With prolonged acetazolamide at rest : ventilation +2.04 4.0 L/min ( P = .001 ) , tidal volume +0.11 1.13 L ( P = .003 ) , respiratory rate +1.24 4.63 breaths/min ( NS ) , end-tidal PO2 +4.62 2.43 mm Hg ( P = .001 ) , and end-tidal PCO2 -2.59 9.7 mm Hg ( P < .001 ) .