'What Are My Chances?' Prognostic Tool for In-Hospital Arrest Survivors Spurs Debate

June 29, 2012

June 29, 2012 (Chicago, Illinois) — A novel scoring system intended for survivors of in-hospital cardiac arrest can predict their chances of discharge with a good neurologic outcome, concludes a report published in the June 25, 2012 issue of the Archives of Internal Medicine [1]. But an editorial accompanying their publication expresses concern that the risk-prediction tool will be used to guide premature termination of care [2].

Some of the criteria on which the prediction tool is based are obtainable only after the patient pulls through the process of resuscitation, such as how long it took, which makes the scoring tool uniquely useful for code survivors and their families, its designers say.

My concern is that use of the clinical prediction rule in a manner other than the way it was developed will lead to premature cessation of attempted resuscitation, premature withdrawal of care, and unfortunate patient outcomes.

Indeed, the scores aren't meant to guide treatment decisions but "to provide some boundaries and guidance" for providing the patient and family with more specific information," lead author Dr Paul S Chan (Mid America Heart Institute, Kansas City, MO) told heartwire .

Chan said he has "observed this many times" between physicians and patients: "When a patient has a code, the family is very anxious as to what expectations are in terms of whether the patient will survive through the hospitalization and what their likelihood of surviving intact neurologically would be. [But] physicians are oftentimes at a loss as to how to convey that information in any even semiquantitative way."

The prediction tool, which they call the Cardiac Arrest Survival Postresuscitation In-hospital (CASPRI) score, was developed from the experience of >40 000 patients successfully resuscitated at 551 hospitals participating in the AHA's Get With the Guidelines (GWTG) Resuscitation registry from 2000 to 2009.

"We're All Trying to Do the Right Thing."

The accompanying editorial from Drs Ella Huszti and Graham Nichol (University of Washington–Harborview Center for Prehospital Emergency Care, Seattle) appears mostly downbeat regarding the study. It has critical comments regarding the statistical methods used as well as--it appears to Chan--off-point discussion about pre- and periarrest variables along with apparent suggestions that the scoring system is about deciding when to terminate supportive care.

"The easiest way to reduce the large regional variation in outcome after the onset of cardiac arrest is to not attempt resuscitation of any patient or to withdraw care from all patients who seemingly have a poor prognosis," according to the editorial. But, the pair writes, that would certainly be unacceptable. "Given the limitations described herein, we urge caution to those who consider applying the rule prospectively to guide clinical practice."

Ultimately, I think the real challenge is whether risk models for cardiac arrest, myocardial infarction, heart failure, or for noncardiac conditions can be moved into the electronic age.

To heartwire , Nichol said, "We're all trying to do the right thing by improving outcomes by reducing variation in care. My concern is that use of the clinical prediction rule in a manner other than the way it was developed will lead to premature cessation of attempted resuscitation, premature withdrawal of care, and unfortunate patient outcomes."

"I can see where there may be some concern," Chan said to heartwire . "But we were very specific in the discussion to outline that we did not mean to be recommending thresholds for the termination of care." The scores are designed to provide "more patient-centered care."

And the report, he said, clearly states that the scores "offer the potential to provide physicians reliable and valuable prognostic information for discussions with patients and their families after successful resuscitation."

Disclosure: Is Transparency Enough?

Chan questioned the short editorial that seemed, he said, to put undue focus on subjects he contends are primarily outside the scope of the study. Also, he said that the editorial disclosure statement pointed to a potential author conflict of interest, given some of the editorial's content, according to Chan. And the editorial seems to wrongly suggest that the scoring system is largely about prognosticating for deciding whether to terminate care of the postarrest patient, according to Chan.

He said also that the editorial discusses the importance of preventing in-hospital arrest, "which we wholeheartedly believe is an important issue." But, he said, "It's not totally clear why that entered into the editorial to begin with, because we weren't really talking about preventing cardiac arrest." The scoring system, he and the study report point out, was derived from and verified in a population of survivors of in-hospital arrest and meant to be used in the postresuscitation setting.

That discussion about cardiac-arrest prevention, Chan says further, draws attention to the editorial's mention of a specific patient-monitoring device and its relationship to Nichol.

I always disclose everything and believe the buyer should beware.

The editorial contends that the "sole modifiable factor" included in the scoring system "was whether the patient was monitored prior to arrest." But some say that's limited in identifying patients at increased risk of arrest.

"However, novel technologies are becoming available that could reduce barriers to monitoring and early intervention at comparatively little cost (eg, ViSi, Sotera Wireless)," Huszti and Nichol write. "We encourage ongoing efforts to improve resuscitation by evaluating such new interventions rather than efforts to predict poor prognosis after its onset."

