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NURS 2090 (20)
Lecture

Altered Fluid.docx

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Department
Nursing
Course
NURS 2090
Professor
Heather Helpard
Semester
Fall

Description
Altered Fluid, Electrolyte and Acid-Base Balance Fluid, Electrolytes and Acid-Base Balance  Water and electrolyte intake and output are regulated through hormonal and neural interactions  Most metabolic processes in the body result in the production of acid  Acid is removed through the lungs (CO2) and kidney (acid/base balanc)***EXAM QUESTION!!! Distribution of Ions Chlorine usually follows Na+ Think of electrolyte imbalance if you see: Interstitial fluid (ISF) (OUTSIDE CELL) -edema - high Na, Cl, Ca - cognition changes - low K, Mg, P - breathing problems - med HCO3 -diarrhea/vomiting -massive burns/ blood loss Intracellular Fluid (ICF) (INSIDE CELL) -arrhytmias - high K -muscle cramps - low Ca, Na, HCO3, Cl Caution: Diuretics and BP meds can create - mod P, Mg an electrolyte imbalance 3 Na out to ECF/ 2 K in, which goes against the concentration gradient (since Na+/K ATPase requires energy) makes sense why the fluid INSIDE the cell has higher K. (Potassium is pumped inside AGAINST the concentration gradient. 2 inside-- when if there was no energy it would want to leak out due to the concentration gradient). Sodium-Potassium Pump Altered Sodium Balance - Aldosterone is used for sodium balance. It helps reabsorb Na + water (while excreting K+). Hyponatremia - Decreased levels of sodium in the blood (less than 135mEq/L) - Can be caused by excessive Sweating, Vomiting/Diarrhea, cirrhosis (i.e. a long distance runner). Need to intake electrolytes/sodium because if you just drink water, you will only dilute the salt even more. ** limit intake of water Clinical Manifestations:  Muscle effects: (↑depolarization)  Muscle twitching & weakness  Reduced extracellular circulating volume leads to:  Hypotension  Tachycardia (↑ HR reflex tachycardia)  Oliguria: Reduced urine output – body tries to retain Na+  Anuria: absent urine output – body tries to retain Na+  Altered Neuronal FX leads to (this is due to the fact that there can be cerebral edema, increasing intercranial pressure) brain swelling causes most of the symptoms!  Nausea + vomiting  Seizures  *Lethargy  coma  *Confusion * means one of the first signs Hypovolemic hyponatremia- Total body water (TBW) decreases; total body sodium (Na ) decreases to a greater extent. The extracellular fluid (ECF) volume is decreased. Hypervolemic hyponatremia-Total body sodium increases, and TBW increases to a greater extent. The ECF is increased markedly, with the presence of edema. Hypernatremia-Increased levels of sodium in the blood (over 145mEq/L) - Caused by excess sodium intake or loss of body water. - Think about DEHYDRATION SYMPTOMS Clinical Manifestations:  Altered cell metabolism causes:  Irritation  Restlessness  Decreased LOC  Fluid shifts cause:  Thirst- need water to dilute (↓ concentration)  Hypertension (↑ Na linked to HTN)  Tachycardia Altered Potassium Balance Explanation: - cannot wait on this test- CRITICAL VALUES! -has an 80% filtration rate through the kidney (aldosterone= hormone regulator) -Any time there is sodium- potassium membrane disturbance, it will lead to muscle cramps + weakness - Potassium is needed for cardiac function and skeletal/smooth muscle contraction Hypokalemia- Potassium levels of less than 3.5mEq/L in the blood - Caused by diuretics, severe vomiting and diarrhea Lower potassium levels in the extracellular space will cause hyperpolarization of the resting membrane potential. This hyperpolarization is caused by the effect of the altered potassium gradient on resting membrane potential. As a result, a greater than normal stimulus is required for depolarization of the membrane in order to initiate an action potential. - In the heart, hypokalemia causes hyperpolarization in the myocytes' resting membrane potential. The more negative membrane potentials in the atrium may cause arrhythmias because of more complete recovery from sodium-channel inactivation, making the triggering of an action potential more likely. In addition, the reduced extracellular potassium (paradoxically) inhibits the activity potassium current and delays ventricular repolarization. This delayed repolarization may promote reentrant arrhythmias. Clinical Manifestations:  Hypotension  Dizziness (↓BP causes this)  Cardiac Arrhythmias- life threatening  Muscle Effects:  Muscle Weakness +Leg Cramps, which cause:  Nausea  Anorexia (loss of appetite)  Abdominal Distention  Polyuria + poorly concentrated urine Hyperkalemia- Potassium levels of more than 5.0mEq/L in the blood - Is Iatogenic, due to drugs or renal failure (not excreting enough), trauma - is a precursor to MI - Increased extracellular potassium levels result in depolarization of the membrane potentials of cells. This depolarization opens some voltage-gated sodium channels, but not enough to generate an action potential. After a short while, the open sodium channels inactivate and become refractory, increasing the threshold needed to generate an action potential. This leads to the impairment of neuromuscular, cardiac, and gastrointestinal organ systems. Of most concern is the impairment of cardiac conduction which can result in ventricular fibrillation or asystole. Clinical Manifestations:  Altered membrane potential causes:  Cardiac arrest  abdominal cramping  