Fluid, Electrolyte, and Acid-Base Balance

Active Transport: Fluids in different body compartments have different concentrations of electrolytes that are necessary for normal function. For example, concentrations of Na⁺, Cl⁻, and are higher in the ECF than in the ICF, whereas the concentrations of K⁺, Mg²⁺, and PO³⁻₄ are higher in the ICF than in the ECF. Cells maintain their high intracellular electrolyte concentration by active transport. Active transport requires energy in the form of adenosine triphosphate (ATP) to move electrolytes across cell membranes against the concentration gradient (from areas of lower concentration to areas of higher concentration). One example of active transport is the sodium-potassium pump, which moves Na⁺ out of a cell and K⁺ into it, keeping ICF lower in Na⁺ and higher in K⁺ than the ECF.

Diffusion: Diffusion is passive movement of electrolytes or other particles down the concentration gradient (from areas of higher concentration to areas of lower concentration). Within a body compartment electrolytes diffuse easily by random movements until the concentration is the same in all areas. However, diffusion of electrolytes across cell membranes requires proteins that serve as ion channels. For example, when a sodium channel in a cell membrane is open, Na⁺ diffuses passively across the cell membrane into the ICF because concentration is lower in the ICF. Opening of ion channels is tightly controlled and plays an important part in muscle and nerve function.

Osmosis: Water moves across cell membranes by osmosis, a process by which water moves through a membrane that separates fluids with different particle concentrations (Fig. 41-3). Cell membranes are semipermeable, which means that water crosses them easily but they are not freely permeable to many types of particles, including electrolytes such as sodium and potassium. These semipermeable cell membranes separate interstitial fluid from ICF. The fluid in each of these compartments exerts osmotic pressure, an inward-pulling force caused by particles in the fluid. The particles already inside the cell exert ICF osmotic pressure, which tends to pull water into the cell. The particles in the interstitial fluid exert interstitial fluid osmotic pressure, which tends to pull water out of the cell. Water moves into the compartment that has a higher osmotic pressure (inward-pulling force) until the particle concentration is equal in the two compartments.

If the particle concentration in the interstitial compartment changes, osmosis occurs rapidly and moves water into or out of cells to equalize the osmotic pressures. For example, when a hypotonic solution (more dilute than normal body fluids) is administered intravenously, it dilutes the interstitial fluid, decreasing its osmotic pressure below intracellular osmotic pressure. Water moves rapidly into cells until the two osmotic pressures are equal again. On the other hand, infusion of a hypertonic intravenous (IV) solution (more concentrated than normal body fluids) causes water to leave cells by osmosis to equalize the osmolality between interstitial and intracellular compartments.

Filtration: Fluid moves into and out of capillaries (between the vascular and interstitial compartments) by the process of filtration (Fig. 41-4). Filtration is the net effect of four forces, two that tend to move fluid out of capillaries and small venules and two that tend to move fluid back into them (Rose, 2011). Hydrostatic pressure is the force of the fluid pressing outward against a surface. Similarly, capillary hydrostatic pressure is a relatively strong outward-pushing force that helps move fluid from capillaries into the interstitial area. Interstitial fluid hydrostatic pressure is a weaker opposing force that tends to push fluid back into capillaries.

Blood contains albumin and other proteins known as colloids. These proteins are much larger than electrolytes, glucose, and other molecules that dissolve easily. Most colloids are too large to leave capillaries in the fluid that is filtered, so they remain in the blood. Because they are particles, colloids exert osmotic pressure. Blood colloid osmotic pressure, also called oncotic pressure, is an inward-pulling force caused by blood proteins that helps move fluid from the interstitial area back into capillaries. Interstitial fluid colloid osmotic pressure normally is a very small opposing force.

At the arterial end of a normal capillary, capillary hydrostatic pressure is strongest, and fluid moves from the capillary into the interstitial area, bringing nutrients to cells. At the venous end capillary hydrostatic pressure is weaker, and the colloid osmotic pressure of the blood is stronger. Thus fluid moves into the capillary at the venous end, removing waste products from cellular metabolism. Lymph vessels remove any extra fluid and proteins that have leaked into the interstitial fluid.

