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[Abstract] Background. Patients with cardiovascular (CV) disease have an increased circulating angiotensin-converting enzyme 2 (ACE2) activity, but there is little information about changes in ACE2 in chronic kidney disease (CKD) patients without history of CV disease. We examined circulating ACE2 activity in CKD patients at stages 3–5 (CKD3-5) and in dialysis (CKD5D) without any history of CV disease. Methods. Circulating ACE2 activity was measured in human ethylenediamine-tetraacetic acid (EDTA)-plasma samples from the NEFRONA study (n = 2572): control group (CONT) (n = 568), CKD3-5 (n = 1458) and CKD5D (n = 546). Different clinical and analytical variables such as gender; age; history of diabetes mellitus (DM), dyslipidemia and hypertension; glycaemic, renal, lipid and anaemia profiles; vitamin D analogues treatment and antihypertensive treatments (angiotensin-converting enzyme inhibitor and angiotensin receptor blockade) were analysed. Circulating ACE2 and ACE activities were measured using modified fluorimetric assay for EDTA-plasma samples, where zinc chloride was added to recover enzymatic activity. Results. In CKD3-5 and CKD5D, significant decrease in circulating ACE2 activity was observed when compared with CONT, but no differences were found between CKD3-5 and CKD5 when performing paired case-control studies. By multivariate linear regression analysis, male gender and advanced age were identified as independent predictors of ACE2 activity in all groups. Diabetes was identified as independent predictor of ACE2 activity in CKD3-5. Significant increase in the activity of circulating ACE was found in CKD3-5 and CKD5D when compared with CONT and in CKD5D when compared with CKD3-5. By multiple regression analysis, female gender and younger age were identified as independent predictors of ACE activity in CONT and CKD3-5. Diabetes was also identified as an independent predictor of ACE activity in CKD3-5 patients. Conclusions. Circulating ACE2 and ACE activities can be measured in human EDTA-plasma samples with zinc added to recover enzymatic activity. In a CKD population without previous history of CV disease, ACE2 activity from human EDTA-plasma samples directly correlated with the classical CV risk factors namely older age, diabetes and male gender. Our data suggest that circulating ACE2 is altered in CKD patients at risk for CV event.

Transoesophageal echocardiography is a new technique that allows continuous and noninvasive assessment of cardiac function during surgery. More recently this technique is being used to detect the presence of external objects into the cardiac cavities. We report a case of Swan-Ganz catheter knotting confirmed by this echocardiography technique. He was a 57 year old male with previous history of arterial hypertension and ischemic heart disease who was scheduled for surgery because poor response to medical therapy. After anesthetic induction a thermodilution catheter was introduced percutaneously into the right internal jugular vein under continuous pressure monitoring from the distal catheter hole. In view of the difficulties in introducing the catheter into the pulmonary artery an intravascular catheter knotting was suspected and a bidimensional transesophageal echocardiogram confirmed the diagnosis. During extracorporeal circulation the catheter was withdrawn through a right auriculotomy. Monitoring with a Swan-Ganz catheter, as other invasive monitoring techniques, is followed by a certain degree of complications which should be avoided by a careful manipulation. Echocardiography is a valuable diagnostic procedure to identify the position of monitoring catheters into the cardiac cavities.

Classically, the cardiac output is measured by the thermodilution method, employing a standard volume of 5% D/W at 4 degrees C. Recently, however, a room-temperature (17-24 degrees C) measurements have been used, in such a way that a lower gradient between the injectate and the patient temperature is established. This lact could question the sensitivity and reliability of the technique evaluated. We have studied 20 patients undergoing different operations, in whom the cardiac output was measured by injecting a standard volume of 5 ml 5% D/W at room-temperature or at 5 degrees C, randomly assigned, in order to evaluate any difference between the two techniques. Over a total of 100 cardiac output determinations taken in normothermic conditions (19-24 degrees C) the mean was 4.24 +/- 1.13 l/min (means +/- SD). In hypothermic conditions the cardiac output was 4.28 +/- 1.14 l/min (means +/- SD). Results showed no statistical difference between both methods.

We report the clinical case of a 56 years old male suffering dystrophic ampullar epidermolysis. He underwent brachial plexus blockade to remove a right hand tumor. The patient presented bilateral pseudosyndactylia, flexion retraction of the left hand, and erosive lesions in the inferior extremities, forearm, and trunk interfered monitorization and venous catheterization. Cutaneous friction or trauma should be carefully avoided since in this patient might produce detachment of the epidermis and subsequent ampullar formation. Cutaneous electrodes without adhesive components, padded sphygmomanometers, ear pulsimeter, and venous catheter sutured to the skin were used during monitorization. Anesthetic management of patients with dystrophic ampullar epidermolysis should consider careful airway manipulation, reduction of mucocutaneous contacts, prevention of pressure or friction skin trauma, appropriate electrolyte and plasma volume reposition, and use of nonadhesive material. To avoid airway manipulation regional anesthesia should be considered in patients with ampullar epidermolysis. We recommend regional anesthesia with ketamine.