The effect of obesity on neuraxial technique difficulty in pregnant patients: a prospective, observational study.

Background: Practitioners often presuppose that obesity will increase neuraxial technique difficulty in pregnant patients, but few investigators have systematically examined this population for risk factors associated with difficult epidural or spinal needle placement. We designed this study to prospectively identify factors that predict neuraxial technique difficulty in pregnant patients.

Methods: Using a prospective, observational format, pregnant patients were examined for multiple potential risk factors for neuraxial technique difficulty, including current body mass index, ability to palpate spinous processes, maximum back flexion, scoliosis, and experience of the practitioner.

Factors predicting short-term outcome of nerve blocks in the management of chronic pain.

In order to identify those chronic pain patients unlikely to improve from nerve blocks, preadmission questionnaires of 337 patients were studied and various pre-existing factors were analyzed against short term treatment results. Factors associated with significant reductions in treatment success (P less than 0.05) included: being injured at work, being out of work because of pain, receiving financial compensation, involvement in legal action, previous surgery for pain, long duration of pain, high pain severity ratings, frequent analgesic use and use of tranquilizers.