Retrograde venous cerebral air embolism from disconnected central venous catheter: an experimental model

There are few reported cases of death attributed to retrograde cerebral air embolism from central venous catheter. The pathophysiological mechanism and the necessary conditions are not fully understood, also because of missing experimental data. We performed experimental simulation while working on a possible case of retrograde cerebral air embolism. A hermetic system consisting of two containers connected to each other and to an electric pump by means of rubber hoses was built. In this system, a fluid (water and blood) could continuously flow under conditions similar to those of the common jugular vein. The part of the system representing the jugular vein could be freely positioned at angles between 0 and 90°. A central venous catheter was inserted into this part. After disconnection, the behavior of the air bubbles entering the hose through the tip of the catheter was evaluated at different positions. At angles between 0 and 45°, the air bubbles followed the fluid flow. At angles >45°, the air bubbles showed the tendency to flow upstream; this phenomenon was more evident the more vertically the hose was located. We were able to demonstrate that a retrograde air embolism can be caused by a disconnected catheter and is even more likely if the neck is in a vertical position.     

Significance of anastomoses in the lung in microembolism

The importance is demonstrated of anastomoses between the pulmonary artery and the bronchial artery as well as of the arteriovenous anastomoses that arise from these in microembolism. In cases of air embolism, microembolism in the lungs is seldom. Therefore, there must be particular circumstances that make it possible for little air bubbles to pass the anastomoses from the pulmonary artery via the bronchial artery and the arteriovenous anastomoses into the bronchial vein. The pressure in the bronchial artery must decrease. Under these conditions, blood is shunted from the pulmonary artery to the bronchial artery and little air bubbles can pass via the above-mentioned anastomoses into the pulmonary vein.     

Suicide by Intentional Air embolism

Venous air embolism occurs when air enters the venous system. The main causes of venous air embolism include medical procedures, neck and head trauma, and injuries of the genitals. Self‐induced suicidal (and intentional) air embolism is extremely rare. The authors report a rare case of a suicidal air embolism committed using a self‐made tool composed of a plastic bottle and an infusion set, injecting nearly 2000 mL of air into the cubital vein. The toxicological analysis suggested that midazolam, together with air, was also injected into the circulation using the same bottle and infusion set.     

Retrograde transthoracic venous bullet embolism. Report of a case following a single gunshot with multiple wounds in the left arm and chest

Bullet embolism of the arterial, venous and paradoxical types are well known but rare complications of penetrating missile injuries. Retrograde transthoracic venous bullet embolization is extremely rare with only four cases previously reported in the literature. Single gunshot can cause multiple wounds, mainly because the bullet passes through an intermediate target before striking the victim. We present the autopsy findings of a retrograde transthoracic bullet embolism to the right external iliac vein after a single gunshot with multiple wounds in the left arm and thorax. Problems related to medico-legal investigations of gunshots are reviewed.     

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.     

Air embolism following arthroscopy--autopsy findings and forensic medicine aspects

An iatrogenic cause of air embolism with a fatal outcome is reported that occurred in a case in which arthroscopy of the knee had been carried out. Even after worldwide use of arthroscopy for many years, this complication has never been seen until now. At autopsy, when air bubbles were observed in the right heart chamber and in the vena cava inferior, only the knee joint was taken into consideration as the air-access route. The access of air was detected by means of arthroscopy on the corpse, combined with a special autopsy technique and shown experimentally. Insufflated air had entered via a fracture of the tibial articular surface and then passed through the spongiosa into the femoral vein. These findings are of far-reaching clinical consequence because the indication for arthroscopy by gas insufflation must be reconsidered again. Finally, the medicolegal aspects of such an incident are discussed.     

A statistical study of air bubbles on athletic shoesoles

Comparisons of a shoemark with a shoesole (and standards) sometimes lead to associations based on air bubbles (among other manufacturing or acquired characteristics). Today, the assessment of the evidential value of air bubbles coincidences relies largely upon the examiner's experience and/or follows sometimes a verification based on the examination of a small number of analogous pairs collected for the case at hand. Statistical data related to the occurrence and characteristics of air bubbles on shoesoles in an attempt to model the potential variability have been gathered. Seventy-one pairs of shoes with the same design, brand, model and size were obtained. Right and left soles were photographed. An image-processing algorithm was developed to allow the systematic acquisition of data such as: (1) the number of air bubbles on the sole and around given structural elements; (2) the measure of air bubbles characteristics such as their surface and position. These data allow a discussion of the assessment of the probability of finding on shoesoles (same design, brand, model and size) a certain number of air bubbles on a surface with the same positions and morphology.     

