A homicide may be considered justified if it is done to prevent a very serious crime, such as rape, armed robbery, manslaughter or murder. The victim must reasonably believe, under the totality of the circumstances, that the assailant intended to commit a criminal act that would likely result in the death or life-threatening injury of an innocent person. A homicide performed out of vengeance, or retribution for action in the past, or in pursuit of a "fleeing felon" (except under specific circumstances) would not be considered justifiable. In many states, given a case of self-defense, the defendant is expected to obey a duty to retreat if it is possible to do so. In the states of Alabama, Alaska, Arizona, California, Colorado, Connecticut, Florida, Georgia, Hawaii, Indiana, Kansas, Kentucky, Louisiana, Maine, Maryland, Massachusetts, Michigan, Mississippi, Missouri, Montana, New Jersey, North Carolina, Ohio, Oklahoma, Oregon, Pennsylvania, Rhode Island, South Carolina, Tennessee, Texas, West Virginia, Washington, Wyoming and other Castle Doctrine states, there is no duty to retreat in certain situations (depending on the state, this may apply to ones home, business, or vehicle, or to any public place where a person is lawfully present). Preemptive self-defense, in which one kills another on suspicion that the victim might eventually become dangerous, is not justifiable.
Hyperglycemia can also contribute to hyperkalemia by causing hyperosmolality in extracellular fluid, increasing water diffusion out of the cells and causes potassium to move alongside water out of the cells also. The co-existence of insulin deficiency, hyperglycemia, and hyperosmolality is often seen in those affected by diabetic ketoacidosis. Apart from diabetic ketoacidosis, there are other causes that reduce insulin levels such as the use of the medication octreotide, and fasting which can also cause hyperkalemia. Increased tissue breakdown such as rhabdomyolysis, burns, or any cause of rapid tissue necrosis, including tumor lysis syndrome can cause the release of intracellular potassium into blood, causing hyperkalemia.Beta2-adrenergic agonists act on beta-2 receptors to drive potassium into the cells. Therefore, beta blockers can raise potassium levels by blocking beta-2 receptors. However, the rise in potassium levels is not marked unless there are other co-morbidities present. Examples of drugs that can raise the serum potassium are non-selective beta-blockers such as propranolol and labetalol. Beta-1 selective blockers such as metoprolol do not increase serum potassium levels.Exercise can cause a release of potassium into bloodstream by increasing the number of potassium channels in the cell membrane. The degree of potassium elevation varies with the degree of exercise, which range from 0.3 meq/L in light exercise to 2 meq/L in heavy exercise, with or without accompanying ECG changes or lactic acidosis. However, peak potassium levels can be reduced by prior physical conditioning and potassium levels are usually reversed several minutes after exercise.