Fluid Volume Disturbance PDF

11/27/23, 4:31 AM Realizeit for Student Fluid Volume Disturbance Clinical Manifestations FVD can develop rapidly, and its severity depends on the degree of fluid loss. Clinical signs and symptoms and laboratory findings are presented in Table 10-4. Assessment and Diagnostic Findings Laboratory da...

11/27/23, 4:31 AM Realizeit for Student Fluid Volume Disturbance Clinical Manifestations FVD can develop rapidly, and its severity depends on the degree of fluid loss. Clinical signs and symptoms and laboratory findings are presented in Table 10-4. Assessment and Diagnostic Findings Laboratory data used to evaluate fluid volume status include BUN and its relation to serum creatinine concentration. Normal BUN to serum creatinine concentration ratio is 10:1. A volumedepleted patient has a BUN elevated out of proportion to the serum creatinine (ratio greater than 20:1) because urea becomes concentrated in FVD (Sterns, 2017a). The presence and cause of hypovolemia may be determined through the health history and physical examination. In addition, the hematocrit level is greater than normal because there is a decreased plasma volume, which concentrates the volume of RBCs. Serum electrolyte changes may also exist. Potassium and sodium levels can be reduced (hypokalemia, hyponatremia) or elevated (hyperkalemia, hypernatremia). Hypokalemia can occur with GI and renal losses as these organs are major regulators of potassium. Hyperkalemia can occur with adrenal insufficiency due to aldosterone deficiency which causes lack of potassium excretion. Hyponatremia can occur with increased thirst and ADH release, which increases water content of the bloodstream. Hypernatremia can result from increased insensible water losses and diabetes insipidus. Oliguria, the excretion of less than 400 mL urine per day in the adult, may or may not be present in hypovolemia. Urine specific gravity will change in relation to the kidneys’ attempt to conserve water. If the kidney does not reabsorb water, urine contains more water, and urine specific gravity is low. If the kidney does reabsorb water, urine will be concentrated and specific gravity increases. Due to lack of ADH in diabetes insipidus, urine water content increases, which decreases urine specific gravity. Aldosterone is secreted when fluid volume is low, causing reabsorption of sodium and chloride and resulting in decreased urinary sodium and chloride. When the kidneys conserve water, urine osmolality can increase to greater than 450 mOsm/kg and urine specific gravity increases (Sterns, 2017a). https://herzing.realizeithome.com/RealizeitApp/Student.aspx?Token=0Dn26kXyU%2f6F5gOCz4%2f2IZsc2gfB3djkaGXwQ9ctgb2A3gz%2bCKrCW4cKwIi8CIqb… 1/6 11/27/23, 4:31 AM Realizeit for Student Gerontologic Considerations Increased sensitivity to fluid and electrolyte changes in older patients requires careful physical assessment, measurement of I&O of fluids from all sources, assessment of daily weight, careful monitoring of side effects and interactions of medications, and prompt reporting and management of disturbances. In most adult patients, it is useful to monitor skin turgor to detect subtle changes. However, assessment of skin turgor is not as valid in older adults because the skin has lost elasticity; therefore, other assessment measures (e.g., slowness in filling of veins of the hands and feet) become more useful in detecting FVD (Cash & Glass, 2018; Weber & Kelley, 2018). The nurse also performs a functional assessment of the older patient’s ability to determine fluid and food needs and to obtain adequate intake in addition to assessments discussed earlier in this module. For example, the nurse assesses whether or not the patient is cognitively intact, able to ambulate and to use both arms and hands to reach fluids and foods, and able to swallow with an intact gag reflex. Results of this functional assessment have a direct bearing on how the patient will be able to meet their own need for fluids and foods (Weber & Kelley, 2018). During an older patient’s hospital stay, the nurse provides fluids if the patient is unable to carry out selfcare activities. The nurse should also recognize that some older patients deliberately restrict their fluid intake to avoid episodes of urinary incontinence. In this situation, the nurse should identify interventions to deal with the incontinence, such as encouraging the patient to wear protective clothing or https://herzing.realizeithome.com/RealizeitApp/Student.aspx?Token=0Dn26kXyU%2f6F5gOCz4%2f2IZsc2gfB3djkaGXwQ9ctgb2A3gz%2bCKrCW4cKwIi8CIqb… 2/6 11/27/23, 4:31 AM Realizeit for Student devices, to carry a urinal in the car, or to pace fluid intake to allow access to toilet facilities during the day. Older adults without cardiovascular or renal dysfunction should be reminded to drink adequate