Copyright © 2013, 2010, 2006, 2002 by Saunders, an imprint of Elsevier Inc. C HAPTER 13 Assessment and Care of Patients with Fluid and Electrolyte Imbalances

Copyright © 2013, 2010, 2006, 2002 by Saunders, an imprint of Elsevier Inc. H OMEOSTASIS Proper functioning of all body systems; requires fluid and electrolyte balance Extracellular fluid Intracellular fluid Interstitial fluid Transcellular fluids

Copyright © 2013, 2010, 2006, 2002 by Saunders, an imprint of Elsevier Inc. F ILTRATION Movement of fluid through cell or blood vessel membrane because of differences in water volume pressing against confining walls

Copyright © 2013, 2010, 2006, 2002 by Saunders, an imprint of Elsevier Inc. H YDROSTATIC P RESSURE “Water-pushing pressure” Force that pushes water outward from a confined space through a membrane Amount of water in any body fluid space determines pressure

Copyright © 2013, 2010, 2006, 2002 by Saunders, an imprint of Elsevier Inc. C LINICAL S IGNIFICANCE : B LOOD P RESSURE Example of hydrostatic filtering forces, moving whole blood from the heart to capillaries where filtration occurs to exchange water, nutrients, and waste products between the blood and tissues

Copyright © 2013, 2010, 2006, 2002 by Saunders, an imprint of Elsevier Inc. C LINICAL S IGNIFICANCE : E DEMA Develops with changes in normal hydrostatic pressure differences

Copyright © 2013, 2010, 2006, 2002 by Saunders, an imprint of Elsevier Inc. C LINICAL S IGNIFICANCE : D IFFUSION Free movement of particles (solute) across permeable membrane from area of higher to lower concentration Important in transport of most electrolytes; other particles diffuse through cell membranes Sodium pumps Glucose cannot enter most cell membranes without help of insulin

Copyright © 2013, 2010, 2006, 2002 by Saunders, an imprint of Elsevier Inc. C LINICAL S IGNIFICANCE : O SMOSIS & F ILTRATION Act together at capillary membrane to maintain normal ECF and ICF volumes Thirst mechanism is example of how osmosis helps maintain homeostasis Feeling of thirst caused by activation of brain cells responding to changes in ECG osmolarity

Copyright © 2013, 2010, 2006, 2002 by Saunders, an imprint of Elsevier Inc. F LUID B ALANCE Closely linked to/affected by electrolyte concentrations Fluid intake Fluid loss Minimum urine amount needed to excrete toxic waste products = 400 to 600 mL Insensible water loss – through skin, lungs, stool

Copyright © 2013, 2010, 2006, 2002 by Saunders, an imprint of Elsevier Inc. H ORMONAL R EGULATION OF F LUID B ALANCE Aldosterone Antidiuretic hormone Natriuretic peptides

Copyright © 2013, 2010, 2006, 2002 by Saunders, an imprint of Elsevier Inc. S IGNIFICANCE OF F LUID B ALANCE : R ENIN -A NGIOTENSIN II P ATHWAY Blood (plasma) volume and intracellular fluid most important to keep in balance Kidneys are major regulator of water and sodium balance; maintain blood and perfusion pressure to all tissues/organs When the kidneys sense a low parameter, they secrete renin

Copyright © 2013, 2010, 2006, 2002 by Saunders, an imprint of Elsevier Inc. C LINICAL A PPLICATION Renin-angiotensin II pathway is greatly stimulated with shock, or when stress response is stimulated Patients with hypertension often take ACE inhibitors

Copyright © 2013, 2010, 2006, 2002 by Saunders, an imprint of Elsevier Inc. ACE I NHIBITORS Disrupt renin-angiotensin II pathway by reducing amount of ACE produced With less angiotensin II, less vasoconstriction and reduced peripheral resistance Greater excretion of water and sodium in urine By locking angiotensin II receptors, blood pressure lowers

Copyright © 2013, 2010, 2006, 2002 by Saunders, an imprint of Elsevier Inc. D EHYDRATION Fluid intake/retention does not meet body’s fluid needs; results in fluid volume deficit Consideration for older adults

Copyright © 2013, 2010, 2006, 2002 by Saunders, an imprint of Elsevier Inc. D EHYDRATION : C OLLABORATIVE C ARE Assessment History Physical assessment/clinical manifestations: Cardiovascular Respiratory Skin Neurologic Renal

