Systemic air embolism during laser bronchoscopy

Cerebral air embolism complicating transbronchial lung biopsy: A case report

BACKGROUND

In this case report we describe an extremely rare case of cerebral air embolism following transbronchial lung biopsy (TBLB). Only a few cases of this rare complication were described previously. Every bronchologist should recognize this severe adverse event. Prompt recognition of this complication is mandatory in order to initiate supportive measures and consider hyperbaric oxygen therapy.

CASE SUMMARY

In this case report we describe an extremely rare case of cerebral air embolism following TBLB. Only a few cases of this rare complication were described previously. Our patient had an incidental finding of lung tumour and pulmonary emphysema. Cerebral air embolism developed during bronchoscopy procedure, immediately after the third trans-bronchial lung biopsy sample and caused cerebral ischaemia of the right hemisphere and severe left-sided hemiplegia. Despite timely initiation of hyperbaric oxygen therapy hemiplegia didn´t resolve and the patient died several weeks later. Cerebral air embolism is an extremely rare complication of TBLB. This condition should be considered in case the patient remains unresponsive or presents with acute neurological symptoms in the post-intervention period since early recognition, diagnosis and hyperbaric oxygen therapy initiation are key factors determining the patient´s outcome.

CONCLUSION

Within this report, we conclude that air/gas embolism is an extremely rare complication after TBLB, which should be considered in case the patient remains unresponsive or presents with acute neurological symptoms in the post-intervention period after bronchoscopy. The current gold standard for diagnosis is computed tomography scan of the head. After recognition of this complication we suggest immediate hyperbaric oxygen therapy, if available.

Fatal systemic (paradoxical) air embolism diagnosed by postmortem funduscopy

Air embolism is often unrecognized and underreported. Published case reports or case series describe only rare fundal examinations of retinal air emboli (RAE)-a distinctive sign of systemic air embolism. We report an infant, found unresponsive at home, who died in the emergency department after unsuccessful resuscitative efforts. Before the autopsy, diagnostic RAE were recognized and imaged during postmortem funduscopy. Postmortem radiography and an autopsy confirmed systemic (paradoxical) air embolism due to inflicted abdominal and thoracic blunt force injuries. While a few descriptions and illustrations of RAE occur in case reports, we found no published photographic images of RAE in infants, children, or adults. This case report describes and photographically documents classic RAE associated with fatal systemic (paradoxical) air embolism. Complementing postmortem radiography and judicious autopsy techniques, the detection of RAE can aid pathologists in diagnosing systemic air embolism.

Vascular Air Embolism During Bronchoscopy Procedures- Incidence, Pathophysiology, Diagnosis, Management and Outcomes

Vascular air embolism (VAE) is a rare, but potentially fatal complication of invasive medical or surgical procedures. It is a very rare complication of bronchoscopy and is most frequently reported with therapeutic bronchoscopy with Argon plasma coagulation (APC) or neodymium-doped yttrium aluminum garnet (Nd-YAG) laser. Despite being rare, as a result of its high chance of mortality and morbidity, it is imperative that physicians have high clinical suspicion to allow for early recognition and treatment. In this article, we provide a concise review of the incidence, pathophysiology, diagnosis management and outcomes of air embolism during bronchoscopy procedures.

Common uses and cited complications of energy in surgery

BACKGROUND

Instruments that apply energy to cut, coagulate, and dissect tissue with minimal bleeding facilitate surgery. The improper use of energy devices may increase patient morbidity and mortality. The current article reviews various energy sources in terms of their common uses and safe practices.

METHODS

For the purpose of this review, a general search was conducted through NCBI, SpringerLink, and Google. Articles describing laparoscopic or minimally invasive surgeries using single or multiple energy sources are considered, as are articles comparing various commercial energy devices in laboratory settings. Keywords, such as laparoscopy, energy, laser, electrosurgery, monopolar, bipolar, harmonic, ultrasonic, cryosurgery, argon beam, laser, complications, and death were used in the search.

RESULTS

A review of the literature shows that the performance of the energy devices depends upon the type of procedure. There is no consensus as to which device is optimal for a given procedure. The technical skill level of the surgeon and the knowledge about the devices are both important factors in deciding safe outcomes.

CONCLUSIONS

As new energy devices enter the market increases, surgeons should be aware of their indicated use in laparoscopic, endoscopic, and open surgery.

