Hypotension Following an Epidural
Presentation:
A.W. was a 26 year old gravida 2, para 1 whose labor was being augmented by Pitocin®. A.W. was 3 centimeters dilated, 60% effaced, and requested her epidural at this time. Her baseline blood pressures were within a normal range (ranging from 110s-130s/70-80s). Upon requesting the epidural, the patient was bolused with one liter of LR (lactated ringers) as per protocol to prevent hypotension. In addition, she read and signed the consent form recognizing that hypotension is the most commonly seen adverse effect of an epidural. The effect of local anesthetics on the large spinal nerves is to decrease the tone of the muscles, including those in the walls of the blood vessels. Blood then pools in the lower extremities and there is a decrease in the return of the blood to the right side of the heart resulting in decreased cardiac output. A.W. positioned herself correctly, was administered the epidural consisting of bupivacaine and fentanyl, and was then connected to the continuous epidural infusion. After taping down the catheter, A.W. was instructed to promptly lie down (slightly tilted towards one side). A supine position is contraindicated due to the gravid uterus compressing the abdominal aorta and inferior vena cava resulting in decreased uterine profusion. Once the patient was lying down, the nurse began the epidural recovery—taking five blood pressure readings in three minute intervals. During this time, the nurse monitored the patient’s blood pressure and response to pain, and the fetal heart tracing.
A.W.’s first 3 blood pressures were the following: 122/76, 111/69, 89/58. It was apparent that A.W. was experiencing hypotension related to the epidural. Systolic pressure below 100 mmHg or a 20-30% fall in systolic pressure is considered hypotension. At the time of the third blood pressure reading, the fetal heart rate showed a deceleration (decreasing from the baseline of 130 to 90s). While the nurse instructed A.W. to roll to her other side, she called the anesthesiologist to get an order for ephedrine. At this time the patient stated that she was dizzy and “felt funny”. Ten milligrams of ephedrine was drawn up and inserted intravenously. Ephedrine increased A.W.’s blood pressure by increasing the venous return, increasing the heart rate, and increasing cardiac output. In addition, ephedrine restored the end diastolic flow in the uterine artery and therefore, increased the uterine profusion. The clinical effects of ephedrine are seen almost immediately. A.W.’s next two blood pressures read 100/70 and 115/81. The fetal heart rate increased to baseline within one minute and the baby no longer showed any signs of distress. A.W. felt remarkably better in the next five minutes and hours later she delivered a beautiful, healthy baby girl.
Case created by Andrea Weiss, 2010.