Fluid , Electrolytes, & Acid Base Balance

135-145 mEq/L

3.5-5.3 mEq/L

7.35-7.45

35-45

22-26

1. Increased Blood Hydrostatic Pressure 2. Decreased Plasma Oncotic Pressure 3. Increased Capillary Permeability 4. Obstruction of Lymphatic Vessels

Increased plasma volume leads to an increased hydrostatic pressure which results in increased filtration pressure "pushing" more water out of the capillaries at the arteriolar end resulting in edema. This is characterized by ECF excess.

Decreased plasma oncoic pressure results in a decreased "pull" pressure at the venous end of the capillaries so less water is "pulled" back in and instead remains in the interstitial space resulting in edema

Plasma proteins "leak" into the interstitial spaces usually due to capillary damage or a localized inflammatory or allergic reaction, which results in an interstitial oncotic pressure in the area which "pulls" water from the plasma into the interstitial space causing edema. The plasma volume goes down while the interstitial volume goes up.

Blockage or removal of lymphatic vessels prevents lymphatic drainage and causes edema. Edema is distal to the area of interruption of lymphatic drainage.

Excess fluid intake- increase in free water intake, excessive IV fluids, or excessive Na+ intake Decreased urine output- renal failure, decreased cardiac output, liver disease, inflammation, steroid therapy, low protein diet

Age Acute illness Chronic illness Diet and lifestyle Medications Environmental factors (FVD)

Surgery initiates the stress response which increases the release of ADH and aldosterone which promotes fluid and Na+ retention Patient receiving IV fluids for medical problems are also at risk

Cardiovascular disease reduces pumping strength of the heart resulting in decreased flow to the kidneys, leading to Na+ and water retention. Renal disease can lead to abnormal retention of water, Na+, and other electrolytes. SIADH produces excess ADH and can be caused by stress, surgery, lung tumors, or brain tumors Psychogenic polydipsia is compulsive water intake caused by certain psychiatric disorders

Plasma Excess- rapid bounding pulse, slow venous emptying, neck vein distention, and capillary refill less than 3 seconds Interstitial Excess- sudden weight gain, peripheral edema, pulmonary edema, drowsiness, blurred vision, headache