Chapter 41 – Fluid, Electrolyte, and Acid-base Balance

body fluid contains
electrolytes
Electrolytes are
sodium and potassium
electrolyte contains what types of compound? what does the compound do?
contains cation and anion, when they combine, they make salt.
sodium and potassium has a degree of
acidity
what maintain the health and function of all body systems?
fluid, electrolyte, and acid -base balances within the body
what has an effect on the cell function?
characteristic of body fluid influence cell function
characteristic of cell functions are
fluid amount, concentration, composition,, and degree of acidity
Fluid amount is
volume
concentration is
osmolarity
composition
electrolyte concentration
degree of acidity is
pH
fluid means
water that contains dissolved or suspended substances such as glucose, mineral salts, and proteins.
Fluid compartments
Intracellular Fluid (28L) – Cell membrane- Interstitial fluid (11L) – Capillary membrane – Intravascular plasma (3L)

Graph from bottom to top.

Extracellular Fluid (ECF) are
Interstitial fluid (11L) and Intravascular plasma (3L) and a minor division (trans-cellular fluid).
Intravascular fluid is ?
plasma
Interstitial fluid is located
between the cell and outside the blood vessels.
Transcullar fluid are and secrete by ?
They are cerebrospinal, pleural, peritoneal, and synovial fluids.

They are secreted by epithelial cells.

mEq = ?
mg of one electrolyte + mg of another electrolyte
mMol =?
#of mg of electrolyte / molecular weight that are contain ed in a liter of the fluid being measured (usually blood plasma or serum).
osmolality of a fluid
is a measure of the number of particles per kg of water
what determine tonicity of a fluid
the particles that cannot cross cell membranes easily.
isotonic solution
a fluid with the same concentration of nonpermeant particles as normal blood
hypotonic solution
more dilute than normal blood
hypertonic solution
more concentrated than normal blood.
Sodium (Na+) normal value in serum or blood
136-145 mMol/L
Normal Value in Serum or Blood – Potassium (K+)
3.5-5.0 mEq/L
normal value in serum or blood – Chlorde (Cl-)
98-106 mEq/L
Normal Value in Serum or blood – Total CO2
22-30 mEq/L
Normal Value in Serum or Blood – Bicarbonate (HCO3-)
Arterial 22-26mEq/L, Venous 24-30 mEq/L
Normal Value in Serum or Blood – Total Calcium (Ca2+)
8.4-10.5mg/dL
Normal value in Serum or Blood – Ionized calcium
4.5-5.3 mg/dL
Normal Value in serum or blood – Magnesium (Mg2+)
1.5-2.5 mEq /L
Normal value in serum or blood – phosphate
2.7-4.5 mg/dL
normal value in serum or blood – anion gap
5-11 mEq/L
Normal Value in Serum or blood , Arterial Blood Gases – pH
7.35-7.45
Normal value in serum or blood, arterial blood gases, PaCO2
35-45 mm Hg
Normal Value in Serum or Blood, Arterial Blood Gases, PaO2
80-100mm Hg
Normal Value in Serum or Blood, Arterial Blood Gases, O2 Saturation
95-100%
Normal value in Serum or Blood, Arterial Blood Gases, Base Excess
-2 to +2 mmol/L
Movement of Water and Electrolytes require three types of transport, they are?
1. active transport.
2. Diffusion.
3. Osmosis.
Movement of water and electrolyte – active transport
this transport requires energy in the form of ATP to move electrolyte across cell membranes against the concentration gradient (from lower to higher concentration area) – think about walking up the hill, spend more energy
Movement of water and electrolyte – diffusion
Passive movement of electrolytes or other particles down the concentration gradient. this process requires proteins that serve as ion channels.
Example of diffusion?
muscle and nerve function require ion channels
Movement of water and electrolyte – osmosis
water move through a membrane via osmosis
Osmotic pressure
an inward-pulling force caused by particles in the fluid
What is inward -pulling force
water moves into the compartment that has a higher osmotic pressure until the particle concentration is equal in two compartments.
Movement of water and electrolyte – Example of osmosis
Hypotonic solution administer into the body, more water goes into the cell.

Hypertonic solution administer into the body, more water leave the cell.

Movement of water and electrolytes – filtration
a process that fluid moves into and out of capillaries (between vascular and interstitial compartments)
What are the net effect of forces for filtration?
2 tend to move fluid out of capillaries and small venules and two that tend to move fluid back into them.
Filtration – Hydrostatic pressure
is the force of the fluid pressing outward against a surface

Ex. capillary has stronger hydrostatic pressure, so it pushes fluid outward to interstitial, but interstitial fluid hydrostatic pressure is weaker opposing force, so it tends to push fluid back into capillaries.

Movement of water and Electrolyte – Colloids
proteins that are much larger than electrolyte,glucose, and other molecules that dissolve easily.
Movement of water and electrolytes – colloid osmotic pressure
aka oncotic pressure, an inward pulling force caused by blood proteins that helps move fluid from the interstitial area back into capillaries.

* note: colloid osmotic pressure normally is very small opposing force (not significant? )

Movement of water and electrolyte – Hydrostatic pressure is weaker in? Colloid osmotic pressure is stronger ?
at the venous end capillary , hydrostatic pressure is weaker, but colloid osmotic pressure in the blood is stronger. So fluid move into capillary at the venous end
Movement of water and electrolyte – strongest hydrostatic pressure? Colloid osmotic pressure weaker?
Arterial end of the capillary, the capillary hydrostatic pressure is strongest. Fluid moves from capillary into interstitial area, bringing nutrients to cells.
Movement of water and electrolyte – endema
accumulation of excessive fluid in the interstitial space. This can be caused by a disease processes and other factors alter these forces.
Fluid Balance – Fluid homeostasis requires interplay of the three process, they are ?
fluid intake and absorption, fluid distribution, and fluid output.
Fluid Balance – average fluid intake for healthy adult
is about 2300 mL
Fluid Balance – who are at risk of dehydration ?
infants, patients with neurological or psychological problems, and some older adults who are unable to perceive or communicate their thirst.
Fluid balance – Physiological factors
– the thirst controlled mechanism is located within the hypothalamus in the brain.

