الفهرس 
الملخص العربى
hemorrhageOnly 14 pages are availabe for public view
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Abstract
The challenges presented by a parturient requiring anesthesia or analgesia or both, make the role of the obstetric anesthesiologist both challenging and rewarding. Those providing anesthetic services to the labor and delivery suite must be familiar with the unique physiology of the parturient and the effects of numerous drugs and techniques on the parturient and fetus.
Continuous improvements in drugs and techniques have led to a significant decrease in anesthetic related deaths in the delivery suite. The maternal mortality rate in the United States is estimated at 7.5 per 100,000 live births), however, many suggest that this statistic is misleading because of underreporting of maternal deaths). A recent retrospective analysis of maternal mortality during hospital admission suggested that anesthesia-related complications accounted for 5.2% of maternal deaths.
Anesthesia in pregnancy has become safer over the years, although anesthetists may still be involved in obstetric deaths due to emergencies mostly hemorrhagic emergencies.
The Anesthetist has to be prepared for unpredictable events in obstetrics, which often require urgent or emergency management. These events involve rapid clinical deterioration of either the mother, the fetus or both, which can lead to morbidity or mortality.
Clear guidelines for their management are important, especially in areas of the hospital such as the accident and emergency department where there may be no immediate back-up from the obstetric unit.
Management of obstetric emergencies is a critical part of anesthesia practice. Difficulty encountered at these emergencies ,potentially resulting in significant mortality and morbidity. Management of unpredictable obstetric emergencies leading to rapid deterioration of mother, fetus or both requires the skills of an obstetric anesthetist.
Among all these emergencies the following was covered in the review:
Hemorrhage
Severe obstetric hemorrhage may be defined as acute pre-partum blood loss greater than 1500 ml. Antenatal hemorrhage can be caused by separation of a placenta previa, placental abruption or uterine rupture, ectopic pregnancy. Postpartum hemorrhage may arise from the placental bed, particularly if there is retained tissue or uterine atony , or from vaginal or cervical lesions. Primary postpartum hemorrhage occurs within 24 hours of delivery. Secondary postpartum hemorrhage occurs later, typically after 5–7 days, and is usually associated with infection.
Management involves resuscitation of the mother, with provision of anesthesia for obstetric intervention to stop the bleeding, and resuscitation of the fetus. The ABC approach to management is used. Administer high flow oxygen, establish large-bore intravenous access and give 2000 ml of intravenous crystalloid or colloid. If further fluid resuscitation is required at this stage, consider blood and blood products.
The principles involve simultaneous resuscitation of the patient with provision of anesthesia for obstetric intervention to stop the bleeding. Prompt recognition and rapid response is necessary. This is facilitated by easy access to necessary equipment and drugs, for example by the provision of a dedicated ‘major obstetric hemorrhage trolley’ containing, for example, cannulae , fluids, blood sampling bottles and monitoring equipment. Multidisciplinary protocols which are familiar to all staff and are practiced regularly as simulated drills’ are important. They should include a predetermined staff call-out with assistance from senior staff (anesthetic, obstetric, midwifery and hematological).
Fetal Resuscitation
Fetal well-being can be monitored by assessment of the fetal heart rate and analysis of scalp capillary blood samples from the fetus (accessible once the membranes are ruptured). A normal fetal heart rate is 120–160 b\pm with good variability, i.e. change in baseline rate of 6–10 b\pm two to six times every minute. This is a sensitive indicator to exclude fetal asphyxia. Recognized abnormal patterns of fetal heart rate, such as late or variable decelerations, or loss of variability, are associated with poor pre-natal outcome, but the predictive value is poor.
A capillary sample may be helpful if the trace does not improve following fetal resuscitation. A pH of 7.0 correlates with a significantly increased risk of pre-natal death or infant morbidity.
Resuscitation of the fetus where asphyxia is suspected involves the identification and correction of reversible factors. These include:
(1) Alteration of maternal position from supine to lateral when aorto-caval compression has occurred leading to uterine hypo-perfusion;
(2) Maternal administration of a high inspired concentration of oxygen to reverse any hypoxemia.
(3) Tocolysis if hyper stimulation of uterine contractions is causing inadequate uterine blood flow.
(4) Intravenous fluids and ephedrine where regional anesthesia has caused hypotension by vasodilatation;
(5) Restoration of blood volume where maternal bleeding has occurred;
(6) rapid delivery of the fetus, either vaginally or by emergency Caesarean section.
Maternal collapse and Resuscitation
Maternal cardiac arrest is rare and may represent the endpoint of a number of different maternal emergencies. Delivery suite staff is unfamiliar with cardiac arrest, and therefore the obstetric anesthetist usually leads the resuscitation process.
Regardless of the presumed cause of the arrest, resuscitation should follow the standard ABC approach. However, there are two extra considerations: the increased risk of aspiration and the contents of the uterus.
Resuscitation should then be continued along ALS guidelines, using DC defibrillation and/or epinephrine. If resuscitation is unsuccessful despite these maneuvers, the baby should be delivered after 5 minutes. To achieve this goal it is essential that from the moment cardiac arrest is diagnosed, a surgeon is preparing to carry out the pre-mortem caesarean section.
Management OF Blood Transfusion
The need for transfusion in the obstetric population is not uncommon, but there is often reluctance on the part of anesthesiologists to employ it.
importance, benefits, disadvantages, complications of blood transfusions in obstetric emergencies were reviewed.