NURS 3812: Exam 3

F&Es definitions

Process of regulating the extracellular fluid volume, body fluid osmolality, and plasma concentrations of electrolytes

volume vs. osmolality

volume = amount of fluid , osmolality = degree of concentration

Intracellular fluid

fluid inside the cells

extracellular fluid

fluid outside the cells that includes intravascular, interstitial, and transcellular fluids

intravascular fluid

liquid part of the blood (plasma)

intersitial fluid

fluid between the cells and outside blood vessels

transcellular fluid

fluid in areas such as cerebrospinal, pleural, etc

intracellular vs. extracellular space

• Most fluid is located in the intracellular space (inside cells)

• The rest of fluid is in the extracellular space (interstitial, vascular space, and transcellular)

  • Vascular - liquid part of blood

  • Interstitial - fluid between cells and outside blood vessels

  • Transcellular - eg. cerebral spinal fluid, synovial fluid

Intake and absorption

• oral, IV, NG

• increased osmolality = thirst response (this is decreased in older adults)

Output

• normal = urine, feces, skin/sweagt, lungs

• abnormal = emesis, hemorrhage, wound drainage

• regulated by kidneys - aldosterone (Na+ H20), ADH (H2O)

why do infants and children have a more vulnerable fluid balance?

• unable to communicate thirst

• larger ECF volume = faster fluid loss

• higher rates of metabolism = use up more H20

• higher percentage of body content water = need more H20 to maintain balance

• higher BSA (body surface area) to volume = lose more H20 through skin (sweating)

• immature kidneys = little reserve/need electrolytes

why do older adults have a more vulnerable fluid balance?

increased risk for ECV deficit and dehydration d/t:

• lower percent of body weight as water, decreased thirst response, and decreased kidney function

• chronic diseases and medications place them at risk for ECV imbalances

• those with incontenence may restrict fluids placing them at risk for hypernatremia and ECV defecit

types of fluid imbalances

• clinical dehydration

• fluid volume deficit

• fluid volume excess

clinical dehydration

• loss of water

• without loss of Na+ (high sodium)

• decreased volume with increased osmolality (concentration)

• extracellular volume deficit and hypernatremia (high sodium)

• water shifts from inside of cell to the extracellular space = cell shrinkage

fluid volume deficit

• loss of both water and electrolytes

• decreased volume

fluid volume excess

• too much isotonic fluid

• increased volume

cues/causes of clinical dehydration

• lack of water intake

• gastrointestinal losses ( vomiting, diarrhea, NGT suction)

• prolonged fever

• excessive sweating (marathons, working outside in hot weather, tachypnea in infants, radiant warmer/phototherapy for newborns)

• medications like benzodiazepines(decrease thirst sensation) and diuretics (excess urination)

• poor thirst response (older adults)

• unable to voice thirst (infants)

manifestations of clinical dehydration in adults

• Manifestations

  • General: Postural hypotension, ↑HR, thready pulse, sudden weight loss, dry mucous membranes, poor skin turgor*, flat neck veins, dark yellow urine, ↓LOC (confusion, lethargy, coma), thirst, seizures with rapid change, ↑temp

  • Severe: restlessness, confusion, ↑HR & ↓BP, oliguria (UO<30mL/hr), cold clammy skin, seizures

• Labs:

  • ↑ Na+ >145mEq/L, ↑ serum osmolality > 295mOsm/kg, ↑hematocrit, ↑BUN (>20mg/dL) showing hemoconcentration, ↑urine specific gravity (>1.030)

manifestations of clinical dehydration in infants and children

• Fewer wet diapers than usual

• No tears when crying

• Mucous membranes dry and sticky

• Less playful, more tired, cranky

• Lethargy

• Very poor skin turgor

• Increased respiraotry rate

• Sunken fontanel

• Sunken eyes with dark circles

• Abnormal skin color/temperature

Isotonic IV fluid

• No movement of water b/t ECF and ICF = expansion of ECF

• 0.9% NaCl, lactated ringer's

Hypotonic IV fluid

• ECF has fewer solutes than fluid in cells = water moves from extracellular space into cells

• 0.45% NaCl

Hypertonic IV fluid

• ECF has more solutes than within cells = water leaves cells and interstitial space into plasma 

• 3% NaCl (cerebral edema and symptomatic hypernatremia), D5% in 0.45% NaCl (treat hypovolemia), D5 in 0.9% NaCl

A nurse caring for client who is experiencing dehydration. Which of the following findings should the nurse identify associated with this condition? Select all that apply. 

