CT demonstration of massive cerebral air embolism from pulmonary barotrauma due to cardiopulmonary resuscitation

Postmortem computed tomography of gas gangrene with aortic gas in a dialysis patient

Recently, postmortem imaging is sometimes used as an alternative to conventional autopsy. However, there are few case reports of postmortem imaging of dialysis patients. Here, we report a fatal case of gas gangrene involving a 76-year-old man who underwent dialysis. He died suddenly before a diagnosis could be established. Immediately after his death, postmortem computed tomography (PMCT) revealed gas accumulation in his right upper extremity and ascending aorta. Gas gangrene progresses rapidly and may sometimes result in sudden death before it is diagnosed. In this case, PMCT findings were useful to diagnose gas gangrene. Intravascular gas is a common finding on PMCT and is generally caused by cardiopulmonary resuscitation and decomposition. However, the detection of gas in the ascending aorta by PMCT was not described previously. Moreover, Gram stain and culture of the exudate showed anaerobic Gram-positive bacilli which suggested that the gas generation in the blood was caused by Clostridia species. To the best our knowledge, this is the first report of a dialysis patient whose cause of death was determined as gas gangrene using PMCT.

Massive systemic arterial air embolism caused by an air shunt after blunt chest trauma: A case report

INTRODUCTION

Systemic arterial air embolism (SAAE) is a rare but fatal condition, with only a few cases reported, and the detailed etiology underlying SAAE remains unknown. We report a first case of massive SAAE after blunt chest injury, wherein the presence of traumatic air shunt was confirmed by direct observation during surgery. We also summarize our experience with six other SAAE cases.

PRESENTATION OF CASE

A 68-year-old woman was admitted in a state of cardiac arrest after a fall. Emergency room thoracotomy determined complete transection of left main bronchus and left superior pulmonary vein. Postmortem computed tomography (CT) revealed full of air in the aortic arch, the descending aorta, and the great vessels. Therefore, one of the cause of death might be SAAE.

DISCUSSION

An air shunt after blunt chest trauma can cause SAAE, and clinical signs and operative findings can provide clues for possible SAAE. The bronchopulmonary vein fistula, the aortic injury and full-thickness myocardial injury have the potential to become traumatic air shunts. In cases with a coexisting air shunt, pneumothorax, lung contusions and positive-pressure ventilation can be risk factors for SAAE, as sources of air continually entering the systemic arterial circulation.

CONCLUSION

SAAE is caused by an air shunt following trauma. Clinical signs and operative findings summarized in this case should aid in the recognition of possible SAAE.

Medical Disorders Related to Diving

Exposure to the underwater environment is associated with several unique disorders that may require recompression in a hyperbaric chamber. Increasing pressure during descent reduces the volume of the paranasal sinuses and middle ear, which, if not properly equalized, will sustain injury due to barotrauma. Barotrauma of the inner ear results in vertigo, tinnitus, and often permanent hearing loss. During ascent, expanding gas can produce lung injury accompanied by pneumothorax, mediastinal and subcutaneous emphysema, injection of air into the pulmonary veins, and arterial air embolism to the brain. Divers with pulmonary barotrauma often present with unconsciousness, seizures, or other evidence of cerebral dysfunction. Rapid treatment with recompression often reverses the cerebral deficits. Air embolism lesions are usually diffuse, in contradistinction to a stroke which usually follows the distribution of a single cerebral artery. Decompression sickness is a disorder caused by evolution of supersaturated dissolved gas in tissues and blood following exposure to increased pressure. Protocols for avoiding excess supersaturation during ascent from depth have been available for more than 100 years, and diving is considered safe when established decompression schedules are followed. Decompression sickness causes pain in the joints of the upper and lower extremities, and can injure the spinal cord. Paralysis, paresthesias, sensory loss, and bowel and bladder paralysis accompany spinal cord injury. Treatment involves recompression and oxygen. Platelet inhibitors and other anti-inflammatory drugs are also useful. A diving disorder must be considered in any patient with a neurologic syndrome, vertigo, hearing loss, or joint pain following diving.

Common Postmortem Computed Tomography Findings Following Atraumatic Death: Differentiation between Normal Postmortem Changes and Pathologic Lesions

Computed tomography (CT) is widely used in postmortem investigations as an adjunct to the traditional autopsy in forensic medicine. To date, several studies have described postmortem CT findings as being caused by normal postmortem changes. However, on interpretation, postmortem CT findings that are seemingly due to normal postmortem changes initially, may not have been mere postmortem artifacts. In this pictorial essay, we describe the common postmortem CT findings in cases of atraumatic in-hospital death and describe the diagnostic pitfalls of normal postmortem changes that can mimic real pathologic lesions.

Arterial air emboli on computed tomography (CT) autopsy

OBJECTIVE

To describe radiological appearances of systemic air emboli versus intravascular air from putrefaction.

MATERIALS AND METHODS

The hospital trauma database was searched for patients who underwent computed tomography (CT) autopsy. The studies were reviewed and evaluated for intravascular gas. The appearances and location of intravascular air were characterised.

