Effects of Shed Mediastinal Blood on Cardiovascular and Pulmonary Function:

A Randomized and Double Blind Study

Effects of Shed Mediastinal Blood on Cardiovascular and Pulmonary Function:

A Randomized and Double Blind Study

Presented by: Maggie SavelbergOn: February 18, 2009

Presented by: Maggie SavelbergOn: February 18, 2009

4

3

2

1Problem: Suction Blood Good?

Objective & Methods

Results & Future Implications

Limitations of Paper

Overview:Overview:

Identification of a Problem I:Identification of a Problem I:

Recirculation and retransfusion of shed mediastinal and pericardial blood (since 1978)has been associated with decreased homeostasis and increased morbidity

Principle Findings (1995) : - ↑ thombin-antithrombin III levels - significant ↓ in post-op blood - ↑ tissue-type plasminogen activator loss (p<0.005) - ↑ fibrin degradation products - ↓ blood product use - ↑ free plasma hemoglobin

Retransfusion of sucker blood = ↑ wound bleeding

Ann Thorac Surg 1995;59:901-907

Identification of a Problem II:Identification of a Problem II:

Perfusion 2000;15:427-431

Principle Findings (2000) : - ↑ endotoxin in pooled pericardial blood (p<0.05)

- proposed reinfusion as a possible contributor to overall SIR

- ↑[endotoxin] = respiratory failure, renal failure, bleeding disorders, and neurological dysfunction.

Identification of a Problem IV:Identification of a Problem IV:

Annals of Thoracic Surgery 2004;78:54-59

Principle Findings (2004) : - significant ↑ TNF-α , IL-6, C3a in

retransfusion group (p<0.001)

- ↑ volume retransfusion blood = ↑ TNF-α levels = ↓ Hgb post-operatively

Identification of a Problem III:Identification of a Problem III:

Interactive Cardiovascular and Thoracic Surgery 2009;

Principle Findings (2008) : - lipid-microemboli size ranged from 10- 60µm which have been linked to poor

neurological outcome following CPB. - ↑ concentration following cannulation

and in shed blood from the pleura

- Found in arterial side of HLM circuit

↑ lipid microemboli in pericardial sucker blood bleeding = link to ↓ neurological outcome

I. Objective:I. Objective:

Determine within subset of Cardiotomy Trial patients the effects of cardiotomy blood processing on identified endpoints;

a) cardiovascular function b) pulmonary mechanics c) gas exchange

Annals of Thoracic Surgery 2008;86:1167-74

Clinical identifiers of patient status/health

II. Methods:II. Methods: Study Design

Patient Population:

- 266 patients - non-emergent CABG and/or AV replacement - on-pump CPB - exclusions: neurological deficits

pre-op coagulopathybleeding diathesisthrombocytopeniarenal insufficiencyhepatic insufficiency

- Control: received unprocessed shed mediastinal blood.

- Treatment: received processed shed mediastinal blood.

266 patients

136 133

77

Control Treatment

77

Additional Testing

II. Methods:II. Methods: Study Design

Randomization:

- computer generated randomization

- allocation presented in sealed envelope to perfusionist by research coordinator just prior to giving heparin before CPB.

- all members of the surgical team were unaware due to positioning of opaque drape

- intraoperative decisions to transfuse blood products were made by anesthesia who again, were unaware of treatment assignment.

II. Methods:II. Methods: Intraoperative Protocol Intraoperative Protocol

Interventional Plan:

CPB Strategy: - narcotic based anesthetic - heparin for ACT >400 sec - CPB (roller pump, 43µm art filter closed venous reservoir) - prime (1,300mL) RL solution - bypass flows maintained at 2.4 – 3.2 L/min/m2

- antegrade cardioplegia & topical cooling - body temperature 34ºC, re-warmed to 37ºC

Sucker blood↓

Cell Saver↓

LD Filter↓

Circuit↓

Patient

Study Interventions:

Treatment

Sucker blood↓

Circuit↓

Patient

Control

Baseline / Intraoperative characteristics similar

Cardiotomy blood volumecollected similar in both

groups (p= 0.21)

Patient

Population

III. ResultsIII. Results: A Summary: A Summary

Analyzed before, during and after CPB

No difference in indices of mechanical pulmonary function or

gas exchange b/t groups.

Pulmonary

Function

III. ResultsIII. Results: A Summary: A Summary

Variables Measured

Tidal Volume

Peak Inspiratory Pressure

Positive End Expiratory Pressure

Compliance

** Arterial pO2

** Pulmonary Shunt (Qs/Qt %)

** DO2 index

** Oxygen Extraction Ratio (%)

** Alveolar-arterial oxygen gradient

Impairments in red starred ** variables

(same in both the control and treatment groups)

Cardiovascular

Effects

III. ResultsIII. Results: A Summary: A Summary

↓ PVR + SVR

↑ Cardiac Index (p = 0.004)

↓ duration myocardial

Ischemia(p =0.02)

↑ hgb levels(p=0.003)

being in processed group

Processed

Sucker

Blood

Processed

● Unprocessed

multivariateanalysis revealedonly independent pre/intra operative

factors attributedto improved post-op

cardiac index.

↑ Unprocessed sucker volume = ↓ cardiac hemodynamics

Clinical

Outcomes

ResultsResults: A Summary: A Summary

No ∆ in mortality

↑ creatine kinase in unprocessed group BUTtroponin levels similar

ProcessedUnprocessed P-value

Conclusion: Conclusion: & Future Implications& Future Implications

Principle Findings :

- Processing (centrifugal washing & leukocyte depleting filtration) of cardiotomy blood

= no effect on mechanical pulmonary function = no effect on indices of pulmonary gas exchange

- However, significant hemodynamic changes were observed as a result of cardiotomy blood processing.

= ↓ PVR and SVR (approximately by 30%)= ↑ CI= trend toward ↓ ventilation time

- Individualized Perfusion: (tailored approach) Benefits may to process suctioned blood in patients with poor LV vs.

those with good LV function who are high risk of bleeding complications (further complicate bleeding by loss of PLT and coagulation factors from cell saver)

“Processing” consisted of both

centrifugal washing &

lipid/leukocyte reduction

To which do we attribute the outcomes?

Limitation #1 Limitation #2 Limitation #3

IV. Limitations:IV. Limitations:

Could have done the same

evaluation with a group of patients just discarding

suction blood if it is a small volume.

Use of cell saver associated with

loss of coagulation factors and PLTs.

Perhaps looking at chest tube loss

post-operatively, and blood product

use?

Please feel free to post questions/comments to OSCP site for

discussion.