Venous access

Into an intermittent venous access device called a heparin lock (a small IV catheter in the patient s vein connected to a small fluid reservoir with a rubber cap through which the needle is inserted to administer the drug)... 

The drug will be administered three times weekly and can be given only via die IV or SC route or via venous access during dialysis. 

Administer intravenous drugs by rapid bolus followed with a 20 mL flush of intravenous fluid and extremity elevation for 10-20 s if peripheral venous access is utilized during resuscitation. 

Atropine, epinephrine, and lidocaine can be administered through the tracheal tube before venous access is achieved at 2-2.5 times the recommended intravenous dose diluted with 10 mL of normal saline or sterile water. Stop CPR, administer beyond the tip of the endotracheal tube, follow with five quick insufflations to aerosolize the drug, and then resume CPR. 

Fosphenytoin Fosphenytoin is a water-soluble, phospho-ester prodrug of phenytoin that is rapidly converted to phenytoin in the body. It is compatible with most IV solutions and is well tolerated as an IM injection, even with the large volumes associated with loading doses (20 to 30 mL).19 It is dosed in phenytoin equivalents (PE), and it can be infused three times as fast as phenytoin, up to 150 mg PE/minute. The loading dose for patients not taking phenytoin is 15 to 20 mg PE/kg. It can be an advantage to use IM fosphenytoin when IV access cannot be obtained immediately and in patients with poor venous access. Although it has fewer cardiovascular side... 

Reduced lean body mass Reduced muscle strength Reduced exercise performance Thin, dry skin cool peripheries poor venous access Depressed affect, labile emotions Impaired cardiac function... 

Because of the need for repeated venous access, a central venous catheter or infusion port is placed prior to starting treatment. These devices are useful not only for delivery of chemotherapy but also to support patients during periods of myelosuppression. Infection and bleeding complications are the primary cause of mortality in patients with leukemia. 

After performing a nutrition assessment and estimating nutritional requirements, determine the optimal route to provide specialized nutrition support (e.g., oral, enteral, or parenteral). If PN is deemed necessary, venous access (i.e., peripheral or central see below) for PN infusion must be obtained. Finally, formulate a PN prescription, and administer PN according to proper safety guidelines. 

PN can be administered via a smaller peripheral vein (e.g., cephalic or basilic vein) or via a larger central vein (e.g., superior vena cava). Peripheral PN (PPN) is infused via a peripheral vein and generally is reserved for short-term administration (up to 7 days) when central venous access is not available. PN formulations are hypertonic, and infusion via a peripheral vein can cause thrombophlebitis. Factors that increase the risk of phlebitis include high solution osmolarity, extreme pH, rapid infusion rate, vein properties, catheter material, and infusion time via the same vein.20 The osmolarity of PPN admixtures should be limited to 900 mOsm/L or less to minimize the risk of phlebitis. The approximate osmolarity of a PN admixture can be calculated from the osmolarities of individual components ... 

Transvenous pacing Insertion of a pacemaker into the heart via venous access for the purpose of pacing. 

Parenteral nutrition (PN) provides macro- and micronutrients by central or peripheral venous access to meet specific nutritional requirements of the patient, promote positive clinical outcomes, and improve quality of life. PN is also referred to as total parenteral nutrition or hyperalimentation. 

CPN is useful in patients who require PN for more than 7 to 14 days and who have large nutrient requirements, poor peripheral venous access, or fluctuating fluid requirements. 

Disadvantages include risks associated with catheter insertion, use, and care. Central venous access has a greater potential for infection. 

Patient case A patient s daily nutritional requirements have been estimated to be 100 g protein and 2,000 total kcal. The patient has a central venous access and reports no history of hyperlipidemia or egg allergy. The patient is not fluid restricted. The PN solution will be compounded as an individualized regimen using a single-bag, 24-hour infusion of a 2-in-1 solution with intravenous fat emulsion (IVFE) piggybacked into the PN infusion line. Determine the total PN volume and administration rate by calculating the macronutrient stock solution volumes required to provide the desired daily nutrients. The stock solutions used to compound this regimen are 10% crystalline amino acids (CAA), 70% dextrose, and 20% IVFE. 

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. 

The severity of magnesium depletion and presence of symptoms dictate the route of magnesium supplementation (Table 78-7). Intramuscular magnesium is painful and should be reserved for patients with severe hypomagnesemia and limited venous access. IV bolus injection is associated with flushing, sweating, and a sensation of warmth. 

Administration - Epoetin alfa may be given either as an IV or subcutaneous injection. In patients on hemodialysis, epoetin alfa usually has been administered as an IV bolus 3 times/week. While the administration is independent of the dialysis procedure, epoetin alfa may be administered into the venous line at the end of the dialysis procedure to obviate the need for additional venous access. In adult patients with CRF not on dialysis, epoetin alfa may be given either as an IV or subcutaneous injection. 

Absorption - Nalmefene is completely bioavailable following IM or subcutaneous administration. Nalmefene will be administered primarily as an IV bolus however, it can be given IM or subcutaneous if venous access cannot be established. While the time to maximum plasma concentration was 2.3 hours following IM and 1.5 hours following subcutaneous administrations, therapeutic plasma concentrations are likely to be reached within 5 to 15 minutes after a 1 mg dose in an emergency. 

Which route of administration is optimum Choosing the optimum dmg administration route takes into account the specific circumstances of each individual case. For example, can the patient tolerate oral medications, or is intravenous administration required Does the patient have venous access For how long can it be maintained Is intramuscular administration a possibility In many clinical situations, the available formulation determines the route of administration. Antibiotics are a prime example of this phenomenon ceftriaxone, for example, is available only for parenteral administration while amoxicillin is administered orally. 

Drug is administered chronically on an ambulatory basis with a portable infusion pump through a permanent central venous cathether peripheral IV infusions may be used temporarily until central venous access obtained... 

K.I. Akinwande, and D.M. Keehn, Dissolution of phenytoin precipitate with sodium bicarbonate in an occluded central venous access device. Ann. Pharmacother. 29 707-709, 1995. 

However, one disadvantage associated with the use of most recombinant molecules is their rapid clearance. Because of this rapid clearance, recombinant molecules require repeated administration to achieve biological efficacy. Initially, continuous infusion was used to address this pharmacological deficiency. Continuous infusion has the advantage of delivering drugs in a controlled manner and is particularly appropriate when it is important to maintain constant plasma drug concentrations. However, the requirement for continuous venous access and the use of ambulatory pumps limits its use. 

Restoration of function of central venous access devices as assessed by the ability to draw blood... 

Blood collection from the femoral artery is mentioned by Davis et al. (1994) after surgically preparing vascular access ports to the femoral artery. Using dogs with surgically instrumented indwelling venous access ports into the femoral vein and using a 6 min infusion instead of a intravenous bolus injection is mentioned by... 

Venous entries Venous access points (one or possibly two) must be created as quickly as possible and kept open. Circulatory stabilization by means of volume substitution, at best with monitoring of the central venous pressure, is crucial. Diagnostic or therapeutic endoscopy is only possible once the circulation has been adequately stabilized and any necessary fresh blood has been administered. 

Extravasation can cause severe local reactions, including tissue necrosis. Safe venous access, preferably via a central line is advisable. The recommendation to use sodium heparin or buffered dextrose is not supported by clinical data. 

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