Anesthesia Department
Emergency Transfusion
Raafat Abdelazim
Intended Learning Outcomes
By the end of this lecture, the student will be able to:
1.
2.
3.
4.
5.
2
Understand why blood transfusion is indicated
Know how to estimate blood loss
Understand the compatibility testing
Assess the situation of “emergency”
Know how to manage “emergency transfusion”
3
Indications for Transfusion
When a patient is hemorrhaging:
• To  oxygen-carrying capacity
• To  intravascular volume
BT
Fluids (crystalloids or some colloids)
Normovolemic dilutional anemia:
If Hb < 6 g/dl inadequate splanchnic &
preportal O2 delivery & consumption
To restore
•IV volume
•Cardiac output
•Organ perfusion
Additional O2 delivery to organs &
tissues can only be enhanced by
RBCs via whole blood or PRBCs
Thus, increasing oxygen-carrying capacity is the only real indication for BT
4
Is O2-carrying capacity adequate?
Age
Cardiorespiratory function
Lab: Hb and Ht
Extreme variability from one patient to another
- Age/CR function/Lab
- An individual patient’s Hb level may vary markedly in the perioperative period
independent of and in addition to RBCs transfusions
Medical Organizations
Overall medical judgment rather than a
specific lab value
5
More complex
directions
These criteria cannot distinguish inadequate intravascular
volume from O2-carrying capacity
6
Using Hct and Hb:
Hct
<21
>30
Rarely require BT
Frequently require BT
(1988 National Institutes of Health Consensus Conference)
Hb
<6
>10
Almost always indicated
Rarely indicated
(2006 ASA Practice Guidelines)
7
To give BT according to Hct and Hb is a clinical judgment
based on many factors, such as:
1.
2.
3.
4.
5.
6.
7.
8.
8
Cardiovascular status
Age
Anticipated additional blood loss
Arterial oxygenation
Mixed venous PO2
Cardiac output
Blood volume.
O2 extraction ratio (invasive, results?)
ASA Practice Guidelines (2006)
1. BT is rarely indicated when Hb is > 10 g/dL and is
almost always indicated when it is < 6 g/dL, especially
when the anemia is acute.
2. The determination of whether intermediate Hb
concentrations (6 to 10 g/dL) justify or require RBC
transfusion should be based on the patient’s risk for
complications of inadequate oxygenation.
3. The use of a single Hb “trigger” for all patients and
other approaches that fail to consider all important
physiologic and surgical factors affecting oxygenation is
not recommended
9
4. When appropriate, the following may be beneficial:
• preoperative autologous blood donation
• intraoperative and postoperative blood recovery
• acute normovolemic hemodilution
• measures to blood loss (i.e., deliberate
hypotension and pharmacologic agents)
5. The indications for transfusion of autologous RBCs
may be more liberal than those for allogeneic RBCs
because of less frequent (but still significant) risks
associated with the former.
10
Miller’s Anesthesia (2005 & 2010)
The following indications were recommended with the rule
of thumb that administration of 1 unit of packed RBCs
will  Hct value by 3%-5%:
1. Blood loss > 20% of blood volume when > 100 mL
2. Hb level < 8 g/dL
3. Hb level < 10 g/dL with major disease (e.g., emphysema,
IHD)
4. Hb level < 10 g/dL with autologous blood
5. Hb level < 12 g/dL and ventilator dependent
11
Both recommendation lists agree that a
transfusion trigger of 8.0 g/dL or less can be
tolerated by patients who:
are not critically ill
do not have severe cardiorespiratory disease
12
Average Blood Volumes
13
Age
Blood volume
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
Allowable Blood Loss
ABL = EBV [Hct (i) - Hct (f)] / Hct (i)
EBV= Estimated Blood Volume
Hct (i)= initial Hct
Hct (f)= final lowest acceptable Hct
e.g, BW= 70kg  EBV= 75x70= 5250 ml
Hct(i)= 44, Hct(f)= 30
ABL= 5250 [44-30] / 44= 1670 ml
14
Allowable Blood Loss Corrected for Dilution
EBL = EBV [Hct (i) - Hct (f)] / Hct (m)
EBV= Estimated Blood Volume
Hct (i)= initial Hct
Hct (f)= final Hct
Hct (m)= mean (of i & f)
e.g, BW= 70kg  EBV= 75x70= 5250 ml
Hct(i)= 44, Hct(f)= 30, Hct(m)= 37
EBL= 5250 [44-30] / 37= 1980 ml
15
Compatibility Testing
• ABO-Rh Typing
• Antibody Screening
• Crossmatching
These tests were designed to demonstrate harmful antigen-antibody
interactions in-vitro so that harmful in-vivo antigen-antibody interactions
could be prevented
16
17
ABO-Rh Typing
Accidental transfusion of ABO-incompatible blood  the most serious and
tragic reactions.
