Heart function after injection of small air bubbles in coronary artery of pigs

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.

Systemic arterial gas embolism (SAGE) as a complication of bronchoscopic lung biopsy: a case report and systematic literature review

Background

Systemic arterial gas embolism (SAGE) is a rare yet serious and underrecognized complication of bronchoscopic procedures. A recent case of presumed SAGE after transbronchial needle aspiration prompted a systematic literature review of SAGE after biopsy procedures during flexible bronchoscopy.

Methods

We performed a systematic database search for case reports and case series pertaining to SAGE after bronchoscopic lung biopsy; reports or series involving only bronchoscopic laser therapy or argon plasma coagulation (APC) were excluded. Patient data were extracted directly from published reports.

Results

A total of 29 unique patient reports were assessed for patient demographics, specifics of the procedure, clinical manifestations, diagnostic findings, and clinical outcomes. Cases of SAGE occurred after multiple types of bronchoscopic biopsy and under both positive and negative pressure ventilation. The most common clinical findings were neurologic, followed by cardiac manifestations; temporal patterns included acute onset of cardiac or neurologic emergencies immediately after biopsy, or delayed awakening post-procedure. There was a high mortality rate among cases (28%), with residual neurologic deficits also common (24%).

Discussion

SAGE is an underrecognized but severe adverse effect of bronchoscopic lung biopsy, which often presents with acute coronary or cerebral ischemia or delayed awakening from sedation. It is important for all physicians who perform bronchoscopic biopsies to be aware of the clinical manifestations and therapeutic management of SAGE in order to mitigate morbidity and mortality among patients undergoing these procedures.

Preparation of PCI Balloons: What Is the Best Method to Avoid Air in the Balloon? A Comparison of Different Methods of Connecting PCI Balloons and the Inflation Syringe while Removing Air from the Balloon

As the techniques to connect percutaneous coronary intervention (PCI) balloons and the inflation syringe vary in the instructions for use and in practice, we measured the amount of air in PCI balloons after testing three connection methods to an inflation syringe. Following the preparation using one of the three methods, 114 balloons and stent balloons were tested four times. Method 1 connected the syringe and the balloon catheter directly after purging and filling the lumen, while method 3 omitted the purging and filling process. With method 2, the catheter lumen was purged, filled and fully vented via a three-way valve. The primary endpoint answered whether air remained in the balloon, and if so, the secondary endpoint indicated the total volume of remaining air. The connection with a three-way valve achieved significantly less air in the inflated balloon as compared with either direct connection approach (27% vs. 44% and 51%; p = 0.015). For the direct connection, no significant difference between purging and filling the lumen prior to making the connection or not existed. According to these findings, the best method to connect a PCI balloon to the inflation syringe while removing air involves using a three-way valve.

Lethal coronary air embolism caused by the removal of a double-lumen hemodialysis catheter: a case report

Coronary air embolism is a rare event. We report a case in which an acute myocardial infarction occurred in the region supplied by the right coronary artery after the removal of a double-lumen hemodialysis catheter. Emergent coronary angiography revealed air bubbles obstructing the mid-segment of the right coronary artery with slow flow phenomenon distally. The patient expired due to myocardial infarction.

Multiple Air Embolism During Coronary Angiography: How Do We Deal With It?

Coronary air embolism remains a serious complication of cardiac catheterization despite careful prevention. The complications of coronary air embolism range from clinically insignificant events to acute coronary syndrome, cardiogenic shock, and death. We report here a case of multiple air emboli in both left coronary arteries, complicated by cardiogenic shock and ventricular fibrillation in a 49-year-old male patient undergoing elective percutaneous coronary intervention. The patient recovered after supportive measures, including oxygen, intravenous dopamine infusion, and cardiac compression, and repeated forceful injection of heparinized saline successfully resolved the air emboli. He then eventually underwent successful percutaneous coronary intervention in the left anterior descending artery without any residual stenosis.

Vettath's blower and blower/mister - a simple device for OPCAB surgery

Since the advent of off-pump coronary artery bypass surgery, a blower/mister has been routinely used in cardiac operation theatres. In our setup, in an attempt to reduce the cost of coronary artery bypass grafting by performing off-pump coronary artery bypass, reusable materials have been routinely used.

HBO and gas embolism

Gas embolism, which occurs with the entry of gas into the circulatory system from the vein, artery or both, is a potentially serious even fatal condition. The two main causes of gas embolism are iatrogenic and diving. The site of entry and the signs and symptoms distinguish between arterial and venous embolism. The entering gas may be air, but may also be CO(2) or other gases, especially in iatrogenic embolism. Supportive care is the primary therapy for venous gas embolism, while hyperbaric oxygen therapy in addition to supportive care is the first line of treatment for arterial gas embolism. In this article, we will review the pathophysiology, etiology, diagnosis and treatment of gas embolism.

Coronary air embolism: A case report and review of the literature

Coronary air embolism is a complication in the catheterization laboratory that can be associated with high morbidity and even mortality. A case report of air embolism and methods to prevent this complication from occurring are presented along with various management techniques.

