A comparison of cerebral and venous microdialysis during experimental hypothermic antegrad cerebral perfusion.

Authors:Jonsson O, Tovedal T, Zemgulis V, Lennmyr F, Hillered L,

Thelin S.

Department of Cardiothoracic surgery and anesthesiologyDepartment of Neuroscience, Neurosurgery

Uppsala University Uppsala University Hospital, Sweden

SACP Selective Antegrade Cerebral Perfusion

A Carotis communis

Aortic cannula

Clamps

Microdialysis

Lactate/pyruvate

Lactate/glucose

Background

• To encircle any signs of energy metabolic crisis and cellular distress during SACP flows between 6 ml/kg/min and 4 ml/kg/min.

• Can intravenous microdialysis in the sagittal sinus reveal global cerebral metabolic changes not detected by the brain microdialysis catheter.

Aims

• To investigate the effects of two SACP flow levels (6 and 4 ml/kg/min) on the development of cerebral ischemia.

• To evaluate the agreement and correlation between microdialysis markers harvested from the brain and the sagittal sinus.

Method

• Randomized study• 3 groups• 18 pigs (0 excluded)• Microdialysis (Cerebral, Sinus sagittal)• NIRS (Near infrared spectroscopy)• Cooling temperature 20oC

Experimental protocol

Group 1(○) SACP 4 ml/kg/min increased to 6 ml/kg/min/

Group 2 (∆) SACP 6 ml/kg/min decreased to 4 ml/kg/min

Group 3 (●) Control

0 30 60 90 120 150 1800

50

100

150

CPBCooling SACP SACP

S vO 2A

Time (min)

%

0 30 60 90 120 150 18060

80

100

120

140

CPBCooling SACP SACP

TOI relative

* *

B

Time (min)

%

0 30 60 90 120 150 1800

20

40

60

80

100

CPBCooling SACP SACP

MAPC

Time (min)

mm

Hg

0 30 60 90 120 150 1800

5

10

15

CPBCooling SACP SACP

Blood lactate

* *

D

Time(min)

µmol

/l

ResultsNIRS tissue oxygen index (TOI)

ResultsMicrodialysis from the brain

0 30 60 90 120 150 1800

2

4

6

A. Glucose CNSCPB

Cooling SACP SACP

Time (min)

mm

ol/l

0 30 60 90 120 150 1800

2

4

6

8

CPBCooling

SACP SACP

B. Lactate CNS

*

Time (min)

mm

ol/l

0 30 60 90 120 150 1800

100

200

300

CPBCooling SACP SACP

C. Pyruvate CNS

*

Time (min)

µmol

/l

0 30 60 90 120 150 1800

20

40

60

80

CPBCooling SACP SACP

D. L/P ratio CNS

*

Time (min)

0 30 60 90 120 150 1800

50

100

150

E. Glutamate CNSCPB

Cooling SACP SACP

Time (min)

µmol

/l

0 30 60 90 120 150 1800

50

100

150

200

250

CPBCooling SACP SACP

F. Glycerol CNS

Time (min)

µmol

/l

Results Microdialysis from the sagittal sinus

0 30 60 90 120 150 1800

5

10

15

A. Glucose SSCPB

Cooling SACP SACP

Time (min)

mm

ol/l

0 30 60 90 120 150 1800

2

4

6

8

10

12

CPBCooling SACP SACP

B. Lactate SS

Time (min)

mm

ol/l

0 30 60 90 120 150 1800

100

200

300

CPBCooling SACP SACP

C. Pyruvate SS

Time (min)

µmol

/l

0 30 60 90 120 150 1800

20

40

60

80

100

120

CPBCooling SACP SACP

D. L/P ratio SS

Time (min)

0 30 60 90 120 150 1800

50

100

150

200

250

CPBCooling SACP SACP

E. Glutamate SS

Time (min)

µmol

/l

0 30 60 90 120 150 1800

200

400

600

800

CPBCooling SACP SACP

F. Glycerole SS

*

*

Time (min)

µmol

/l

Probably the effect of circulatory arrest

Results Bland Altman

Results Correlation and Agreement

Table 3. Spearman’s correlation, bias, and limits of agreement between cerebral and sagittal sinus MD samples (n=119).

Comparison Correlation (r) Bias Limits of agreement p value

Glucose 0.41 - 3.8 - 9.2 to + 1.6 <0.01

Lactate 0.25 - 2.1 - 6.6 to + 4.5 0.08

Pyruvate - 0.02 - 35.7 -179.4 to + 108.0 0.87

Urea 0.32 - 0.7 - 2.2 to + 0.8 0.02

L/P ratio - 0.02 - 5.8 -49.0 to + 37.4 0.88

L/G ratio 0.15 2.0 - 6.3 to + 10.4 0.30

Glutamate 0.11 - 49.0 -152.9 to + 54.9 0.45

Glycerol 0.03 80.9 -71.4 to + 233.3 0.85

Conclusion

• An SACP flow of 6 ml/kg/min preserves cerebral metabolism according to cerebral microdialysis and NIRS.

• An SACP flow of 4 ml/kg/min induces early signs of disturbed energy metabolism.

• Microdialysis from the sagittal sinus is a feasible methode for monitoring biomarkers of global cerebral perturbations,

• But in the present model correlation with parenchymal measurements were poor and no agreement could be demonstrated.