Measurement of residual volume in spinal needles after spinal anesthesia

Introduction Spinal anesthesia involves the administration of a dose of local anesthesia into the intrathecal space of the lumbar spine, using spinal needles with varying characteristics and design. When completing the administration of spinal anesthesia, you may check the volume of fluid remaining inside the spinal needle. Objective To measure and compare the volume of residual fluid following the administration of spinal anesthesia using three different brands of 27 gauge spinal needles. Methods This is an observational analytical cross-section trial for which tree types of 27 gauge commercial needles were selected: BD Whitacre pencil point, Spinocan Quincke sharp point, and Disposable spinal needle. Following the administration of spinal anesthesia, the same operator, without detaching the syringe from the needle, deposited the residual volume into a collection tube so that a second operator quantifies the volume using a precision micropipette. Results The residual volume obtained from the 27G spinal needles showed a statistically significant difference in favor of the BD Whitacre needles ( P < 0.01), compared against Spinocan Quincke and Disposable spinal needle. Conclusions The BD Whitacre pencil point proved to lodge less residual volume following spinal anesthesia. No clinical implications can be made from this finding and new studies are required to ratify these results.