Physiological triggers for blood transfusion in the icu

in ICU setting/some case to guide you

1. Physiological triggers for blood Physiological triggers for blood
Transfusion in the ICUTransfusion in the ICU
Dr. T.R. ChandrashekarDr. T.R. Chandrashekar
IntensivistIntensivist
K.R.HospitalK.R.Hospital
BangaloreBangalore

2. Some facts about Blood transfusionSome facts about Blood transfusion
Only absolute indication is to increase oxygen
delivery to Tissues in anaemic patients- ie to
increase oxygen carrying capacity.
It is a tissue transplantation procedure
Blood should not be used for intravascular
volume expansion

3. Transfusion Trigger
Acceptable hemoglobin concentration
Risk of blood transfusion Risk of low hemoglobin

4. Oxygen transport physiology Oxygen transport physiology

5. Oxygen transport physiologyOxygen transport physiology
Oxygen to mitochondria is the goalOxygen to mitochondria is the goal
We accept low Hb in critically ill patients We accept low Hb in critically ill patients
because increasing the Hb with old stored blood because increasing the Hb with old stored blood
increases mortality.increases mortality.
Because of low Hb –the oxygen content is lowBecause of low Hb –the oxygen content is low
Hence we should we should be certain all along Hence we should we should be certain all along
the oxygen cascade-Lung to mitochondria, the the oxygen cascade-Lung to mitochondria, the
system is able to increase the delivery/extract system is able to increase the delivery/extract
oxygenoxygen

6. OxygenOxygen
deliverydelivery
CaO2 = (1.34 x Hb x SaO2) +dissolved O2
DO2 = CO X CaO2
Cardiac output= HR x SV
Mitochondria in end organs

7. Oxygen extraction/ reserveOxygen extraction/ reserve
Sao2 95-98%/Co=5L/mtSao2 95-98%/Co=5L/mt
At Hb of 15 g % Oxygen content is 1000 mlAt Hb of 15 g % Oxygen content is 1000 ml
At Hb of 10 g % Oxygen content is 698 mlAt Hb of 10 g % Oxygen content is 698 ml
At Hb of 7 g % Oxygen content is 445 mlAt Hb of 7 g % Oxygen content is 445 ml
At this Hb we have reduced the reserveAt this Hb we have reduced the reserve

8. Do2/Vo2Do2/Vo2
CO/Oxygen saturation remain constantCO/Oxygen saturation remain constant
Hb 7 g%Hb 7 g%
225ml normal O2 utilisation
Reserve
Cannot be utilised
225ml normal O2 utilisation/ No reserve
Hb 15g%

9. DO2/VO2DO2/VO2
Patients have to be kept them well above the Critical Point so
that oxygenation of any tissue is not compromised
Supply
dependent
area
In critically ill
supply dependent
area

10. Factors that may result in a patient being
potentially closer to the critical point
than normal
Reduced oxygen delivery.
(a) Decreased cardiac output:
(i) Pre-morbid disease e.g.,IHD, valvular heart disease.
(ii) Hypovolaemia e.g., increased capillary leak.
(iii) Arrhythmias e.g., atrial fibrillation.
(iv) Pulmonary embolism.
(v) Specific heart muscle disease e.g., systemic inflammatory
response syndrome (SIRS) related cardiomyopathy.
(b) Hypoxaemia secondary to acute
respiratory failure.-(ALI)/ (ARDS).

11. Factors that may result in a patient
being potentially closer to the critical
point than normal
Pain, stress, anxiety.
Shivering.
Fever.
Severe infection.
Sepsis/(SIRS).
Trauma
Surgery.
Burns.
Adrenergic drug
infusions.
Work of breathing e.g.,
during weaning.
Convulsions.
Increased oxygen consumption

12. Does old blood improve oxygen Does old blood improve oxygen
content?content?

13. Storage Defects and Microvascular
Perfusion
Decreased 2,3- DPG,
ADP,NO
Build-up of cytokines,
Free Hb, K+, debris
Poor deformability
Will they improve oxygen
content and delivery ?
Immune suppression
Infections
Clinical and animal studies report contradictory findings about the oxygenation capacity of
stored RBCs

14. Transfusion “Trigger” Controversy
Transfusion trigger:
“a particular
hemoglobin level of
discomfort in the
Prescribing physician,
Not defined by clear
Physiologic
parameters”
8/24?
7/21?
10/30?
Transfusion paradigms

15. Sources of Variation in Transfusion Practice
Physician practice variation
Physicians make highly individualized trade-off
decisions between the risks of anemia vs. the risks
and benefits of transfusion
Several studies show this individualization is more
aligned with the physician’s bias rather than
physiologic status of the patient
This decision is often based more upon custom
and habit rather than formal training and current
evidence based principles

