tailieunhanh - Critical Care Obstetrics part 58

Critical Care Obstetrics part 58 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 | 40 Hypovolemic and Cardiac Shock Scott Roberts Department of Obstetrics and Gynecology The University of Texas Southwestern Medical Center UTSMC at Dallas TX USA Introduction Hemorrhage is one of the leading causes of pregnancy-related mortality in the United States 100000 live births second only to embolism 100000 live births Table 1 . Almost 99 of maternal deaths occur in developing countries. Immediate postpartum hemorrhage PPH defined as excessive blood loss within 24 hours after childbirth is the single most important cause of maternal death worldwide accounting for almost half of all postpartum maternal deaths in developing countries 2 3 . I n the United States hemorrhage was the leading cause of death after stillbirth from abruptions and uterine rupture and accounted for 93 of deaths associated with ectopic pregnancies. Hemorrhage was also prominent as a cause of death in pregnancies ending in induced or spontaneous abortion 1 . These deaths are mediated through hypovolemic shock which is also responsible for a number of other serious non-fatal complications including acute renal failure acute respiratory distress syndrome ARDS and more rarely postpartum pituitary necrosis. The parturient undergoes several important physiologic adaptations during pregnancy to protect her from the bleeding expected at the time of delivery. Peripartum complications can occur quickly and since the uterus receives a blood flow of 450-650mL min quick decisive and coordinated action on the part of the practitioner and supporting staff can be life- saving 4 . Shock is perhaps best defined as reduced tissue oxygenation resulting from poor perfusion 5 . Low flow or unevenly distributed flow from hypovolemia and disproportionate vasoconstriction are major causes of inadequate tissue perfusion in the acutely ill patient with circulatory dysfunction or shock. In hemorrhagic shock the disparity is a result of blood loss that leads to both compensatory neurohormonal .