flaccid paralysis – loss of muscle tone (because of effect on Na channels)  Edema Altered Chloride Balance -follows sodium Hypochloremia- When blood levels are less than 98mEq/L - Usually occurs as a result of hyponatremia, hypokalemia and metabolic alkalosis - Caused by vomiting, diarrhea, diuretics Metabolic Alkalosis Reasoning: Due to volume depletions, the chloride level decreases. Hence, the kidneys retain the bi-carbonate and sodium ions for balancing the incurred loss. As a result, bicarbonate accumulates in the ECF, thereby raising the pH level leading to hypochloremic metabolic alkalosis. ** this explains the shallow, depressed breathing Clinical Manifestations:  Muscle effects:  Excessive Tone/Tetany  Weakness And Twitching  Shallow Depressed Breathing (metabolic alkalosis)  Paralysis  Mental Confusion Hyperchloremia- When blood levels are more than 108mEq/L - Caused by dehydration, kidney failure, brain trauma - Associated With Metabolic Acidosis Metabolic Acidosis Reasoning: a decrease in plasma bicarbonate concentration, and in an increase in plasma chloride concentration. Acidosis is associated with ↑ Breathing. Clinical Manifestations:  Muscle Effects:  Deep Rapid Breathing (acidosis)  Weakness  Headache  Diminished Cognitive Ability  Cardiac Arrest Altered Calcium Balance Explanations: - Release of calcium is controlled by the parathyroid gland, important for vit D absorption and muscle contraction and enzymes - There is evidence that the parathydroid gland effects mood- so its no surprise that hyper/ hypo cause irritability and depression. The key difference is that Hypo = anxiety, whereas Hyper= psychotic effects, like confusion/delirium. - Calcium is involved in muscle contraction. When there is low Ca in the blood, the system is actually more excitable; thus, leading to twitches, cramps, tenany, etc. (Decreased Ca increases the likelihood of an action potential = twitches. However, Increased Ca causes weakness because muscles are LESS LIKELY to depolarize.). - Cardiac Arrhythmia is associated with hypo/hyper, as you need balance for proper contraction Hypocalcemia- Calcium blood levels of less than 8.5mg/dL - Caused by Vit D deficiency, menopause (loss of estrogen), osteoporosis, heparin/glucagon, thyroid, burns, kidney failure Clinical Manifestations:  Hypotension- due to ↓ Blood volume  Mood changes (Anxiety, Irritability, depression)  Muscle Effects:  Twitching/Cramps/Spasms  Tetany- involuntary contraction of muscles  Laryngospasm- ↑ contraction in the voice box (life threatening)  Seizure- due to ↑excitability in the brain  Cardiac Arrhythmia Hypercalcemia- Calcium blood levels of more than 10.5mg/dL - Caused by excessive bone break down, thyroid disease, intake of Ca Clinical Manifestations:  Mood changes (Delirium/ Confusion, irritability) (also due to ↓ firing of muscles)  Nausea And Vomiting (due to ↑ Gastric sections)  Headaches (made worse by vomiting)  Muscle Effects: (due to ↓ firing of muscles)  Weakness  Constipation- due to decreased muscle contractions in GI/ dehydration  Fatigue  Cardiac Arrhythmia Altered Magnesium Balance Explanation: - Magnesium is needed for almost all biochemical mechanisms: DNA and Protein synthesis, oxidative phosphorylation, mitochondrial respiration. - Magneisum is an effective Calcium Channel Blocker (CCB), and it can block cardiac K+ channels. - Is a known cause of hypotension and cardiac dysfunction. - Preeclampsia needs mg infusions - Magnesium’s role in the balance of sodium and potassium is that of an intermediary. Potassium is unable to cross the cell membrane on its own, and requires magnesium to unlock the door for its entrance. Once the cell membrane is open, the cell can absorb all of the potassium it needs for a proper balance. (thus, low mg means less K absorption and more excretion). - There are concurrent effects between Mg and Ca, K, Na Hypomagnesemia- Blood levels less than 1.5mEq/L -Caused by malnutrition, malabsportion syndromes, burns, alcoholism - lack of Mg depolarizes the heart! Clinical Manifestations:  Hypotension (due to ↓BV)  Occurs With Hypocalcemia (because ↑ elimination of Ca) And Hypokalemia (because it ↑elimination of K+)  Muscle Effects : (due to increased depolarization, muscle excitation)  Tetany  Muscle Cramping  Seizures  Cardiac Arrhythmias Hypermagnesemia- Blood levels more than 2.5mEq/L - linked with renal failure/dialysis, or excessive intake Clinical Manifestations:  Hypotension  Muscle effects: (due to ↓ depolarizations of muscles)  Diminished Reflexes  Muscle Weakness  Flaccid Paralysis  Respiratory Depression  Decreased sodium movement causes:  Cardiac Arrhythmia  Bradycardia (because its an effective CCB and blocks K channels in the heart) Altered Phosphate Balance - has a relationship with calcium Explanation: Phosphate is the most abundant intracellular anion and is essential for membrane structure, energy storage, and transport in all cells. In particular, phosphate is necessary to produce ATP, which provides energy for nearly all cell functions. Phosphate is an essential component of DNA and RNA. Phosphate is also necessary in red blood cells for production of 2,3-diphosphoglycerate (2,3-DPG), which facilitates release of oxygen from hemoglobin. - Approximately 85% of the body's phosphorus is in bone as hydroxyapatite, while most of the remainder (15%) is present in soft tissue. Hypophosphatemia- Blood levels less than 2.5mg/dL - A
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