Blood Transfusion in ICU
8/2/11
PY Mindmaps
SP Notes
- anaemia common in ICU
- tendency to more restrictive strategy c/o increased morbidity associated with transfusion
- general attempts to minimize the requirement for blood transfusion should be pursued:
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stopping bleeding early
stop unnecessary anticoagulation
minimising venesection
treat hypothermia and acidosis
GI prophylaxis
Fe2+
nutrition
consideration of EPO therapy
use of FVIIA
- transfusion triggers are dependent on many variables:
1.
2.
3.
4.
evidence of bleeding and stability to patient
reason for admission (trauma, GIH)
patient wishes (Jehovah’s witness)
co-morbid conditions (such as ischaemic heart disease)
BLEEDING
- lower threshold to transfuse
- adults: aim to keep Hb > 80 g/L until bleeding controlled
- trauma patient:
-> haemostatic resuscitation: early products in a 1:1:1 ratio (RBC:platelets:plasma)
-> permissive hypotension
-> damage control surgery
-> avoid hypothermia, acidosis and coagulopathy
NON-BLEEDING
- controversial
TRICC trial (NEJM, 1999)
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critically ill, normovolaemic, non-bleeding
MRCT
n = 838
restrictive (70g/L) vs liberal groups (100g/L) as transfusion thresholds
no difference in mortality
increased complications in liberal strategy group (APO, ARDS)
under powered
prior to leukodepletion
Jeremy Fernando (2011)
TRACS trial (JAMA, 2010)
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post cardiac surgical patients
RCT
n = 502
HCT 30% vs HCT > 24%
no difference in mortality and severe morbidity
large separation between groups not achieved
high base line event rate
number of RBC’s transfused was an independent risk factor for clinical complications
CONTROVERSIAL ISSUES
Storage lesion
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increased peri-operative complications
organ failure
sepsis
mortality
VTE
Old vs New blood
- decreased deformability -> impedes microvascular flow
- depletion of 2, 3 DPG -> left shifted oxy-Hb dissociation curve -> reduces O2 delivery
- increased adhesiveness and aggregability
- reduced concentration of NO
- reduced ATP -> reduced ability to maintain biconcave shape
- accumulation of proinflammatory bioactive substances
- haemolysis over time
- progressive increase in K+ concentration (20mmol/L @ day 28) -> despite this
hyperkalaemia uncommon complication
- progressive acidaemia (pH 6.7 @ day 28)
- hypomagnasaemia
- citrate exposure -> hypocalcaemia
Leucodepletion
- decreases risk of TRALI
- reduction in non-haemolytic transfusion reactions
- reduction in CMV transmission
- improved chance of finding an organ transplant match if required
- reduction in storage lesion effect
- reduction in graft vs host disease
- reduction in mortality after universal leukodepletion in cardiac surgical, orthopaedic and
trauma populations (Hebert, JAMA, 2003)
EPO
- decreases transfusion requirements
- increased thrombotic complications
- being investigated in trauma and traumatic brain injury
Jeremy Fernando (2011)
FVIIa
- stops bleeding but increased risk of thrombosis and embolic disease
Undefined threshold for IHD patients
MY APPROACH
- minimise transfusion requirements using other means
- if bleeding: transfuse aggressively until bleeding controlled (avoid hypothermia, acidosis and
coagulopathy).
- if not bleeding: restrictive strategy in those who can tolerate it and more liberal in those
that have evidence of ischaemic end-organ dysfunction.
- ideally use new, leucodepleted blood
Jeremy Fernando (2011)