Conus medullaris injury following both tetracaine and lidocaine spinal anesthesia.

Multiple reports of cauda equina syndrome and transient radicular nerve root irritation have suggested that lidocaine spinal anesthesia may be responsible. In this case report, a patient with a preexisting diabetic neuropathy received a partial block following a tetracaine spinal, which was followed by a lidocaine spinal. Following block resolution, a new conus medullaris syndrome was diagnosed. Because of the close proximity of the cauda equina and the conus medullaris, differentiation between these syndromes can be difficult. The preexisting diabetic neuropathy may have predisposed this patient to neurologic injury. The choice of a different local anesthetic drug with less neurotoxic potential such as bupivacaine may have prevented this injury.

Evaluation of an intensive sampling and analysis method for carbon monoxide.

This paper describes a portable, low-cost whole air sampler capable of collecting 12 1-L samples in tedlar bags and using a single "D" cell for power. The results are presented from two tests of an intensive sampling and analysis method for measuring ambient carbon monoxide (CO) concentrations in urban areas using this sampler. The method is evaluated in comparison with an approved continuous CO analyzer, in intercomparisons of the results of re-analysis of the samples, and by examination of the results from co-located samplers. The precision of the analytical method was found to be +/-0.30 ppmv. The precision of the sampling method was found to be +/-0.73 ppmv and therefore is the limiting factor in the method's overall precision. These values are sufficient to verify attainment of National Ambient Air Quality Standards (NAAQS) levels in urban areas. Improvements in the sampler and analytical procedure are discussed.