USA Surgery Today

Although hyperkalemia is the most life-threatening disorder of potassium balance, hypokalemia is much more common, especially in the postsurgical patient. It most commonly results from fluid resuscitation after trauma or operative intervention without potassium supplementation. Another common cause is prolonged emesis seen in pyloric stenosis, which classically results in hyporchloremic hypokalemic metabolic alkalosis as potassium is excreted in exchange for sodium in the renal tubules. Vomiting and diarrhea from other reasons, as well as gastrointestinal losses from high output stomas or fistulae, can also lead to hypokalemia. Less commonly in the surgical patient, diuretic administration without potassium replacement may lead to hypokalemia. Diuretics induce sodium wasting and overall volume depletion, which may trigger aldosterone secretion and potentially worsen the hypokalemia. Intrinsic kidney disease may also result in potassium wasting and hypokalemia.

Signs and symptoms of hypokalemia are often subtle and may not be apparent unless there is an acute change in serum potassium concentration. Muscle weakness and ileus are the most commonly encountered and result from hyperpolarization of the muscle cells. Cardiac arrhythmias can occur, especially in patients taking digoxin. The U wave on electrocardiogram (ECG:Cardizem) is a classical sign of hypokalemia and is accompanied by low amplitude T waves. The urine potassium concentration may be useful in distinguishing among the causes of hypokalemia. In cases of hypokalemia where the urine concentration of potassium is less than 15 meq per L, appropriate conservation is being accomplished and thus losses are not due to renal dysfunction.

The purpose of this section is to review aspects that require emphasis for the treatment of children with physical disabilities.

The principles on which decision making are based for children with disabilities are the same as for typical children: autonomy, beneficence, justice, nonmaleficence, veracity, and fidelity (1). Parents and legal guardians are recognized legally as substitute decision makers for neurologically impaired children.

It is important for pediatricians and pediatric surgeons to discuss openly and forthrightly their approaches toward the treatment of severely cognitively impaired children. Agreement on principles is essential to provide best care. When conflicts arise, helpful mediation by a single member of a hospital’s Ethics Committee can be useful, without being cumbersome and time consuming. If true conflicts exist over specific cases, then formal consideration by the hospital Ethics Committee can help with resolution (2), although this is rarely required.