Light touch - How do you do it? An observational study of practice.
Abstract Number: 49
Abstract Type: Original Research
Introduction: Assessment of sensory level using light touch is essential prior to the commencement of caesarean section under regional blockade. 1 Different methods exist to measure light touch but these have not been evaluated for reproducibility.2
Methods: 22 anaesthetist were recruited and asked if they routinely checked light touch prior to commencement of surgery. They were then invited to demonstrate this on a set of scales with the measurements concealed. This was recorded and then analysed to determine the maximum pressure applied by each method of assessing light touch.
Results: Of the 22 participants 50% did routinely check light touch prior to commencement of surgery, 4 using gauze, 1 cotton wool, 4 used their or the mother's finger, 1 a standardised 10g filament and 1 ethyl chloride. Graph 1 shows the results of pressure applied using different modalities. One errant measurement, 1.2N using the finger, was removed from the analysis. The mean pressure applied using the finger was 0.11N, SD 0.09N. Using cotton wool the mean pressure applied was 0.07N, SD of 0.07N and using gauze mean pressure applied was 0.05N, SD 0.04N.
Discussion: In this group of anaesthetists sensory level assessment to light touch is still not always tested routinely, and when it is tested it is performed by varying modalities. Marked differences between operators and modalities existed. Whilst not statistically significant our results suggest that the modalities may not deliver comparable pressures. We intend to investigate this further.
1. Russell I. At caesarean section under regional anaesthesia it is essential to test sensory block with light touch before allowing surgery to start Int J Obstet Anaesth 2006;15(4):294-297
2. Kocarev M, Watkins E, McLurie H, et al. Sensory testing of spinal anaesthesia for caesarean section: differential block and variability Int J Obstet Anaesth 2010;19(3):261-265