In a morbidly obese parturient whose vitals are unstable, obtaining IV access may be difficult and intraosseous access may be utilized to provide rapid resuscitation. The humerus is the recommended intraosseous site for obstetric resuscitation as it bypasses aortocaval compression and supports higher flowrates than the tibia. Intraosseous cannulation of the tibia has been found to be 30-40% more successful than proximal humeral insertions. 

A 32yo female with BMI 64 presented for repeat caesarean delivery. A CSE was placed to achieve a T4 anesthetic level. Her IV infiltrated prior to incision, BP dropped to 65/45, and there were no visible vein targets. 50mg ephedrine IM was given, she was placed in Trendelenburg, and left lateral table tilt was performed. An attempt to place an upper extremity US-guided IV was begun, and a search for IO landmarks was also begun. The greater tubercle of the humerus and the tibial tuberosity were not palpable. An IO needle was placed 3cm below the inferior margin of the patella and 2cm medial. Intraosseous crystalloid and vasopressors were given. FHR remained stable, an US guided IV was placed, and the case proceeded uneventfully.

Obtaining rapid access in the patient was difficult and required intraosseous cannulation. Blind intraosseous cannulation of the tibia established access quickly so resuscitation could begin while an ultrasound guided IV was placed. The proximal tibia can be a good option for intraosseous cannulation in the parturient because it is a presumably larger target than the proximal humerus, it is more likely to be successfully cannulated in a blind attempt, and the patient is insensate in the lower extremities from the epidural.