A nurse is interpreting a client's ECG strip. Which of the following components of the ECG should the nurse examine to determine the time it takes for ventricular depolarization and repolarization?
QRS complex
QT interval
ST segment
PR interval
The Correct Answer is B
B. The QT interval represents ventricular depolarization and repolarization. It starts at the beginning of the QRS complex and ends at the end of the T wave. The QT interval reflects the total time it takes for both ventricular depolarization and repolarization to occur. Prolongation of the QT interval can be associated with an increased risk of arrhythmias, including torsades de pointes.
A. The QRS complex represents ventricular depolarization, which is the electrical activation of the ventricles. The duration of the QRS complex provides information about the time it takes for ventricular depolarization to occur. A prolonged QRS complex can indicate abnormalities in ventricular conduction, such as bundle branch blocks or ventricular hypertrophy.
C. The ST segment represents the early part of ventricular repolarization. It starts at the end of the QRS complex and ends at the beginning of the T wave. Changes in the ST segment, such as elevation or depression, can indicate myocardial ischemia or injury.
D. The PR interval represents the time it takes for the electrical impulse to travel from the atria to the ventricles. It includes atrial depolarization, atrial contraction, and the delay at the atrioventricular node. The PR interval does not specifically provide information about ventricular depolarization and repolarization.
Nursing Test Bank
Naxlex Comprehensive Predictor Exams
Related Questions
Correct Answer is A
Explanation
A. Positive end-expiratory pressure (PEEP) is applied during mechanical ventilation to prevent alveolar collapse at the end of expiration. It helps maintain the patency of the alveoli, improving oxygenation and preventing atelectasis.
B. While PEEP can improve oxygenation by recruiting collapsed alveoli and increasing functional residual capacity, it does not directly affect the concentration of oxygen delivered by the ventilator. Oxygen concentration is adjusted separately from PEEP settings.
C. PEEP is applied at the end of expiration to maintain positive pressure in the airways and alveoli, preventing them from collapsing. It does not directly affect the delivery of air during inhalation.
D. PEEP can help prevent lung damage by maintaining alveolar recruitment and reducing the risk of atelectasis and barotrauma. However, it is not the sole factor in preventing lung damage, and other ventilator settings and strategies also play a role in protecting the lungs.
Correct Answer is A
Explanation
A Adequate fluid administration is essential before giving vasopressors to patients with hypovolemic shock. The patient’s low central venous pressure indicates a need for more volume replacement. The other patient data are not contraindications to norepinephrine administration.
B Low dose dopamine is not a contraindication to epinephrine administration.
C A sinus tachycardia is not a contraindication to epinephrine administration
D Lack of urine output is not a contraindication to epinephrine administration
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