Related Experiment Video
Updated: May 23, 2026
Ex Vivo Porcine Experimental Model for Studying and Teaching Lung Mechanics
Published on: April 19, 2024
Haemodynamic stability and pulmonary shunt during spontaneous breathing and mechanical ventilation in porcine lung
L Vimláti1, A Larsson, G Hedenstierna
1Department of Surgical Sciences, Anaesthesiology and Critical Care Medicine, Uppsala University, Uppsala, Sweden. laszlo.vimlati@surgsci.uu.se
Background:
We investigated the haemodynamic stability of a novel porcine model of lung collapse induced by negative pressure application (NPA). A secondary aim was to study whether pulmonary shunt correlates with cardiac output (CO).
Methods:
In 12 anaesthetized and relaxed supine piglets, lung collapse was induced by NPA (-50 kPa). Six animals resumed spontaneous breathing (SB) after 15 min; the other six animals were kept on mechanical ventilation (MV) at respiratory rate and tidal volume (V(T) ) that corresponded to SB. All animals were followed for 135 min with blood gas analysis and detailed haemodynamic monitoring.
Results:
Haemodynamics and gas exchange were stable in both groups during the experiment with arterial oxygen tension (PaO(2) )/inspired fraction of oxygen (FiO(2) ) and pulmonary artery occlusion pressure being higher, venous admixture (Q(va) /Q(t) ) and pulmonary perfusion pressure being lower in the SB group. CO was similar in both groups, showing slight decrease over time in the SB group. During MV, Q(va) /Q(t) increased with CO (slope: 4.3 %min/l; P < 0.001), but not so during SB (slope: 0.55 %min/l; P = 0.16).
Conclusions:
This porcine lung collapse model is reasonably stable in terms of haemodynamics for at least 2 h irrespective of the mode of ventilation. SB achieves higher PaO(2) /FiO(2) and lower Q(va) /Q(t) compared with MV. During SB, Q(va) /Q(t) seems to be less, if at all, affected by CO compared with MV.
