Acidaemia and hyperkalaemia following low-voltage electric shock in the anaesthetized cat

Plasma K+ and Na+ concentrations ( [K+], [Na+] ), gas tensions (PO2, PCO2), pH levels and lactate concentrations ( [lactate] ) were measured in blood samples obtained before and after applying low-voltage electric shocks (13-130 V a.c., 5-50 mA, 50 Hz) from forelimb to opposite hind limb in cats anaesthetized with pentobarbitone. The current intensities used did not induce any changes either in rectal temperature or in the electrocardiogram in post-shock periods. Marked reductions in pH, increases in [K+] and elevations in [lactate] relative to control values were measured in arterial blood samples following shocks lasting between 10 and 30 s, with the changes in pH and [lactate] more prolonged (45-90 min) than the [K+] alterations (5-10 min). Post-shock acidaemia and hyperkalaemia were significantly attenuated by neuromuscular blockade and were more pronounced in samples obtained from blood draining the skinned hind limb than in arterial blood. In the immediate post-shock periods both arterial and venous blood samples showed elevations in PCO2 and decreases in PO2 compared with control levels. No differences in [Na+] were noted in arterial and venous blood samples obtained before and after shocks. The sequelae of electric shocks noted in this study mainly arose from changes occurring in tetanically contracted muscles during the passage of current and similar residual effects would be expected to be present in human subjects in circumstances where victims of electrical accidents cannot release contact from a low-voltage source. Some of these sequelae may have relevance in explaining the 'delayed deaths' which occasionally follow human electrical accidents.