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 ["9"]
Explanation
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Doseinmcg/min=2mcg/kg/min×60kg=120mcg/min
Convert this to mg/min since the concentration is in mg:
120mcg/min=0.12mg/min120 \text{ mcg/min} = 0.12 \text{ mg/min}120mcg/min=0.12mg/min
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Determine the concentration of Dopamine:
- Total amount of Dopamine: 200 mg in 250 mL of saline
- Concentration:
Concentration=200mg250mL=0.8mg/mL\text{Concentration} = \frac{200 \text{ mg}}{250 \text{ mL}} = 0.8 \text{ mg/mL}Concentration=250mL200mg=0.8mg/mL
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Calculate the pump rate in mL/min:
To find the rate in mL/min needed to deliver 0.12 mg/min:
Pumprate=Desireddose(mg/min)Concentration(mg/mL)\text{Pump rate} = \frac{\text{Desired dose (mg/min)}}{\text{Concentration (mg/mL)}}Pumprate=Concentration(mg/mL)Desireddose(mg/min)
Pumprate=0.12mg/min0.8mg/mL=0.15mL/min\text{Pump rate} = \frac{0.12 \text{ mg/min}}{0.8 \text{ mg/mL}} = 0.15 \text{ mL/min}Pumprate=0.8mg/mL0.12mg/min=0.15mL/min
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Convert the pump rate to mL/hour:
Multiply by 60 to convert from mL/min to mL/hour:
Pumprate=0.15mL/min×60min/hour=9mL/hour\text{Pump rate} = 0.15 \text{ mL/min} \times 60 \text{ min/hour} = 9 \text{ mL/hour}Pumprate=0.15mL/min×60min/hour=9mL/hour
So, you should set the pump to deliver Dopamine at a rate of 9 mL/hour.
Correct Answer is C
Explanation
The nurse should listen over both lung fields to ensure that air entry is present bilaterally, indicating that the tube is correctly positioned in the trachea. This comes after observing chest movements.
B. Using an end-tidal CO2 monitor to check for placement in the trachea in (option B) is incorrect because End-tidal CO2 monitoring can provide confirmation of correct tube placement in the trachea by detecting exhaled CO2 levels. However, it requires additional equipment and setup, which may not be readily available at the bedside or immediately accessible.
C. Observing the chest for symmetrical movement with ventilation is the initial action after placing an endotracheal tube.
D. Obtaining a portable chest radiograph to check tube placement (option D) is incorrect because Chest radiographs are commonly used to confirm endotracheal tube placement, especially for long-term confirmation or if there are concerns about placement. However, obtaining a portable chest radiograph may involve delays and is not the initial action to be taken for immediate verification.
Therefore, the best initial action by the nurse to verify the correct placement of an endotracheal tube (ET) after insertion is to auscultate for the presence of bilateral breath sounds.
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