RESULTS

Four cases of intravascular gas were identified out of 15 cases of CT autopsy performed from March 2004 to December 2006. In three cases, intravascular air was predominantly in the arterial system, coupled with severe pulmonary injury. In one case, the air was predominantly in the venous system with a large amount of gas in portal veins.

CONCLUSION

We propose to consider pulmonary alveoli-venous fistula as a possible cause of systemic air emboli, as identified on CT autopsy by large amounts of gas in the arterial circulation, coupled with severe pulmonary injury.

Intravascular gas distribution in the upper abdomen of non-traumatic in-hospital death cases on postmortem computed tomography

OBJECTIVES

To investigate the occurrence of intravascular gas in the liver, kidneys, spleen, and pancreas by postmortem computed tomography (PMCT) in cases of non-traumatic in-hospital deaths and elucidate the relationship between the PMCT data and clinical information or autopsy results.

METHODS

The study included 45 cadavers of patients who died while receiving treatment in our academic tertiary-care hospital between April and December 2009. All subjects underwent PMCT and conventional autopsy. The appearance of postmortem gas in the liver, kidney, spleen, and pancreas was assessed using PMCT and scored using a subjective scale (liver, L0-L3; kidney, K0-K2; spleen, S0-S1; and pancreas, P0-P1), and the distribution of gases in the vessels of the liver (arteries, veins, and portal veins) was analyzed. The relationship between the gas score and time elapsed since death, cardiopulmonary resuscitation (CPR), administration of antibiotics, a history of bacteremia, or cause of death was assessed statistically.

RESULTS

Positive correlations were found between administration of CPR and liver and kidney gas scores (P=0.008 and 0.002, respectively), but not with spleen and pancreas gas (P=0.291 and 0.535, respectively). No significant relationship between distribution of gas in the vessels of the liver and CPR was found. No other significant correlations between gas and any of the other parameters described above were found. While significant correlations were detected in no-CPR cases between liver gas, kidney gas, spleen gas, and pancreas gas (P<0.001 for all six combinations), no correlation between these parameters was detected in the CPR cases.

CONCLUSIONS

The present study was the first statistical analysis of intravascular gas in the liver, kidneys, spleen, and pancreas by using PMCT in non-traumatic in-hospital death cases. The results showed that PMCT in the presence and absence of CPR reveals differences in intraorgan gas distribution. In addition, the detection of intraorgan gas on PMCT cannot be used to predict time elapsed since death, and it is not affected by the administration of antibiotics, a history of bacteremia, and cause of death. Awareness of these postmortem changes is important for the accurate interpretation of PMCT results.

Cerebral air embolism: acute imaging

Iatrogenic cerebral air embolism secondary to right subclavian vein recatheterization was imaged acutely by computed tomography (CT) and magnetic resonance imaging (MRI). However, CT showed intravascular air with misleadingly high attenuation values sampled to a minimum of -39 HU. Diffusion-weighted imaging, not previously reported in this setting, clearly showed hyperintense acute infarctions in corresponding vascular territories 8.5 hours postprocedure (less than 6 hours after referable symptomatology noted), whereas T2-weighted fluid-attenuated inversion recovery and turbo gradient spin echo images did not. The combination of CT and diffusion-weighted MRI appears ideal for evaluating suspected cerebral air embolism in the acute setting.

Frequent and rare complications of resuscitation attempts

INTRODUCTION

Resuscitation attempts require invasive iatrogenic manipulations on the patient. On the one hand, these measures are essential for survival, but on the other hand can damage the patient and thus contain a significant violation risk of both medical and forensic relevance for the patient and the physician. We differentiate between frequent and rare resuscitation-related injuries. Factors of influence are duration and intensity of the resuscitation attempts, sex and age of the patient as well as an anticoagulant medication.

MATERIALS AND METHODS

Review of current literature and report on autopsy cases from our institute (approximately 1,000 autopsies per year).

RESULTS

Frequent findings are lesions of tracheal structures and bony chest fractures. Rare injuries are lesions of pleura, pericardium, myocardium and other internal organs as well as vessels, intubation-related damages of neural and cartilaginous structures in the larynx and perforations of abdominal organs such as liver, stomach and spleen.

CONCLUSION

We differentiate between frequent and rare complications. The risk of iatrogenic CPR-related trauma is even present with adequate execution of CPR measures and should not question the employment of proven medical techniques.

Systemic air embolism after cardiopulmonary resuscitation in a preterm infant

We report a preterm infant with extensive systemic air embolism after cardiopulmonary resuscitation for cardiac arrest due to an occluding thrombus in the inferior vena cava. After excluding other potential causes (air infusion, necrotizing enterocolitis or pulmonary leakage syndrome), we postulate that the pressure gradient needed for air embolism to occur is related to the resuscitation procedure. An important clue of air embolism was noted on the chest X-ray taken before death showing intracardial air.

CONCLUSION

Systemic air embolism may occur as a very rare complication after cardiopulmonary resuscitation.

