Respiratory Acidosis - EXAM 3 Flashcards
Normal pH
7.35-7.45
Normal PaCO2
35-45
Normal HCO3 (bicarbonate)
24-30
Normal PaO2
75-100
Hypoxemic Respiratory Failure
- Inadequate transfer between alveoli and pulmonary capillary beds
- PaO2 less than or equal to 60 mm Hg on 60% O2
Room air oxygen level
21%
Hypercapnic Respiratory Failure
- Most common ABG abnormality
- Insufficient CO2 removal
- PaCO2 greater than 45 mm Hg
- pH less than 7.35
Causes of Hypoxemic Respiratory Failure
- Intrapulmonary shunting
- Pneumonia
- Smoke inhalation
- Shock
- ARDS
- V-Q mismatch
- PE
Intrapulmonary shunting
Blood exits lung without participating in gas exchange
- Pnrumonis secretions
- Mucus Plug
- Blood clot from PE
- ARDS: Acute Respiratory Distress Syndrome
Hypercapnic Respiratory Failure
- Obstructive airway diseases (asthma, COPD, difficulty getting air out)
- CNS impairment
- Chest wall dysfunction (problems getting air in)
- Neuromuscular dysfunction
- Narcotics, sedatives, barbiturates
What is the respiratory compensatory component?
carbonic acid
What is the renal compensatory component?
bicarb
Respiratory center
In brain. Detects lungs to increase or decrease RR and depth in a response to the amount of CO2. CO2 is retained or blown off.
How fast does compensation occur?
System is extremely sensitive to changes in pH and compensation begins in seconds to minutes
Renal Regulation of Acid Base Balance
- Control buffer NaHCO3 (sodium bicarb)
- Takes several hours to days to kick in
- Can control HCO3 (bicarb) by either reabsorbing or excreting H+ ions
Respiratory Acidosis Diagnostic Findings
- pH below 7.35
- PaCO2 above 45 mm Hg
- HCO3 is normal (24-30)
- Hyperkalemia
- Hypercalcemia
- Lactic acid accumulation
- Low PaO2
Pulmonary Function Tests
- Decreased tidal volume
- Decreased FVC
- Decreased FEV 1
- Decreased minute ventilation
- End tidal CO2 (ETCO2)
Respiratory acidosis assessment data
- Change in LOC/altered MS/headache
- Progressive sleepiness as CO2 levels increase
- Dyspnea
- Rapid, shallow breathing with increased work of breathing (hypoventilation in the end)
- Patient with HOB up at least 45 degrees
- Leading to decreased RR and respiratory muscle fatigue (emergency)
- Hypertension
- Tachycardia
- Dysrhythmia
Acid-Base Compensation
- The respiratory system attempts to compensate for respiratory acidosis
- Increased the rate and depth of respirations to blow off CO2
- The renal system also attempts to compensate for respiratory acidosis…slower process
- Kidneys begin eliminating H+ ions and retaining HCO3
- HCO3 levels rise to buffer
- If no renal compensation is evident in the ABG analysis, the resp. problem is acute
- Over time, the kidneys compensate by retaining bicarbonate and secreting hydrogen ions
- If compensation is evident in the ABG analysis, the resp. problem is chronic
- A compensated ABG differs from a normal ABG in that PaCO2 and HCO3 will both be abnormal and the pH with be normal
What’s the relationship between acid-base compensation and correction?
- Acidosis can be temporarily corrected by the medical team by administering NaHCO3
- Compensation occurs within the body through the effects of the respiratory and renal systems
Medical Supportive Therapy
- Correct underlying cause of resp. failure
- Manage and maintain adequate cardiac output
- Maintenance of adequate hemoglobin concentration
Respiratory Therapy
- Intubation with mechanical ventilation (R. failure)
- Non-invasive positive pressure ventilation
- O2 therapy
- Pulmonary toliet = effective cough, incentive spirometry, hydration/humidification, cchest physiotherapy, airway suctioning
Medication Therapy
- Relief of bronchospasm
- Reduction of airway inflammation
- Reduction of pulmonary congestion (lasix)
- Treatment of pulmonary infections
- Reduction of severe anxiety (lorazepam)
Nutritional Therapy
- Parenteral nutritional support
- Enteral nutritional support
- Need adequate calories and protein
- May need to limit carbohydrates in patient who retains CO2
Therapeutic Nursing Interventions
- Assess LOC
- Monitor adequacy of ventilation respiratory status: administer supplemental O2
- Monitor cardiovascular status
- Adequate fluids to liquefy secretions and maintain cardiac output
- Encourage patient to cough/augment cough/suction (pulmonary toliet)
- Administer and monitor response to medication therapy
- Administer and assess safe nutritional intake
- Prevent infection
- Support patient and family
- Education
Gerontological Considerations
- Physiologic aging of lung brings loss of effective alveoli and loss of surface area for gas exchange in alveoli
- Decrease in ciliary activity
- Decrease in resp. muscle strength
- Greater vulnerability for resp. acidosis and resp. failure
