The nurse needs to estimate quickly the heart rate of a patient with a regular heart rhythm. Which method will be best to use?
Print a 1-minute electrocardiogram (ECG) strip and count the number of QRS complexes.
Calculate the number of small squares between one QRS complex and the next and divide it into 1500.
Use the 3-second markers to count the number of QRS complexes in 6 seconds and multiply by 10.
Count the number of large squares in the R-R interval and divide by 300.
The Correct Answer is C
This method, known as the 6-second method, involves counting the number of QRS complexes in a 6-second interval on the electrocardiogram (ECG) strip and then multiplying that number by 10 to calculate the heart rate per minute. The advantage of this method is that it provides a relatively quick estimate of the heart rate.
A. Printing a 1-minute ECG strip and counting the number of QRS complexes in (option A) is incorrect because it can be time-consuming and may not be practical in situations where a quick estimate is needed.
B. Calculating the number of small squares between one QRS complex and the next and dividing into 1500 in (option B) is incorrect because it is a method used to calculate heart rate, known as the "1500 method," but it is not as quick as the 6-second method and requires more time and measurement precision.
D. Counting the number of large squares in the R-R interval and dividing by 300 is another method used to calculate heart rate, known as the "300 method," but it is also less quick and less accurate for assessing heart rate in patients with regular rhythms.
It's important to note that if the heart rhythm is irregular, these methods may not provide an accurate estimate of the heart rate, and a longer monitoring period or a different approach may be necessary.
Nursing Test Bank
Naxlex Comprehensive Predictor Exams
Related Questions
Correct Answer is B
Explanation
Central venous pressure (CVP) is a measurement of the pressure in the central veins, which reflects the blood volume and right-sided cardiac function. High CVP readings may indicate fluid overload or impaired cardiac function, and intervention is necessary to address the underlying cause.
Administering IV diuretic medications can help reduce fluid volume by increasing urine output and promoting fluid elimination. By removing excess fluid, the diuretic medications can help lower the CVP and alleviate the high pressures.
The other options mentioned are not the anticipated actions for addressing high CVP:
A. Increasing the IV fluid infusion rate in (option A) is incorrect because: If the CVP is already indicating high pressures, increasing the IV fluid infusion rate would further contribute to fluid overload and exacerbate the problem. This action would not be appropriate for high CVP readings.
C. Elevating the head of the patient's bed to 45 degrees in (option C) is incorrect because Positioning the patient with the head of the bed elevated is commonly done to prevent complications such as aspiration or improve respiratory function. While it may have other benefits, it does not directly address the high CVP.
D. Documenting the CVP and continuing to monitor in (option D) is incorrect because Documenting the CVP and continuing to monitor is important for ongoing assessment and evaluation. However, in the presence of high CVP readings, intervention is necessary to address the underlying issue rather than solely documenting and monitoring.
Therefore, when a patient's CVP monitor indicates high pressures following surgery, the nurse would anticipate administering IV diuretic medications to help reduce fluid volume and lower the CVP.
Correct Answer is B
Explanation
Mean arterial pressure (MAP) is a measure of the average pressure within the arteries during one cardiac cycle. It represents the perfusion pressure that drives blood flow to organs and tissues. MAP is calculated using the formula:
MAP = Diastolic blood pressure + 1/3 (Systolic blood pressure - Diastolic blood pressure)
Blood loss, particularly in cases of significant hemorrhage, leads to a decrease in blood volume. When blood volume decreases, there is less circulating blood available to generate pressure within the arterial system. This reduction in blood volume results in decreased MAP.
Therefore, in the case of massive blood loss after trauma, the student can correlate it with a lower blood volume, which in turn leads to a lower MAP. The decrease in blood volume reduces the perfusion pressure, compromising organ and tissue perfusion
A. It causes vasoconstriction and increased MAP in (option A) is incorrect because: While vasoconstriction can occur as a compensatory mechanism to maintain blood pressure, it does not necessarily lead to an increased MAP in the context of significant blood loss.
C. It raises cardiac output and MAP in (option C) is incorrect because Blood loss typically leads to a reduction in cardiac output due to decreased blood volume. Therefore, it does not raise cardiac output and MAP.
D. There is no direct correlation to MAP in (option D) is incorrect because: There is indeed a direct correlation between blood loss and MAP. As blood volume decreases, MAP decreases as well.
Therefore, the correct correlation between blood loss and MAP is that lower blood volume lowers MAP.
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