COMMON TRANSFUSION DEVICES

Apart from the vascular access devices discussed earlier, some other commonly used devices for IV therapy (Fig. 32.8) are as follows:

Fig.

a. IV transfusion set is a long PVC tubing 120-150 cm with: (a) IV bottle connector at one end, (b) cannula/ needle connector at other end, (c) murphy's chamber at 6-12 cm away from bottle end, and (d) flow-rate regulator valve.

Murphy's chamber is used to regulate the flow rate of IV fluid by adjusting the number of drops (16-20 drops/ml) falling per minute. A fluid level must always be maintained in the Murphy's chamber, if necessary after resetting.

b. Blood transfusion set is similar to IV set, except that it contains a filter in Murphy's chamber to filter-out any clots in the infused blood.

c. Microdrip set is also similar to the IV set except that instead of Murphy's chamber, it has a two part PVC chamber. Upper chamber of microdrip set is graduated in ml with a usual capacity 100 ml and drains into lower chamber through a fine metallic needle to reduce the drop size (~60 drops/ml). Microdrip set is used to control accidental infusion of large volumes in very young children and to ensure finer drop-rate control during infusion of potentially hazardous drugs, e.g. dopamine, insulin, etc.

d. Three-way is a small T-shaped glass or PVC device, with two inlets and one outlet. Either of the inlets can be connected to the outlet with the help of a perpendicular knob/screw.

Three-way is commonly used as intermediary connection between Venflon (connected to outlet) and IV tubing (connected to one of the inlet). Third inlet allows: (a) additional IV drug delivery without disconnecting the line, (b) simultaneously CVP monitoring, (c) aspiration of blood samples. Three­way may also be connected during therapeutic throaco-/abdominocentesis to avoid need for repeated disconnections during aspiration and prevent air­entry in the cavity.

Fig. 32.9: Delee’s mucus extractor.

32.4