Pulse rates may be determined by all of the following methods except:

Each option describes a different method of determining pulse rates, but one stands out as inappropriate.

Listening to the heart with a stethoscope is a common practice in clinical settings, allowing for the direct observation of heart sounds and rhythm, which can aid in determining pulse rates. Similarly, utilizing a pulse oximeter provides a non-invasive way to measure the oxygen saturation levels in the blood and can also give readings of heart rate.

Analyzing an electrocardiogram (ECG) is another reliable method for assessing the heart's electrical activity, which directly reflects heart rate.

However, multiplying the respiration rate by 4 does not provide a clinical or physiologically accurate measure of pulse rate. While respiration and heart rates are often related, the two do not have a fixed ratio that can be applied across different individuals or situations. Each person's respiratory and heart rates can vary independently, making this method unreliable for determining pulse rates. Therefore, this option does not accurately describe a valid technique for measuring heart rate.