A patient admitted to the unit displays the following cardiac rhythm on telemetry. What is the estimated heart rate?

A. Anxiety:

Anxiety can lead to an increased heart rate due to the activation of the sympathetic nervous system. When a person is anxious, their body releases stress hormones like adrenaline, which can stimulate the heart to beat faster. This increased sympathetic activity can cause sinus tachycardia, where the heart rate is faster than normal.

B. Sleep:

While sleep can affect heart rate variability, causing fluctuations in heart rate during different stages of sleep, it typically does not cause a significant and sustained increase in heart rate like sinus tachycardia. Sleep is more likely to influence heart rate patterns rather than directly cause sinus tachycardia.

C. Fever:

Fever, especially in response to infection or inflammation, can lead to an elevated heart rate. The body's response to fever includes increased metabolic activity, which can raise the heart rate as part of the physiological stress response. Fever-induced sinus tachycardia is a common finding in individuals with infections.

D. Hyperglycemia:

While hyperglycemia (high blood sugar levels) can have cardiovascular effects over time, such as contributing to atherosclerosis and heart disease, it is not typically a direct cause of sinus tachycardia. Sinus tachycardia is more commonly associated with acute stressors like anxiety, fever, or hypovolemia (such as from blood loss).

E. Blood loss:

Significant blood loss, such as during surgery or due to trauma, can result in hypovolemia, where there is a decrease in blood volume circulating in the body. In response to hypovolemia, compensatory mechanisms kick in, including an increase in heart rate (sinus tachycardia), to maintain blood pressure and perfusion to vital organs.

To calculate how many milliliters (mL) of metoprolol 1 mg/mL solution should be administered to deliver a 5 mg IV bolus dose, you can use the following formula:

Dose (mL) = Desired dose (mg) / Concentration (mg/mL)

In this case:

Desired dose = 5 mg

Concentration = 1 mg/mL

Dose (mL) = 5 mg / 1 mg/mL = 5 mL

Therefore, the nurse should administer 5 mL of metoprolol 1 mg/mL solution per dose to deliver a 5 mg IV bolus for heart rate control.