INTRODUCTION: Abdominal compartment syndrome (ACS) is most often recognized in surgical and trauma intensive care units and in association with large volume of fluid resuscitation. This is a rare case of ACS due to pneumoperitoneum occurring in a medical intensive care unit (MICU) during high frequency oscillatory ventilation (HFOV).
CASE PRESENTATION: A 67-year-old male developed acute respiratory distress syndrome requiring mechanical ventilation after elective arthroscopic knee surgery at a local community hospital. Aspiration was suspected perioperatively. The patient was transferred to our MICU from the community hospital. He had a history of hypertension, diabetes, coronary artery disease and smoking. Pertinent findings on examination were an obese male and left lower lobe crackles. Otherwise physical examination was unremarkable with no signs of congestive heart failure. PaO2/FiO2 ratio was 80. Chest radiography and computed tomography showed bilateral diffuse opacities. There was no pulmonary embolism. Due to persistent hypoxia despite diuretics, antibiotics and conventional modes of mechanical ventilation, HFOV was initiated. On day 5 of HFOV, the patient developed acute hypoxia and hypotension requiring vasopressors. Oliguria was also noted. Central venous pressure (CVP) was 18. Hypotension and oliguria were resistant to fluid resuscitation. Examination revealed BP 69/34 mm Hg. HFOV settings: amplitude 86 cm H2O, frequency 3 Hertz, mean airway pressure 45 cm H2O, FiO2 93%. Crepitus was noted on upper chest. Abdomen was distended, tympanic to percussion. Immediate chest radiograph revealed extensive subcutaneous emphysema and pneumomediastinum but no pneumothorax. Over the next 6 hours, due to increasing abdominal girth, a cross table lateral film was done that revealed free air in the abdomen suggestive of pneumoperiotoneum. Because of abdominal distension and concern for abdominal compartment syndrome, urinary bladder (UB) pressure was measured and was elevated at 43 mm Hg. Surgery team performed a bedside diagnostic peritoneal lavage. As soon as the peritoneum was entered, gush of air was released with no blood, bile or stool. After abdominal decompression, UB pressure decreased to 14 mm Hg and BP and urine output normalized.
DISCUSSIONS: The patient had ACS causing hypotension and oliguria due to large amount of free air in the peritoneum (pneumoperitoneum) as a result of barotrauma from HFOV. Barotrauma caused pneumomediastinum and subcutaneous emphysema with subsequent leakage of air into the peritoneal cavity. Intraabdominal pressure as detected by UB pressure above 20 mm Hg along with at least one new organ failure (both hypotension and oliguria in this patient) is highly suggestive of ACS. Hypotension was a result of direct compression of inferior vena cava from elevated abdominal pressure and decreased cardiac output from high intra-thoracic pressures. Oliguria was due to abdominal pressure causing reduction in the renal filtration gradient. Both hypotension and oliguria completely resolved with abdominal decompression. CVP is often falsely elevated both in ACS and with HFOV and must be interpreted with caution. High index of suspicion and early detection is key to diagnosing ACS which if unrecognized has a very high mortality.
CONCLUSION: ACS is increasingly recognized in the medical intensive care unit. This is an unusual case of pneumoperitoneum from HFOV barotrauma causing ACS. After a long hospital course, this patient developed multiorgan failure and died.
DISCLOSURE: Sucharita Kher, No Financial Disclosure Information; No Product/Research Disclosure Information