Fluid and Electrolyte Imbalances

What is causes Capillary Hydrostatic Pressure push?
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What is causes Capillary Hydrostatic Pressure push?
Hydrostatic pressure (30 mmHg) is higher than ontoctic pressure on the arterial end, resulting in fluid being pushed into the interstitial space.
What occurs in Imbalance due to Decreased Capillary Colloid Ostmotic pressure?
Lack of pressure to pull fluid into the vessel at the venous end of the capillary.
What does an interstitial fluid pressure of -3 mmHg result in?
Interstitial fluid pressure is about -3 mmHg and this negative pressure facilitates the movement of fluid from the capillary to the interstitial space
What causes Capillary Colloid Osmotic Pressure pull?
Capillary Colloid Osmotic pressure is 28 mmHg at the arterial end of the capillary. At the venous end, much of the solutes and especially the plasma proteins, remain in the capillaries, resulting in capillary ostmotic pressure pulling fluid back from the interstitial space in to the vessel.
What does an interstitial colloid osmotic pressure of 8 mmHg result in?
This positive pressure in the interstitial space results in the movement of fluid from the vessel into the interstitial space (pressure is caused by the proteins in the interstitial space).
What is the role of the Lymph vessel in Capillary Fluid balance?
Excess interstitial fluid is taken from the tissues into the lymph vessels and then returned to central circulation.
What determines Capillary Fluid Balance?
The push and pull of the pressure across the semi permeable membrane of the capillary. This membrane must have good integrity to be effective.
What occurs in Imbalance due to Increased Capillary Hydrostatic Pressure?
An increase in amount of fluid leaving the capillaries (hydrostatic pressure is increased even at the venous end of the vessel). A sufficient increase result in a net fluid movement out of the capillary.
Source of Imbalance due to Increased Capillary Hydrostatic Pressure: Increased fluid pressure due to...
Hypertension
Source of Imbalance due to Increased Capillary Hydrostatic Pressure: Increased fluid volume due to...
Na+ and H2O retention
Source of Imbalance due to Increased Capillary Hydrostatic Pressure: Back up of blood flow due to...DVT (venous blockage leading to increased pressure at the venous end of the capillary)What occurs in Imbalance due to Decreased Capillary Colloid Osmotic Pressure?Lack of pressure to pull fluid into the vessel at the venous end of the capillary.Source of Imbalance due to Decreased Capillary Colloid Ostmotic pressure: Low serum albumin levels causes...Decrease in colloid pressure. Low albumin levels may be due to burns, liver damage, disease malnutrition, excessive wound drainage...etc.What causes Imbalance in Increased Interstitial Colloid Osmotic Pressure?Increased colloid osmotic pressure results in movement. Solutes escape from the vessel and move to the interstitial fluid, which holds the fluid in the interstitial space.Source of Imbalance in Increased Interstitial Colloid Osmotic Pressure: Leaky capillaries lead to...Freer movement of fluids and solutes across the capillary membrane. Faulty Capillaries may be due to intentional change or natural processes such as inflammation.Source of Imbalance in Tissue Hydrostatic Pressure: Obstruction of Lymph Flow leads to...(Lymphedema): Creates increased interstitial colloid osmotic pressure. Pressure in the tissue forces fluid into the vessel, but this also pushes fluid into the tissue. Obstruction may be due to liver disease or due to physical obstruction due to surgery. Overall, fluid accumulates in the tissues.Sources of Edema: Increased capillary permeability leads to...Loss of intravascular proteinsSources of Edema: Lymphatic obstruction leads to...Decreased absorption of interstitial fluidSources of Edema: Increased Capillary Hydrostatic pressure leads to...Fluid movement into tissuesSources of Edema: Decreased plasma protein production leads to...Decreased capillary oncotic pressure (fluid remains in the interstitial space)Edema Vs. Third spacing: What is the difference between them?Edema is insterstitial fluid accumulation Third spacing is transcellular fluid accumulationThird Spacing: Transcellular fluid accumulation: where does it occur?This is a smaller subdvision of the extracellular fluid compartment and consists of various paces including joint capsules, pericardial and pleural cavities and the peritoneum and ocular fluids.Third Spacing: Transcellular fluid accumulation: what is it?Fluid is essentially trapped and cannot engage in exchange with the rest of the ECF. Called non functional fluid.Manifestations of Edema: Brain: Causes and consequencesCommonly associated with infections or