Author Question: Which of the following statements best describes the effects of positive-pressure ventilation on ... (Read 139 times)

NClaborn · **on:** Jun 25, 2018

Which of the following statements best describes the effects of positive-pressure ventilation on cardiac output?

a. Positive-pressure ventilation increases intrathoracic pressure, which increases venous return and cardiac output.
b. Positive-pressure ventilation decreases venous return, which increases preload and cardiac output.
c. Positive-pressure ventilation increases venous return, which decreases preload and cardiac output.
d. Positive-pressure ventilation increases intrathoracic pressure, which decreases venous return and cardiac output.

Question 2

A patient's bedside ECG strips show the following changes

increased PR interval; increased QRS width; and tall, peaked T waves. Vital signs are T 98.2 F; HR 118 beats/min; BP 146/90 mm Hg; and RR 18 breaths/min. The patient is receiving the following medications: digoxin 0.125 mg PO every day; D51/2 normal saline with 40 mEq potassium chloride at 125 mL/hr; Cardizem at 30 mg PO q8h; and aldosterone at 300 mg PO q12h. The physician is notified of the ECG changes. What orders should the nurse expect to receive?

a. Change IV fluid to D51/2 normal saline and draw blood chemistry.
b. Give normal saline with 40 mEq of potassium chloride over a 6-hour period.
c. Hold digoxin and draw serum digoxin level.
d. Hold Cardizem and give 500 mL normal saline fluid challenge over a 2-hour period.

jlaineee · **Reply #1 on:** Jun 25, 2018

Answer to Question 1

D
Positive-pressure ventilation increases intrathoracic pressure, which decreases venous return to the right side of the heart. Impaired venous return decreases preload, which results in a decrease in cardiac output.

Answer to Question 2

A
The electrocardiographi c (ECG) changes are most consistent with hyperkalemia. Removing the potassium from the intravenous line and drawing laboratory values to check the potassium level is the best choice with the least chance of further harm. Digoxin toxicity can be suspected related to the prolonged PR interval, but hyperkalemia explains all the ECG changes. The patient is not hypotensive or bradycardic, so holding the Cardizem is not indicated.