"Half-way" venous catheters. III. Tip displacements with movements of the upper extremity.

Directions and sizes of displacement of "half-way" catheter tips with movements of the upper extremities were investigated in thoracic radiographs in 21 patients (10 women and 11 men), 28-88 years old. Ten catheters were inserted by basilic, and 11 by cephalic veins punctured at the fossa cubiti. Catheter tip positions were related to the lateral edge of the first rib. The tip position with the patient's arm in 90 degree abduction was considered as the reference point. Displacements caused by maximal flexion of the forearm, maximal adduction of the upper extremity, and maximal elevation of the brachium plus maximal flexion of the forearm were studied. With all movements and venous approaches there were significantly more medial than lateral displacements (P less than 0.001). The medial displacements varied from 0.2-5.0 cm, and the lateral ones from 0.5-1.8 cm. Location of the "half-way" catheter tips in the proximal axillary vein, at the lateral edge of the first rib, is recommended. As found previously, this may be obtained by inserting a catheter length representing 1/5 of the patient's height. Such a location inhibits harbouring of the "half-way" catheter tips in the jugular veins with movement in the upper extremities. Furthermore, estimation of central venous pressures by axillary venous pressures is not affected.