Fatal air embolism in diving. A morphologic study

Two cases of barotrauma as a result of excess pulmonary pressure with subsequent air embolism are reported. Both cases involved serious diving safety errors. The morphology of this type of barotrauma is described, with particular reference to the etiology of the phenomena involved. Some specific points regarding the autopsy procedure in connection with such diving accidents are discussed.     

Fatal paradoxical air embolism diagnosed by postmortem imaging and autopsy

The recognition and visualization of an arterial gas embolism are difficult. We report a case of sudden death caused by paradoxical air embolism of coronary and cerebral arteries, diagnosed by the pre autopsy computed tomography (CT) scanning. A 54-year-old woman suddenly died after the self-removal of the jugular vein catheter. Postmortem imaging examination using CT scanning showed multiple gas embolisms in the cerebral arteries, pulmonary artery, right atrium and ventricle, left ventricle, aorta, and coronary arteries. These findings suggested that the occurrence of acute ischemia of the brain and heart caused by massive air inflow to the artery. Conventional autopsy revealed a patent foramen ovale of the heart. These results indicated that the patient died of paradoxical air embolization of the coronary and cerebral arteries through a patent foramen ovale because of right-to-left shunting. The use of postmortem imaging as an aid for conventional autopsy has proved to be of advantage in the case of gas embolism.     

Pulmogenic air embolism

Interstitial emphysema and pulmonic hemorrhage alone are not the causes of pulmonic air embolism. The conditions making the entrance of air from the lungs to the vessels of pulmonary circulation are obviously present only if the expiration pressure is suddenly strongly elevated. Based on this point of view, investigations were performed in autopsy cases--falls from a height, being run over, a gunshot in the abdomen. We have succeeded in proving the entrance of air into capillaries and branches of the pulmonary vein. The precipitation of thrombocytes at the margin of large air bubbles in pulmonary veins shows the finding of air in the vessels as a vital or supravital reaction.     

静脉气体栓塞的研究进展

气体栓塞是一种较多见而又威胁生命的医疗操作并发症,在法医学实践中也时有所遇,但易被检验者所忽略;也常因尸体放置较久而给法医学检验和鉴定带来困难。在此综述了静脉气体栓塞的病因、病理生理变化、临床表现及诊断和法医学鉴定的意义及注意事项,认为超声心动图、CT和MRI等现代成像技术在气体栓塞的临床诊断和法医学鉴定中有积极的辅助作用。     

Fatal pulmonary cement embolism following percutaneous vertebroplasty (PVP)

A case of fatal pulmonary embolism with acrylic cement occuring during a percutaneous vertebroplasty on account of a fracture of L1 is described. Autopsy confirmed the presence of large amounts of surgical cement in the paravertebral venous system and in the pulmonary arteries. This rare complication occurred because perivertebral venous cement migration was not recognized during vertebroplasty. To our knowledge, this is the first case of fatal pulmonary embolism caused by surgical cement following a percutaneous vertebroplasty.     

Fatal embolism of the anterior spinal artery after local cervical analgetic infiltration

A 66-year-old man received a local infiltration of cortisone and xylocain in the left paravertebral region between the fifth and sixth cervical vertebrae. Respiratory failure occurred 2.5 h later with subsequent successful resuscitation. During the following 2 months of assisted ventilation up to the patients death, tetraplegia with concurrent full consciousness throughout was observed. Magnetic resonance imaging confirmed an ischaemic lesion of the upper anterior cervical myelon. The forensic autopsy revealed pneumonia as cause of death. Neuropathology confirmed anterior infarction at the C2/C3 level of the cervical myelon, with obstruction of the anterior spinal artery by an epithelialised fibrocartilaginous embolus. The autoptic findings suggest that this embolus stems from the site of previous analgetic infiltration, with accidental laceration of an intervertebral disc and subsequent transportation of discous material via injection canula into an artery.     

Fatal renal hemorrhage after extracorporeal shock wave lithotripsy

Renal hematoma is one of the most severe complications of extracorporeal shock wave lithotripsy (ESWL). ESWL is used in the noninvasive treatment of urinary calculosis. The shock waves can lead to capillary damage, renal parenchymal or subcapsular hemorrhage. We present a case with fatal complication and the result of the medico-legal evaluation. A 71-year-old woman was treated by ESWL, renal hematoma was detected during the clinical observation, and the patient died. The death occurred despite close clinical observation as a consequence of a rare complication of ESWL. The mechanism of death was hemorrhagic hypovolemic shock due to renal hemorrhage complications due to ESWL for treatment of renal calculi. This therapeutic complication is a known complication of appropriate treatment.     

