The cardiorespiratory effects of increased intra-abdominal pressure in diaphragmatic rupture.

The cardiorespiratory effect of gastric herniation in diaphragmatic rupture with and without increased intra-abdominal pressure (produced by inflation of a pneumatic antishock garment [PASG] to an intraperitoneal pressure of 40 mm Hg) was studied in 16 anesthetized spontaneously breathing (80% oxygen) piglets. Four additional animals had similar measurements after PASG inflation but without diaphragmatic rupture. Arterial blood pressure (BP), cardiac output, arterial blood gases, position of the stomach relative to the diaphragm (as measured on fluoroscopy), and mortality were assessed. Gastric herniation without the PASG (group I: 8 animals) produced slight cardiorespiratory deterioration, with PO2 falling from a baseline measurement of 429 +/- 60 mm Hg to 316 +/- 5 mm Hg at 1 hour. Over this period pH decreased from 7.39 +/- 0.05 to 7.30 +/- 0.02 and PCO2 increased from 39 +/- 5 to 46 +/- 2 mm Hg. With PASG inflation (group II: 8 animals) PO2 decreased to a greater extent, from 410 +/- 30 mm Hg at baseline to 48 +/- 10 mm Hg by 1 hour; pH decreased from 7.38 +/- 0.06 to 6.8 +/- 0.2 and PCO2 increased from 39 +/- 4 to 88 +/- 6 mm Hg. Animals without diaphragmatic rupture (group III: 4 animals) showed a smaller decrease in PO2, from 480 +/- 34 mm Hg at baseline to 320 +/- 50 mm Hg by 1 hour after PASG inflation.(ABSTRACT TRUNCATED AT 250 WORDS)