1. Thready pulse

2. Dry mucous membranes

3. BUN 30 mg/dL

4. Urine output of 90 mL/hr

5. Blood pressure of 90/50

1. Thready pulse

2. Dry mucous membranes

3. BUN 30 mg/dL

4. Urine output of 90 mL/hr

5. Blood pressure of 90/50

Extracellular volume deficit/ Fluid volume deficit/ hypovolemia

• decreased volume with normal osmolality

• Extracellular space holds more Na+.

• Output of isotonic fluid exceeds intake of sodium containing fluids.

• Insufficient isotonic fluid in the extracellular. 

risk factors for fluid volume deficit

• blood loss

• GI losses (diarrhea and vomiting)

• severe burns

• excessive sweating without water and salt intake

• fever

• medications (diuretics)

• altered intake (impaired swallowing, prolonged NPO, confusion)

difference between clinical dehydration and fluid volume deficit

• Clinical Dehydration = decreased fluid and too concentrated

• fluid volume deficit/hypovolemia = decreased volume with normal osmolality

  

Cues of fluid volume deficit

• Manifestations

  • General: thirst, dryness of mucosa, decreased skin turgor*, flat neck veins, dark urine, and decreased urine output, sudden weight loss, increased HR, thready pulse

  • Severe: extreme thirst, restlessness, confusion, increasing HR & worsening hypotension, oliguria (<30mL/hr), cold clammy skin

• Labs

  • ↑hematocrit (>52% males, >47% females) - unless related  to bleeding then low, ↑BUN (>20mg/dL) showing hemoconcentration, ↑urine specific gravity (>1.030)

Fluid volume deficit interventions

• Goal: treat underlying cause and restore fluid and electrolyte balance 

• Interventions:

  • Depending on severity

  • Mild: oral rehydration with electrolytes (pedialyte, sports drinks) 

    • Peds: 1 cup (240 ml) for every 4.54 kg (10 lbs) - start with small sips 5 mL every 1-2 minutes

  • Moderate to severe: isotonic IV fluids: 0.9% normal saline or lactated ringers 

    • Moderate to severe changes in vitals, symptomatic, unable to keep fluids down

    • Peds: IV bolus 20 mL/kg of 0.9% NS over 10-20 minutes

  • Treat underlying cause example:

    • If related to trauma/blood loss: packed red blood cells

  • Monitor: weight, I&Os, s/s of FVD and fluid overload with IVFs

  • Fall prevention

Evidence of successful rehydration: Pediatric 

• Moist mucous membranes

• Sodium and potassium within normal limits

• Voiding >1 mL/kg/h

• Capillary refill of 2s or less

• Skin turgor brisk (Fontanelle flat)

• Fluid intake and output balanced

• Vital signs within normal limits

• Behavior normal (developmentally appropriate)

fluid volume excess/fluid volume overload

• increased volume with normal osmolality

• Too much isotonic fluid in the extracellular space

• Intake of sodium-containing isotonic fluid exceeds output

• Too much water and sodium

cues of fluid volume overload

• Manifestations can vary based on cause:

  • General: sudden weight gain (1L fluid = 1kg or 2.2 lbs), edema (not a good indicator compared to weight), full neck veins, crackles in lungs, dyspnea, bounding pulse

  • Severe: confusion, pulmonary edema

• Labs:

  • ↓hematocrit <40% M, <36% F & ↓BUN (<10mg/dL - except not in kidney failure baseline will be high) hemodilution 

risk factors for fluid volume overload

• heart failure

• kidney fialure

• excessive Na+ containing IV fluids

• cirrhosis

interventions for fluid volume overload

• Goal: restore fluid balance - remove excess fluid

• Interventions:

