BP difference: positional and on breathing

Two parts, chosen at the top. Positional: compares supine BP with standing BP at 1–3 minutes and, optionally, 3–10 minutes. Classical orthostatic hypotension is a sustained fall of at least 20 mmHg systolic or 10 mmHg diastolic, or standing SBP under 90 mmHg (a 30 mmHg systolic fall when the supine SBP is 140 mmHg or more); a later fall is delayed orthostatic hypotension. The heart-rate rise per mmHg of SBP fall separates neurogenic (< 0.5 bpm/mmHg) from non-neurogenic causes, and supine hypertension is graded mild, moderate or severe (≥ 140/90, ≥ 160/100, ≥ 180/110 mmHg), with the ESC 2018 syncope treatment classes and the measures for supine hypertension. On breathing: measures the inspiratory fall in systolic BP with a manual cuff or an arterial line. A fall of 10 mmHg or more is pulsus paradoxus and more than 20 mmHg is marked; with a pericardial effusion it points to cardiac tamponade, without one it lists the other causes, the conditions that can mask it and reversed pulsus paradoxus.