Dehydration/Thirst/Fluid loss and excess

• What are the signs and symptoms of dehydration?

  confusion, dry skin, lips, general weakness, tachycardia, low urine output Following a GI infection which caused vomiting and diarrhea.
• what are the signs and symptoms of Hypovolaemia?

  decreased blood pressure, increased heart rate, increased respiratory rate.

  -pale, cool and clammy skin

  -decreased urine output

  -anxiety, confusion, agitation postoperatively
• What is thirst?

  how does the body respond?

  what age is this mechanism less effective?

  response to dehydration =decreased blood volume thus leading to an increase in concentration of sodium(Na).

  -Thirst is the body’s mechanism for maintaining fluid balance

  -Sensitized osmoreceptors respond to dry mouth and increased blood osmolarity and stimulate the thirst center( hypothalamus)

  -pituitary will then release ADH which increases water absorption in the kidneys

  -the thirst mechanism is less effective in the older adult
• Explain the thirst mechanism flow chart?

  Flow chart

  
• Describe the flow of thirst/ regulation of fluid balance?

  Decreased BP causes increase in angiotensin II,

  
• Antidiuretic hormone (ADH)? Explain Stimulus, receptor and control center steps 1-3

  1. Stimulus: Angiotensin II, low blood volume and increased blood osmolarity
  2. Receptor: the hypothalamus responds to stimuli
  3. Control center: the hypothalamus stimulates the posterior pituitary to release ADH into the blood
• ADH explain effectors and net effect step 4 and 5?


  4)Effectors: ADH binds to effectors to cause, Hypothalamus-activation of thirst center to increase fluid intake which increases blood volume and BP, Kidneys- increased water reabsorption which decreases water lost in kidneys to maintain blood volume and decreases blood osmolarity, Blood vessels(get high dose of ADH)- vasoconstriction increases peripheral resistance and blood pressure

  5)Net Effect: BP and blood volume increase with increased fluid intake, blood osmolarity decreases
• Fluid volume deficit, signs and symptoms and interventions?

  Signs and symptoms

  •Low BP, high HR

  •Dry mouth, thirst

  •Rapid weight loss

  •Low urine output

  •Confusion, lethargy

  •Low grade fever

  What can you do?

  •Fluids (oral if alert)

  •IV – normal saline (no potassium until urine output is increased)

  •Daily weight, strict vital signs

  •May need antidiarrheals, antiemetics, abx, antipyretics=prevent more fluid loss
• Fluid volume excess, what is it and main symptoms?

  -Hypervolemia: Too much IV fluid, kidney failure, corticosteroids

  -Isotonic excess with hypervolemia=when too much fluid in ECF causing circulatory overload

  -Hypotonic hypervolemia= water intoxication causing electrolyte imbalance due to dilution of solutes

  -Water intoxication:CHF, ADH problems, IV fluids, psych problems, wound irrigation

  -Too much sodium intake: Too much salt, 3% saline IV, too much NaHCO3
• Explain the flow chart of fluid shifts in heart failure?

  begins with heart issues

  
• Explain the importance of hydration for our body?

  -Moistens tissues such as the mouth, eyes and nose

  -Protects body organs and tissues

  -Helps prevent constipation

  -Helps dissolve minerals and other nutrients to make them accessible to the body

  -Regulates body temperature

  -Lubricates joints

  -lessens the burden on the kidneys and liver by flushing out waste products

  -Carries nutrients and oxygen to cells
• why does dehydration occur?

  •Occurs when water loss exceeds water intake over a period of time and the body is in a negative balance

  •Caused by decrease of ECF volume – loss of NA+ containing fluid from the body

  •Causes include: vomiting, diarrhoea, haemorrhage, burns, profuse sweating,

  water deprivation and diuretic abuse
• Hydration assessment?

  -Assessing skin turbot: arm, abdoen

  
• what is a normal daily urinary output?

  0.5-1.5mls/kg/hour

  so a patient should be urinating at least once every 6 hours

  absoulte minimum of 30cc/hour
• The most reliable index of volume status when caring for a patient with a fluid imbalance is:

  A skin turgor

  B presence of oedema

  C hourly urine output

  D daily weight patterns

  D, main one but also do others
• The nurse monitors a patient with prolonged vomiting for fluid volume deficit, recognising that fluid shifts that occur as a result of vomiting include:

  A Fluid movement from the cells into the interstitial space and the blood vessels

  B Fluid movement from the vascular system, causing cellular

  swelling and rupture

  C An overload of extracellular fluid with a significant increase in intracellular fluid volume

  D Excretion of large amounts of interstitial fluid with depletion of extracellular fluids and fluid movement out of the cells

  A
• Why are fluids and electrolytes important?

  They are essential for the body to function and to maintain homeostasis, they aren’t static and are always moving between the intracellular and extra cellular compartments this movement ensures that cells have a constant supply of electrolytes
• explain how water is essential for the body as it acts as?

  
  

  -acts as a lubricant

  -transports nutrients (e.g. glucose), gases (e.g. oxygen), hormones and enzymes to the cells. it also trnapsorts waste products of metabolism (e.g. carbon dioxide, urea and uric acid) from the cells for excretion

  -helps in the regulation of body temperature

  -provides an optimum medium for the cells to function

  -provides a medium for chemical reactions

  -break down food particles in the digestive system.
• How is water obtained and excreted?

  Most water is obtained through drinking water, food and some cellular metabolism. The kidneys are key in fluid balance as water is excreted in urine produced by the kidneys, some water is also lost through respiration, the skin and excrement
• Explain the three ways in which dehydration stimulates the thirst reflex?

