Air Embolism: Diagnosis, Clinical Management and Outcomes

Air embolism is a rare but potentially fatal complication of surgical procedures. Rapid recognition and intervention is critical for reducing morbidity and mortality. We retrospectively characterized our experience with air embolism during medical procedures at a tertiary medical center. Electronic medical records were searched for all cases of air embolism over a 25-year period; relevant medical and imaging records were reviewed. Sixty-seven air embolism cases were identified; the mean age was 59 years (range, 3–89 years). Ninety-four percent occurred in-hospital, of which 77.8% were during an operation/invasive procedure. Vascular access-related procedures (33%) were the most commonly associated with air embolism. Clinical signs and symptoms were related to the location the air embolus; 36 cases to the right heart/pulmonary artery, 21 to the cerebrum, and 10 were attributed to patent foramen ovale (PFO). Twenty-one percent of patients underwent hyperbaric oxygen therapy (HBOT), 7.5% aspiration of the air, and 63% had no sequelae. Mortality rate was 21%; 69% died within 48 hours. Thirteen patients had immediate cardiac arrest where mortality rate was 53.8%, compared to 13.5% (p = 0.0035) in those without. Air emboli were mainly iatrogenic, primarily associated with endovascular procedures. High clinical suspicion and early treatment are critical for survival

Quadrilateral Space Syndrome: Diagnosis and Clinical Management

Quadrilateral space syndrome (QSS) is a rare disorder characterized by axillary nerve and posterior humeral circumflex artery (PHCA) compression within the quadrilateral space. Impingement is most frequently due to trauma, fibrous bands, or hypertrophy of one of the muscular borders. Diagnosis can be complicated by the presence of concurrent traumatic injuries, particularly in athletes. Since many other conditions can mimic QSS, it is often a diagnosis of exclusion. Conservative treatment is often first trialed, including physical exercise modification, physical therapy, and therapeutic massage. In patients unrelieved by conservative measures, surgical decompression of the quadrilateral space may be indicated

Multi-Detector Computed Tomography Imaging Techniques in Arterial Injuries

Cross-sectional imaging has become a critical aspect in the evaluation of arterial injuries. In particular, angiography using computed tomography (CT) is the imaging of choice. A variety of techniques and options are available when evaluating for arterial injuries. Techniques involve contrast bolus, various phases of contrast enhancement, multiplanar reconstruction, volume rendering, and maximum intensity projection. After the images are rendered, a variety of features may be seen that diagnose the injury. This article provides a general overview of the techniques, important findings, and pitfalls in cross sectional imaging of arterial imaging, particularly in relation to computed tomography. In addition, the future directions of computed tomography, including a few techniques in the process of development, is also discussed

Percutaneous Image-Guided Ablation of Lung Tumors

Tumors of the lung, including primary cancer and metastases, are notoriously common and difficult to treat. Although surgical resection of lung lesions is often indicated, many conditions disqualify patients from being surgical candidates. Percutaneous image-guided lung ablation is a relatively new set of techniques that offers a promising treatment option for a variety of lung tumors. Although there have been no clinical trials to definitively compare its efficacy to those of traditional treatments, lung ablation is widely practiced and generally accepted to be safe and effective. Especially encouraging results have recently emerged for cryoablation, one of the newer ablative techniques. This article reviews the indications, techniques, contraindications, and complications of percutaneous image-guided ablation of lung tumors with special attention to cryoablation and its recent developments in protocol optimization

Degree of Left Renal Vein Compression Predicts Nutcracker Syndrome

Nutcracker syndrome (NS) refers to symptomatic compression of the left renal vein (LRV) between the abdominal aorta and superior mesenteric artery with potential symptoms including hematuria, proteinuria, left flank pain, and renal venous hypertension. No consensus diagnostic criteria exist to guide endovascular treatment. We aimed to evaluate the specificity of LRV compression to NS symptoms through a retrospective study including 33 NS and 103 control patients. The size of the patent lumen at point of compression and normal portions of the LRV were measured for all patients. Multiple logistic regression analyses (MLR) assessing impact of compression, body mass index (BMI), age, and gender on the likelihood of each symptom with NS were obtained. NS patients presented most commonly with abdominal pain (72.7%), followed by hematuria (57.6%), proteinuria (39.4%), and left flank pain (30.3%). These symptoms were more commonly seen than in the control group at 10.6, 11.7, 6.8, and 1.9%, respectively. The degree of LRV compression for NS was 74.5% and 25.2% for controls (p < 0.0001). Higher compression led to more hematuria (p < 0.0013), abdominal pain (p < 0.006), and more proteinuria (p < 0.002). Furthermore, the average BMI of NS patients was 21.4 and 27.2 for controls (p < 0.001) and a low BMI led to more abdominal pain (p < 0.005). These results demonstrate a strong correlation between the degree of LRV compression on imaging in diagnosing NS

The Use of Transarterial Approaches in Peripheral Arteriovenous Malformations (AVMs)

Arteriovenous malformations (AVMs) are a subset of congenital vascular malformations (CVMs). They comprise abnormal connections between arterial and venous circulation; treatment approaches are dependent on the angioarchitecture of the AVM, specifically the number and arrangement of the feeder arteries and outflow veins. Various imaging modalities can be used to diagnose and plan treatment. Here we will review the use of transarterial approaches to treat AVMs

Minimally Invasive Limited Ligation Endoluminal-Assisted Revision (MILLER): A Review of the Available Literature and Brief Overview of Alternate Therapies in Dialysis Associated Steal Syndrome

Dialysis associated steal syndrome (DASS) is a relatively rare but debilitating complication of arteriovenous fistulas. While mild symptoms can be observed, if severe symptoms are left untreated, DASS can result in ulcerations and limb threatening ischemia. High-flow with resultant heart failure is another documented complication following dialysis access procedures. Historically, open surgical procedures have been the mainstay of therapy for both DASS as well as high-flow. These procedures included ligation, open surgical banding, distal revascularization-interval ligation, revascularization using distal inflow, and proximal invasion of arterial inflow. While effective, open surgical procedures and general anesthesia are preferably avoided in this high-risk population. Minimally invasive limited ligation endoluminal-assisted revision (MILLER) offers both a precise as well as a minimally invasive approach to treating both dialysis associated steal syndrome as well as high-flow with resultant heart failure. MILLER is not ideal for all DASS patients, particularly those with low-flow fistulas. We aim to briefly describe the open surgical therapies as well as review both the technical aspects of the MILLER procedure and the available literature