fluids, particularly in very warm or humid weather (Cash & Glass, 2018). Medical Management When planning the correction of fluid loss for the patient with FVD, the primary provider considers the patient’s maintenance requirements and other factors (e.g., fever) that can influence fluid needs. If the deficit is not severe, the oral route is preferred, provided the patient can drink. However, if fluid losses are acute or severe, the IV route is required. Isotonic electrolyte crystalloid solutions (e.g., lactated Ringer’s solution or 0.9% sodium chloride) are frequently the first-line choice to treat the hypotensive patient with FVD because they expand plasma volume. As soon as the patient becomes normotensive, a hypotonic electrolyte solution (e.g., 0.45% sodium chloride) is often used to provide both electrolytes and water for renal excretion of metabolic wastes (Sterns, 2017a; Sterns, 2017b). Accurate and frequent assessments of I&O, weight, vital signs, central venous pressure, level of consciousness, breath sounds, and skin color are monitored to determine when therapy should be slowed to avoid volume overload. The rate of fluid administration is based on the severity of loss and the patient’s hemodynamic response to volume replacement (Sterns, 2017a; Sterns, 2017b). If the patient with severe FVD is not excreting enough urine and is therefore oliguric, the primary provider needs to determine whether the depressed renal function is caused by reduced renal blood flow secondary to FVD (prerenal azotemia) or, more seriously, by acute tubular necrosis (intrarenal azotemia) from prolonged FVD (Norris, 2019). The test used in this situation is referred to as a fluid challenge test. During a fluid challenge test, volumes of fluid are given at specific rates and intervals while the patient’s hemodynamic response to this treatment is monitored (i.e., vital signs, breath sounds, orientation status, central venous pressure, urine output) (Sterns, 2017b). An example of a typical fluid challenge test involves administering 100 to 200 mL of normal saline solution over 15 minutes. The goal is to provide fluids rapidly enough to attain adequate tissue perfusion without compromising the cardiovascular system. The response by a patient with FVD but normal renal function is increased urine output and an increase in blood pressure and central venous pressure. Shock can occur when the volume of fluid lost exceeds 25% of the intravascular volume or when fluid loss is rapid (Mandel & Palevsky, 2019). https://herzing.realizeithome.com/RealizeitApp/Student.aspx?Token=0Dn26kXyU%2f6F5gOCz4%2f2IZsc2gfB3djkaGXwQ9ctgb2A3gz%2bCKrCW4cKwIi8CIqb… 3/6 11/27/23, 4:31 AM Realizeit for Student Clinical Manifestations Clinical manifestations of FVE result from expansion of the ECF and may include edema, distended jugular veins, and crackles (abnormal lung sounds due to interstitial pulmonary fluid). In patients who are ambulatory, edema is most evident in the ankles; in patients who are supine, edema occurs over the sacrum (Weber & Kelley, 2018). Further discussion of clinical signs and symptoms and laboratory findings can be found in Table 10-4. Assessment and Diagnostic Findings Laboratory data useful in diagnosing FVE include BUN and hematocrit levels. In FVE, both of these values may be decreased because of plasma dilution. In chronic kidney disease, both serum osmolality and the sodium level are decreased due to excessive retention of water. The urine sodium level is increased if the kidneys are attempting to excrete excess volume. A chest x-ray may reveal pulmonary congestion in FVE. Hypervolemia occurs when aldosterone is chronically stimulated—for example, in conditions such as cirrhosis, heart failure, and nephrotic syndrome. Aldosterone increases both sodium and water reabsorption into the bloodstream from the nephron; therefore, the urine sodium level is normal in these conditions (Emmett & Palmer, 2019; Sterns, 2018a). Medical Management https://herzing.realizeithome.com/RealizeitApp/Student.aspx?Token=0Dn26kXyU%2f6F5gOCz4%2f2IZsc2gfB3djkaGXwQ9ctgb2A3gz%2bCKrCW4cKwIi8CIqb… 4/6 11/27/23, 4:31 AM Realizeit for Student Management of FVE is directed at the causes, and if related to excessive administration of sodium-containing fluids, discontinuing the infusion may be all that is needed. Symptomatic treatment consists of administering diuretics and restricting fluids and sodium. Diuretics are medications that reduce sodium and water reabsorption at the nephron and thereby enhance water loss via the kidneys (Brater & Ellison, 2019). Pharmacologic Therapy Diuretics are prescribed when dietary restriction of sodium alone is insufficient to reduce edema. The choice of diuretic is based on the severity of the hypervolemic state, the degree of impairment of renal function, and the potency of the