Effects of stomach inflation on haemodynamic and pulmonary function during spontaneous circulation in pigs.

ABSTRACT

AIM: Stomach inflation during mask ventilation is frequent, but the effects on haemodynamic and pulmonary function are unclear. We evaluated the effects of stomach inflation on haemodynamic and pulmonary function during spontaneous circulation in a porcine model. METHODS: Randomised prospective animal study. After randomisation, in 23 domestic pigs the stomach was inflated every 90s with 0L (control; n=8), 0.5L (n=7) or 1L (n=8) ambient air. RESULTS: After 22.5min, i.e. 8.5L in the 0.5L and 17L in the 1L stomach inflation group, stomach inflation increased central venous pressure (median) (control 10mmHg vs. 1L 23mmHg, P<0.05) and mean pulmonary artery pressure (control 24mmHg vs. 1L 45mmHg, P<0.05). As a result stroke volume index decreased (control 135mL/kg vs. 0.5L 90mL/kg, P<0.05; vs. 1L 72mL/kg, P<0.05). Stomach inflation also decreased static pulmonary compliance (control 24mL/cmH(2)O vs. 0.5L 8mL/cmH(2)O, P<0.05; vs. 1L 3mL/cmH(2)O, P<0.05), which increased peak airway pressure (control 28cmH(2)O vs. 0.5L 69cmH(2)O, P<0.05; vs. 1L 73cmH(2)O, P<0.05). Additionally, arterial oxygen partial pressure (control 305mmHg vs. 0.5L 140mmHg, P<0.05; vs. 1L 21mmHg, P<0.05) and systemic oxygen delivery (control 53mLO(2)/min vs. 1L 19mLO(2)/min, P<0.05) decreased. Stomach inflation increased mortality (control 0/8 vs. 1L 5/8, P<0.05). CONCLUSIONS: Stomach inflation with 1L when compared to 0.5L increments resulted in faster haemodynamic and pulmonary failure and increased mortality. Stomach inflation may cause a hyper-acute abdominal compartment syndrome.