Ultrasound guided central venous access

Editor—Muhm in his editorial on ultrasound guided central venous access raises many valid points, prompted by recent guidelines from the National Institute for Clinical Excellence (NICE).¹,²

The evidence for this technology is stronger than for many other medical devices in routine use—for example, pulse oximetry or capnography in anaesthesia, which lack definitive controlled studies on outcome. I question whether is it ethical for practitioners with ultrasound skills and access to devices to revert to blind techniques for controlled trials. Such trials, if measured by numbers of complications, would require operators to persist blindly in difficult cases to the point of complication, rather than give up or use ultrasonography.

The cost of this technology is modest compared with many other medical technologies and the cost of complications. Minor (not to the patient) and major complications are very expensive in clinical, legal, and other costs, such as delayed surgery or discharge. The hidden costs of patients' discomfort, vein damage, thrombosis, and catheter related sepsis have never been measured but must surely relate to multiple punctures even if venous cannulation is eventually successful.

The editorial concludes that ultrasound localisation is a useful backup after failed blind cannulation for patients in whom catheterisation is likely to be difficult and when complications could be serious. Routine use of ultrasonography has the potential to avoid the first scenario, identify and sort out the second, and prevent the third. Currently it is impossible to identify all patients who are likely to have difficult procedures, and there are no patients in whom complications are not unpleasant and potentially serious.

For all the above reasons ultrasound localisation is likely to become standard practice in central venous access.