Disease processes and other factors that alter these forces may cause accumulation of excess fluid in the interstitial space, known as edema. For example, people with heart failure develop edema. In this situation, venous congestion from a weakened heart, which no longer pumps effectively, increases capillary hydrostatic pressure, causing edema by moving excessive fluid into the interstitial space. Inflammation is another cause of edema. It increases capillary blood flow and allows capillaries to leak colloids into the interstitial space. The resulting increased capillary hydrostatic pressure and increased interstitial colloid osmotic pressure produce localized edema in the inflamed tissues.

Antidiuretic Hormone: ADH regulates the osmolality of the body fluids by influencing how much water is excreted in urine. It is synthesized by neurons in the hypothalamus that release it from the posterior pituitary gland. ADH circulates in the blood to the kidneys, where it acts on the collecting ducts (Koeppen and Stanton, 2008). Its name—antidiuretic hormone—tells you what it does. It causes renal cells to resorb water, taking water from the renal tubular fluid and putting it back in the blood. This action decreases urine volume, concentrating the urine while diluting the blood by adding water to it (see Fig. 41-6, A).

People normally have some ADH release to maintain fluid balance. More ADH is released if body fluids become more concentrated. Factors that increase ADH levels include severely decreased blood volume (e.g., dehydration, hemorrhage), pain, stressors, and some medications.

ADH levels decrease if body fluids become too dilute. This allows more water to be excreted in urine, creating a larger volume of dilute urine and concentrating the body fluids back to normal osmolality. For example, ethyl alcohol decreases ADH release, which causes people to urinate frequently when they drink alcoholic beverages.

Renin-Angiotensin-Aldosterone System: The renin-angiotensin-aldosterone system (RAAS) regulates ECF volume by influencing how much sodium and water are excreted in urine. It also contributes to regulation of blood pressure. Specialized cells in the kidneys release the enzyme renin, which acts on angiotensinogen, an inactive protein secreted by the liver that circulates in the blood. Renin converts angiotensinogen to angiotensin I, which other enzymes in the lung capillaries convert to angiotensin II (Koeppen and Stanton, 2008). Angiotensin II has several functions, one of which is vasoconstriction in some vascular beds. The important fluid homeostasis functions of angiotensin II include stimulation of aldosterone release from the adrenal cortex.

Aldosterone circulates to the kidneys, where it causes resorption of sodium and water in isotonic proportion in the distal renal tubules. Removing sodium and water from the renal tubules and returning it to the blood increases the volume of the ECF (see Fig. 41-6, B). Aldosterone also contributes to electrolyte and acid-base balance by increasing urinary excretion of potassium and hydrogen ions.

To maintain fluid balance, normally some action of the RAAS occurs. Certain stimuli increase or decrease the activity of this system to restore fluid balance. For example, if hemorrhage or vomiting decreases the extracellular fluid volume (ECV), blood flow decreases through the renal arteries, and more renin is released. This increased RAAS activity causes more sodium and water retention, helping to restore ECV.

Atrial Natriuretic Peptide: Atrial natriuretic peptide (ANP) also regulates ECV by influencing how much sodium and water are excreted in urine. Cells in the atria of the heart release ANP when they are stretched (e.g., by an increased ECV). ANP is a weak hormone that inhibits ADH by increasing the loss of sodium and water in the urine (see Fig. 41-6, C). Thus ANP opposes the effect of aldosterone (Koeppen and Stanton, 2008).

Excretion of Carbonic Acid: When you exhale, you excrete carbonic acid in the form of CO₂ and water. If the PaCO₂ (i.e., level of CO₂ in the blood) rises, the chemoreceptors trigger faster and deeper respirations to excrete the excess. If the PaCO₂ falls, the chemoreceptors trigger slower and shallower respirations so more of the CO₂ produced by cells remains in the blood and makes up the deficit. These alterations in respiratory rate and depth maintain the carbonic acid portion of acid-base balance (Coggon, 2008a). Sometimes people who have lung disease have difficulty with normal excretion of carbonic acid, which causes it to accumulate and make the blood more acid.

Excretion of Metabolic Acids: The kidneys excrete all acids except carbonic acid. They secrete H⁺ into the renal tubular fluid, putting back into the blood at the same time. If there are too many H⁺ ions in the blood, renal cells move more H⁺ ions into the renal tubules for excretion, retaining more in the process. If there are too few H⁺ ions in the blood, renal cells secrete fewer H⁺ ions.