These reactions result from naturally occurring antibodies which are
formed whenever the individual lacks either or both of the A and B antigens
Anti-A
Anti-B
+
Complement
IV Hemolysis
Antibodies are directed against those antigens that are lacking in the
individual’s own cells
ABO typing is performed by testing RBCs for the A and B antigens and the
serum for the A and B antibodies before transfusion
18
A
B
A
B
B
B
O
O
O
O
A
B
A
B
A
B
A
B
A
B
B
A
O
B
A
A
B
A
A
B
19
B
B
B
A
B
O
A
A
A
B
A
A
Rh
15
Rh+ve
Rh-ve
85
D antigen
No D antigen
85%
Rh(D) positive
15%
Rh(D) negative
60-70% of Rh(D)-negative recipients are immunized
(produce anti-D) if they are given BT with Rh(D)-positive blood
20
Donor Blood Groups that Patients Can Receive
21
Donor
Recipient
O
O, A, B, AB
A
A, AB
B
B, AB
AB
AB
Antibody Screening
• It is carried out in 3 phases.
• It is completed in 45-60 min
• It is a trial transfusion between the recipient’s serum
and commercially supplied RBCs.
• RBCs are specifically selected to contain optimal
numbers of RBC antigens or those antigens that will
react with antibodies that are commonly implicated in
hemolytic transfusion reactions.
22
Antibody Screening (Contd.)
• The screen for unexpected antibodies is also used on
donor serum and is performed shortly after withdrawal
of blood from the donor.
• It is necessary to screen donor serum for unexpected
antibodies to prevent their introduction into the recipient
serum.
• This screen is performed primarily to prevent reactions
between transfused donor units.
23
Crossmatching
• A trial transfusion within a test tube
• Donor RBCs are mixed with recipient serum to
detect a potential for serious transfusion reaction
• Can be completed in 45 to 60 minutes
• Three phases:
1. Immediate phase
2. Incubation phase
3. Antiglobulin phase
24
1. Immediate phase
• It is conducted at room temperature
• A check against errors in ABO typing
• It detects:
– ABO incompatibilities and
– those caused by naturally occurring antibodies in the
MN, P, and Lewis systems
• It takes 1 to 5 minutes to complete
25
2.Incubation phase
• It involves incubation of the 1st-phase reactions at 37°C
in:
a) albumin or
b) low-ionic strength salt solution.
• The addition of (a) and (b) aids in the detection of:
–
–
incomplete antibodies or
those antibodies that are able to attach to a specific antigen
(i.e., sensitization) but are unable to cause agglutination in a
saline suspension of RBCs.
• It detects antibodies in the Rh system
• Incomplete antibodies missed in this phase can be
detected in the subsequent antiglobulin phase
26
3.Antiglobulin phase
• It involves the addition of antiglobulin sera to the
incubated test tubes
• With this addition, antihuman antibodies present in the
sera become attached to the antibody globulin on the
RBCs, causing agglutination
• It detects most incomplete antibodies in the blood group
systems, including the Rh, Kell, Kidd, and Duffy blood
group systems
27
Blood
28
ABO-Rh
Type
Screening for
antibodies
Recipient
+
Unexpected antibodies
Donor – All
+
Unexpected antibodies
Donor – Emergency
+
Anti-A & Anti-B
Crossmatching
+
x
Approaches Requiring Less Than
a Complete Crossmatch
29
• Type and Screen
• Maximal Surgical Blood Order Schedule
• Is the Crossmatch Really Needed?
30
Type and Screen
The patient’s serum is screened for the presence of
unexpected antibodies by incubating it with
selected reagent RBCs (i.e., screen cells).
These cells contain all antigens capable of inducing
clinically significant RBC antibody reactions
1
2
For those few patients in whom the antibody screen reveals the
presence of unexpected antibody, the antibody is subsequently
identified in the blood bank and units of blood lacking the
corresponding antigen are set aside for surgery.
31
If an emergency transfusion is
required after type and screen alone
An immediate-phase crossmatch is
performed before transfusion
to eliminate reactions that may result from
human errors in ABO-Rh typing
Blood given in this manner is > 99% effective in
preventing incompatible transfusion reactions due
to unexpected antibodies
32
Remember . . .
• Complete transfusion testing for compatibility between
donor and recipient blood ensures optimal safety and
therapeutic effect of transfused blood
• The type and screen without the complete crossmatch
does not protect against reactions due to antibodies
reactive against lower-incidence antigens, those not
represented on the screening cells but present on the
donor RBCs
• Generally, antibodies that are not detected in the type
and screen are weakly reactive antibodies that do not
result in serious hemolytic transfusion reactions
33
Type and Hold
• This refers to a sample of blood from a
potential blood recipient received by the
blood bank in which the blood type (but
no crossmatch) has been ordered.
• Because of the confusion that has arisen
with type and screen, the type and hold
terminology and method of ordering blood
have been abandoned by most blood
banks.
34
Maximal Surgical Blood Order Schedule
• Routine preoperative crossmatching of blood for surgical
cases means that:
– crossmatched blood is unavailable for others for 24 to 48 hours.
– 1 to 2 days is lost and the chance for outdating .
