Concurrent quantification of tissue metabolism and blood flow via 2 h/ 31 P NMR in Viva iii. alterations of muscle blood flow and metabolism during sepsis

In the conclusion of this series of reports, the application of 31 P/ 2 H NMR to investigate the pathophysiology of sepsis in rat hindlimb muscle is demonstrated. Sepsis decreased muscle [PCr] by 18%, 18 ± 4 SD vs 22 ± 4 SD mmol/kg tissue wet wt ( P = 0.01) in control rats but [ATP] was unchanged, 6 mmol/kg tissue wet wt ( P = 0.2). The derived free cytosolic [ADP] in the two groups was similar, [ADP] septic = 0.023 ± 0.004 SD and [ADP] control , = 0.021 ± 0.003 SD mmol/kg tissue wet wt, and not statistically different (P =0.14). Likewise [P i ] in the septic and control groups was not statistically different, [P i ] septic = 1.1 ± 0.5 SD and [P i ] control , = 1.2 ± 0.4 SD mmol/kg tissue wet wt ( P = 0.2). Septic rats presented the symptom of respiratory alkalosis evidenced by elevated blood pH. Sepsis decreased muscle blood flow by 33%, P = 0.003, but examination of individual subjects did not demonstrate a correlation with the reduction in [PCr]. Thus, a metabolic energy deficit caused by cellular ischemia/hypoxia is not a likely cause of cellular abnormality in rat hindlimb muscle during sepsis.