Direct pressure for external haemorrhage control. Why one finger is better than a hand and why bandages on an actively bleeding wound are really unhelpful. 1. We need to compress a bleeding wound to overcome systolic BP e.g. 120mmHg. This is equivalent to 16,000N/m2.
Remember this equation from your school maths?
If a palm 10 x 10cm is used to compress the wound (0.01m2) you will need to generate160N to stop the bleeding, which is equivalent to 16.3kg.
However if you use a fingertip 1 x 1cm to compress the wound (area reduced by a factor of 100) then you will only need to compress with 163g to stop the bleeding!
The message is to localise the bleeding point, put a gloved finger on it and press hard. The smaller the area, the more force you will be able to apply. So only use a small gauze swab, not a giant dressing. Thank you to @Malcolm_999 who taught me this many years ago!
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