– conscious is an important regulator of fluid intake, when the plasma osmolality increases (osmoreceptor -mediated thirst) or the blood volume decrease (baroreceptor -mediated thirst and angiotensin II – and III – mediated thrist)

Fluid Balance, Fluid Intake mechanisms , Fig 41-5 Stimuli affecting thirst mechanism
– increase plasma osmolality
– decrease plasma volume
– angiotensin II and III
– Dry pharyngeal mucous membranes
– Psychological factors
Fluid balance – fluid distribution
movement of fluid among its various compartments.

Example:
. osmosis – Extracellular and intracellular compartments occur
. Filtration – between the vascular and interstitial portion of the ECF.

Fluid Balance – Fluid Output normally occur in which four organs?
Skin, Lung, GI, and kidney.
Fluid Balance – Fluid output, which organ is the major regulator of fluid output? why?
Kidney , they response to hormones that influence urine production.
Fluid Balance – Fluid output, Antidiuretic hormone (a) where does it releasee from? (b) what does it do? (c) What happen to urine output and blood volume?
The hormone regulates the osmolality of the body fluid by influencing how much water is excreted in urine.

Hypothalamus release it from posterior pituitary gland.

When it circulate to the blood, it acts on the collecting ducts -> renal cells to resorb water, taking water from the renal tubular fluid and put it back in the blood.

Urine volume decreased, concentrating the urine while diluting the blood by adding water to it.

Fluid Balance – Fluid Output, Renin-Angiotensin-Aldosterone System.
RAAS regulates ECF volume by influencing how much sodium and water are excreted in urine.

Blood volume decrease -> Renin (enzyme) -> angiotensin -> Angiotensin II -> Aldosterone (adrenal Cortex) -> absorb water and sodium back -> Extracellular Fluid Volume -> increase excretion of potassium and hydrogen ion.

Fluid balance – Fluid output, Atrial Natriuretic Peptide
ANP release by the cells in the atria of the heart when they stretch.

ANP regulate ECV by influencing how much sodium and water are excreted in urine.

ANP (weak hormone) inhibits ADH by releasing the loss of sodium and water into the urine, so ANP opposes the effect of aldosterone.

Fluid Imbalance – two types
. volume imbalance
. osmolality imbalance
Fluid Imbalance – Volume Imbalance
Disturbances of the amount of fluid in the extracellular compartment.
Fluid Imbalance – Osmolality Imbalance
disturbance of concentration of body fluids
Does volume and osmolality imbalance occur together?
either separately or together
Fluid Imbalance – ECV deficit
is present when there is insufficient isotonic fluid in the extracellular compartment.
Fluid Imbalance – Hypovolemia
decreased vascular volume
Fluid Imbalance – Extracellular Fluid Volume Imbalance, ECV excessive
too much isotonic fluid in the extracellular compartment
Fluid Imbalance – Osmolality Imbalance causes body fluid to be ?
. Hypertonic
. Hypotonic
Fluid Imbalance – Osmolality Imbalances, Hypernatremia
called water deficit, in a hypertonic condition, water leave cells by osmosis
Fluid Imbalance – Osmolality Imbalance, Hypernatremia, signs and symptoms?
when brain cells shrivels, or clinical dehydration
Fluid Imbalance – Osmolality Imbalance, Hyponatremia
water excess or water intoxication, is a hypotonic condition, excessive water leave cell cause cell to swell.
Fluid Imbalance – Osmolality Imbalance, Hyponatremia, signs and symptoms ?
Cerebral dysfunction occur when brain cells swell.
Fluid imbalance – Clinical Dehydration
ECV fluid and Hypernatremia occur at the same time
Fluid Imbalance – Clinical Dehydration, signs
common with gastroenteritis, severe vomitting, and diarrhea
Electrolyte Balance
electrolyte homeostasis: Electrolyte intake/absorption, electrolyte distribution, electrolyte output are balanced.
Electrolyte Imbalance – 2 types
. Plasma Electrolyte excess – when electrolyte intake greater than electrolyte output or shift of electrolyte from cells or bone into the ECF.
.Plasma Electrolyte deficit – when electrolyte intake less than electrolyte output or shift of electrolyte from ECF into cells or bone
Electrolyte Imbalances – Potassium Imbalances, Hypokalemia
abnormal low potassium concentration in the blood.
Electrolyte imbalance – potassium imbalances, hypokalemia, common causes
diarrhea, repeated vomitting, use of potassium wasting diuretics.

Dangerous due to hypokalemia can cause muscle weakness (Respiratory muscles) and potentially life-threatening cardiac dysrhythmias.

