Overview
The goal of this study is to describe the population of patients presenting after out of hospital cardiac arrest with occult perfusion, defined as a patient without a palpable pulse but with some evidence of pulsatile arterial flow. The main questions it aims to answer are:
- To measure the prevalence of patients of patients presenting to the emergency department after out of hospital cardiac arrest with occult perfusion
- To measure the association between occult perfusion and survival
- Compare survival between patients with occult perfusion that were treated as pulseless by ACLS interventions vs those treated as hypotensive
Researchers will describe the percentage of out-of-hospital cardiac arrest presenting to the emergency department without a pulse but with occult perfusion. Researchers will also compare survival endpoints (ROSC, Survival to hospital Admission, and Survival to Hospital Discharge) in pulseless patients with occult perfusion treated with ACLS interventions only and pulseless patients with occult perfusion treated as if they had pulsatile arterial flow.
Participants will undergo resuscitation based on decisions by the clinical team who incorporate echo and/or vascular ultrasound during the first three rounds of CPR. The resuscitation will continue until the patient demonstrates return of spontaneous circulation or until the clinical team halts resuscitative efforts due to futility.
Description
This is a multi-center, prospective, observational trial involving sites across the United States and Canada. Patients having suffered an out of hospital cardiac arrest will be enrolled through the emergency department either presenting in cardiac arrest with ongoing CPR or having been resuscitated en-route but re-arresting shortly after arriving in the emergency department.
Patients will undergo any echocardiography or vascular ultrasound during the resuscitation at the discretion of the clinical team and based on institutional protocols. The clinical team will be unblinded to any aspect of the resuscitation, including the echo or vascular ultrasound images. Clinical interventions during the pause in CPR will be classified as ACLS interventions for cardiac arrest or non-ACLS interventions for occult perfusion. ACLS interventions include interventions for cardiac arrest such as bolus epinephrin or CPR. Non-ACLS interventions for occult perfusion include interventions for patients with profound hypotension such as continuous adrenergic agents or halting CPR to check a blood pressure.
Patients will be determined to have demonstrated occult perfusion based on blinded review of the patient data, ultrasound images, and vascular images.
Adjudicated Echo Image Review - Recorded cardiac images blinded to all patient and sonographer information will be reviewed by research staff to identify if a) cardiac activity is present and b) organized cardiac activity is present. Cardiac output will be measured as fractional shortening of the left ventricular chamber. Images will be reviewed separately by expert reviewers blinded to all patient information with adjudication by a third when there is disagreement.
Adjudicated Vascular Image Review - Recorded vascular images blinded to all patient and sonographer information will be reviewed by research staff to identify if arterial pulsations are visible. Measurements on the B-mode imaging will include a) artery diameter (superficial to deep) b) artery diameter (side to side) c) depth of artery from skin surface and d) area of the artery cross section at peak systole and peak diastole. The pulsatile index will be calculated as the ratio of the maximal artery diameter during a single pulsation (superficial to deep) to the minimal artery diameter during a single pulsation(superficial to deep). Images will be reviewed separately by expert reviewers blinded to all patient information with adjudication by a third when there is disagreement.
Patients will be classified as demonstrating occult perfusion with the following findings:
- organized cardiac activity by echo determined to be sufficient to produce an arterial pulse
- pulsatile arterial flow visible on vascular ultrasound determined to be significant
The study has a number of pre-determined study end points that are observational and associative in nature. They include the following:
- Assessment of ECG interpretation accuracy based on comparison of expert review interpretation of ECG and initial clinical interpretation
- Exploratory assessment of number of patients treated as cardiac arrest with bolus EPI and CPR that are determined to be occult perfusion better treated with non-ACLS intervention such as stopping CPR and starting continuous adrenergic agents. The methodology for this is not described in full but will involve a modified Delphi of patient data to determine appropriate categorization.
Eligibility
Inclusion Criteria:
- Patients presenting following out-of-hospital atraumatic cardiac arrest
Exclusion Criteria:
- Resuscitation ended due to end-of-life decisions
- Documented allergy to ultrasound gel
- Technical malfunction of ultrasound machine during imaging that prevents use
- Ultrasound machine unable to record images
- Cardiac Ultrasound not performed during first, second or third pause in CPR AND vascular Ultrasound not performed during first, second or third pause in CPR
