Blood gases at rest and during exercise in patients with α1-Pi deficiency

• Published in: Respiratory medicine 2000-12, Vol.94 (12), p.1177-1183
• Main Authors: WENCKER, M., KONIETZKO, N.
• Format: Article
• Language: English
• Subjects: Biological and medical sciences; blood gases; emphysema; Errors of metabolism; exercise testing; FEV1; lung function test; Medical sciences; Metabolic diseases; Proteins and glycoproteins; α1-Pi deficiency
• ISSN: 0954-6111; 1532-3064
• DOI: 10.1053/rmed.2000.0947

α1-protease inhibitor (Pi) deficiency is associated with a protease–anti-protease imbalance leading to premature destruction of lung tissue and early emphysema. Little is known about the blood gases of these patients in the various stages of the disease. The purpose of this study was to evaluate blood gases in patients with α1-Pi deficiency when patients were at rest and during exercise, and to correlate these with lung function measurements. A total of 369 patients with severe α1-Pi deficiency had pulmonary function test and blood gas analysis, 282 also had blood gases taken during steady state submaximal exercise testing. Only 21% of the patients had normal blood gases at rest; 71% had mild hypoxaemia; 8% had severe hypoxaemia. Surprisingly, 61% of the patients with mild lung disease and a FEV1of more than 65% predicted were hypoxaemic. During exercise 65% of the patients had a drop in PO2of more than 0·40 kPa. FEV1was a significant predictor for the PO2values at rest and during exercise. During exercise the arterial–alveolar gradient increased in about 50% and decreased in 25% of the patients. Many patients with α1-Pi have blood gas abnormalities. Impaired blood gases in early stages of the disease result in a discrepancy between lung function parameters and blood gases. FEV1measurements inadequately capture the extent of lung disease in patients with α1-Pi deficiency, and both blood gases at rest and during exercise are needed in the assessment of all stages of the disease.