The nurse is caring for a patient whose temperature has dropped from 102.4°F to 99.4°F. The nurse notes that the patient’s face is flushed. What is the reason for this assessment finding?

Choice A reason: This is an incorrect choice because release of prostaglandins lowers the patient’s heart rate and blood pressure is not a reason why acute pain is particularly dangerous for a patient having a heart attack. Prostaglandins are inflammatory mediators that are involved in pain perception and modulation, but they do not have a direct effect on the heart rate and blood pressure. In fact, some prostaglandins may have a protective role in the cardiovascular system by preventing platelet aggregation and vasodilation.

Choice B reason: This is an incorrect choice because release of substance P narrows the airways and leads to hypoxemia is not a reason why acute pain is particularly dangerous for a patient having a heart attack. Substance P is a neuropeptide that is involved in pain transmission and modulation, but it does not have a significant effect on the airways or the oxygen level. Substance P may cause bronchoconstriction in some patients with asthma or chronic obstructive pulmonary disease, but this is not a common or serious complication of acute pain.

Choice C reason: This is an incorrect choice because release of endorphins causes dangerous elevation of blood pressure is not a reason why acute pain is particularly dangerous for a patient having a heart attack. Endorphins are endogenous opioids that are involved in pain inhibition and modulation, but they do not have a major effect on the blood pressure. Endorphins may cause a slight increase in blood pressure by activating the opioid receptors in the brainstem, but this is not a significant or harmful response to acute pain.

Choice D reason: This is the correct choice because stimulation of the sympathetic nervous system will increase cardiac workload is a reason why acute pain is particularly dangerous for a patient having a heart attack. The sympathetic nervous system is part of the autonomic nervous system that is responsible for the fight-or-flight response, which is triggered by acute pain. The sympathetic nervous system will increase the heart rate, blood pressure, and cardiac contractility, which will increase the oxygen demand and consumption of the heart. This will worsen the ischemia and injury of the myocardium, and may lead to arrhythmias, heart failure, or cardiac arrest.

Choice A reason: This is incorrect. Documenting the finding in the patient’s medical record is an important step, but not the most appropriate first action of the nurse. The nurse should first confirm the irregularity by counting the apical pulse.

Choice B reason: This is incorrect. Assessing the brachial pulse for a pulse deficit is a useful technique, but not the most appropriate first action of the nurse. A pulse deficit is the difference between the apical and radial pulse rates. The nurse should first count the apical pulse before comparing it with the radial pulse.

Choice C reason: This is incorrect. Notifying the health care provider immediately is a necessary step, but not the most appropriate first action of the nurse. The nurse should first gather more information by counting the apical pulse and determining the type and severity of the irregularity.

Choice D reason: This is correct. Counting the patient’s apical pulse for one full minute is the most appropriate first action of the nurse. The apical pulse is the most accurate way to measure the heart rate and rhythm. The nurse should listen to the heart sounds at the apex of the heart, which is located at the fifth intercostal space, left midclavicular line. The nurse should count the number of beats and note any irregularities, such as skipped, extra, or uneven beats.