Systemic air embolism: does it occur after experimental penetrating lung injury?

Systemic arterial air embolization following penetrating injury of the lung has been previously reported. As we had not recognized this complication clinically, we studied this problem in 11 healthy dogs. In each of them, a mock circulation was created by establishing two central external arteriovenous shunts with transparent plastic tubing in which air bubbles could be seen. Also, a Doppler flow detector capable of sensing intravascular air was attached to a carotid artery. Systemic arterial and pulmonary capillary wedge pressures were recorded, and a standard lung laceration was produced. In 5 of the dogs, in addition, tension pneumothorax was induced by injection of air into the pleural space. The dogs were monitored for intravascular air for 15 minutes before and after the induction of hypotension by withdrawal of blood from the shunts. In no animal was air seen in the shunts, nor was there the characteristic deflection of the Doppler seen with intravascular air, although the preparation was sensitive to the detection of as little as 1 ml. of air injected into the left atrium. These observations lead us to question whether arterial air embolism occurs with penetrating pulmonary trauma in man.

Value of perfusion lung scans in selection of patients for vena cava interruption.

Sixty-seven patients with pulmonary embolic disease (diagnosed clinically and with perfusion lung scans) were studied. In 48 of them, the scans were interpreted as positive for pulmonary emboli and in 19, as questionable. All 67 patients underwent pulmonary arteriography. The pulmonary arteriogram showed no evidence of pulmonary embolus in 11 of the 48 patients with positive findings on lung scan and no evidence in 12 of the 19 patients with questionable lung scan. Because of the high false-positive rate of the perfusion lung scan, we strongly recommend angiographic confirmation of pulmonary embolism when interruption of inferior vena cava is contemplated for the prevention of recurrence of pulmonary embolism.

Penetrating cardiac wounds: A comparison of different therapeutic methods.

The management of penetrating wounds of the heart has been controversial. During the last 10 years we have used 3 different therapeutic approaches for the treatment of these wounds and the obtained results comprise this report. From 1964 to 1974 we treated 102 patients, four of whom expired immediately after their arrival to the clinic. The remaining 98 patients were divided into five groups according to their clinical presentation and treatment. Group I, 17 patients (14 with stab and 3 with bullet wound) seen with cardiac tamponade from 1964 to 1967 were treated first with pericardiocentesis and then were operated upon if pericardiocentesis yielded no results or if cardiac tamponade recurred. Fourteen patients recovered and three died, with an overall mortality of 17.5% Group II, 34 patients (23 with stab and 11 with bullet wound) were seen with cardiac tamponade from 1968 to 1971. The patients with stab wound were managed the same as group I patients and those with bullet wound were operated upon immediately. Twenty-nine recovered and 5 died, with an overall mortality of 14.7%. Group III, 20 patients (12 with stab and 8 with bullet wound) were seen with cardiac tamponade from 1972 to 1974. All of them were operated upon immediately and pericardiocentesis was used in this group only to provide time for a safe operation. Nineteen recovered and one died, with an overall mortality of 5%. Group IV, 20 patients (5 with stab and 15 with bullet wound) with massive bleeding, were operated upon immediately. Ten (4 out of the 5 with stab and 6 out of the 15 with bullet wound) recovered, with a mortality rate of 50%. Group V, seven patients were seen throughout the study period without bleeding or cardiac tamponade. Some of them were operated upon electively and others are being followed and all have done well. This study suggests (1) that patients with penetrating wound of the heart and cardiac tamponade or bleeding will derive better results if they are operated upon as soon as possible and if pericardiocentesis is used to provide time for a safe operation and (2) that those with other manifestations should be evaluated and if their lesion is significant, they should be operated upon electively.