الفهرس 
Anatomical And Physiological Changes During PregnancyOnly 14 pages are availabe for public view
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Abstract
UPDATE IN ANAESTHESIA FOR NORMAL PREGNANT PATIENT UNDERGOING NONOBSTETRIC SURGERY
Pregnant women undergoing surgery require special attention in their anesthetic management if injury of the fetus to be avoided. The basic objectives in the anesthetic management of pregnant patients are maternal safety, avoidance of teratogenic drugs, avoidance of intrauterine fetal asphyxia, and prevention of preterm labor.
Many of the physiological changes of pregnancy are due to hormonal influence and may occur early in pregnancy. Significant changes in minute ventilation, functional residual capacity and anesthetic requirements occur during the second and third trimesters and may predispose the mother to an anesthetic overdose. Similarly, the hypotensive syndrome associated with the supine position begins to manifest itself early in the third trimester and may lead to decrease in cardiac output, blood pressure and uterine blood flow.
Most commonly used anesthetic and premedicant drugs are teratogenic in some animal species. However several studies conclude that no adverse effects of anesthetic drugs on reproductive outcome could be accepted on the basis of retrospective enquiries, Except for some debate about the use of benzodiazepines and nitrous oxide during pregnancy, so that results can be seriously questioned.
Some reports suggested that anesthesia and surgery during pregnancy are associated with the onset of preterm labor. No one agent or technique has been associated with higher incidence of premature delivery. However the halogenated anesthetics decrease uterine contractility if uterine manipulation is anticipated, the use of these agents would theoretically be more likely to minimize the possibility of preterm labor.
On the bases of these considerations, the following practice for pregnant patients undergoing surgery was recommended:
Elective surgery should be deferred until at least six weeks after delivery, by which time the physiologic changes of pregnancy should have returned to near normal pre-pregnancy values.
Urgent surgery (that is operations that are essential but can be delayed without increasing the risk of permanent disability) should be deferred until the second or third trimester. Inspite no anesthetic drug, inhaled anesthetic agent or local anesthetic have been proven to be teratogenic in humans, however it would be prudent to minimize or eliminate fetal exposure to drugs during the first trimester.
If an emergency operation is necessary, it’s ideally performed under regional block if the contemplated surgery and maternal condition permit.
In general physicians agree that only emergency surgery should be performed during pregnancy. The possibility of pregnancy should be considered in all female surgical patients of reproductive age, so that the urgency of the proposed operation can be rationally evaluated.