Hypotension, low BP, fall of BP
Dr KK Aggarwal
President Heart Care Foundation of India
Former Tamil Nadu chief minister and DMK patriarch M Karunanidhi was shifted to Kauvery Hospital in the early hours of Saturday after his blood pressure dropped. His condition is now stable.
Hypotension or low BP definition
Hypotension may be
- Absolute (systolic upper blood pressure <90 mmHg; mean arterial pressure <65 mmHg)
- Relative (a drop in systolic upper blood pressure >40 mmHg)
- Orthostatic (>20 mmHg fall in systolic pressure or >10 mmHg fall in diastolic lower pressure with standing)
- Profound (drug vasopressor-dependent).
Not every patient who has hypotension has shock (chronic hypotension, drug-induced hypotension, autonomic dysfunction, vasovagal syncope, peripheral vascular disease).
Hypotension with shock
Shock is defined as a state of cellular and tissue hypoxia due to reduced oxygen delivery and/or increased oxygen consumption or inadequate oxygen utilization.
This most commonly occurs when there is circulatory failure manifest as hypotension (ie, reduced tissue perfusion).
“Undifferentiated shock” refers to the situation where shock is recognized, but the cause is unclear.
Four classes of shock are recognized
Distributive (septic shock, systemic inflammatory response syndrome, neurogenic shock, anaphylactic shock, toxic shock, end-stage liver disease, endocrine shock)
Cardiogenic (heart attack, atrial and ventricular arrhythmias, valve or ventricle septal rupture)
Hypovolemic (hemorrhagic and nonhemorrhagic fluid losses)
Obstructive (pulmonary embolism, pulmonary hypertension, tension pneumothorax, constrictive pericarditis, restrictive cardiomyopathy)
Clinical classification
Warm shock (warm hands): sepsis, anaphylaxis
Cold shock (cold hands) : heart attack, embolism, hypovolemic
