ACID BASE Flashcards
Function of Acid-Base
Homeostasis
Body fluids
Kidneys
Lungs
How do we measure acid-base?
PH
- Normal is 7.35-7.45
Acid- Base Buffer
Carbon Dioxide mixes with water to form carbonic acid
Bicarbonate and hydrogen ions mix to form carbonic acid
Both processes require carbonic anhydrase to occur
CO2 is controlled by what
Respiratory
HCO3- is controlled by what
Metabolic
Breathing controls what acid
CO2
RR less than 12 promotes?
increased CO2
RR greater than 20 promotes?
decreased CO2
How fast does the respiratory system respond to change?
Immediately but effect is weak
The kidneys primarily control acid-base balance through the retention or excretion of two substances
Hydrogen ions
Bicarbonate ions
Renal System responds how?
- it takes hours to days
- very effective though
How do we figure out what acid-base status is in real world?
Arterial Blood Gas (ABG)
Sample of blood taken from an artery
Most common radial or femoral
Run through a machine for various values
Low pH
High Co2
Low Hco3
Acidic Resp is opposite and metabolic is equal
High pH
low Co2
High HCO3
Alkaline
Compensation
If ph is below 7.35 body will compensate to 7.31-7.35
If pH is higher than 7.45 body will compensate to 7.41-7.45
- 7.4 is midpoint
Uncompensated
When one resp or metabolic is abnomal and pH is abnormal
Partially Compensated
When all 3 are abnormal
Compensated
when both bicarb and resp are abnormal but pH is normal
Metabolic Acidosis Causes
Excess carbonic acid production or bicarbonate deficit with multiple causes:
- DKA and Lactic Acid accumulation from not enough oxygen in tissues
-Severe Diarrhea: Dehydration, can lead to shock or lactic acid buildup
Stool contains bicarb and severe diarhhea means prolonged loss of bicarbonate
- Renal disease: decrease production of bicarb
M. Acidosis Compensation
If there isn’t a problem with renal function, then the kidneys will attempt to produce more bicarbonate
However, usually the bicarbonate deficit exceeds the amount the kidneys can produce, so it is not enough.
- Respiratory compensates with hyperventilation but is weak
S/s of M. Acidosis
Kussmaul’s respirations?
Lethargy, fatigue, coma
Hypertension, dysrhythmias
- Hyperkalemia since potassium exchanges with hydorgen ions
M. Acidosis Tx
Treat the underlying cause
- If the kidneys are impaired, then hemodialysis is a priority
- If the patient is in a state of DKA, then insulin administration is a priority
- If the patient is in a type of shock state, then fluid replacement or other shock treatment is a priority
What can be done for hyperkalemia with M. Acidosis?
Insulin and D5, loop diuretics like fuerosimde, sodium polyestrene, and calcium gluconate
Metabolic Alkalosis Causes?
- Loss of hydrochloric acid from vomiting
- Gastric suctioning
- Bicarb gain esp in pts with renal insuffiency
M. Alkalosis Comp
Renal excretion of bicarbonate
Respiratory, decrease in respiratory rate
- Resp effect first
M. Alkalosis S/S
- hyperactive reflexes
- Parenthesia
- tetany
- seizures
- Resp depression
Tx for M. Alkalosis
-Adequate hydration
Good for prolonged vomiting or gastric suction
-0.9% sodium chloride
-Arginine hydrochloride
Raises chloride levels which are reduced from gastric suction or gastric loss
-A diuretic: Diamox (acetazolamide)
Carbonic anhydrase inhibitor, why would this help?
Carbonic anhydrase is the compnenet in the buffer system that causes bicarbonate to turn into carbonic acid
If it is inhibited, then bicarbonate is prevented from turning into carbonic acid and instead gets excreted.
Resp Acidosis CAuse
-Hypoventilation: Respirations < 12 per minute?
-Respiratory Failure
Injury to the Medulla
What is this?
CNS resp control center
Overdose of what types of medications?
Opiods, benzos, anything with sedative effects
Resp Acidosis Comp
Unlike metabolic processes where the kidneys can still try to compensate
Respiratory acid-base imbalances are due to impaired respiratory function
Compensation is only through renal compensation
Kidneys will retain bicarbonate ions or excrete hydrogen ions
Slow process to start
Resp Acidosis S/S
Mental status changes may occur first clinically Irritability Disorientation Lethargy Coma Headache
Tachycardia
TX for obstructive breathing condition with Resp Acidosis
Priority is to treat the underlying cause or what process is causing the reduced respiratory rate
For an obstructive type of breathing condition
Bi-level positive airway pressure (BiPAP)
Mechanical ventilation in more severe cases
TX for sedative med or overdoes that causes resp acidosis
Antidote for offending agent, what is an example?
Naloxone (Narcan) for opiod overdose
Other interventions to improve breathing depth and quality
Oxygen administration
Keeping the head of bed elevated
Antibiotics if pneumonia is involved
Resp Akalosis Cause
Acid deficit caused by hyperventilation or pulmonary disorders
What are some conditions that cause hyperventilation’s
Anxiety Fever Pain Trauma Anemia Asthma Pulmonary embolism Cerebrovascular accident or stroke
Resp Alkalosis Comp
Bicarbonate shifts into cells in exchange for Chloride ions
If alkalosis persists renal excretion of bicarbonate can happen
Resp Akalosis S/s
Neuromuscular symptoms
Paresthesia, dizziness, vertigo, tetany
Cardiovascular symptoms
Tachycardia, dysrhythmias, excessive diaphoresis
Resp Alkalosis Tx
Priority is fixing underlying cause
-If in pain or anxiety, an intervention that targets pain or anxiety
- If due to asthma, a bronchodilator
- If due to anemia, restoration of hemoglobin
