Infusion therapy limitations

The other advantage of this method is autonomy of the device action. The device is fixed on the patient,s neck and does not limit his movements. The patient who receives the infusion therapy does not require stay in the bed and constant observation by medical staff (Fig. 3). There are practically no mechanical reasons which can prevent to infuse drug into the catheter. "Push out" pressure is 400-500 mm of Mercury and resting of catheters exit port against any obstacle excludes possibility of its thrombosing and stopping of the system. 

Several adaptive mechanisms by the kidney limit effectiveness of loop diuretic therapy. Postdiuretic sodium retention occurs as the concentration of diuretic in the loop of Henle decreases. This effect can be minimized by decreasing the dosage interval (i.e., dosing more frequently) or by administering a continuous infusion. Continuous infusion loop diuretics may be easier to titrate than bolus dosing, requires less nursing administration time, and may lead to fewer adverse reactions. 

Potassium is the second most abundant cation in the body and is found primarily in the intracellular fluid. Potassium has many important physiologic functions, including regulation of cell membrane electrical action potential (especially in the myocardium), muscular function, cellular metabolism, and glycogen and protein synthesis. Potassium in PN can be provided as chloride, acetate, and phosphate salts. One millimole of potassium phosphate provides 1.47 mEq of elemental potassium. Generally, the concentration of potassium in peripheral PN (PPN) admixtures should not exceed 80 mEq/L (80 mmol/L). While it is safer to also stick to the 80 mEq/L (80 mmol/L) limit for administration through a central vein, the maximum recommended potassium concentration for infusion via a central vein is 150 mEq/L (150 mmol/L).14 Patients with abnormal potassium losses (e.g., loop or thiazide diuretic therapy) may have higher requirements, and patients with renal failure may require potassium restriction. 

Cyclic PN (e.g., 12 to 18 hours/day) is useful in hospitalized patients who have limited venous access and require other medications necessitating interruption of PN infusion, to prevent or treat hepatotoxicities associated with continuous PN therapy, and to allow home patients to resume normal lifestyles. Patients with severe glucose intolerance or unstable fluid balance may not tolerate cyclic PN. 

Adults - 10 mL (elemental iron 125 mg), may be diluted in 100 mL 0.9% sodium chloride administered by intravenous (IV) infusion over 1 hour. It may also be administered undiluted as a slow IV injection (at a rate up to 12.5 mg/min). Most patients will require a minimum cumulative dose of 1 g elemental iron administered over 8 sessions at sequential dialysis treatments to achieve a favorable hemoglobin or hematocrit response. Patients may continue to require therapy with IV iron at the lowest dose necessary to maintain the target levels of hemoglobin, hematocrit, and laboratory parameters of iron storage within acceptable limits. 

Cyclicity of administration is vital in the use of 5-FU as a radiosensitizer. The concept of cyclical treatment has been well established in cancer chemotherapy and alien to classical radiation therapy (where it is termed split-course therapy). 5-FU radio-sensitizes tumor tissue as well as normal cells. However, this normal tissue radio-sensitizationis limited to the irradiated field. Suitable fractionation (i.e., cyclical therapy) can permit rapid normal tissue recovery (23). The results of infused 5-FU and radiation in head and neck cancer supports the principle that cyclical treatment with 5-FU does not suffer from the limitations apparent in split-course radiation treatments. 

Therapy, to be effective, depends upon administration of an adequate number of platelets, generally 5 X 10 in a 70 kg man or a 60 kg woman given over 15 minutes - with suitable adjustment for body surface area in children. It is mandatory that the increment is calculated and the duration of response be documented at 24 hours. The optimum practice is to relate the number infused to changes achieved in the patient by means of the corrected count index. This step anticipates the emergence of resistance that limits the value of repeated transfusions. Occasional allergic reactions have to be blocked by premedication with an intravenous injection 100 mg of hydrocortisone, 12.5 mg of phenergan and 1 g of paracetamol... 

The limiting side effect associated with orally administered Pz-adrenoceptor agonists is muscle tremor, which results from a direct stimulation of Pz-adreno-ceptors in skeletal muscle. This effect is most notable on the initiation of therapy and gradually improves on continued use. 2-Agonists also cause tachycardia and palpitations in some patients. When used by intravenous infusion for premature labor, P2-agonists have been re-... 

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