Case Report: A novel technique for the placement of spinal subarachnoid anesthesia in the obese parturient
Abstract Number: 101
Abstract Type: Case Report/Case Series
Introduction: Placement of spinal anesthesia is a common procedure. It is often the anesthetic of choice in the parturient undergoing a cesarean section. This can prove to be challenging in the obese parturient. We describe a novel technique for successful placement of spinal anesthesia in an obese parturient undergoing a cesarean section.
Case Presentation: A 27 year old female, 38 weeks pregnant (G2:P1), was scheduled to undergo an elective cesarean section. The patient was 5 feet 4 inches tall and had a pre-pregnancy weight of 290 lbs and now weighed 305 lbs. Her indication for cesarean section was that she had one in the past. Given her size and the need to easily penetrate the tissues in a linear path we decided to use a longer 4.69in 25g spinal in combination with a 20g 3.5in spinal needle acting as the introducer. After a skin wheel was made with local anesthetic, the 20g whitecar spinal needle without the stylet was pierced into the skin wheel. Then the longer 4.69in 25g spinal needle was inserted into the 20g 3.5in spinal needle (introducer) and advanced until the hubs of both spinal needles were touching. Both spinal needles were then advanced together until a pop was felt. At that point the stylet of the longer 25g spinal needle was withdrawn and cerebrospinal fluid (CSF) was appreciated as it was slowly dripping. A syringe containing local anesthetic and low dose fentanyl was attached and injected after 1cc of aspiration of CSF. The rest of the cesarean section was uneventful.
Discussion: Successful placement of spinal anesthesia can be challenging in the obese parturient because the increased fat makes it difficult to elucidate the anatomy. More importantly the increased fat creates more resistance causing the tip of the spinal needle to deviate from the intended linear path. The standard, 3.50in 25g, whitacar spinal needles will not reach the subararchnid space due to an increased distance created by the excess fat. However the longer, 4.69in 25g, whitacar spinal needles are very flimsy making it difficult to advance in a linear path, especially through a standard 1.25in 20g introducer. Whereas the 20g 3.50in spinal needle acts as a longer introducer and provides strength thus mitigating the flimsiness of the longer 25g spinal needle. We believe the ease of penetration of the spinal needle in a linear path increases the chance for a successful subarachnoid block in obese parturient.