Which precaution should be taken when hand cranking the blood pump?

When hand cranking the blood pump, one essential precaution is to remove venous tubing from the air detector. This step is crucial because if air enters the venous line while hand cranking, it can lead to air embolism, which poses a serious risk to the patient. The air detector serves to identify any air that may have entered the blood circuit, and by disconnecting venous tubing from it, operators can ensure that they are not falsely alerted to the presence of air, enabling a smoother operation of the machine during manual cranking.

The focus is on maintaining patient safety and ensuring that the blood flow system is functioning correctly. In this context, ensuring that the air detector can accurately monitor for any unwanted bubbles is a critical safety measure during the hand-cranking process.