Phosphate buffers in the renal tubular fluid keep the urine from becoming too acidic when the kidneys excrete H⁺ ions. If the kidneys need to excrete a lot of H⁺, renal tubular cells secrete ammonia, which combines with the H⁺ ions in the tubules to make , ammonium ions. Buffering by phosphate and the creation of NH₄⁺ turn free H⁺ ions into other molecules in the renal tubular fluid (Rose, 2011). This process enables metabolic acid excretion in urine without making urine too acidic. People who have kidney disease often have difficulty with normal excretion of metabolic acids.

Respiratory Disorders: Many acute respiratory disorders predispose patients to respiratory acidosis. For example, bacterial pneumonia causes alveoli to fill with exudate that impairs gas exchange, causing the patient to retain carbon dioxide, which leads to increased PaCO₂ and respiratory acidosis.

Burns: Burns place patients at high risk for ECV deficit from numerous mechanisms, including plasma-to-interstitial fluid shift and increased evaporative and exudate output. The greater the body surface burned, the greater is the fluid loss (Copstead and Banasik, 2010). Patients with burns often develop metabolic acidosis because of greatly increased cellular metabolism, which produces more metabolic acids than their kidneys are able to excrete.

Trauma: Hemorrhage from any type of trauma causes ECV deficit from blood loss. Some types of trauma create additional risks. For example, crush injuries cause hyperkalemia. The trauma from the crush injury destroys the cellular structure, resulting in a massive release of intracellular K⁺ into the blood.

Head injury typically alters ADH secretion. It may cause diabetes insipidus (secretion of too little ADH), in which patients excrete large volumes of very dilute urine and develop hypernatremia. In contrast, head injury may cause the syndrome of inappropriate antidiuretic hormone (SIADH), in which excess secretion of ADH causes hyponatremia by retaining too much water and concentrating the urine (Copstead and Banasik, 2010).

Cancer: The types of fluid and electrolyte imbalances that occur with cancer depend on the type and progression of the cancer and treatment regimen. Many patients with cancer develop hypercalcemia when their cancer cells secrete chemicals that circulate into bones and cause calcium to enter the blood. Other fluid and electrolyte imbalances occur in cancer because some types of tumors cause metabolic and endocrine abnormalities. In addition, patients with cancer are at risk for fluid and electrolyte imbalances as a result of the side effects (e.g., anorexia, diarrhea) of chemotherapy, biological response modifiers, or radiation (Copstead and Banasik, 2010).

Heart Failure: Patients who have chronic heart failure have diminished cardiac output, which reduces kidney perfusion and activates the RAAS. The action of aldosterone on the kidneys causes ECV excess and risk of hypokalemia. Most diuretics used to treat heart failure increase the risk of hypokalemia while reducing the ECV excess. Dietary sodium restriction is important with heart failure because Na⁺ holds water in the ECF, making the ECV excess worse. In severe heart failure restriction of both fluid and sodium is prescribed to decrease the workload of the heart by reducing excess circulating fluid volume (Copstead and Banasik, 2010).

Oliguric Renal Disease: Oliguria occurs when the kidneys have a reduced capacity to make urine. Some conditions, such as acute rephritis, cause a sudden onset of oliguria, whereas other problems, such as chronic kidney disease, lead to chronic oliguria. Oliguric renal disease prevents normal excretion of fluid, electrolytes, and metabolic acids, resulting in ECV excess, hyperkalemia, hypermagnesemia, hyperphosphatemia, and metabolic acidosis. The severity of these imbalances is proportional to the degree of renal failure. Although chronic kidney disease is progressive, successful management of imbalances is possible with dietary restriction of sodium and other electrolytes, fluid restriction in severe cases, and eventually dialysis or renal transplant (Copstead and Banasik, 2010).

• The patient will be free of complications associated with the IV device throughout the duration of IV therapy.

• The patient will demonstrate balanced I&O measurements within 48 hours.

• The patient will have serum electrolytes within the normal range within 48 hours.

Enteral Replacement of Fluids: Oral replacement of fluids and electrolytes is appropriate as long as the patient is not so physiologically unstable that oral fluids cannot be replaced rapidly. Oral replacement of fluids is contraindicated when the patient has a mechanical obstruction of the GI tract, is at high risk for aspiration, or has impaired swallowing. Some patients unable to tolerate solid foods are still able to ingest fluids. Strategies to encourage fluid intake include offering small sips of fluid frequently, popsicles, and ice chips. Record one half the volume of the ice chips in I&O measurement. For example, if a patient ingests 240 mL of ice chips, you record 120 mL of intake. Encourage patients to keep their own record of intake to involve them actively. Family members who are properly instructed can also assist. Pay attention to each patient’s preferred temperature of oral fluids. Cultural beliefs regarding appropriate fluid temperature may interfere with fluid intake unless the fluid with the preferred temperature is available (Box 41-5).

