Acid-Base Balance (Imbalances) Nursing: ABGS, Acidosis vs Alkalosis - Respiratory & Metabolic
RegisteredNurseRN・65 minutes read
Respiratory acidosis is caused by decreased lung ventilation and excessive CO2 retention, leading to low blood pH, while metabolic acidosis results from an excess of acids in the body. Proper interpretation of arterial blood gas values and understanding acid-base imbalances are essential for identifying and treating respiratory and metabolic acidosis effectively.
Insights
- Respiratory acidosis is caused by decreased lung ventilation, leading to CO2 retention and a drop in blood pH, with symptoms like neurostatus changes and hypoxia.
- Chronic COPD patients are prone to chronic acidosis due to CO2 retention, requiring careful oxygen administration, and monitoring ECG is vital to detect potential dysrhythmias from acidosis.
- Metabolic acidosis results from excess acids or impaired elimination, with ABG values showing low blood pH, bicarb levels, and potentially low P2 levels, necessitating interventions like administering sodium bicarb or normal saline.
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Recent questions
What causes respiratory acidosis?
CO2 retention from decreased lung ventilation.
What are the symptoms of respiratory acidosis?
Neurostatus changes, hypoxia, increased heart rate.
How is respiratory alkalosis diagnosed?
Arterial blood CO2 levels below 35 mm of mercury.
What are the interventions for metabolic acidosis?
Administering sodium bicarb or normal saline.
How does the renal system regulate acid-base balance?
By conserving or excreting acids to maintain pH levels.
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Summary
00:00
Understanding Respiratory Acidosis: Causes, Symptoms, Treatment
- Respiratory acidosis occurs due to decreased lung ventilation, leading to CO2 retention and a drop in blood pH.
- Causes of respiratory acidosis include slow breathing rates (less than 12 breaths per minute in adults), damage to gas exchange structures in the lungs, and weak respiratory muscles.
- Carbon dioxide, a waste product from cell metabolism, needs to be within a specific range (35 to 45 mm of mercury) to maintain balance.
- In respiratory acidosis, excess CO2 binds with water to form carbonic acid, which breaks down into hydrogen ions, affecting blood pH.
- Conditions like drug use, neuromuscular diseases, pulmonary edema, pneumonia, brain damage, asthma, bronchial spasms, and COPD can lead to CO2 retention.
- Patients with chronic COPD are chronic acidosis sufferers due to CO2 retention, requiring careful oxygen administration.
- Arterial blood gas values in respiratory acidosis show a blood pH below 7.35, CO2 levels above 45 mm of mercury, and bicarb levels indicating compensation.
- Symptoms of respiratory acidosis include neurostatus changes, hypoxia, increased heart rate, and low blood pressure.
- Nurses caring for patients with respiratory acidosis should monitor oxygen levels, respiratory status, neuro status, and electrolytes, administer oxygen cautiously, encourage coughing and deep breathing, suction if needed, provide mouth care, use bronchodilators, monitor medications affecting breathing, and watch for electrolyte imbalances affecting the heart.
- Monitoring ECG is crucial to detect any dysrhythmias due to potential hyperkalemia from acidosis.
14:32
Respiratory Alkalosis: Causes, Symptoms, and Interventions
- Respiratory alkalosis occurs due to increased lung ventilation, leading to a drop in CO2 levels and an increase in pH levels, resulting in an alkalic state in the body.
- Tachypnea, defined as a fast respiratory rate exceeding 20 breaths per minute in adults, is a primary cause of respiratory alkalosis, as rapid breathing leads to excessive CO2 exhalation.
- Various conditions like fever, aspirin toxicity, excessive controlled ventilation, hyperventilation due to anxiety, pain, pneumothorax, and neuro changes can cause tachypnea and subsequently respiratory alkalosis.
- Arterial blood CO2 concentration levels below 35 mm of mercury indicate alkalosis, while bicarbonate (HCO3) levels below 22 or above 26 mil equivalents per liter suggest acidosis or alkalosis, respectively.
- In cases of respiratory alkalosis, the body may exhibit uncompensated or partial compensation, with the kidneys playing a crucial role in balancing acids and bases to regulate blood pH levels.
- Symptoms of respiratory alkalosis include increased respiratory rate, neuro changes like anxiety and dizziness, elevated heart rate, and potential electrolyte imbalances such as hypocalcemia and hypokalemia.
