What should you do if the amplitude of the QRS complex causes the stylus to move off the paper during an ECG recording?

When the amplitude of the QRS complex exceeds the standard range, resulting in the stylus moving off the paper during an ECG recording, adjusting the machine to run at 1/2 standard is the most appropriate action. This setting reduces the sensitivity of the machine, allowing it to accommodate larger deflections without the stylus exceeding the limits of the paper.

This adjustment ensures that the QRS complex is appropriately represented on the ECG strip, giving a more accurate depiction of the heart's electrical activity. By halving the standard sensitivity, high amplitude signals are scaled down, preventing distortion or loss of critical data that could occur if the signals go off-paper.

Other options, such as adjusting the patient's position, may not adequately address the primary issue of excessive amplitude. Speeding up the paper movement also does not resolve the problem of the stylus hitting the edge of the paper, as it merely alters how quickly the information is recorded without changing the sensitivity settings. Similarly, setting the machine to run at 1/4 STD would excessively lower the sensitivity beyond what is necessary, potentially obscuring smaller but significant waves in the ECG. Thus, adjusting to 1/2 STD is the best practice to ensure a clear and accurate ECG reading.