What complication must be avoided when administering potassium parenterally?

When potassium is administered parenterally, one of the most significant complications that must be avoided is cardiac arrest. Potassium plays a critical role in maintaining the electrical activity of the heart. An excessive concentration of potassium in the bloodstream, known as hyperkalemia, can lead to dangerous cardiac arrhythmias and ultimately result in cardiac arrest. This is particularly concerning during intravenous administration because if potassium is infused too rapidly or inappropriately, it can cause a rapid rise in serum potassium levels.

It's essential to monitor how potassium is administered, ensuring that it is diluted appropriately and infused at a controlled rate. Continuous cardiac monitoring is often a standard practice during parenteral potassium administration to observe for any signs of arrhythmias early on. Therefore, the emphasis on preventing complications related to cardiac function makes cardiac arrest the most critical complication to guard against during this treatment.