When replacing fluids by mouth in a patient with ECV deficit, choose fluids that contain sodium (e.g., Pedialyte and Gastrolyte). Liquids containing lactose, caffeine, or low-sodium content are not appropriate when a patient has diarrhea.

A feeding tube is appropriate when the patient’s GI tract is healthy but the patient cannot ingest fluids (e.g., after oral surgery or with impaired swallowing). Options for administering fluids include gastrostomy or jejunostomy instillations or infusions through small-bore nasogastric feeding tubes (see Chapter 44).

Restriction of Fluids: Patients who have hyponatremia usually require restricted water intake. Patients who have very severe ECV excess sometimes have both sodium and fluid restrictions. Fluid restriction often is difficult for patients, particularly if they take medications that dry the oral mucous membranes or if they are mouth breathers. Explain the reason that fluids are restricted and ensure that the patient and family visitors know the amount of fluid permitted orally and understand that ice chips, gelatin, and ice cream are fluids. Help the patient decide the amount of fluid to drink with each meal, between meals, before bed, and with medications. It is important to allow patients to choose preferred fluids unless contraindicated. Frequently patients on fluid restriction can swallow a number of pills with as little as 1 oz (30 mL) of liquid.

In acute care settings fluid restrictions usually allot half the total oral fluids between 7 am and 3 pm, the period when patients are more active, receive two meals, and take most of their oral medications. Offer the remainder of the fluids during the evening and night shifts. Patients on fluid restriction need frequent mouth care to moisten mucous membranes, decrease the chance of mucosal drying and cracking, and maintain comfort (see Chapter 39).

Parenteral Replacement of Fluids and Electrolytes: Fluid and electrolytes may be replaced through infusion of fluids directly into veins (intravenously) rather than via the digestive system. Parenteral replacement includes parenteral nutrition (PN), IV fluid and electrolyte therapy (crystalloids), and blood and blood component (colloids) administration. IV devices are called peripheral IVs when the catheter tip lies in a vein in one of the extremities; they are called central venous IVs when the catheter tip lies in the central circulatory system (e.g., in the vena cava close to the right atrium of the heart) (Fig. 41-13).

Practice standard body fluid precautions when administering parenteral fluids (see Chapter 28) to minimize your own risk for exposure to bloodborne pathogens. Read and understand the policy and procedures for parenteral infusions at the institution for which you work.

Intravenous Therapy (Crystalloids): The goal of IV fluid administration is to correct or prevent fluid and electrolyte disturbances. It allows for direct access to the vascular system, permitting the continuous infusion of fluids over a period of time. You regulate IV fluid therapy continuously because of ongoing changes in a patient’s fluid and electrolyte balance. To provide safe and appropriate therapy to patients who require IV fluids, you need knowledge of the correct ordered solution, the reason the solution was ordered, the equipment needed, the procedures required to initiate an infusion, how to regulate the infusion rate and maintain the system, how to identify and correct problems, and how to discontinue the infusion.

Vascular Access Devices: Vascular access devices (VADs) are catheters or infusion ports designed for repeated access to the vascular system. Peripheral catheters are for short-term use (e.g., fluid restoration after surgery and short-term antibiotic administration). Devices for long-term use include central catheters and implanted ports, which empty into a central vein. Remember that the term central applies to the location of the catheter tip, not to the insertion site. Peripherally inserted central catheters (PICC lines) enter a peripheral arm vein and extend through the venous system to the superior vena cava where they terminate. Other central lines enter a central vein such as the subclavian or jugular vein or are tunneled through subcutaneous tissue before entering a central vein. Central lines are more effective than peripheral catheters for administering large volumes of fluid, PN, and medications or fluids that irritate veins. Proper care of central line insertion sites is critical for the prevention of catheter-related bloodstream infections (CRBSI). The National Quality Forum (NQF) (2010) identified CRBSIs as one of their endorsed patient safety measures that health care institutions are encouraged to report. Beginning in October of 2008, the Centers for Medicare and Medicaid Services (CMS) no longer reimburses over and above the typical inpatient prospective payment system rate for care required to manage and correct a CRBSI. This means that a hospital is not paid for the added costs and hospital days needed to treat it. Nurses require specialized education regarding care of central venous catheters and implanted infusion ports. Nursing responsibilities for central lines include careful monitoring, flushing to keep the line patent, and site care and dressing changes to prevent CRBSIs.

