The pathophysiology of hypertension in patients on renal replacement therapy is not yet clear, and the role of extracellular fluid overload is still a matter of debate. The main problem is the lack of techniques to determine the fluid state. Recently new noninvasive techniques have become available which make it possible to accurately determine the hydration state in these patients. We have studied the influence of the hydration state on interdialytic blood pressure in 45 patients: 21 (46.6%) using antihypertensive medication and 24 (53.4%) without antihypertensive medication. Total body water (TBW) was determined by bioelectrical impedance analysis performed just before a hemodialysis session. The TBW was then related to the fat-free mass calculated by the anthropometric method (aFFM) of Durnin. The hydration state was defined using the following formula: TBW/aFFM·100. Furthermore, for each patient the ideal TBW was calculated according to the Watson formula. The difference between TBW and ideal TBW was considered a further index of the hydration state. Ambulatory blood pressure monitoring was performed by using a Takeda 2420 recorder according to the Korotkoff method during the 24 h before the midweek hemodialysis session. Blood pressure monitoring showed a significant correlation with the hydration state of these patients. In conclusion, the hydration state seems to play a major role in interdialytic blood pressure control.

The persistence of a left superior vena cava is the result of a lack of an embryological involution of the left anterior cardinal vein. This anomaly is very rare: about 0.3% of the general population. Its incidence increases remarkably from 3-10% in those patients affected with congenital heart disease. Described herein is a case of persistent left superior vena cava, discovered by chance, following the placement of a central venous catheter for hemodialysis. A chest X-ray in projection back-forward showed the central venous catheter along the left sternal margin simulating a placement in the aorta artery. This clinical picture, as described in the literature, is often accompanied by other anatomical anomalies, in our case, by the congenital agenesis of a solitary pelvic kidney. In agreement with the literature and in contrast with what has been reported recently, we sustain that a central venous catheter placed, for any reason, in the persistent left superior vena cava must be removed immediately because it can induce hyperkinetic arrhythmia and cardiac arrest as in our case. Our case report should be a warning that lack of awareness of the anomalies of the big central veins can cause a rise in morbidity.

At present, the placement of a central venous catheter is becoming more and more a routine procedure nevertheless it involves different operators in fields such as oncology, nutrition, nephrology, and emergency medicine. It is well known that complications in the placement of CVC may occur in up to 20% of cases. One fifth of the catheters may result to be misplaced either in the internal omolateral jugular vein or in the innominate vein or in the controlateral brachiocephalic veins and usually a chest radiogram is necessary to evaluate its location. On the basis of 10 years of experience including more than 1,000 CVC placements, we now believe that endocavitary electrocardiography EC-ECG, initially studied and applied by Dr. Serafini, constitutes the best technique, more secure and more comfortable for the patient, to verify the position of the tip of a CVC. The technique EC-ECG, very simple and secure, utilizes the CVC as an endocavitary electrode. This is connected to a standard electrocardiograph, the same one to which the patient is connected during the placement of the CVC, and provides, in derivation V 1 or D 3 , an electrocardiographic pattern extremely sensitive to the position of the catheter tip. From December 1991 to December 2000, this technique has been used successfully in our departments of nephrology and applied to 1,139 patients that needed a CVC for hemodialysis. EC-ECG and a standard chest radiogram controlled the first 100 CVC we placed and in the other 1,039 cases, the control was made by EC-ECG alone. Only in 31 patients (2.7% of all cases), due to arrhythmia, the technique EC-ECG was not utilized. According to our experience, the procedure EC-ECG is an extremely reliable technique, sensitive and specific in 100% of cases, easy for the operator to perform, comfortable for patient. It doesn't need additional time to be performed and eliminates the need of taking a chest radiogram that up to now was considered indispensable in order to verify the position of the catheter tip. In this manner serious complications such as pneumothorax, and haemothorax that can complicate the placement of a CVC can also be avoided. Based on our experience, we now believe that this technique, that today has a large application in nephrology, oncology, clinical nutrition and in various branches of general medicine whenever the placement of a CVC is required, should be considered as a possible new guide line in controlling the placement of a CVC together with a chest X-ray when it is necessary.

Internal jugular vein cannulation has become a routine and clinically important aspect of medical care in hemodialysis patients. Mismanagement in the location of a central venous catheter may occur in up to 20% of cases. The aim of the study was to evaluate the utility of endocavitary electrocardiography in right internal jugu-lar vein placement of central venous catheters. We examined 327 central venous catheterizations performed in two Dialysis Units; all catheters were positioned using intra-atrial ECG monitoring by guide-wire and after, by catheter filled with NaCl solution. EC-ECG via guide-wire was successful on 321 occasions (98.1%). Correct placement of the catheter was confirmed by EC-ECG via catheter in each case, and by plain chest-X-ray only in the first hundred cases. In 314 patients (98.1%), insertion of the catheter was successful at the first attempt. In 6 catheterizations, no atrial trace was obtained due to atrial fibrillation in 4 cases, and in 2 cases technical error and guide-wire looping into a right jugular vein. Complications as a direct result of guide-wire or catheter placement were not observed. In our opinion this method can be used safely and makes radiological control usually unnecessary. (The Journal of Vascular Access 2001; 2: 45-50).

No abstract