Nuclear magnetic resonance spectroscopy study of human brain after cardiac resuscitation.

We used 31P nuclear magnetic resonance spectroscopy to study the cerebral metabolic function of eight patients with severe postischemic anoxic encephalopathy secondary to cardiac arrest. Spectroscopy was performed at 18 +/- 13 and 64 +/- 20 hours after resuscitation. Glasgow Coma Scale scores at the time of initial and repeat spectroscopy were 3.6 +/- 1.2 and 3.5 +/- 1.2, respectively. In those patients whose spectra were of adequate quality to monitor pH, all demonstrated tissue alkalosis in at least one brain region. The mean brain pH at initial spectroscopy was 7.14 +/- 0.09 and was significantly alkalotic when compared with age- and sex-matched normal controls (pH = 6.98 +/- 0.04, p less than 0.0001). Five of the eight patients showed at least one region of persistent alkalosis at repeat spectroscopy, whereas one patient demonstrated severe acidosis with a pH of 6.42. Spectra demonstrated marked metabolic heterogeneity, ranging from normal in appearance to complete obliteration of all high-energy phosphates with only inorganic phosphate remaining.