trauma resulting in an inflammatory response which leads to an increase in intercranial pressure, resulting in head ache, coma, altered level of consciousness, abnormal pupil size, abnormal reflexive response, changes in respiration and muscle tone, and abnormal posturing.Manifestations of Edema: Airway: Causes and consequencesEspecially when around the alveoli. Leads to a drop in gas exhange and ability of the lungs to inflate. Causes and location of the fluid shift affects the manifestation, but always includes dyspnea. Pt may also have anxiety or restlessness, decreased breath sounds or crackles on auscultation.Manifestations of Edema: Intestine: Causes and whereInside the lumen and walls of the intestine. May be caused by intestinal obstruction.Manifestations of Edema: Abdomen: Causes, where, and consequencesFluid in the peritoneal cavity (acities). May be caused by increased hydrostatic pressure due to portal vein obstruction (such as in liver chirrohsis or inflammation in response to an issues such as a tumor or pancreatitis). May cause shortness of breath (due to restriction of movement of the diaphragm), increased abdominal girth and protruding umbilicus.Manifestations of Edema: Peripheral Edema: Causes, where (depends on patient condition) and consequences Effects of salt retentionOften due to venous obstruction which increases hydrostatic pressure or due to obstruction of lymphatic drainage. Often occurs in the lower extremities in the ambulatory patient and in the sacral area in bedridden patients (often called dependent edema). Note that apparent edema really on occurs with significant fluid accumulation. Salt retention usually result in pitting edema.Treatment of edema: starts with...Identifying the source of the problem.Treatment of edema: Diuretic pressureTo treat patients with HTNTreatment of edema: Supportive measuresie. in treating pregnant women with peripheral edema, you may want to limit the amount of time she spends on her feet. ie. Pt with heart failure may wear supportive stockings to resist movement of fluid from the capillary to the interstitial space.Maintaining Na+ and H2O Balance...role of Na+ and H2O balanceECF levels of water and sodium and maintaining vascular volume. Na+ and H2O affect the movement of fluid between in the intracellular and extracellular fluid compartments.Mechanisms for maintaining Na+ and H2O Balance (5)Thirst, ADH (Vasopressin), Sympathetic NS, RAAS, and Natiuretic peptides. Receive signals from the osmo and baro receptors.Fluid balance receptors: OsmoreceptorsIn the hypothalamus; monitor the osmolality of the blood (Na is the predominant osmotically active particle in the blood).Fluid balance receptors: BaroreceptorsIn the blood vessels around the heart and kidneys; measure stretch of the vessels produced by blood volume and blood pressure.Mechanism for the maintenance of Na+ and H2O: Thirst and ADHSudden drops in blood volume or an increase in osmolality will trigger the thirst mechanism. ADH is from the hypothalamus and stored in the post. pit. Low blood vol or increased in osmolality results in the release of ADH from the post. pit, which causes the kidneys to retain fluid.Mechanism for the maintenance of Na+ and H2O: Sympathetic nervous system: GFRRegulates the conctriction or relaxation of the afferent and efferent arterioles in the kidneys = control of the amount of filtrate produced. ie. constriction of the afferent vessel limits blood flow to the kidney, reducing GFR.Mechanism for the maintenance of Na+ and H2O: Sympathetic nervous system: Tubular ResistanceRegulation of Na reabsorption.Mechanism for the maintenance of Na+ and H2O: Sympathetic nervous system: Renin releaseDue to Sympathetic NS stimulation.Mechanism for the maintenance of Na+ and H2O: RAASA drop in circulating blood volume decreases the amount of renal perfusion pressure. reduced stretch of the afferent arteriole is detected by the juxtaglomerular cells in the kidneys, resulting in the release of renin, which converts angiotensinogen to angiotensin I, which is converted by ACE into angiotensin II, which result in Na reaborption in the kidneys and aldosterone release resulting in promotoion of the exchange of Na and K (Na is reabsorbed and K is lost). The end result is water retention.Mechanism for the maintenance of Na+ and H2O: Natriuretic Peptides: ANP and BNPRespond to increased blood pressure/volume. Counter-regulatory: encourage the excretion of Na+ and water by suppressing renin level, decreasing aldosterone levels and causing vasodilation. Counter balance the activity of baroreceptors.Populations at risk for fluid imbalance: InfantsHave a higher percentage of water than adults and more water in the extracellular component (more than half). They also ingest and excrete a