Table 2—

Effects of different pressurization rates (PR) at 5 cmH2O of pressure support ventilation (PSV)

CharacteristicPR
LowestLowBaselineHighHighest
RR bpm32±13#30±1230±1029±932±10
VT mL272±91¶,##342±88##334±104##376±99¶,##334±74##
V'e L·min−17.9±2.09.7±2.89.5±2.810.5±2.410.4±2.7
ti, s1.0±0.40.9±0.30.8±0.30.9±0.30.9±0.2
ti/ttot0.47±0.080.42±0.050.40±0.050.40±0.050.42±0.05
tPSV s1.0±0.40.9±0.30.4±0.20.2±0.090.1±0.1+
PIF mL·s−1473±141¶,##602±194##660±168##685±204##758±302#,##
Dyspnoea cm2.7±1.1§ (1–4)1.6±1 (1–3)1.2±0.4 (1–2)1.5±1 (0–3)2.4±1.5f (0.5–5)
PTP cmH2O s·min−1340±150¶,## (139–522)220±122## (51–379)141±76## (45–221)159±87## (25–291)180±84## (46–314)
WOB·min−1 J·min−113.0±7.9¶,## (4.4–24)11.3±7.8## (2–17.4)7.6±5.5## (0.9–15.8)8.9±6.2## (1–20.4)10.4±7.7## (1.6–28.7)
WOB·L−1 J·L−11.53±0.6¶,## (0.8–2.6)1.04±0.5## (0.4–1.7)0.71±0.4## (0.3–1.3)0.77±0.4## (0.4–1.4)0.93±0.5## (0.2–2.0)
PEEPi cmH2O1.4±1.11.6±1.41.3±0.81.4±0.91.6±0.9
P0.1 cmH2O3.7±2.62.5±1.62.1±1.31.8±1.12.4±1.6
  • Data are presented as mean±sd (range)

  • RR: respiratory rate; bpm: breaths·min−1

  • Vt: tidol volume

  • V'e: minute ventilation

  • ti: inspiratory time

  • ti/ttot: duty cycle

  • tPSV: time to reach pressure support level

  • PIF: peak inspiratory flow

  • dyspnoea: Borg's dyspnoea scale

  • PTP: pressure time product

  • WOB·min−1: work of breathing per minute

  • WOB·L−1 work of breathing per L of ventilation

  • PEEPi: dynamic intrinsic positive end-expiratory pressure

  • P0.1: mouth occluded airway pressure at 0.1 s

  • All p-value are <0.05 for the following:

  • #: versus low PR

  • : versus low, baseline, high, highest PR

  • +: versus baseline

  • §: versus low, baseline, high PR

  • f: versus low, baseline PR

  • ##: versus PSV 15