What factor can change impedance readings in patients undergoing monitoring?

The presence of anemia or pneumonia can indeed impact impedance readings in patients undergoing monitoring. Impedance monitoring often assesses the volume status and fluid levels in patients, particularly those with heart failure. Anemia can alter the blood's electrical conductivity due to changes in hemoglobin levels, affecting the overall impedance readings. Similarly, pneumonia may contribute to changes in fluid distribution within the body and potentially impact the vascular and pulmonary systems. These conditions can lead to variations in body composition and fluid status, directly influencing impedance measurements through alterations in the electrical properties of the tissues being monitored.

Other factors, such as body temperature variations, can also affect impedance readings, yet they are generally less impactful compared to the significant physiological changes caused by anemia and pneumonia. The time of day may influence the physiological state of an individual, but it is less likely to cause notable changes to impedance directly. Regular physical exercise can lead to acute changes in body fluid distribution, but typically, its lasting influence on impedance readings is minimal compared to the effects associated with conditions like anemia or pneumonia.