relatively higher volume of water compared to adults, resulting a smaller reserve of water than adults. Infant kidneys are also not as efficient in concentrating urine, their hemostatic regulating systems are not as efficient (in responding to small changes in fluid balance) and infants lose more fluid through their skin due to an increase in proportional body surface area.Populations at risk for fluid imbalance: ElderlyAging kidneys decrease gloermuli (#) and GFR, in all, resulting in a loss of ability to concentrate urine. They also have a slowed response to changes in Na and water level changes and decreased response to ADH and decreased secretion of aldosterone. In all, there is a reduction in body water. Thirst sensation is also decreased and water intake is mostly limited to food intake. Eating poorly and suffering from malnutrition and dehydration is common.Populations at risk for fluid imbalance: ObeseFluid imbalance caused by an overall decrease in overall total body water percentage, resulting in a decreased tolerance for changes of any kind.Populations at risk for fluid imbalance: IllMay be linked to decreased intake or increased output or inflammatory response resulting in intravascular fluid loss (can result in dehydration).Assessing Fluid Balance: Thirst, mucous membranes, turgor, tearingThirst is an indicator of imbalance. Mucous membranes will be dry (such as in the mouth). There is a loss of skin turgor (skin elasticity) (but this is not always a good indicator, especially in older adult pts. Obese individuals and infants may maintain skin turgor even when in a state of dehydration. Tearing is a reliable indicator in children for volume deficit.Assessing Fluid Balance: Pulse and BPTachycardia is usually the 1st sign of drop in vascular volume. Change in pulse rate, regularity and volume are present in several types of fluid and/ or electrolyte imbalances. BP can indicate balance and should be checked when going from sitting to standing.Assessing Fluid Balance: EdemaNot apparent until interstitial volume has increased by at least 2.5 L. Need to assess if edema is generalized, local, dependent as well as assessing for manifestations of pulmonary edema (ie. auscultate for crackles) and the accumulation of fluid in the peritoneum (ie. third spacing, increasing in abdominal girth).Assessing Fluid Balance: WeightSudden drops in weight are indicative of fluid loss.Assessing Fluid Balance: Intake/ Output; urine concentrationNormal output in an adult is 1000 - 2000 mL/ day or 40 - 80 mL. Should be monitored regularly; keep in mind other ways of losing fluids. Urine concentration (specific gravity) gives a measure of the kidneys' function. Note that specific gravity can be affected by glucose and albumin.Assessing Fluid Balance: Neuromuscular signsElectrolyte and fluid imbalances can result in the central and peripheral effects including headache, anxiety, and changes in level of consciousness and twitching linked to specific deficits.Disorders if Na+ and H2O Balance: Proportionate changes in water and sodiumIsotonic changes (Note that Na is associated with chloride and/ or bicarbonate anions and the most accountable for the osmotic activity in the ECF).Disorders if Na+ and H2O Balance: Disproportionate changes in water and sodiumAlteration in normal concentrationsDisorders if Na+ and H2O Balance: Isotonic Fluid Volume Deficit: Causes: Inadequate intake due to...Potable fluids are unavailable or the thirst mechanism is impaired. Note that the concentrations of electrolytes remain normal but fluid volume has decreased.Disorders if Na+ and H2O Balance: Isotonic Fluid Volume Deficit: Causes: Excessive output due to...Loss through skin (ie. due to fever, burns), third spacing, GI tract (resulting in issues in reabsorption), and the kidneys. Again, note that the concentrations of electrolytes remain normal but fluid volume has decreased.Disorders if Na+ and H2O Balance: Isotonic Fluid Volume Deficit: Manifestations: Thirst(Maybe). Normally it is a response to even small changes in volume, but may not be reliable in the elderly and in infants.Disorders if Na+ and H2O Balance: Isotonic Fluid Volume Deficit: Manifestations: Weight loss(Maybe). 