Arterial Blood Gas Flashcards
What is the normal pH range?
pH 7.35 to 7.45
When is the blood acidic?
when it is below pH 7.35
When is the blood alkalotic?
when the pH is above 7.45
Significant changes in the blood pH above ___ or below ___ will interfere with cellular ____, and if uncorrected will lead to ____.
above 7.8 or below 6.8
interfere with cell functioning
cell death
Describe the Respiratory Buffer Response
when there is too much or too little CO2 in the blood - meaning there is a change in pH - it triggers the lungs to either INCREASE or DECREASE the rate and depth of ventilation. This happens until the appropriate amount of CO2 has been re-established. Activation of lungs occurs within 1 to 3min.
Describe Renal Buffer response
when there is a change in pH level in the blood, the kidneys will either retain or excrete bicarbonate HCO 3- . As the pH decreases, the kidneys will compensate by retaining HCO 3-. As the pH rises the kidneys will excrete HCO3- through urine. This occurs slowly, hours or days to occur.
Respiratory acidosis is defined as?
pH less than 7.35 and PaCo2 greater than 45 mm Hg.
What causes respiratory acidosis?
Accumulation of CO2 causes respiratory acidosis, which combines with water in body to produce carbonic acid, thus lowering the pH of blood. Any condition that results in hypoventilation can cause this *
What are some conditions that can cause respiratory acidosis?
- CNS depression related to head injury
- CNS depression related to medications (narcotics, sedatives, or anesthesia)
- Impaired resp muscle function related to SCI, neuromuscular diseases or neuromuscular blocking drugs
- pulmonary disorders (atelectasis, pneumonia, pneumothorax, pulmonary edema, bronchial obstruction)
- massive pulmonary embolus
- Hypoventilation due to pain, chest wall injury/deformity, abdominal distension.
What are some signs and symptoms of respiratory acidosis?
Pulmonary: -dyspnea -respiratory distress -shallow respirations Nervous system: -headache -restlessness -confusion for extreme* - drowsiness and unresponsiveness Cardio: - tachycardia -dysrhythmias
What will correct resp acidosis?
Increasing ventilation
What is Respiratory Alkalosis?
Defined as a pH greater than 7.45 and PaCo2 less than 35 mm Hg.
Respiratory Alkalosis conditions?
Any condition causing hyperventilation can result in this.
- Psychological responses (anxiety, fear)
- Pain
- Inc metabolic demands (fever, sepsis, pregnancy, thyrotoxicosis)
- Medications such as resp stimulants
- CNS lesions
What are signs and symptoms of Respiratory alkalosis?
Nervous system: -light headedness -numbness -tingling -confusion -inability to concentrate -blurred vision Cardiac: -dysrhythmias -tetanic spasms of arms and legs
What is Metabolic acidosis?
Defined as a bicarbonate (HCO3-) level of less than
22 mEq/L with a pH of less than 7.35.
What causes a metabolic acidosis?
caused by either a deficit of base in the blood, or an excess of acids, other than CO2. Diarrhea or fistulas may cause dec levels of base.
increase of acids:
- renal failure
- diabetic ketoacidosis
- anaerobic metabolism
- starvation
- salicylate intoxication - NSAIDS
What are symptoms of metabolic acidosis?
Nervous S: -headache -confusion -restlessness progressing to lethargy -stupor or coma Cardiac: -dysrhythmias -Kussmaul respirations (deep and labored breathing) - in an effort to blow off more CO2 - warm and flushed skin, as well as nausea and vomiting are commonly noted*
What us hypoxemia?
low oxygen level in the blood
What is hypoxia?
deficiency in amount of O2 reaching the tissues
What is perfusion?
blood flow through capillary bed
what is lethargy?
lack of energy and enthusiasm
What is stupor?
state of near unconsciousness or insensibility
What is metabolic alkalosis?
Bicarbonate level greater than 26 mEq/ L with a pH greater than 7.45.
Why does metabolic alkalosis occur?
either an excess of base or a loss of acid within body.
Excess of base occurs from ingestion of antacids, excess use of bicarbonate, or use of lactate in dialysis. Loss of acids occur secondary to protracted vomiting, gastric suction, hypochloremia, excess administration of diuretics or high levels of aldosterone
