This document discusses various methods for estimating blood loss and determining when blood transfusions are needed. It notes that visual inspection and clinical estimates typically underreport blood loss by 30-40%. Other estimation methods include changes in vital signs, urine output, weighing blood-soaked materials, and using the hemodilution or percentage method to calculate allowable blood loss based on patient condition and initial hematocrit. Training programs are recommended to help clinicians more accurately estimate blood loss amounts.

1. -BLOOD ESTIMATION
-Dr Nisar Ahmed Arain
Assistant Professor
Anesthesia/Critical Care/ER

2. VISUAL INSPECTION
-It is Inaccurate. In some reports, the amount of blood
estimated to have been lost by inspection was half
the measured loss
CLINICIANS
-They typically under estimate Post-Partum blood loss
by 30% to 40%
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

3. ON AVERAGE
-Women lose about
a- 500 ml in a
b-1000 ml in CS
C-1500 ml in a cesarean Hysterectomy.
THE CRITICAL AREA
-Where you want to estimate blood loss is
over 2,000 ml, and we almost always
underestimate that. By that point, the
patient has Hypotension, and has significant
tachycardia, and is in SHOCK

4. -Clinical Methods of Estimation

5. -Blood Pressure and Heart Rate
--By the time you detect changes in Blood pressure OR Heart
rate suggesting PPH, the women already has lost 1/3rd of
her blood volume
--Orthostatic Hypotension would tell you that patient has lost
20% to 25% of her blood, but if she is sitting or lying down
on the delivery table, you are unlikely to detect that
symptom.
--Hypotension reflects a loss of 30% to 35% of blood volume.
“Do not wait for Hypotension to develop along with its
signs and symptoms” and to treat for PPH “Do not wait
to start seeing S and S.
-1-Blood Pressure and Heart Rate

6. -Hematocrit
--It needs 4 hours for significant changes and 48 hours for
complete compensation
--In acute hemorrhage, the immediate Hematocrit may not
reflect acute blood loss
--After the loss 1000 ml of blood, the hematocrit typically
falls only 3 volume percent in the first hour
--When resuscitation is given with rapid infusion of I/V
crystalloids, there is a rapid equilibrium in the circulation.
--During an episode of acute significant hemorrhage, the initial
hematocrit is always in the highest limits. This is true
weather it is measured in the delivery room or operation
room, or recovery room.
-2--Hematocrit

7. --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 tern,
perfusion of other vital organs, because renal blood flow
is especially sensitive to the changes in the blood volume.
--Urine flow of atleast 30 ml and preferably 60 ml per hour
should be maintained
--With potentially serious hemorrhage, an indwelling catheter
should be inserted to measure urine flow.
-3-Urine output

8. --4-Weighing Packs:- and correlate with
blood loss: Hospitals keeps scales in
the Delivery rooms to weigh Lap
sponges and other materials to
estimate blood loss 1 kg soaked
swabs = 1000 ml
-5-perhaps the easiest method of
estimating is to picture a soda can
which would hold about 350 ml of
blood. When you look at blood clots
or blood in a canister, estimate how
many cans of soda are represented
and you will be close to blood volume
lost. The principal is to recognize
volume

9. 6- Maximum Capacity of Swabs
a-Small =(10 X 10 cm) 60 ml
b-Medium =(30 X30 cm) 140 ml
c-Large =(45 X 45 cm) 350 ml
7-Floor Spill
a-50 cm Diameter = 500 ml
b-75 cm Diameter = 1000 ml
c-100 cm Diameter = 1500 ml
8-Vaginal PPH
Limited to bed only:- Unlikely to exceed 1000 ml
Spilling from bed to Floor likely to exceed 1000 ml

10. -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 cells
transfusion
--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 under
estimated.
--Clinical estimation of blood loss suffer from large
interobserver variability and poor repeatability.

11. --The extent of blood loss and response to
transfusion is reflected in the changes
in the Hematocrit
--This change may be used to calculate the
actual blood loss using suitable
formulae
-Actual Blood Loss cont.

12. -Actual Blood Loss
--It is a modification of the gross formula
ABL = BV [Hct (i) – Hct (f) / Hct (m)
BLOOD VOLUME = Body weight in Kgms X 70 ml Kg – 1
Hct (i), Hct (f) and Hct (m): the initial, final and mean
(of the initial and final) Hematocrits respectively
BLOOD VOLUME
a-NEONATES = 85 to 90 ml / Kg body weight
b-CHILDREN = 80 ML / Kg body weight
c-ADULTS = 70 ml / Kg body weight

13. -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
(1 ml of blood weighs approximately 1 gm)
--3-Substract 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

14. -The Decision to transfuse Blood
-Percentage Method
-Calculate the patients 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 Normovolemia is maintained

15. Patient condition Health Average Poor
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%

16. -HEMODILUTION METHOD
--Decide on the lowest acceptable Hb or Hematocrit (Hct) that
may be safely tolerated by the patient
--Calculate the allowable volume of blood loss that can occur
before a blood transfusion becomes necessary.
--Replace the blood loss up to the allowable volume with
Crystalloid or colloid fluids to maintain Normovolemia.
--If the allowable blood loss volume is exceeded, further
replacement should be with blood

17. --Which ever method is used, the decision to transfuse
will depend on the clinical condition of the patient
and supply. This particularly limited in patients with
evidence of severe cardiac or respiratory disease or
pre-existing anemia
--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 maximize the
benefits of the transfusion

18. --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
Re-Evaluating the Hematocrit in between
resulted in 90% of the un-necessary
transfusions
--Determination of the Hematocrit
immediately before administration of each
unit would reduce blood consumption by 25%.

19. -STRONG RECOMENDATIONS
-A PROGRAM TO TRAIN DOCTERS AND
NURSES TO ESTIMATE BLOOD LOSS
PERFACTLY IS RECOMENDED

20. THANK YOU