Foreword

Worldwide, there are nearly 250 million major surgical procedures performed annually. Despite generally excellent outcomes, associated health complications and consequences to individuals and health systems are significant. Within the overall subset of morbidity, embolic diseases feature very prominently. Such events range from the arterial to the venous emboli, from preoperative "incidental" findings to postoperative acute emergencies.

Embolic phenomena (EP) are known to affect key anatomical structures, from the brain to the heart, and can be present in a variety of settings, from pregnancy to war. In essence, emboli can be characterized as "non-stop concerns" and "sources of fear" for lay people and physicians alike. An embolism may be defined as the intravascular lodging of an embolus or vascular blockage-causing fragment, but it is not only that. An embolus is more than a fragment, it is a life-changing event for individuals and their families, and an economic burden to institutions, communities, industry, and governments. It is a round of biological consequences shot through society by Mother Nature. Consequently, the healthcare practitioner must not only be aware of diagnosis and treatment, but also understand the true global impact of EP from the perspectives of an individual patient, the health system, and the greater community.

My experiences in intensive care units run the gamut from very small institutions to well-recognized major medical centers, as well as those not only in the United States, but also in China, India, and Europe. I have also had the opportunity to participate in many local, national, and global public health efforts regarding community health problems and challenges, and while physicians and other healthcare providers may view emboli and embolism as a medical entity, they are also a public health problem with significant consequences. The authors of this text wish for you to know the nature and impact of emboli, and while the subject cannot be covered in its entirety from every aspect, the reader will be left better educated and with an indelible impression of the enormity of the problem.

This book provides a sampling of many of the problems encountered by healthcare providers in their day-to-day practice of medicine in regard to emboli. The overview provided by this text will be most valuable to those experienced in the care of patients as well as novices. The topics covered are of consequence to those in primary care as well as those who practice in the acute care or intensive care environments. The editors of this book have had considerable experience and involvement with the topics addressed, and have dedicated their professional lives to the care of the critically ill patient. Their choice of topics is to provide the healthcare provider with an overview of wide-ranging clinical situations to equip you, the reader, with tools to help the patient, and for you to better understand the ramifications of this pathology to society in general.

**II**

**Chapter 9 149**

Bullet and Shrapnel Embolism: When "Uncommon" Meets "Dangerous" *by Stephen D. Dingley, Zachary E. Darby, Jennifer C.B. Irick, Gregory Domer* 

*and Stanislaw P. Stawicki*

It is my hope that the examples provided to the reader in this important book will provide a solid clinical foundation in some of the vascular diagnoses that plague our patients, both in and out of the intensive care unit, and in the perioperative period. I commend the editors and individual chapter authors on their effort and product, and I believe that these materials will enhance patient care and outcomes, and expectantly assist in lessening the burden to families and the community.

> Respectfully submitted, **Thomas J. Papadimos, MD, MPH, FCCM, FAIM** Professor, Division of Critical Care Department of Anesthesiology The Ohio State University Wexner Medical Center Columbus, Ohio, USA

Preface

An embolism is defined as the intravascular lodging of an *embolus* or a *vascular blockage-causing fragment*. Emboli are a diverse group of pathological objects that travel within blood vessels, including blood clots or thromboemboli, air bubbles or *aeroembolism*, fat globules, infected particles or *septic emboli*, amniotic fluid or *amniotic emboli*, iatrogenically introduced foreign material like a catheter or wire fragments, and even bullet fragments and shrapnel. The most dreaded complication of an embolus is either partial or total blockage of blood flow distal to the site of embolization. This risk is inherent to the process of intravascular embolus migration, and can be controlled or limited only in cases where proper risk assessment based on known predisposing factors—has been completed and appropriate therapeutic steps (e.g., anticoagulation, treatment of endocarditis) implemented.

Distal embolization can lead to limb, organ, and life-threatening sequelae of end-organ dysfunction, tissue ischemia, and potential necrosis. In cases of fat or amniotic fluid embolism, associated neurological sequelae may be devastating and severe. In fact, as a marker of the severity and complexity of the clinical problem, even in the absence of obvious neurologic findings, patients who present with a source of embolism, such as an intracardiac mass, often benefit from neurological imaging since many patients may have subclinical or *silent* strokes—a key clinical finding, critical in medical decision making, treatment, and risk stratification.

Although heterogeneous in their genesis, emboli often constitute a manifestation of other, concurrent pathological processes. For example, fat emboli are associated with long-bone fractures and surgical fixation. In another typical example, venous emboli may begin in the setting of trauma, malignancy, or various other hypercoagulable states. Arterial emboli, secondary to untreated atrial fibrillation, constitute a common emergency, leading to cerebrovascular infarcts and bowel and acute limb ischemia. Less common, but not less concerning, are left ventricular clots, often resulting from apical wall-motion abnormalities related to a previous myocardial

Septic emboli originate from a variety of infectious foci, including endocarditis, prosthetic implants, soft tissue infections, and abscesses. If not recognized promptly, affected patients can suffer devastating systemic and neurological sequelae. Air emboli are most often iatrogenically induced. Due to their rarity, providers who are more likely to encounter air emboli in their practices must remain vigilant whenever in a situation prone to these uncommon phenomena. Foreign body emboli, whether iatrogenic or traumatic, constitute an acquired group of conditions. A phenomenon that is becoming better understood is the concept of a *paradoxical* embolism in which a venous source, such as a deep vein thrombosis, migrates across an intracardiac shunt or arteriovenous malformation and enters into the systemic, arterial, circulation. As such, whenever cases of paradoxical embolism are encountered, a search for venous-to-arterial shunting should be pursued and factored into the next steps. Finally, amniotic fluid embolism—one of the most devastating and poorly understood embolic phenomena—continues to be

infarction, which may present in a similar fashion.
