week 2 Flashcards
Hydrostatic Pressure
Force within a fluid compartment
Major force that pushes water out of vascular system at capillary level
Oncotic Pressure
Osmotic pressure exerted by colloids in solution
Protein is a major colloid.
Fluid Shifts AND EDEMA
Plasma-to-interstitial fluid shift results in edema.
Elevation of hydrostatic pressure
Decrease in plasma oncotic pressure
Elevation of interstitial oncotic pressure
Effects of Edema (cont’d.)
-Functional impairment:
Restricts range of joint movement
Reduced vital capacity
Impaired diastole
-Pain:
Edema exerts pressure on nerves locally.
Headache with cerebral edema
Stretching of capsule in organs (kidney, liver)
-Dental practice:
Difficult to take accurate impressions
Dentures do not fit well
-Edema in skin:
Susceptible to tissue breakdown from pressure
Impaired arterial circulation
Ischemia leading to tissue breakdown
Fluid Movement Between ECF and ICF
-Water deficit (increased ECF)
Associated with symptoms that result from cell shrinkage as water is pulled into vascular system
-Water excess (decreased ECF)
Develops from gain or retention of excess water
Fluid Spacing
First spacing
Normal distribution of fluid in ICF and ECF
Second spacing
Abnormal accumulation of interstitial fluid (edema)
Third spacing
Fluid accumulation in part of body where it is not easily exchanged with ECF
Hypothalamic Regulation
- Osmoreceptors in hypothalamus sense fluid deficit or increase.
- -Stimulates thirst and antidiuretic hormone (ADH) release
- -Result in increased free water and decreased plasma osmolarity
Pituitary Regulation
Under control of hypothalamus, posterior pituitary releases ADH.
Stress, nausea, nicotine, and morphine also stimulate ADH release.
Adrenal Cortical Regulation
Releases hormones to regulate water and electrolytes
Glucocorticoids: Cortisol
Mineralocorticoids: Aldosterone
Renal Regulation
Primary organs for regulating fluid and electrolyte balance
-Adjusting urine volume: Selective reabsorption of water and electrolytes. Renal tubules are sites of action of ADH and aldosterone.
Cardiac Regulation
Natriuretic peptides are antagonists to the RAAS.
- -Produced by cardiomyocytes in response to increased atrial pressure
- -Suppress secretion of aldosterone, renin, and ADH to decrease blood volume and pressure
Gastrointestinal Regulation
Oral intake accounts for most water.
Small amounts of water are eliminated by gastrointestinal tract in feces.
Diarrhea and vomiting can lead to significant fluid and electrolyte loss.
Insensible Water Loss
Invisible vaporization from lungs and skin to regulate body temperature
- -Approximately 600 to 900 mL/day is lost.
- -No electrolytes are lost.
Age-Related Considerations
Structural changes in kidneys decrease ability to conserve water.
Hormonal changes lead to decrease in ADH and ANP.
Loss of subcutaneous tissue leads to increased loss of moisture.
Reduced thirst mechanism results in decreased fluid intake.
Nurse must assess for these changes and implement treatment accordingly.
Age-Related Considerations
Structural changes in kidneys decrease ability to conserve water.
Hormonal changes lead to decrease in ADH and ANP.
Loss of subcutaneous tissue leads to increased loss of moisture.
Reduced thirst mechanism results in decreased fluid intake.
Nurse must assess for these changes and implement treatment accordingly.
Fluid and Electrolyte Imbalances
Common in most patients with major illness or injury
- -Directly caused by illness or disease (burns or heart failure)
- -Result of therapeutic measures (IV fluid replacement or diuretics)
Extracellular Fluid Volume Imbalances
ECF volume deficit (hypovolemia)
- -Abnormal loss of normal body fluids (diarrhea, fistula drainage, hemorrhage), inadequate intake, or plasma-to-interstitial fluid shift
- -Treatment: Replace water and electrolytes with balanced IV solutions.
Fluid volume excess (hypervolemia)
- -Excessive intake of fluids, abnormal retention of fluids (HF), or interstitial-to-plasma fluid shift
- -Treatment: Remove fluid without changing electrolyte composition or osmolality of ECF.
