To take the degree of alveolar ventilation into account in the assessment of arterial Pa02, many investigators calculate the alveolai^arterial oxygen pressure difference. This requires an estimation of the respiratory quotient, which varies during work. A simple descriptive way of accounting for ventilation is to sum Pa02 and PaC02. In scleroderma, a good negative correlation was found between the alveolar-arterial gradient and (Pa02 + PaCOJ at rest. According to our clinical experience, (Pa02 + PaC02) may be a more sensitive parameter than Pa02 alone. In the present study, this is exemplified by comparing blood gas data between symptomatic and asymptomatic individuals and between the entire group of stage 3 patients and stage 2. ampicillin antibiotic
The high dyspneic index highlights the importance of lung function as a limiting factor for working capacity pointed out by others. The index represents the quotient between exercise ventilation and FEV!. The reduction in FEV! reflects both low compliance and high resistance. A high exercise ventilation reflects, to some extent, an “excess ventilation” as PaC02 was low. It is also due to a high breathing frequency, which gives an increased deadspace ratio (Vd/Vt).