR review notes that the very low-certainty evidence regarding the benefit of any opioid-specific advanced life support (ALS) intervention was not sufficient to make a recommendation for use in cardiac arrest given the risk of interfering with other evidence-based interventions. No studies directly examined the population of opioid-associated OHCA and evidence was indirect from studies with suspected drug overdose, or undifferentiated OHCA. The 2025 ILCOR treatment recommendation states (Grunau et al. 2024; Drennan et al. 2025 , S72):

• During ALS for cardiac arrest due to opioid poisoning, there is insufficient evidence to recommend any additional opioid-specific therapies (e.g., naloxone) beyond standard resuscitation care.
• If rescuers are uncertain whether a patient with suspected opioid poisoning is actually in cardiac arrest, administration of an opioid antagonist (e.g., naloxone) is warranted. (Good practice statement)

 

Insights and Implications

This ILCOR review and recommendations are intended for healthcare professionals who are trained to ascertain pulselessness; it does not withdraw the existing treatment recommendations for bystanders without training to ascertain pulselessness and who may have difficulty distinguishing between a person with respiratory depression or apnea versus cardiac arrest.

The ILCOR treatment recommendation for bystanders states:

• We suggest CPR be started without delay in any unconscious person not breathing normally and that naloxone be used by lay rescuers in suspected opioid-related respiratory or circulatory arrest. (Weak recommendation, based on expert consensus)

 

The Red Cross guidelines for the care of opioid-associated emergencies are essentially unchanged and reflect the difficulty in recognizing cardiac arrest versus respiratory arrest in opioid poisoning.

Resuscitation of Adult and Pediatric Patients with Durable Mechanical Circulatory Support and Acutely Altered Perfusion or Cardiac Arrest

Last Full Review: ILCOR 2025

Mechanical circulatory support devices, including left ventricular assist devices (LVADs) and biventricular assist devices (BiVADs), have become indispensable in managing advanced heart failure. These devices serve various roles as:

• Bridges to transplantation.
• Therapy for patients ineligible for transplant.
• Temporary support during recovery or decision-making processes.

 

By mechanically augmenting or replacing the heart’s pumping function, mechanical circulatory support devices restore systemic circulation, thereby improving end-organ perfusion (Sen et al. 2016, 153). Despite their benefits, mechanical circulatory support devices introduce unique clinical challenges. Patients with continuous-flow LVADs often exhibit diminished or absent pulses, complicating traditional assessments of perfusion and blood pressure. Complications such as infections, particularly at the driveline site, occur in over 25% of patients within the first 2 years (Ali et al. 2020, 835). Other risks include right ventricular failure, arrhythmias and pump thrombosis. Notably, cardiac arrest in LVAD patients carries a high in-hospital mortality rate, exceeding 60% (Barssoum et al. 2022, 246). The topic of resuscitation of patients with durable mechanical circulatory support who have acutely altered perfusion or cardiac arrest was first reviewed by the International Liaison Committee on Resuscitation (ILCOR) in 2025.

 

Evidence Summary

A 2025 scoping review by ILCOR (Moskowitz et al. 2025; Drennan et al. 2025, S72) sought to identify and thematically map relevant studies of patients of any age who were receiving durable mechanical support of any kind and who develop acute impaired perfusion resulting in the need for acute resuscitation in the in-hospital or out-of-hospital setting. The search included all study types from two databases as well as the gray literature. After full text review, 32 studies were included in the review. Of the 32 included studies, 30 were case reports, eight were case series with three to ten patients, and two were cohort studies. The durable mechanical support for all studies was via a left ventricular or biventricular assist device. Thematic grouping of identified studies included:

1. Studies highlighting challenges of identifying patients with durable mechanical circulatory support devices with acutely altered perfusion and cardiac arrest. Because patients with continuous-flow LVADs do not have native heartbeats, pulselessness as well as difficulty measuring blood pressure with noninvasive electronic devices present challenges in determining if perfusion is adequate. This can lead to delays in the initiation of chest compressions and contribute to poor outcomes. In some cases, paramedics were unsure of whether chest compressions can be provided to patients using mechanical circulatory support devices. Some studies and reviews presented proposed algorithms for the resuscitation of patients with durable mechanical circulatory support.
2. Patient outcomes in mechanical circulatory support device-supported patients with cardiac arrest after performance of chest compressions versus no chest compressions. A cohort study (Barssoum et al. 2022, 246) of 578 patients with LVADs who had cardiac arrest reported higher in-hospital mortality in patients who received chest compressions than those who did not receive chest compressions (74.3% versus 55%).
3. Outcomes in mechanical circulatory support device-supported patients who have cardiac arrest and receive compressions. Across these studies, a favorable outcome was reported in 71 out of 226 (31.4%) mechanical circulatory support device-supported patients with cardiac arrest. Causes of cardiac arrest reported included device thrombus, cardiac tamponade, accidental disconnection and driveline failure.
4. Complications of chest compressions. Device dislodgement or other complications related to the function of a mechanical circulatory support device after chest compressions were not reported in any studies. It was considered and evaluated by pump function assessment, imaging, and/or autopsy in several studies. The authors of the review highlighted that the absence of reported cases of device dislodgement following cardiopulmonary resuscitation strongly suggests that the risk of such dislodgement due to chest compressions is low.

