The Effect of Body Mass Index, Intra-abdominal Pressure, Abdominal Girth and Waist Circumference on Sensory Block Level After Single-shot Spinal Anesthesia for Cesarean Section

However, in pregnant patients, venous engorgement is prominent in the supine but not the lateral position, which suggests direct compression of the inferior vena cava by the gravid uterus. Second, an increase in intraabdominal pressure may affect the retroperitoneal area and may cause inward movement of soft tissue in the intervertebral foramina. Recent magnetic resonance imaging studies in pregnant patients, although without intraabdominal pressure measurements, suggested the latter because they showed limited contact of engorged veins along the dural sac which may therefore not be responsible for compression of the dura.

If elevated intraabdominal pressure contributes to high anesthetic spread during pregnancy, one would expect a relationship between intraabdominal pressure and maximum sensory block level.