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

Characterization and comparison of a 2-, 4- and 8-MHz central venous catheter ultrasound probe for venous air emboli detection

This paper presents a concept for detection of venous air emboli inside the superior vena cava using a central venous catheter with integrated Doppler ultrasound transducer installed on the tip. Several Doppler probes each with a single insonation frequencies of 2 MHz, 4 MHz or 8 MHz are characterized and compared for usefulness in this scenario. During in vitro experiments using an artificial blood circulatory with blood mimicking fluid bubbles with defined volumes were injected and recorded as gaseous embolic events. The in vitro results of measured embolus-blood-ratio values (EBR) in respect to the air bubbles volumes and its echogenicity showed a good correlation with the simulation model of spherical cross section scattering of such air bubbles. It is shown that the probe design still needs some improvements using a 4 MHz insonation frequency to get a useable detection sensitivity in such scenario within vena cava superior. The results suggest that it is possible to estimate the air bubble volume corresponding to the EBR using such a catheter probe.

Spontaneous Absorption of Cerebral Air Embolus Developed Accidentally during an Intra-arterial Procedure

Cerebral arterial air embolism (CAAE), although infrequent, is a complication that can occur at any time during an invasive medical procedure. We experienced two cases of CAAE during cerebral angiography accidentally. The author reports the two cases of CAAE wherein air emboli dissolved spontaneously and immediately under normal atmospheric pressure, not under therapeutic hyperbaric environment. One of the cases shows entire dissolution of the air embolus on the moving image. This report shows that arterial air embolus can be absorbed spontaneously, and air embolus size is one of the factors that influence air embolus dissolution besides hyperbaric oxygen condition.

Air Embolism: Practical Tips for Prevention and Treatment

Air embolism is a rarely encountered but much dreaded complication of surgical procedures that can cause serious harm, including death. Cases that involve the use of endovascular techniques have a higher risk of air embolism; therefore, a heightened awareness of this complication is warranted. In particular, central venous catheters and arterial catheters that are often placed and removed in most hospitals by a variety of medical practitioners are at especially high risk for air embolism. With appropriate precautions and techniques it can be preventable. This article reviews the causes of air embolism, clinical management and prevention techniques.

Acute stroke from air embolism to the middle cerebral artery following upper gastrointestinal endoscopy

Acute stroke from cerebral-artery air embolism is a very rare occurrence during esophagogastroduodenoscopy (EGD). Computed tomography is a quick and reliable method of detecting cerebral air embolism if performed within an appropriate timeframe. We found 20 reported cases of air embolism with EGD in the literature; only seven of those resulted in cerebral air embolus. We report an eighth such case in which the patient suffered cerebral air embolus with neurological signs of a stroke while undergoing upper gastrointestinal endoscopy.

Cerebral air embolism following transbronchial lung biopsy during flexible bronchoscopy

During a diagnostic flexible bronchoscopy an 84 year old patient suffered a sudden reduction in conscious level following a transbronchial lung biopsy. A subsequent computed tomography brain scan confirmed cerebral air emboli. The patient survived following a period of supportive treatment in the critical care unit. Transbronchial lung biopsy may cause disruption of vessels walls within the lung parenchyma. Increased airway pressure, caused by the patient exhaling against a bronchoscope wedged within a segmental bronchi, may subsequently force air bubbles through the vessel wall defects. This may explain the occurrence of air emboli. This is a rare report of air embolism complicating transbronchial lung biopsy and all bronchoscopists should aware of this potentially fatal complication.

Cerebral air embolism complicating CT-guided trans-thoracic needle biopsy of the lung

BACKGROUND AND AIMS

Systemic air embolism is recognized as a rare but potentially fatal complication of trans-thoracic needle biopsy of the lung.

METHODS

  We report the case of a young female who developed fatal cerebral air embolism following computed tomography (CT) guided needle biopsy of a lung mass.

RESULTS

Immediately after the procedure, the patient went into cardio-respiratory arrest. Despite adequate resuscitation and ventilatory support, she showed little recovery in her neurological status and subsequently died. CT scan of the brain confirmed cerebral arterial air embolism.

CONCLUSION

Radiologists and physicians need to be aware of this rare but potentially fatal complication of needle lung biopsy.

Hyperventilation impairs brain function in acute cerebral air embolism in pigs

OBJECTIVE

To evaluate, in a model of cerebral air embolism (CAE), the effects of ventilation-induced hypocapnia and hyperoxemia on intracranial pressure (ICP), cerebral perfusion pressure (CPP), brain oxygen (PbrO(2)), brain carbon dioxide (PbrCO(2)), brain pH (brpH) and levels of brain glucose and lactate.

DESIGN AND SETTING

Prospective animal study in a university medical center.

SUBJECTS

Fifteen Landrace/Yorkshire pigs.

INTERVENTIONS

In 15 anesthetized pigs ICP, PbrO(2), PbrCO(2) and brpH were measured with multi-parameter sensors, and brain glucose and lactate by microdialysis. All these parameters were recorded for 2 h after injection of air into the internal carotid artery. Nine animals were hyperventilated (PaCO(2 )+/-25 mmHg) and hyperoxygenated (FiO(2) 1.0) and six animals were normoventilated (PaCO(2)()+/-40 mmHg with an FiO(2) 0.4) and served as controls. RESULTS. In the treatment group the ICP rose from 8+/-1 to 52+/-6 mmHg, which was similar to that in the control group (12+/-1 to 57+/-8 mmHg). At the end of the 2-h study period, there were no significant differences in PbrO(2), PbrCO(2) and brpH between the two groups. The decreased brain glucose and increased brain lactate reached severe pathological values in both groups by the end of the 2-h study period.

CONCLUSIONS

Hypocapnia and hyperoxemia in acute CAE did not improve pathological functional brain parameters compared with normoventilated controls. Similarly, the pathological changes in brain glucose/lactate could also not be improved by hypocapnia and hyperoxemia.

Air embolism as a cause of the systemic inflammatory response syndrome: a case report

We describe a case of systemic inflammatory response syndrome associated with air embolism following the removal of a central line catheter, coupled with a deep inspiratory maneuver. The presence of a patent foramen ovale allowed the passage of a clinically significant amount of air from the venous circulation to the systemic circulation. The interaction of air with the systemic arterial endothelium may have triggered the release of endothelium-derived cytokines, resulting in the physiologic response of systemic inflammatory response syndrome.