A study of the role of percutaneous catheter drainage in the management of acute severe pancreatitis

BACKGROUND AND OBJECTIVES: The treatment of acute pancreatitis is not disease-specific, targeting underlying pathophysiology. Initial life-saving measures include fluid resuscitation and supportive therapy to various organ systems which mitigates the concomitant course of the disease process thereby decreasing the severity of acute pancreatitis. There has been a paradigm shift in the treatment protocols of acute pancreatitis over the past two decades which has shifted from an early aggressive surgical treatment to a more conservative strategy. Interventional treatment is seldom needed in majority of the patients with acute pancreatitis. However, interventional treatment in the form of percutaneous catheter drainage, open or minimally invasive endoscopic necrosectomy is indispensable in certain conditions of severe acute pancreatitis. In this study, we assess the role of image guided percutaneous catheter drainage of peri-pancreatic fluid and necrotic collections in the management protocols of severe acute pancreatitis. We analyze the outcome of patients with severe acute pancreatitis managed by conservative treatment, percutaneous catheter drainage and surgical necrosectomy. We also compare the role of each management strategy in sterile and infected necrotic pancreatitis Finally, we study the pros and cons of different treatment groups with particular emphasis on the benefits of percutaneous catheter drainage TYPE OF STUDY: Observational (prospective) study. METHODOLOGY: On admission, all the cases were resuscitated with intravenous fluids, organ dysfunction management, analgesics and antibiotics such as imipenem/cilastatin or meropenem and metronidazole administered prophylactically. Within three days of admission, early nutritional resuscitation was taken care of. The enteral feeding route, whether per-oral, nasogastric or nasojejunal was decided by the performance status of the individual. In accordance with the culture and sensitivity of the drain fluid or blood and urine samples, appropriate antibiotics was administered. Continuous monitoring of all the cases were done round the clock to watch out for potentially life threatening complications like multi organ dysfunction and septicemia. Radiological diagnosis using usg of abdomen and/or CT was done in a periodic manner to help assess the localization or the spread of inflammatory collections and the development and delineation of necrosis. Supportive treatment was offered to those individuals who showed improvement when compared with their status during admission. Those cases who developed (i) contaminated peripancreatic collections (ii) sterile but symptomatic (abdominal hypertension or compartment syndrome) collections (iii) infected necrosis, (iv) progressive organ dysfunction underwent image-guided PCD or surgical necrosectomy. In cases with 5cm or greater collections, demonstrating unrelenting hyperthermia, elevated leucocytes and progressive organ dysfunction, an USG or CT-guided PCD was performed using a 12 Fr pigtail catheter by the Seldinger technique via the transperitoneal or retroperitoneal route avoiding injury to the bowel and other vital structures. This technique was preceded by Vit. K, FFP and platelet supplementation to treat coagulopathy, when required. PCD was anchored to drain by gravity and NS irrigation was performed when solid necrotic debris was drained or it caused blockage of the tube. Periodic ultrasonogram abdomen was performed to verify the emptying of the collections and the requirement to flush the tube and reposition the same. Periodic contrast enhanced CT scans were done, if need be, to monitor the resolution or the progression of the disease process and the requirement for surgical necrosectomy. If the drain quantity was lower than ten milliliter for 2 days, the PCD was removed under ultrasound guidance. PCD success was defined when there was reduction in the size of the fluid collections, control of septicemia and absence of requirement of surgery. Surgery was performed if there was no clinical improvement, worsening organ failure in spite of PCD or when the individuals exhibited Warshaw’s theory of un-wellness. The surgery included open necrosectomy and a irrigation and drainage of the lesser sac. The timing of the surgical treatment, no. of days of SICU care, duration of in-patient treatment and case fatality rates were noted RESULTS: PCD was used successfully in 18 (51.4%) of the total 35 cases. Of the 18 patients, 15 (42.9) patients recovered without the need for surgical management and it helped in delaying the morbidity of upfront surgery in 2 (11.1%) patients. The complications of PCD include introduction of infection, bleeding, perforation of the hollow viscus or other vital structures and slippage of the catheter. Bleeding is a rare event except in patients with coagulopathy (as indicated by an elevated PT/INR) and is usually due to the disease process itself rather than PCD therapy. Arterial pseudo-aneurysms is treated by arterial embolization whereas venous bleeding is rarely catastrophic. Fistulization of the hollow viscus could be due to an inadvertent bowel injury during catheter insertion but is more commonly due to the spread of peri-pancreatic inflammation. Catheter slippage occurred in 2(11.1%) of our patients and image guided repositioning was all that was required to tackle this complication. CONCLUSION: Modern treatment algorithms of SAP involves the so-called ‘‘step-up’’ approach where percutaneous catheter drainage serves as a primary stabilizing measure and is often regarded as a temporizing method to tackle septicemia and prolong surgery free interval. The next step is the minimal access necrosectomy or the traditional open necrosectomy. That said, in well selected patients, PCD with appropriate caliber drains and supplementary therapy is all that is required or it acts as a bridge to a delayed necrosectomy which significantly has a low morbidity and mortality when compared to an early surgery

