Press "Enter" to skip to content

Clinical Challenges: Hyperkalemia in the ED

Hyperkalemia is not an uncommon condition: Research shows it can occur in up to 10% of hospitalized patients. In addition, severe hyperkalemia is potentially deadly and thus often confronted and treated in the emergency department (ED).

However, one of the major problems in managing the condition in the ED is the wide variation in treatment practice across facilities.

“There is no standardization of care,” Zubaid Rafique, MD, an emergency physician at Baylor College of Medicine in Houston, told MedPage Today. “The guidelines are very non-specific because the disease state is still being defined. The only thing that everybody agrees on is that you need treatment right away if you have an arrhythmia. And when you aren’t doing something that is standard, you can’t tell if it’s working or not working. And how do you improve something that you cannot even measure?”

In the REVEAL-ED (Real World Evidence for Treatment of Hyperkalemia in the Emergency Department) observational study, Rafique and co-investigators evaluated 203 patients with hyperkalemia at 14 sites across the U.S. and found that practice patterns varied considerably. Specifically, the team found that in treating these patients 43 different treatment combinations were employed within the first 4 hours after arrival in the ED.

Rafique and his colleagues have attempted to develop algorithms — such as the Proposed Diagnostic Algorithm for Hyperkalemia Treatment in the Acute Care Setting/Chronic Care — to address the lack of uniform guidelines and consensus regarding the approach to treatment. However, getting buy-in from each of the specialties involved in treating hyperkalemia care has been problematic, he said.

“You have emergency medicine, and you have internal medicine, which cares for hospitalized patients,” Rafique explained. “Then you have cardiologists who prescribe drugs that can cause hyperkalemia. And you have nephrologists who give you referrals for hyperkalemia, and family medicine doctors who are in outpatient clinics taking care of chronic hyperkalemia. So all these people, and their societies and associations, need to be convinced how hyperkalemia needs to be treated, and put out guidelines, and that becomes difficult.”

Another factor working against the standardization of care is that the evidence supporting certain aspects of managing hyperkalemia is not supported by robust safety and efficacy data. For example, he noted, some of the main drugs used to manage acute hyperkalemia, such as albuterol and insulin, are not FDA approved for the indication — “even though we know insulin has been working for 50 years,” he said.

“So there is a lack of uniformity of treatment, a lack of widely accepted guidelines in how to treat, and yet we know that it is potentially deadly,” said another REVEAL-ED investigator, Adam Singer, vice chair of research for the Department of Emergency Medicine at Renaissance School of Medicine at Stony Brook University in New York. “Multiple studies have shown kind of a U-shaped curve that indicated that whenever the potassium is higher or lower than it should be, the mortality increases exponentially, with increases or decreases of the potassium outside the normal range.”

Left untreated, severe hyperkalemia can lead to serious cardiac arrhythmia and death. However, unless a patient has actually been referred to the ED because lab tests indicate the patient is hyperkalemic, patients can arrive in the ED with what essentially is a silent condition, Singer noted.

“So, there are no signs or symptoms that are specific to hyperkalemia,” Singer told MedPage Today. “Patients may have weakness, may be nauseous, or may have no symptoms. But potassium affects the heart’s electrical system and can cause cardiac arrest, so often the way we discover it is only because we get a lab test back. But, if we don’t suspect it we may never identify it.”

An electrocardiogram (EKG) is used to identify changes in the heart suggestive of hyperkalemia. However, Singer pointed out, in more than half of patients with high potassium levels, and even in those with extremely high levels, the EKG reading can be completely normal.

“We have a condition that is not uncommon, is hard to diagnose, and is potentially fatal,” said Singer. “So, the assumption is that the faster you treat it, the better people will do.”

In a recent study in American Journal of Emergency Medicine, Singer and co-authors reviewed approximately 115,000 ED visits at Stony Brook University Hospital during 2016 and 2017, and found that 1,033 of the patients had hyperkalemia.

Mortality and inpatient admission rates were higher in patients with hyperkalemia compared with those with normal potassium levels (8.5% vs 0.8%; and 80% vs 39%, respectively). And of those hyperkalemic patients, 884 had a second potassium level measured. Singer and colleagues found that among those patients there was a significantly lower mortality rate in those whose potassium levels had normalized compared with when it had not (6.3% vs 12.7%).

“What we showed was that the mortality among people whose potassium was normalized in the ED was cut in half, which is substantial,” Singer said. “That means it is important to identify and treat the condition rapidly.”

Thus, heightened awareness of the potential presence of hyperkalemia is essential for diagnosis, he said. According to a recent review in the European Journal of Emergency Medicine, the following serve as “red flags” for causes or risk factors for hyperkalemia:

  • Chronic kidney disease
  • Acute kidney injury
  • Heart failure
  • Diabetes mellitus
  • Severe tissue breakdown
  • Renin-angiotensin-aldosterone system inhibitors
  • Nonsteroidal anti-inflammatory drugs
  • Potassium-sparing diuretics

Singer said patients with any of these risk factors should undergo an EKG, and point-of-care testing can be considered in patients in whom hyperkalemia is clinically suspected, are at high risk for hyperkalemia, and could benefit from having treatment initiated rapidly.

“So heightened awareness, early EKG, and point-of-care testing to allow rapid diagnosis will allow you to identify the condition faster,” he said.

As for treatment, it is essentially a three-fold approach, said Rafique. If a patient has cardiac arrhythmia, the first step is the administration of intravenous calcium as a cardioprotective measure to protect against sudden death.

After that, he continued, treatment with a pharmacologic therapy such as insulin can temporarily reduce serum potassium levels by shifting the potassium into the cells. That is then followed by elimination of potassium from the body by hemodialysis, or via the use of oral potassium binders recently approved by the FDA.

Disclosures

Rafique has served as a clinical trial investigator for ZS Pharma, Inc.; has received a research grant from Relypsa; and has served as a consultant for Instrumentation Laboratory, Relypsa, and ZS Pharma, Inc.

Singer has served as a consultant and clinical trial investigator for ZS Pharma, Inc. and has served as a consultant for Abbott Point of Care, Alere, and Janssen.

Source: MedicalNewsToday.com