1L = 1kg. Deficit does not always means weight loss (ie. in third spacing).Disorders if Na+ and H2O Balance: Isotonic Fluid Volume Deficit: Manifestations: Decreased Urine output and increased SG and osmolalityDecreased in vascular volume is sensed by baroreceptors = secretion of ADH as a compensatory mechanism, resulting in decreased urine output.Disorders if Na+ and H2O Balance: Isotonic Fluid Volume Deficit: Manifestations: Sunken eyes and loss of skin turgorLinked to more movement of the fluid from the interstitial space to the vasculature as a compensatory mechanism. Note always applicable as you naturally lose skin elasticity and depending on status of body.Disorders if Na+ and H2O Balance: Isotonic Fluid Volume Deficit: Manifestations: TearingIn infants.Disorders if Na+ and H2O Balance: Isotonic Fluid Volume Deficit: Manifestations: Changes in blood pressure and changes in pulse (consider postural hypotension)Postural hypotension is a common early sign of fluid deficit and drop in BP. Note increase in HR, pulse becomes weak and thready. Hypovolemic shock and vasculature collapse occur due to severe fluid deficit.Disorders if Na+ and H2O Balance: Isotonic Fluid Volume Deficit: Manifestations: Hct and BUNDrop in Na and H2O results in increased RBC and BUN concentration.Disorders if Na+ and H2O Balance: Isotonic Fluid Volume Deficit: TreatmentReplace the fluid and treat the cause. This needs to be done promptly to avoid renal damage and circulatory collapse in the case of hypovolemia.Disorders if Na+ and H2O Balance: Isotonic Fluid Volume Excess: Causes and consequencesInadequate elimination and excessive intake. HCP can accidentally induce this state of hypervolemia when IV therapy is given too quickly or too much is given and the body is unable to adapt to the change in volume. Can result in issues in pumping action of the heart, leading to decreased blood flow, especially to the kidneys, leading to fluid retention.Disorders if Na+ and H2O Balance: Isotonic Fluid Volume Excess: Manifestations: Weight gainEspecially over a short period of time.Disorders if Na+ and H2O Balance: Isotonic Fluid Volume Excess: Manifestations: Edema (due to?)Due to increase in hydrostatic pressure.Disorders if Na+ and H2O Balance: Isotonic Fluid Volume Excess: Manifestations: Distended neck veins and bounding pulseDue to increase in vasculature volume.Disorders if Na+ and H2O Balance: Isotonic Fluid Volume Excess: Manifestations: Respiratory symptoms (ie. on auscultation)Fluid accumulating in the lungs and productive cough.Disorders if Na+ and H2O Balance: Isotonic Fluid Volume Excess: Manifestations: Decrease in BUN and hematocritBoth are diluted.Disorders if Na+ and H2O Balance: Isotonic Fluid Volume Excess: TreatmentStop the increase in volume (ie. restrict intake), start decreasing the volume (ie. using diuretic), and treat the cause (ie. heart failure may be treated with digoxins).Disorders if Na+ and H2O Balance: Hyponatremia: Too little ECF NaShift in Na concentration due to inadequate Na intake or too much Na loss. Excessive Na loss may be indicative of renal deficiency (kidneys normally preserve Na via aldosterone). May also be linked to diuretic use, GI issues and NG suction; salt is lost in higher proportion to water, therefore you need to replace with fluid with electrolytes (plasma concentration is less than 135mmol/L).Disorders if Na+ and H2O Balance: Hyponatremia: Too much ECF waterShift in Na concentration due to osmotic pull (ie. hyperglycemia draws water into the vessel from the tissues) or too much water retention (plasma concentration is less than 135mmol/L).Disorders if Na+ and H2O Balance: Hyponatremia: Manifestations: Variable symptomsHighly dependent on the causes and speed of the onset of conditions (ie. gradual onset may result in few signs).Disorders if Na+ and H2O Balance: Hyponatremia: Manifestations: Fluid shifts to cells ie. Causing brain swelling and diarrheaFluid shifts from extracellular space into cells in the brain, this swelling causes headaches and may progress to changes in the levels of consciousness and coma. In the GI, shifts can cause diarrhea.Disorders if Na+ and H2O Balance: Hyponatremia: Manifestations: Neuromuscular effects (Inadequate sodium)Remember the role of Na in the transmission of nerve impulses in neurons and muscle fibers. Low Na may result in muscle cramping, fatigue, weakness, and tremors.Disorders if Na+ and H2O Balance: Hyponatremia: Manifestations: Decreased serum osmolalityDue to dilution of solutes, including BUN and hematocrit.Disorders if Na+ and H2O Balance: Hyponatremia: Treatment: Determine and treat the causeNot always possible; symptoms are usually treated instead. Treatment may include may include water restrictions and stopping medications.Disorders if Na+ and H2O Balance: Hyponatremia: Treatment: Decrease the fluid excess, possible Na replacement and monitor carefullySevere hyponatremia may merit Na replacement therapy; replacement is based on the found osmolality of the blood.Disorders if Na+ and H2O Balance: Hyponatremia: Inappropriate ADH secretion (SIADH)High levels of ADH due to syndrome due to issues in communication in the body.Disorders if Na+ and H2O Balance: Hypernatremia: Too much ECF NaUsually due to excessive intake; this is usually a rare cause as normally, an increase in blood osmolality will trigger