Initiating the Intravenous Line: After you collect the equipment at the patient’s bedside, prepare to insert the IV line by assessing the patient for a venipuncture site (see Skill 41-1). The most common IV sites are on the inner arm (Fig. 41-15). Do not use hand veins on older adults or ambulatory patients. IV insertion in a foot vein is common with children, but avoid these sites in adults because of the increased risk of thrombophlebitis (INS, 2011).

As you assess a patient for potential venipuncture sites, consider conditions that exclude certain sites. Venipuncture is contraindicated in a site that has signs of infection, infiltration, or thrombosis. An infected site is red, tender, swollen, and possibly warm to the touch. Exudate may be present. Do not use an infected site because of the danger of introducing bacteria from the skin surface into the bloodstream. Avoid using an extremity with a vascular (dialysis) graft/fistula or on the same side as a mastectomy. Avoid areas of flexion if possible (INS, 2011). Choose the most distal appropriate site (INS, 2011). Using a distal site first allows for the use of proximal sites later if the patient needs a venipuncture site change.

Venipuncture is a technique in which a vein is punctured through the skin by a sharp rigid stylet (e.g., metal needle). The stylet is partially covered either with a plastic catheter or a needle attached to a syringe. General purposes of venipuncture are to collect a blood specimen, start an IV infusion, provide vascular access for later use, instill a medication, or inject a radiopaque or other tracer for special diagnostic examinations. Skill 41-1 describes venipuncture for peripheral IV fluid infusion, incorporating INS (2011) standards of practice. It takes practice to become proficient in venipuncture. Only experienced practitioners perform it for patients whose veins are fragile or collapse easily, such as older adults. Box 41-6 describes principles to follow for venipuncture in older adults.

Nurses require specialized knowledge and education to place PICCs. Some central lines and implanted ports require insertion by physicians or advanced practice nurses. Both types of central catheters require close monitoring and maintenance. This chapter focuses on peripheral catheters.

Regulating the Infusion Flow Rate: After initiating a peripheral IV infusion and checking it for patency, regulate the rate of infusion according to the health care provider’s orders (Skill 41-2 on pp. 925-929). For patient safety avoid uncontrolled flow of IV fluid into a patient. You are responsible for calculating the flow rate per hour that delivers the IV fluid in the prescribed time frame. The correct IV infusion rate ensures patient safety by preventing too-slow or too-rapid administration of IV fluids. An infusion rate that is too slow often leads to further physiological compromise in a patient who is dehydrated, in circulatory shock, or critically ill. An infusion rate that is too rapid overloads the patient with IV fluid, causing fluid and electrolyte imbalances and cardiac complications in vulnerable patients (e.g., older adults or patients with preexisting heart disease).

Electronic infusion devices (EIDs), also called IV pumps or infusion pumps, deliver an accurate hourly IV infusion rate. EIDs use positive pressure to deliver a measured amount of fluid during a specified unit of time (e.g., 125 mL/hr). Familiarize yourself with the brand of EID in use at your agency so you are able to accurately set the flow rate. Many EIDs have capabilities that allow for single- and multiple-solution infusions at different rates. A variety of electronic detectors and alarms respond to air in IV lines, occlusion, completion of infusion, high and low pressure, and low battery power.

When you open a roller clamp or other type of clamp on an infusion tubing that is not yet properly inserted in an EID or on a gravity-flow IV system, the IV fluid infuses very rapidly. Nonelectronic volume control devices are used occasionally with an IV solution infused by gravity to prevent accidental infusion of a large fluid volume. These devices hang between the IV bag and the patient and hold only a small volume of fluid that can infuse into the patient. Regardless of the device in use, monitor the patient regularly to verify correct infusion of IV fluids. Patency of an IV catheter means that IV fluid flows easily through it. For patency there must be no clots at the tip of the catheter, and the catheter tip must not be against the vein wall. A blocked catheter slows or stops the rate of infusion of the IV fluids. IV flow rate also can be slowed by infiltration, vasospasm, a knot or kink in the tubing, external pressure on the tubing, and position changes of the patient’s extremity. If the flow decreases or stops and the EID is working correctly, inspect the tubing. Sometimes the patient is lying or sitting on it. Also inspect the area around the insertion site for anything that obstructs the flow of IV fluids. For gravity flow, the height of the container influences flow rate. Raising the container usually increases the rate because of increased driving pressure.