Gas embolism as a cause of death

Systemic venous gas embolism other than that due to air is a great rarity. A case is reported and the criteria for the diagnosis are discussed. The clinical similarities between embolism of systemic venous air and that of systemic venous gas are emphasized. The two conditions can be differentiated by laboratory investigation only.     

Venous air embolism in homicidal blunt impact head trauma. Case reports

From 1992 through 1997, there were 41 deaths by homicidal blunt impact head trauma in Hillsborough County, Florida. Twenty-one cases were excluded from the study because of putrefaction or survival beyond the emergency department doors, leaving 20 cases for the study. One of the 15 nonputrefied victims found dead at the scene and 1 of the 5 victims pronounced dead in the emergency department had definite venous air embolism. Victim 1 was found dead, bludgeoned with a concrete block, and had open vault and comminuted basilar skull fractures. The dura forming the right sigmoid sinus at the jugular foramen was lacerated. A preautopsy chest radiograph and examination under water documented gas in the pulmonary artery and right ventricle. Victim 2 was bludgeoned with a steel stake and was pronounced dead on arrival in the emergency department. He had open comminuted vault fractures, a transverse basilar skull fracture, and lacerations of the brain. Direct examination and preautopsy chest radiography revealed air in the right side of the heart. A third victim, with basilar fractures, had a small gas bubble in the pulmonary artery not detected by the case pathologist. A fourth victim, with a basilar skull fracture, had an unusual radiographic finding that was thought to be air in the posteromedial aspect of the lower lobe of the left lung but could not be excluded as an air embolus. Optimal postmortem documentation of venous air embolism includes the demonstration of the embolus and the site of air ingress. This study demonstrates that venous air embolism occurs in some victims of homicidal bludgeoning and suggests that when significant, it is easily demonstrated in the absence of putrefactive gas formation. The presence of venous air embolism can serve as evidence that a victim was alive and breathing at the time of the infliction of head wounds. In the belief that venous air embolism might be underdiagnosed in many medical examiner offices, the authors have sought to bring attention to the entity by publishing their experience with it in cases of bludgeoning.     

A Case of Fatal Spontaneous Varicose Vein Rupture—An Example of Incorrect First Aid

Abstract:  Severe external bleeding due to varicose vein rupture is a rare complication of this frequent venous pathology. Venous bleeding can be very intensive and can be mistaken for arterial hemorrhage. A rare case of fatal varicose vein rupture with an example of an incorrect and ineffective first-aid technique in a 43-year-old man is reported here with a review of the recent literature. The victim was found on a sand stack, not far from his domicile in a large pool of blood. The external examination revealed a flat ulcer on the internal surface of the right shank. On dissection, the lesion contained a perforation that was continuous with superficial veins arising from a varicosed saphenous vein. The man tried to give himself first aid, due to the massive bleeding that he probably predicted arterial bleeding and applied the ligature closer to the heart above the bleeding defect, thereby not stopping the venous bleeding but exacerbating it. Death was caused by a hypovolemic shock because of external hemorrhage from a varicose vein.     

Correlation of antemortem and postmortem digoxin levels.

Postmortem serum digoxin levels from any source routinely exceed antemortem values. Variation resulting from site of sampling gave a mean postmortem to antemortem ratio of 1.96 for heart, 1.63 for subclavian vein, and 1.42 for femoral vein samples. No correlation could be made between the postmortem interval and the increase in post-mortem serum values, irrespective of the site of sampling. A combination of femoral venous serum and vitreous humor values gave the best information for determining possible antemortem digoxin toxicity.     

Iatrogenic catheter-related cardiac tamponade: a case report of fatal hydropericardium following subcutaneous implantation of a chemotherapeutic injection port

The need to obtain dependable access to the vascular system constitutes a significant component in the treatment and management of critically ill patients. Intravenous chemotherapy administered to cancer patients over an extended period of time often results in loss of peripheral vascular access due to vein sclerosis, "exhaustion" or tissue necrosis. Medical investigators have designed and steadily upgraded a variety of devices constructed to improve venous access for long-term utilization. As with the introduction of any foreign object into the body, each of these devices has complications which may be life threatening and occasionally fatal. We present an unusual case of iatrogenic acute hydropericardium and cardiac tamponade caused by the percutaneous infusion of chemotherapeutic fluid via a right subclavian central venous implant system (Port-a-Cath). Failure to implant and monitor the device with a radiograph following placement according to manufacturer's guidelines and accepted standards of medical practice were causally related to an unusual complication, namely, perforation of the right cardiac ventricle by the catheter tip, resulting in sudden and unexpected cardiac death.     