Transient transmural ischaemia during endobronchial laser treatment: possible coronary artery embolism

We report the case of a 51-year-old woman receiving endobronchial treatment with neodymium:yttrium garnet laser After 30 minutes of stable anaesthesia and laser treatment, sudden inferior myocardial ischaemia developed followed by haemodynamic collapse. Resuscitation with fluids, pressors, atropine and esmolol was successful, leading to rapid resolution of the ischaemia and full recovery. The sudden onset and time course of the ST segment elevation was consistent with coronary artery air embolism, as occurs occasionally during cardiac surgery. Systemic gas embolism during endobronchial laser treatment has been previously reported with poor outcomes and significant mortality. This complication can be avoided with awareness of the mechanism while appropriate monitoring may allow early detection and successful treatment.

Gas flow during bronchoscopic ablation therapy causes gas emboli to the heart: a comparative animal study

BACKGROUND

Thermal ablation is one of the most commonly used modalities to treat central airway obstruction. Both laser and argon plasma coagulation (APC) have been reported to cause gas emboli and cardiac arrest. We sought to determine whether bronchoscopic ablation therapy can result in systemic gas emboli, correlate their presence with the rate of gas flow, and establish whether a zero-flow (ZF) modality would result in the significant reduction or elimination of emboli.

METHODS

CO(2) laser delivered through a photonic bandgap fiber (PBF) and APC were applied in the trachea and mainstem bronchi of six anesthetized sheep at varying dosages and gas flow rates. Direct epicardial echocardiography was used to obtain a four-chamber view and detect gas emboli.

RESULTS

The presence of gas flow accompanying APC and the CO(2) laser with forward flow correlated significantly with the appearance of gas bubbles in the atria. A definite dose response was observed between the gas flow rate and the number of bubbles seen. When the CO(2) laser was delivered through a PBF with ZF to the trachea or bronchi, no bubbles were observed.

CONCLUSION

Bronchoscopic thermal ablation therapy using gas flow is associated with gas emboli in a dose-dependent fashion. The use of the flexible PBF with ZF is not associated with the development of gas emboli. Further study is required to determine whether a clinically safe threshold of gas emboli exists, and the relationships among the pathologic depth of tissue destruction, gas flow, pulse duration, and the development of gas emboli.

Endobronchial laser therapy

We have sought to briefly outline the history and current role of laser therapy in airway obstruction. A primary goal in the use of laser therapy is the safe, effective, and rapid palliation of symptoms owing to tracheal or bronchial obstruction. This seems clearly supported in the literature despite some variation in definitions as to measurement of success. Objective criteria for improvement has also been studied, with authors noting improvement in walk tests, spirometric studies, and caliber of airways after treatment in significant percentages of patients. Patient survival, as noted by Ramser and Beamis, may not be the proper endpoint when discussing therapy, which for malignant causes, is meant to be palliative. Noting this, there are many benign conditions that may be effectively treated with laser therapy with a possible "cure" for some lesions defined as "carcinoma in situ." We believe laser therapy in the treatment of airway obstruction is an important tool that has proven beneficial in the therapy of benign and malignant lesions of the airway. Although future studies should prospectively examine survival characteristics, the current evidence firmly supports the use of laser as a useful modality of therapy in our endeavors to provide palliative and potentially curative care to our patients with lung disease.

[Gas embolism during endonasal YAG laser surgery]

The authors describe a case of air embolism during an endonasal YAG laser surgery in a 10-year-old child. This accident was caused by the coaxial air cooling system of the laser ruby tip. The importance of end tidal CO2 monitoring and precordial auscultation during laser surgery even in patients without risk factors is underlined.

Systemic air embolism as a possible cause of cardiac arrest during endoscopic treatment of pulmonary haemangioma using a diode laser

Air embolism is a known but rare complication to endoscopic laser surgery. A case of nearly lethal air emboli as a complication to endoscopic laser surgery using a diode laser in the lungs is described. The case illustrates that even after prolonged resuscitation a successful outcome can be obtained.

Pathogenesis of systemic air embolism during bronchoscopic Nd:YAG laser operations

BACKGROUND

The occurrence of systemic air embolism during bronchoscopic neodymium:yttrium-aluminum garnet laser operations has been suspected. Here we describe its mechanism.

METHODS

Two patients with embolic cardiac and neurologic complications after bronchoscopic neodymium: yttrium-aluminum garnet laser tumor ablation are described. A subsequent third patient was monitored for intracardiac and aortic air by transesophageal echocardiography. A review of the literature and safety recommendations are discussed.