diuretic. Thiazide diuretics block sodium and water reabsorption into the bloodstream at the distal tubule of the nephron, where 5% to 10% of sodium is normally reabsorbed. This leads to a small amount of sodium and water loss via the urine. Loop diuretics, such as furosemide, bumetanide, or torsemide, can cause a greater loss of both sodium and water because they block sodium reabsorption in the ascending limb of the loop of Henle, where 20% to 30% of filtered sodium is normally reabsorbed. Generally, thiazide diuretics, such as hydrochlorothiazide, are prescribed for mild to moderate hypervolemia and loop diuretics for severe hypervolemia (Brater & Ellison, 2019). Electrolyte imbalances may result from side effects of diuretics. Hypokalemia can occur with all diuretics except those that inhibit aldosterone. Potassium supplements can be prescribed with diuretics to avoid this complication. Hyperkalemia can occur with diuretics that inhibit aldosterone (e.g., spironolactone, a potassium-sparing diuretic), especially in patients with decreased renal function. Hyponatremia occurs with diuresis due to increased release of ADH secondary to reduction in circulating volume. Decreased magnesium levels occur with administration of loop and thiazide diuretics due to decreased reabsorption and increased excretion of magnesium by the kidney (Brater & Ellison, 2019; Vallerand & Sanoski, 2019). Azotemia (increased nitrogen levels in the blood) can occur with FVE when urea and creatinine are not excreted due to decreased perfusion by the kidneys and decreased excretion of waste, as occurs in renal failure. High uric acid levels (hyperuricemia) can also occur from increased reabsorption and decreased excretion of uric acid by the kidneys. Dialysis If renal function is so severely impaired that pharmacologic agents cannot act efficiently, other modalities are considered to remove sodium and fluid from the body. Hemodialysis or peritoneal dialysis may be used to remove nitrogenous wastes and control potassium and acid–base balance, and to remove sodium and fluid. Continuous renal replacement therapy may also be required. https://herzing.realizeithome.com/RealizeitApp/Student.aspx?Token=0Dn26kXyU%2f6F5gOCz4%2f2IZsc2gfB3djkaGXwQ9ctgb2A3gz%2bCKrCW4cKwIi8CIqb… 5/6 11/27/23, 4:31 AM Realizeit for Student Nutritional Therapy Treatment of FVE usually involves dietary restriction of sodium. An average daily diet not restricted in sodium contains 6 to 15 g of salt, whereas low sodium diets can range from a mild restriction (less than 2000 mg/day) to as little as 250 mg of sodium per day, depending on the patient’s needs. A mild sodium-restricted diet allows only light salting of food (about half the usual amount) in cooking and at the table, and no addition of salt to commercially prepared foods that are already seasoned. Foods high in sodium must be avoided. It is the sodium salt (sodium chloride) rather than sodium itself that contributes to edema. Therefore, patients are instructed to read food labels carefully to determine salt content (Olendzki, 2017). Because about half of ingested sodium is in the form of seasoning, seasoning substitutes can play a major role in decreasing sodium intake. Lemon juice, onions, and garlic are excellent substitute flavorings, although some patients prefer salt substitutes. Most salt substitutes contain potassium and must therefore be used cautiously by patients taking potassium-sparing diuretics (e.g., spironolactone, triamterene, amiloride). These substitutes should not be used in conditions associated with potassium retention, such as advanced kidney disease. Salt substitutes containing ammonium chloride can be harmful to patients with liver damage (Olendzki, 2017; Vallerand & Sanoski, 2019). In some communities, drinking water may contain too much sodium for a sodium-restricted diet. Depending on its source, water may contain as little as 1 mg or more than 1500 mg of sodium per quart. Patients may need to use distilled water if the local water supply is very high in sodium. Bottled water can have a sodium content that ranges from 0 to 1200 mg/L; therefore, if sodium is restricted, the label must be carefully examined for sodium content before purchasing and drinking bottled water. Also, patients on sodium-restricted diets should be cautioned to avoid water softeners that add sodium to water in exchange for other ions, such as calcium. Protein intake may be increased in patients who are malnourished or who have low serum protein levels in an effort to increase capillary oncotic pressure. Increasing oncotic pressure in the bloodstream will pull fluid out of the tissues into vessels for excretion by the kidneys (Sterns, 2018a). https://herzing.realizeithome.com/RealizeitApp/Student.aspx?Token=0Dn26kXyU%2f6F5gOCz4%2f2IZsc2gfB3djkaGXwQ9ctgb2A3gz%2bCKrCW4cKwIi8CIqb… 6/6