  1)the blood osmotic pressure increases, resulting in the stimulation of the osmoreceptors of the hypothalamus.

  2) circulating blood volume decreases, which initiates the renin-angiotensin-aldosterone system (RAAS), resulting in the stimulation of the thirst centre in the hypothalamus.

  3) the mucosal lining of the mouth becomes dry and the production of saliva decreases, which stimulates the thirst centre in the hypothalamus.
• What are the two key hormones that regulate fluid and electrolyte balance?

  Antidiuretic hormone(ADH) regulates fluid balance in the body and Aldosterone Regulates both fluid and electrolyte balance.
• how is ADH produced?

  ADH is produced in the hypothalamus by neurons called osmoreceptors and is stored by the posterior pituitary gland. osmoreceptors are sensitive to plasma osmolality and a decrease in blood volume. the target organs for ADH are the kidneys. ADH acts on the distal convoluted tubule and the collecting ducts, making them more permeable to water, thus increasing reabsoprtion of water.
• what produces aldosterone?

  aldosterone is a steroid hormone produced by the cortex of the adrenal glands, which are situated at the top of each kidneys. the adrenal gland is divided into the cortex and the medulla. aldosterone regulates electrolyte and fluid balance by retaining sodium and water.
• What happens if fluid balance isn’t maintained?

  Health problems can occur if fluid balance isn’t marinated which occurs when fluid entering the body equals fluid exiting the body.
• what is fluid overloading?

  health problems can occur if the patient has too much fluid like kidney disease and heart disease, when this occurs the patient will struggle to get rid of the excess water and can cause an oedema.
• why is it important to monitor fluid balance in patients with fluid issues?

  it’s important to use a fluid balance chart to monitor the patients input and output each time they the patient takes fluids and or excretes fluids.
• what are the consequences of poor hydration?

  -pressure sores as dehydration reduces the padding over bony prominences.

  -chronic constipation

  -poor quality of life and poor health care outcomes

  -can cause low sodium levels

  -fall risk as they can be disoriented, dizzy and headaches thus higher risk of fainting
• benefits of proper fluid intake?

  -important in the prevention of UTIs as it keeps their urinary tract healthy

  -promotes renal function

  -dilutes bile and stimulates gallbladder emptying this reducing risk of gallstones

  -reduces risk of coronary heart disease

  -lowers risk of diabetic keto acidosis, help maintain blood sugar levels
• Explain ADH simply following the chart?

  ADH

  when you have low blood volume it increases angiotensin II, it then increases blood osmolairty and stimulates hypothalamus which causes posterior pituitary to release ADH to circulate blood and go to all the effector sites

  
• Explain the flow chart of ANP? What does it do ?


  ANP, when too much fluid ANP and the B type natriuretic peptide(BNP) which is released from the atrial muscle in response to stretch in fluid overload, so we know when the atrial muscle stretches too far it has prompted the release ANP

  
• What are the four main hormones/ systems that keep fluid balance in check?

  ADH=regulate fluid and electrolytes,initiated by osmoreceptors in the hypothalamus and stored in pituitary, targets kidneys distal tumbles and collecting ducts making them more permeable to water= increase water absoprtion=decrease water secretion

  Aldosterone=regulate fluid and electrolytes, produced by adrenal cortex on top of kidneys and retains sodium and water to restore fluid balance

  RAAS=

  Atrial natriuretic peptide(ANP)=released from atrial muscle in response to stretch in fluid overload when too much fluid
• What are causes of fluid volume deficit? No water

  -No water( hypertonic), dehydration from loss of water alone without corresponding loss of sodium, signs sweating, hyperventilation, DKA, fever, diarrhea, renal failure, diabetes insipidus

  -no water will cause solutes to become more concentrated
• Fluid volume deficit No salt?

  No salt aka hypotonic occurs when electrolytes are lost, from water intoxication, chronic illness, malnutrition and renal failure
• Fluid volume deficit from both losing water and electrolytes?


  Typical forms are dehydration, hemorrhage and D&V
• Fluid volume excess signs and symptoms, interventions?

  Signs and symptoms:

  • rapid weight gain
  • oedema
  • high BP, bounding pulse
  • increased urine output
  • JVD(jugular vein distention)=evident of fluid volume excess
  • crackles, dyspnea=lung sounds
  • decreased LOC(level of consciousness)

  interventions:

  -Diuretics =remove excess water

  -Fluid restriction( no IV fluids)

  -Sodium restriction=as Na+ will attract water

  -Daily weights, Strict intake and output
• How does ADH effect the hypothalamus?

  Hypothalamus-activation of thirst center to increase fluid intake which increases blood volume and BP
• how does ADH effect the kidneys

  Kidneys- increased water reabsorption which decreases water lost in kidneys to maintain blood volume and decreases blood osmolarity
• how does ADH effect blood vessels?

  Blood vessels(get high dose of ADH)- vasoconstriction increases peripheral resistance and blood pressure
• What two mechanisms that try to maintain homeostasis during dehydration? Explain what the osmoreceptors do in regard to fluid restoration?

  Baroreceptors are stimulated by changes in fluid volume and osmoreceptors are stimulated by levels of solutes in the blood

  -with further blood loss osmoreceptors of the Aorta and carotid sinus stimulate release of anti diuretic hormone from the primary gland, when ADH is release it attempts to promote the restoration of plasma volume and BP, acts on collecting ducts of kidneys to increase water absoprtion

  -Solutes: electrolytes like Na+ and K+
• What happens once fluid deficit is treated?

  Urine output will increase, Heart rate will decrease, BP increase=Homeostasis will occur/be regained