Transcript Blood Utilization in ECMO Patients

Blood Utilization in
ECMO Patients
Omar Alsuhaibani
Transfusion Medicine
Journal Club
Background
• EXTRACORPOREAL MEMBRANE OXYGENATION
(ECMO) is a technique, pioneered by Bartlett et
al., for the treatment of severe respiratory failure,
especially in neonatal patients.
• The procedure permits oxygenation of blood
while bypassing the lungs, thereby allowing
resolution of the primary pulmonary pathology.
• A modified heart-lung machine is used.
Bartlett et al., Surgery, 1982;92:425-33
Background
• In veno-arterial ECMO, blood is collected from
the right atrium via the external jugular vein,
passed through a membrane oxygenator and
heat exchanger, and returned to the systemic
circulation through a perfusion cannula, usually
via the right common carotid artery.
• Venovenous ECMO, in which blood is returned
through a perfusion cannula via the femoral vein,
has been attempted but is not the method of
choice.
McCoy-Pardington et al., Transfusion , 1990;30:307-309
Background
ECMO has particular application for infants with
impaired pulmonary function associated with:
• congenital diaphragmatic hernia (CDH)
• meconium aspiration (MA)
• persistent fetal circulation (PFC)
• respiratory distress syndrome (RDS)
• sepsis.
McCoy-Pardington et al., Transfusion , 1990;30:307-309
Background
• While ECMO has been employed most widely
for treatment of severe respiratory failure in
neonatal patients, it more recently has been
utilized also to treat respiratory failure in
adults.
• In both age groups, the goal of the procedure
is to oxygenate the blood without involving
the lungs.
Butch et al., Transfusion,1996;36:61-63
Background
• As in the pediatric group, pulmonary
dysfunction in adults has been the
clinical condition occasioning ECMO.
• These patients are considered to have an
estimated 90% risk of mortality with
conventional treatment.
Background
• ECMO in neonatal patients does not impose a
significant burden on a hospital transfusion
service.
• In contrast to the situation with neonates, it
seemed that ECMO performed on adult
patients imposed a considerably greater
burden on hospital blood banks and required
a much greater level of blood component
support.
Butch et al., Transfusion,1996;36:61-63
Objectives
Primary objectives
(i) describe the red blood cell, platelet, fresh-frozen plasma
(FFP) and cryoprecipitate requirements of adult patients in
our institution while they were undergoing ECMO.
(ii) determine independent clinical variables that may be
associated with increased red blood cell, platelet and FFP
transfusions during ECMO.
Secondary objectives
assess the mortality of adult patients who underwent ECMO
and to evaluate if this procedure helped to improve overall
survival.
Patient Selection
• All patients aged 16 years and above who had
undergone ECMO at the National Heart Centre,
Singapore, between June 2003 and September 2006.
• Patients with incomplete transfusion or clinical
records were excluded.
• Exclusion criteria included active uncontrollable
bleeding or potential for severe bleeding, poor
quality of life, septic shock and morbid obesity.
ECMO Guidelines
(1) Severe respiratory failure refractory to conventional
treatment and support.
(2) Post-cardiotomy shock:
ECMO is instituted in patients who have undergone cardiac
surgery and have good chances of recovery, but are unable
to be weaned off cardiopulmonary bypass (CPB) despite
conventional inotropic support and intra-aortic balloon
pump. ECMO will be replaced with a long-term device, for
example, ventricular assisted device (VAD), if myocardial
recovery does not occur within the short term and if the
patient is a heart transplant candidate.
cont.
ECMO Guidelines
(3) Acute cardiogenic shock resulting from myocardial
infarction, myocarditis, intractable cardiac arrhythmia, etc. as
a bridge to VAD implantation, cardiac transplantation, other
intervention or myocardial recovery.
(4) Massive PE as a bridge to surgical pulmonary embolectomy.
(5) Heparin to maintain an activated clotting time of 180–220
seconds.
(6) Patients’ haemoglobin (Hb) and platelet counts should be
kept at a minimum of 10 g/dl and 100 × 109/l, respectively.
Clinical and transfusion information
• A retrospective review of the clinical and transfusion records
of all selected patients.
• Information on the total number of red blood (RBC) cell units,
random platelet units, single-donor aphaeresis platelet
concentrates, FFP and cryoprecipitate received by each
patient during the days of ECMO was obtained.
• Universal leucoreduction is not practiced in Singapore.
• The average daily RBC, platelet, FFP and cryoprecipitate, as
well as the maximum daily RBC and platelet received by each
patient were also calculated.
Clinical and transfusion information
• Demographic and clinical variables that may
influence RBC, platelet and FFP requirements
were recorded for each patient.
• Demographic variables included
- age
- gender
- ethnic group
- body surface area (BSA)
Clinical and transfusion information
Clinical variables included
- co-morbidities
- underlying diseases necessitating ECMO
- renal failure
- sepsis during ECMO
- bleeding during ECMO
- sites of bleeding
- ECMO indications and types
- overall mortality
- mortality during ECMO
- whether surgeries were performed before and/or during ECMO
- Hb and platelet counts before and during ECMO
Statistical analysis
• All categorical variables were compared using Fischer-exact
test or χ2-test
• Continuous variables (except BSA) were analysed using
Mann–Whitney U-test.
• Correlation between two continuous variables (except BSA)
was assessed using Spearman’s correlation coefficient.
• BSA was the only continuous variable that fulfilled tests of
normality, and was analysed using two sample t-test or
Pearson’s correlation coefficient when relevant.
• All analyses was done using SPSS
Results
• Forty-one patients (median age 50 years) underwent 42
ECMO sessions for respiratory failure (16·7%), cardiogenic
shock (76·2%) or massive pulmonary embolism (7·1%).
• They received 569 red blood cells, 852 platelets, 126 freshfrozen plasma (FFP) and 220 cryoprecipitate in total during
median ECMO duration of 5 (1–15) days.
• On multivariate analysis, average daily red blood cell
transfusion increased with nadir haemoglobin (Hb) during
ECMO (Hb nadir) of < 7·5 g/dl (P < 0·001).
Results
• Average daily platelet transfusion increased with
- recent antiplatelet agents (P = 0·015), and
- maximum Hb decline of > 5·5 g/dl during ECMO (P = 0·011).
• Average daily platelet transfusion > 3 units was also
associated with increased ECMO duration (P = 0·024).
Results
• Average daily FFP transfusion was increased in patients with
hypertension (P = 0·007) and Hb nadir < 7·5 g/dl (P = 0·050).
• Patients with sepsis (P = 0·009) or without surgery (P = 0·009)
had increased ECMO duration, which correlated positively
with total transfusion requirements during the entire ECMO
session.
• ECMO improved mortality of patients with fulminant
myocarditis, respiratory failure and massive pulmonary
embolism.
Conclusion
• Adult ECMO patients with lower Hb nadir require
more daily red blood cell and FFP.
• Hypertension increases daily FFP requirements.
• Recent antiplatelet agents, larger Hb decline and
longer ECMO duration increase daily platelet
requirements.
• Patients with sepsis or on ECMO for medical reasons
have longer ECMO duration, which is associated with
total transfusion requirements.
Conclusion
• The transfusion demands of adult ECMO
patients are high.
• Measures may be instituted earlier, and close
cooperation between the managing clinician
and the transfusion physician is necessary to
ensure good transfusion support for these
patients without adding excessive burden to
the blood bank.
Thank you