Energy metabolism of the liver in brain dead dogs assessed by 31P-NMR spectroscopy and arterial ketone body ratio.

The changes in hepatic energy state were assessed by 31P-nuclear magnetic resonance spectroscopy (31P-MRS) and arterial ketone body ratio (AKBR) in brain dead dogs. 31P-MRS and AKBR were measured before and at 3 hours after brain death. Wiggers' shock model was employed to compare the energy metabolism during hypotension. 1) The brain death model: Systemic blood pressure changed from 178.3/115.0 mmHg (mean) in the control period, to 259.5/162.5 mmHg during Cushing phenomenon (CU period) and to 63.3/51.7 mmHg after completion of brain death (BD period). beta-ATP/Pi increased from 1.27 +/- 0.14 (mean +/- SEM) to 1.46 +/- 0.16 in the early CU period, and then decreased to 1.11 +/- 0.15 at 60 minutes after BD, followed by a gradual increase to 1.33 +/- 0.13 at 3 hours after BD. Intracellular pH (pHi) increased alkaline to the control value. AKBR decreased from 1.10 +/- 0.26 to 0.46 +/- 0.15 in the CU period (p less than 0.05) and then increased to 1.48 +/- 0.25 after BD. 2) Wiggers' shock model: Systemic blood pressure was 190.0/112.5 mmHg in the control period, 83.8/51.3 mmHg during exsanguination (EX period) and 185.0/117.0 mmHg after retransfusion (RT period). beta-ATP/Pi decreased from 1.17 +/- 0.13 to 0.61 +/- 0.10 in the EX period (p less than 0.05) and increased to 1.37 +/- 0.08 in the RT period. The pHi deviated from 7.33 +/- 0.07 to 6.82 +/- 0.14 in the EX period (p less than 0.01) and to 7.51 +/- 0.21 in the RT period. AKBR decreased from 1.00 +/- 0.11 to 0.21 +/- 0.04 in the EX period and increased to 1.08 +/- 0.12 in the RT period. The energy metabolism of the liver was well maintained in the state of brain death in spite of remarkable hypotension, although that was not the case with Wiggers' shock model. It was suggested that the combination of 31P-MRS and AKBR was useful for the evaluation of graft liver viability.