Active transport K + K + K + K + K + K + K + K + K + K + K + K + K + K + K + K + K + ATP ATP ATP ATP Na + Na + Na + Na + Na + Na + Na + Na + Na + Na + Na + Na + Na + Na + Na + Na + Na + Na + Na + Na + Figure 4. INTRACELLULAR FLUID EXTRACELLULAR FLUID
BLOOD VESSEL NORMAL CELL ISOTONIC
BLOOD VESSEL SHRUNKEN CELL HYPERTONIC
HYPOTONIC BLOOD VESSEL SWOLLEN CELL
Chemically, electrolytes are substances that become ions in solution & acquire the capacity to conduct electricity.
Essential for normal function of the cells & our organs.
Sodium, Potassium, chloride, & Bicarbonate
135 to 145 mEq/L (135-145 mmol/L)
Major positive ion in fluid outside the cells.
Regulates the total amount of water in the body & the transmission of into & out of cells.
3.5 to 5.0 mEq/L (3.5 to 5.0 mmol/L)
Major positive ion found inside the cells.
Regulation of the heartbeat & function of the muscles.
98 to 108 mmol/L
Major anion (negatively charged ion) found outside the cells & in the blood.
Helping the body maintain a normal balance of fluids
22 to 30 mmol/L
Acts a buffer to maintain the normal level of pH in the blood & other fluids in the body.
Measured to monitor the acidity of the blood & body fluids.
Occurs when the fluid is “trapped” in the interstitial spaces.
Fluids shifts from the vascular space into an area where it is not readily accessible as extracellular fluid.
This fluid is remains in the body but is essentially unavailable for use, causing an isotonic fluid volume deficit.
Pt. may not manifest fluid loss or weight loss.
Decreased Oncotic Pressure
Loss of albumin or protein leads to decreased oncotic pressure, causing fluid to “leak” from the intravascular space to the interstitial space
Due to the loss in circulating fluid volume, cardiac output decreases
Causes of Fluid Shifts
Albumin losses can occur in liver failure, liver dysfunction, and malnutrition
Albumin losses can lead to fluid shifting into the peritoneum, causing ascites
Destruction of endothelial cells, such as in bowel surgery, can cause fluid to move and be trapped in the interstitial spaces
Fluid trapped in the lungs can lead to pulmonary edema
Inside the Cells
Interstitial fluid trapping can cause compression of the microvasculature, resulting in hypoperfusion and ischemia
Inflammatory “mediators” are released into the bloodstream, which can lead to systemic inflammatory response syndrome (SIRS)
Multiple organ dysfunction syndrome (MODS) occurs, leading to organ failure and death
What Happens When Fluids Shift?
With decreased circulating volume, baroreceptors in the aorta are activated
Sympathetic nervous system releases epinephrine and norepinephrine, causing vasoconstriction and an increased heart rate
Kidneys launch the renin-angiotensin-aldosterone system in response to a lower glomerular filtration rate
All this happens with the goal of increasing circulating volume, blood pressure, and cardiac output
Fluid Shift in the Bowel
Causes abdominal distention
Measure bladder pressure and abdominal girth at least every 4 to 8 hours while signs are abnormal.
Monitoring the Patient
Fluid shift will either resolve over the next several hours (up to 48 hours) or the patient will continue to develop bowel edema and, eventually, ischemia