Nursing 105 Assessment & management of hydration, fluids & electroytes

Purpose of fluid in the body

• Transport medium

• solvent

• thermoregulation

• digestion and elimination

• lubrication

• cellular metabolism/function

• fluid dynamics

Intracellular

28L

Extracellular

14L

• Intravascular

• Interstitial

• Lymph

• Transcellular

How does fluid get in and out?

• Eating + drinking

• metabolism

• perspiring

• breathing

• urine output

• GI output

Most electrolytes enter the body in ___________, and most are excreted in ________

dietary intake, urine

Na+ & Cl-

aren’t stored so must be consumed regularly

Ka+ & Ca+

are stored in cells and bones

Cations & anions

dissolve in water

Na+ regulates…

Water balance, transmission of nerve impulses, Na-K pump

N for neurons

Cl- regulates…

With sodium maintains osmotic pressure

K+ regulates…

Electrical cardiac nerve conduction, cell metabolism-gluconeogenesis

K for kardiac

Ca+ regulates…

Nerve impulses, blood clotting, muscle contraction, needs vit D to be absorbed

PO4- regulates…

Helps form bones, cellular and nutrient metabolism, muscle, nerve and RBC function, CA levels and acid-base balance

Mg2+ regulates…

Relaxing muscle contractions, transmitting nerve impulses, regulates cardiac function, blood clotting, protein & DNA synthesis

HCO3 regulates…

essential part of carbonic acid-bicarbonate buffering system, regulated by kidneys

Homeostasis of fluid and electrolyte dependant on functioning of…

• kidneys

• heart

• lungs

• nervous system

• adrenal pituitary and parathyroid glands

Renin

Produced in kidneys

Converts Angiotensinogen to angiotensinogen I

Angiotensin converting enzyme (ACE)

Produced in lungs

Converts angiotensin I to angiotensin II

Angiotensin II leads to…

• Aldosterone

• ADH

• Systemic vasoconstriction

Aldosterone

Sodium/water retention in proximal convoluted tubules

ADH (pituitary)

Thirst/water intake (hypothalamus)

Reduced baroreflex to increase pressure

Most at risk of imbalances

Due to uncompensated gains or losses

• Experiencing high intake

• Experiencing high output

• Unable to compensate for intake/output due to acute or chronic medical conditions

Hypovolemia

low circulating volume

Hypervolemia

Excess circulating volume

Comorbidities

• GI

• renal

• neurological

• cardiac diagnosis

Increased risk of of fluid + electrolyte imbalance

Age

• Elderly - thirst response blunted and nephrons less able to conserve water

• Increased likelihood of heart diseases, impaired RF, multiple meds

• Younger people have more body fluid, more prone to dehydration (more demand for water)

Gender/body size

• Fat cells have no H2O

• Women have more fat = less body water

• More obese, more fat = less water

Hospitalised

• IV or PO therapies

• NBM/GI disturbance

Diet

• Anorexia, bulimia

• malnourishment-low albumin

• oedema acidosis

Lifestyle

• Smoking, etc.

Exercise

• Weight-bearing-CA balance

• electrolyte loss

Inadequate intake

• Nausea/anorexia

• difficulty swallowing

• lack of water access

• NBM/intubation

Uncompensated loss

• Diarrhoea

• vomiting

• polyuria

• Haemorrhage

• Burns

Symptoms of fluid volume deficit

• dry oral cavity/furrowed tongue

• thirst

• cool pale skin, delayed capillary refill

• weak, rapid pulse

• decreased blood pressure

• orthostatic hypertension

Orthostatic hypotension occured when a person’s _________ falls when suddenly standing up from a lying/sitting position

Defined as a fall in _________ blood pressure of at least 20mmHg or _________ blood pressure of at least 10mmHg when a person assumes a ________ position

Occurs by delayed __________ of ___________ blood vessels, which is normally required to maintain an adequate ________ when changing position to standing

As a result, blood pools in the ______ of the ________ for a longer period and less is returned to the ________ thereby leading to reduced ___________

Mild orthostatic hypotension common however prevalent among the ________ and those with known _________

Severe drops in BP can lead to _________ with possibility of injury

• blood pressure

• systolic, diastolic, standing

• constriction, lower body, blood pressure

• blood vessels, legs, heart, cardiac output

• elderly, low BP

• fainting

FVD interventions

• Clinical assessment

• Reduce losses

• Increases intake

Reduce losses

• Treat GI disturbances

• Reduce diuretics

• Stop bleeding

Increase intake

• Oral rehydration

• IV rehydration

Replacement fluids usually contain some electrolytes - why?

