Comparison between 2 futility scores in comatosed survivors of out of hospital cardiac arrest in a large tertiary centre in the United Kingdom: MIRACLE2 vs NULL-PLEASE

Background

The management of patients presenting with an out of hospital cardiac arrest (OHCA) is resource intensive, and mortality remains very high. Several scoring systems have been developed to predict mortality and adverse neurological outcomes, and thus aid decision making for patients arriving to heart attack centres. Two of the most commonly used scoring systems are NULL-PLEASE (1) and MIRACLE2 (2).

Purpose

The MIRCALE2 score predicts poor neurological outcome at 6 months, as measured by Cerebral Performance Category (CPC). The NULL-PLEASE score predicts in-hospital morality. We aimed to compare both scores in predicting their primary end-points in a large tertiary centre in the UK.

Method and results

This was a retrospective analysis of 435 patient who were admitted with OHCA via the primary PCI pathway to a large tertiary cardiac centre between January 2016 and September 2020. Only comatosed OHCA survivors requiring pre-hospital ventilatory support were included. 319 patients were eligible 238 patients had complete set of data and were included in the final analysis.

The association of the primary outcome was examined using logistic regression analysis. The predictive ability of the scores for the primary endpoint was tested using AUC analysis.

In-hospital mortality was 45% (108 patients), with 53% having good neurological outcome at 6 months (CPC <3). The median MIRACLE2 score for our cohort was 5 (total score 10). The median neurological outcome measured by CPC was 2. The median NULL-PLEASE score was 2 (total 14). A ROC curve for both scores was plotted, with area under the curve at 0.73 for the MIRACLE2, and 0. 0.81 for NULL-PLEASE (figure 1 and 2). Our final analysis demonstrated a MIRACLE2 score of 5 or more had sensitivity of 67% to predict poor neurological outcome (CPC 3–5). The NULL-PLEASE, score of >3 had 74% sensitivity to predict in hospital mortality.

Conclusion

To our knowledge, this is the first study to compare the MIRCLE2 and NULL-PLEASE scoring systems. Both scores did not perform as expected in our large retrospective analysis. The NULL-PLEASE was more sensitive in predicting in-hospital mortality, although MIRACLE 2 score was easier to use as it had less variables to collect.

Funding Acknowledgement

Type of funding sources: None.

Encapsulation of human erythrocytes by growing ice crystals

In this study the interaction of human erythrocytes in suspension with a planar ice-liquid interface is investigated. Due to a repulsive van der Waals force repelling the cells from the crystal and an attractive force resulting from the viscous drag of melt flow around the cell a velocity was determined below which the cell is pushed by the growing crystal and above which it is entrapped by the solid phase. The critical velocity for erythrocytes suspended in 0.85 wt% NaCl-D2O solution can be derived from measuring the time periods of pushing and is calculated to be 1.1 microns/s at a temperature gradient of 15.3 K/mm.