Table 1.

Effects of hypoxia on blood P_O2, P_CO2 and pH

	Condition	Trial 1: phentolamine	Trial 2: phentolamine and propranolol	Trial 3: phentolamine propranolol and l-NMMA
PO2 (mmHg)	Normoxia	88.9 ± 1.9	86.4 ± 2.2	89.1 ± 3.7
	Hypoxia	42.2 ± 1.4 *	43.8 ± 2.0 *	44.1 ± 1.8 *
PCO2 (mmHg)	Normoxia	40.8 ± 1.2	35.8 ± 5.0	39.8 ± 1.4
	Hypoxia	37.6 ± 1.3	37.7 ± 1.2	37.5 ± 1.8
End-tidal CO2 (%)	Normoxia	6.2 ± 0.4	6.2 ± 0.4	6.1 ± 0.4
	Hypoxia	5.8 ± 0.4 *	5.8 ± 0.4 *	5.8 ± 0.4 *
pH	Normoxia	7.39 ± 0.01	7.38 ± 0.01	7.38 ± 0.01
	Hypoxia	7.41 ± 0.01 *	7.42 ± 0.01 *	7.41 ± 0.01 *
Hb saturation (%)	Normoxia	96.6 ± 0.3	96.1 ± 0.2	96.5 ± 0.6
	Hypoxia	77.9 ± 1.7 *	79.8 ± 2.0 *	80.3 ± 2.0 *

Hb, haemoglobin.

^*P <0.005, Hypoxia vs. Normoxia.