Tracheostomy: Sudden Death from Delayed Air Embolism

Venous air embolus during percutaneous dilatational tracheostomy: A case report

We describe the first case of venous air embolism during percutaneous tracheostomy performed during continuous renal replacement therapy with citrate anticoagulation. Venous air embolism is a known risk during percutaneous dilatational tracheostomy; concurrent use of extracorporeal circuits may present a compounded risk due to the negative pressure developed by the blood pump. Use of regional citrate anticoagulation, permitting invasive procedures to be performed without discontinuing renal replacement therapy, may lead to an increase in the incidence of venous air embolism during tracheostomy.

Fatal air embolism as complication of percutaneous dilatational tracheostomy on venovenous extracorporeal membrane oxygenation, two case reports

BACKGROUND

Tracheostomy is recommended in case of prolonged mechanical ventilation. Therefore, most patients with an indication for venovenous extracorporeal membrane oxygenation (ECMO) will also have an indication for tracheostomy.

CASE PRESENTATION

We report 2 cases of fatal air embolism into the ECMO system as complication of percutaneous dilatational tracheostomy. Both patients had an AVALON ELITE® bi-caval cannula implanted draining blood from the vena cava superior and inferior.

CONCLUSION

Since there is limited safety data on this specific group of patients, a routine early dilatational tracheostomy might be associated with a significant risk.

Gas Embolism: Part I. Venous Gas Emboli

Gas emboli syndromes occur in many different settings, and their medical significance ranges from being life-threatening emergencies to being totally innocuous. We discuss venous gas embolization in Part I of this review, and it can result from a variety of traumatic, diagnostic, therapeutic, and surgical interventions. The pathophysiological consequences depend on where the gas bubbles impact and obstruct the circulation—by creating an “air lock” in the right ventricle, by obstruction of pulmonary arterioles, and sometimes with passage into the arterial circulation (so called paradoxical emboli). Various monitoring techniques are available and are known to be useful in high-risk patients. Nevertheless, the diagnosis can be difficult to establish. Myriad and generally nonspecific clinical manifestations may be present; the patient may often exhibit signs and symptoms suggestive of other acute cardiopulmonary or central nervous system events. The classically described “mill-wheel murmur” is actually a rare finding, and it is transient at best. There are no specific diagnostic tests available, and clinicians, must depend on a high level of suspicion in the appropriate settings. Rapid identification of the problem, with prevention of further gas entry into the venous circulation, should be a routine measure. The left lateral decubitus position, administration of 100% oxygen, and hyperbaric oxygenation should all be considered, and they have been shown to be effective treatment modalities.

Evaluation of catheter placement in the treatment of venous air embolism

Venous air embolism is a potential complication of many surgical, therapeutic, and diagnostic procedures. Aspiration of air via a catheter placed in the superior vena cava or right atrium or placed in the pulmonary outflow tract and pulled through the right heart chambers had been advocated for the treatment of venous air embolism. In this study, three catheter positions were analyzed to determine which was best for removal of gas after induction of massive venous air embolism in dogs. In 18 dogs, 9 of which were suspended by their forelegs to simulate the sitting position used in posterior fossa exploration and 9 of which were supine, a Swan-Ganz catheter was placed in the right atrium, right ventricle, or pulmonary artery. A measured amount of air was injected into the left jugular vein and syringe aspiration of the air was attempted through the catheter. In the group with the catheter in the pulmonary artery, aspiration was continuous while the catheter was withdrawn through the right heart chambers. The amount of air aspirated varied widely among the three catheter positions, and no one catheter position proved superior to the other two.

Pulmonary air embolism during insertion of a permanent transvenous cardiac pacemaker

In two patients pulmonary air embolism was a complication of the implantation of a permanent transvenous cardiac pacemaker. One of these patients, in whom air embolism was documented by cinefluorograms, is described in detail. Cinefluorograms demonstrated air in the right ventricle and main pulmonary artery with clear visualization of the opening and closing of the pulmonary valve. Both patients were treated conservatively by use of the left lateral decubitus position and administration of oxygen. The pathophysiology, hazards, and therapy of this complication are reviewed. Massive pulmonary air embolism is potentially fatal, and special care with regard to insertion of the electrode catheter should be taken in order to prevent it.