Electrolyte imbalance – potassium imbalances, hypokalemia, common treatment
increase potassium intake or reduce their risk of hypokalemia
Electrolyte imbalance – potassium imbalances, hyperkalemia
abnormally high potassium ion concentrate in the blood
Electrolyte imbalance – potassium imbalances, hyperkalemia, common causes
oliguria (decreased urine output), this can causes muscle weakness, potentially life-threatening cardiac dysrhythmias and cardiac arrest
Why the concept of potassium imbalance is important?
if pt has abnormal low urine output, this imply the pt can have hyperkalemia.
Electrolyte Imbalance – Calcium imbalance, hypocalcemia
abnormally low calcium concentration in the blood.
Age
Very Young: ECV defecit, osmolality imbalances, clinical dehydration. Very Old: ECV excess or deficit, Osmolality imbalances
Environment
Sodium rich diet: ECV excess
Electroyle poor diet: Electrolyte deficits
Hot Weather: Clinical Dehydration
Gastrointestinal Output
DIARRHEA: ECF deficit, Clinical dehydration, Hypokalemia, Hypocalcemia (If chronic), Hypomanesemia (If chronic), metabolic acidosis. DRAINAGE: (e.g. NG Suctioning, Fistulas), ECV deficit, Hypokalemia, Metabolic acidosis if intestinal or pancreatic drainage. VOMITING: ECV Deficit, Clinical Dehydration, Hypokalemia, Hypomagnesemia, Metabolic Alkalosis
Chronic Diseases
CANCER: Hypercalcemia with Tumor Lysis Syndrome (Hyperkalemia, Hypocalcemia, Hyperphosphatemia, other imbalances, depending on side effects of therapy) CHRONIC OBSTRUCTIVE PULMONARY DISEASE: Respiratory acidosis. CIRRHOSIS: ECV excess, Hypokalemia. HEART FAILURE: ECV excess, other imbalances, depend on therapy. OLIGURIC RENAL DISEASE: ECV excess, Hyperkalemi, Hypermagnesemia, Hyperphoshatemia, Metabolic Acidosis.
Trauma
Burns: ECV deficit, Metabolic Acidosis
Crush Injuries: Hyperkalemia
Head Injuries: Hyponatremia or Hypernatremia, depnding on ADH response
Hemorrhage: ECV defecit, Hyperkalemia if circulatory shock
Therapies
Diuretics and other medications
IV Therapy: ECV excess, Osmolality Imbalances, Electrolyte excesses
PN: Any fluid or electrolyte imbalnace, depending on components of solution
PPT
Fluid Balance depends on
Fluid intake
Thirst regulates fluid intake
~2300 mL/day

Fluid distribution
Extracellular and intracellular
Vascular and interstitial

Hormonal Influences
Antidiuretic hormone
Renin-angiotensin-aldosterone mechanism
Atrial natriuretic peptides

Fluid output
Through kidneys, skin, lungs, and GI tract
Insensible loss
Sensible loss

PPT

Edema

Both ↑ Intravascular & ↑ Interstitial volume
Most apparent around the eyes & dependent tissues
Pitting edema
Anasarca = generalized edema
Mechanisms:
↑ Capillary hydrostatic pressure – fluid volume excess
↓Plasma oncotic pressure – malnutrition, kidney and liver disease
↑ Capillary permeability permits leaking of fluids & proteins – tissue trauma, allergic reactions
Lymphatic obstruction/ surgical removal of lymph nodes impairs lymph drainage – backs into vascular compartment
Electrolyte Balance
You can best understand electrolyte balance by considering the three processes involved in electrolyte homeostasis: electrolyte intake and absorption, electrolyte distribution, and electrolyte output.
•Interplay of electrolyte intake and absorption, electrolyte distribution, and electrolyte output determines the balance of K+, Ca2+, Mg2+, and phosphate.
Intake comes from foods and beverages. Some substances enhance or hinder electrolyte absorption.
Although sodium is an electrolyte, it is not included here because serum sodium imbalances are the osmolality imbalances discussed previously.
Electrolyte distribution is an important issue. Note that the electrolyte values that you review from laboratory reports are measured in blood serum and do not measure intracellular levels.
Electrolyte output occurs through normal excretion in urine, feces, and sweat. Output also occurs through vomiting, drainage tubes, and fistulas. When electrolyte output increases, electrolyte intake must increase to maintain electrolyte balance. Similarly, if electrolyte output decreases, as with oliguria, electrolyte intake must also decrease to maintain balance.
PPT Case study
Mrs. Reynolds’ physician has admitted her for observation and has obtained a blood sample for electrolyte levels, CBC, and an ECG. Orders include nothing by mouth, an IV infusion of 0.9% saline at 125 mL/hr, intake and output (I&O) recordings, and vital signs every 4 hours, in addition to daily weights.
What assessment activities do you anticipate Robert will perform?
[Discuss:
Ask Mrs. Reynolds to describe her nausea and what accompanying signs and symptoms she is experiencing.
Conduct an examination of GI and urinary function.
Assess her vital signs.
Assess Mrs. Reynolds’ skin and mucous membranes for indicators of dehydration.
Evaluation her laboratory vales and ECG results.]
Electrolyte imbalance

-emia
-Hyponatremia
-Hypernatremia
-Hypokalemia
-Hyperkalemia
-Hypocalcemia
-Hypercalcemia
-Hypomagnesemia
-Hypermagnesemia

Q1: What factors can discrupt electrolyte homeostasis?
Q2: What happen when electrolyte is excessive in ECF?
Q3: what happen when electrolyte is low in ECF?

Q4: What is hypokalemia?
Q5: What are common causes of hypokalemia?
Q6:How to correct Hypokalemia?
Q7: What are symptoms and signs of hypokalemia?

Similar to the rest of the electrolyte, ask similar questions.

– emia = blood
Hyper- excessive
Hypo – deficient
Kal – potassium
Calc – calcium
magnes – magnesium

Electrolyte imbalance could be caused by:
Factors such as diarrhea, endocrine disorders, and medications that disrupt electrolyte homeostasis cause electrolyte imbalances.

Electrolyte intake greater than electrolyte output or a shift of electrolytes from cells or bone into the ECF causes plasma electrolyte excess. Electrolyte intake less than electrolyte output or shift of electrolyte from the ECF into cells or bone causes plasma electrolyte deficit.

Hypokalemia:
Hypokalemia is abnormally low potassium concentration in the blood. Hypokalemia results from decreased potassium intake and absorption, a shift of potassium from the ECF into cells, and an increased potassium output.

Common Causes of hypokalemia are:
Common causes of hypokalemia from increased potassium output include diarrhea, repeated vomiting, and use of potassium-wasting diuretics.

What are symptoms and signs of hypokalemia?
Hypokalemia causes muscle weakness, which becomes life threatening if it includes respiratory muscles and potentially life-threatening cardiac dysrhythmias.

How to correct Hypokalemia?
People who have these conditions need to increase their potassium intake to reduce their risk of hypokalemia.

