Hydrogen Sulfide as Prognostic Factor

Hydrogen sulfide (H2S), better known as a poisonous gas, has lately emerging as a third gaseous transmitter in mammals, next to nitric oxide (NO) and carbon monoxide (CO). H2S is present in most human tissues in concentrations up to 50 μM. Most of it is synthesized in brain, cardiovascular system, kidneys and liver. In human tissues H2S is synthesized from L-cysteine by two enzymes cystathionine-γ-lyase and cystathionine-β-synthase. H2S works by stimulating ATP sensitive potassium channels and is involved in regulation of vascular tone, myocardial contractility, insulin secretion and neurotransmission. In numerous animal models, H2S deficiency was shown in arterial and pulmonary arterial hypertension, Alzheimer's disease and liver cirrhosis. Increased production and higher serum concentrations were shown in inflammatory diseases, septic shock and stroke.

Most of studies so far were conducted on animals and already show some therapeutic potentials. In available literature there have been no studies in humans focused on H2S concentrations in critically ill and its prognostic value.

Hypothesis We will test the hypothesis that higher serum H2S concentrations on admission to ICU are linked with higher mortality in patients with shock of any reason.

Serum H2S concentrations are related to treatment support with vaso-active drugs (noradrenalin, epinephrine).

Material and methods In the study we will include adult patients admitted to medical ICU due to shock of any reason. Shock is defined as systemic arterial pressure lower than 90mmHg or drop for systemic arterial pressure at least 40mmHg for 15minutes or more with elevation of serum lactate value.