Clinical aspects on central venous cannulation

Abstract: Central venous catheters are mainly being used for reliable infusion of fluids and potentially irritant drugs, for haemodialysis, and for assessment of right atrial or central venous pressure (RAP/CVP). Current guidelines state that central venous catheterization should be followed-up by immediate anterior-posterior chest X-ray to confirm appropriate positioning and to detect iatrogenic pneumothorax. However, the appropriate position is still questioned, and pneumothorax requiring therapeutic intervention may be detectable from clinical signs. A rare but serious complication of central venous cannulation is inadvertent arterial catheterization. Traditional pull and press techniques are associated with considerable risks when applied in noncompressible areas or when large bore catheters have been used. Repair of intrathoracic arteries may require extensive surgical or sophisticated endovascular approaches. The RAP/CVP have been reported to correlate with central venous return of blood and with peripheral venous pressure (PVP). Cuff-occluded rate of rise of peripheral venous pressure (CORRP), reflecting changes in PVP during proximal venous occlusion, has been proposed to predict hyper- or hypovolemia in dogs. In Study I patients with central venous cannulations were recorded prospectively. Individual radiographic records of corresponding routine control X-ray procedures were evaluated retrospectively. There were few complications from malpositioned catheter tips associated with short-term use. In Study II echocardiographic, and central and peripheral venous pressure measurements were made in patients with renal failure before and after haemodialysis. The changes in CORRP were found to correlate linearly with the volumes of fluid removed, whereas changes in RAP/CVP and PVP correlated with each other. In Study III inadvertent arterial catheterization after failed central venous cannulation was retrospectively found to be associated with obesity, emergency puncture, severe hypovolemia or lack of ultrasonic guidance, and to be successfully managed by endovascular therpeutic techniques. In Study IV records of routine control x-ray procedures after central venous catheterization were evaluated retrospectively, together with study protocol and medical charts. All iatrogenic pneumothoraces requiring therapeutic intervention were associated with clinical signs of respiratory distress or hypoxia. In conclusion, the results of this thesis indicate that routine post-procedural X-ray may be replaced by optional X-ray in selected patients, that CORRP (but not RAP/CVP) may predict changes in fluid balance, and that endovascular management is a feasible and safe therapeutic option in inadvertent arterial catheterization.