Respiratory System (Acid) CO2 is a volatile acid
Change |
•The respiratory system can effect a change in 15-30 minutes |
ACIDOSIS |
• Decrease your respiratory rate (hypoventilation) you retain CO2 (acid) therefore increasing your CO2 (acid) |
ALKLAOSIS |
• Increased respiratory rate (hyperventilation) "blow off" CO2 (acid) therefore decreasing CO2 acid |
The Renal System (Base)
Renal System (Base) |
• Kidneys rid the body of the nonvolatile acids H+ (hydrogen ions) and maintain a constant bicarb (HCO3).
• Bicarbonate is the body’s base |
Acidosis |
• Kidneys try to adjust for this by excreting H+ and retaining HCO3- base.
• Respiratory System will try to compensate by increasing ventilation to blow off CO2 (acid) and therefore decrease the Acidosis.
• Have excess H+ and decreased HCO3- causing a decrease in pH. |
Alkalosis |
• H+ decreases and you have excess (or increased) HCO3- base.
• The kidneys excrete HCO3- (base) and retain H+ to compensate.
• The respiratory system tries to compensates with hypoventilation to retain CO2 (acid) to decrease the alkalosis |
Change |
• The renal system takes several hours to days to have an effect. |
The Land of the ABG
The Last Name |
• First, look at her pH (normal is 7.35 - 7.45)
• If her pH is < 7.35; her name is ACIDOSIS
• If her pH is > 7.45; her last name is ALKALOSIS
• NOTE: To have an absolutely perfect last name; her pH needs to be 7.40. So, keep in mind that if her pH is 7.35 - 7.39 she’s thinking about marrying into the ACIDOSIS family. If her pH is 7.41 - 7.45 she’s thinking about marrying into the ALKALOSIS family |
The First Name |
• Look at her pH again.
• If it is 7.35 - 7.45 (normal) then her first name is COMPENSATED.
• If the pH is < 7.35 or > 7.45 then her first name is UNCOMPENSATED. |
The Middle Name |
• First you need to look at the CO2 and HCO3-. Remember : normal CO2 35 - 45; and HCO3- 22 - 26. 1.
• The middle name will either be Respiratory or Metabolic. 2.
• If the CO2 is < 35 or > 45 her middle name is RESPIRATORY. 3.
• If the HCO3- is < 22 or > 26; her middle name is METABOLIC. |
The Family Feud |
• pH and HCO3- are "kissin’ cousins" they like to go in the same direction
• CO2 is the "black sheep" pH runs the opposite direction when it sees him Coming. THEREFORE:
• Decreased pH with decreased HCO3-: ACIDOSIS
• Increased pH with increased HCO3-: ALKALOSIS
• Decreased pH with increased CO2-: ACIDOSIS
• Increased pH with decreased CO2-: ALKALOSIS |
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Metabolic Acidosis
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• pH < 7.35 (Normal: 7.35 - 7.45) HCO3- < 22 (normal: 22 – 26) |
Causes |
• Increased H+, excess loss of HCO3-
• Overproduction of organic acids (starvation, ketoacidosis, increased catabolism)
• Impaired renal excretion of acid (renal failure)
• Abnormal loss of HCO3- (diarrhea, biliary fistula, Diamox)
• Ingestion of acid (salicylate overdose, oral anti-freeze) |
Signs and Symptoms |
• CNS depression (confusion to coma)
• Cardiac Dysrhythmias (elevated T wave, wide QRS to ventricular standstill)
• Electrolyte abnormalities (elevated K+, Cl-, Ca2+)
• Flushed skin (arteriolar dilitation)
• Nausea |
Treatment (treat the underlying cause) |
• NaHCO3- (sodium bicarbonate) based on ABGs only and with caution
• IV fluids and insulin for DKA
• Dialysis for renal failure
• Antibiotics, increased nutrition for tissue catabolism
• Increased cardiac output and tissue perfusion for low CO states
• Rehydrate, monitor I and O
• Treat dysrhythmias, support hemodynamic and respiratory status |
Metabolic Alkalosis