Hyperkalemia:
Hyperkalemia is abnormally high potassium ion concentration in the blood. Its general causes are increased potassium intake and absorption, shift of potassium from cells into the ECF, and decreased potassium output.
People who have oliguria (decreased urine output) are at high risk of hyperkalemia from the resultant decreased potassium output unless their potassium intake also decreases substantially. Understanding this principle helps you remember to check urine output before you administer IV solutions containing potassium. Hyperkalemia can cause muscle weakness, potentially life-threatening cardiac dysrhythmias, and cardiac arrest.

Hypocalcemia:
Hypocalcemia is abnormally low calcium concentration in the blood. The physiologically active form of calcium in the blood is ionized calcium. Total blood calcium also contains inactive forms that are bound to plasma proteins and small anions such as citrate. Factors that cause too much ionized calcium to shift to bound forms cause symptomatic ionized hypocalcemia. People who have acute pancreatitis frequently develop hypocalcemia because calcium binds to undigested fat in their feces and is excreted. This process decreases absorption of dietary calcium and increases calcium output by preventing resorption of calcium contained in GI fluids. Hypocalcemia increases neuromuscular excitability, which is the basis for its signs and symptoms.

Hypercalcemia:
Hypercalcemia is abnormally high calcium concentration in the blood. Hypercalcemia results from increased calcium intake and absorption, shift of calcium from bones into the ECF, and decreased calcium output. Patients with cancer often develop hypercalcemia because some cancer cells secrete chemicals into the blood that are related to parathyroid hormone. When these chemicals reach the bones, they cause shift of calcium from bones into the ECF. This weakens bones, and the person sometimes develops pathological fractures (i.e., bone breakage caused by forces that would not break a healthy bone). Hypercalcemia decreases neuromuscular excitability, the basis for its other signs and symptoms, the most common of which is lethargy.

Hypomagnesemia:
Hypomagnesemia is abnormally low magnesium concentration in the blood. Its general causes include decreased magnesium intake and absorption, shift of plasma magnesium to its inactive bound form, and increased magnesium output. Signs and symptoms are similar to those of hypocalcemia because hypomagnesemia also increases neuromuscular excitability.

Hypermagnesemia:
Hypermagnesemia is abnormally high magnesium concentration in the blood. End-stage renal disease causes hypermagnesemia unless the person decreases magnesium intake to match the decreased output. Signs and symptoms are caused by decreased neuromuscular excitability, with lethargy and decreased deep tendon reflexes being most common.

Mrs. Reynolds’ physician has admitted her for observation and has obtained a blood sample for electrolyte levels, CBC, and an ECG. Orders include nothing by mouth, an IV infusion of 0.9% saline at 125 mL/hr, intake and output (I&O) recordings, and vital signs every 4 hours, in addition to daily weights.
What assessment activities do you anticipate Robert will perform?
[Discuss:
Ask Mrs. Reynolds to describe her nausea and what accompanying signs and symptoms she is experiencing.
Conduct an examination of GI and urinary function.
Assess her vital signs.
Assess Mrs. Reynolds’ skin and mucous membranes for indicators of dehydration.
Evaluation her laboratory vales and ECG results.]
Acid & Base balalnce

Homeostasis of acid acid-base balance is ___, ____, ____?

For optimal cell function, the body maintains a balance between acids and bases. Acid-base homeostasis is the dynamic interplay of three processes: acid production, acid buffering, and acid excretion. Normal acid-base balance is maintained with acid excretion equal to acid production. The more H+ ions that are present, the more acidic is the solution.
The degree of acidity in blood and other body fluids is reported from the clinical laboratory as pH. If pH goes outside the normal range, enzymes within cells do not function properly; hemoglobin does not manage oxygen properly; and serious physiological problems, including death, may occur. Laboratory tests of a sample of arterial blood called arterial blood gases (ABGs) are used to monitor a patient’s acid-base balance.
[Review Table 41-6 on text p. 892 Arterial Blood Gas Measures.]
Acid & base balance

what are two types of acids?

What is the function of the buffering?

What is the major ECF buffer? what are other buffers are in the system?

Production: Cellular metabolism constantly creates two types of acids: carbonic acid and metabolic acids. Cells produce carbon dioxide (CO2), which acts as an acid in the body by converting to carbonic acid.
Metabolic acids are any acids that are not carbonic acid. They include citric acid, lactic acid, and many others.
Buffering: If too many free H+ ions are present, a buffer takes them up, so they no longer are free. If too few are present, a buffer can release H+ ions to prevent an acid-base imbalance. Buffers work rapidly—within seconds.
All body fluids contain buffers. The major buffer in ECF is the bicarbonate (HCO3−) buffer system, which buffers metabolic acids. It consists of a lot of bicarbonate and a small amount of carbonic acid (normally a 20:1 ratio). Addition of H+ released by a metabolic acid to a bicarbonate ion makes more carbonic acid. Now the H+ is no longer free and will not decrease the blood pH (see slide for green equation).
If too few H+ ions are present, the carbonic acid portion of the buffer pair will release some, increasing the bicarbonate, again returning pH to normal (see slide for bottom two blue equations).
Other buffers include hemoglobin, protein buffers, and phosphate buffers. Cellular and bone buffers also contribute. Buffers normally keep the blood from becoming too acid when acids that are produced by cells circulate to the lungs and kidneys for excretion.
Buffer

What happen when too much H+ ion in the body fluids?
What happen when too little H+ ion in the body fluids?

What causes acidosis?
What causes alkolossis?

Immediate compensation but limited in its capacity to maintain pH balance
Neutralizes excess acids or bases
If too much H+ ion in the body fluids then buffers (HCO¯3) bind with the H+ ion.
If too little H+ ion in the body fluids then buffers (H2CO3) release H+ ion.
Immediate compensation but limited in its capacity to maintain pH balance

Neutralizes excess acids or bases
If too much H+ ion in the body fluids then buffers (HCO¯3) bind with the H+ ion.
If too little H+ ion in the body fluids then buffers (H2CO3) release H+ ion.

E.g. If strong acid is instilled in the ECF then Bicarbonate (HCO¯3) is combined to neutralize the acid and pH is only slightly decreased. If the acid overwhelms the available Bicarbonate then ACIDOSIS occur.

