What could have caused the loss of electrolytes in the neonate during the cardiac procedure?

The scenario involves the potential loss of electrolytes in a neonate during a cardiac procedure, and the correct answer points to the switch of sterile water with heparinized saline. This can lead to electrolyte imbalance because heparinized saline is a solution that may contain different concentrations of sodium and other electrolytes compared to sterile water, which does not contain any electrolytes.

When sterile water is used in place of a saline solution, it can lead to dilutional hyponatremia—where the sodium levels in the blood decrease due to excess water without any concurrent supply of sodium. In a surgical context, this can occur if the saline intended for irrigation or other uses is inadvertently replaced with plain sterile water, causing an imbalance as the body requires consistent electrolyte levels for proper physiological function.

In contrast, inadequate fluid intake and delayed electrolyte supplementation generally refer to poor management of fluids and nutrient administration, leading to gradual electrolyte changes rather than abrupt imbalances. While excessive digitalis could impact heart function and may lead to other complications, it is less directly associated with the immediate loss of electrolytes compared to the misuse of saline solutions in a procedure setting.