• For certain elective surgical procedures, the number of
crossmatched units that are ordered frequently far
exceeds the number actually transfused  to quantify
this problem better, the crossmatch-to-transfusion
(C/T) ratio has been used
35
C/T ratio
• If the C/T ratio is high, the blood bank is burdened with:
– keeping a large blood inventory
– using excessive personnel time
– having a high incidence of outdated units
• For surgical procedures in which the average number of
units transfused per case is < 0.5 
Type and screen
Positive
The blood bank must provide
compatible units that lack the
corresponding antigen
36
Negative
No crossmatching
• Blood banks attempt to maintain C/T ratios of
2.1 to 2.7.
• To  the rate of use and  the C/T ratio, blood
banks attempt to  the emphasis on
crossmatching of blood through:
– such means as the type and screen and
– such programs as the maximal surgical blood order
schedule
• This schedule consists of a list of surgical
procedures and the maximal number of units of
blood that the blood bank will crossmatch for
each procedure
37
• This schedule is based on the BT experience for
surgical cases in hospitals in which the schedule
is employed.
• Each hospital’s maximal surgical blood order
schedule is developed by the suppliers and the
users of blood in that hospital, such as:
– blood bankers
– anesthesiologists
– surgeons
38
Is the Crossmatch Really Needed?
39
In 100
previously transfused patients
pregnant patients
Only ONE may have
an irregular antibody
other than
Anti-A
Anti-B
40
Anti-Rh(D)
Kell
C
E
Kidd
The 1%
Irregular antibodies
Some
Reactive only at
temperatures < 30°C
Insignificant in
most transfusions
Some
Reactive at about
30°C
Serious reactions IF the
transfused cells contain
appropriate antigen
The most common of clinically significant antibodies,
in order of probable significance:
Anti-Rh(D) > Kell > C > E > Kidd
41
If the correct ABO and Rh blood
type is given, the possibility of
transfusing incompatible blood is
<1 chance in 1000
42
Antibody screening
The chance of missing an antibody that is
potentially dangerous is
< 1 in 10,000
43
Safety (chance of compatible transfusion)
100.00%
99.94%
99.95%
99.95%
99.90%
99.85%
99.80%
99.80%
99.75%
99.70%
ABO-Rh typing
44
ABO-Rh typing +
antibody screen
Crossmatch
Emergency Transfusion
45
For those situations that do not allow time for
complete testing, an abbreviated format for testing
can be used.
The preferred order for the selection of blood is as
follows:
Type-Specific, Partially
Crossmatched Blood
Type-Specific,
Uncrossmatched Blood
Type O Rh-ve,
Uncrossmatched Blood
46
Type-Specific, Partially Crossmatched Blood
ABO-Rh typing
Immediate-phase crossmatch
Room temp.
In 1 to 5 minutes
Centrifugation
Donor’s RBCs
Pt’s serum
47
Reading for macroscopic agglutination
ABO
Unexpected antibodies:
MN
P
Lewis
Type-Specific, Uncrossmatched Blood
• Almost successful for those who have
never been exposed to foreign RBCs
• Caution should be used for patients:
– who have previously received transfusions or
– have had pregnancies
48
Type O Rh-ve (Universal Donor),
Uncrossmatched Blood
• It lacks the A and B antigens  cannot be
hemolyzed by anti-A or anti-B antibodies in the
recipient’s blood
• Some type O donors produce high titers of
hemolytic IgG, IgM, anti-A, and anti-B
antibodies  destruction of A or B RBCs of a
non–type O recipient
• RBCs vs whole blood:
49
Preferrably
Type O Rh-ve,
uncrossmatched PRBCs
Have smaller volumes of plasma
and are almost free of hemolytic
anti-A and anti-B antibodies
Type O Rh-ve
whole blood
If to be used, the blood bank
must supply it free of hemolytic
anti-A and anti-B antibodies
50
During emergency transfusion of > 2 units of type O Rh-ve,
uncrossmatched whole blood, the patient probably cannot be switched
to his blood type (A, B, or AB) as soon as the blood bank determines
the correct blood type
Switching could cause major
intravascular hemolysis of
donor RBCs by increasing
titers of transfused anti-A
and anti-B
Continued use of O Rh-ve whole
blood results only in minor
hemolysis of recipient RBCs, with
hyperbilirubinemia as the only
complication
The patient must not be transfused with his correct blood type until the
blood bank determines that the transfused anti-A and anti-B has
decreased to levels that permit safe transfusion of type-specific blood
51
Specific Recommended Protocol
For patients who are hypovolemic and require blood transfusion:
1. Infuse crystalloids or colloids.
2. Draw a blood sample for typing and
crossmatching
3. If crossmatched blood is not ready to give, use:
–
–
–
–
–
52
type-specific or
Type-Specific
type O Rh-negative cells or
O-ve cells
type O Rh-positive cells for males or
postmenopausal females without a history of O+ve cells?
transfusions;
Type-Specific, partially XM
type-specific, partially crossmatched blood;
or type-specific, crossmatched blood. Type-Specific, XM