E.g. If strong base is added to ECF then Carbonic acid (H2CO3) will combine to neutralize the base and pH is only slightly elevated. If the base overwhelms the Carbonic acid available then ALKALOSIS occur.

Acid & Base Balance

What are the two acid secretion systems?

Example of alterations in respiratory rate and dept maintain the carbonic acid portion of acid-base balance?

What happen to a patient who have lung disease? what happen to their acid and base balance?

What is the kidney’s function in the acid base balance?

What is the function of HCO3- ? What is the function of phosophate buffer?

The body has two acid excretion systems: lungs and kidneys. The lungs excrete carbonic acid; the kidneys excrete metabolic acids.
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. 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.

The kidneys excrete all acids except carbonic acid. They secrete H+ into the renal tubular fluid, putting HCO3− back into the blood at the same time. If too many H+ ions are present in the blood, renal cells move more H+ ions into the renal tubules for excretion, retaining more HCO3− in the process. If too few H+ ions are present 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 H+ ions in the tubules to make NH4+, ammonium ions. Buffering by phosphate and the creation of NH4+ turn free H+ ions into other molecules in the renal tubular fluid. 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.

Acid-base imbalance

How can see a patient and know the patient who has cabonic or metabolic acids? what do we look at to make the determination?

Recall that the kidney or lung cannot compensate for itself.
Therefore the kidneys compensate for respiratory acid-base imbalances; the respiratory system compensates for metabolic acid-base imbalances.
Acid-base imbalances are caused by excesses or deficits of carbonic or metabolic acids, manifested as changes in level of consciousness and abnormalities of PaCO2, HCO3−, and pH.
Physical Assessent

If a patient gain 1kg, how much fluid he/she should retain in the body?

Why do we weight patient? It is useful for which type of patient?

Data gathered through a focused physical assessment validate and extend the information collected in the patient history.

Daily weights are an important indicator of fluid status. Each kilogram (2.2 lbs) of weight gained or lost overnight is equal to 1 L of fluid retained or lost. These fluid gains or losses indicate changes in the amount of total body fluid, usually ECF, but do not indicate a shift between body compartments.

Weigh daily patients with heart failure and those who are at high risk for or who actually have ECV excess.

Daily weights are also useful for patients with clinical dehydration or other causes of or risks for ECV deficit.

Weigh the patient at the same time each day with the same scale after a patient voids. Calibrate the scale each day or routinely.
The patient needs to wear the same clothes or clothes that weigh the same; if using a bed scale, use the same number of sheets on the scale with each weighing. Compare the weight of each day with that of the previous day to determine fluid gains or losses.

Look at the weights over several days to recognize trends. Interpretation of daily weights guides medical therapy and nursing care. Teach patients with heart failure to take and record their daily weights at home and to contact their health care provider if their weight increases suddenly by a set amount (obtain parameters from their health care providers). Recognizing trends in daily weights taken at home is important. Research shows that patients who are hospitalized for decompensated heart failure often experience steady increases in daily weights during the week before hospitalization. A weight gain of more than 2.2 lbs (1 kg) was associated with increased risk of hospitalization due to heart failure.

Measuring and recording all liquid intake and output (I&O) during a 24-hour period is an important aspect of fluid balance assessment. Compare a patient’s 24-hour intake with his or her 24-hour output. The two measures should be approximately equal if the person has normal fluid balance. To interpret situations in which I&Os are substantially different, consider the individual patient.

For example, if intake is substantially greater than output, two possibilities exist: The patient may be gaining excessive fluid or may be returning to normal fluid status by replacing fluid lost previously from the body.

Similarly, if intake is substantially smaller than output, two possibilities are known: The patient may be losing needed fluid from the body and developing ECV deficit and/or hypernatremia or may be returning to normal fluid status by excreting excessive fluid gained previously.

In most health care settings, I&O measurement is a nursing assessment. Some agencies require a health care provider’s order for I&O. If you want to measure I&O for a patient with compromised fluid status, check your agency policies to determine whether you can institute it or if you need a health care provider’s order.

Fluid intake includes all liquids that a person eats (e.g., gelatin, ice cream, soup), drinks, (e.g., water, coffee, juice), or receives through nasogastric or jejunostomy feeding tubes. IV fluids (continuous infusions and intermittent IV piggybacks) and blood components are also sources of intake. Water swallowed while taking pills and liquid medications counts as intake. A patient receiving tube feedings often receives numerous liquid medications, and water is used to flush the tube before and/or after medications. Over a 24-hour period, these liquids amount to significant intake and always are recorded on the I&O record.

Ask patients who are alert and oriented to assist with measuring their oral intake, and explain to families why they should not drink or eat from the patient’s meal trays or water pitcher.

Fluid output includes urine, diarrhea, vomitus, gastric suction, and drainage from postsurgical wounds or other tubes. Record a patient’s urinary output after each voiding. Instruct patients who are alert, oriented, and ambulatory to save their urine in a calibrated insert, which attaches to the rim of the toilet bowl. Teach patients and families the purpose of I&O measurements. Teach them to notify the nurse or nursing assistive personnel (NAP) to empty any container with voided fluid, or show them how to measure and empty the container themselves and report the results appropriately. Accurate I&O facilitates ongoing evaluation of a patient’s hydration status.

Review the patient’s laboratory test results and compare them with normal ranges to obtain further objective data about fluid, electrolyte, and acid-base balances. Serum electrolyte tests usually are performed routinely on any patient entering a hospital to screen for imbalances and serve as a baseline for future comparisons.
[Table 41-10 on text p. 899 covers Focused Nursing Assessments for Patients with Fluid, Electrolyte, and Acid-Base Imbalances.]

Mrs. Reynolds states that she has no appetite, is nauseous, and has been vomiting and has had diarrhea for 7 days.

