Hypoxic encephalopathy after heart valve replacement: etiology and pathogenesis, diagnostic criteria and treatment

Reviewed in this paper are modern approaches in the intensive therapy of acute hypoxic encephalopathy developing in a number of occasions after the heart valve replacement surgery. The study is based on the results of neurological, neuropsychological and neurophysiological (EEG) examinations of 240 patients who underwent heart valve replacement surgery under cardiopulmonary bypass conditions complicated later by the development of hypoxic encephalopathies of varying severity and who received complex intensive care. Relying on many years of experience in the treatment of heart surgery patients in whom manifestations of encephalopathy developed in the early postoperative period, or were delayed, we have formulated the following algorithms of therapy. (1) Maintenance of normal blood gas: Hb>100 g/L, pH – 7.45, PaCO2 – 35 mmHg. (2) Maintenance of hemodynamics: ABPsystolic>90 mmHg. (3) Supplying fluids and electrolytes: isoosmolar infusion solutions, adding of KCl and MgSO4 to the infusion. (4) Antiedemic therapy: 15% mannitol or 40% glycerol solution. (5) If necessary (in case of psychomotor agitation, seizures), short-acting barbiturates (sodium thiopental), neuroleptics (haloperidol), propofol. No benzodiazepines in case of psychoses (6) Cerebral metabolism stimulation (not earlier than 48 hours after surgery) with cholinomimetics, nootropics, cerebral blood flow protectors. Cholinomimetics are allowed on the first day after surgery. This algorithm and the above-mentioned groups of drugs, especially central cholinomimetics, allow for correcting the neurocognitive impairment in the discussed group of patients quickly and effectively.