Nursing Management Nursing Diagnoses
-Hypovolemia Deficient fluid volume Decreased cardiac output Risk for deficient fluid volume Potential complication: Hypovolemic shock
-Hypervolemia Excess fluid volume Risk for imbalanced fluid volume Ineffective airway clearance Risk for impaired skin integrity Disturbed body image Potential complications: Pulmonary edema, ascites
Fluid Deficit―Dehydration
-Insufficient body fluid
Inadequate intake
Excessive loss
Both
-Fluid loss often measured by change in body weight
-Dehydration more serious in infants and older adults
Water loss may be accompanied by loss of electrolytes and proteins (e.g., diarrhea).
Causes of Dehydration
- Vomiting and diarrhea
- Excessive sweating with loss of sodium and water
- Diabetic ketoacidosis (Loss of fluid, electrolytes, and glucose in the urine)
- Insufficient water intake in older adults or unconscious persons
- Use of concentrated formula in infants
Effects of Dehydration
- Dry mucous membranes in the mouth
- Decreased skin turgor or elasticity
- Lower blood pressure, weak pulse, and fatigue
- Decreased mental function, confusion, loss of consciousness
Manifestations of Dehydration
Decreased skin turgor and dry mucous membranes Sunken eyes Sunken fontanelles in infant Lower blood pressure, rapid weak pulse Increased hematocrit Increased temperature Decreasing level of consciousness Urine―low volume & high specific gravity
Nursing Management Nursing Implementation
I & O Monitor cardiovascular changes. Assess respiratory changes. Daily weights Skin assessment
Neurological function:
LOC,PERLA, Voluntary movement of extremities, Muscle strength, Reflexes
Calcium (Ca)
Excess: Hypercalcemia Thirst CNS deterioration Increased interstitial fluid
Deficit: Hypocalcemia Tetany Chvostek’s, Trousseau’s signs Muscle twitching CNS changes ECG changes
Magnesium (Mg)
EXCESS: Hypermagnesemia Loss of deep tendon reflexes (DTRs) Depression of CNS Depression of neuromuscular function
DEFICIT:
Hypomagnesemia
Hyperactive DTRs
CNS changes
Sodium (Na)
EXCESS: Hypernatremia Thirst CNS deterioration Increased interstitial fluid
DEFICIT:
Hyponatremia
CNS deterioration
Potassium (K)
EXCESS: Hyperkalemia Ventricular fibrillation ECG changes CNS changes
DEFICIT: Hypokalemia Bradycardia ECG changes CNS changes
Sodium
-Imbalances typically associated with parallel changes in osmolality
- Plays a major role in:
- -ECF volume and concentration
- -Generation and transmission of nerve impulses
- -Acid-base balance
Hypernatremia
Elevated serum sodium occurring with water loss or sodium gain
Causes hyperosmolality leading to cellular dehydration
Primary protection is thirst from hypothalamus.
Manifestations
Thirst, lethargy, agitation, seizures, and coma
Impaired LOC
Produced by clinical states
Central or nephrogenic diabetes insipidus
Hyponatremia
Results from loss of sodium-containing fluids or from water excess.