RESULTS

The appearance of systemic air emboli was related to the use of the laser fiber air coolant at high flow and resolved by decreasing the air flow. The presence of intracardiac and aortic air was associated with hypotension and inferior ischemic electrocardiographic changes.

CONCLUSIONS

Systemic air embolism during bronchoscopic laser operations is a potentially catastrophic complication and is related to the use of gas-cooled laser fibers and contact probes. We recommend using the noncontact mode whenever possible and maintaining the coaxial coolant air flow at the minimum level or using a fluid coolant if contact is necessary.

Anesthetic management of laser surgery for central airway obstruction: a 12-year case series

The retrospective 12-year experience of anesthetizing patients with central airway obstructions for laser treatment with a CO2 and two types of Nd:YAG laser has been reviewed and evaluated. More than 300 patients have been treated, many on several occasions. The beneficial effects of treatment to the majority of patients have been significant. There has been a small associated mortality because the majority are in the high-risk categories of fitness for anesthesia, but no clinical evidence that it is directly attributable to the techniques of anesthesia or ventilation. Therefore, although laser technology has evolved into systems suitable to be applied with fiberoptic bronchoscopes and local and sedation anesthesia, the use of a rigid bronchoscope and the evolved techniques of anesthesia and ventilation remain appropriate to the clinical needs and offer advantages.

Gas Embolism: Part II. Arterial Gas Embolism and Decompression Sickness

Gas emboli syndromes are known to occur in many different settings, and they may result in life-threatening emergencies. Venous gas embolization was discussed previously in Part I of this review. Gas emboli that gain access to the arterial circulation or that result from exposures to decreased ambient pressures in the environment are discussed in Part II. The prevalence of arterial gas emboli and decompression sickness are likely not as high as for venous gas emboli. Most cases are preventable, and prompt treatment is frequently effective. Once present, gas bubbles generally distribute themselves throughout the body based on the relative blood flow at the time, thus making the nervous system, heart, lung, and skin the primary organ systems involved. Both mechanical and biophysical effects lead to intravascular and extracellular alterations that result in tissue injury. The clinical manifestations of these disorders are varied, and a high index of suspicion in the appropriate settings will aid health care providers in prompt recognition of these problems and allow timely intervention with specific therapy. Management of arterial gas emboli and decompression sickness is similar, with a focus on hyberbaric chamber therapy and intermittent hyperoxygenation. Recompression schedules in current use have withstood the test of time. Research continues to refine our understanding of these diseases and to optimize the treatment regimens available.

Fatal gas embolism as a complication of Nd-YAG laser surgery during treatment of bilateral choanal stenosis

A 40-day-old infant boy underwent Nd-YAG laser surgery because of congenital bilateral choanal stenosis. Cyanosis and cardiovascular collapse occurred during the operation. Resuscitation was initiated, but in vain; the patient died. The evolution of clinical events was consistent with a diagnosis of gas embolism. In the investigation of causes, the use of a sapphire tip with the Nd-YAG laser and the cooling of the tip with N2 gas were thought to have contributed to the fatal outcome. The authors warn of the potential risk of gas embolism with the Nd-YAG laser and a coaxial gas cooling system, and they emphasize the importance of monitoring for gas embolism in high-risk patients.

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.

Cardio-cerebrovascular complications from Nd:YAG laser treatment of lung cancer

The laser palliation of patients with unresectable lung cancer has an acceptable complication rate. Perforation, bleeding, and pneumothorax are the main complications described. Cardiovascular morbidity has been reported to be 1% in six surgical series and has been attributed to general anesthetics or hypoxia. However, one very recent anesthesia study described a 25% incidence, and two case reports inferred an air embolism. We reviewed 62 patients who have undergone 111 treatments for endobronchial carcinoma. Eight manifested perioperative cardiac or cerebral events. Five of the eight developed bradycardia; four experienced progression to intraoperative cardiac arrest. Other electrocardiographic abnormalities appeared and resolved within 24 hours. Four patients developed stroke and electrocardiographic changes. Two of these resolved spontaneously within 1 month. Early computed tomography in one patient showed intracerebral air. These data indicate that patient disease or hypoxemia is not sufficient to explain intraoperative cardiac and postoperative cerebral changes. Air embolism to the cerebral circulation occurs during laser bronchoscopy. Reduced cooling air flow, return to helium fiber cooling, or reversion to photodynamic therapy is indicated.