the thirst response (serum Na level is over 145mmol/L).Disorders if Na+ and H2O Balance: Hypernatremia: Too little ECF waterUsually due to insufficient intake and abnormal water loss (water loss may be due to osmotic dieuresis at the level of the kidneys and particle loss into the filtrate. This may occur in hyperglycemia) (serum Na level is over 145mmol/L). This is a more common cause of hypernatremia (normal water loss).Disorders if Na+ and H2O Balance: Hypernatremia: Manifestations: Shrunken cells (ie. brain cells, skin and mucous membranes)Due to fluid movement from the cells to vasculature due to osmotic pressure.Disorders if Na+ and H2O Balance: Hypernatremia: Manifestations: Lab valuesIncreased in Na concentraion and increased in osmolality.Disorders if Na+ and H2O Balance: Hypernatremia: Manifestations: Volume depletion and ThirstImportant to remember, but not always reliable (thirst).Disorders if Na+ and H2O Balance: Hypernatremia: Treatment: Decrease salt, increase fluid, and correct slowlyCorrecting slowly is key!Potassium Imbalances: Basic K lab valuesThis is a major intracellular cation. Normal concentrations in cells is: 140 - 150mmol/L. ECF concentrations are usually 3.5 - 5mmol/L. K is lost mainly through renal function.Potassium Imbalances: Role of K in the bodyK is key in the regulation of membrane potentials; controls neurons and muscular cell excitability and contractility of the muscle cell.Potassium Imbalances: Hypokalemia: Causes: Too little K intakeMainly due to dietary issues or poor choice in IV therapy (lack of K in fluid).Potassium Imbalances: Hypokalemia: Causes: Too much K outputLost via kidneys due to the diuretic use (T and T like diuretics) or when aldosterone levels are too high.Potassium Imbalances: Hypokalemia: Causes: Shifts between intracellular and extracellular componentsFrom extra to intra cellular. May be due to insulin and drugs... which promote the movement of K into the cells.Potassium Imbalances: Hypokalemia: Manifestations: KidneysCannot concentrate urine while trying to preserve K, result in an increase in output and increase in plasma osmolality, resulting in an increase in thirst.Potassium Imbalances: Hypokalemia: Manifestations: GI tractAlteration of normal peristalsis, can result in anorexia, nausea and vomiting. Decrease in smooth muscle activity may result constipation or even paralytic ileus.Potassium Imbalances: Hypokalemia: Manifestations: Skeletal musclesAbnormal muscle contractions can cause fatigue, weakness, and muscle cramping.Potassium Imbalances: Hypokalemia: Manifestations: Cardiovascular systemMost serious side effect; issues in cardiac contractility and conductivity may cause postural hypotension and cardiac arrhythmias .Potassium Imbalances: Hypokalemia: Manifestations: Treatment: Prevention, replacement therapy (oral or IV), and correct slowlyBest to prevent the issue (ie. using K sparing diuretics, dietary changes). Replacement therapy takes place after K rich foods are not enough to restore balance.Potassium Imbalances: Hyperkalemia: Causes: Too rapid administration and too little outputHyperkalemia refers to K levels in excess of 5.0mmol/L and is a generally uncommon problem. Common in pt with renal failure or decreased ADH levels (results in elimination of Na and K as a result).Potassium Imbalances: Hyperkalemia: Causes: Shifts in intracellular and extracellualr compartmentsFrom the cells to the plasma. May occur in the event of tissue injury. In acidosis, the body tries to compensate for the high H+ concentration but shifting them into the cells, resulting in the movement of K from the cells to the plasma. In acidosis, renal function is also decreased, resulting in the further retention of K.Potassium Imbalances: Hyperkalemia: Manifestations: GI TractResults in nausea and vomiting with accompanying cramping and diarrhea.Potassium Imbalances: Hyperkalemia: Manifestations: NeuromuscularWeakness, dizziness, muscular cramps and abnormal parasthesia or sensations.Potassium Imbalances: Hyperkalemia: Manifestations: CardiovascularMost serious. Issues in conductivity resulting in slowed HR. Detected with an ECG. Severe enough excess may result in ventricular fibrillation, result in cardiac arrest.Potassium Imbalances: Hyperkalemia: Treatment: Restrict K intake and promote excretionPromote excretion via more aggressive treatment exchange Na for K in the intestinal tract. It is key to be aggressive, especially when dealing with Cardiac or muscular changes.Calcium, Phosphorus and Magnesium ImbalancesRegulated by Vitamin D, parathyroid hormone and calcitonin. Regulate levels of Ca, pH and Mg, ie calcitonin removes Ca from the extracellular plasma. Normal Ca++ 2.1 - 2.6 mmol/Litre. Neuromuscular and cardiovascular manifestations of imbalances.