Central venous catheterisation - clinical studies on mechanical complications in the ultrasound-guided era

Abstract: Central venous catheterisation is one of the most common invasive procedures performed on patients in secondary care. Unfortunately the catheterisation procedure is associated with mechanical complications that both can be life-threatening and may force postponement of life-saving treatments such as surgery and chemotherapy. The use of real-time ultrasound guidance increases success rates and reduces the numbers of mechanical complications ¬– but major mechanical complications still occur. The general aim of this thesis was to explore various aspects of ultrasound-guided central venous catheterisation and associated mechanical complications in order to enable future quality improvements of the procedure.Papers I and II investigate the incidence of mechanical complications within 24 hours after central venous catheterisation and analyse possible associated risk factors. In total, 12 667 central venous catheter insertions in 8 586 patients were included. We found that in hospitals where real-time ultrasound guidance is standard of care for central venous access, the incidence of major mechanical complications was only 0.4%. We also identified patient BMI <20 kg/m2, male operator gender, limited operator experience and more than one skin puncture as independent risk factors for major mechanical complications. In addition, subclavian vein catheterisation was an independent risk factor for pneumothorax compared to internal jugular vein catheterisation. Paper III evaluates the use of a micro-convex probe and the right supraclavicular fossa ultrasound view for aiding guidewire positioning to avoid catheter misplacements in right infraclavicular subclavian vein catheterisation. We prospectively included 103 patients and showed that with the ultrasound method described, 14 of the 15 initially misplaced guidewires were detected and 12 of them were successfully adjusted to a correct position, which in turn helped avoid 12 catheter misplacements at the time of insertion. Paper IV estimates the minimal guidewire length required to avoid guidewire retraction, thereby maintaining a guidewire tip position in the lower segment of the superior vena cava throughout an ultrasound-guided infraclavicular catheter placement in the right subclavian vein. Based on vessel measurements in 100 patients, we concluded that the majority of the assessed 15–16 cm central venous catheter kits contain guidewires that are too short for right subclavian vein catheterisation, i.e., guidewire retraction is needed prior to catheter insertion. Paper V examines the effect of an implementation package on the documentation of central venous catheter insertions. We found that introduction of an updated central venous catheter insertion form, delegated information responsibility of the new local directions for central venous catheter placement, and follow-up of all registered insertion forms during a limited period of time reduced the porportion of missing data with 55%.The general conclusion of this thesis is that there are possibilities for further quality improvements of central venous catheterisation also in the ultrasound-guided era and that the combination of appropriate recording of central venous catheter insertions, possibilities to track patient outcomes, and clinical research contribute to advanced understanding and delivering of patient-safe healthcare.