  • Impaired Gas Exchange -Fluid in lungs - elevate HOB, supplemental O2, possible IV diuretics (furosemide), dialysis (End stage kidney disease)

  • Fluid Imbalance -Daily weight: 1kg (2.2lb) in on day = 1L of fluid gained, monitor Intake and output, Edema in legs - elevate, medications, fluid and Na restrictions

  • Manage the cause:

    • Fluid and sodium restriction

    • Medication Regimen

    • Dialysis if missed sessions 

Fluid moves between blood vessels and interstitial fluid by filtration; water moves between ECF and ICF by osmosis; both processes maintain fluid and electrolyte balance.

true

Electrolytes play a critical role in:

• Balancing body fluids (Na+)

• Cerebral function (Na+)

• Regulating heart rhythm

• Supporting neuromuscular function 

(K+, Ca+, Mg+)

Electrolyte homeostasis involves 3 processes:

1. intake and absorption

2. distribution within the body

3. output and loss

electrolyte distribution in the body

• Na+ high concentration in the ECF

• K+ inside cels

• Mg2+ inside cells and bones

• Ca2+ in bones  (Calcitonin moves Ca2+ into bone & PTH shift Ca+ from bone to ECF)

clients at greatest risk for electrolyte imbalances

• Infants and children, older adults, clients with cognitive impairment, clients with chronic illnesses

• Acute illness or trauma

  • Burns, hemorrhage, head injuries

• Chronic illness

  • Renal disease, heart failure, cancer

• Medications

  • Diuretics, laxatives 

Electrolyte Imbalance Causes

• Output greater than intake and absorption

  • Examples: prolonged anorexia, lack foods rich in electrolytes, etc.

• Output less than intake and absorption 

  • IV infusions, oliguria 

• Distribution altered 

  • Shifting of electrolytes out of their normal location (K+, Mg+, Ca+ moving into ECF)

Homeostasis:

the ability of the body to maintain internal stability while adjusting to changing conditions

Acid-base balance

process of regulating the pH, bicarbonate concentration (HCO3), and partial pressure of carbon dioxide (CO2) of body fluids

pH definition

• degree of acidity or alkalinity

• Expected range for human blood is very narrow and regulated by homeostatic processes

pH ranges

• Low pH < 7.35 = acidotic (too much acid)

• High pH >7.45 = basic (alkaline) (too little acid)

• Cells and Tissues cannot function optimally or at all if the pH goes too far out of range

What are some contributors towards our bodies’ Acidic content? 

• Carbon Dioxide (CO2)   

• Stomach acid

• Lactic Acid 

• Ketoacidosis 

What is the main contributor for Alkaline content? 

• Bicarbonate (HCO3-) 

What body system primarily regulates bicarbonate (HCO3)?

kidneys

What body system regulates Carbon Dioxide (CO2)?

lungs

• Hyperventilation (Increasing respiratory rate) -CO2 is breathed off 

• CO2 is breathed off 

• ↑CO2 in blood = ↑ resp. rate and depth = to ↓ CO2 level

• Hypoventilating (decreasing respiratory rate)

-CO2 is retained 

• ↓CO2 = ↓ resp. rate and depth = to ↑ CO2 level

respiratory response in lungs

• When the body senses an acidic or alkaline pH, this can trigger a response in the lungs to alter respiration rate  

• Measured by PaCO2 

• FAST response (minutes/hours) 

METABOLIC (Renal) Response: Kidneys

• When the body senses an acidic or alkaline pH, this can trigger a response in the kidneys to alter bicarbonate excretion or absorption

• The kidneys filter acidic byproducts and HCO3– and either excrete them in the urine or reabsorb them back into the bloodstream

• Measured by HCO3- 

• SLOW response (24-48 hours to completely respond) 

difference between respiratory and metabolic response to pH shift

• respiratory = FAST response (minutes/hours) 

• metabolic = SLOW response (24-48 hours to completely respond) 

What are some potential causes of respiratory acidosis?