Using EBSD and TEM-Kikuchi patterns to study local crystallography at the domain boundaries of lead zirconate titanate

Reliable EBSD mapping of 90° domains in a tetragonal ferroelectric perovskite has been achieved for the first time, together with reliable automated orientation determination from TEM-Kikuchi patterns. This has been used to determine misorientation angles at 90° domain boundaries and thus local <i>c</i>/<i>a</i> ratios. The sources of orientation noise/error and their effects on the misorientation angle data have been thoroughly analyzed and it is found that this gives a cosine distribution of misorientation angles about the mean with a characteristic width related to the width of the orientation noise distribution. In most cases, a good agreement is found between local <i>c</i>/<i>a</i> ratios and global measurements by X-ray diffraction, but some clear discrepancies have also been found suggesting that real local variations are present, perhaps as a consequence of compositional inhomogeneities

Post-traumatic osteoarthritis in mice following mechanical injury to the synovial joint

We investigated the spectrum of lesions characteristic of post-traumatic osteoarthritis (PTOA) across the knee joint in response to mechanical injury. We hypothesized that alteration in knee joint stability in mice reproduces molecular and structural features of PTOA that would suggest potential therapeutic targets in humans. The right knees of eight-week old male mice from two recombinant inbred lines (LGXSM-6 and LGXSM-33) were subjected to axial tibial compression. Three separate loading magnitudes were applied: 6N, 9N, and 12N. Left knees served as non-loaded controls. Mice were sacrificed at 5, 9, 14, 28, and 56 days post-loading and whole knee joint changes were assessed by histology, immunostaining, micro-CT, and magnetic resonance imaging. We observed that tibial compression disrupted joint stability by rupturing the anterior cruciate ligament (except for 6N) and instigated a cascade of temporal and topographical features of PTOA. These features included cartilage extracellular matrix loss without proteoglycan replacement, chondrocyte apoptosis at day 5, synovitis present at day 14, osteophytes, ectopic calcification, and meniscus pathology. These findings provide a plausible model and a whole-joint approach for how joint injury in humans leads to PTOA. Chondrocyte apoptosis, synovitis, and ectopic calcification appear to be targets for potential therapeutic intervention

Strong plasmonic fluorescence enhancement of individual plant light-harvesting complexes

Plasmonic coupling of metallic nanoparticles and adjacent pigments can dramatically increase the brightness of the pigments due to the enhanced local electric field. Here, we demonstrate that the fluorescence brightness of a single plant light-harvesting complex (LHCII) can be significantly enhanced when coupled to single gold nanorods (AuNRs). The AuNRs utilized in this study were prepared via chemical reactions, and the hybrid system was constructed using a simple and economical spin-assisted layer-by-layer technique. Enhancement of fluorescence brightness of up to 240-fold was observed, accompanied by a 109-fold decrease in the average (amplitude-weighted) fluorescence lifetime from approximately 3.5 ns down to 32 ps, corresponding to an excitation enhancement of 63-fold and emission enhancement of up to 3.8-fold. This large enhancement is due to the strong spectral overlap of the longitudinal localized surface plasmon resonance of the utilized AuNRs and the absorption or emission bands of LHCII. This study provides an inexpensive strategy to explore the fluorescence dynamics of weakly emitting photosynthetic light-harvesting complexes at the single molecule level.Comment: 23 pages, 6 figures, 2 supplementary figures, and supplementary equation

A global mental health fund for serious mental illness in low-income and middle-income countries.

