Severe pulmonary oedema after venous air embolism

Iatrogenic air embolism: pathoanatomy, thromboinflammation, endotheliopathy, and therapies

Iatrogenic vascular air embolism is a relatively infrequent event but is associated with significant morbidity and mortality. These emboli can arise in many clinical settings such as neurosurgery, cardiac surgery, and liver transplantation, but more recently, endoscopy, hemodialysis, thoracentesis, tissue biopsy, angiography, and central and peripheral venous access and removal have overtaken surgery and trauma as significant causes of vascular air embolism. The true incidence may be greater since many of these air emboli are asymptomatic and frequently go undiagnosed or unreported. Due to the rarity of vascular air embolism and because of the many manifestations, diagnoses can be difficult and require immediate therapeutic intervention. An iatrogenic air embolism can result in both venous and arterial emboli whose anatomic locations dictate the clinical course. Most clinically significant iatrogenic air emboli are caused by arterial obstruction of small vessels because the pulmonary gas exchange filters the more frequent, smaller volume bubbles that gain access to the venous circulation. However, there is a subset of patients with venous air emboli caused by larger volumes of air who present with more protean manifestations. There have been significant gains in the understanding of the interactions of fluid dynamics, hemostasis, and inflammation caused by air emboli due to in vitro and in vivo studies on flow dynamics of bubbles in small vessels. Intensive research regarding the thromboinflammatory changes at the level of the endothelium has been described recently. The obstruction of vessels by air emboli causes immediate pathoanatomic and immunologic and thromboinflammatory responses at the level of the endothelium. In this review, we describe those immunologic and thromboinflammatory responses at the level of the endothelium as well as evaluate traditional and novel forms of therapy for this rare and often unrecognized clinical condition.

[Sitting position in neurosurgery: realizing the risks]

The author discusses potential intraoperative complications following neurosurgical interventions in sitting position: venous air embolism and paradoxical air embolism, postural hypotension, pneumocephalus, cervical flexion neuropathy, positional damage to peripheral nerves and others. Naturally, prevention of these complications is also considered, and the most effective approach is surgery in lying position.

Anaesthesia for Neurosurgery in the Sitting Position: A Practical Approach

Neurosurgery in the sitting position offers advantages for certain operations. However, the approach is associated with potential complications, in particular venous air embolism. As the venous pressure at wound level is usually negative, air can be entrained. This air may follow any of four pathways. Most commonly it passes through the right heart into the pulmonary circulation, diffuses through the alveolar-capillary membrane and appears in expelled gas. It may pass through a pulmonary-systemic shunt such as a probe patent foramen ovale (paradoxical air embolism); it may collect at the superior vena cava-right atrial junction. Rarely it may traverse through lung capillaries into the systemic circulation. Many monitors, such as the precordial Doppler, capnography, pulmonary artery catheter, transoesophageal echocardiography are useful for venous air embolism detection, with transoesophageal echocardiography being today's gold standard. Various manoeuvres, including neck compression and volume loading, are also useful in reducing the incidence of venous air embolism. Volume loading, in particular, is very helpful as it reduces the risk of hypotension. Other particular concerns to the anaesthetist are airway management, avoidance of pressure injuries, and the risk of pneumocephalus, oral trauma, and quadriplegia. Newer anaesthetic agents have made the choice of anaesthetic technique easier. An appreciation of the implications of neurosurgery in the sitting position can make the procedure safer.

Acute pulmonary edema and thrombocytopenia following venous air embolism during sitting position neurosurgery

Venous air embolism (VAE) is a well-known complication of sitting position neurosurgery which most characteristically manifests as mild to severe hemodynamic alterations. Development of pulmonary edema is a known, though infrequent, manifestation of VAE. We report here the occurrence of acute pulmonary edema without accompanying hemodynamic changes in a patient undergoing retromastoid craniotomy and tumor decompression in the sitting position. The patient required supportive treatment and elective ventilation for 11 days before the edema resolved. He also developed significant postoperative thrombocytopenia which though, was self-limiting. Thus, VAE may manifest with atypical manifestations like pulmonary edema and thrombocytopenia that can significantly contribute to postoperative patient morbidity.

Massive gas embolism revealed by two consecutive postmortem computed-tomography examinations

We present a case of unusual gas embolism in a 73-year-old man who was found in a state of cardiopulmonary arrest with an oxygen-supply tube connected to an intravenous catheter inserted into his median cubital vein. Postmortem computed tomography (PMCT) performed 27 h after death showed systemic gas distribution including intravascular gas, pneumothorax, pneumoperitoneum, pneumomediastinum, pneumoretroperitoneum and gastric emphysema. A second PMCT scan performed 116 h after death showed a marked decrease of air inside the body. The current case shows the importance of PMCT for visualization, quantification, and preservation of evidence for establishment of the cause of death in cases with suspected gas embolism. Our findings also indicate that performance of two PMCT examinations may be useful for differentiation of embolized gas from gas produced by putrefaction.