• Respiratory depression (sedatives, opioid use)

• Inadequate chest expansion (trauma or weakened muscles)

• Airway obstruction (sleep apnea) 

• Reduced alveolar-capilary diffusion (pneumonia, emphysema/COPD, acute respiratory distress, pulmonary edema, PE)

hint: what would cause the lungs to not be able to remove enough CO2 from the body

what are some potential causes of metabolic acidosis?

• Overproduction of hydrogen ions (lactic acidosis: shock, diabetic ketoacidosis, starvation)

• Underelimination of hydrogen ions (kidney failure)

• Underproduction of HCO3 (kidney failure, liver failure, pancreatitis)

• Overelimination of HCO3 (diarrhea)

what would cause the body to lose HCO3? What is the most commonly known cause of metabolic acidosis?

what are some potential causes of respiratory alkalosis?

• Any condition that results in hyperventilation (pain, anxiety, fever, sepsis, fever (esp. infants)), trauma

• When hyperventilation occurs, the body exhales too much CO2 and RESPIRATORY ALKALOSIS can occur —> loss of CO2

Hint: what would cause hyperventilation?

what are some potential causes of metabolic alkalosis?

• Decrease of acids:

  • Prolonged vomiting

  • Gastric suctioning

  • Excessive diuretic use

• Increase in base (HCO3):

  • Excessive antacid use

  • Renal impairment

hint:  what would cause the body to lose acid?

Causes of Hypocalcemia (↓Ca+)

Lack Ca+ foods, poor absorption (chronic diarrhea, lack vit D), hypoparathyroidism

Findings of Hypocalcemia (↓Ca+)

• Increased neuromuscular excitability - +chvostek and trousseau, twitching, hyper reflexes, seizures, laryngospasm, cardiac dysrhythmias

Causes and Findings of Hypercalcemia (↑Ca+)

• Causes:

• Vit D or Ca+ overdose, thiazide diuretics, hyperparathyroidism, bone cancer

• Findings:

• Decreased neuromuscular excitability - constipation, muscle weakness, dec reflexes, decreased LOC, cardiac dysrthythmias, bone pain

Causes and findings of Hypomagnesemia (↓ Mg+)

imbalances occur when normal homeostasis is disrupted and compensatory mechanisms fail (impaired function of organ systems) OR compensatory mechanisms are overwhelmed (external stressors are too severe or significant)

true

Arterial Blood Gases (ABGs)

• lab draw used to interpret acid-base balance in the body

  • acid-base status

  • underlying cause of imbalance

  • body’s ability to regulate pH

  • overall oxygen status

• sample drawn from an artery rather than a vein

• pH, PaCo2, HCO3, PaO2, O2 sats

Acidosis

= too much CO2 or not enough HCO3-

Alkalosis

= too much HCO3- or not enough CO2

ROME

Respiratory

Opposite

Metabolic

Equal

What are signs and symptoms of respiratory acidosis?

• Dyspnea

• Anxiety

• Confusion

• Fatigue, lethargy and sleepiness

• Flushed skin and sweating

• Tachycardia

Treatment for respiratory acidosis

• treat the underlying cause

• supplemental oxygen

• CDB, IS ?

• medications such as bronchodilators and corticosteroids

• mechanical ventilation if needed

Signs and symptoms of metabolic acidosis?

• long, deep breaths - Kussmaul respirations

• confusion, headache

• tachycardia

• loss of appetite

• nausea, vomiting

• hyperkalemia

treatment for metabolic acidosis

• treat the underlying cause

• remove additional acid

  • IV fluids and electrolytes

  • sodium bicarbonate (pH < 7.2)

  • LOW and SLOW

Signs and symptoms of respiratory alkalosis?

• hyperventilation!

• lightheadedness, dizziness

• confusion

• chest pain

• numbness in hands and feet

treatment for respiratory alkalosis

• decrease respiratory rate!

• talk them down

• pain, fever management

• rebreathing expired air

• fall precautions d/t neurologic and musculoskeletal impacts

• trat underlying cause

signs and symptoms of metabolic alkalosis?

