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Maximum ABL calculation
 Definition
 EBV calculation: body wt (kg) x average blood volume (ml/kg)
 ABL= [EBV x (Hi-Hf)]/Hi
 Where:
 EBV=Estimated Blood Volume
 Hi= initial hemoglobin
 Hf= final hemoglobin
Average blood volumes
 Premature Neonates 95 mL/kg
 Full Term Neonates 85 mL/kg
 Infants 80 mL/kg
 Adult Men 75 mL/kg
 Adult Women 65 mL/kg
Normal Hct Values
 Men 42-52%
 Women 37-47%
 If the patient is obese, using the IBW or ABW will give more accuracy than an actual weight.
 Example
Question: Before surgery is to take place, what is the estimated blood volume (EBV)
of a female patient weighing 50 kg? Also, what is the allowable blood loss (ABL) of
this patient if her Hct is 45?
In the example above, EBV = 50kg x 65 (adult womans blood volume) = 3250 The
initial Hct (Hi) = 45%, her current Hct The final lowest acceptable Hct (Hf) = 30%
(What ever cut off is used clinically to decide how low the individuals Hct will be
allowed to drop. Thirty percent is used in this calculator but in reality this will vary
from case to case.) So the example would look like this:
 (3250 x (45  30))/45 = 1083 Using this rough estimate, the patient in this example
could loose 1083 mL of blood without needing a transfusion.
Replacing Blood Loss
Ideally, blood loss should be replaced with crystalloid or colloid solutions to
maintain intravascular volume (normovolemia) until the danger of anemia
outweighs the risks of transfusion.
 At that point, further blood loss is replaced with transfusions of red blood cells to
maintain hemoglobin concentration (or hematocrit) at that level.
 For most patients, that point corresponds to a hemoglobin between 7 and 10 g/dL
(or a hematocrit of 21-30%).
 Below a hemoglobin concentration of 7 g/dL, the resting cardiac output has to
increase greatly to maintain normal oxygen delivery
Estimating blood loss
 Dry sponges
44 hold ~ 10 mL blood
Ray-techs ~ 10-20 mL blood
Lap sponges ~ 50-100 mL blood
Pediatric cases should have sponges & gauze weighed for blood loss
Blood loss replacement
 Replace 1 mL blood with:
i. 3 mL crystalloid (i.e. NS, Dextrose, LR)
ii. 1 mL colloid (i.e. albumin**, Hespan速, Dextran速)
iii. 1 mL whole blood
iv. 1 mL PRBC
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  • 1. By
  • 2. Maximum ABL calculation Definition EBV calculation: body wt (kg) x average blood volume (ml/kg) ABL= [EBV x (Hi-Hf)]/Hi Where: EBV=Estimated Blood Volume Hi= initial hemoglobin Hf= final hemoglobin
  • 3. Average blood volumes Premature Neonates 95 mL/kg Full Term Neonates 85 mL/kg Infants 80 mL/kg Adult Men 75 mL/kg Adult Women 65 mL/kg Normal Hct Values Men 42-52% Women 37-47% If the patient is obese, using the IBW or ABW will give more accuracy than an actual weight.
  • 4. Example Question: Before surgery is to take place, what is the estimated blood volume (EBV) of a female patient weighing 50 kg? Also, what is the allowable blood loss (ABL) of this patient if her Hct is 45? In the example above, EBV = 50kg x 65 (adult womans blood volume) = 3250 The initial Hct (Hi) = 45%, her current Hct The final lowest acceptable Hct (Hf) = 30% (What ever cut off is used clinically to decide how low the individuals Hct will be allowed to drop. Thirty percent is used in this calculator but in reality this will vary from case to case.) So the example would look like this: (3250 x (45 30))/45 = 1083 Using this rough estimate, the patient in this example could loose 1083 mL of blood without needing a transfusion.
  • 5. Replacing Blood Loss Ideally, blood loss should be replaced with crystalloid or colloid solutions to maintain intravascular volume (normovolemia) until the danger of anemia outweighs the risks of transfusion. At that point, further blood loss is replaced with transfusions of red blood cells to maintain hemoglobin concentration (or hematocrit) at that level. For most patients, that point corresponds to a hemoglobin between 7 and 10 g/dL (or a hematocrit of 21-30%). Below a hemoglobin concentration of 7 g/dL, the resting cardiac output has to increase greatly to maintain normal oxygen delivery
  • 6. Estimating blood loss Dry sponges 44 hold ~ 10 mL blood Ray-techs ~ 10-20 mL blood Lap sponges ~ 50-100 mL blood
  • 7. Pediatric cases should have sponges & gauze weighed for blood loss Blood loss replacement Replace 1 mL blood with: i. 3 mL crystalloid (i.e. NS, Dextrose, LR) ii. 1 mL colloid (i.e. albumin**, Hespan速, Dextran速) iii. 1 mL whole blood iv. 1 mL PRBC