Bowel sounds are hyperactive in all four quadrants. The patient has had only two loose stools since midnight. She voids with difficulty, with dark yellow urine. Her 24-hour intake was 1850 mL; her output was 2200 mL (of which urine was only 1000 mL).
Temperature 99.6° F; pulse 100 bpm; BP 110/60 mm Hg with no changes when standing

Respirations are 18 breaths per minute and nonlabored with bilateral breath sounds clear to auscultation.
Robert observes that Mrs. Reynolds’ skin is dry, and turgor is decreased. Inspection of mucous membranes reveals that they are dry with thick, clear mucus.
The patient’s admission weight of 143 lb was down 1 lb since admission.

[What conclusions can Robert draw from this information? Discuss.]
Implementation

– education
– who is at risk of dehydration? what is the nursing intervention?
– how to prevent and treat ECV deficit, hypernatremia, and electrolyte deficit?

Health promotion activities focus primarily on patient education. Teach patients and caregivers to recognize risk factors for developing imbalances and to implement appropriate preventive measures. Parents must understand that infants and children need to replace fluids when vomiting or diarrhea occurs. Adults, especially the elderly and the infirm, also need to replace fluids when increased perspiration occurs.
Patients with chronic health alterations often are at risk for developing fluid, electrolyte, and acid-base imbalances. They need to understand their own risk factors and the measures to be taken to avoid imbalances. Teach patients with chronic diseases and their family caregivers the early signs and symptoms of the fluid, electrolyte, and acid-base imbalances for which they are at risk, and what to do if these occur.
Acute care nurses administer medications and oral and IV fluids to replace fluid and electrolyte deficits or to maintain normal homeostasis; they also assist with restricting intake as part of therapy for excesses.

* Prevention and treatment of ECV deficit, hypernatremia, and electrolyte deficits are accomplished with enteral or parenteral administration of appropriate fluid.
Enteral replacements with oral fluids and electrolytes are indicated for patients who are able to drink. Oral replacements may be contraindicated when the patient is vomiting, has a GI tract obstruction, is at risk for obstruction, or has impaired swallowing.
A feeding tube is appropriate when the patient’s GI tract is healthy, but the patient cannot ingest fluids (e.g., after oral surgery, with impaired swallowing). Options for administering fluids include gastrostomy or jejunostomy instillations or infusions through small-bore nasogastric feeding tubes.

* Patients who have hyponatremia usually require restricted water intake. Patients who have very severe ECV excess sometimes have both sodium and fluid restrictions. 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.

* Parenteral replacement includes total parenteral nutrition (TPN), crystalloids, and colloids (blood and blood components).
Total Parenteral Nutrition (TPN) consists of IV administration of a complex, highly concentrated solution containing nutrients and electrolytes that is formulated to meet a patient’s needs.
Depending on their osmolality, PN solutions may be administered through a central IV catheter (high osmolality) or peripherally (lower osmolality).

Central Venous line
Central venous lines deliver intravenous fluid into the superior vena cava near the heart. (CVAD, Central venous access device.)
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).
[Shown is Figure 41-13 from text p. 905.]
IV therapy
The goal of IV fluid administration is to correct or prevent fluid and electrolyte disturbances. IVs allow direct access to the vascular system, permitting continuous infusion of fluids over a period of time.
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.
[Table 41-11 on text p. 905 presents types of IV solutions.]

An IV solution may be isotonic, hypotonic, or hypertonic.
Isotonic solutions have the same effective osmolality as body fluids. Sodium-containing isotonic solutions such as normal saline are indicated for ECV replacement to prevent or treat ECV deficit.
Hypotonic solutions have an effective osmolality less than body fluids, thus decreasing osmolality by diluting body fluids and moving water into cells.
Hypertonic solutions have an effective osmolality greater than body fluids. If they are hypertonic sodium-containing solutions, they increase osmolality rapidly and pull water out of cells, causing them to shrivel. The decision to use a hypotonic or hypertonic solution is based on the patient’s specific fluid and electrolyte imbalance.

Additives such as potassium chloride (KCl) are common in IV solutions. A health care provider’s order is necessary if an IV is to have additives added.
Administer KCl carefully because hyperkalemia can cause fatal cardiac dysrhythmias. Under no circumstances should it be administered by IV push (directly through a port in IV tubing).

Verify that a patient has adequate kidney function and urine output before administering an IV solution containing potassium. Patients with normal renal function who are receiving nothing by mouth should have potassium added to IV solutions. The body cannot conserve potassium, and the kidneys continue to excrete potassium even when the plasma level falls. Without potassium intake, hypokalemia develops quickly.

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, parenteral nutrition (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 (CRBSIs).

The National Quality Forum (NQF) 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 IV
•Initiation and maintenance of IV therapy require clinical decision making, skill, and organized procedures to maintain the sterility and patency of the system.
Correct selection and preparation of IV equipment assist in safe and quick placement of an IV line.
Because fluids infuse directly into the bloodstream, sterile technique is necessary.
The main IV fluid used in a continuous infusion flows through tubing called the primary line. The primary line connects to the IV catheter. Injectable medications such as antibiotics usually are added to a small IV solution bag and “piggybacked” as a secondary set into the primary line, or as a primary intermittent infusion to be administered over a 30- to 60-minute period.
The type and amount of solution are prescribed by the patient’s health care provider and depend on the medication added and the patient’s physiological status.
After you collect the equipment at the patient’s bedside, prepare to insert the IV line by assessing the patient for a venipuncture site.

Venipuncture is a technique in which a vein is punctured through the skin by a sharp rigid stylet. 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.

Nurses require specialized knowledge and education to place peripherally inserted central catheters (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.

After initiating a peripheral IV infusion and checking it for patency, regulate the rate of infusion according to the health care provider’s orders.

Regardless of the method used, nurses are responsible for monitoring fluid flow to prevent overinfusion or underinfusion.

Electronic infusion devices (EIDs), also called IV pumps or infusion pumps, deliver an accurate hourly IV infusion rate.

Nonelectronic volume control devices are used occasionally with an IV solution infused by gravity to prevent accidental infusion of a large fluid volume.

