Measuring changes in heart rate and blood pressure when a patient goes from lying down to standing up can tell us if blood isn’t circulating well. Such changes can be an early sign of Shock. This is called Checking Postural (or Orthostatic) Vital Signs
- First we have the patient lie down for 5 minutes to normalize blood pressure and pulse.
- We count their heart rate (take the pulse) and take their blood pressure. Heart Rate is most accurately by listening with stethoscope (instead of feeling for a pulse at the wrist).
- We have them abruptly stand up, without sitting first. We keep them standing 2-3 minutes (staying right beside them, in case they might fall).
- We count the heart rate and take the blood pressure again
We consider their heart rate abnormal if it increases by 20% (1/5) or more. The blood pressure is abnormal if the difference between systolic & diastolic (top & bottom numbers) narrows, like 120/80 becomes 110/90, or more so if both systolic & diastolic numbers fall significantly. Note that many clinicians perform this maneuver from lying to sitting to standing. That’s more gentle for the patient, it’s important education for patients who may get dizzy when they stand, but it hides the body’s response, causing a lot of false-negatives! If they need to do this maneuver on you, diagnostically, insist you want to go from lying directly to standing.
Medicines like beta-blockers (propranolol [Inderal®], metoprolol, atenolol, etc.) will interfere with assessment of heart rate (they keep the pulse slow). We can also be fooled if patients have a poorly-functioning autonomic nervous system (which controls our vital signs), due to old age or certain uncommon conditions.