Understanding the Enemy: In-Hospital Cardiac Arrest in COVID19

The study obtained data from 68 hospitals across the US and enrolled  5,019 patients. Participants enrolled were 18 or older with confirmed COVID-19, with the primary measure looking at cardiac arrest within 14 days of admission to an intensive care unit and in-hospital mortality.

The numbers were staggering. Of the 5019 patients admitted with COVID 19, 701 (14%) sustained an in-hospital cardiac arrest. Of those 701 patients, 400 (57.1%) received cardiopulmonary resuscitation. 135 of the 400 patients (33.8%) who received cardiopulmonary resuscitation achieved return of spontaneous circulation. 48 (12%) patients survived to discharge, but only 28 (7%)) were discharged with average or mild neurological impairment. 

The mean age of patients who had an in-hospital cardiac arrest was 63 and typically had more comorbidities and were often admitted to smaller hospitals with fewer ICU beds. The mean age of patients that received resuscitative efforts was 61. Survival to discharge differed dramatically, with 21.2% of patients younger than 45 years survived compared to 2.9% (1/34) of those aged 80 or older. 

The most common initial rhythm was pulseless electrical activity (49.9%,199/400) and asystole (23.8%, 95/400). 

In the patients that did receive resuscitative efforts, Epinephrine was the most commonly used treatment during cardiopulmonary resuscitation (81.0%, 324/400), followed by defibrillation (18.5%, 74/400). The median duration of cardiopulmonary resuscitation was 10 minutes (interquartile range 5-18). Younger patients received cardiopulmonary resuscitation for a longer duration than older patients (median 13 minutes (interquartile range 7-20) in patients younger than 45 years compared with 7 minutes (4-14) in patients aged 80 or older).

The authors of the article identified three important implications from their findings. 

1. A large percentage of critically ill patients that were admitted to the hospital would suffer a cardiac arrest.
2. The data set was able to help identify important patient and hospital risk factors, thereby highlighting patients that may need closer monitoring or earlier goals of treatment discussions
3. Information on survival could guide end of life care discussions with critically ill patients and their families as the data helped characterize the likelihood of survival in critically ill COVID-19 patients.

Strengths of their study:

1. Large study with 5019 patients
2. Data were obtained from chart review at 68 hospitals
3. All patients were followed until death, hospital discharge, or a minimum of 30 days from admission to the intensive care unit. 
4. Collection of neurologic status at hospital discharge among survivors.

Limitations:

1. Data on the cardiac rhythm of patients who did not receive resuscitation were not available
2. Unable to obtain data from the timing of initial treatment such as chest compressions or defibrillation. This made assessing the quality and timeliness of resuscitation, which could have been compromised from personnel donning PPE, could have contributed to poor outcomes.
3. The data was collected on patients admitted between 4 March and 1 June 2020, which might not reflect current trends.
4. The true cardiac arrest numbers may have been underestimated as patients were only followed for 14 days after admission to the intensive care unit.