• hypocalcemia (occurs with metabolic alkalosis)

  • muscle twitching or spasms

  • tremors

• tingling in face or lower extremities/feet

• nausea and vomiting

• lightheadness

• headache

treatment for metabolic alkalosis

• treat underlying cause

  • correct acid loss

  • correct electrolyte imbalance

  • correct fluid loss/imbalance

• fall precautions d/t neuromuscular effects

role of RN when caring for a client with an acid-base imbalance?

• assess for signs and symptoms of acid-base imbalance

• consider potential underlying causes and communicate with care team

• analyze lab values including ABGs

• monitor vital signs, RR and effort, neuromuscular status, I&O

• place the client on fall precautions if indicated

• administer medications and treatments as prescribed

treatment for sodium electrolyte imbalance

• monitor neuro!!

• hyponatremia: oral or IV replacement - SLOW to prevent rapid fluid shifts/seizures, fluid restrictions

• Hypernatremia: fluid replacement (D5W), Na+ restriction

treatment for low potassium imbalance (hypokalemia)

•  oral (meds or food) or IV replacement

  • IMPORTANT: IV must be diluted, do not exceed 40meq/L, rate 10 mEq/hr (NEVER push), continuous ECG monitoring, need adequate kidney function 

  • Oral meds - take with food - GI distress, never crush ER

    • Monitor UO - need adequate renal function

treatment for high potassium imbalance (hyperkalemia)

• restrict K+ rich foods

• renal failure = dialysis

• patiromer/sodium polystyrene sulfunate (K+ excreted through stool), IV insulin and dextrose (pushing K+ into cells) - monitor for hypogylcemia

  • Monitor cardiac 

treatment for magnesium electrolyte imbalance

• Hypomagnesemia: oral medication; IV for severe cases: monitor respiratory depression and renal function

  • Monitor neuromuscular and cardiac

• Hypermagnesemia: stop meds with Mg, IV calcium gluconate if severe (cardiac dysrhythmias)

  • Monitor neuromuscular, respiratory, & cardiac

treatment for calcium electrolyte imbalance

• Hypocalcemia: calcium and vit D supplements, dietary changes

  • Seizure precautions, monitor airway, cardiac and neuromusculare

• Hypercalcemia: oral phosphate, IV saline bolus + loop diuretic

  • Monitor neuromuscular, cardiac 

Lab value changes associated with dehydration

• concentrated hematocrit (Hct)

  • plasma becomes more concentrated with red blood cells

• increased serum sodium

  • dehydration resulting from lack of fluid intake vs. fluid loss

  • sodium is maintained, but fluid volume is deficient

  • hypernatremia can occur

hematocrit

= the proportion of red blood cells in the blood

Patient with febrile illness with diarrhea x 3 days will have these lab value changes:

• Lab value changes associated with GI loss:

  • Hypokalemia

  • Fluid volume deficit

• Lab value changes associated with febrile illness or infection:

  • Elevated WBC count

Patient with Heart failure exacerbation with fluid overload, admitted for diuresis will have these lab value changes:

• Lab value changes associated with fluid overload:

  • Dilution of Hematocrit

  • Decreased serum sodium concentration

• Lab value change associated with diuretics:

  • Loss of Potassium

  • Normalization of fluid balance and correction of dilutional hematocrit

Patient Postoperative day 1 status post Thyroidectomy will have these lab value changes:

• Lab value changes associated with endocrine disruptions caused by thyroid or parathyroid surgery:

  • Hypocalcemia

    • Calcium is regulated by the thyroid and parathyroid 

  • Possible blood loss during surgery

  • Possible dilutional Hct due to fluids received during surgery

what electrolyte does the thyroid and parathyroid regulate?

calcium

Calcium homeostasis is regulated primarily by two hormones:

• Calcitonin

• Parathyroid Hormone

when is each type of saline used?

3% NS - is hypertonic for clients experiencing hyponatremia

0.9%NS - is isotonic and used for hydration from vomiting diarrhea, hemorrhage, and shock

0.45% - is hypotonic and is used to treat hypernatremia and diabetic ketoacidosis. 

Dextrose 10% in water is hypertonic and used to treat hypoglycemia