Ultrasound is an imaging modality that has been in clinical use for approximately 50 years. Sokolov first described the potential for using this technology to produce low-resolution images in 1939. Later understanding of the piezoelectric effect and further technological refinements have resulted in machine advancements. We have seen the machine sizes dramatically decrease; some of the earliest machines were the size of refrigerators while recently we have seen the introduction of transducers that are compatible with smartphones. Although ultrasound technology can be utilized in a variety of different settings and body locations, the focus of this article will be on transabdominal ultrasound, its definition, indications and diagnostic pearls and pitfalls.[1][2] Transabdominal ultrasound was initially utilized in its most colloquial setting of pregnancy in the 1960s.[3][4] It is now utilized for visualization of multiple abdominal organs, both intraperitoneal and retroperitoneal. By definition, any evaluation with an ultrasound transducer overlying the abdominal wall can be considered a transabdominal ultrasound. Transabdominal ultrasound can be applied to visualize the liver, gallbladder[5], kidneys, pancreas, small and large intestine, appendix, bladder, uterus, adnexa, spleen, stomach, aorta, and IVC. In the setting of obstetrics and gynecology (OBGYN), the transabdominal approach is usually performed to evaluate for possible pelvic pathology or pregnancy in a less invasive manner. In the emergency department (ED) a transabdominal ultrasound is most commonly utilized to evaluate for intrauterine pregnancy[6], cholelithiasis, intraabdominal free fluid, abdominal aortic aneurysm, and hydronephrosis.  Emergency physicians (EPs) perform a limited point-of-care ultrasound (POCUS) in comparison to formal radiology transabdominal ultrasounds. The EP performs the former compared to the latter, and a trained sonographer performs a thorough and complete examination of the organ. ED POCUS is focused on binary questions that are rapidly evaluated at the bedside and direct patient care immediately. For example: “Is there an intrauterine pregnancy?” In most cases when an intrauterine pregnancy is identified, the examination is complete. While both EPs and sonographers perform a transabdominal ultrasound, the performance characteristics and goals vary.[7]

Medical anti-shock trousers (MAST), also known as military anti-shock trousers or pneumatic anti-shock garments (PASG), are medical devices made of synthetic inflatable air bladders which are applied to a patient’s abdomen, pelvis, and lower extremities.[1] These devices include one abdominal compartment and 2 leg compartments which attach to a pump or inflation unit with valves to control the pressure within each air bladder. The underlying physiologic concept of these devices is simple; apply pressure to the lower extremities to auto-transfuse or shift the patient’s blood volume from the abdomen, pelvis, and lower extremities to the upper body and central circulation. At one time it was also thought these devices increased overall peripheral vascular resistance, halted intraabdominal and lower extremity bleeding, and splinted lower extremity fractures. Medical anti-shock trousers were first described in 1903 by surgeon G.W. Crile as he tried to augment blood pressure with a "pneumatic rubber suit" during neurosurgical procedures. Decades later the term military anti-shock trouser was coined during the Vietnam War where medics applied the device in the field before airlifting soldiers out of a combat zone to a hospital for definitive care.[2][3] Upon conclusion of the Vietnam War in 1975 military surgeons and combat medics returned to the United States and advocated for the use of these devices in pre-hospital and critical care settings. In 1977 the Committee on Trauma for the American College of Surgeons listed MAST as essential devices on all ambulances. Throughout the United States in the late 1970s and 1980s MAST devices were the standard of care for hypotensive trauma patients as evidenced by the American College of Surgeons’ Advanced Trauma Life Support guidelines.[4][5] These devices utilized heavily through the 1980s and as late as 1996 there were 30 states which required MAST devices on all ambulances.[6] These devices were applied in various settings including aviation, combat, pre-hospital and critical care settings. Despite a period of widespread use, MAST devices have been the subject of much debate and research. Initial studies in the 1970s suggested that as much as 20% of a patient's total blood volume was auto-transfused to the upper body by application of the MAST device.[7][8] Further studies performed in the 1980s, however, refuted these early findings, suggesting that only 5% or less of a patient’s overall blood volume was auto-transfused by these devices in both human and dog models.[9][10] During this period there were also studies that showed harmful complications of device use which included compartment syndrome and lower extremity ischemia, amongst others.[11] In 1989, the Houston Fire Department partnered with Ben Taub Hospital to investigate the use of MAST devices in the prehospital environment. This study, which enrolled 201 patients randomized either to MAST application or standard care, did not demonstrate an improvement in mortality rates in penetrating abdominal trauma.[12] Further studies corroborated these findings and could not show a significant difference in the length of hospitalization or intensive care unit stay.[13] Amidst this controversy, the National Association of Emergency Medical Services Physicians published a 1997 position paper citing support for MAST in certain cases including ruptured abdominal aortic aneurysm, pelvic fracture with subsequent hypotension, and severe traumatic hypotension.[14] Of these recommendations, the only high-level evidence, considered Class I, existed for a ruptured abdominal aortic aneurysm.[15] In 2002, a Cochran review demonstrated an increase in intensive care unit length of stay by 1.7 days and concluded there was no evidence to suggest a reduction in mortality from the use of MAST.[5] Given these findings, many hospital systems and EMS agencies gradually abandoned the use of these devices. An article published in the United Kingdom in 1995 suggested that only 1 out of every 5 UK hospitals and 1 out of every 12 UK EMS systems continued to use these devices.[16]

The Ovation stent-graft uncouples the steps of fixation and sealing via a pair of polymer-filled inflatable rings. Apart from the well-documented early results, newer data emerged for mid-term results of Ovation and are presented in this review. Areas covered: Aim of this article was to report all current studies with the mid-term results of the particular endograft, the incidence of complications and failure and discuss their management. Expert Commentary: The Ovation stent-graft exhibits very satisfactory clinical mid-term results in abdominal aortic aneurysms treated within the instructions-for-use. It can also have a very promising role in challenging neck anatomies with conical shape and presence of thrombus or calcification. However, this should be not considered a panacea and long-term results are needed to validate this intriguing aspect.

Thoracic aortic aneurysm (TAA) is a lethal vascular disease that involves localized dilation of the thoracic aorta. The detailed mechanisms of TAA development and rupture are not fully understood. Recent reports have shown that the abnormal appearance of adipocytes in the vascular wall is associated with abdominal aortic aneurysm (AAA) progression or rupture. However, the presence of adipocytes in the TAA wall remains unknown. In this study, we observed the pathology of thoracic aortae to investigate whether adipocytes abnormally appear in the TAA wall. Abnormal appearance of adipocytes was mainly observed in the adventitia in the TAA vascular walls. The adipocyte area in the vascular wall was significantly increased in the TAA wall compared to the control wall. Destruction of collagen fibers, and increase in areas positive for matrix metalloproteinase (MMP) -2, MMP-9, and Mac387+ macrophages were observed in the area around adipocytes in the vascular wall. This study demonstrated the appearance of adipocytes in the TAA wall. The accumulation of adipocytes in AAA wall reportedly facilitates the destruction of fibers surrounding adipocytes, and thereby, leads to vascular wall weakness. Therefore, adipocytes in the TAA wall can be associated with the weakening of the vascular wall as well as the AAA wall. The appropriate control of adipocytes in the vascular wall may prevent weakening of the vascular wall in TAA.