Tables cardiac responses

Loss of plasma volume leads to a decrease in MAP. Baroreceptors located in the aortic and carotid sinuses detect this fall in MAP and elicit reflex responses that include an increase in the overall activity of the sympathetic nervous system. Sympathetic stimulation of the heart and blood vessels leads to an increase in cardiac output (CO) and increased total peripheral resistance (TPR). These adjustments, which increase MAP, are responsible for the short-term regulation of blood pressure. Although increases in CO and TPR are effective in temporary maintenance of MAP and blood flow to the vital organs, these activities cannot persist indefinitely. Ultimately, plasma volume must be returned to normal (see Table 19.1). 

As increases in cardiac troponin detect any form of myocardial injury, nonischemic mechanisms of injury are also responsible for cardiac troponin release from the heart, causing increases in circulating troponin. Table 5-3 shows a list of potential etiologies that have been responsible for increases in non-ischemic damage to the heart. Thus, whenever cardiac troponin is monitored, it is important to follow the serial pattern of a rising or a falling pattern of the biomarker. An increased cTn pattern that remains relatively unchanged and is not indicative of this serial trend is likely not an MI. 

The three main diuretic classes are thiazide, loop, and potassium-sparing diuretics (Table 10-1). Thiazide diuretics are considered one of the first-line agents for the treatment of HTN. Acutely, thiazide diuretics lower blood pressure by inhibiting sodium chloride cotransporters in the ascending loop of Henie and distal tubule, increasing sodium excretion and causing diuresis. The reduction in plasma volume decreases cardiac output and consequently reduces blood pressure. However, with continued therapy, the plasma volume returns to pretreatment level and there is a decrease in peripheral vascular resistance, which is responsible for the long-term anti hypertensive effects. The most common indication for thiazide diuretics is HTN. 

TABLE 12—1. Responsibilities of Cardiac Resuscitation Team Members... 

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