16. Transfusion triggerTransfusion trigger
(Crit Care Med 2009; 37:3124 –3157)

17. Recommendations Regarding Indications for
RBC Transfusion in the General Critically Ill
Patient
RBC transfusion is indicated for patients with
evidence of hemorrhagic shock. (Level 1)
RBC transfusion may be indicated for patients
with evidence of acute hemorrhage and
hemodynamic instability or inadequate oxygen
delivery. (Level 1)

18. Indications for RBC Transfusion in the
General Critically Ill Patient
A “restrictive” strategy of RBC transfusion (transfuse
when Hb <7 g/dL) is as effective as a “liberal”
transfusion strategy (transfusion when Hb < 10 g/dL)
in critically ill patients with hemodynamically stable
anemia, except possibly in patients with acute
myocardial ischemia. (Level 1)
In critically ill pts on the ventilator, the above also holds
true. LEVEL II
In resuscitated, critically ill trauma pts, the above holds
true. LEVEL II
In critically ill patients with stable cardiac disease, the
above holds true. LEVEL II. (very important:
prevention of ischemia not supported by literature)

19. Anemia in the ICUAnemia in the ICU
95% of ICU patients have anemia by Day 395% of ICU patients have anemia by Day 3
The anemia typically persists throughout the ICU and The anemia typically persists throughout the ICU and
hospital stayhospital stay
~50% patients admitted to ICU’s in USA receive ~50% patients admitted to ICU’s in USA receive
transfusionstransfusions
~85% patients who stay in ICU > 1 week receive ~85% patients who stay in ICU > 1 week receive
transfusionstransfusions
On average, 9.5 units of PRBC per patientOn average, 9.5 units of PRBC per patient
40% during the first week40% during the first week
60% ongoing “need” for transfusion @ 2-3 units/week60% ongoing “need” for transfusion @ 2-3 units/week
Acute blood loss accounts for only 35% of transfusion Acute blood loss accounts for only 35% of transfusion
eventsevents
Why does patients become Anaemic in ICU?

20. Causes of Anemia in the Critically IllCauses of Anemia in the Critically Ill
Diagnostic phlebotomy (~ 750-900 mL/ICU stay)Diagnostic phlebotomy (~ 750-900 mL/ICU stay)
Average 40-60 mL/day/Accounts for 20% of total blood lossAverage 40-60 mL/day/Accounts for 20% of total blood loss
Occult and overt bleeding: wounds, drains & GI tractOccult and overt bleeding: wounds, drains & GI tract
Anemia due to underproductionAnemia due to underproduction
Blunted erythropoietin response to low HctBlunted erythropoietin response to low Hct
Cytokines (IL-1Cytokines (IL-1bb, TNF-, TNF-aa) inhibit erythropoietin gene) inhibit erythropoietin gene
Inflammatory processes in the ICUInflammatory processes in the ICU
Altered iron metabolismAltered iron metabolism
Impaired proliferation and differentiation of erythroid Impaired proliferation and differentiation of erythroid
progenitorsprogenitors
Hematologically similar to anemia of chronic disease (low iron, Hematologically similar to anemia of chronic disease (low iron,
low TIBC, normal/high ferritin)low TIBC, normal/high ferritin)

21. Physiological triggerPhysiological trigger
The use of a single hemoglobin “trigger” for all
patients is not recommended
Decision for RBC transfusion should be based
on an individual patient’s intravascular volume
status, evidence of shock, duration and extent of
anemia, and cardiopulmonary physiologic
parameters. (Level 2)

22. Physiological triggerPhysiological trigger
It is obvious that for any individual the clinician
cannot know where the Critical Point lies nor
know how close to the Critical Point a patient
can go.
What the clinician does know are the factors
involved and the overt pathophysiology in an
individual patient which are likely to influence
their proximity to the Critical Point.

23. The physiologic effect of anemia
Is clinically assessed by examination of
indicators of
 Global and organ-specific oxygen delivery.

24. How well is anemia tolerated?How well is anemia tolerated?
Are the compensatory mechanisms Are the compensatory mechanisms
working?working?
Is their a Tissue oxygen deficit?Is their a Tissue oxygen deficit?
SymptomsSymptoms
Rate Pressure product-Heart compensationRate Pressure product-Heart compensation
Global oxygenation parametersGlobal oxygenation parameters
Scvo2/lactateScvo2/lactate
Tissue oxygenation parametersTissue oxygenation parameters
Gastric tonometryGastric tonometry
P300 latencyP300 latency
S-T segment analysisS-T segment analysis

25. Anemia symptomsAnemia symptoms
Exertional dyspnea
 Chest pain
 Lethargy
 Pallor
 Hypotension
 Tachycardia
 Impaired consciousness

