Table 2.

Effect of dobutamine on apnoeas during normoxia and hypoxia

	Normoxia				Hypoxia
	Placebo	D2.5	D7.5	P (anova)	Placebo	D2.5	D7.5	P (anova)
Duration, s	43 ± 3	35 ± 2†	28 ± 3*	<0.05	21 ± 2	17 ± 1†	15 ± 1*	<0.01
ΔMSNA, %	251 ± 34	372 ± 50†	585 ± 101*	<0.05	290 ± 43	360 ± 21†	537 ± 69*	<0.05
Sa O2,%	93 ± 0.8	95 ± 2	95 ± 1	NS	76 ± 2	82 ± 3†	88 ± 2*	<0.01
HR, beats min−1	69 ± 2	70 ± 4	76 ± 3*	<0.05	83 ± 6	92 ± 5	98 ± 3*	<0.05

Results are expressed as mean ± SD; n = 17 subjects except for muscle sympathetic nerve activity (MSNA) measurements, where n = 11 subjects. DMSNA, Changes in MSNA; MABP, mean arterial blood pressure; HR, heart rate; Sa O₂%, arterial O₂ saturation.

^†P < 0.05 for D2.5 vs. placebo

^*P < 0.05 for D7.5 vs. D2.5.