Minimum effective local anaesthetic dose for spinal anaesthesia.

Editor—In their response 1 to my criticisms 2 of their paper 3 Sell and colleagues accept some of my points, and refute others. On most of the latter we will simply have to agree to differ, but, not surprisingly , I cannot accept their quoting my own review 4 in support of their belief that the solutions which they used were isobaric! Their quote from the article ('Given the normal variation [of CSF], it is necessary that solutions that are to be predictably hypobaric or hyperbaric in all patients have baricities below 0.9990 or above 1.0010 respectively') is correct, but it is taken out of context, and ignores the key relevance of the words 'given the variability.. .' and 'predictably', to say nothing of the arguments that follow in the rest of that paragraph. These lead to the specific conclusion that the word 'plain' is a more appropriate descriptor so I would ask them to consider the paragraph in full, not just a selective quote.