Final answer:
In burn patients, heart rate and stroke volume increase to maintain perfusion, leading to an increased cardiac output. Metabolic activity also increases to meet the demands of healing and maintaining homeostasis after the injury; hence, the correct response is b) Increased, increased, increased, increased.
Step-by-step explanation:
In patients who suffer from burns, the body's response involves a number of physiological changes. The heart rate (HR) increases as a stress response, and stroke volume (SV) may initially increase due to compensatory mechanisms, such as increased sympathetic stimulation that enhances myocardial contractility. Consequently, cardiac output (CO), which is the product of HR and SV, increases. This is important in the early phase to maintain perfusion despite fluid loss and vasodilation. However, if HR becomes excessively high, SV can decrease due to reduced ventricular filling time, eventually leading to a potential decrease in CO, as seen at rates above 160 bpm in healthy individuals. Metabolic activity often increases after a burn due to the body's increased energy demands for healing and maintaining homeostasis despite the injury. Therefore, the correct answer in relation to the changes in HR, SV, CO, and metabolic activity after a burn are Increased, Increased, Increased, Increased respectively, aligning with option (b).
An elevation in metabolic activity post-burn injury is due to enhanced metabolic rate, as the body requires more energy and resources for tissue repair, thermoregulation, and combating potential infections. Hypermetabolism is a significant factor in burn patients and is characterized by an increase in basal metabolic rate, protein and lipid catabolism, and heat production.