A patient's arterial pressure has suddenly increased from -110 mm Hg to -210 mm Hg. Which could be the cause of this change?

The sudden increase in arterial pressure readings from -110 mm Hg to -210 mm Hg suggests a potential malfunction or abnormality in the dialysis set-up. The correct answer highlights three possible causes that could lead to this issue, which are all plausible in real clinical scenarios.

If the arterial needle is clotted, this can cause an obstruction to blood flow, leading to a false reading of significantly higher arterial pressures. This occurs because the transducer, sensing pressure in the line, may interpret the obstruction as increased resistance, falsely elevating the measured pressure.

Additionally, if the patient’s blood pressure has dropped—a common occurrence in dialysis patients—it may create a discrepancy in the readings, where insufficient blood flow results in abnormally high pressure readings transmitted by the transducer. This false reading can also happen due to inadequate return of blood to the machine, leading to the misinterpretation of pressure levels.

A kink in the arterial line can create increased resistance and impeded blood flow, which can also result in elevated pressure readings as detected by the transducer. This physical obstruction can lead to fluctuating or misleading pressure data as well.

The combination of any of these issues, therefore, can contribute to the significant abnormal change in arterial pressure reading, reinforcing why having multiple potential