Signs of cardiac arrest
Pro Research Analysisby 
Searched over 200M research papers
Consensus Meter
Signs of Cardiac Arrest: Key Indicators and Warning Symptoms
Abnormal Vital Signs Before Cardiac Arrest
Heart Rate, Respiratory Rate, and Blood Pressure
Abnormal vital signs are prevalent in patients before experiencing in-hospital cardiac arrest (IHCA). Research indicates that a significant number of patients exhibit abnormal heart rates (HR), respiratory rates (RR), and systolic blood pressure (SBP) 1-4 hours before the event. Specifically, heart rates ≤ 60 or ≥ 100 beats per minute, respiratory rates ≤ 10 or > 20 breaths per minute, and systolic blood pressure ≤ 90 mm Hg are common indicators. Severely abnormal signs include HR ≤ 50 or ≥ 130 beats per minute, RR ≤ 8 or ≥ 30 breaths per minute, and SBP ≤ 80 mm Hg. The presence of these abnormal signs correlates with increased in-hospital mortality .
Vital Sign Trajectories
Distinct patterns in vital sign trajectories can also predict IHCA. Five critical trajectories include low and fluctuating SBP, high and fluctuating HR, persistent hypothermia, recurring tachypnea, and low and fluctuating oxygen saturation. These patterns are associated with higher triage levels and increased mortality rates, emphasizing the importance of monitoring these vital signs closely.
Warning Symptoms of Cardiac Arrest
Common Symptoms
Warning symptoms often precede sudden cardiac arrest (SCA). Dyspnea (difficulty breathing) and chest pain are the most frequently reported symptoms, occurring in 41% and 33% of cases, respectively. Other symptoms include diaphoresis (excessive sweating) and seizure-like activity. These symptoms are more specific to SCA compared to other emergency conditions, although their sensitivity for predicting SCA is relatively low .
Ignored Symptoms
Despite the prevalence of warning symptoms, many patients tend to ignore them. Studies show that about half of the patients who experienced SCA had warning symptoms in the four weeks leading up to the event, with these symptoms often recurring in the 24 hours before the arrest. Commonly ignored symptoms include chest pain, dyspnea, and palpitations .
Prognostic Value of Symptoms
Recognizing and acting on warning symptoms can significantly impact survival rates. Patients who exhibit symptoms before cardiac arrest are more likely to achieve restoration of spontaneous circulation (ROSC) and survive to hospital discharge. Symptoms such as dyspnea, chest pain, and unconsciousness are particularly critical for early intervention and improving outcomes .
Differences in Elderly and Nonelderly Patients
Age-Related Variations
Vital signs and their predictive accuracy for cardiac arrest differ between elderly and nonelderly patients. Elderly patients tend to have lower mean heart rates, diastolic blood pressure, and shock index, but higher pulse pressure index and body temperature compared to younger patients. These differences suggest that age-specific criteria may be necessary for accurately identifying at-risk elderly patients.
Conclusion
Monitoring vital signs and recognizing warning symptoms are crucial for predicting and preventing cardiac arrest. Abnormal heart rates, respiratory rates, and blood pressure, along with symptoms like dyspnea and chest pain, are key indicators. However, the sensitivity of these signs and symptoms can vary, particularly between different age groups. Early detection and response to these warning signs can significantly improve survival rates and outcomes for patients at risk of cardiac arrest.
Sources and full results
Most relevant research papers on this topic