The editorial's disclosure statement reads in part, "Dr Nichol's university has a contract with Sotera Wireless," which makes novel monitoring devices, the kind that are used to detect and get the patient through cardiac arrest.

Chan told heartwire he was surprised at the editorial's mention of Sotera.

But Nichol said the editorial's discussion of arrest prevention was intentionally broader than the study report. "The larger question is, how do we reduce variation in care?" Because the scoring system was defined in the postarrest setting, which, he said, can't be considered separate from the prearrest environment, "it doesn't account for the inherent physician biases in choosing who to persevere on and ultimately resuscitate." So discussion of monitoring was appropriate, he said.

Nichol said he has no direct relationships with Sotera. "I always disclose everything and believe the buyer should beware. I have not received any cash from the company, it is not my intellectual property, I do not own any shares in the company. The university has a contract to validate part of the device, but I disclosed that. And that may be one potential solution to monitoring patients. There are other possible solutions out there."

How the Scoring Works

The group identified independently significant predictors of survival to discharge with good neurologic outcome in a derivation cohort of 28 629 patients in the GWTG registry and developed the scoring system based on them. They then applied the system to another 14 328 patients in the same registry. That validation cohort was similar to the derivation cohort in baseline features.

We were very specific in the discussion to outline that we did not mean to be recommending thresholds for the termination of care.

All were survivors of resuscitation from in-hospital arrest, 56% of them male. Excluded were about 29 000 registry patients arresting in "the emergency department, operating suites, procedure areas . . . , and postprocedural areas, because resuscitation response times, treatment, and causes of cardiac arrest differ markedly in these environments, compared with those in inpatient ward and intensive-care units--the focus of this study," the report states.

The rate of discharge with "favorable neurologic survival," defined as "absence of severe neurological deficits," with a cerebral performance category (CPC) score of 1 or 2, was 24.6% in the derivation cohort and 24.5% in the validation cohort.

The top independent predictors of that outcome were an initial arrest rhythm of ventricular fibrillation or pulseless ventricular tachycardia with a defibrillation time up to two minutes; prearrest neurological status without disability as defined by CPC score; and shorter duration of resuscitation with return of spontaneous circulation.

The others: younger age, arrest location in a monitored unit, and absence of mechanical ventilation, renal insufficiency, hepatic insufficiency, sepsis, malignant disease, or prearrest hypotension.

Mean Survival (%) to Discharge With Favorable Neurologic Outcome by CASPRI Score

Score: 0–4 5–9 10–14 15–19 20–24 25–29 30–34 35–39 >40
Survival (%) 82.6 66.6 42.0 23.1 12.3 5.2 2.1 0 0

CASPRI=Cardiac Arrest Survival Postresuscitation In-hospital

Patients were given points according to their status for each of the criteria. For example, age at least 80 years earned them four points; pulseless electrical activity as initial arrest rhythm earned six points; resuscitation duration of only five to nine minutes three points; and renal insufficiency two points.

Total point scores predicted their risk across a range of outcomes. For example, the group reports, patients in the lowest score decile (zero to nine) had a 70.7% probability of survival to discharge with favorable neurological outcome, but it was only 2.8% for those in the highest score decile (>28).

"I admire the authors' intent; I just think it needs to be considered in a thoughtful and prudent matter," Nichol said. "I think it needs to be validated in a separate population. I personally don't think it's ready for prime time yet. I look forward to the future studies that validate their work, and then perhaps it may be ready to be incorporated into actual clinical care. But I don't think we're there yet."

"The Real Challenge" Ahead

Focusing on his group's report, Chan said, "Ultimately, I think the real challenge is whether risk models for cardiac arrest, myocardial infarction, heart failure, or for noncardiac conditions can be moved into the electronic age. We need to figure out better ways to translate these models into risk scores that can be applied at the bedside."

He and his colleagues are "trying to explore ways as to whether it can be integrated into handheld tools," Chan said. "That's one of the reasons we wanted to create a model that was more personal."

Chan and coauthor Dr Harlan M Krumholz (Yale University, New Haven, CT) disclose they are supported by grants from the National Heart, Lung, and Blood Institute. Krumholz further discloses he "is a recipient of a research grant from Medtronic through Yale University." The editorial states that Nichol "is a board member of the Medic One Foundation and has received travel reimbursement from the American Heart Association and the Resuscitation Outcomes Consortium study meetings. Dr Nichol’s university has a contract with Sotera Wireless." Dr Eric J Topol (Scripps Clinic, La Jolla, CA), editor in chief of theheart.org, is on the Sotera Wireless board of directors but reports that otherwise neither he nor his center has relationships with the company.