Patient Blood Management Guidelines: Module 1

Critical Bleeding Massive Transfusion

| Background |

3.3 Early clinical assessment

Common causes of critical bleeding include trauma, gastrointestinal bleeding, ruptured aortic aneurysm, obstetric haemorrhage and surgical procedures.18 It can be difficult to recognise the early signs of blood loss. However, significant blood loss from any cause results in a sequence of physiological responses that help to maintain cardiac output and preserve blood flow to vital organs. Thus, changes in physiological and biochemical parameters can be used to recognise a critical haemorrhage.19 Reliance on systolic blood pressure alone may delay recognition of haemorrhagic shock.

The physiological response to haemorrhage may also vary with underlying conditions (e.g. cardiovascular disease), the presence of certain medications or drugs, the patient’s age and the presence of hypothermia.20

A useful classification of blood loss that may assist with the clinical assessment of the bleeding adult patient has been described by the American College of Surgeons (ACS) in their advanced trauma life support education program; this classification is shown in Table 3.1.

Management of critical bleeding should focus on early recognition of blood loss, rapid control of the source of bleeding and restoration of circulating blood volume.
Initial assessment of the bleeding patient should include evaluation of:
  • history
  • systolic blood pressure
  • heart rate
  • pulse pressure
  • peripheral perfusion
  • mental status
  • respiratory rate
  • urine output
  • haemoglobin and haematocrit
  • coagulation status
  • acid–base status
  • temperature
Table 3.1 Estimated blood loss based on patient’s initial presentation
Class of haemorrhagic shock
Blood loss (mL) Up to 750 750–1500 1500–2000 > 2000
Blood loss (% blood volume) Up to 15 15–30 30–40 > 40
Pulse rate (per minute) < 100 100–120 120–140 > 140
Blood pressure Normal Normal Decreased Decreased
Pulse pressure (mm Hg) Normal or increased Decreased Decreased Decreased
Respiratory rate (per minute) 14–20 20–30 30–40 > 35
Urine output (mL/hour) > 30 20–30 5–15 Negligible
Central nervous system/mental status Slightly anxious Mildly anxious Anxious, confused Confused, lethargic

Source: Adapted from American College of Surgeons (ACS) Committee on Trauma (2008)19
Reproduced with permission from ACS
Note: Values are estimated for a 70 kg male