Which of the following ECG rhythm interval measures is considered abnormal?
QTc interval 0.33 to 0.47 seconds
QT interval that varies with HR
QRS interval <0.12 seconds
PR interval 0.12 to 0.24 seconds
The Correct Answer is A
The QTc (corrected QT) interval is a measure of the time it takes for the ventricles to depolarize and repolarize during a cardiac cycle. It is corrected for heart rate (HR) to account for variations in the cardiac cycle length.
The normal range for the QTc interval varies depending on the calculation method used but generally falls within 0.36 to 0.44 seconds. In the given options, the range of 0.33 to 0.47 seconds for the QTc interval is wider than the normal range, suggesting a prolonged QTc interval, which can be indicative of a potential risk for arrhythmias, including ventricular tachycardia and torsades de pointes.
B. QT interval that varies with HR in (option B) is normal because The QT interval alone can vary with heart rate, and this is considered a normal physiological adaptation.
C. QRS interval <0.12 seconds in (option C) is normal because The QRS interval represents the time it takes for ventricular depolarization and is normally less than 0.12 seconds.
D. PR interval 0.12 to 0.24 seconds in (option D) is normal because The PR interval represents the time it takes for atrial depolarization and conduction through the AV node. The normal range is typically 0.12 to 0.20 seconds.
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 D
Explanation
The absence of palpable pulses suggests a lack of effective cardiac output, and the patient is in cardiac arrest. In this situation, immediate initiation of cardiopulmonary resuscitation (CPR) is crucial to maintain circulation and provide oxygenation to vital organs.
CPR consists of chest compressions and rescue breaths to circulate oxygenated blood to the brain and other vital organs. It is the primary intervention in cardiac arrest to provide temporary life support until advanced cardiac life support (ACLS) measures, such as defibrillation or medication administration, can be initiated.
A. Administering the prescribed Beta-Blocker in (option A) is incorrect because Administering a beta-blocker is not the initial action in a patient who is in cardiac arrest and requires immediate resuscitation.
B. Prepare for Cardioversion per hospital protocol (option B) is incorrect because Cardioversion, which is the delivery of an electric shock to the heart, may be considered in certain situations like unstable ventricular tachycardia or certain supraventricular tachycardias. However, in the given scenario, the patient is unresponsive and has no pulses, indicating cardiac arrest where CPR takes precedence over cardioversion.
C. Give 100% oxygen per non-rebreather mask in (option C) is incorrect because: While oxygenation is important, it should not delay or replace the initiation of CPR, which is the immediate priority in a patient without palpable pulses.
Therefore, the first action that the nurse should take in this scenario is to start CPR.
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