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• pH > 7.45 (Normal: 7.35 - 7.45) HCO3- > 26 |
Causes |
• Loss of H+ or increased HCO3-
• Loss of K+ (diarrhea, vomiting)
• Ingestion of large amounts of bicarbonate (antacids, resuscitation)
• Prolonged use of diuretics (distal tubule lose ability to reabsorb Na+ and Cl- therefore NaCl); Ammonia is in the urine and then binds with H+ |
Signs and Symptoms |
• Similar to the disease process
• Diaphoresis
• Nausea and Vomiting
• Increase neuromuscular excitability (Ca2+ binds with protein)
• Shallow breathing (respiratory compensation)
• EKG changes (increased QT, sinus tachycardia)
• May also see confusion progressing to lethargy to coma
• Electrolyte abnormality (decreased Ca2+), normal or decreased K+, increased base excess on the ABG |
Treatment (treat the underlying cause) |
• Replace potassium (KCl) losses in 0.9% NaCl (rehydrates and increases HCO3- excretion)
• Diamox (acetazolamide, increases HCO3-excretion)
• Monitor neuro status, re-orient, seizure precaution, monitor I and O |
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RESPIRATORY ACIDOSIS
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• pH < 7.35 (Normal: 7.35 - 7.45) CO2 > 45 (Normal: 35 – 45) |
Causes |
• Hypoventilation • Depression of the Respiratory Center (sedatives, narcotics, drug overdose, CVA, cardiac arrest, MI).
• Respiratory muscle paralysis (spinal cord injury, Guillian-Barre, paralytics).
• Chest wall disorders (flail chest, pneumothorax).
• Disorders of the lung parenchyma (CHF, COPD, pneumonia, aspiration, ARDS).
• Alteration in the function of the abdominal system (distension) |
Signs and Symptoms |
•CNS depression (decreased LOC)
•Muscle twitching which can progress to convulsions
•Dysrhythmias, tachycardia, diaphoresis (related to hypoxia secondary to hypoventilation)
•Palpitations
•Flushed skin
•Serum electrolyte abnormalities including elevated K+ (potassium leaves the cell to replace the H+ buffers leaving the cell) |
Treatment |
•Physically stimulate the patient to improve ventilation
•Vigorous pulmonary toilet (chest PT, coughing and deep breathing, inspirometer, respiratory treatments with bronchodilators)
•Mechanical ventilation (to increase the respiratory rate and tidal volume)
•Reversal of sedatives and narcotics
•Antibiotics for infections
•Diuretics for fluid overload
•NOTE: beware of NaHCO3- sodium bicarbonate—can compensate and cause metabolic alkalosis. Also, if patient has been hypoxic and this is a lactic acidosis; NaHCO3- can be dangerous) |
Respiratory Alkalosis
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pH > 7.45 (Normal: 7.35 - 7.45) CO2 < 35 (Normal: 35 – 45) |
Causes |
• Alveolar Hyperventilation
•Psychogenic (fear, pain, anxiety)
•CNS stimulation (brain injury, ETOH, early salicylate poisoning, brain tumor)
•Hypermetabolic states (fever, thyrotoxicosis)
•Hypoxia (high altitude, pneumonia, heart failure, pulmonary embolism)
•Mechanical overventilation (ventilator rate too fast) |
Signs and Symptoms |
•Heachache
•Vertigo
•Paresthesias (numb fingers /toes, circumoral, carpal pedal spasms and tetany)
•Tinnitus (ringing in the ears)
•Electrolyte abnormalities (decreased Ca+, K+) |
Treatment (treat the underlying cause) |
•Sedatives or analgesics
•Correction of hypoxia (possible diuretics, mechanical ventilation to also decrease respiratory rate and decrease the tidal volume)
•NOTE: patients with brain injury may need hyperventilation
•Antipyretics for fever
•Treat hyperthyroidism
•Breathe into a paper bag for hyperventilation |
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