Pneumoperitoneum. A complication of mechanical ventilation

Spontaneous pneumoperitoneum after pneumonia in a child

Pneumoperitoneum is considered to be a surgical emergency as it nearly always indicates a perforated abdominal viscus. However, in rare cases, the presence of 'free gas under diaphragm' may not imply the need for emergent laparotomy, as pneumoperitoneum can occur without any gastrointestinal leakage. Here we report a rare case of a previously healthy boy with pneumoperitoneum associated with pneumonia and perform a review of the literature to explore the etiological mechanisms and the pathophysiology of non-surgical pneumoperitoneum.

Pneumomediastinum causing pneumoperitoneum during mechanical ventilation

The causes of nonsurgical pneumoperitoneum include numerous diseases. We report here a case of nonsurgical pneumoperitoneum caused by benign pneumomediastinum during mechanical ventilation, and we discuss the anatomic pathways and the pathophysiologic mechanisms responsible for the development of this association.

Pneumoperitoneum complicating mechanical ventilation in congenital myotonic dystrophy

Pneumoperitoneum is known as a disease caused by perforation of the gastrointestinal tract, but it has also been reported as a complication of mechanical ventilation. In a case of congenital myotonic dystrophy (CMyD), mechanical ventilation was performed to treat severe respiratory distress starting at birth, and then pneumomediastinum and pneumoperitoneum developed as complications 5 days after birth. The fact that the pneumoperitoneum improved when the ventilation pressure was reduced and the patient's course was observed, allowed us to rule out gastrointestinal perforation. It appeared that hypoplasia of the diaphragm may have been involved in the progression of pneumomediastinum to pneumoperitoneum in this patient. Mechanical ventilation is performed on many occasions in CMyD, and the development of pneumoperitoneum secondary to pulmonary air leak should always be borne in mind.

A review of computerized tomography in blunt abdominal trauma at Christchurch Hospital

A review was undertaken of computerized tomography (CT) of the abdomen, performed between March 1993 and December 1994 for blunt abdominal trauma at Christchurch Hospital. CT findings were correlated with the clinical outcome. The outcome was either recovery from an abdominal point of view with or without laparotomy, or postmortem. A total of 116 CTs were reviewed, of which 76 were abnormal. CT was highly sensitive and specific for a variety of abdominal traumatic lesions. There were 1 false positive and 4 false negatives (only 2 of these significant). There was 1 non-therapeutic laparotomy based on CT findings. There was only 1 case of delayed treatment based on CT results. Three patients had unexplained findings of pneumoperitoneum. Care should be taken when interpreting the presence of free intraperitoneal air on CT scan. The possibility of missed bowel perforation should be considered, especially in the presence of free intra-abdominal fluid and no solid organ injury to account for it. CT scans are useful in the conservative management of solid organ injuries.

Pneumoperitoneum associated with artificial ventilation

Four adults injured in serious road-traffic accidents developed pneumoperitoneum after artificial ventilation. No case could be attributed to injury or to perforation of a hollow viscus in the belly, but doubt about this in one patient resulted in exploratory laparotomy. In three patients the origin of intraperitoneal air was considered to be leakage through minute ruptures in alveoli subjected to the stress of artificial ventilation, with air tracking to the mediastinum, pleural space, subcutaneous tissues of the neck and chest, and peritoneal cavity. The fourth patient later developed herniation of the stomach through a rupture in the diaphragm, the presence of a pneumothorax on the same side suggesting direct passage of air through the diaphragm. Pneumoperitoneum induced by artificial ventilation is probably more common than reports suggest and should be distinguished clinically and radiologically from that caused by rupture or perforation of a hollow viscus. This will reduce the number of needles laparotomies performed on patients who are already seriously ill.

Postoperative pneumoperitoneum: an unusual etiology

Although postoperative pneumoperitoneum is a common finding, it is particularly disturbing when there is an increase in the amount of postoperative pneumoperitoneum or when the radiographic finding of pneumoperitoneum is accompanied by such physical findings as increased abdominal tenderness, peritoneal signs or paralytic ileus. Four patients operated upon at the Mount Sinai Hospital are presented. All patients underwent abdominal surgery for treatment of some form of inflammatory bowel disease and all were receiving systemic corticosteroids in the postoperative period. Abdominal findings of tenderness, ileus and peritoneal irritation developed shortly after the removal of Penrose drains in the postoperative period. Pneumoperitoneum was confirmed by abdominal roentgenographs. The first patient in this group underwent a laparotomy with essentially negative findings other than a freely open drain tract. The subsequent three patients were managed by close observation and frequent abdominal radiographs. These three patients had contrast roentgenographic studies of the upper gastrointestinal tract to rule out perforation of a peptic ulcer, and in the patient upon whom reservoir ileostomy had been performed, a contrast study of the reservoir was performed. All patients recovered fully with this management and there were no sequelae. The mechanism for the appearance of pneumoperitoneum after removal of drains, particularly when the patient is receiving systemic corticosteroids, is discussed. Emphasis is placed on the need to consider and rule out perforation of a hollow viscus in this situation before accepting drain removal as the sole cause of post-operative pneumoperitoneum.