f. Prothrombin Time. The prothrombin time procedure detects abnormalities
in the clotting time in some stages of the clotting process. If certain amounts of
thromboplastin, calcium, and citrated plasma are carefully mixed under controlled
conditions, fibrin strands will normally form within seconds. The time between the
addition of plasma and the formation of the fibrin web is read. Normal values are 12 to
15 seconds. The prothrombin activity of the patient's plasma has important significance
in diseases of the liver, in vitamin K deficiency, and in the use of dicumarol as an
Section III. INFUSION PROCEDURES
The intravenous infusion is often started by the combat medical specialist or the
medical NCO in the field during a battle situation. The following method is essentially a
review of the technique that was taught during medical training. This procedure
requires practice under the supervision of a trainer who is experienced in the procedure.
Mastery of the following material should not be interpreted as mastery of this task. It
cannot substitute for hands-on supervised training and practice.
3-23. EQUIPMENT REQUIRED FOR THE INFUSION
The equipment used for both the infusion and the transfusion have many
similarities and some differences. The equipment for the infusion is normally available
in the field. Usually, the transfusion setup is available where blood products are
a. Containers. There are three types of fluid container systems in current use,
the closed system, the open system, and the plastic bag (see figure 3-1).
(1) Closed system. The closed system bottle has an air vent through which
medication may be added. A filter must be removed and then replaced. The sterility of
the solution can be destroyed by careless handling of this filter.
(2) Open system. The open system bottle draws in added medication by
vacuum, so this vacuum must be carefully maintained. The level of fluid remaining in
the bottle is easily noted in both the open and closed systems.
(3) Plastic bag. The plastic bag has a port for adding the medication, but
has no vacuum. Special care must be taken to be sure that the set is clamped off and
medication is well mixed to prevent the patient from getting a toxic dose of the
medication. It is difficult to judge the fluid remaining in the bag because it collapses as
the fluid is withdrawn. Figure 3-2 shows medication being added to the three systems.
b. Drip Chamber. The drip chamber measures the rate of flow, as ordered by
the doctor. There are several types of chambers. An example is shown in figure 3-3.