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Critical Care Obstetrics part 40

Critical Care Obstetrics part 40 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 | Acute Renal Failure ATN may occur in cases of rhabdomyolysis or massive hemolysis. More commonly in pregnancy however ATN is ischemic in nature as a result of a hemodynamic insult with hypotension and impaired renal perfusion. This is commonly due to a hemorrhage during pregnancy which may be the result of either placental abruption or a postpartum hemorrhage which complicates approximately 1 and 4-6 of pregnancies respectively 16 . In those patients with pre-eclampsia who develop renal failure ATN appears to be the underlying renal lesion. Clinically it may be difficult to distinguish between severe prerenal azotemia and ATN although urinary indices and urinalysis may be helpful Table 28.2 . Urinalysis typically reveals muddy brown granular casts and renal tubular epithelial cells. In light of impaired renal tubular function laboratory evaluation reveals a high urinary sodium excretion as well as urine that is neither concentrated nor dilute. Acute tubular necrosis may be either oliguric urine output 400mL day or non-oliguric 400mL day depending on the mechanism of injury and the severity. Treatment of ATN is supportive and necessitates optimization of hemodynamics avoidance of potential nephrotoxin exposure nutritional support with careful monitoring of fluids and electrolytes and occasionally dialysis. Renal function typically recovers in 7-14 days with appropriate treatment. Urinary obstruction Although urinary obstruction is a relatively uncommon cause of ARF in pregnancy it is readily reversible and therefore must be considered in the differential. Obstruction may occur at any level of the urinary tract due to a wide variety of causes many of which are not unique to pregnancy Table 28.6 . Additionally gravidas with an abnormally configured or overdistended uterus such as those with uterine leiomyomata polyhydramnios or multiple gestations may be particularly susceptible. Ureteral compression by the gravid uterus with resultant ARF and hypertension has been .