What are the potential consequences of epidural anesthesia in the patient with preeclampsia?
Epidural anesthesia can be beneficial for the patient with preeclampsia. Decreasing or eliminating the sensation of pain will reduce hyperventilation, decrease cate-cholamine release, decrease anxiety, and increase uteropla-cental blood flow. A regional anesthetic will also obviate the need for a general anesthetic with its inherent risk of aspiration. However, prior to administering the epidural catheter the blood pressure must be controlled, the intravas-cular volume replete, and the coagulation profile normal.
The diastolic blood pressure should be less than 110 mmHg before beginning a neuraxial anesthetic. Frequent blood pressure measurements will be needed during the anesthetic. An arterial line may be necessary if the blood pressure is labile.
The parturient with hypertensive disease is usually fluid-depleted and unless the fluid level is restored toward normal, the patient will be subject to profound drops in blood pressure. Urine output is monitored to guide fluid administration. If urine output is diminished, a fluid chal-lenge of 500–1000 mL of an isotonic crystalloid should be given depending on the clinical scenario. If urine output does not increase, central venous pressure monitoring should be instituted. Severe preeclampsia may require pulmonary artery pressure rather than central venous pres-sure monitoring, since these patients may have left ventric-ular dysfunction and congestive heart failure.
Fluid replacement should be with either an isotonic crystalloid or colloid solution. Dextrose in water should not be administered because of the risk for water intoxica-tion, especially in the presence of oxytocin. There is also the risk for neonatal hypoglycemia.
Platelet consumption is a component of preeclampsia that can lead to factor consumption and DIC. Therefore, a platelet count and coagulation profile must be checked prior to administering the anesthetic. Generally, the platelet count decreases before other indices of coagulation are pro-longed. Therefore, it is acceptable to first check the platelet count and, if it is less than 100,000 mm−3, to then check the prothrombin time (PT), partial thromboplastin time (PTT), and fibrinogen. Since preeclampsia is a dynamic process, the coagulation parameters should be checked as close to the time of administering the block as possible.