Pulmonary edema after catastrophic carbon dioxide embolism during laparoscopic ovarian cystectomy

Laparoscopy is a surgical procedure used both for diagnosis and for various treatments. A rare but sometimes fatal complication of laparoscopy is pulmonary embolism with CO2 resulting in pulmonary edema. During laparoscopic gynecological surgery in a 29-year-old woman who had previously undergone lower abdominal surgery, the end-tidal CO2 suddenly increased from 40 mmHg to 85 mmHg and then decreased to 13 mmHg with hemodynamic deterioration. These events are characteristic of a CO2 embolism. When this occurred, CO2 insufflation was immediately stopped and the patient was resuscitated. The patient's condition gradually improved with aggressive treatment, but the clinical course was complicated by bilateral pulmonary edema. This case of pulmonary edema was soon resolved with supportive management. The formation of a CO2 embolism during laparoscopy must be suspected whenever there is a sudden change in the end-tidal CO2. In addition, the possibility of pulmonary edema should be considered when a CO2 embolism occurs.

[Lesional pulmonary oedema following laparoscopy for haemorrhage: aetiological assessment and possible gas embolism]

A 44-year-old woman had to undergo repeat laparoscopy, four hours after laparoscopic sigmoidectomy, because of persistent bleeding from the drain. The bleeding caused perioperative shock and necessitated transfusional support. The following day she developed dyspnea, revealing pulmonary oedema. As her respiratory status continued to deteriorate and the bleeding persisted, she was transferred to the intensive care unit on day 2, after corrective laparotomy. The echocardiogram ruled out cardiogenic pulmonary oedema. No inhalation had occurred during the three anaesthetic procedures, and onset several hours after transfusion argued against lesional pulmonary oedema secondary to packed red cell transfusion. Given the context of repeat surgery by laparoscopy because of active bleeding, a diagnosis of lesional pulmonary oedema complicating CO(2) embolism was made. She received symptomatic treatment and her respiratory status gradually improved. Four months later her clinical status was normal. The different causes of postoperative pulmonary oedema and the pathophysiologic mechanisms of pulmonary lesions induced by gas embolism are discussed.

Repeated attacks of venous air embolism during endoscopic sinus tumor surgery: a case report

Repeated attacks of venous air embolism during an operation is a very rare situation. We report a case of multiple venous air emboli during an endoscopic surgery of a sphenoidal sinus tumor.

Large venous air embolism in the sitting position despite monitoring with transoesophageal echocardiography

A 49-year-old male with neurofibromatosis type II was scheduled for posterior fossa craniotomy and excision of a right acoustic neuroma and placement of an auditory brainstem implant in the sitting position. Intra-operatively, the patient was monitored with transoesophageal echocardiography which detected two major episodes of venous air embolism. Despite immediate treatment the patient's gas exchange progressively worsened during surgery and a chest X-ray showed extensive bilateral pulmonary infiltrates. The patient developed acute respiratory distress syndrome and required inotropic support in the intensive care unit. Although transoesophageal echocardiography allowed rapid detection of venous air embolism, there was no evidence of therapeutic benefit.

Venous air embolism during awake craniotomy in a supine patient

PURPOSE

To report a non-fatal case of intraoperative venous air embolism (VAE) during an awake craniotomy. VAE presented with unusual clinical features.

CLINICAL FEATURES

VAE during an awake craniotomy has not been reported frequently. The patient we describe presented with persistent coughing followed by tachypnea, hypoxia and reduction in end-tidal CO(2) during dural opening while undergoing an awake craniotomy in the supine position. Cardiovascular variables were stable during the episode except for transient hypertension. Having ruled out airway obstruction and low cardiac output, we concluded that air embolism was the cause. The patient responded immediately to the standard treatment of air embolism and recovered without any complication.

CONCLUSION

This case illustrates a VAE during an awake craniotomy and emphasizes the importance of early diagnosis in the management.

Acute pulmonary edema after low-level air embolism during craniotomy. Case report

Acute pulmonary edema after a large air embolus occurring during neurosurgery is a recognized phenomenon. The authors describe the course of a 76-year-old man who presented with noncardiogenic pulmonary edema shortly after undergoing resection of a high convexity meningioma. Transthoracic Doppler sonography, however, showed no evidence of a large intraoperative emboli; the evidence for ongoing but low-magnitude air embolus included visualization of bone aspiration of irrigant before bone-edge waxing, transient intraoperative declines in end-tidal CO2 tension, and an increase of the fraction of inspired oxygen to maintain adequate saturation after removal of the craniotomy flap. There was no hemodynamic instability noted. The airspace disease was self-limited and resolved on supportive treatment after approximately 1 week, as would be expected for pulmonary edema caused by a single large intravenous air embolus. The authors present this case as the first report of pulmonary edema resulting from low-level air embolus occurring during craniotomy. This situation may go unrecognized intraoperatively but can cause the same significant postoperative morbidity as larger, more easily identified air emboli.

Air embolism during awake craniotomy

A case of venous air embolism during awake craniotomy is described. Chest pain and electrocardiographic changes were the major presenting features. Capnography detected a decrease in end-tidal carbon dioxide and demonstrates its use as an aid in the diagnosis of air embolism in the awake patient. Following this episode persistent hypoxaemia developed secondary to acute pulmonary oedema and a pleural effusion.