Table 3—

Overnight sleep parameters, heart rate variability(HRV) and compliance following treatment with standard noninvasive ventilation (NIV) and autotitrating NIV

VariableStandard NIVAutotitrating NIVDifference (95% CI)p-value
Subjects n2020
Mean overnight Sa,O2 %97 (96–98)#97 (95–98)-0.04 (-0.22–1.16)0.42
Minimum overnight Sa,O2 %86 (75.3–91.8)#91 (88.0–95.0)-2.0 (-11.25–0.75)0.12
Sa,O2 desaturation index events·h−11.2 (0.33–6.36)#0.9 (0.00–2.49)0.2 (-0.81–2.32)0.58
Mean overnight Ptc,CO2 kPa6.7 (6.1–7.0)#7.2 (6.7–7.7)-0.80 (-1.18– -0.42)<0.001*
Maximum overnight Ptc,CO2 kPa7.3±0.65#8.1±0.82-0.79(-1.14– -0.45)<0.001*
HRV HF ms2373±355309±33164 (-140–269)0.51
HRV LF ms21198 (639–2593)930 (505–2152)168 (-307–337)0.35
HRV VLF ms27790±50257217±5195574 (-1408–2555)0.55
TST h6.13 (5.40–6.75)6.22 (5.18–6.47)-0.02 (-0.63–0.45)0.86
Sleep latency h0.32±0.330.37±0.25-0.08 (-0.20–0.05)0.19
Sleep efficiency %74±13.077±9.9−2.68 (-8.29–2.94)0.33
Stage 1 sleep % TST19±10.416±9.03.49 (1.05–5.92)0.005*
Stage 2 sleep % TST42±8.841±8.01.25 (-2.48–4.98)0.49
Stage 3 and 4 sleep % TST25 (18.0–37.4)31 (22.4–41.7)-4.65 (-9.9– -1.4)0.11
Stage 3 and 4 sleep h1.60 (1.10–1.92)1.65 (1.18–2.30)-0.30 (-0.72– -0.02)0.08
REM sleep % TST12±6.412±5.4-0.65 (-3.47–2.18)0.64
Arousals98±70.382±62.116.0 (-7.00–39.00)0.16
Arousal index events·hour−121±9.418±9.43.5 (-0.17–7.22)0.06
Ventilator use+ h·day−17.9 (6.76–9.50)7.8 (6.48–9.27)0.2 (-0.16–0.66)0.16
Ventilator use days30±9.028±5.91.5 (-1.9–4.9)0.37
Ventilator use % days in study98 (95.7–100.0)100 (89.6–100.0)0.0 (-3.8–1.8)0.97
  • Data are expressed as mean±sd or median (interquartile range), unless otherwise stated. CI: confidence interval; Sa,O2: arterial oxygen saturation; Ptc,CO2: transcutaneous carbon dioxide tension; HF: high frequency; LF: low frequency; VLF: very low frequency; TST: total sleep time; REM: rapid eye movement. #: n = 19; : n = 16; +: of days used. *: p<0.05, considered significant.