the development of a pneumothorax during laparoscopic operations is an uncommon but potentially disastrous complication , frequently seen in elderly patients with cardiac and pulmonary compromise . other laparoscopic complications that must be distinguished from a pneumothorax include carbon dioxide embolism , acute reductions in venous return , vasovagal responses , tachyarrythmias , and pulmonary compromise . in most cases , a laparoscopic - induced pneumothorax ( or  carbo - thorax otherwise , the physiologic embarrassment of a pneumothorax is readily cleared with tube decompression in emergencies . the key to effective management is early recognition , and the authors herein describe the  floppy diaphragm  as a readily - observable and intraoperative clue to carbon dioxide above the diaphragm . in a personal series of 1900 laparoscopic cholecystectomies , three patients were found to have the  floppy diaphragm  sign . with desufflation of the abdomen , the diaphragm billowed inferiorly , thus reflecting the loss of negative pressure within the diaphragm . chest x - rays in the recovery area confirmed pneumothoraces which decreased in size about 50 percent within an hour . while laparoscopy was first performed in the 1890 's , the first case of spontaneous bilateral pneumothorax in association with pneumoperitoneum was reported in 1939 . in 1943 , most pneumothoraces are attributed to defects of the diaphragm , but other causes include trauma to the diaphragm during operations , rupture of emphysematous bullae , or the diffusion of co2 through anatomical pathways . the elderly , and those with cardiac and pulmonary abnormalities , seem most susceptible to a pneumothorax . complications include co2 embolism , decreased venous return , severe changes in heart rate , systemic vascular resistance , cardiac output , and pulmonary function . one possible mechanism of a pneumothorax is a leakage of co2 around the trocar sites into subcutaneous tissue . older patients have lax subcutaneous tissue , so that could be one reason why older patients are more susceptible to a pneumothorax . spontaneous pneumothoraces can result as co2 can pass through diaphragm openings along structures passing from the thoracic into the abdominal cavity , finding its way into the pleural cavity through the point of least resistance . a pneumothorax should be entertained if the patient has a fall in blood pressure , bradycardia , the pulse rate changes , tachycardia , surgical emphysema , or if ventilation is difficult . other signs that a patient might have a pneumothorax include a decrease in arterial oxygen saturation , an increase in airway pressures , and an increase in end - tidal co2 . this decrease in venous return is caused by an increase in arterial filling pressure combined with inferior vena cava pressure . when the diaphragm is elevated , the intraperitoneal pressure increases the intrathoracic pressure , which also impedes ventricular filling . most of the changes in cardiac output associated with a pneumothorax are due to increased abdominal pressure rather than the resorbed co2 and are reversible by desufflation . after surgery , there may be no obvious factor that caused the pneumothorax , and it may not even develop in the immediate postoperative periods . one case in the literature shows a pneumothorax occurring postoperatively as a result of vomiting . the surgical procedure should not always be assumed to be the cause of a pneumothorax . because of the potential complications associated with pneumoperitoneum , mechanical elevation of the abdominal wall has been evaluated . however , the view , and range of motion are inferior to conventional pneumoperitoneum . although a pneumothorax is very rare , the complications associated with it can be disastrous . in 1992 , prystowsky et al . twenty - one percent had a pneumothorax subsequent to laparoscopy , and the remainder had the pneumothorax after pneumoperitoneum for the treatment of intestinal or pulmonary tuberculosis . most pneumothoraces in association with laparoscopic procedures will resolve with desufflation of carbon dioxide from the abdominal cavity . however , an undetected pneumothorax during a laparoscopic procedure may cause cardiopulmonary instability . the most expeditious way to detect or confirm the presence of a pneumothorax is to inspect the diaphragm as carbon dioxide a pneumothorax may have occurred , and the patient should be monitored postoperatively to insure that the pneumothorax resolves on its own . tube thoracostomy may be appropriate if the pneumothorax is observed early in the operation or if hemodynamic instability does not respond to desufflation .
pneumothoraces in association with laparoscopy are uncommon and potentially disastrous complications that may also occur without adverse sequelae . 
 the  floppy diaphragm sign  is a readily discernible and useful sign of a laparoscopic - induced pneumothorax . 
 tube thoracostomy is generally not indicated in stable patients as the pneumothorax typically resolves quickly upon desufflation of the pneumoperitoneum .