Probit analysis, combined spinal and epidural and the duration of spinal block in the obese patient.

摘要

There have been many published studies over the years comparing the effects on spinal block using different intrathecal agents. The classic study design has been the randomised controlled trial and clinical endpoints have been principally height of sensory block and degree of motor block. Well worked out protocols have been developed1. However, the outcomes of these studies have been compromised by the wide range of block heights that result from an intrathecal injection and the confinement to a single, usually large, one-shot dose to guarantee satisfactory anaesthesia. Such a wide range of values affects the standard deviation of the main study outcomes such as sensory block height, and causes a lack of sensitivity when performing statistical comparisons.