Overall survival amongst patients transported to hospital with ongoing CPR was very poor. Application of the universal prehospital termination of resuscitation rule, in patients without obvious reversible causes of cardiac arrest, would have allowed resuscitation to have been discontinued at the scene for 39.2% of patients who did not survive.

We welcome the opportunity to reply to Dr McLean's discussion of our study [1]. We appreciate the interest in our work and the additional insights provided.Our observational study explored the patient characteristics, interventions provided and response to treatment of patients transferred to hospital with ongoing CPR. We also reported the number of transported patients that would have met the criteria for the Universal Pre-hospital Termination of Resuscitation Clinical Prediction Rule. Our study did not seek to validate this termination of resuscitation rule, as this has been done by numerous others [2,3].Our study identified that in patients without obvious reversible causes of cardiac arrest, application of the universal prehospital termination of resuscitation rule, would have allowed resuscitation to have been discontinued at the scene for 39.2% of patients who did not survive. This demonstrates a need to review termination of resuscitation practices as alternatives to the current Recognition of Life Extinct (ROLE) criteria [4] may perform better. Dr McLean's letter raises a different, though nevertheless important question of factors outside of a successful resuscitation attempt. These important questions are indeed worthy of further empirical study, though do not specifically pertain to termination of resuscitation rules.

Introduction The main objective was to present characteristics and outcome of patients without sustained field return of spontaneous circulation (ROSC) transported to hospital with ongoing cardiopulmonary resuscitation (CPR). Our secondary objectives were to investigate hospital-based interventions and the performance of the universal Termination of Resuscitation-rule (uTOR). Methods In this retrospective observational cohort study, out-of-hospital cardiac arrest (OHCA) patients arriving to the emergency department of a university hospital in Sweden during a six-year period (2010–2015) were identified using a prospectively recorded hospital-based registry. Additional data were retrieved from medical records and from the Swedish cardiopulmonary resuscitation registry. Results Among 409 patients transported with ongoing CPR, 7 survived to hospital discharge (1.7%). Hospital-based interventions against a suspected cause of arrest were attempted during ongoing resuscitation in 34 patients (8.3%), of whom 3 survived to hospital discharge. The remaining 4 survivors had spontaneous in-hospital ROSC. Survivors presented with either a shockable rhythm ( n = 4) or pulseless electrical activity ( n = 3). The uTOR identified non-survivors with a positive predictive value (PPV) of 98.4% and a specificity of 71.4% for termination. Conclusion Survival after OHCA where sustained prehospital ROSC is not achieved is rare and available in-hospital interventions are rarely utilised. No patient with asystole as the first recorded rhythm survived. The uTOR identified non-survivors with a PPV of 98.4% but showed poor specificity.