Cerebral arterial air embolism in a child after intraosseous infusion

Cerebral arterial air embolism (CAAE) has been reported as a rare complication of medical intervention. There has been one reported case of CAAE after the use of an intraosseous infusion (IO) system. We report on a case of CAAE after tibial IO infusion in a 7-month-old girl during resuscitation.

Arterial cerebral air embolism at the site of a spontaneous pontine hemorrhage in a patient receiving erroneous continuous positive pressure ventilation

We report the case of a 48-year-old male with iatrogenic arterial cerebral air embolism at the site of a spontaneous pontine hemorrhage. The patient inadvertently received continuous positive pressure ventilation without exhalation for a few minutes, resulting in pneumothorax, interstitial emphysema, pneumoperitoneum, and arterial cerebral air embolism at the site of the intracerebral hemorrhage. This is the first report of pneumocephalus without head trauma or previous surgery in which the air embolism occurs at the site of a spontaneous intracerebral hemorrhage. We hypothesize that air preferentially leaked into the brain parenchyma through the weakened perforating pontine artery that caused the intracerebral bleeding.

Massive cerebral air embolism after cardiopulmonary resuscitation

We report a case of massive intracerebral air embolism after cardiopulmonary resuscitation in a patient with a fatal head injury. There was no pneumothorax or extravascular pneumocephalus, however, air was found in the internal carotid artery. Massive cerebral air embolism may occur after entrance of air into the circulatory system via ruptured pulmonary vessels during cardiopulmonary resuscitation.

Massive intracerebral air embolism associated with meningitis and lumbar spondylitis: case report

BACKGROUND

Massive intracerebral air embolism is a rare pathologic state and never in association with meningitis and lumbar spondylitis. To the best of our knowledge, our presented case is the first of a massive intracerebral air embolism associated with meningitis and lumbar spondylitis of Klebsiella pneumonia.

CASE DESCRIPTION

A 55-year-old man presented with a high fever and low back pain. Blood culture showed Klebsiella pneumonia. Lumbar computed tomography (CT) revealed discitis at L1-2 and L2-3 levels and paraspinal abscess in which air was found. Despite management with antibiotics, patient's consciousness deteriorated, and brain CT revealed diffuse intravenous air embolism and severe brain swelling. Cerebrospinal fluid (CSF) examination demonstrated bacterial meningitis, and the CSF culture showed Klebsiella pneumonia. Later, septic shock occurred and patient expired.

CONCLUSION

Intracerebral air embolism can occur in the Klebsiella pneumonia meningitis that resulted from lumbar spondylitis and sepsis.

Recommendations for hyperbaric oxygen therapy of cerebral air embolism based on a mathematical model of bubble absorption

Transcranial doppler studies show that microscopic cerebral artery air emboli (CAAE) are present in virtually all patients undergoing cardiac surgery. Massive cerebral arterial air embolism is rare. If it occurs, hyperbaric oxygen therapy (HBO) is recommended as soon as surgery is completed. We used a mathematical model to predict the absorption time of CAAE, assuming that the volumes of clinically relevant CAAE vary from 10(-7) to at least 10(-1) mL. Absorption times are predicted to be at least 40 h during oxygenation using breathing gas mixtures of fraction of inspired oxygen approximately equal to 40%. When CAAE are large enough to be detected by computerized tomography, absorption times are calculated to be at least 15 h. Decreases in cerebral blood flow caused by the CAAE would make the absorption even slower. Our analysis suggests that if the diagnosis of massive CAAE is suspected, computerized tomography should be performed, and consideration should be given to HBO therapy if the CAAE are large enough to be visualized, even if patient transfer to a HBO facility will require several hours.

Massive cerebral air embolism following cardiopulmonary resuscitation. Report of two cases

Cerebral air embolism can occur in a number of situations. We report two cases of massive cerebral arterial air embolism following cardiopulmonary resuscitation, and its mechanism is discussed.

Massive air embolism complicating Nd-YAG laser endobronchial photoresection

A 63 year old male underwent 6,900 rads of external radiation for a squamous cell carcinoma of the left main bronchus. Recurrence of the tumor 8 months later was treated with 6,618 joules and patency of the left main bronchus was restored. Four months later, he developed complete atelectasis of the left lung requiring repeat laser. During the procedure he became hypotensive, bradycardic, and hypoxic due to a tension pneumothorax. Although treated promptly with thoracostomy tube drainage, the patient never awakened. CT scan of the brain demonstrated anoxic encephalopathy with air present in the right frontal lobe. Brain death was confirmed by an EEG and cerebral angiogram. Air embolism has been reported in conjunction with diagnostic procedures including therapeutic pneumothorax for tuberculosis, transthoracic needle biopsy of the lung, and positive pressure ventilation with or without pneumothorax. The only reported case of air embolism associated with laser was a small middle cerebral artery cerebro-vascular accident which was self limited. Its mechanism is unclear, but it is suspected to be due to a communication between a pulmonary vein and the atmosphere. A greater volume of air will enter the damaged vessel in the setting of positive pressure ventilation and/or a tension pneumothorax. When neurologic manifestations are present, hyperbaric oxygen therapy is the treatment of choice. Prompt institution in hemodynamically stable patients can minimize neurologic sequelae.