tailieunhanh - Critical Care Obstetrics part 10

Critical Care Obstetrics part 10 provides expert clinical guidance throughout on how you can maximize the chances of your patient and her baby surviving trauma. In this stimulating text, internationally recognized experts guide you through the most challenging situations you as an obstetrician are likely to face, enabling you to skillfully:Recognize conditions early-on which might prove life threatening, Implement immediate life-saving treatments in emergency situations, Maximize the survival prospects of both the mother and her fetus | Fluid and Electrolyte Balance The severity of the hypokalemia is dependent upon the pretreatment concentration of serum K . The effect is more pronounced when the pretreatment K concentration is high and the effect is reduced in patients with pre-existing hypokalemia. Nevertheless patients with pre-existing hypokalemia may be at greater risk of developing the complications of hypokalemia 168 . Since the hypokalemia associated with intravenous administration of p2-agonists represents an intracellular shift with unchanged total body K and hypokalemic side effects are uncommon serum K of L generally does not require K replacement. At levels L serious cardiac arrhythmias have been reported with p2-agonist tocolysis and replacement of K is recommended 166 . Bartter s syndrome is an autosomal recessive disorder characterized by hypokalemia hyperaldosteronism sodium wasting normal blood pressure hypochloremic alkalosis and hyperplasia of the juxtaglomerular apparatus 169 . Increasing numbers of cases are being reported in the literature 170 171 . Hypokalemia is responsible for most of the symptoms of Bartter s syndrome and therapy is directed toward increasing the K concentration with supplements and K -sparing diuretics. Over one-third of patients with Bartter s syndrome also suffer magnesium wasting and increased magnesium supplementation may also be required for treatment. Pica in pregnancy is more common than realized and often goes unrecognized 172 . Geophagia with ingestion of clay during pregnancy is a common practice in some parts of the US and around the world. The clay binds K in the intestine and if enough is ingested it can cause hypokalemic myopathy 173 . Questioning about pica should be included in the history for patients who present with hypokalemia and symptoms as noted below. Clinical p resentation Muscle weakness hypotonia and mental status changes may occur when the serum K is below L. ECG changes occur in 50 of patients with .