BLOOD TRANSFUSIONSBLOOD TRANSFUSIONS

Dr. Tamara Wagenheim

INTRODUCTIONINTRODUCTION

RBC Transfusion dates back to 17th century70 years ago – mainstay of clinical practiceHuge advances in surgical and medical

practice1980’s concerns of transfusion related

infection

RBC transfusion - rationaleRBC transfusion - rationale

O2 delivery = cardiac output x O2 content

Restore oxygen delivery, preventing tissue hypoxia

Treatment of anaemia

ANAEMIAANAEMIA

Risk – harm caused by decrease in the O2 carrying capacity and plasma volume

Common in critically ill Causes:

1. Phlebotomy: “ nosocomial anaemia” “medical vampires”

2. Occult blood loss3. Inappropriate production of RBC : blunted EPO

response

ADVANTAGE VS ADVANTAGE VS DISADVANTAGEDISADVANTAGE

ADVANTAGES

1. TREATMENT OF ANAEMIA

2.RESTORE RC MASS, PREVENTING TISSUE HYPOXIA

DISADVANTAGES

1.TRANSFUSION RISKS

2.ADVERSE EFFECTS OF RC STORAGE

TRANSFUSION: TRANSFUSION: WHO?? WHEN??WHO?? WHEN??

CRIT study - Transfusion triggers drive transfusion decisions Downward revision of infusion trigger TRICC trial by Hebert et.al : liberal( 10g/dl) vs restrictive(7g/dl) transfusion threshold Overall hospital mortality lower in the restrictive group 30 day mortality lower in those < 55yrs Patients with active ischaemic cardiac disease benefited from

liberal transfusion threshold Therefore TRICC study showed 7g/dl threshold- most

appropriate transfusion threshold in critically ill patients

EFFECTS OF STORED EFFECTS OF STORED BLOODBLOOD

Storage of blood – cause of increase morbidity and mortality

Increased duration of storage associated – – Increase mortality– Increased length of hospital stay– Multi organ system failure– Impaired o2 utilization– Increased incidence of infection:- nosocomial infection

-TRIM WBC and accumulation of WBC derived cytokines-

increase morbidity and mortality

Effects of stored blood cont.Effects of stored blood cont.

Morphologic and biochemical changes ATP deprivation: – loss of surface/ volume ratio

– increase osmotic fragility– loss of deformity

2,3, DPG depletion WBC- increase haemolysis, and k leakage RBC adhesion with increased storage duration

RISKS OF BLOOD RISKS OF BLOOD TRANSFUSIONSTRANSFUSIONS

1. INFECTIONS: viral, bacterial2. MISMATCH: ABO incompatibility3. METABOLIC: acidosis, hyperkalaemia4. HYPOTHERMIA5. TRALI6. DILUTIONAL COAGULOPATHY

VIRAL TRANSMISSIONVIRAL TRANSMISSION

HIV– 1982/83- first transfusion related HIV infection– 1985- implementation of HIV ab test– 1995- p24 antigen

HEPATITIS B: hep b surface ag test led to decrease

in transfusion transmitted hep b HEPATITIS C: HCV antibody test HEPATITIS A: uncommonly ass. with blood transfusions CMV: oncology patients

BACTERIAL INFECTIONSBACTERIAL INFECTIONS

Most common organism – Yersinia enterocolitica

Bacterial contamination of platelets – common

RARELY- EBV, Lyme Disease, Brucellosis, Toxoplasmosis, Chagas Disease, West Nile Virus

MISMATCHMISMATCH

Mistransfusion- blood transfused to other than the intended recipient

USA: 1 in 14000 , 1 in 18000 in UK50 % errors in clinical arena30 % lab errors

TRALITRALI

Transfusion Related Acute Lung Injury Acute respiratory distress syndrome within 4

hours after transfusion Dyspnoea and hypoxaemia Approximately 1 in 5000 transfusions Mechanisms:

1. Donor antibodies react with recipients neutrophils – increased permability of pulmonary microcircultaiom

2. Storage of blood – rise of reactive lipid products

SUMMARYSUMMARY

Anaemia is common in critically ill patients Increased morbidity and mortality associated with anaemia

and transfusions Transfusion trigger of 7g/dl is most appropriate for

critically ill patients Transfusion trigger of 10g/dl for patients with active

ischaemic cardiovascular disaese Duration of RBC storage may have adverse effects Advances in blood safety, esp transfusion transmitted viral

infections Consider alternatives to RBC transfusion