Over the needle cather
Shown is an over-the-needle catheter (or peripheral vascular access device) for venipuncture.
VADs that are short, peripheral IV catheters are available in a variety of gauges, such as the commonly used 20 and 22 gauges. A larger gauge indicates a smaller-diameter catheter.
A peripheral VAD is called an over-the-needle catheter; it consists of a small plastic tube or catheter threaded over a sharp stylet (needle). Once you have inserted the stylet and advanced the catheter into the vein, you withdraw the stylet, leaving the catheter in place.
These devices have a safety mechanism that covers the sharp stylet when withdrawing it to reduce the risk of needlestick injury.
Needleless systems allow you to make connections without using needles; this reduces needlestick injuries.
[Shown is Figure 41-14 from text p. 906.]
Common IV Site
-Elderly
-infant

-signs and symptom of infection site?

Common IV sites include (A) inner arm and (B) dorsal surface of the hand.
Venipuncture is commonly performed in the hand and arm.

Remember that the young, elderly, and frail have fragile veins. You will not insert an IV into an area that has signs of infection, infiltration, or thrombosis. 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.

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. Exudation 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.

Choose the most distal appropriate site. Using a distal site first allows for the use of proximal sites later if the patient needs a venipuncture site change.

[Review Box 41-6 on text p. 907 Focus on Older Adults: Protection of Skin and Veins During Intravenous Therapy.]
[Shown is Figure 41-15 from text p. 906.]

Initiating IV Therapy
After placing an IV line and regulating the flow rate, maintain the IV system. 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. 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 an opportunity for contamination. Never let IV tubing touch the floor.
IV tubing contains needleless injection ports through which syringes or other adaptors can be inserted for medication administration.
Patients receiving IV therapy over several days require periodic changes of IV fluid containers. 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.
To prevent the accidental disruption of an IV system, a patient often needs assistance with hygiene, comfort measures, meals, and ambulation.
Nurses monitor vigilantly for complications of IV therapy, which include fluid overload, infiltration, phlebitis, local infection, and bleeding at the infusion site.
The signs and symptoms of complications often arise rapidly; this 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. Phlebitis (i.e., inflammation of a vein) results from chemical, mechanical, or bacterial causes. Flood volume excess occurs when the fluid is administered too rapidly.
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.
[See also Box 41-7 on text p. 908 Evidence-Based Practice: Preventing Complications at Peripheral Intravenous Sites; Table 41-12 on text p. 910 Complications of Intravenous Therapy with Nursing Interventions; Table 41-13 on text p. 911 Infiltration Scale; and Table 41-14 on text p. 911 Phlebitis Scale.]
Blood Transfusion
– objective
Administration of blood or blood products requires a specific procedure for correctly identifying patient and blood products and responding quickly to transfusion reactions.
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).
Blood transfusions must be matched to each patient to avoid incompatibility. If incompatible blood is transfused (i.e., a patient’s RBC antigens differ from those transfused), the patient’s antibodies trigger RBC destruction in a potentially dangerous transfusion reaction (i.e., an immune response to the transfused blood components).
The most important grouping for transfusion purposes is the ABO system, which identifies A, B, O, and AB blood types. Determination of blood type is based on the presence or absence of A and B red blood cell (RBC) antigens. People with type O blood are considered universal blood donors because they can donate packed RBCs and platelets to people with any ABO blood type. People with type AB blood are called universal blood recipients because they can receive packed RBCs and platelets of any ABO type.
Another consideration when matching blood components for transfusions is the Rh factor, which refers to another antigen in RBC membranes. Most people have this antigen and are Rh positive; a person without it is Rh negative. People who are Rh negative receive only Rh-negative blood components.
Autologous transfusion (autotransfusion) is the collection and reinfusion of a patient’s own blood. Blood for an autologous transfusion most commonly is obtained by preoperative donation up to 6 weeks before a scheduled surgery. Autologous transfusions are safer for patients because they decrease the risk of mismatched blood and exposure to bloodborne infectious agents.
Transfusion of blood or blood components is a nursing procedure that requires an order from a health care provider. A blood transfusion reaction is one of the National Quality Forum’s patient safety measures that should be included in a health care institution’s public reporting of safety events. Patient safety is a nursing priority, and patient assessment, verification of health care provider’s order, and verification of correct blood products for the correct patient are imperative.
Perform a thorough patient assessment before initiating a transfusion, and monitor carefully during and after the transfusion.
For patient safety, always verify three things: that blood components delivered are the ones that were ordered; that blood delivered to the patient is compatible with the blood type listed in the medical record; and that the right patient receives the blood.
Together, two RNs or one RN and an LPN (check agency policy and procedures) must check the label on the blood product against the medical record and against the patient’s identification number, blood group, and complete name. If even a minor discrepancy exists, do not give the blood; notify the blood bank immediately to prevent infusion errors.
A transfusion reaction is an immune system reaction to the transfusion that ranges from a mild response to severe anaphylactic shock or acute intravascular hemolysis, both of which are life threatening.
Prompt intervention when a transfusion reaction occurs maintains or restores the patient’s physiological stability. When you suspect acute intravascular hemolysis, do the following:
Stop the transfusion immediately.
Keep the IV line open by replacing the IV tubing down to the catheter hub with new tubing and running 0.9% sodium chloride (normal saline).
Do not turn off the blood and simply turn on the 0.9% sodium chloride (normal saline) that is connected to the Y-tubing infusion set. This would cause blood remaining in the IV tubing to infuse into the patient. Even a small amount of mismatched blood can cause a major reaction.
Immediately notify the health care provider or emergency response team.
Remain with the patient, observing signs and symptoms and monitoring vital signs as often as every 5 minutes.
Prepare to administer emergency drugs such as antihistamines, vasopressors, fluids, and corticosteroids per health care provider order or protocol.
Prepare to perform cardiopulmonary resuscitation.
Save the blood container, tubing, attached labels, and transfusion record for return to the blood bank.
Obtain blood and urine specimens per health care provider order or protocol.
Circulatory overload is a risk when a patient receives massive whole blood or packed RBC transfusions for massive hemorrhagic shock, or when a patient with normal blood volume receives blood.
Transfusion of blood components that are contaminated with bacteria, especially gram-negative bacteria, can cause sepsis.
[See also Table 41-15 on text p. 911 ABO Compatibilities for Transfusion Therapy; Table 41-16 on text p. 913 Acute Adverse Effects of Transfusions.]

