Acid Base Balance and Fluid Balance disorder Dr ; Niazy B Hussam PhD candidate

Homeostasis A delicate balance of fluids, electrolytes, and acids and bases is required to maintain good health. This balance is called Homeostasis.

Body Fluids Intracellular fluid (ICF) Extracellular fluid (ECF) found within the cells of the body constitutes 2/3 of total body fluid in adults major cation is potassium Extracellular fluid (ECF) found outside the cells accounts of 1/3 of total body fluid major cation is sodium

Terms Osmosis Solutes Osmolality movement of water across cell membranes from less concentrated to more concentrated Solutes substances dissolved in a liquid Osmolality the concentration within a fluid

More Terms Diffusion Filtration Active Transport movement of molecules in liquids from an area of higher concentration to lower concentration Filtration fluid and solutes move together across a membrane from area of higher pressure to one of lower pressure Active Transport substance moves across cell membranes from less concentrated solution to more concentrated - requires a carrier

Routes of Fluid Loss Urine Insensible fluid loss Feces

Electrolytes Electrolytes are important for: Sodium Potassium Chloride Phosphate Magnesium Calcium Bicarbonate Electrolytes are important for: . Maintaining fluid balance . Contributing to acid-base regulation . Facilitating enzyme reactions . Transmitting neuromuscular reactions

Acid-Base Balance Acid-Base balance is: the regulation of HYDROGEN ions.

pH The acidity or alkalinity of a solution is measured as pH. The more acidic a solution, the lower the pH. The more alkaline a solution , the higher the pH. Water has a pH of 7 and is neutral. The pH of arterial blood is normally between 7.35 and 7.45

Hydrogen ions The more Hydrogen ions, the more acidic the solution and the LOWER the pH The lower Hydrogen concentration, the more alkaline the solution and the HIGHER the pH

Buffer Systems Regulate pH by binding or releasing Hydrogen Most important buffer system: Bicarbonate-Carbonic Acid Buffer System (Blood Buffer systems act instantaneously and thus constitute the body’s first line of defense against acid-base imbalance)

Respiratory Regulation Lungs help regulated acid-base balance by eliminating or retaining carbon dioxide pH may be regulated by altering the rate and depth of respirations changes in pH are rapid, occurring within minutes normal CO2 level 35 to 45 mm Hg

Renal Regulation Kidneys the long-term regulator of acid-base balance slower to respond may take hours or days to correct pH kidneys maintain balance by excreting or conserving bicarbonate and hydrogen ions normal bicarbonate level 22 to 26 mEq/L.

Factors Affecting Balance Age especially infants and the elderly Gender and Body Size Environmental Temperature Lifestyle Stress Amount of fat

Henderson-Hasselbach Equation Demonstrates interrelationship between Carbonic acid Bicarbonate pH pH = pK + log [HCO3-] /[H2CO3]

Acid-Base Imbalances Respiratory Acidosis Respiratory Alkalosis Metabolic Acidosis Metabolic Alkalosis

Respiratory Acidosis Mechanism Etiology Hypoventilation or Excess CO2 Production Etiology COPD Neuromuscular Disease Respiratory Center Depression Late ARDS Inadequate mechanical ventilation Sepsis or Burns Excess carbohydrate intake

Respiratory Acidosis (cont) Symptoms Dyspnea, Disorientation or coma Dysrhythmias pH < 7.35, PaCO2 > 45mm Hg Hyperkalemia or Hypoxemia Treatment Treat underlying cause Support ventilation Correct electrolyte imbalance IV Sodium Bicarb

Respiratory Alkalosis Risk Factors and etiology Hyperventilation due to extreme anxiety, stress, or pain elevated body temperature overventilation with ventilator hypoxia salicylate overdose hypoxemia (emphysema or pneumonia) CNS trauma or tumor

Respiratory Alkalosis (cont) Symptoms Tachypnea or Hyperpnea Complaints of SOB, chest pain Light-headedness, syncope, coma, seizures Numbness and tingling of extremities Difficult concentrating, tremors, blurred vision Weakness, paresthesias, tetany Lab findings pH above 7.45 CO2 less than 35

Respiratory Alkalosis (cont) Treatment Monitor VS and ABGs Treat underlying disease Assist client to breathe more slowly Help client breathe in a paper bag or apply re breather mask Sedation

Metabolic Acidosis Risk Factors/Etiology Conditions that increase acids in the blood Renal Failure DKA Starvation Lactic acidosis Prolonged diarrhea Toxins (antifreeze or aspirin) Carbonic anhydrase inhibitors - Diamox

Metabolic Acidosis (cont) Symptoms Kussmaul’s respiration Lethargy, confusion, headache, weakness Nausea and Vomiting Lab: pH below 7.35 Bicarb less than 22 Treatment treat underlying cause monitor, I&O, VS, LOC Sodium Bicarb? ABG

Metabolic Alkalosis Risk Factors/Etiology Acid loss due to vomiting gastric suction Loss of potassium due to steroids diuresis Antacids (overuse of)

Metabolic Alkalosis (cont) Symptoms Hypoventilation (compensatory) Dysrhythmias, dizziness Paresthesia, numbness, tingling of extremities Hypertonic muscles, tetany Lab: pH above 7.45, Bicarb above 26 CO2 normal or increased w/comp Hypokalmia, Hypocalcemia Treatment I&O, VS, LOC give potassium treat underlying cause

Interpreting ABGs 1. Look at the pH is the primary problem acidosis (low) or alkalosis (high) 2. Check the CO2 (respiratory indicator) is it less than 35 (alkalosis) or more than 45 (acidosis) 3. Check the HCO3 (metabolic indicator) is it less than 22 (acidosis) or more than 26 (alkalosis) 4. Which is primary disorder (Resp. or Metabolic)? If the pH is low (acidosis), then look to see if CO2 or HCO3 is acidosis (which ever is acidosis will be primary). If the pH is high (alkalosis), then look to see if CO2 or HCO3 is alkalosis (which ever is alkalosis is the primary). The one that matches the pH (acidosis or alkalosis), is the primary disorder.

Compensation The Respiratory system and Renal systems compensate for each other attempt to return the pH to normal ABG’s show that compensation is present when the pH returns to normal or near normal If the nonprimary system is in the normal range (CO2 35 to 45) (HCO3 22-26), then that system is not compensating for the primary. For example: In respiratory acidosis (pH<7.35, CO2>45), if the HCO3 is >26, then the kidneys are compensating by retaining bicarbonate. If HCO3 is normal, then not compensating.