Bloodstain pattern analysis in a case of fatal varicose vein rupture

Rupture of a varicose vein is a rare cause of sudden death. It occurs when the failure of venous valves causes an increase in venous pressure great enough to provoke rupture of the blood vessel. When it does happen, the victim is often found surrounded by a pool of blood, and the examination of the scene can mislead the forensic team to think of violent death. Until now, the bloodstain patterns in these fatal cases have not been described. An examination of the bloodstain pattern in a case of fatal varicose vein rupture in an 84-year-old man is here reported.     

兔静脉空气栓塞死后不同间隔时间气体变化的初步研究

目的探讨兔静脉空气栓塞死后不同间隔时间气体变化的规律,为空气栓塞致死的法医学鉴定提供参考资料。方法建立兔静脉空气栓塞动物模型,按死后不同间隔时间分为0h、12h、1d、2d、4d、8d和16d共7组,分别从右心检测气体体积及其中CH4、CO2和N2体积百分比浓度。结果实验组均收集到气体,阴性对照组除了16d组收集到0.95ml外,均未收集到气体（V〈0.1ml）。实验组中,0h、12h和8d3组间所收集气体的差异无统计学意义（P〉0.05）,1d和2d两组之间右心气体体积的差异无统计学意义（P〉0.05）,其它各组两两之间均存在统计学差异（P〈0.05）。实验组检测气体体积呈先下降后上升趋势,CO2浓度上下波动,气体成分均符合典型空气栓塞气体成分标准;16d对照组气体接近于腐败气体。结论兔静脉空气栓塞气体体积在死后16d内呈先轻微下降后上升的规律;静脉空气栓塞死后8d内检测结果准确、可靠,而8~16d的检测结果需结合其他证据综合分析,才能确定是否为静脉空气栓塞致死。     

Fatal decompression sickness following therapeutic hyperbaric environment (author's transl)

In Hannover/Germany in 1976 a so called "Society for Regenerative Hyperbaric Therapy" (Gesellschaft für Regenerative Uberdruck-Therapie) subjected 20 patients within two coupled multi-place chambers to a simulated hyperbaric environment, equivalent to a maximum of 4 ata, followed usually by gradual reductions of the pressure. The patients were of an average age of 67.2 years and were afflicted by various disorders. During one of the "dives" a patient developed air embolism of the central nervous system. During ensuing confusion of the chamber was opened suddenly, with resultant explosive reduction of the high pressure. This resulted in five letal accidents of decompression sickness. Post mortem examination revealed diffuse distribution of gas bubbles throughout the entire body. By elecronmicroscopy each bubble was covered by an osmiophilic coat. Post mortem findings are discussed and correlated with well-known and new clinical symptomes. These observations present for the first time fatal accidents of decompression sickness in humans, associated with hyperbaric air-therapy.     

Traumatic venous aneurysm of the popliteal vein with outcome: a case report and review of the literature.

A case of sudden death due to recurrent pulmonary thromboembolism is described. The fatality took place three and a half weeks following blunt trauma to the left popliteal region. The patient died unexpectedly. Autopsy revealed the source of the emboli as a sacciform venous aneurysm of the popliteal vein, an entity seldom described, but important to consider in cases of soft tissue popliteal masses or unexplained pulmonary embolism, especially in otherwise healthy individuals.     

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.     

Unusual death of a farmer.

A farmer was found dead, in a pool of blood on his farm. Evidence indicated that the farmer had dragged himself or been dragged from the stable to the point where his body was found. With the exception of abrasions in the face, there were no other signs of injury. An autopsy revealed a depressed fracture of the skull and showed a venous air embolism to be the cause of death. The medicolegal interpretation of the findings left no doubt that the farmer was killed by a cow.     

Unexpected sudden death from coronary sinus thrombosis. An unusual complication of central venous catheterization

Coronary sinus thrombosis is an unusual but potentially serious complication of the use of central venous devices. We report a fatal case of coronary sinus thrombosis in relation to a malpositioned central venous catheter. The death occurred very soon following the beginning of symptoms and the cause could not be suspected. Direct trauma of the catheter on the coronary sinus endothelium seems the most probable cause of the thrombosis.     

Arterial Perfusion—A Useful Technique for Evaluating Incised Wounds

A 54‐year‐old woman was found deceased with incised wounds of both sides of her neck and both wrists. Postmortem CT scanning revealed air in the heart and in the dural veins in continuity with air in the right jugular vein. Death was due to incised wounds of the wrist and neck with blood loss and air embolism. The manner of death was suicide. At autopsy, perfusion of the thoracic ascending aorta produced a fine stream of water emanating from an incised wound of the right ulnar artery with no significant leakage of water from the wound of the left wrist. There was also leakage from the facial artery branch of the right external carotid artery. Perfusion testing can be used as a screening test prior to formal dissection and also to identify small vessels that may not be obvious on standard examination of an exsanguinated field.