Intravascular procedure

Amide-type agents include articaine, lidocaine, bupivacaine, prilocaine, mepivacain and ropiva-caine. These are metabolized in the liver by microsomal enzymes with amidase activity. The amide group is preferred for parenteral and local use. If by accident rapidly administered intravascularly these agents, especially bupivacaine but also lidocaine, can produce serious and potentially lethal adverse effects including convulsions and cardiac arrest. They can more easily accumulate after multiple administrations. Intravenous lidocaine is sometimes used for regional anesthesia, for infiltration procedures, for the induction of nerve blockade and for epidural anesthesia. However, it is also used as an antiarrhythmic. Bupivacaine is a long-acting local anesthetic used for peripheral nerve blocks and epidural anesthesia. 

The usefulness of diuretics in the management of CHF cannot be overstated. Before diuretics were available, rotating tourniquets were used to diminish venous return by ligating the lower extremities. Less venous blood returned to the right side of the heart and pooled in the legs. This procedure diminished the effective intravascular volume that would otherwise have accumulated in the lungs. The availability of loop diuretics (particularly furosemide) has resulted in the virtual elimination of this practice. 

Zhang, G., V. Budker, P. Williams, K. Hanson, and J.A. Wolff, Surgical procedures for intravascular delivery of plasmid DNA to organs. Methods Enzymol, 2002. 346 125-33. 

Platelet glycoprotein Ilb/llla (GPIIb/llla) receptor inhibitors are widely used to prevent thrombotic vascular events, especially in patients with acute coronary syndromes (ACS) or in those undergoing intravascular interventional procedures. The purpose of this chapter is to evaluate the quality and magnitude of the clinical trial evidence in support of their use, In addition, key issues regarding their optimal application in clinical practice will be discussed. 

RF catheter ablation is complicated by thromboembolism in about 0.6% of patients (23). The risk of stroke from RF ablation may be higher in paroxysmal AF patients with prior TIA (24). As reflected by elevated plasma D-dimer levels, RF ablation has a thrombogenic effect that persists through the first 48 hours after the procedure (25). Activation of the coagulation cascade in RF ablation procedures is not related to the delivery of RF energy, but is related to the placement of intravascular catheters and to the duration of the ablation procedure (26,27). Furthermore, RF lesions themselves have been shown to be thrombogenic (28). The risk of a thromboembolic complication is higher for left-sided ablations... 

Rote et al. (1993, 1994) used a carotid thrombosis model in dogs. A calibrated electromagnetic flow meter was placed on each common carotid artery proximal to both the point of insertion of an intravascular electrode and a mechanical constrictor. The external constrictor was adjusted with a screw until the pulsatile flow pattern decreased by 25 % without altering the mean blood flow. Electrolytic injury to the intimal surface was accomplished with the use of an intravascular electrode composed of a Teflon-insulated silver-coated copper wire connected to the positive pole of a 9-V nickel-cadmium battery in series with a 250000 ohm variable resistor. The cathode was connected to a subcutaneous site. Injury was initiated in the right carotid artery by application of a 150 xA continuous pulse anodal direct current to the intimal surface of the vessel for a maximum duration of 3 h or for 30 min beyond the time of complete vessel occlusion as determined by the blood flow recording. Upon completion of the study on the right carotid, the procedure for induction of vessel wall injury was repeated on the left carotid artery after administration of the test drug. 

These structures have important implications for blood transfusions and other transplantation procedures. If an antigen not normally present in a person is introduced, the person s immune system recognizes it as foreign. Adverse reactions can ensue, initiated by the intravascular destruction of the incompatible red blood cells. 

Fluosol s shortcomings included prolonged organ retention of F-tripropylamine (reticuloendothelial system (RES) half-life 65 days), complement activation, and hemodynamic effects due to Pluronic, excessive dilution, limited intravascular persistence, insufficient stability, and lack of user-friendliness. The product came as three separate preparations the frozen stem emulsion and two annex salt solutions. The stem emulsion had to be carefully thawed, then admixed sequentially to the annex solutions, and the reconstituted product had to be used within 8 h. This cumbersome procedure, the short window for use, the further need for administering a small-test dose to patients prior to infusion in order to identify those patients who were sensitive to Pluronic, contributed to compromising the product s commercial success. 

The protective effects of intravenous hydration alone (0.45% isotonic saline, 1 ml/kg/hour for 12 hours before and 12 hours after contrast administration), fenoldopam (0.1 microgram/kg/minute for 4 hours before and 4 hours after the procedure), and acetylcysteine (600 mg bd 24 for hours before and 24 hours after the procedure) have been compared in preventing contrast nephrotoxicity after intravascular administration of low-osmolar non-ionic contrast medium (199). The incidence of nephrotoxicity was 15% in the hydration group, 16% in the fenoldopam group, and 18% in the acetylcysteine group. AU the groups were comparable and basehne creatinine clearance was about 60 ml/minute in aU the patients who received a similar dose of the contrast medium (1.5 ml/ kg). The authors concluded that fenoldopam and acetylcysteine do not offer extra protection against contrast nephrotoxicity over hydration alone. 

The authors proposed that some or all of the local anesthetic had been inadvertently injected intravascularly, despite negative aspiration tests. There were no cardiovascular complications, underlining the proposed greater cardiovascular safety of levobupivacaine over bupivacaine. The authors accepted that if the patient had been awake during the procedure, earlier detection of neurological symptoms might have been possible. 

Greater use of nonionic contrast media for routine X-ray procedures is clearly the trend of the future. It was estimated that in 1991, approximately 69% of the procedures performed in the United States used nonionic contrast media compared to about 66% in Europe and more than 80%in Japan. In 1994 the percentage increased to about 80% in the United States, 75% in Europe, and 92%in Japan (540). In the United States, in 1994 as many as 18 million patients received intravascular contrast media, and an estimated 170 million contrast medium-enhanced radiologic studies were performed from 1978 to 1994 (541). 

Benenah JF. Intravascular ultrasound The role in diagnostic and therapeutic procedures. Cardiol Chn 1997 15 141-159. 

Vigorous fluid resuscitation and support of respiratory, renal, cardiovascular, and hepatobiliary function may limit systemic complications. " However, there is no proven method to prevent these complications. While hemoconcentration (decreased intravascular volume) is strongly associated with pancreatic necrosis, it is not clear whether aggressive fluid resuscitation alone during the first 24 hours can prevent pancreatic necrosis." Procedures such as ERCP, hypothermia, nasogastric suction, pancreatic irradiation, peritoneal lavage, and thoracic duct drainage remain unproven. ... 

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