 

The evidence identified with this scoping review was considered insufficient to support a systematic review or meta-analysis. However, several good practice statements were made by ILCOR (Moskowitz et al. 2025; Drennan et al. 2025, S72):

• In patients receiving durable mechanical circulatory support who develop acutely impaired perfusion because of cardiac arrest and who are not in the immediate peri-device implantation period, we suggest performing rather than withholding chest compressions.
• When caring for patients with durable mechanical circulatory support devices who suffer acutely impaired perfusion as a result of cardiac arrest, we suggest minimizing delays in initiating chest compressions while simultaneously assessing for device-related reversible causes of acutely impaired perfusion.
• We suggest rescuers follow an algorithmic approach to concurrently assess and respond to acutely impaired perfusion in patients receiving durable mechanical circulatory support.

 

The scoping review authors describe an additional review of a scientific statement from the American Heart Association and guidance from the British Societies LVAD Emergency Algorithm Working Group (Akhtar et al. 2024, 493; Peberdy et al. 2017, e1115). The latter group recommends delaying chest compressions in LVAD patients for up to 2 minutes while efforts to restart the device are made and efforts to restart the LVAD device could occur in parallel with chest compressions as long as multiple rescuers are available.

Insights and Implications

As this ILCOR review was a scoping review, no treatment recommendations can be generated. The good practice statements made, however, are reasonable and have informed new Red Cross guidelines and algorithmic treatment. Perhaps most importantly, there was no evidence of device dislodgement with chest compressions in the studies identified, which reinforces the recommendation to provide chest compressions without hesitation when indicated. In addition, evidence suggests that patients with durable mechanical circulatory support devices in cardiac arrest who receive compressions earlier may have better outcomes. By combining assessment of device-related reversible causes of acutely impaired perfusion with initiating chest compressions, delays are minimized.

Interventions for Cardiac Arrest from Pulmonary Embolism

Last Full Review: ILCOR 2020
Last Update: 2024

Fibrinolytic drugs are an option to consider for patients in cardiac arrest due to known or suspected pulmonary embolism. Evidence to support their use is limited, with most studies in a 2020 International Liaison Committee on Resuscitation (ILCOR) systematic review not finding a difference in survival outcomes with the use of fibrinolytics compared with placebo during cardiac arrest (Berg et al. 2020, S92). Evidence to support the use of surgical embolectomy and percutaneous mechanical thrombectomy was limited to case series. Is there new evidence to support or change guidelines?

 

Evidence Summary

An evidence update (Wyckoff et al. 2022, e483) of a 2020 ILCOR systematic review (Berg et al. 2020, S92) on alterations in treatment algorithms for cardiac arrest due to pulmonary embolism or suspected pulmonary embolism identified relevant observational studies of thrombolysis with a limited number of patients and yielding divergent results. An update to the systematic review is unlikely to change current treatment recommendations.

Insights and Implications

The Red Cross guidelines have been updated to include the options of surgical embolectomy or percutaneous mechanical thrombectomy when pulmonary embolism is the known or suspected cause of cardiac arrest.

Interventions for Cardiac Arrest from Hyperthermia

Last Full Review: American Red Cross Scientific Advisory Council 2017
Last Update: 2022

Heat waves are associated with significant numbers of casualties. Both exertional hyperthermia and heatstroke can result in multi-organ failure, but in some cases, they present with cardiac arrest.

 

Evidence Summary

A 2022 triennial review of an American Red Cross Scientific Advisory Council scientific review (American Red Cross Scientific Advisory Council: Resuscitation 2022a) looked for evidence related to the management of hyperthermia-induced cardiac arrest. No relevant studies were identified in a literature search spanning from 2017 to 2022. The Resuscitation Subcouncil noted that it is not feasible to immerse a person in water and simultaneously provide cardiopulmonary resuscitation (CPR), and there is no role for a mechanical CPR device as the device cannot be submerged. Observational studies from the previous 2017 American Red Cross Scientific Advisory Council review showed an association of higher ambient heat with higher mortality, but there were no intervention assessments (Yamazaki and Michikawa 2017, 60; Kranc et al. 2021, 38). There are studies indicating that effectiveness of CPR in hot environments is diminished (Martin-Conty et al. 2020; Barcala-Furelos et al. 2020, 2019). The American Red Cross Scientific Advisory Council recommendations and guidelines remain unchanged apart from minor wording changes for clarity.

