At caesarean section under regional anaesthesia, it is essential to test sensory block with light touch before allowing surgery to start

Assessment of block height for satisfactory spinal anaesthesia for caesarean section

“…In contrast to strong opinions to the contrary [3,4,12], our study findings suggest that height of block assessments to cold may be reliable in most cases and appear much more likely to avoid assessing an adequate block as one that is unsatisfactory for surgery to proceed. Whilst some may argue that 'most' isn't enough, Russell's own definition of an adequate block height to touch for caesarean section to start is when T6 is 'either blocked to touch, or expected to be blocked to touch before surgery had reached the peritoneal cavity' [3].…”

“…While situations will always exist in which a general anaesthetic is the most prudent management, premature or unnecessary abandonment of an adequate regional anaesthetic block, based on a single method of assessment, may result in the mother's being unable to participate in the birth experience, and risks maternal morbidity and even mortality. The inherent inaccuracy of assessment of block height has been well documented and considerable variation may exist between individual anaesthetists [10][11][12][13][14]. The critical importance of communication and the way anaesthetists question patients about their block have been emphasised [12].…”

“…The inherent inaccuracy of assessment of block height has been well documented and considerable variation may exist between individual anaesthetists [10][11][12][13][14]. The critical importance of communication and the way anaesthetists question patients about their block have been emphasised [12].…”

“…In contrast, we have not used an 'expectation' component in the assessment but the actual block level achieved before commencing surgery. In addition, where other researchers have assessed 'normal touch' against a reference point before surgery, they report that a number of patients required intervention despite a block height to normal touch above T6 [12]. While a more standardised assessment of block has been recommended [1,4,18], the subjective influences that inevitably occur when assessing block height will remain.…”

“…The use of an ice cube to assess touch and not a separate standardised tool such as the Neurotip may be criticised, but we find that our use of ice, to assess the first sensation of touch, cold and icy cold, is an easy and inexpensive way for most patients to communicate to the anaesthetist the height of block, and reflects current practice within our institution. Our height of block assessment using the first sensation of touch rather than normal touch against a reference point may be questioned, but the first sensation of light touch is reported to be 'the best predictor of the likely efficacy of a spinal or epidural block' [12]. Interestingly, there seems to be 'a close association between the levels of block to touch assessed by the ethyl chloride spray and the Neurotip' and 'in normal clinical practice ethyl chloride spray touch sensation can be considered equivalent to Neurotip touch in predicting the likely adequacy of spinal anaesthesia' [3].…”