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Every so often I see people reassured when actively bleeding patients have a systolic BP of 100. To get a ballpark multiply their MAP by 80 and then divide that by 2000 (a squeezed shut systemic vascular resistance in stupid units - dynes.sec/cm5)
Eg BP 100/60 MAP = 72.
x 80 = 5760
/ 2000 = 2.88L/min
HR of 150 means stroke volume of 19ml when normal is 60-100ml
x 80 = 5760
/ 2000 = 2.88L/min
HR of 150 means stroke volume of 19ml when normal is 60-100ml
These patients are peri peri peri arrest and they need blood that second, and they scare me tbh, and the number of times Iâve seen it handed over âbut theyâre okay their BP is stableâ and 
Other example that will scare you and you can see how it happens. Hx of bleeding, Young woman.
BP 90/50 HR 120 âanxiousâ
MAP 60
60x80 = 4800, divide it by 2000 = 2.4L/min cardiac output and stroke volume of 20ml. Lost well over half blood volume!!!!!!!!
BP 90/50 HR 120 âanxiousâ
MAP 60
60x80 = 4800, divide it by 2000 = 2.4L/min cardiac output and stroke volume of 20ml. Lost well over half blood volume!!!!!!!!
Please do not get reassured by BP in young patients, they compensate by super squeezing their peripheral circulations with astronomical adrenaline, and we take it away when they are anaesthetised hence why even
Ketamine can provoke a crash on induction. Ballparking these numbers can help you remember how sick they really are. Usual vascular resistance is 800-1200 http://dynes.sec.cm ^5 but obviously much higher in extremis!
