This procedure prevents the blood from clotting in the needle and possibly may help to reduce the occurrence of thrombophlebitis. However, the optimum dose of heparin to satisfy both criteria has not yet been established. Indeed, an uncontrolled hospital study in adults suggested that 0.9 percent sodium chloride solution was as effective as heparin in preventing needle occlusion and reducing the incidence of thrombophlebitis. The doses of heparin and saline used were 100 units/ml and 10 units/ ml, the usual standard doses used in children. Hypersensitivity reactions to heparin are extremely rare. It is important to flush the intravenous system before each bolus administration of antibiotics or other agents because incompatibility has been reported between heparin and some antibiotics (eg, amikacin, tobramycin, methicillin). starlix medication
The development of topical anesthetic agents and the improvements in the manufacture of intravenous cannulas and other venous access systems has resulted in painless and well-tolerated procedures, even in very small children with CF. There is little to choose between the various cannulas available. The longevity of a cannula depends on the particular antibiotic used and the way it is administered. On average an intravenous cannula will remain usable for 6 to 8 days if a third-generation cephalosporin is employed as the sole antibiotic in the treatment
Other methods of venous access are (1) a percutaneous central venous cannula, and (2) continuous venous access (PAC or Port-a-Cath/Pharmacia, Infuse-a-port [Infusaid], etc). The catheter used in percutaneous central venous access remains accessible for 3 to 5 days longer than a peripheral venous cannula. The continuous venous access systems consist of either a stainless steel or a rigid plastic disk chamber with a port for injection which is connected to a silicone catheter. These systems remain relatively free of infections because they are closed and implantable devices. General anesthesia may be required for setting the system up. Occasional problems have occurred when the catheter became dislodged or was accidentally disconnected, and infarcts may occur if the catheter is badly placed in a growing child. These systems are particularly useful in adolescents and adults with CF in whom the peripheral venous access may be inadequate or already scarified from previous frequent use.