Manifestations
Confusion, nausea, vomiting, seizures, and coma
Potassium
Major ICF cation
Necessary for Transmission and conduction of nerve and muscle impulses Cellular growth Maintenance of cardiac rhythms Acid-base balance
Sources Fruits and vegetables (bananas and oranges) Salt substitutes Potassium medications (PO, IV) Stored blood
Hyperkalemia
High serum potassium caused by
Massive intake
Impaired renal excretion
Shift from ICF to ECF
Most common in renal failure
Manifestations: Cramping leg pain Weak or paralyzed skeletal muscles Ventricular fibrillation or cardiac standstill Abdominal cramping or diarrhea
Hypokalemia
Low serum potassium caused by:
- Abnormal losses of K+ via the kidneys or gastrointestinal tract
- Magnesium deficiency
- Metabolic alkalosis
Manifestations Most serious are cardiac. Skeletal muscle weakness (legs) Weakness of respiratory muscles Decreased gastrointestinal motility Impaired regulation of arteriolar blood flow
Calcium
Obtained from ingested foods
More than 99% combined with phosphorus and concentrated in skeletal system
Inverse relationship with phosphorus
Bones are readily available store
Functions:: Transmission of nerve impulses Myocardial contractions Blood clotting Formation of teeth and bone Muscle contractions
Hypercalcemia
High serum calcium levels caused by: Hyperparathyroidism (two-thirds of cases) Malignancy Vitamin D overdose Prolonged immobilization
Manifestations: Decreased memory Confusion Disorientation Fatigue Constipation
Hypocalcemia
Low serum Ca levels caused by:
Decreased production of PTH Acute pancreatitis Multiple blood transfusions Alkalosis Decreased intake
Manifestations:
Positive Trousseau’s or Chvostek’s sign
Laryngeal stridor
Dysphagia
Tingling around the mouth or in the extremities
Magnesium
50% to 60% contained in bone.
Coenzyme in metabolism of protein and carbohydrates
Factors that regulate calcium balance appear to influence magnesium balance.
Acts directly on myoneural junction
Important for normal cardiac function
Hypermagnesemia
High serum Mg caused by:
Increased intake or ingestion of products containing magnesium when renal insufficiency or failure is present
Manifestations: Lethargy or drowsiness Nausea/vomiting Impaired reflexes Somnolence Respiratory and cardiac arrest
Hypomagnesemia
Low serum Mg caused by:: Prolonged fasting or starvation Chronic alcoholism Fluid loss from gastrointestinal tract Prolonged parenteral nutrition without supplementation Diuretics
Manifestations:: Confusion Hyperactive deep tendon reflexes Tremors Seizures Cardiac dysrhythmias
Normal Saline (NS)
Isotonic No calories More NaCl than ECF 30% stays in IV (most) 70% moves out of IV
Expands IV volume --Preferred fluid for immediate response --Risk for fluid overload higher Does not change ICF volume Blood products Compatible with most medications --
Acid-Base Imbalance
Acidosis
Excess hydrogen ions
Decrease in serum pH
Alkalosis
Deficit of hydrogen ions
Increase in serum pH
Respiratory Acidosis –
lungs can not get enough 02
Acute problems
Pneumonia, airway obstruction, chest injuries
Drugs that depress the respiratory control center
Chronic respiratory acidosis
Common with COPD
Respiratory Alkalosis –
Blowing off too much C02
Hyperventilating
Caused by anxiety, high fever, overdose of aspirin
Head injuries
Brainstem tumor
Metabolic Acidosis – 3 D’s
- Excessive loss of bicarbonate (HCO3) ions to buffer hydrogen
- -Diarrhea―loss of HCO3 from intestines
2.Diabetic acidosis
3.Renal disease or failure Dialysis
Decreased excretion of acids
Decreased production of HCO3 ions
Metabolic Alkalosis
Increase in serum bicarbonate ion
- Loss of hydrochloric acid from stomach
- Hypokalemia
- Excessive ingestion of antacids
Effects of Acidosis
-Impaired nervous system function Headache Lethargy Weakness Confusion Coma and death
-Compensation
Deep rapid breathing
Secretion of urine with a low pH
Effects of Alkalosis
Increased irritability of the nervous system causes:
Restlessness Muscle twitching Tingling and numbness of the fingers Tetany Seizures Coma
Treatment of Imbalances
Treatment of underlying cause
Immediate corrective measures to include fluid and electrolyte replacement or removal
Caution is required when adjusting fluid levels to ensure appropriate electrolyte balance.
Addition of bicarbonate to the blood to reverse acidosis
Modification of diet to maintain better electrolyte balance
Hydrogen Ion and pH Scale
- 8= DEATH
- 35=ACIDOSIS AND INCREASE H+
- 4= NORMAL
- 45= ALKALOSIS AND DECREASE H+
- 8= DEATH
