Connection of capnography sampling tube to an intravenous cannula

Abstract

There are many connectors on a variety of devices used with a single patient. It is not surprising therefore that misconnections are made either inadvertently or due to confusion because of the large number of potential connections. During a routine anaesthetic the Luer lock sidestream capnograph sampling tube was inadvertently connected to an intravenous cannula. We noticed that blood had contaminated the sampling tube, which led us to find the misconnection and immediately rectify it. Fortunately, the side stream capnograph sampling tube aspirates gas and as a result no injury occurred to the patient, although blood from the patient would eventually have entered the sampling port of the capnograph. A much more serious event would have occurred if the gases leaving the capnograph and returning to the patient circuit had been inadvertently connected to an intravascular cannula leading to air entering directly into an artery or vein. The original purpose of the Luer fitting was to connect a hypodermic needle to a syringe. However, the connector has been so successful that it is now used in a wide range of medical devices, raising the possibility of accidental cross connection between devices [1]. Mistaken connection between a scavenging tube and a facemask has been previously reported [2], as has a misconnection between the common gas outlet and the scavenging port [3]. The European Union has a regulatory framework for market access, international trade relations and regulatory convergence, and industry competitiveness for market devices. There are three European Directives which regulate marketing and putting into service of medical devices. These are the Active Implantable Medical Devices Directive (AIMDD), the Medical Devices Directive (MDD) and the In-Vitro Diagnostic Directive (IVDD). Since 1998 the Medical Devices Directive [4] has provided for a harmonised regulatory environment for all medical devices sold within the European Economic Area. All products which fall within the scope of the Directive must meet certain essential safety and administrative requirements and are CE marked to show that they comply. The European Directive for Medical Devices requires the manufacturer to design and construct devices in accordance with safety principles that ‘eliminate or reduce any risk to the patient as far as possible. If the device is intended for use in combination with other devices or equipment, the whole combination, including the connector system must be safe’. A task force (CEN/BT/TF 123) has been set up to produce non-interchangeable connectors for enteral feeding, respiratory connectors, NIBP hoses, urinary catheters, endoscopes and tourniquets [5]. Fundamentally, the problem results from the application of a single connector design to a number of incompatible applications and a global solution that addresses all aspects of the problem is urgently required. Hopefully, the European Task Force will provide a satisfactory solution as a matter of some urgency.