FLUID AND ELECTROLYTES

intracellular 

fluid that is inside the cells 

intracellular

composed of 2/3rd or 70% of fluids

40% of total body weight

intracellular

primarily located inside the skeletal muscles

extracellular

composed of 1/3rd or 30% of fluids

20% of total body weight

extracellular

responsible for the transport of the electrolytes & other substances such as enzymes and hormones

interstitial, intravascular, transcellular

compartments of extracellular fluids 

interstitial 

fluids that surround the cell

11-12L 

intravascular 

inside the blood vessel, fluid into the circulation

6L 

transcellular 

smallest compartment of extracellular

1L 

third space fluid shift

the body fluid normally move between the 2 major compartment (ECF & ICF), but any loss of fluid from the body can disrupt the equilibrium

third space fluid shift

fluid goes to other spaces that do not contribute t the equilibrium state

decreased urine output, increased heart rate, decreased blood pressure, decreased central venous pressure, edema

manifestations of third space fluid shift

fluid exists the blood vessels, therefore the kidney receives less blood perfusion

cause of decreased urine output in third space fluid shift 

there is less blood that enters our heart, our heart compensates by pumping more blood

why is there increased heart rate in third space fluid shift

there is decreased blood volume, that is why the systemic ventricular resistance is low

why is there decreased blood pressure in third space fluid shift

fluid exists intravascular space, so it enters the interstitial spacesthat cuases edema 

why is there edema in third space fluid shift

intestinal obstruction, pancreatitis, crushing injuries, bleeding, peritonitis, venous obstruction 

causes of third space fluid shift

electrolytes

these are the active chemicals that are found in the body fluids

Na, K, Ca, Mg, H+

what are the cations

cation

these help in contractions and the concentration of the electrolytes

Cl, HCO3, PO4, SO4, protein ions 

what are the anions 

osmosis

movement of solvent from an area of lower to higher concentration of solute that is due tot he higher concentration of sodium in the ECF that influence the movement of water 

diffusion 

movement of solute from an area of higher concentration to a lower concentration of solute 

hydrostatic pressure

pressure exerted by the fluids on the walls of the blood vessels

filtration 

movement of H2O from higher to lower hydrostatic pressure 

osmolality 

Number of dissolved particles contained in a unit of fluid. Or the amount of solutes such as sodium or glucose in an amount of fluid

serum osmolality 

it can be determined by the concentration of sodium, BUN, glucose and other solutes

275-290 mOsm/kg

normal serum osmolality

urine osmolality

can be determined by the concentration of urea, creatinine and uric acid

200-800 mOsm/kg

normal urine osmolality

tonicity

Ability of all solutes to cause an osmotic driving force that promotes water movement between compartments

normal state of cellular hydration and cell size

what will the control of tonicity determine?

lungs 

It normally eliminates fluid loss through water vapor as insensible loss during respiration

skin

fluids and electrolytes loss in this organ is considered insensible lossess, because it is difficult to measure

0-1000mL per hour

normal value of skin fluid loss

300mL per day

normal value of lung fluid loss

100-200mL per day

normal value of gi tract fluid loss

urine specific gravity

measures kidney’s ability to conserve or excrete water

1.010-1.025

normal urine specific gravity

BUN

An end product of protein metabolism by the liver

creatinine 

Is the end product of muscle metabolism.

Is a better indicator of renal function than BUN because it doesn’t vary with protein intake and metabolic state.

0.7-1.4 mg/dL

normal value of creatinine

hematocrit

It measures the volume of RBC in the whole blood

35-47%

normal hematocrit for females

42-52%

normal hematocrit for males 

Dehydration, polycythemia, over hydration, anemia, bleeding and destruction of RBC

factors of high HCT

kidneys

heart and blood vessels 

lungs

pituitary glands 

adrenal glands 

parathyroid glands 

organs involved in homeostasis

kidneys

Filters 180 liters of plasma and excrete only 1-2 liters of urine (due to reabsorption)

kidneys 

act independently from other organs in controlling fluid reabsorption and excretion. They also response to blood born messengers, wherein they act due to stimulations of mechanism such as aldosterone and anti-diuretic

heart and blood vessels

pumps oxygenated blood to the kidneys for renal perfusion

posterior pituitary glands 

it stores ADH, also known as vasopressin. That is manufactured by the hypothalamus

ADH 

maintain the osmotic pressure of the cells by controlling the retention or excretion of water

adrenal glands

Secretes aldosterone, specifically zona glomerulosa

parathyroid gland

secretes parathyroid hormones which regulates calcium and balance of phosphate

parathyroid gland 

It also influences calcium absorption from the intestines from dietary intake and renal tubules. Particularly from your proximal convoluted tubules, loop of Henle, and distal convoluted tubules

baroreceptors 

Located in the left atrium and the carotid and aortic arches, which functions to maintain stable BP levels and homeostasis 

renin angiotensin aldosterone system (RAAS)

Responds to low circulating blood volume and low BP

renin

secreted by the juxtaglomerular cells of the kidneys.

natriuretic peptides

Hormones that affect fluid volume and cardiovascular function through the excretion of sodium such as natriuresis, direct vasodilation and opposition of the RAAS

natriuretic peptides 

It also helps for fluid balance through the opposition of the RAAS by inhibiting the production of renin and aldosterone

1. atrial natriuretic peptides (ANP)

2. brain natriuretic peptide (BNP) 

3. c-type natriuretic peptide (CNP) 

4. d-type natriuretic peptide (DNP) 

what are the 4 natriuretic peptides released by the heart

atrial natriuretic peptides (ANP)

Produced by atrial myocardium and is distributed in the cardiac atria and ventricles

Is a peptide by the atrial muscles in response to several factors that includes increase in atrial BP, angiotensin 2 stimulation, endothelin release, SNS discharge

brain natriuretic peptide (BNP) 

Is produce by the ventricular myocardium. There is tissue distribution in the brain and cardiac ventricle

c-type natriuretic peptide (CNP)

Which has tissue distribution in the brain, ovary, uterus, testis and epididymis

d-type natriuretic peptide (DNP)

this is the newest peptide, which has structural with other peptide

osmoreceptors 

- Located on the surface of the hypothalamus.

- It senses changes in sodium concentration. That transmits signals for ADH to be released 

hypovolemia & hypervolemia

fluid volume imbalances

hypovolemia

- Occurs when there is a loss of fluids than the fluid intake.

- Prolonged period of inadequate fluid intake.

abnormal fluid losses, GI suctioning, sweating, nausea, diabetes insipidus, adrenal insufficiency, osmotic diuresis

causes

• Thirst • Weight loss • Muscle weakness • Oliguria • Concentrated urine • Cool clammy skin, pale skin (due to decreased in BP) • Confusion, lethargic, shock (late sign)

manifestations of hypovolemia 

increase OFI

mild hypovolemia mngt.

parenteral fluid resuscitation (PLR or PNSS)

severe hypovolemia mngt.

• Congested hearth failure - inability to circulate fluid • Renal failure • Liver cirrhosis - results in liver failure • Excessive intake of salt

causes of hypervolemia

• Distended neck veins (JVD) - due to fluid overload • Edema - due to third spacing • Crackles/SOB/Wheezing • Elevated BP • Increased urine output • Weight gain

manifestations of hypervolemia 

• Correct the cause • Diuretics (furosemide/thiazide) - is prescribed depends on the amount of fluid. • Hemodialysis • I/O and weight and VS monitoring • Assessment of breath sounds and degree of edema • Sodium and fluid restriction

management for hypervolemia