Flexion of an extremity, particularly at the wrist or elbow, can decrease IV flow rate by compressing the vein. Although VAD placement in areas of flexion is discouraged, occasionally it becomes necessary. In that case INS standards specify use of an arm board or other joint stabilization device to protect the IV site by keeping the joint extended (INS, 2011). Use padding with arm boards because they may cause skin or nerve damage from pressure. Starting an infusion in a new location rather than relying on a site that causes problems may be more comfortable for a patient. Before discontinuing the current infusion, choose another site and start the infusion to verify that the patient has other accessible veins.

Maintaining the System: After placing an IV line and regulating the flow rate, maintain the IV system. Line maintenance involves (1) keeping the system sterile and intact; (2) changing IV fluid containers, tubing, and contaminated site dressings; (3) assisting a patient with self-care activities so as not to disrupt the system; and (4) monitoring for complications of IV therapy. The frequency and options for maintaining the system are identified in agency policies.

An important component of patient care is maintaining the integrity of an IV line to prevent infection. Potential sites for contamination of a VAD are shown in Fig. 41-16. Inserting an IV line under appropriate aseptic technique reduces the chances of contamination from the patient’s skin microflora. After insertion the conscientious use of infection control principles, including thorough hand hygiene before and after handling any part of the IV system and maintaining sterility of the system during tubing and fluid container changes, prevents infection.

Always maintain the integrity of an IV system. Never disconnect tubing because it becomes tangled or it might seem more convenient for positioning or moving a patient or applying a gown. If a patient needs more room to maneuver, use aseptic technique to add extension tubing to an IV line. However, keep the use of extension tubing to a minimum, because each connection of tubing provides opportunity for contamination. Never let IV tubing touch the floor. You do not use stopcocks for connecting more than one solution to a single IV site because they are sources of contamination (CDC, 2002; INS, 2011). IV tubing contains needleless injection ports through which syringes or other adaptors can be inserted for medication administration. Clean an injection port thoroughly with 2% chlorhexidine (preferred), 70% alcohol, or povidone-iodine solution and let it dry before accessing the system (INS, 2011).

Protective devices designed to prevent movement or accidental dislodgment of a VAD are called catheter stabilization devices (Fig. 41-17). These devices are available in many hospitals, and nurses decide whether or not to use them when starting an IV line (Box 41-7). This is a patient safety issue. INS standards indicate that use of these devices is preferable over taping when feasible (INS, 2011).

Changing Intravenous Fluid Containers, Tubing, and Dressings: Patients receiving IV therapy over several days require periodic changes of IV fluid containers (Skill 41-3 on pp. 929-934). It is important to organize tasks so you can change containers rapidly before a thrombus forms in the catheter.

Recommended frequency of IV tubing change depends on whether it is used for continuous or intermittent infusion. INS (2011) standards specify that continuous infusion tubing changes occur no more frequently than every 96 hours unless the tubing has been compromised or has become contaminated, which requires immediate tubing change. In contrast, change tubing for intermittent infusion every 24 hours because of the increased risk of contamination from opening the IV system (INS, 2011). Blood, blood components, and lipids are likely to promote bacterial growth in tubing. INS standards (2011) specify tubing changes every 4 hours for blood and blood components and every 24 hours for continuous IV lipids. For lipids use tubing that is free of diethylhexyl-phthalate (DEHP), a toxin that leaches into lipid solutions (INS, 2011). Whenever possible, schedule tubing changes when it is time to hang a new IV container to decrease risk of infection (INS, 2011). To prevent entry of bacteria into the bloodstream, maintain sterility during tubing and IV fluid container changes (INS, 2011).

A sterile dressing over an IV site reduces the entrance of bacteria into the insertion site. Transparent dressings, the most common type, help secure the VAD, allow continuous visual inspection of the IV site, and become less easily soiled or moistened than gauze dressings. You leave transparent dressings in place until the IV tubing is replaced (INS, 2011). If a gauze dressing is used, change it every 48 hours (INS, 2011). Both types of dressings must be changed when the IV device is removed or replaced or when the dressing becomes damp, loosened, or soiled (INS, 2011) (Skill 41-4 on pp. 934-936).

