Table 2

Imaging and physiological characteristics of two subgroups of rats ventilated with protective versus non-protective ventilation after HCl aspiration

Protective (n=35)Non-protective (n=38)
BaselineEndBaselineEnd
Body weight (g)355.7±46.2355.9±26.6
VT/BW (mL/kg)8.4±2.911.7±0.6*
PEEP (cmH2O)9.7±0.93.4±0.8*
HCl (mL/kg)3.1±0.72.5±0.8
Survivaln=35 (100%)n=22 (57.8%)
PaO2 (cmH2O)459.3±123.8403.2±135.9418.3±104.8205.0±172.8*†
Driving pressure (cmH2O)19.9±7.418.5±6.318.6±3.225.4±6.6*†
Compliance (mL/cmH2O)0.16±0.040.17±0.040.23±0.04*0.17±0.05†
High-risk tissue (%)15.8±11.018.2±14.3†49.9±13.3*55.8±14.3*†
Severe injury (%)8.9±5.617.4±13.5†11.4±3.820.7±9.7*†
Mechanical power (joule)0.117±0.0440.108±0.0370.110±0.0190.149±0.039†
  • Imaging, gas exchange and respiratory mechanics were measured at baseline (after HCl aspiration) and repeated at the end of the experiment. Tissue with severe injury and at high risk of injury progression was quantified using serial imaging analysis as described in the Methods section. PEEP and VT were constant throughout the experiment.

  • *p<0.01, between cohorts.

  • †p<0.01, vs baseline; all values are mean ± SD.

  • BW, body weight; HCl, hydrochloric acid; PEEP, positive end-expiratory pressure; VT, tidal volume.