Gas embolism: pathophysiology and treatment

Based on a literature search, an overview is presented of the pathophysiology of venous and arterial gas embolism in the experimental and clinical environment, as well as the relevance and aims of diagnostics and treatment of gas embolism. The review starts with a few historical observations and then addresses venous air embolism by discussing pulmonary vascular filtration, entrapment, and the clinical occurrence of venous air emboli. The section on arterial gas embolism deals with the main mechanisms involved, coronary and cerebral air embolism (CAE), and the effects of bubbles on the blood-brain barrier. The diagnosis of CAE uses various techniques including ultrasound, perioperative monitoring, computed tomography, brain magnetic resonance imaging and other modalities. The section on therapy starts by addressing the primary treatment goals and the roles of adequate oxygenation and ventilation. Then the rationale for hyperbaric oxygen as a therapy for CAE based on its physiological mode of action is discussed, as well as some aspects of adjuvant drug therapy. A few animal studies are presented, which emphasize the importance of the timing of therapy, and the outcome of patients with air embolism (including clinical patients, divers and submariners) is described.

Successful resuscitation of patient with massive coronary air embolism occluding two vessels during coronary angiography--a case report

Massive coronary air embolism is usually disastrous although successful resuscitation has been reported previously. To what extent a patient with coronary air embolism can be resuscitated is not known. The authors report a rare case of massive air embolism to the left coronary arteries and successful resuscitation by vigilantly maintaining an effective driving force to dissipate the air lock.

Successful management of right coronary air embolus after intracoronary administration of verapamil

A case of a 50 year-old male with a coronary air embolism is described. The case was successfully treated with intracoronary administration of verapamil.

Cardiac depression after experimental air embolism in pigs: role of addition of a surface-active agent

OBJECTIVE

Air bubbles entering the coronary artery may have harmful effects on cardiac function. From the physical point of view it is the relatively high surface tension of the blood-air interface which causes bubbles to trap in small vessels. The aim of the present study was to reduce depression of myocardial function from air embolism by lowering the surface tension of air bubbles.

METHODS

The effect of using antifoam as a surface-tension-reducing agent on air bubble entrapment and cardiac function was investigated in 6 anesthetized pigs (27 +/- 1 kg) and analyzed using a two-compartment diffusion model. Air bubbles with a diameter of 150 microns were selectively injected into the left anterior descending coronary artery (LADCA) in a carrying fluid in the presence or absence of antifoam. Myocardial systolic segment shortening in the LADCA region (SS-LADCA) was measured by sonomicrometry. Presence of emboli was detected by measuring the amount of reverberation of ultrasound scattered by trapped air bubbles.

RESULTS

SS-LADCA transiently decreased after injections of air bubbles in both the absence and presence of antifoam. However, in the presence of antifoam the regional depression recovered to normal sooner, the average depth of the depression was reduced, and bubbles from the embolized area cleared faster. These observations can be explained by a model derived from Laplace's law.

Retrograde cardioplegia preserves myocardial function after induced coronary air embolism

Coronary air embolism is a potential complication of cardiopulmonary bypass. We compared left ventricular function before and after the administration of antegrade or retrograde cardioplegic solution in a porcine model of coronary air embolism. Nineteen pigs were placed on cardiopulmonary bypass support and cooled to 32 degrees C. The heart was initially arrested with antegrade cold blood cardioplegic solution. The aortic crossclamp was released at 30 minutes and 0.02 cc/kg body weight of air was injected into the left anterior descending artery distal to the first diagonal branch. After 5 minutes the aorta was reclamped and the animals treated with 15 ml/kg body weight of 1:4 blood cardioplegic solution delivered by the antegrade (n = 6) or retrograde (n = 7) method. Control animals (n = 6) were not treated. Changes in regional preload recruitable stroke work were used to assess left ventricular performance before and after cardiopulmonary bypass. Two control animals could not be weaned from cardiopulmonary bypass. Left ventricular function was best preserved after treatment of induced coronary air embolism with retrograde cardioplegia (90% of baseline). Coronary air embolism treatment with antegrade cardioplegia resulted in diminished left ventricular performance (68% of baseline). In control animals left ventricular contractility was significantly impaired (39% of baseline). We conclude that administration of retrograde cardioplegic solution may be an effective method of treating coronary air embolism. The favorable outcome seen with cardioplegia may be in part because of its ability to protect the ischemic myocardium while the solution mechanically dislodges air from the vascular bed.

Coronary air embolism: incidence, severity, and suggested approaches to treatment

Because no well-controlled study of inadvertent coronary air embolism has been done to truly quantify the incidence of this cardiac catheterization complication, we wanted to determine its incidence and severity in an active teaching medical center and assess approaches to treatment. We retrospectively reviewed 3,715 coronary angiogram and PTCA reports performed over 32 months. Further, we classified severity based on angiographic findings and symptoms as minimal, mild, moderate, and massive. Two independent angiographers reviewed 764 consecutive cines performed in the first 2 months of training of each new fellow and 740 cines performed in the last 2 months of training. We found that during the first 2 months of training the overall incidence for significant intracoronary air embolism was 0.19% (7 documented cases) compared with 0.2% (3 cases) for non-reported, minimal asymptomatic air embolism. The estimated incidence for total air emboli events was 0.27% (10/3,715). We did not find coronary air emboli in the 740 cines performed at the end of fellowship training. Additionally, the incidence of coronary air emboli during PTCA training was much higher compared with coronary angiography training (0.84 vs. 0.24%). Although there is no best technique to restore blood flow after blockage by air emboli, we suggest as options aspirating the air or forcefully injecting saline, with auxiliary supportive measures like 100% oxygen, IABP, CPR, and DC cardioversion.