Introduction Adequate blood pressure is essential to maintain the blood supply and function of vital organs. Measurement of blood pressure is therefore a key part of the monitoring of patients during anaesthesia and critical care. Normal' or 'acceptable' blood pressure varies with age, state of health and clinical situation.
Blood pressure is lower in late pregnancy and during sleep.
From this, you can see that a systolic pressure of 160mmHg for an elderly man or 90 mmHg for a pregnant woman may be quite normal. To judge whether any particular reading is too high or too low, we must compare the reading with the 'normal' for that patient. Techniques of measurement Rough estimates without using any equipment at all It is not possible to derive a numerical value for blood pressure without some equipment, but a crude assessment of the circulation can still be obtained. If you can feel a radial pulse the systolic blood pressure is usually at least 80 mmHg. The character of the pulse, i.e. bounding or thready, gives a further clue.