Detection of Hypotension During Cesarean Section With Continuous Noninvasive Arterial Pressure Device or Intermittent Oscillometric Arterial Pressure Measurement

Abstract

BMI < 25 kg/m 2 compared to 6.6% in women with BMI > 40 kg/m 2 . One option to reduce this rate is to tape the catheter after the patient is in the lateral position or in the position in which she is most likely to labor. Catheter position and anesthetic levels should be checked at least every 2 hours during labor to ensure correct position and adequate function.Labor analgesia in obese parturients requires a prelabor consultation to create an anesthetic plan, a check of equipment for appropriate size and function, presence of experienced staff and anesthesia providers, early initiation of neuraxial anesthesia, an appropriate method to locate landmarks, minimization of catheter movement, anticipation of difficulties with prolonged labor and likelihood of CD, evaluation of the neuraxial block every 2 hours, and frequent communication with the patient and all involved with care.T he increase in the use of spinal anesthesia for cesarean delivery has led to decreased maternal death and morbidity. However, hypotension during spinal anesthesia is a common side effect, with an incidence as high as 95%. Because of the potential harm of maternal hypotension to the fetus and the dependency of fetal oxygenation on maternal blood pressure (BP), the mother's BP should be monitored closely and hypotension treated immediately. Traditionally, BP is monitored with discontinuous oscillometric measurements [noninvasive blood pressure (NIBP)], but because it is not continuous, hypotensive episodes may be missed. A continuous NIBP device (CNAP Monitor 500) has shown agreement with invasive BP measurements. The CNAP system consists of a double finger cuff, a pressure monitor mounted on the forearm, and an oscillometric cuff mounted on the upper arm. The CNAP device is designed to keep the volume of blood in the finger arteries constant by altering pressure applied to the finger. The pressure applied during arterial pulsation is related to the arterial BP. This study was designed to investigate whether the CNAP device is more reliable in detecting episodes of hypotension than conventional NIBP measurement during cesarean delivery under spinal anesthesia.Patients received an intravenous preload with 500 mL starch solution, and spinal anesthesia was induced with hyperbaric bupivacaine of 10 to 12.5 mg. Eighty patients undergoing planned cesarean delivery were monitored with the CNAP device, and traditional NIBP was measured at 3-minute intervals until delivery. The CNAP finger cuff and the NIBP cuff were on the same arm. The CNAP monitor was calibrated before the first measurements and every 30 minutes thereafter during the comparison trial. Baseline NIBP was the first measurement obtained in the operating room. Baseline CNAP was averaged from the first 100 beats after the device was calibrated. Hypotension was defined as a decrease in systolic BP by >20% or systolic BP < 100 mm Hg. Hypotension was treated with a standardized protocol with Akrinor and hydroxyethyl starch, if necessary. The mean BP for the highest and lowest CNAP per 3-mi...