Table 2

Difference between consecutive recordings of measured physiological variables in 30 patients from day of baseline measurement to repeat reading

∆MEWS*∆RR∆SpO2∆FEV1∆EMGpara∆EMGpara%max∆NRDI
‘Deteriorators’0.50 (0–1)4.5±6.01.2±2.40.03±0.187.8±4.96.2±4.3226±58
‘Improvers’0 (−2–1)−1.8±3.80.9±2.70.06±0.14−1.7±5.5−3.5±8.1−113±221
Mean difference (95% CI)6.3 (−0.1 to 12.6)−0.6 (−2.0 to 3.1)0.03 (−0.42 to 0.36)9.6 (4.4 to 14.8)9.6 (4.5 to 14.8)339 (234 to 444)
p Value0.020.050.60.70.0030.001<0.001
  • Data presented as mean±SD or *median (range).

  • Seven patients were unable to perform spirometry on one or more occasions so analysis of FEV1 was performed on ‘improvers’ (n=20) and ‘deteriorators’ (n=3).

  • EMGpara%max, EMGpara during tidal breathing normalised for maximum EMGpara produced during a sniff manoeuvre; RR, respiratory rate; NRDI, neural respiratory drive index (RR × EMGpara%max); EMGpara, parasternal electromyogram activity; FEV1, forced expiratory volume in 1 s; MEWS, medical early warning score.