In Norway, 3,635 people outside of hospitals underwent cardiopulmonary resuscitation (CPR) in 2022, and only 14% survived more than 30 days. During cardiac arrest, one must determine within seconds whether there are signs of life. One method is to feel for a pulse with fingers, which can be time-consuming, uncertain, and difficult. In cardiac arrest, there will be no palpable pulse, but there is a risk of misinterpreting a pulse check as if the person has a pulse, thereby delaying CPR.
Minimizing interruptions in chest compressions is crucial for effective CPR, but during pulse palpation, chest compressions must stop. Every second without chest compression is detrimental, but even a weak pulse is important to detect since CPR is performed differently depending on the presence of a pulse. A reliable method to detect a pulse is therefore vital. During cardiac arrest, a defibrillator should be attached to the patient as quickly as possible. It provides information about the patient's electrical activity but no information about blood flow. New ultrasound technology has led to a method for measuring continuous blood flow during CPR, RescueDoppler. The probe is attached to the patient's neck like a patch and continuously records blood flow.
The main objective of the study is to develop a RescueDoppler system for use on patients and test the function and clinical utility during resuscitation after cardiac arrest both outside the hospital and in-hospital. During the pilot study, we included 25 out-of-hospital cardiac arrest patients at Nordland Hospital in Bodø and St. Olavs Hospital. We also included 36 patients who had cardiac arrest at St. Olavs Hospital in Trondheim.
During the pilot project, we made changes to the data collection equipment, as well as some procedures based on feedback from healthcare personnel who used the equipment. This has made the equipment more robust and the study better suited for a multicenter study. We have also further developed the fastening mechanism for the ultrasound probe, which is attached to the patient's neck, and we are now collaborating with leading players in the field. Healthcare personnel generally report that the equipment is easy to use, that it does not take time away from resuscitation, and that they see clinical utility in the data collected when presented. The study has gathered data of great value for physiological research on cardiac arrest.
The multicenter study started on September 17, 2024. It will include cardiac arrests over the course of a year at the following hospitals: Oslo University Hospital Ullevål and Rikshospitalet, Akershus University Hospital, and Sahlgrenska University Hospital. St. Olavs Hospital will continue to include patients with cardiac arrest both in and outside the hospital, and Nordland Hospital will include out-of-hospital patients.
Sub-goals include evaluating whether the RescueDoppler probe can be correctly placed by healthcare personnel for signal registration from the carotid artery without needing to feel for a pulse, whether it can provide feedback on the quality of chest compressions, and detect spontaneous circulation earlier than current methods.
An estimated global annual incidence of death from cardiac arrest is 7-8 million cases per year, and cardiac arrest is the third leading cause of death in industrialized countries. Survival following cardiac arrest is only 10% or less, and survival dramatically decreases for every minute that passes without advanced life support. This project aims to develop RescueDoppler - a new solution for improved outcomes after cardiac arrest. Successful resuscitation after cardiac arrest depends on restoring normal electrical activity in the heart and adequate blood flow to vital organs. Presently, however, only information about the heart's electrical activity, but not blood flow, is available during resuscitation. Although defibrillators can detect, treat, and give feedback on the reappearance of normal cardiac rhythm, crucial feedback regarding the successful restoration of blood flow to the brain is missing.
Consequently, there is a need for a simple tool to assess blood flow after cardiac arrest. Cardiac ultrasound has proven to give valuable additional information during the treatment of cardiac arrest. However, Doppler measurements of blood flow in the carotid artery can be performed without interrupting resuscitation, making it an attractive alternative for hemodynamically guided resuscitation.
RescueDoppler is a new and proprietary solution for monitoring blood flow in the carotid artery in patients suffering from cardiac arrest. The system includes a small and lightweight ultrasound probe, a fastening device for attaching the probe to the neck, and proprietary software for signal analysis. The technology is operator-independent and does not require ultrasound expertise. The project's primary objective is to document the feasibility and clinical usefulness of RescueDoppler in patients with sudden cardiac arrest. Long-term goals are to offer RescueDoppler as an integrated OEM product in defibrillators from leading global manufacturers.
