Question

Massive (and unfortunate) crush injuries present multiple problems for doctors in the emergency department- not only must they treat the injury, but there is also a distinct chance the patient’s heart will stop. This is due to the sudden acute hyperkalemia resulting for intracellular potassium stores in skeletal muscle cells leaking out through the damaged cell membranes. How would this sudden increase in ECF potassium affect the heart?

Group of answer choices

Increased ECF K⁺ concentrations would hyperpolarise cardiac myocytes preventing them from firing action potentials.

Due to the nature of the sodium/potassium ATP-ase, increasing ECF K⁺ would stall this pump leading to an indirect build-up of intracellular Ca²⁺.

Increased ECF K⁺ concentrations would cause cardiac myocytes to repolarise more quickly, potentially leading to ventricular fibrillation.

Increased ECF K⁺ concentrations would cause resting membrane potential in cardiac myocytes to become more positive.

Answer 1

Ans:- option d) is correct

d) Increased ECF K+ concentrations would cause resting membrane potential in cardiac myocytes to become more positive.

concept:- to understand this we should Frist know how resting membrane potential is formed .

during resting phase conc of k+ is more inside the cell and less outside the cell. So K + Diffuses out of the cell making a negative inside the cell.

now as due to injury K + conc increases in extra cellular fluid less K+ will diffuse out of the cell leading to a less negative RMP of cardiac muscle which will lead to more easy excitation of Cardiac muscle causing arrthymia and trachicardia... Ok increasing the change of heart failure.

Rx:- intravenous insulins along with glucose is use to treat Hyperkalemia.