Nursing implementation
Blood Transfusions
Blood Groups: (Based on the antigens that are on the surface of an individual’s RBC)
Type A = A antigen → B antibodies
Type B = B antigen → A antibodies
Type AB = AB antigen → No antibodies (Universal Recipient)
Type O = Neither A or B antigen → AB antibodies (Universal dOnor)
Rhesus (Rh) Factor
Rh-positive (Rh+) = blood that contains Rh factor
Rh-negative (Rh-) = Rh factor not present in blood
Rh antibodies develop after first exposure and risk for antigen-antibody reaction & hemolysis of RBCs
Nursing process – implementation
Blood products
Whole blood – not commonly used except ine xtreme hemorrhage
Packed red blood cells – to increase O2 carrying capacity of the blood
Autologous red blood cells – client donates own blood
Platelets – replaces plateletzs in clients with bleeding disorders
Fresh frozen plasma – expands blood volume and provides clotting factors – no RBCs – no typing
Albumin and plasma rptoein factor – blood expander
Clotting factors and cryoprecipitate – for clotting deficiencies
Nursing process – implemetnation
Hemolytic – incompatibility between client’s and donors blood – chills, fever, headache, backache, dyspnea
Febrile – sensitivity of client’s blood to WBC, platelets or plasma – fever, chills, headache
Allergic (mild & severe) – sensitivity to infused plasma proteins – dyspnea, chest pain, circulatory collapse
Circulatory overload – blood adminidtered too fast – cough, dyspnea, crackles
Sepsis – contaminated blood – high fever, chills, vomiting
nursing process – medicaiton
Administering blood
(***Skill 52-6 pp.1475-1478***)
Check with another RN
Client’s name & ID
Number on blood bag label
ABO group & Rh factor on blood bag label
Transfusion within 4 hours from when the blood left the blood bank
Y-set for blood transfusion – hang with normal saline
Use #18 or #19 gauge catheter needle
Prime the IV line with Normal saline
(0.9% NaCl)
No other IV solutions should be administered with blood!!!
implementation
After experiencing acute alterations in fluid, electrolyte, or acid-base balance, patients often require ongoing maintenance to prevent a recurrence of health alterations. Older adults require special considerations to prevent complications from developing.
Patient and family teaching is important for preventing fluid, electrolyte, and acid-base imbalances and for effective restorative care.
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 that complications can be avoided or recognized promptly.
[Box 41-8 on text p. 914 summarizes patient education guidelines for home IV therapy.]
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. Patients or family members who are responsible for meal preparation need to learn to understand the nutritional content of foods and to read the labels of commercially prepared foods.
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.
Evaluation
Evaluation of a patient’s clinical status is especially important if acute fluid, electrolyte, and/or acid-base imbalances exist. A patient’s condition can change very quickly, and it is important to recognize impending problems by integrating information about his or her presenting risk factors and clinical status, effects of the present treatment regimen, and potential causative agent.
Some possible questions to ask if expected outcomes have not been met are shown on the slide. [Discuss ways to phrase questions to get honest answers from patients.]
[See also Figure 41-19 Critical thinking model for fluid, electrolyte, and acid-base balances evaluation.]
An elderly nursing home resident has refused to eat or drink for several days and is admitted to the hospital. The nurse should assess for which of the following?
1. Increased blood pressure
2. Weak, rapid pulse
3. Moist mucous membranes
4. Jugular vein distention
2

1. This option is indicative of fluid volume excess.
2. Correct. A client that has not eaten or drank anything for several days would be experiencing fluid volume deficit.
3. This option is indicative of fluid volume excess.
4. This option is indicative of fluid volume excess.

A man brings his elderly wife to the emergency department. He states that she has been vomiting and has had diarrhea for the past 2 days. She appears lethargic and is complaining of leg cramps. What should the nurse do first?

1. Start an IV.
2. Review the results of serum electrolytes.
3. Offer the woman foods that are high in sodium and potassium content.
4. Administer an antiemetic.

1. While the nurse may perform this intervention, assessment is needed initially.
2. Correct. Further assessment is needed to determine appropriate action.
3. While the nurse may perform this intervention, assessment is needed initially.
4. While the nurse may perform this intervention, assessment is needed initially.
An elderly man is admitted to the medical unit with a diagnosis of dehydration. Which signs or symptom is most representative of a sodium imbalance?

1. Hyperreflexia
2. Mental confusion
3. Irregular pulse
4. Muscle weakness

1. Because calcium contributes to the function of voluntary muscle contraction, this option is more appropriate for calcium imbalances.
2. Correct. Sodium contributes to the function of neural tissue.
3. Because potassium and calcium contribute to cardiac function, irregular pulse is more likely to be associated with those alterations.
4. Because calcium contributes to the function of voluntary muscle contraction, this option is more appropriate for calcium imbalances.
Which client statement indicates a need for further teaching regarding treatment for hypokalemia?

1. “I will use avocado in my salads.”
2. I will be sure to check my heart rate before I take my digoxin.”
3. “I will take my potassium in the morning after eating breakfast.”
4. “I will stop using my salt substitute.”

1. Avocado is higher in potassium than most foods.
2. Hypokalemia can potentiate digoxin toxicity and checking the pulse will help the client to avoid this.
3. It is important to take potassium with food to avoid gastric upset.
4. Correct. Salt substitutes contain potassium. The client can still use it within reason.
A client is admitted to the hospital for hypocalcemia. Nursing interventions relating to which system would have the highest priority?

1. Renal
2. Cardiac
3. Gastrointestinal
4. Neuromuscular

1. Incorrect.
2. Incorrect.
3. Incorrect.
4. Correct. The major clinical signs and symptoms of hypocalcemia are due to increased neuromuscular activity.