Postoperative pneumoperitoneum after colorectal surgery: Expectant vs surgical management

Table 1 Pathophysiological mechanisms for some of the causes of nonsurgical pneumoperitoneum[2,4,19,20,22,23]

Nonsurgical causes	Pathophysiological mechanism
Pseudopneumoperitoneum	Adventitial air shadows
	Overdistension of hollow viscera
	Undulant configuration of the diaphragm
	Gas trapped in established wounds
	Basal pulmonary atelectasis
	Subdiaphragmatic extraperitoneal fat
	Interposition of the hepatic flexure of colon between right lobe of liver and diaphragm
Thoracic	Mechanical ventilation
	High airway pressures
	Large tidal volumes
	Noncompliant lungs
	Preexistant pulmonary disease
	Cardiopulmonary resuscitation
	Pneumothorax
	Pneumomediastinum
	Rapid decompression (diving accidents)
	Tracheal rupture
	Median sternotomy
	Blast injury
Abdominal	Postoperative retained air after abdominal surgery
	Peritoneal dialysis
	Percutaneous endoscopic gastrostomy
	Endoscopic procedures
	Pneumatosis cystoides intestinalis
	Blunt abdominal trauma
Gynecological	Vaginal insufflations
	Pelvic inflammatory disease
	Post partum knee chest exercises
	Coitus
	Gynecological exams
	Vaginal douching
Idiopathic