Elsevier

Resuscitation

Volume 180, November 2022, Pages 128-136
Resuscitation

Clinical paper
External validation of the simple NULL-PLEASE clinical score in predicting outcomes of out-of-hospital cardiac arrest in the Danish population – A nationwide registry-based study

https://doi.org/10.1016/j.resuscitation.2022.08.009Get rights and content

Abstract

Aim

The NULL-PLEASE score (Nonshockable rhythm, Unwitnessed arrest, Long no-flow or Long low-flow period, blood pH < 7.2, Lactate > 7.0 mmol/L, End-stage renal disease on dialysis, Age ≥85 years, Still resuscitation, and Extracardiac cause) may identify patients with out-of-hospital cardiac arrest (OHCA) unlikely to survive. We aimed to validate the NULL-PLEASE score in a nationwide setting.

Methods

We used Danish nationwide registry data from 2001 to 2019 and identified OHCA survivors with return of spontaneous circulation (ROSC) or ongoing cardiopulmonary resuscitation at hospital arrival. The primary outcome was 1-day mortality. Secondary outcomes were 30-day mortality and the combined outcome of 1-year mortality or anoxic brain damage. The risks of outcomes were estimated using logistic regression with a NULL-PLEASE score of 0 as reference (range 0–14). The predictive ability of the score was examined using the area under the receiver operating characteristics (AUCROC) curve.

Results

A total of 3,881 patients were included in the analyses. One-day mortality was 35%, 30-day mortality was 61%, and 68% experienced the combined outcome. For a NULL-PLEASE score ≥9 (n = 244) the absolute risks were: 1-day mortality: 80.7% (95% confidence interval [CI]: 75.8–85.7%); 30-day mortality: 98.0% (95% CI: 96.2–99.7%); and the combined outcome: 98.4% (95% CI: 96.8–100.0%). Corresponding AUCROC values were 0.800 (95% CI: 0.786–0.814) for 1-day mortality, 0.827 (95% CI: 0.814–0.840) for 30-day mortality, and 0.828 (95% CI: 0.815–0.841) for the combined outcome.

Conclusions

In a nationwide OHCA-cohort, AUCROC values for the predictive ability of NULL-PLEASE were high for all outcomes. However, some survived even with high NULL-PLEASE scores.

Introduction

The worldwide annual incidence of emergency medical services (EMS)-treated out-of-hospital cardiac arrest (OHCA) is estimated at 30–97 individuals per 100,000 inhabitants.1 After return of spontaneous circulation (ROSC), more than half of the patients remains comatose at hospital arrival, and in this patient group, the mortality rate is ∼50%.2., 3. Clinical decision-making in patients with out-of-hospital cardiac arrest admitted to the hospital is challenging, and several scoring systems have been developed to predict survival.4 Of these, the easily calculable NULL-PLEASE futility score5 (Nonshockable rhythm, Unwitnessed arrest, Long no-flow or Long low-flow period, blood pH < 7.2, Lactate > 7.0 mmol/L, End-stage renal disease on dialysis, Age ≥85 years, Still resuscitation, and Extracardiac cause) has been validated to be predictive for early in-hospital outcomes6 and survival to discharge in smaller cohorts.7., 8. However, this simple clinical score system has not previously been tested in a nationwide setting, nor has its ability to predict long-term outcomes.

The aim of the current study was to retrospectively validate the predictive ability of the NULL-PLEASE score for both acute and long-term mortality outcomes in a nationwide setting using Danish registry data.

Section snippets

Study setting

The current study was performed in Denmark from June 1, 2001, to December 31, 2019. Denmark covers ∼43,000 km2 with a population ranging from 5.35 million in 2001 to 5.83 million in 2019. The emergency medical service includes mobile advanced life support emergency care units staffed with paramedics, nurses, and/or anesthesiologists and life support ambulances staffed with ambulance technicians and/or paramedics. The mobile emergency care units are dispatched as rendezvous with primary

Results

During the study period, 30,091 patients with OHCA had either ROSC or ongoing cardiopulmonary resuscitation at hospital arrival (Fig. 1). A total of 3,881 patients (13%) with all NULL-PLEASE score parameters available were included in the main analyses. Furthermore, 26,640 patients (89%) had a complete NULL-EASE score and were analyzed separately. Overall, in the NULL-PLEASE population, 1-day mortality was 35%, 30-day mortality was 61%, and 68% suffered from the combined outcome. In the

Discussion

In this large nationwide OHCA cohort, we externally validated the NULL-PLEASE futility score for the prediction of 1-day mortality, 30-day mortality, and the combined outcome of 1-year mortality or anoxic brain damage. We showed that higher NULL-PLEASE scores were significantly associated with all three outcomes. The NULL-PLEASE score also showed a high predictive value for all outcomes. Results were consistent when using a modified NULL-EASE score, i.e., after excluding pH and lactate values.

Conclusion

In a large nationwide OHCA-cohort, we found that increasing NULL-PLEASE scores were significantly associated with higher 1-day, 30-day mortality, and 1-year mortality or anoxic brain damage. The AUCROC values for the predictive ability of NULL-PLEASE were high for both short-term and long-term outcomes. Nevertheless, there were survivors even with very high NULL-PLEASE scores. Therefore, we propose the score as an adjunct to clinical decision-making, rather than a stand-alone prognostic tool.

CRediT authorship contribution statement

Christina Byrne: Conceptualization, Methodology, Investigation, Writing – original draft, Visualization, Project administration. Carlo A. Barcella: Conceptualization, Methodology, Formal analysis, Investigation, Writing – original draft, Visualization, Project administration. Maria Lukacs Krogager: Writing – review & editing. Manan Pareek: Writing – review & editing, Visualization. Kristian Bundgaard Ringgren: Writing – review & editing. Mikkel Porsborg Andersen: Resources, Data curation,

Acknowledgements

The study was financially supported by Danish Heart Foundation and The Danish Foundation TrygFonden. The two institutions are without commercial interests in cardiac arrest area and did not influence on study design or conduct; collection, management, analysis, or interpretation of the data; or preparation, review, or approval of the manuscript for submission.

Conflicts of interest

Dr. Christina Byrne: Speaker’s Fee: Bayer.

Dr. Jesper Kjærgaard. Research grant from the Novo Nordisk Foundation NNF17OC0028706 outside the present manuscript.

Dr. Manan Pareek: Advisory Board: AstraZeneca, Janssen-Cilag; Speaker’s Fee: AstraZeneca, Bayer, Boehringer Ingelheim, Janssen-Cilag.

For all other authors: None

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