Biochemical indices of cerebral ischemic injury

Abstract

Hypoxanthine, creatine kinase (CK), lactate, pyruvate and potassium were determined in spinal fluid obtained by repeated lumbar punctures in patients who remained comatose (n = 10) and in patients who regained consciousness after cardiac resuscitation (n = 11).

Hypoxanthine concentrations increased 0–5 h after resuscitation to 18.7 ± 6.7 μmol/l, (mean ± SD) in patients (n = 6) who regained consciousness and to 51.7 ± 43.9 μmol/l, (mean ± SD) in patients (n = 8) who remained comatose. In all the patients the hypoxanthine concentrations returned within 20 h towards the normal values 6.3± 1.4 μmol/l (mean ± SD) as determined in 23 control subjects.

The release of CK to the spinal fluid occurred later with maximal values 24–48 h after resuscitation in those who died, and with no increase or moderate increase in those who regained consciousness/The concentrations of lactate, pyruvate and potassium increased to some extent, but did not separate between those who remained comatose and those who regained consciousness.

An extensive increase in hypoxanthine concentrations in the patients who subsequently died and had increased CK catalytic concentrations indicates a relationship between the extent of cerebral damage and hypoxanthine release. Hypoxanthine concentrations increased early also in patients with less severe brain disturbance and most likely therefore, is a sensitive parameter for brain hypoxia. The combined measurements in the spinal fluid of hypoxanthine and CK, 0–5 and 24–48 h respectively after transient cardiac arrest, are of diagnostic and prognostic value. This is not further improved by the simultaneous determinations of lactate, pyruvate or potassium.

Key Words:

• cardiac arrest
• cerebral hypoxia
• creatine-kinase
• hypoxanthine
• lactate
• potassium
• pyruvate
• spinal fluid