Complications of Intravenous Therapy: Table 41-12 presents complications of IV therapy, with assessments and nursing interventions. A potentially dangerous complication of IV therapy is circulatory overload with IV solution, which occurs when a patient receives too-rapid administration or an excessive amount of fluids. Assessment findings depend on the type of IV solution that infuses in excess (see Table 41-12). The signs and symptoms often arise rapidly, which highlights the importance of frequent assessment of patients receiving IV therapy.

Infiltration occurs when an IV catheter becomes dislodged or a vein ruptures and IV fluids inadvertently enter subcutaneous tissue around the venipuncture site. When the IV fluid contains additives that damage tissue, extravasation occurs (Hadaway, 2007). Infiltration or extravasation causes coolness, paleness, and swelling of the area. When infiltration occurs, immediately assess for any additives in the infiltrated fluid to determine what type of action is necessary to prevent local tissue damage and sloughing. Vasoconstrictors, high-dose potassium, and other IV additives in subcutaneous tissue need different treatments from those needed for an infiltrated additive-free IV (Doellman et al., 2009) (see Table 41-12). Although the INS removed their previous infiltration scale from their 2011 standards because of insufficient research validation, the society does recommend use of an infiltration scale to provide objectivity in infiltration measurement (Table 41-13).

Phlebitis (i.e., inflammation of a vein) results from chemical, mechanical, or bacterial causes. Risk factors for phlebitis include acidic or hypertonic IV solutions; rapid IV rate; IV drugs such as KCl, vancomycin, and penicillin; VAD inserted in area of flexion, poorly secured catheter; poor hand hygiene; and lack of aseptic technique (Roszell and Jones, 2010). The typical signs of inflammation (i.e., heat, erythema [redness], tenderness) occur along the course of the vein (Table 41-14). Phlebitis can be dangerous because blood clots (thrombophlebitis) form along the vein and in some cases cause emboli. This may cause permanent damage to veins. Although some agencies require routine removal of VADs and site rotation to help prevent phlebitis and other complications, the INS Standards of Practice (2011) recommend replacement of a peripheral IV catheter only if clinically indicated in adults (Webster et al., 2010). Avoid routine replacement of peripheral IV catheters in infants and children (INS, 2011).

In the absence of phlebitis, local infection at the venipuncture site is usually caused by poor aseptic technique during catheter insertion, daily monitoring, or catheter removal. Early recognition of local infection and treatment are important to prevent bacteria from entering the bloodstream (see Table 41-12).

Bleeding can occur around the venipuncture site during the infusion or through the catheter or tubing if these become disconnected inadvertently (see Table 41-12). Bleeding is more common in patients who receive heparin or other anticoagulants or who have a bleeding disorder (e.g., hemophilia or thrombocytopenia).

Discontinuing Peripheral Intravenous Access: Discontinue IV access after infusion of the prescribed amount of fluid; when infiltration, phlebitis, or local infection occurs; or if the IV catheter develops a thrombus at its tip. Skill 41-3 presents the steps for discontinuing peripheral IV access. You help patients and families understand that moving from IV infusion to oral fluid intake is a sign of progress toward recovery.

Blood Transfusion: Blood transfusion, or blood component therapy, is the IV administration of whole blood or a blood component such as packed red blood cells (RBCs), platelets, or plasma. Objectives for administering blood transfusions include (1) increasing circulating blood volume after surgery, trauma, or hemorrhage; (2) increasing the number of RBCs and maintaining hemoglobin levels in patients with severe anemia; and (3) providing selected cellular components as replacement therapy (e.g., clotting factors, platelets, albumin).

Interventions for Electrolyte Imbalances: In addition to the administration of prescribed medical therapies, there are nursing interventions for preserving or restoring electrolyte imbalance. For example, people who have hypokalemia or hypercalcemia often need bowel management for constipation. Patient safety interventions to prevent falls (see Chapter 27) are vital for patients who become lethargic from hypercalcemia and those with muscle weakness. Patients who have hypercalcemia need an increased fluid intake to prevent renal damage; nurses can help them meet the oral fluid intake goals. Teach patients the reasons for their therapies and the importance of balancing electrolyte I&O to prevent imbalances in the future.

