Fluid, Electrolyte, & Acid-Base Balance PDF

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Fluid, Electrolyte, & Acid-Base Balance...

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Fluid, Electrolyte, & Acid-Base Balance Characteristics of Body Fluids o Fluid: water that contains dissolved/suspended substances such as glucose, mineral salts, & proteins o Volume: fluid amount o Osmolality: fluid concentration; # of particles per kg of water o Fluid composition: electrolyte concentration o pH: degree of acidity Scientific Knowledge Base: Location & Movement of Water & Electrolytes o Intracellular fluid (ICF): fluids w/in cells  2/3 of total body water o Extracellular fluid (ECF): fluid outside of cells  1/3 of total body water  Three divisions:  Interstitial: fluid between the cells & the outside of the blood vessels  Intravascular: liquid portion in our blood vessels (plasma)  Transcellular: fluid in the CSF, peritoneal, synovial Electrolytes & Ions o Electrolytes: mineral salts; compounds that separate into ions (charged particles) when they dissolve in water o Ions: charged particles  Cation: positively charged  Anion: negatively charged Movement of Water & Electrolytes o Active transport: movement of ions against osmotic pressure to an area of higher pressure; requires energy  Example: sodiumpotassium pump o Diffusion: passive movement of electrolytes or other particles down the concentration gradient (from higher to lower concentration) o Osmosis: movement of water (or other solute) from an area of lesser to 1 of greater concentration

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Filtration: movement across a membrane, under pressure, from higher to lower pressure

Fluid Balance o Consists of: fluid intake & absorption, fluid distribution, fluid output o Intake = output o Fluid intake: drinking & foods, thirst & habit  2300 mL/day  Document fluid intake for IV, rectal enema  Patients w/ neurological or psychological problems can have a decreased thirst mechanism = dehydration o Fluid distribution: movement of fluid among its various compartments  Extracellular & intracellular  Vascular & interstitial o Fluid output: usually via skin, lungs, GI tract, kidneys  Abnormally via vomiting, wound drainage, hemorrhage  Insensible loss: fluid loss you can't see (breathing, skin)  Sensible loss: fluid loss you can see (hemorrhage, massive wound drainage, vomiting, diarrhea)  Hormone influences:  Antidiuretic hormone (ADH): decreases urine output when body is dehydrated/increased fluid loss  Renin-angiotensin-aldosterone system (RAAS)  Atrial natriuretic peptides (ANPS) Fluid Imbalances o Extracellular fluid volume imbalances:  Extracellular fluid volume (ECV) deficit  Hypovolemia: decreased vascular volume & often is used when discussing ECV deficit  ECV excess o Osmolality imbalances  Hypernatremia: "water deficit"; hypertonic (high sodium)  Hyponatremia: "water excess"; hypotonic (low sodium) o Clinical dehydration = ECV deficit & hypernatremia combined Electrolyte Balance o Intake & absorption o Distribution: plasma concentrations of K+, Ca2+, Mg+, and phosphate (PI) are very low compared w/ their concentrations in cells & bone  Concentration differences are necessary for normal muscle & nerve function

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Output: urine, feces, & sweat or vomiting, drainage, & fistulas

Electrolyte Imbalances o Potassium (K+): hypokalemia & hyperkalemia o Calcium (Ca2+): hypocalcemia & hypercalcemia o Magnesium (Mg2+): hypomagnesemia & hypermagnesemia Acid-base Balance o Acid production, buffering, & excretion interplay to create balance o Acids release hydrogen (H+) ions; bases (alkaline substances) take up H+ ions o Degree of acidity is reported as pH o pH scale: 1.0 (very acidic) to 14 (very basic) o pH of 7.0 is neutral; normal arterial blood is 7.35-7.45 o Maintain pH w/in this normal range is very important for optimal cell function o Acid production  Carbon dioxide + water carbonic acid hydrogen ion + bicarbonate o Acid buffering: buffers are pairs of chemicals that work together to maintain normal pH of body fluids  Bicarbonate + hydrogen ion carbonic acid o Acid excretion systems: lung & kidneys  Lungs excrete carbonic acid  Kidneys excrete metabolic acids o Excretion of carbonic acid: when you exhale, you excrete carbonic acid in the form of CO2 & water o Excretion of metabolic acids: the kidneys excrete all acids except carbonic acid Acid-base Imbalances o Respiratory acidosis:  Arises from alveolar hypoventilation  Lungs unable to excrete enough CO 2  Excess carbonic acid in the blood decreases pH o Respiratory alkalosis:  Arises from alveolar hyperventilation  Lungs excrete too much CO2  Deficit of carbonic acid in the blood increases pH o Metabolic acidosis:  Arises from increase in metabolic acid or decrease in base (bicarbonate)  Kidneys unable to excrete enough metabolic acids, which accumulate in the blood  Results in decreased level of consciousness o Metabolic alkalosis:  Arises from direct increase in base (bicarbonate) or decrease in metabolic acid  Results in increased blood bicarbonate o Kidney/lung can't compensate for itself:  Kidneys compensate for respiratory imbalances  Respiratory system compensates for metabolic imbalances  These compensatory mechanisms don't correct the problem, but they assist the body in adapting  However, if the underlying condition isn't corrected, these compensatory mechanisms will fail

