To the Editor:—

In the case report by Ibrahim et al. , 1in which a 64-kg man developed tension pneumothorax and systemic air embolism during positive pressure ventilation with a rather large tidal volume of 1,000 ml, there seems to have been unnecessary delay before a chest tube relieved the left-sided pneumothorax with immediate improvements in hemodynamic parameters. The exact time between the circulatory collapse and the chest tube placement that relived the tension pneumothorax is not clear. But there seems to have been enough time to perform, along with routine resuscitation, a transesophageal echocardiographic study of the cardiac chambers and a fiberoptic study and manipulation of the airway before the pneumothorax was relieved by chest tubes.

The patients abdomen was open for pancreatic debridement at the time of circulatory collapse. Under these circumstances, the tension pneumothorax can be diagnosed/ruled out by examination of the diaphragm by the operating surgeons. If the diaphragm is tense and bulging down into the abdomen, the tension pneumothorax can initially be relieved via  an opening through the diaphragm followed by a formal chest tube placement on the same side. This approach not only avoids unnecessary delay in the definite therapy for pneumothorax, but also eliminates the need for bilateral chest tubes in unilateral pneumothorax. We have personal experience in managing intraoperative spontaneous tension pneumothorax using the diaphragm sign during laparotomy on a patient with cystic fibrosis (unpublished data, September 1995). When pneumothorax occurs during laparoscopic procedures, the status of the diaphragm may be visualized using the laparoscope. 2 

Ibrahim AE, Stanwood PL, Freund PR: Pneumothorax and systemic air embolism during positive-pressure ventilation. A NESTHESIOLOGY 1999; 90:1479–81
Voyles CR, Madden B: The “floppy diaphragm” sign with laparoscopic associated pneumothorax. J Soc Laparoendosc Surg 1998; 2:71–3