may be a contributing factor to the result in this study? Similarly, the type of analgesia used for laparoscopic surgery could also be open to review, with the use of epidurals, again extrapolated from open surgery, being shown to prolong the hospital length of stay in this group. 3 Could this also have a bearing on the results, although in this case, thoracic epidural analgesia (TEA) was used in both arms of this section of the trial? As with many good studies, this raises more questions than it directly answers. Among these questions must be the appropriateness of extrapolating the results of studies in anaesthesia for open colorectal surgery to laparoscopic colorectal surgery without direct evidence of a benefit in the later group.

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Editor-We read with interest the recent article by Schummer and colleagues 1 regarding the use of pre-procedure ultrasound (US) to facilitate central venous (CV) catheterisation. In an observational study investigating 606 procedures, the authors demonstrate that pre-procedure US is superior to landmark methods. The investigators conclude that pre-procedure US offers an alternative to real-time US and are to be congratulated for adding further support to US as an instrument to further patient safety and improve outcomes.We would, however, like to raise the following issues. Although some risk factors for difficult insertion have been recorded, we feel the list is not comprehensive. One of the main complications recorded was the incidence of severe haematoma associated with line insertion. CV cannulation can be safely carried out in the presence of coagulopathy, although an increased risk of haematoma formation in the presence of coagulation deficit has been described. 2 We note that the highest incidence of haematoma formation (2.5%) occurred in the landmark group containing the highest number of cardiac patients. We might speculate that cardiac medications, such as antiplatelet drugs, may be implicated. Based on these factors and the importance of haematoma formation as a measured outcome, we are surprised that normal coagulation and platelet count/ function were not listed as specific inclusion criteria.We would also like to draw attention to the issues raised regarding availability and cost. The authors state 'most practitioners do not have real-time US as an option'. We would suggest that US hardware is widely accessible. A survey of 294 UK anaesthetic departments revealed that 172 of 199 respondents (86%) had ultrasound readily available. 3 The authors also suggest a problem with the 'perceived expense' of real-time US and a fear of 'large investments' in hardware. This is presented as a reason for investigating the use of pre-procedure US. The US machine used in the study utilises an 18 -6 MHz linear probe, which is likely to be suitable for real-time cannulation. As US hardware would be required for both pre-procedure and realtime techniques, we fail to recognise pre-procedure US as a significantly less expensive option. Although pre-procedure US may reduce the costs of disposables associated with CV cannulation (such as sterile probe covers and sterile gel) these items cost very little per procedure. 4 5 The authors identify that 'unnecessary time expenditure' is a complaint against realtime US. Their citation regarding this consists of an opinion survey of members of the Society of Cardiovascular Anesthesiologists. The survey demonstrates that only 113 of 1494 respondents (8.5%) were concerned about a possible time delay when using US. 6 No evidence of actual delay with realtime US is provided. Furthermore, a comprehensive technology appraisal conducted by the National Institute of Health and Care Excellence has concluded that US guided cannulation is a cost effective option and is recommended for electi...

A 42-year-old woman presented to an eye clinic with a 2-week history of diplopia. Examination revealed signs of a right sixth nerve palsy. A computed tomography (CT) brain scan was normal. Six weeks later she presented during the acute medical take with increasing diplopia, a drooping right eyelid and unsteadiness. Direct questioning revealed that the drooping became progressively worse throughout the day. She had no relevant past medical history or any regular medication. Examination revealed a partial right ptosis and signs of right third, fourth and sixth nerve palsy. Diplopia on binocular vision resolved on patch testing; neurological examination was otherwise unremarkable, with no evidence of limb weakness. A magnetic resonance imaging scan of the brain and CSF examination were unremarkable. Ocular myasthenia was suspected, anti-acetylcholine receptor antibody test was requested, and a Tensilon test was performed with full resuscitation equipment available. Following the administration of the test dose (2 mg) of intravenous edrophonium (Tensilon) a visible improvement in the right ptosis was observed. Subsequent administration of a further 8 mg edrophonium yielded more marked improvement, with complete correction of the right ptosis (Figure 1) and a subjective decrease in diplopia on right gaze. A diagnosis of unilateral ocular myasthenia gravis was made on the basis of the clinical picture and the positive Tensilon test. A neurological opinion was sought and the patient commenced on pyridostigmine 60 mg four times a day. Further investigations included a CT scan of the thorax which revealed a 2 cm retrosternal mass, compatible with thymic hyperplasia. Five weeks after the positive Tensilon test, a report of strongly positive anti-acetylcholine receptor antibodies (anti-acetylcholine receptor antibodies >8 nmol/litre, normal range 0–0.5 nmol/litre) was received. The diplopia continues to improve and the patient has regular follow up.

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