Terms used in this guideline
Adults, young people and children
These are defined as:
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Adults: aged 18 years and over.
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Young people: aged 16 and 17 years. No evidence was found on transfusions specifically for young people. Recommendations for adults in this guideline will generally apply to young people as well, but healthcare professionals should use their clinical judgement on when this is not appropriate for individual patients.
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Children: aged 1 to 15 years.
Major haemorrhage
This can be defined as any of the following:
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The loss of more than 1 blood volume within 24 hours (around 70 ml/kg, or more than 5 litres in a 70 kg adult).
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A loss of 50% of total blood volume in under 3 hours.
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Bleeding in excess of 150 ml/minute in adults.
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As a practical clinical definition, bleeding which leads to:
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a systolic blood pressure of less than 90 mm/Hg or
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a heart rate of more than 110 beats per minute in adults.
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The modified World Health Organization (WHO) bleeding scale
This was used to assess bleeding in trials of platelet transfusions. Examples of bleeding at each grade are listed below:
| World Health Organization Bleeding Grade | Examples |
|---|---|
|
1 |
|
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2 |
|
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3 |
|
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4 |
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