title: Alternating ventilation in a rat model of increased abdominal pressure.
abstract: During alternating ventilation (AV) one lung is inflating while the other is deflating. Considering the possible respiratory and hemodynamic advantages of AV, we investigated its effects during increased intra-abdominal pressure (IAP=10 mmHg). In Sprague-Dawley rats (n=6, 270-375g) the main bronchi were independently cannulated, and respiratory mechanics determined while animals underwent different ventilatory patterns: synchronic ventilation without increased IAP (SV-0), elevated IAP during SV (SV-10), and AV with elevated IAP (AV-10). Thirty-three other animals (SV-0, n=10; SV-10, n=11 and AV-10, n=12) were ventilated during 3h. Mean arterial pressure (MAP), and lung histology were assessed. Increased IAP resulted in significantly higher elastances (p<0.001), being AV-10 lower than SV-10 (p<0.020). SV-10 showed higher central venous pressure (p<0.003) than S-0; no change was observed in AV-10. Wet/dry lung weight ratio was lower in AV-10 than SV-10 (p=0.009). Application of AV reduced hemodynamic and lung impairments induced by increased IAP during SV.
authors.affiliation: Laboratory of Respiratory Physiology, Carlos Chagas Filho Biophysics Institute, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil. vicarc@gmail.com
authors.forename: Viviane Ramos
authors.initials: VR
authors.lastname: Cagido
authors.forename: Walter Araújo
authors.initials: WA
authors.lastname: Zin
authors.forename: José
authors.initials: J
authors.lastname: Ramirez
authors.forename: Daniel
authors.initials: D
authors.lastname: Navajas
authors.forename: Ramón
authors.initials: R
authors.lastname: Farré
mesh_terms: D000005:Abdomen / Q000502:physiology; D000818:Animals; D004195:Disease Models, Animal; D006439:Hemodynamics / Q000502:physiology*; D006973:Hypertension / Q000473:pathology / Q000503:physiopathology*; D008168:Lung / Q000473:pathology / Q000502:physiology; D008297:Male; D011312:Pressure; D012123:Pulmonary Ventilation / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D015656:Respiratory Mechanics / Q000502:physiology*