From the Guidelines
A CO2 level of 43 mmHg is within the normal range (34-46 mmHg) and does not require immediate intervention if the patient is stable and asymptomatic. Management of a patient with this CO2 level requires first determining if this represents acute or chronic hypercapnia and identifying the underlying cause. Initial steps include assessing oxygenation with pulse oximetry and arterial blood gases, evaluating respiratory rate and effort, and checking for signs of respiratory distress. For patients with COPD or other chronic respiratory conditions, this CO2 level may represent their baseline. Treatment focuses on addressing the underlying cause, which may include bronchodilators like albuterol (2.5 mg via nebulizer every 4-6 hours) or ipratropium (500 mcg via nebulizer every 6-8 hours) for bronchoconstriction, antibiotics for respiratory infections, or diuretics like furosemide (20-40 mg IV/PO) for fluid overload, as suggested by the BTS guideline for oxygen use in adults in healthcare and emergency settings 1.
Some key points to consider in the management of these patients include:
- Using a 24% Venturi mask at 2–3 L/min or a 28% Venturi mask at 4 L/min to achieve an oxygen saturation of 88-92% in patients with COPD or other conditions that may cause hypercapnic respiratory failure, as recommended by the BTS guideline 1.
- Considering noninvasive ventilation with BiPAP (initial settings: IPAP 10-12 cmH2O, EPAP 4-5 cmH2O) for patients showing signs of respiratory fatigue.
- Mechanical ventilation is reserved for severe respiratory failure.
- The goal is to improve ventilation while treating the underlying condition, as CO2 retention results from inadequate gas exchange due to ventilation-perfusion mismatch, decreased respiratory drive, or increased CO2 production, as explained in the BTS guideline for oxygen use in adults in healthcare and emergency settings 1.
It is essential to note that the management of patients with hypercapnia should be individualized, and the treatment should be based on the results of previous blood gas estimations during acute exacerbations, as recommended by the BTS guideline 1.
From the Research
Management Steps for a Patient with a Carbon Dioxide (CO2) Level of 43 mmHg
- The patient's CO2 level is slightly elevated, which may indicate respiratory acidosis or other respiratory issues 2.
- The following steps can be taken to manage the patient:
- Monitor the patient's arterial blood gases (ABGs) to assess the severity of the respiratory issue 3, 4.
- Use non-invasive positive pressure ventilation (NPPV) to improve the patient's respiratory function, especially if they have chronic obstructive pulmonary disease (COPD) 4, 5.
- Monitor the patient's transcutaneous CO2 (Ptc,CO2) levels to estimate their arterial CO2 levels, but note that this method may have instrumental bias and require mathematical correction 6.
- Consider using PetCO2 monitoring in conjunction with NPPV treatment to guide respiratory care and improve patient outcomes 5.
- If the patient has significant hypercarbia (pCO2 > 50 mmHg), consider using venous pCO2 levels as a screening tool, with a cutoff value of 45 mmHg 2.
Considerations for Patients with COPD
- Patients with COPD may experience a progressive decline in lung function, leading to increased CO2 levels and respiratory failure 3.
- Regular treatment with bronchodilators and other medications can help slow the progression of COPD and improve respiratory function 3.
- NPPV can be an effective treatment for patients with COPD and respiratory failure, but it should be used cautiously and under close monitoring 4.