Table 4

Mean (SD) physiological measurements during the two hour study period

On arrivalBaseline20 minutes40 minutes60 minutes80 minutes100 minutes120 minutes
Heart rate (bpm)
Control110 (23)101 (24)100 (24)98 (24)94 (27)90 (24)87 (22)91 (21)
CPAP113 (18)104 (18)103 (21)97 (24)97 (24)95 (26)94 (24)91 (23)
Bilevel110 (23)106 (24)103 (32)96 (29)95 (27)89 (25)93 (29)92 (25)
Respiratory rate (bpm)
Control36 (7)30 (6)29 (5)28 (7)26 (6)25 (6)24 (7)24 (7)
CPAP35 (6)28 (8)28 (8)23 (7)24 (8)22 (7)21 (6)21 (7)
Bilevel35 (8)30 (6)25 (8)24 (7)24 (6)22 (7)20 (6)20 (6)
Systolic BP (mm Hg)
Control165 (42)146 (38)129 (32)124 (22)121 (25)117 (17)114 (22)121 (17)
CPAP166 (42)164 (41)138 (32)128 (28)132 (26)127 (18)126 (19)120 (21)
Bilevel166 (34)155 (33)136 (33)127 (33)127 (30)125 (27)128 (25)114 (33)
Diastolic BP (mm Hg)
Control92 (21)78 (21)67 (17)65 (14)64 (11)63 (8)58 (14)66 (14)
CPAP93 (25)89 (22)74 (16)71 (16)73 (17)70 (15)67 (11)61 (11)
Bilevel92 (16)81 (17)74 (19)67 (19)67 (17)65 (13)64 (13)64 (16)
Arterial H+ ion concentration (nmol/l)
Control63.47 (11.33)46.19 (12.27)45.29 (4.43)
CPAP68.76 (17.86)53.08 (12.70)48.84 (9.85)
Bilevel62.16 (11.20)50.67 (12.75)45.96 (10.05)
Arterial pH
Control7.20 (0.08)7.32 (0.05)7.35 (0.04)
CPAP7.18 (0.11)7.29 (0.10)7.32 (0.08)
Bilevel7.21 (0.07)7.31 (0.09)7.35 (0.08)
po2 (kPA)
Control13.45 (7.23)12.83 (4.93)13.27 (4.96)
CPAP13.75 (9.19)9.02 (2.41)11.16 (3.86)
Bilevel12.49 (5.75)11.19 (4.47)12.77 (6.23)
pco2 (kPA)
Control7.44 (2.33)5.99 (1.47)5.74 (1.30)
CPAP9.21 (2.56)7.39 (2.76)6.76 (1.95)
Bilevel8.01 (2.28)6.67 (2.28)6.00 (1.60)
Sao2 (%)
Control91.3 (8.2)95.0 (3.7)96.1 (3.3)
CPAP88.8 (10.9)89.9 (5.7)93.6 (5.9)
Bilevel89.7 (12.1)92.3 (7.0)94.9 (4.7)