With fluid shift comes electrolyte shift

Crystalloid

Solute that can pass through a semipermeable membrane

Isotonic crystalloids

• 0.9% NACL

• Ringers

• Plasmalyte

Same osmolality as body fluids

Hypertonic crystalloids

• 5% dextrose

Higher osmolality

Hypotonic crystalloids

• H20

• 0.45% NACL Ringers

Lower osmolality

Colloids

• Albumin, FPP

• Plasma protein fraction

Colloid substitutes

• Dextran

• Hetastarch

Blood transfusions

• Packed RBCs

• Whole blood

Causes of fluid volume excess

• Uncompensated intake

• Inadequate output

Uncompensated intake

• Excessive IVF administration - includes blood transfusion

• Excessive water consumption (polydipsia)

Inadequate output

• Heart failure

• Endocrine disturbances e.g. hyperaldosteronism

• Liver failure

• Renal impairment

• Anuria (no urine output)/oliguria (scant urine output)

Symptoms of FVE

• Neurological

  • Changes in LOC (level of consciousness)

  • confusion

  • headache

  • seizures

• Respiratory

  • Pulmonary congestion

• Cardiovascular

  • bounding pulse

  • increase BP and JVD

  • Presence of S3

  • Tachycardia

• GI

  • Anorexia

  • Nausea

• Oedema

  • Dependant pitting edema

Third space fluid

Shift of body fluids into potential spaces such as pleural, peritoneal, pericardial or joint cavities; the bowel; or the interstitial space

• Fluid moves out of intravascular spaces (plasma) to any of these spaces

• deficit in ECF volume occurs - fluid has not been lost but is trapped in another body space and unavailable for use

Fluid shifts may be related to…

• a decrease in colloid osmotic pressure

• an increase in capillary membrane permeability

• a severe burn, a bowel obstruction or hypoalbuminaemia

FVE interventions

• Clinical assessment

• Restrict fluid/sodium intake

• close fluid balance monitoring e.g. weight

• ± diuretics

• dialysis

Nursing process for fluid balance

• identify patients at risk of imbalances

• determine that a specific imbalance is present and its severity, aetiology and characteristics

• determine effectiveness of plan of care

Health history

• risk factors for imbalances

• comorbidities/chronic illnesses

• abnormal fluid loss: burns, trauma, infection D&V, wounds

• therapy that disrupts F&Es

Physical assessment

• fluid balance in and out

• daily weighs

• Skin and mucous membranes

• vital signs/haemodynamic monitoring

• signs of FVE and FVD

• Signs of electrolyte imbalance

• Quality, colour and consistency of fluids coming out

Laboratory studies

• Electrolytes

• FBC

• haemotocrit

• albumin

• osmolality

• Urine pH and specific gravity

• ABGs

• 24 urine (GFR)

Restoring electrolyte balance

• treatment depends on aetiology (causal factors), severity, clinical signs, symptoms, rate of onset

• can be difficult to treat (hyponatraemia and hyperkalaemia)

• gradual approach preferred, unless condition life threatening

Reducing losses

Restoring electrolyte balance

• restore normothermia

• treat nausea and diarrhoea

• return GI aspirates

• reduce diuretics

Replacement

• oral rehydration with electrolytes

• oral electrolyte supplements

• IV fluids with electrolytes

Reducing toxicity

Too much water

• time

• hydration/dilution

• restrict intake

• diuretics

• glucose and insulin

• calcium gluconate

• dialysis

Hypokalemia

• Major cation of ICF

• body more sensitive to small changes in serum K+ than other electrolytes

• K for kardiac!

Hyperkalemia

• most common in patients with renal impairment or failure

• life threatening

• may require urgent intervention

Hyponatraemia FVD

Salt and water supplementation

Hyponatraemia FV balanced

fluid restriction

Hyponatraemia FVE

fluid restriction, ± diuretics, sodium supplementation

Hypernatraemia symptoms

• dry mouth

• low grade fever/flushinh

• oedema, increased BP