26. Points to consider before Blood Points to consider before Blood
transfusiontransfusion
Hemodynamic status,
Rate of ongoing blood loss
Likelihood of further blood loss
Evidence of end-organ compromise
Risk of CAD
Balance of risks vs. benefits of transfusion
These findings will determine the urgency of response
and will determine whether or not transfusion is
indicated

27. Three possible scenarios in ICUThree possible scenarios in ICU
Acute bleedAcute bleed
Septic shock during resuscitationSeptic shock during resuscitation
Hemodynamicaly stable euvolemic anemia in Hemodynamicaly stable euvolemic anemia in
critically ill patient critically ill patient

28. Acute bleed Acute bleed
Patient with esophageal
varices and portal
hypertension- with
bleeding (1L)
Baseline Hb 8g%Baseline Hb 8g%
Blood transfusion before
the hematocrit drops and
prior to endoscopic
intervention

29. Septic shock-EGDTSeptic shock-EGDT

30. Hemodynamically stable critically ill Hemodynamically stable critically ill
patientpatient
IssuesIssues
Hemodilution Hemodilution

31. CaO2 = (1.34 x Hb x SaO2) +dissolved O2
DO2 = CO X CaO2
Cardiac output
Mitochondria in end organs
7 g %
ALI/ARDS
PE
Sepsis induced
myocardial depression
Drugs
Inotropes
Pericardial effusion
vv
MMDS-cannot extract O2
O
2
lactate
CO
2
vv
aa

32. Case scenario…Case scenario…
20 year old male patient with APD-accidental 20 year old male patient with APD-accidental
phenol ingestion vitals stable Hb 8.6 g% had a phenol ingestion vitals stable Hb 8.6 g% had a
bout of coffee ground aspirationbout of coffee ground aspiration
Endoscopy done -bleeder clippedEndoscopy done -bleeder clipped
Vitals stableVitals stable
Hb 6.9 g %Hb 6.9 g %
Do we transfuse ?Do we transfuse ?

33. Case scenario…Case scenario…
45 year old 70 kg diabetic admitted with H1N1 45 year old 70 kg diabetic admitted with H1N1
ARDS, Day 6ARDS, Day 6
On ventilator PEEP14 cms H2o/ FIO2 70%On ventilator PEEP14 cms H2o/ FIO2 70%
Vt 300ml, plateau pressure 30 cms H2oVt 300ml, plateau pressure 30 cms H2o
Pco2 75/Po2 53/Sao2 86%Pco2 75/Po2 53/Sao2 86%
Vitals stable, febrile, Scvo2 58%Vitals stable, febrile, Scvo2 58%
Hb 7.3 g %Hb 7.3 g %
Do we transfuse ?Do we transfuse ?

34. Case scenario…Case scenario…
65 year old septic patient with Scvo2 of 55%65 year old septic patient with Scvo2 of 55%
With IHD -Ef 45% on two inotropes BP With IHD -Ef 45% on two inotropes BP
110/54 admission Hb 8.2 g%, Hr 120/mt, mild 110/54 admission Hb 8.2 g%, Hr 120/mt, mild
ST elevation in chest leads consistent with old ST elevation in chest leads consistent with old
ECG findingsECG findings
Do we transfuse?Do we transfuse?
YESYES

35. Case scenario…Case scenario…
45 year old DM with Fournier's Gangrene has 45 year old DM with Fournier's Gangrene has
BP of 102/49 on dobutamine, noradrenaline BP of 102/49 on dobutamine, noradrenaline
high doses, on ventilator Pao2-125 high doses, on ventilator Pao2-125
HR 134/mt SCvo2 49% CO-7L/mtHR 134/mt SCvo2 49% CO-7L/mt
Hb is 10.2 g %Hb is 10.2 g %
What do we do?What do we do?
MMDSMMDS

36. Recommendations Regarding Strategies Recommendations Regarding Strategies
to Reduce RBC Transfusionto Reduce RBC Transfusion
The use of low-volume adult or pediatric blood The use of low-volume adult or pediatric blood
sampling tubes sampling tubes
The use of blood conservation devices for The use of blood conservation devices for
reinfusion of waste blood with diagnostic sampling reinfusion of waste blood with diagnostic sampling
Intraoperative and postoperative blood salvage Intraoperative and postoperative blood salvage
Alternative methods for decreasing transfusion may Alternative methods for decreasing transfusion may
lead to a significant reduction in allogeneic blood lead to a significant reduction in allogeneic blood
usage. usage.

37. Conclusion Conclusion
Though strengthening of the position of thresholds
and their application almost mandates that any
special circumstances, such as the unstable patient,
the dynamics of surgical bleeding or those at risk
of covert cardiovascular problems
Require close monitoring and individualized
trade-off decisions between the risks of anemia vs.
the risks and benefits of transfusion