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
In this scenario, the patient's signs and symptoms suggest a state of shock, which can be caused by various factors, such as hypovolemia, cardiac dysfunction, or systemic vasodilation. The first priority in managing a patient in shock is to ensure adequate oxygenation and tissue perfusion. Administering oxygen at 100% per non-rebreather mask helps improve oxygen delivery to the tissues and supports vital organ function.
A. Placing the patient on a continuous cardiac monitor in (option A) is incorrect because it is an important step to monitor the patient's heart rhythm and identify any abnormalities. However, providing oxygen should take priority to address the potential hypoxemia and tissue hypoperfusion.
C. Inserting two 14-gauge IV catheters in (option C) is incorrect because it is crucial for establishing large-bore access for fluid resuscitation and medication administration. While it is an important step, addressing oxygenation takes precedence.
D. Drawing blood to type and crossmatch for transfusions in (option D) is incorrect because it is an important step in managing a patient in shock who may require blood products. However, ensuring adequate oxygenation through oxygen administration is the immediate priority.
Therefore, the nurse should act first on the order to administer oxygen at 100% per non-rebreather mask to support the patient's oxygenation and tissue perfusion.
Correct Answer is D
Explanation
In the compensatory stage of shock, the body initiates various mechanisms to maintain perfusion to vital organs and restore homeostasis. Activation of the renin-angiotensin system is one of the compensatory responses. The decreased blood flow and oxygen delivery to the kidneys stimulate the release of renin from the kidneys. Renin acts on angiotensinogen, converting it into angiotensin I, which is further converted to angiotensin II by the action of angiotensin-converting enzyme (ACE). Angiotensin II is a potent vasoconstrictor and also stimulates the release of aldosterone, leading to sodium and water retention. These mechanisms aim to increase blood pressure and cardiac output and restore fluid balance.
A. The initial stage of shock in (option A) is incorrect because it is characterized by inadequate tissue perfusion and the activation of various compensatory mechanisms, including the release of stress hormones. However, the renin-angiotensin system is not specifically mentioned as activated in this stage.
B. The progressive stage of shock in (option B) is incorrect because it occurs when compensatory mechanisms fail to maintain adequate perfusion, leading to worsening hypoperfusion and organ dysfunction. The renin-angiotensin system continues to be activated during this stage, but it is primarily associated with the compensatory stage.
C. The refractory stage of shock in (option C) is incorrect because it is the stage of severe and prolonged hypoperfusion, where organ failure becomes irreversible. The renin-angiotensin system may still be activated, but it is not the primary focus of this stage.
Therefore, the activation of the renin-angiotensin system occurs during the compensatory stage of shock.

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