Copyright © 2013, 2010, 2006, 2002 by Saunders, an imprint of Elsevier Inc. F ACTS TO R EMEMBER... 1 L of water weighs 2.2 lb, equal to 1 kg Weight change of 1 lb = fluid volume change of about 500 mL

Copyright © 2013, 2010, 2006, 2002 by Saunders, an imprint of Elsevier Inc. F LUID O VERLOAD Excess of body fluid “Overhydration”

Copyright © 2013, 2010, 2006, 2002 by Saunders, an imprint of Elsevier Inc. F LUID O VERLOAD : C OLLABORATIVE C ARE Assessment Patient safety Pulmonary edema Drug therapy Nutrition therapy Monitoring of I&O

Copyright © 2013, 2010, 2006, 2002 by Saunders, an imprint of Elsevier Inc. E LECTROLYTE I MBALANCE Can occur in healthy people as result of changes in fluid intake and output Can be life threatening if severe; can occur in any setting

Copyright © 2013, 2010, 2006, 2002 by Saunders, an imprint of Elsevier Inc. C ONSIDERATIONS FOR O LDER A DULTS At risk for most electrolyte imbalances from age- related organ changes Have less total body water than younger adults; more at risk for fluid imbalances; more likely to be taking drugs affecting fluid or electrolyte balance

Copyright © 2013, 2010, 2006, 2002 by Saunders, an imprint of Elsevier Inc. S ODIUM Normal level: mmol/L “Where sodium goes water follows” Hyponatremia Hypernatremia

Copyright © 2013, 2010, 2006, 2002 by Saunders, an imprint of Elsevier Inc. P OTASSIUM Normal level: mEq/L Some control over intracellular osmolarity and volume Regulate protein synthesis, glucose use and storage Hypokalemia Hyperkalemia

Copyright © 2013, 2010, 2006, 2002 by Saunders, an imprint of Elsevier Inc. C ALCIUM Normal level: mg/dL Absorption requires active form of vitamin D Stored in bones Parathyroid hormone Thyrocalcitonin Hypocalcemia Hypercalcemia

Copyright © 2013, 2010, 2006, 2002 by Saunders, an imprint of Elsevier Inc. H YPOCALCEMIA

Copyright © 2013, 2010, 2006, 2002 by Saunders, an imprint of Elsevier Inc. P HOSPHORUS Normal level: mg/dL Found in bones Activates vitamins and enzymes; assists in cell growth and metabolism Plasma levels of calcium and phosphorus exist in a balanced reciprocal relationship Hypophosphatemia Hyperphosphatemia

Copyright © 2013, 2010, 2006, 2002 by Saunders, an imprint of Elsevier Inc. M AGNESIUM Normal level: 1.3 to 2.1 mg/dL Critical for skeletal muscle contraction, carbohydrate metabolism, ATP formation, vitamin activation, cell growth Hypomagnesemia Hypermagnesemia

Copyright © 2013, 2010, 2006, 2002 by Saunders, an imprint of Elsevier Inc. C HLORIDE Normal level: 98 to 106 mEq/L Imbalance occurs resulting from other electrolyte imbalances Treat underlying electrolyte imbalance or acid-base problem

Copyright © 2013, 2010, 2006, 2002 by Saunders, an imprint of Elsevier Inc. C HAPTER 13 Audience Response System Questions 28

Copyright © 2013, 2010, 2006, 2002 by Saunders, an imprint of Elsevier Inc. Q UESTION 1 While monitoring a patient who has fluid overload, the nurse would be most concerned about which assessment finding? A.Pitting edema in the feet B.Neck vein distention C.Bounding pulse D.Presence of crackles in the lungs

Copyright © 2013, 2010, 2006, 2002 by Saunders, an imprint of Elsevier Inc. Q UESTION 2 A patient has been having frequent liquid diarrhea for the last 24 hours. A stool sample was sent to the laboratory to confirm whether the patient has a Clostridium difficile infection. The nurse should monitor the patient for which electrolyte imbalance? A. Hypokalemia B. Hyponatremia C. Dehydration D. Hypocalcemia

Copyright © 2013, 2010, 2006, 2002 by Saunders, an imprint of Elsevier Inc. Q UESTION 3 A 25-year-old student has been taken to an urgent care clinic because of dehydration. She says she has had “the flu,” with vomiting and diarrhea “all night” and admits that she has had very little to eat or drink. She now says the GI symptoms have subsided but she feels weak. The nurse expects which type of rehydration to occur? A.Oral rehydration therapy with water B.Oral rehydration therapy with a solution containing glucose and electrolytes C.Oral rehydration therapy with tea D.IV fluid replacement