IS TENSION PNEUMOTHORAX A THREAT IN TRAUMA LAPAROSCOPY

Background: Tension pneumothorax is a reported risk with pneumoperiton eum in the presence of diaphragmatic injuries, A goat model with and w ithout diaphragmatic injury was used to determine if varying levels of intra-abdominal pressure (IAP) result in tension pneumothorax. Method s: Twenty-four goats were divided equally into four groups: (1)5 mm Hg IAP control, (2) 15 mm Hg IAP control, (3) 5 mm Hg IAP with diaphragm atic injury, (4) 15 mm Hg IAP with diaphragmatic injury. Chest x-ray f ilms were made and heart rate (HR), mean arterial pressure, central ve nous pressure (CVP), arterial blood gases, and airway pressure (AP) we re measured at 10-minute intervals up to 30 minutes, Significant chang es were determined by using the one-way analysis of variance and Mann- Whitney test with alpha set at p < 0.05. Results: In group 4, 100% tal l six goats) developed radiographic evidence of tension pneumothorax b y 10 minutes, Mean changes from baseline at 20 minutes for the followi ng parameters were all significantly different from controls: HR (p < 0.05), CVP (p < 0.0001), Pao(2) (p < 0.001), and AP (p < 0.004). Morta lity was 67% (four of six) at 25 minutes. In group 3, 100% (all six go ats) of the animals developed radiographic evidence of a simple pneumo thorax without mediastinal shift, In this group, there were significan t changes in Pao, (p < 0.003), AP (p < 0.04), and HR (p < 0.05), Morta lity was 16% tone of six) at 25 minutes. Conclusion: In this goat mode l of diaphragmatic injury, tension pneumothorax is a significant threa t when pneumoperitoneum is maintained at 15 mm Hg IAP, Pneumoperitoneu m at 5 mm Hg TAP leads to simple pneumothorax with deleterious effects on oxygenation. Changes in AP, CVP, HR, and Pao(2) provide early clue s to the development of the problem.