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
These patients are peri peri peri arrest and they need blood that second, and they scare me tbh, and the number of times I’ve seen it handed over “but they’re okay their BP is stable” and 😱
Other example that will scare you and you can see how it happens. Hx of bleeding, Young woman.

BP 90/50 HR 120 “anxious”
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 dynes.sec.cm^5 but obviously much higher in extremis!

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More from @Jopo_dr

16 Oct
#worldanaesthesiaday earliest anaesthetic on record is alcohol. Mixed with a variety of herbs, records for it exist from more than 2 millennia BC. Common additions were cannabis, opium (grown in Mesopotamia across similar time period before spreading to Europe several hundred
Years AD). The other common addition was mandrake. These had a lot of associated superstition as their roots resemble human figurines and were considered to scream when pulled up/kill the uprooter.
They contain huge amounts of various alkaloids but chiefly atropine, which when given in high doses is anaesthetic in effect, amongst hundreds of other hallucigenic compounds mostly poisonous in the doses they were able to extract.
Read 10 tweets
26 Sep
This really spoke to me. Currently all emphasis is on individuals to regulate shift changes, sleep - but because 'nature cannot be fooled', it is biologically implausible individuals can fully compensate. Somehow power naps, shift design, rest facilities have to be considered.
We are not selecting to work 8-8 daytime on a sunday and 8-8 on a Tuesday. That's an employer/scheduling design. We need to cover things 24/7 but we know circadian physiology affects carers and patients. So being clever people, scientists,can consider ways to reduce inevitable.
Like yeah, can all be stiff upper lip blah blah, but actually it's better for patients, better for us, stops us getting sued for causing accidents tired (so many legal cases now), and when we crash & die on phone to spouses en route home from a nightshift like many anaesthetist
Read 4 tweets
26 Sep
I actually think it is Public Health concern that non scientifically trained journalists are constantly amassing poor evidence about covid and other health issues. Why is it not mandatory that to cover these areas, one should have a qualification in scientific method.
There are even graduates of Science Communication Masters degrees for example from Imperial College London (hi guys!). Journalists know what to do with sources and eyewitnesses to an event. many of them wouldn't be expected to know details about stats, study design, sampling bias
but continuously, poor science is being given headline news. Not only is it a public health concern, it is eroding trust in the profession. And it isn't just covid. There was a recent furore about coffee drinking in pregnancy causing miscarriages.
Read 7 tweets
26 Sep
Does anyone else feel covid is a sympathetic nervous system bonfire? It would explain the high respiratory drive, high levels of sedation needed, altered renal perfusion, tachycardia/cardiac dysfunction, post viral autonomic syndromes as reported and most of all
High alpha adrenergic activity increases pulmonary vascular impedance and reduces chest wall compliance. Sympathetic fibres innervate lung densely at larger central vessels and decline towards periphery
They use noradrenaline. (Important to recognise that sympathetic action at nerve terminals is usually locally effecting only - systemic is via adrenals). It would also fit with interactions with ACE/angiotensin II.
Read 6 tweets
25 Sep
OOO watching RSI sequence on The Fall. Critique coming.
BP 60 systolic in a haemorrhaging patient and they've just had 1L NaCL%. No.
Fast bleep the surgeons, None of their need a CT shite. LOL SO ACCURATE.
Read 15 tweets
25 Sep
So I listened to such a good ICS podcast about vasopressors and how we aren’t noradrenopaenic but vasoplegic. To my surprise I actually think we are noradrenopaenic? The sympathetic nervous system seems to retract from inflamed sites.
As in I genuinely think we might be! Sympathetic fibres get repulsed from spleen and vessel muscle When cytokines are raging. Did anyone else know this? I did not know this. The rheumatologists probably do. It’s meant to allow high systemic catecholamines without mass drama.
Exhibit a) you see?! Noradpaenic Image
Read 5 tweets

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