The Assessment of Risk in Cardiothoracic Intensive Care (ARCtIC): Prediction of Hospital Mortality After Admission to Cardiothoracic Critical Care
Shahin J, Ferrando-Vivas P, Power GS, et al. Anaesthesia. 2016. 71(12):1410–1416.
Reviewers: Talia K. Ben-Jacob, MD1; Ahmed Awad, MD2
- Cooper University Hospital, Department of Anesthesiology, Division of Critical Care, Camden, NJ
- Cooper University Hospital, Department of Anesthesiology, Camden, NJ
In the United Kingdom, cardiothoracic critical care units are where the complicated postoperative cardiac and thoracic medical pathologies are managed. There are models to predict surgeon-specific patient outcome and outcome in general critical care units, there are few validated models to predict outcome after admission to the cardiothoracic intensive care unit (CTICU). In addition, the current prediction models used for other critical care populations are not applicable given the unique pathophysiology of this population.
This was a retrospective analysis of 4 years of data from CTICU admissions collected by the Intensive Care National Audit and Research Centre and entered into the Case Mix Programme. Data from the first 2 years were used to develop the models and it was validated against data from the last 2 years. Primary outcome was death before final discharge. Potential variables for the model were determined by expert clinical opinion. Location prior to admissions and reason for admission also were taken into account. Multiple tests were performed to ensure statistical accuracy and the prediction model was subsequently validated.
The researchers were able to create a prediction model from 17 002 admissions to CTICUs across the UK. Of note, the majority of admissions were for postoperative patients. The authors felt that the following model with 10 variables (creatinine, white blood count, mean arterial pressure, functional dependency, platelet count, arterial pH, age, Glasgow coma score, arterial lactate, and route of admission) would be easiest to follow with the most accuracy. The model was validated and has a satisfactory c index and Brier score.
The prediction model created by the authors has good discrimination and calibration for hospital mortality after admission to CTICU. Future research is needed to determine if this model is superior to the models designed for general critical care patients. Future models also will need to test for which intraoperative and postoperative variables can predict outcome.
This study has many positive features. It is one of the first studies to address admissions to the CTICU rather than cardiac vs thoracic surgery cohorts. The database used for the study was created from multiple centers and included a very large sample size. In addition, the database used has been previously validated. The main limitation to the study is the retrospective study design. In addition, intraoperative variables such as cross-clamp time were not included, which is important given that about 75% of all admissions were postoperative patients.