Interventions for Acid-Base Imbalances: Nursing interventions to promote acid-base balance support prescribed medical therapies and aim at reversing the existing acid-base imbalance while providing for patient safety. when imbalances are life threatening, they require rapid treatment. Maintain a functional IV line and check the health care provider’s orders frequently for new medications or fluids. Give fluid and electrolyte replacement and prescribed drugs such as insulin promptly. In addition, monitor patients closely for changes in their status. Use protective measures such as side rails for patients with decreased level of consciousness. Support compensatory hyperventilation for patients with metabolic acidosis by keeping their oral mucous membranes moist and positioning them to facilitate chest expansion. Chapter 40 reviews appropriate therapies for patients with respiratory acidosis. Patients with acid-base imbalances often require repeated ABG analysis.

Home Intravenous Therapy: IV therapy often continues in the home setting for patients requiring long-term hydration, PN, or long-term medication administration. A home IV therapy nurse works closely with the patient to ensure that a sterile IV system is maintained and complications can be avoided or recognized promptly. Box 41-8 summarizes patient education guidelines for home IV therapy.

Nutritional Support: Most patients who have had electrolyte disorders or metabolic acid-base imbalances require ongoing nutritional support. Depending on the type of disorder, fluid or food intake may be encouraged or restricted (see Chapter 44). Patients or family members who are responsible for meal preparation need to learn to understand nutritional content of foods and read the labels of commercially prepared foods.

Medication Safety: Numerous medications, OTC drugs, and herbal preparations contain components or create potential side effects that can alter fluid and electrolyte balance. Patients with chronic disease who are receiving multiple medications and those with renal disorders are at significant risk for alterations. Once patients return to a restorative care setting, whether in the home, long-term care, or other setting, drug safety is very important. Patient and family education regarding potential side effects and drug interactions that can alter fluid, electrolyte, or acid-base balance is essential. Review all medications with patients, and encourage them to consult with their local pharmacist, especially if they wish to try a new OTC drug or herbal preparation.

• “What difficulties are you having with measuring your I&O daily and keeping a record?”

• “What barriers are you experiencing to obtaining the potassium-rich foods you need?”

• “Are you continuing to have frequent loose stools or diarrhea?”

• “Have you purchased an antacid, or are you still using baking soda as an antacid?”

1. Why is Mrs. Beck likely becoming light-headed? When should you expect this to resolve?

2. Mrs. Beck’s IV fluid order is 1000 mL 0.9% sodium chloride to run over 8 hours. Calculate the milliliters per hour that you should program into her infusion pump.

3. you auscultate crackles in Mrs. Beck’s lung bases while her IV is infusing. What is your next action?

1. A patient who is comatose is admitted to the hospital with an unknown history. Respirations are deep and rapid. Arterial blood gas levels on admission are pH, 7.20; PaCO₂, 21 mm Hg; PaO₂, 92 mm Hg; and , 8. You interpret these laboratory values to indicate:

2. A patient with a cardiac history is taking the diuretic furosemide (Lasix) and is seen in the emergency department for muscle weakness. which laboratory value do you assess first?

3. Which of these patients do you expect will need teaching regarding dietary sodium restriction?

4. You teach patients to replace sweat, vomiting, or diarrhea fluid losses with which type of fluid?

5. You assess four patients. Which patient is at greatest risk for the development of hypocalcemia?

6. Which of the following activities can you delegate to nursing assistive personnel (NAP)? (Select all that apply.)

7. Place the following steps for intravenous (IV) catheter insertion in the correct order:

8. Assessment findings consistent with intravenous (IV) fluid infiltration include: (Select all that apply.)

9. Which of the following defining characteristics is consistent with fluid volume deficit?

    10. Which of the following assessments do you perform routinely when an older adult patient is receiving intravenous 0.9% NaCl?

    11. While receiving a blood transfusion, your patient develops chills, tachycardia, and flushing. What is your priority action?

    12. The health care provider’s order is 1000 mL 0.9% NaCl with 20 mEq K⁺ intravenously over 8 hours. Which assessment finding causes you to clarify the order with the health care provider before hanging this fluid?

    13. Your patient who has diabetic ketoacidosis is breathing rapidly and deeply. Intravenous (IV) fluids and other treatments have just been started. What should you do about this patient’s breathing?

    14. Your patient had 200 mL of ice chips and 900 mL intravenous (IV) fluid during your shift. Which total intake should you record?

    15. The health care provider’s order is 1000 mL 0.9% NaCl IV over 6 hours. Which rate do you program into the infusion pump?