Algorithm Demonstrating a Diagnostic Approach to a Patient with Suspected Hypercapnia - Flowchart
Algorithm Demonstrating a Diagnostic Approach to a Patient with Suspected Hypercapnia - Flowchart Hypercapnia Hypercapnia
«Flowchart»

Suspected hypercapnia

Suspected hypercapnia

Suspected hypercapnia

Arterial blood gas

Arterial blood gas

Arterial blood gas

Hypercapnia

Hypercapnia

Hypercapnia

Continued clinical suspicion

Continued clinical suspicion

Continued clinical suspicion

Sea level PaCO2 >45 mm Hg or 6.0 kPA

Sea level PaCO2 >45 mm Hg or 6.0 kPA

Sea level PaCO2 >45 mm Hg or 6.0 kPA

CO 2

Yes

Yes

Yes

No

No

No

Yes

Yes

Yes

In-laboratory polysomnography with CO2 monitoring to assess for sleep hypoventilation

In-laboratory polysomnography with CO2 monitoring to assess for sleep hypoventilation

In-laboratory polysomnography with CO2 monitoring to assess for sleep hypoventilation

2

End

End

End

? Underlying cause

? Underlying cause

? Underlying cause

pH serum bicarbonate

pH serum bicarbonate

pH serum bicarbonate


pH high (>7.45)
Consider primary metabolic alkalosis or transient hyperventilation during arterial blood sampling (posthypercapnic alkalosis)


pH high (>7.45)
Consider primary metabolic alkalosis or transient hyperventilation during arterial blood sampling (posthypercapnic alkalosis)


pH high (>7.45)
Consider primary metabolic alkalosis or transient hyperventilation during arterial blood sampling (posthypercapnic alkalosis)
pH high (>7.45)


pH normal or near-normal
Serum HCO3– ↑3.5–5 mEq/L for !!triangle!!10 mm Hg ↑PaCO2


pH normal or near-normal
Serum HCO3– ↑3.5–5 mEq/L for !!triangle!!10 mm Hg ↑PaCO2


pH normal or near-normal
Serum HCO3– ↑3.5–5 mEq/L for !!triangle!!10 mm Hg ↑PaCO2 3 – ↑ ↑ CO 2 pH normal or near-normal


pH low (<7.35)
Serum HCO3– ↑1 mEq/L for !!triangle!!10 mm Hg ↑PaCO2


pH low (<7.35)
Serum HCO3– ↑1 mEq/L for !!triangle!!10 mm Hg ↑PaCO2


pH low (<7.35)
Serum HCO3– ↑1 mEq/L for !!triangle!!10 mm Hg ↑PaCO2 3 – ↑ ↑ CO 2 pH low (<7.35)

Chronic hypercapnia

Chronic hypercapnia

Chronic hypercapnia

Acute hypercapnia

Acute hypercapnia

Acute hypercapnia

Alveolar-arterial PO2 difference

Alveolar-arterial PO2 difference

Alveolar-arterial PO2 difference

O 2


Normal alveolar-arterial PO2 difference disorders of the central respiratory controller disorders of the respiratory system effectors


Normal alveolar-arterial PO2 difference disorders of the central respiratory controller disorders of the respiratory system effectors


Normal alveolar-arterial PO2 difference disorders of the central respiratory controller disorders of the respiratory system effectors O 2 Normal alveolar-arterial


High alveolar-arterial PO2 difference disorders of the pulmonary parenchyma, airways and vasculature


High alveolar-arterial PO2 difference disorders of the pulmonary parenchyma, airways and vasculature


High alveolar-arterial PO2 difference disorders of the pulmonary parenchyma, airways and vasculature O 2 High alveolar-arterial