Changes in certain parameters

Heart rate can go up or down or show several different changes during the course of a drug effect. Cardiac rhythm may alter, i.e. the beat become irregular with or without the average rate changing. Systolic, diastolic and mean pressure may change independently and pulse pressure may also change.

Changes may take place from different base-lines and it may be important to know BOTH the size of the change AND the value at the start. Changes may also have a different latency or a different duration; don't just concentrate on the size of the response.

Appreciate that heart rate and blood pressure may show small spontaneous changes unrelated to the effects of administered drugs. The significance of a change is important; not the statistical significance (which would need repeated determination to be estimated) but the significance in relation to the size of the change measured and the stability of the system. Thus a change of 2 mmHg in the 50 mmHg response to a pressor agent should be noted but may not be important.