An arterial catheter is inserted in the right radial artery to monitor a patient's blood pressure. Which information obtained by the nurse indicates that a complication of arterial pressure monitoring may be occurring?

Beck's triad consists of three classic clinical manifestations that are suggestive of cardiac tamponade, which is the compression of the heart by accumulated fluid or blood within the pericardial sac. The three components of Beck's triad include:
A. Muffled heart tones in (option A) are incorrect because Cardiac tamponade can dampen or muffle heart sounds due to the presence of fluid or blood around the heart, which can impair sound transmission.
B. Marked hypotension in (option B) is incorrect because Cardiac tamponade can cause decreased cardiac output, leading to hypotension, which is characterized by low blood pressure.
C. Distended jugular veins in (option C) is incorrect because Elevated venous pressure resulting from impaired filling and elevated right-sided heart pressures can lead to jugular vein distension, which is commonly seen in cardiac tamponade.
However, widening pulse pressure (the difference between systolic and diastolic blood pressure) is not typically part of Beck's triad. Widening pulse pressure is associated with her conditions such as aortic regurgitation, hyperthyroidism, or conditions involving increased stroke volume, rather than cardiac tamponade specifically.

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.