Fluid, Electrolyte, & Acid-Base Balance Nursing Knowledge Base o Use the scientific knowledge base in clinical decision making to provide safe, optimal fluid therapy o Apply knowledge or risk factors for fluid imbalances & physiology of normal aging when assessing older adults, knowing that this age group is @ high risk for fluid imbalances o Ask ?s to elicit risk factors for fluid, electrolyte, & acid-base imbalances o Perform clinical assessments for signs & symptoms of these imbalances Nursing Process: Assessment o Nursing history:  Age: very young & old @ risk  Environment: excessively hot  Dietary intake: fluid, salt, foods rich in potassium, calcium, & magnesium (ability to chew & swallow)  Lifestyle: alcohol intake history (cause hypomagnesium)  Meds: include OTC & herbal, in addition to prescription meds, antacids (cause a high sodium content), laxatives (diarrhea = electrolyte problems) o Medical history:  Recent surgery (physiological stress, increases the release of aldosterone, glucocorticoids, & ADH)  GI output  Acute illness/trauma  Respiratory disorders (any illness that causes the patient to retain carbon dioxide will cause respiratory acidosis)  Burns  Trauma  Chronic illness  Cancer (side effects of chemo = nausea, vomiting, malnutrition)  Heart failure (decreased cardiac output, kidneys perfusion declines, urine output is decreased)  Oliguric renal disease (kidneys don't make any urine) o Physical assessment:  Daily weights: most accurate way in the hospital to assess fluid changes in a patient  Indicator of fluid status  Use same conditions (scale, time of day, clothes)  Fluid I&O  24-hour I&O: compare intake vs. output  Intake includes all liquids eaten, drunk, or received through IV  Output = urine, diarrhea, vomitus, gastric suction, wound drainage  Laboratory studies Nursing Diagnosis o Decreased cardiac output o Acute confusion o Impaired gas exchange o Impaired oral mucous membrane o Risk for electrolyte imbalance o Ineffective tissue perfusion o Impaired skin integrity

Fluid, Electrolyte, & Acid-Base Balance o o o o

Deficient fluid volume Excess fluid volume Risk for injury Deficient knowledge regarding disease management

Nursing Planning o Goals & outcomes o Setting priorities o Collaborative care Nursing Implementation o Health promotion  Fluid replacement education  Teach patients w/ chronic conditions about risk factors & signs & symptoms of imbalances o Acute care  Enteral replacement of fluids  Restriction of fluids  Parenteral replacement of fluids & electrolytes  Total parenteral nutrition (give nutrition through IV)  Crystalloids (electrolytes)  Colloids (blood & blood components) o Restorative care  Home intravenous therapy  Nutrition support  Medication safety (meds, OTC drugs, herbal preparations) IV Therapy o Crystalloids (anything w/ an electrolyte component, regular IV fluids) o Colloid (blood component) o Types of solutions: isotonic, hypotonic, hypertonic o Caution: too rapid or excessive infusion or any IV fluid has potential to cause serious problems o Vascular access devices o Initiation:  Equipment: vascular access devices (VADS), tourniquets, clean gloves, dressings, IV fluid containers, various types of tubing, & electronic infusion devices (EIDS), also called infusion pumps  Initiating the intravenous line  Regulating the infusion flow  Electronic infusion devices (EIDS/IV pumps)  Nonelectronic volume control devices  Maintaining the system (keeping system sterile & intact)  Changing intravenous fluid containers, tubing, & dressings  Assist patient w/ self-care activities  Complications:  Fluid overload: IV solution infused too rapidly or in too great of an amount  Infiltration: IV fluid entering subcutaneous tissue around venipuncture site; tight skin around IV site, blanched skin, cool to the touch

Fluid, Electrolyte, & Acid-Base Balance Extravasation: technical term used when vesicant (tissuedamaging) drug enters tissues  Phlebitis: inflammation of inner layer of a vein; redness, tenderness, pain, warmth along the vein, streaking  Local infection: infection @ catheter-skin entry point during infusion or after removal of IV catheter  Bleeding @ the infusion site: oozing/slow, continuous seepage of blood from venipuncture site  Discontinuing peripheral IV access CDC recommends IV tubing that is used for continuous infusions gets changed every 96 hours unless there is a problem w/ contamination CDC recommends piggyback tubing gets changed every 24 hours 

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Nursing Interventions o Interventions for electrolyte imbalances:  Support prescribed medical therapies  Aim to reverse the existing acid-base imbalance  Provide for patient safety o Interventions for acid-base imbalances:  Arterial blood gases...