assessment of blood loss

Assessment of blood loss Prof. Aboubakr elnashar

Benha university hospital, Egypt Email: [email protected]

Aboubakr Elnashar

•Visual inspection is inaccurate. In some reports, the

amount of blood estimated to have been lost by

inspection was half the measured loss.

•Clinicians typically underestimate postpartum blood loss

by 30%-50%

•Importantly, in obstetrics, part or all of the hemorrhage

may be concealed.

•Clinicians commonly record blood loss using

inaccurately low numbers. "How can we teach people to

accurately and honestly record blood loss?“

Aboubakr Elnashar

•On average, women lose about

500 cc in a vaginal delivery,

1,000 cc in CS, and

1,500 cc in a cesarean hysterectomy.

•The critical area where you want to estimate blood loss

is over 2,000 cc, and we almost always underestimate

that. By that point, the patient has hypotension, has

significant tachycardia, and is in shock.

Aboubakr Elnashar

A. Clinical methods

Aboubakr Elnashar

1. BP, HR:

•By the time you detect changes in BP or HR suggesting

PPH, the woman already has lost 1/3 of her blood

volume

•Orthostatic hypotension would tell you that the patient

has lost 20%-25% of her blood, but if she is sitting or

lying down on the delivery table, you're unlikely to detect

that symptom.

•Hypotension reflects a loss of 30%-35% of blood

volume. "Do not wait for hypotension" to treat for PPH

"Do not wait to start seeing S and S.

Aboubakr Elnashar

2. Hematocrit:

•It needs 4 h for significant changes and 48 h for

complete compensation

•In acute hemorrhage, the immediate hct may not reflect

actual blood loss.

•After the loss of 1000 mL, the hct typically falls only 3

volume % in the first hour.

•When resuscitation is given with rapid infusion of IV

crystalloids, there is rapid equilibration.

•During an episode of acute significant hemorrhage, the

initial hct is always the highest. This is true whether it is

measured in the delivery room, operating room, or

recovery room.

Aboubakr Elnashar

3. Urine output

•One of the most important "vital signs" to follow in the

bleeding patient with obstetrical hemorrhage.

•In the absence of diuretics, the rate of urine formation

reflects the adequacy of renal perfusion and, in turn,

perfusion of other vital organs, because renal blood flow

is especially sensitive to changes in blood volume.

•Urine flow of at least 30 mL and preferably 60 mL/h

should be maintained.

•With potentially serious hemorrhage, an indwelling

catheter should be inserted to measure urine flow.

Aboubakr Elnashar

4. Weighing packs and correlate with blood loss:

Hospital keeps scales in delivery rooms to weigh lap

sponges & other materials to estimate blood loss.

1kg soaked swabs: 1000ml

5. Perhaps the easiest method of estimating is to picture

a soda can, which would hold about 350 cc of blood.

When you look at blood clots or blood in a canister,

estimate how many cans of soda are represented, and

you'll be close to blood volume lost. "The principle is to

recognize volume.

Aboubakr Elnashar

6. Maximum capacity of Swab

Small (10x10cm): 60ml

Medium (30x30 cm): 140ml

Large (45x45 cm): 350ml

7. Floor spill

50 cm diameter: 500ml



8. Vaginal PPH

limited to bed only Unlikely to exceed 1000ml

spilling from bed to floor likely to Exceed 1000ml

Aboubakr Elnashar

B. Actual blood loss

•In the perioperative period clinical estimation of blood

loss is inaccurate and alone should not be used to

determine the need for red blood cell transfusions.

•Poor agreement between the Actual Blood Loss and the

estimated blood loss. The 95% confidence intervals (-

719.939 ml to+1265.619 ml) suggest that clinical

estimation alone may result in unacceptable under or

over transfusions.

•In 64% of the cases the blood loss was underestimated.

•Clinical estimations of blood loss suffer from large

interobserver variability and poor repeatability.

Aboubakr Elnashar

•The extent of blood loss and response to transfusion is

reflected in the changes in the hct.

•This change may be used to calculate the Actual Blood

Loss using suitable formulae.

Aboubakr Elnashar

The Actual Blood Loss is a modification of the Gross

formula:

ABL = BV [Hct (i) - Hct (f)]/ Hct (m)

Blood Volume=Body Wt in Kgs x 70 mlkg-1

Hct (i), Hct (f) and Hct (m): the initial, final and mean (of

the initial and final) Hematocrits respectively.

Blood volume

Neonates: 85-90ml/ kg body weight

Children: 80ml/ kg body weight

Adults: 70ml/ kg body weight

Aboubakr Elnashar

Calculating blood loss in theatre:

1. Weigh a dry swab.

2. Weigh blood soaked swabs as soon as they are

discarded and subtract their dry weight (1ml of blood

weighs approximately 1gm).

3. Subtract the weight of empty suction bottles from the

filled ones.

4. Estimate blood loss into surgical drapes, together with

the pooled blood beneath the patient and onto the

floor.

5. Note the volume of irrigation fluids, subtract this

volume from the measured blood loss to estimate the

final blood loss.

Aboubakr Elnashar

The decision to transfuse blood:

1. Percentage method.

Calculate the patient’s blood volume.

Decide on the percentage of blood volume that could be

lost but safely tolerated, depending on the clinical

condition of the patient, provided that normovolaemia

is maintained (table)

Aboubakr Elnashar

Patient condition Health Average Poor

Percentage

method

Acceptable loss of

blood volume

before transfusion

method

30% 20% <10%

Haemodilution Hb 7-8g/dl

Hct 21-24%

8- 9g/dl

24-27%

10g/dl

30%

Aboubakr Elnashar

2. Haemodilution method. Decide on the lowest acceptable Hb or Haematocrit (Hct) that may

be safely tolerated by the patient (table ).

Calculate the allowable volume of blood loss that can

occur before a blood transfusion becomes necessary.

Replace blood loss up to the allowable volume with

crystalloid or colloid fluids to maintain

normovolaemia.

If the allowable blood loss volume is exceeded, further

replacement should be with blood.

Aboubakr Elnashar

•Whichever method is used, the decision to transfuse

will depend on the clinical condition of the patient and

their ability to compensate for a reduction in oxygen

supply. This is particularly limited in patients with

evidence of severe cardiac or respiratory disease or pre-

existing anaemia.

•The methods described are simple guidelines which

must be altered according to the clinical situation.

•Further blood loss should be anticipated, particularly

postoperatively.

•Whenever possible, transfuse blood when surgical

bleeding is controlled. This will maximise the benefits of

the transfusion.

Aboubakr Elnashar

•The American College of Physicians recommended that

RBC transfusions should be done unit by unit and the

patient should be evaluated between each transfusion.

•Excessive intraoperative transfusion and the practice of

administering blood without reevaluating the hct in

between resulted in 90% of the unnecessary

transfusions.

•Determination of the hct immediately before

administration of each unit would reduce blood

consumption by 25%.

Aboubakr Elnashar

Recommendation

A program to train doctors & nurses to estimate blood loss.

Aboubakr Elnashar

Thanks

Aboubakr Elnashar