Final answer:
During CPR, cardiac output is maintained through manual chest compressions that aim to imitate the natural heartbeat to supply blood to key organs. The effectiveness is influenced by the compression technique and the physiological state of the individual.
Step-by-step explanation:
Cardiac output (CO) is the amount of blood the heart pumps through the ventricles per minute. During cardiopulmonary resuscitation (CPR), the heart is manually compressed, which aims to restore a minimal flow of blood to vital organs, especially the brain to prevent irreversible damage. Properly performed, CPR involves rapid compressions at a depth of at least 5 cm and a rate of 100 compressions per minute. The technique presses on the sternum between T4 and T9 vertebrae, manually compressing the heart to push blood into the systemic and pulmonary circuits. This imitates the natural function of the heart, albeit less efficiently.
Factors influencing CO during CPR include the proper technique, frequency of compressions, and the physiological state of the individual, such as body temperature. Hyperthermia can increase the heart rate (HR) and strength of contraction, potentially affecting resuscitation efforts. Conversely, hypothermia slows the HR and contraction strength, which may impact the effectiveness of CPR.
Stroke volume (SV) is typically lower during CPR than during normal heart function due to the artificial nature of the compressions. The correlation between HR and cardiac output that exists in physiological conditions is altered during CPR. The primary goal is to maintain a flow to vital organs rather than perfectly replicate natural cardiac function.