- Interventions for respiratory alkalosis involve identifying and addressing the underlying cause, reducing the respiratory rate, monitoring electrolytes, administering sedatives or anti-anxiety medications, and teaching relaxation techniques to prevent hyperventilation.
- Metabolic acidosis results from an excess of acids in the body or the inability to eliminate them, with causes including lactate accumulation, chronic diarrhea, impaired renal function, diabetic ketoacidosis, and salicylate toxicity.
- The body's acid-base balance is maintained through the neutralization of acids by bases, with hydrogen ions playing a crucial role in determining blood pH levels within the range of 7.35 to 7.45.
- The respiratory and renal systems work together to regulate carbonic acid levels, with the respiratory system controlling CO2 levels through breathing rate and depth, while the renal system helps conserve or excrete acids to maintain the acid-base balance.
30:40
Managing Acid-Base Imbalances in Patients
- The respiratory system quickly adjusts blood pH, while the renal system takes longer but effectively balances acids and bases over days.
- The renal system can retain bicarb to neutralize acids in conditions like metabolic acidosis.
- Arterial blood gas (ABG) results show low blood pH (<7.35), low bicarb levels (<22), and potentially low P2 levels (<35) in metabolic acidosis.
- Patients with metabolic acidosis exhibit rapid, deep breathing, confusion, weakness, altered blood pressure, and abnormal ECG T-waves.
- Nursing interventions for metabolic acidosis include identifying and treating the cause, administering sodium bicarb or normal saline, and considering dialysis for renal failure.
- Metabolic alkalosis results in elevated blood pH and bicarbonate levels due to acid loss or increased bases like bicarbonate.
- Conditions leading to metabolic alkalosis include acid loss, low chloride levels, potassium loss, aldosterone increase, loop/thiazide diuretics, and excess sodium bicarb IV.
- Bases like bicarbonate neutralize acids by binding with hydrogen ions, increasing pH levels.
- The respiratory system adjusts carbon dioxide levels by altering respiratory rate and depth, while the renal system retains hydrogen ions to counter metabolic alkalosis.
- ABG results in metabolic alkalosis show high blood pH (>7.45), elevated bicarbonate levels (>26), and potentially normal or elevated P2 levels (>45), with symptoms like slow respirations, ECG changes, and hypokalemia.
46:41
"Modified Allen Test and ABG Interpretation"
- To perform the modified Allen test, turn the patient's hand so the Palm faces up and have them make a clinched fist.
- Locate the radial and oler artery and apply firm pressure to both simultaneously with thumbs or fingertips to stop blood flow temporarily.
- Have the patient open and close their hand, observing the hand losing color and appearing lighter or blanched.
- Release pressure on the oler artery but maintain it on the radial artery, then assess the return of blood flow to the hand.
- A normal response shows the hand returning to normal color within less than 5 seconds, indicating the radial artery is suitable for arterial blood gas collection.
- The Tic-Tac toe method simplifies solving arterial blood gas problems by setting up a grid with acid, normal, and base columns.
- Input arterial blood gas values like P2, bicarbon, and pH into the grid, identifying a vertical three in a row to determine the acid-base imbalance.
- Understanding ABG results involves interpreting blood pH, P2, and bicarbonate levels to recognize acidosis or alkalosis.
- Remember that P2 values for the respiratory system are opposite in interpretation to pH and bicarbonate levels.
- Practice solving ABG problems using the Tic-Tac toe method and understanding compensation types like uncompensated, partial, or full compensation.
01:01:45
Interpreting ABG Values Using Rome Method
- Blood pH of 7.40 is considered normal, but it can be either acidic or alkalic.
- Less than 7.40 is acidotic normal, while greater than 7.40 is alkalic normal.
- A blood pH of 7.36 indicates normality but leans towards acidity.
- In respiratory acidosis, P2 is under acid, and HCO3 is under base.
- The Rome method aids in solving ABG problems, with "R" and "O" representing respiratory and "M" and "E" representing metabolic.
- Respiratory opposite and metabolic equal are key concepts in the Rome method.
- Normal blood pH ranges from 7.35 to 7.45, with values below 7.35 considered acidic and above 7.45 considered basic.
- P2 levels of 35 to 45 mm of mercury are normal, with values above 45 indicating acidity and below 35 indicating alkalinity.
- HCO3 levels of 22 to 26 Milli equivalent are normal, with values below 22 being acidic and above 26 being basic.
- Understanding the Rome method and normal ranges for blood pH, P2, and HCO3 is crucial in interpreting ABG values accurately.
