Define Assessment & Management of Blood Loss. Describe its management and grading.

Estimating Blood Loss

Managing haemorrhage begins with estimating blood loss and recognising its severity. Total blood volume is about 70 mL/kg in adults (~5 L). Loss is estimated from swab weighing, suction volumes, the surgical field, and the physiological response — tachycardia and a narrowed pulse pressure appear early, with hypotension a late sign (young patients compensate until they suddenly decompensate).

Management of Haemorrhage

Management follows resuscitation principles: large-bore IV access, fluids/blood to restore volume, control the bleeding source, and monitoring (including cross-match and coagulation). Warmed fluids and blood, and attention to temperature and calcium, are important. Restore oxygen-carrying capacity (red cells) and haemostasis (FFP, platelets, cryoprecipitate) as needed.

Massive Transfusion

Massive transfusion (e.g. Replacing the patient’s blood volume in 24 hours, or rapid large-volume transfusion) requires a protocol: giving red cells, FFP and platelets in balanced ratios to prevent dilutional coagulopathy, plus cryoprecipitate/fibrinogen and tranexamic acid. Its complications — hypothermia, hypocalcaemia (citrate), hyperkalaemia, acidosis and coagulopathy (the ‘lethal triad’ of hypothermia, acidosis and coagulopathy) — must be actively prevented and treated.

Grading the Severity of Haemorrhage

It is useful to grade acute blood loss by its physiological effects, because the signs guide the urgency of resuscitation. Small losses of up to around fifteen per cent of blood volume are usually well tolerated with little more than mild tachycardia; as loss increases towards a third of the blood volume the tachycardia becomes marked, the pulse pressure narrows as diastolic pressure rises with vasoconstriction, and the patient becomes anxious; only when loss exceeds this does frank hypotension appear, and beyond about forty per cent the patient is severely shocked with a depressed conscious level. Recognising that the compensated patient with a normal blood pressure but a rising heart rate and narrow pulse pressure is already significantly hypovolaemic is the key to intervening before sudden decompensation.

Restoring Oxygen Delivery & Haemostasis

The two goals of resuscitating a bleeding patient are to restore oxygen delivery and to secure haemostasis, and these require different interventions given in parallel with surgical control of the bleeding source. Oxygen delivery depends on an adequate circulating volume and enough red cells to carry oxygen, restored with balanced crystalloid initially and with red cells as loss becomes significant; haemostasis depends on adequate clotting factors, fibrinogen and platelets, replaced with plasma, cryoprecipitate and platelet concentrates and supported by tranexamic acid, while hypothermia and acidosis — which themselves impair clotting — are corrected. Balancing these while the surgeon controls the source is the essence of managing major haemorrhage.

Tachycardia precedes hypotension — blood pressure falls late.

• Blood volume ~70 mL/kg (~5 L adult); estimate loss from swabs/suction/field + physiology.
• Tachycardia & narrow pulse pressure early; hypotension late (compensation then sudden decompensation).
• Manage: large-bore access, restore volume (fluids/blood), control source, monitor, warm, watch calcium.
• Massive transfusion protocol: balanced red cell/FFP/platelet ratios + cryoprecipitate + tranexamic acid.
• Prevent the lethal triad: hypothermia, acidosis, coagulopathy (+ hypocalcaemia, hyperkalaemia).