Serious Mental Illnesses (SMI) are psychiatric disorders (excluding developmental and substance use disorders) that result in considerable functional impairment. These conditions receive little or no funding in most Low and Middle Income (LAMI) countries. The huge gap in resources for SMI can only be met by a global fund to provide the treatment of SMI in LAMI countries. The Global Fund to fight AIDS established more than two decades ago, not only provided enormous funding but most importantly, generated the hope that the condition could be treated. We argue that SMI stand today where HIV-AIDS was a couple of decades ago. The cost effective interventions for these disorders are available. For example, it is estimated that that an extra 11 Naira or I$ 0.27 per capita would need to be invested each year to increase the present treatment coverage for schizophrenia of 20% to a level of 70% in Nigeria. The treatment package should include free access to essential medicines to treat psychotic disorders and a component of appropriate evidence based psychosocial intervention, which have been evaluated in number of studies in these countries. It is ethical and public health imperative that a Global Fund to provide the basic treatment for those suffering from SMI is established and the seed money for the proposed fund should be provided by rapidly developing LAMI countries such as India and South Africa

Corneoscleral laceration and ocular burns caused by electronic cigarette explosions

PURPOSE: To report cases of acute globe rupture and bilateral corneal burns from electronic cigarette (EC) explosions. METHODS: Case series. RESULTS: We describe a series of patients with corneal injury caused by EC explosions. Both patients suffered bilateral corneal burns and decreased visual acuity, and one patient sustained a unilateral corneoscleral laceration with prolapsed iris tissue and hyphema. A review of the scientific literature revealed no prior reported cases of ocular injury secondary to EC explosions; however, multiple media and government agency articles describe fires and explosions involving ECs, including at least 4 with ocular injuries. CONCLUSIONS: Given these cases and the number of recent media reports, ECs pose a significant public health risk. Users should be warned regarding the possibility of severe injury, including sight-threatening ocular injuries ranging from corneal burns to full-thickness corneoscleral laceration

Research challenges in 5G networks: a HetNets perspective

This paper highlights use cases, emerging machine type communication (MTC) technologies, ongoing research activities, and existing research challenges in 5G networks. 5G networks are faced with the following challenges: (i) handling large amounts of data, (ii) coping with different types of data traffic, i.e., human-type, machine-type, and combined-type (iii) connecting billions of machines, and (iv) severe resource limitations of devices. The ubiquitous nature of cellular networks make them the preferred choice for access networks, but a lack of communication resources is a problem. To address the resource scarcity issue, different wireless access networks may combine to form a heterogeneous network (HetNet) and hence become a single 5G network. For long-term success of 5G networks, we envision the following as important research outputs: (i) a scalable 5G network architecture that can handle a large number of human users and machines considering different constraints, (ii) a comprehensive quality of service (QoS) framework to satisfy heterogeneous users and machines requirements, (iii) a procedure for intelligent access network selection, and (iv) comprehensive inter-network handover mechanisms

A review of diaphragmless shock tubes for interdisciplinary applications

Shock tubes have emerged as an effective tool for applications in various fields of research and technology. The conventional mode of shock tube operation employs a frangible diaphragm to generate shockwaves. The last half-century has witnessed significant efforts to replace this diaphragm-bursting method with fast-acting valves. These diaphragmless methods have good repeatability, quick turnaround time between experiments, and produce a clean flow, free of diaphragm fragments in contrast to the conventional diaphragm-type operation. The constantly evolving valve designs are targeting shorter opening times for improved performance and efficiency. The present review is a compilation of the different diaphragmless shock tubes that have been conceptualized, developed, and implemented for various research endeavors. The discussions focus on essential factors, including the type of actuation mechanism, driver-driven configurations, valve opening time, shock formation distance, and operating pressure range, that ultimately influence the shockwave parameters obtained in the shock tube. A generalized mathematical model to study the behavior of these valves is developed. The advantages, limitations, and challenges in improving the performance of the valves are described. Finally, the present-day applications of diaphragmless shock tubes have been discussed, and their potential scope in expanding the frontiers of shockwave research and technology are presented.Comment: Review paper, 31 pages, 18 figures, manuscript draf

EBSD mapping of herringbone domain structures in tetragonal piezoelectrics

Herringbone domain structures have been mapped using electron backscatter diffraction (EBSD) in two tetragonal piezoelectrics, lead zirconate titanate, [Pb(Zr,Ti)O<sub>3</sub>] and bismuth ferrite – lead titanate, [(PbTi)<sub>0.5</sub>(BiFe)<sub>0.5</sub>O<sub>3</sub>]. Analysis of the domain misorientations across the band junctions shows that the structures correspond very well to crystallographic models. High resolution mapping with a 20 nm step size allowed the crystal rotation across one of these band junctions in lead zirconate titanate to be studied in detail and allowed an improved estimation of the peak strain at the junction, of 0.56 GPa. The significance of this for crack nucleation and propagation in such materials is discussed