Barotrauma and air embolism in hyperbaric oxygen therapy

A 69-year-old woman underwent hyperbaric oxygen therapy because of a nonhealing ulcer of her foot. During decompression, she developed a left-sided hemiplegia and confusion. Recompression resulted in transient neurologic improvement, but she eventually became comatose. Ventricular dysrhythmias developed and she died without regaining consciousness 17 h after onset of symptoms. An autopsy revealed diffuse interstitial pulmonary fibrosis with severe paracicatricial emphysema, chronic interstitial inflammation, and chronic bronchitis with abundant intrabronchial mucus. There was extensive multifocal ischemic injury of the cerebral cortex. The hippocampi, basal ganglia, and cerebellum were spared. Scattered acute myofiber necrosis was present in the heart. Clinical presentation and autopsy findings strongly support the diagnosis of air embolism and illustrate a potential risk of hyperbaric oxygen therapy in patients with preexisting pulmonary disease.     

Fatal accidents with compressed air diving equipment (author's transl)]

The post-mortem findings of 4 sport divers involved in accidents showed air embolism of the heart as well as 2 subcutaneous emphysemas of shoulder and neck. The lungs were distended and the viscera were hyperaemic. The pleura showed petechiae and small patchy hemorrhages. In microscopic examination foci of alveolar hemorrhages of the lungs and, occasionally, muscosal rupture of small branches of the bronchial tree and of the bronchioli could be determined. The most likely causes for the accidents are discussed and special attention is given to panicking under water.     

Infant death due to air embolism from peripheral venous infusion

An otherwise healthy male infant was brought to the hospital because the mother suspected superficial infection at the operative site 5 days after an inguinal hernia repair. He was admitted to the pediatric unit overnight to be evaluated by his surgeon the next morning. When a venous infusion of maintenance fluids was started, the patient immediately went into cardio-respiratory arrest and was pronounced dead after resuscitation efforts failed. Subsequently, air collections were found in both venous and arterial circulations, including the splenoportal system. Detailed review of the clinical presentation and course, laboratory results, radiological, and pathological findings, along with a review of pertinent literature provides an explanation for the death by air embolism. Apparent inconsistent findings both radiographically and at autopsy are resolved. The mechanism of distribution of air to both systemic and splenoportal circulation is discussed. We believe this to be only the eighth case reported in English-language literature of infantile death from peripheral venous infusion. In all age groups, we find only six other cases in the English-language literature of gas found concomitantly in both the systemic and portal venous systems.     

Fatal incidences during arrest of highly agitated persons

We report on four cases of sudden circulatory arrest during the physical restraint of extremely excited and repugnant men by the police. Three persons died, and one became apallic. The excited states resulted from acute schizophrenic disorder in one case, from intoxications (ethanol and drugs including cocaine respectively) in two others, and from encephalitis in the fourth case. In only one case one of the police officers was condemned for involuntary mansloughter, responsability was excluded in the remainder. Similar lethal events in "excited delirium" are given in the American literature, the main etiologic factors being acute psychosis and cocaine intoxication. Most of these events occurred, differing from ours, under "hogtying" which is a technique of physical restraint in a prone position with the wrists and ankles bound behind the back. These events are thought to be cardiac in origin and to result from oxygen-consuming motor hyperactivity, excessive catecholamine release, and impaired breathing. Police officers are recommended to restrict all measures of restraint to a mininum in extremely excited persons, and to avoid any compression of the trunk or neck. A continuous monitoring for vital signs is postulated in order to recognize a medical incident as quick as possible.     

Fatal anaphylactic shock during a fluorescein angiography.

The Authors describe an extremely rare fatal case (sixth case in the literature) of anaphylactic shock following a fluorescein angiography. This is the first report in which the diagnosis of anaphylactic reaction to the dye was made through laboratory analyses. The diagnosis of fatal shock due to sodium fluorescein was made based on clinical, laboratory and immunohistochemical data. Mast-cell tryptase was dosed in serum and a pulmonary immunohistochemical evaluation was performed. Tryptase, a neutral protease of human mast-cells is a potentially important indicator of mast-cell involvement in anaphylactic events.     

The potential of venous air embolism ascending retrograde to the brain

A bench study was performed to investigate the potential of air bubbles entering a central vein via a central venous catheter to ascend retrograde to the brain. The results support the hypothesis that air bubbles may rise retrograde against the venous blood flow, depending on bubble size, central vein diameter and cardiac output. A review of radiological findings in published case reports indicates that the occurrence of retrograde cerebral air embolism is underestimated.