Transcript Blood products - Vula

Blood Products in Critically ill Children
Shamiel Salie
Paediatric Intensive Care Unit
Red Cross Children’s Hospital,
University of Cape Town
1818 - Extracted 4 ounces of blood from the arm of
the patient’s husband with a syringe and
successfully transfused it
Anaemia in critically ill children
• Causes
– Chronic anaemia
– Overt and occult blood
loss
– Bone marrow
suppression from
diseases/treatment
– Inadequate erythropoietin
response to anaemia
Red Blood Cell Transfusions
• For decades considered to be a low risk
with obvious benefits
• 10/30 rule
• Restrictive use of blood since the 1980’s
What actually happens in PICU?
• 50% of children in PICU’s transfused
Bateman: Am J Resp Crit Care Med 2008
• Large variability in clinical practise
• Bedside observational studies
Gauvin 2000 & Armano 2005
– transfusion threshold ranges from 7 - 11 g/dl
• 30 North American PICU’s
– Pretransfusion Hb 9.7 g/dl
Bateman: Am J Resp Crit Care Med 2008
Physiological benefits of RBC
transfusions
• Tissue hypoxia may be due to low Hb
concentration, cardiac output or SaO2
• Oxygen delivery exceeds requirements
• Adaptive processes as oxygen delivery
decreases with anaemia
– Increased oxygen extraction
– Increased heart rate and stroke volume
– Preferential perfusion of head and heart at
the expense of splanchnic perfusion
• Altered physiological adaptation to low Hb
in critically ill children
– Increased metabolic rate in SIRS increases
oxygen consumption and lowers reserves
– Impaired LV function and vascular tone
restricts oxygen delivery and blood
redistribution
– Infants have high resting heart rates, which
limits the ability to increase cardiac output
Microcirculatory effects of
transfused RBC
• Global increase in oxygen delivery with
potentially decreased microcirculatory flow
– Increased blood viscousity
– Cytokines my cause vasoconstriction
– Low levels of 2,3 DPG shifts curve left,
impeding oxygen availability
– Decreased RBC membrane deformability
– Free Hb may bind NO causing vasoconstriction
Immunologic effects of RBC
transfusion
• Some evidence that it may cause
– Immune suppression by altering lymphocyte
reactivity
– Pro inflammatory: cytokines in unfiltered rbc’s
might trigger SIRS or multi organ failure
When should critically ill
children be transfused?
• 637 critically ill children
• Equivalence of restrictive strategy (Hb<7) and
liberal strategy (Hb <9.5)
• No difference in MODS, death, icu stay and sepsis
• 44% reduction in blood transfusions
• 50% of study children transfused
•
•
•
•
•
838 critically ill adults
Restrictive strategy (Hb<7) and liberal strategy (Hb <9)
Restrictive group had 54% fewer rbc units
Decrease mortality in adults who were less sick
Possible exceptions: unstable angina and MI’s
• 1269 Kenyan children hospitalized for malaria
English, Lancet 2002
– RBC transfusion decreased mortality in severe anaemia, <4g/dl
or if Hb < 5g/dl and dyspnoeic
- some benefits to keep Hb > 5 in hospitalized children
• Haemodynamically unstable children: Hb > 10
• De Oliveira et al (Intens. Care Med. 2008)
– children with severe sepsis
– significant reduction in 28 day mortality
(11% vs 39%, p=0.002) and new organ failure
– targeting SVC sats > 70% using fluids, inotropes and
blood transfusions keeping Hb > 10g/dl
• Similar outcomes in adults using goal directed
therapy Rivers et al, NEJM 2001
• Children with severe congenital heart disease and
traumatic brain injuries might need higher Hb’s
Transfusion related acute lung
injury (TRALI)
• Aetiology poorly understood
• Diagnostic criteria
– Acute lung injury occurring within 6 hours
of a transfusion
– No signs of fluid overload
– Bilateral lung infiltrates on cxr
• Usually resolves within 48 hours
Leukocyte reduced RBC’s
• Reduces leukocytes by up to 99%
• reduces the number of cell associated
viruses: cmv, herpes and ebv
• May reduce transmission of prions and
parasites and incidence of TRALI
Fresh Frozen Plasma
• Treatment of DIC and replacement of
clotting factor
• Effectiveness judged by cessation of
bleeding.
• aPTT and INR poor predictor of bleeding
Gajic: Crit Care Med 206
• Not recommended as a volume expander
Platelets
• Thrombocytopenia and qualitative platelet
defects impairs ability to form platelet plugs
• Risk of massive bleeding when platelet
count < 10 and IVH when platelets <1
• No scientific basis for keeping platelets > 20
Cryoprecipitate
• Rapid increase in fibrinogen levels in
patients with DIC and active bleeding
• Meta-analyses of 24 studies, 1419 patients
• 6% increase in mortality or
‘1 death for every 17 patients given albumen’
• Meta-analysis of 55 trials, 3504 patients
• No difference in mortality
• Nearly 7000 patients
• No significant difference in mortality
• Similar rates of secondary outcomes
– Survival time, organ dysfunction, duration of
mechanical ventilation, length of icu and hospital stay
• Albumin to saline ratio 1: 1.4
Conclusions
• Stable critically ill children can support
an Hb > 7
• Maintain Hb > 10 in haemodynamically
unstable children, those with significant
cardiovascular disease and traumatic
brain injuries
Conclusions
• Advantages to using leukocyte
reduced blood
• Platelet transfusion thresholds not
evidence based
• Prophylactic use of FFP is
controversial
Questions