Insights and Implications

Climate change is impacting public health. A recent systematic review (Liu et al. 2022, e484) with meta-analysis looked at the effects of heat exposure (high temperatures and heat waves) on cardiovascular disease outcomes, including mortality and morbidity. Results showed that a 1º C (33.8º F) increase in temperature was positively associated with cardiovascular disease-related mortality, and the overall risk of cardiovascular disease-related mortality increased by 2.1% (RR, 1.021; 95% CI, 1.020–1.023). A 1º C (33.8º F) temperature rise was associated with a significant increase in arrhythmias and cardiac arrest, while heat waves were significantly associated with an 11.7% increase in risk of mortality (RR 1.117; 95% CI, 1.083–1.141). The mortality risk increases with increasing heat wave intensity (Liu et al. 2022, e484). Future research is needed to evaluate clinical outcomes of cooling measures during resuscitation of patients with heatstroke-induced or exertional hyperthermia-induced cardiac arrest, including veno-arterial extracorporeal membrane oxygenation.

Management of Cardiac Arrest During Pregnancy

Last Full Review: ILCOR 2015
Last Update: 2024

Cardiac arrest during pregnancy is a rare and devastating complication made worse by the potential loss of two lives. In the U.S., maternal cardiac arrest was estimated at 1 in 12,000 pregnant women hospitalized for delivery between 1998 to 2011 (Mhyre et al. 2014, 810). The most common potential etiologies for maternal cardiac arrest in this subgroup of women included hemorrhage, heart failure, amniotic fluid embolism and sepsis—with about 60% of women in this very specific subgroup surviving to hospital discharge. 

More recently, data from the National Inpatient Sample (NIS) database between 2017 and 2019 reported cardiac arrest increased to approximately 1 in 9000 delivery hospitalizations, among which 68.6% survived to hospital discharge (Ford et al. 2023, 472) and was lowest during hospitalizations with co-occurring disseminated intravascular coagulation. The incidence from these two studies does not include maternal cardiac arrests occurring in the out-of-hospital setting or maternal cardiac arrest with a gravid abdomen that is not treated with a perimortem cesarian delivery (Morrison et al. 2014, 790). In addition, there is no data on fetal survival.

The unique physiological changes of pregnancy and the need to consider both maternal and fetal survival necessitate a distinctive approach to resuscitation.

 

Evidence Summary

A 2024 scoping review (Zelop et al. 2024; Greif et al. 2024) by ILCOR sought studies evaluating any specific interventions for pregnant or up to 1-year postpartum women with out-of-hospital cardiac arrest or in-hospital cardiac arrest, compared with standard care or usual resuscitation practice. Outcomes of interest included both maternal and neonatal return of spontaneous circulation (ROSC) and survival and favorable outcome at specific intervals. The review identified eight studies that were categorized by intervention.

For left-lateral uterine displacement with supine positioning for resuscitation, a study (Dohi et al. 2017, 98) using a porcine model provided indirect data showing significantly higher coronary perfusion pressures during resuscitation with supine positioning and left lateral uterine displacement compared with left lateral tilt positioning.

For resuscitative delivery, five observational studies provided data to support performing a resuscitative delivery when ROSC does not occur early during resuscitation in a pregnant woman with a uterine size of 20 or more weeks’ gestation (Zelop et al. 2024; Greif et al. 2024). Shorter times from arrest to delivery were associated with improved maternal and neonatal outcomes, although the specific times varied across studies.

For extracorporeal life support in the setting of cardiac arrest, one retrospective analysis of data from a national registry (van den Bosch et al. 2022, 1172) and one systematic review (Naoum et al. 2020, e016072) suggested improved pregnancy and peripartum outcomes for both patient and fetus. 

The authors of the scoping review note that the existing ILCOR treatment recommendations from 2015 (Callaway et al. 2015, S84) remain unchanged and include:

• A suggestion to deliver the fetus by perimortem cesarean delivery for women in cardiac arrest in the second half of pregnancy (weak recommendation, very-low-quality evidence)
• There is insufficient evidence to define a specific time interval by which delivery should begin. High-quality usual resuscitation care and therapeutic interventions that target the most likely cause(s) of cardiac arrest remain important in this population. 
• There is insufficient evidence to make a recommendation about the use of left lateral tilt and/or uterine displacement during cardiopulmonary resuscitation (CPR) in the pregnant patient.

 

In consideration of the evidence identified by the new scoping review, two new good practice statements were made:

• Extracorporeal cardiopulmonary resuscitation may be considered as a rescue therapy for selected patients with cardiac arrest during pregnancy or in the postpartum period when conventional CPR is failing, in settings in which it can be implemented.
• Institution readiness and resuscitation education is required to accommodate the unique physiological challenges of cardiac arrest during pregnancy. 

 

Insights and Implications

Multiple research gaps were identified with this scoping review. There continues to be a lack of randomized trials of interventions, such as use of left uterine displacement, the optimal strategy for airway management during maternal cardiac arrest and which patients to consider for ECPR.