Death from caustic ingestion:A case report

Rationale:Acute caustic ingestion from suicidal intent is not usual in emergency departments in developed countries.One of the substances commonly ingested by suicidal patients,phosphoric acid,tends to cause multi-system derangements.Patient’s Concern:A 41-year-old male patient presented with complaints of throat discomfort,severe generalized abdominal pain,and multiple episodes of hematemesis after ingesting a restroom cleaning solution.Diagnosis:Poisoning by acute caustic ingestion(containing<30%phosphoric acid and<4%ethylene glycol).Interventions:The patient was administered 50 mL of 8.4%sodium bicarbonate solution followed by an isotonic sodium bicarbonate solution running at 500 mL/h,a hyperkalemia kit,ceftriaxone,metronidazole,omeprazole,and atropine.The patient then underwent urgent hemodialysis.Outcomes:The patient suffered gastrointestinal bleeding as a result of local caustic injury.In addition,his course of illness was complicated by severe acidemia from high anion gap metabolic acidosis and deranged electrolytes(hyperphosphatemia,hyperkalemia,and hypocalcemia).He developed multi-organ failure and eventually demised.Lessons:The clinician needs to be mindful of the multi-system complications arising from such a caustic ingestion.These patients need to be monitored closely for deterioration,and have prompt management of the various arising complications,to reduce the high morbidity and mortality associated with this condition.

Endoscopic Aspects of Caustic Injuries of the Upper Gastrointestinal Tract in Parakou, Benin Republic: A Multicenter Study

Objective: Caustic ingestion is a medico-surgical emergency. The objective of this study is to describe endoscopic lesions of the upper gastrointestinal tract secondary to caustic ingestion in Parakou, Benin Republic. Patients and Methods: This was a retrospective and descriptive cross-sectional study. The study was multicenter in the gastrointestinal endoscopy units of the Teaching Hospital Center of Borgou-Alibori and the Military Teaching Hospital of Parakou. It covered the period from July 2015 to October 2021. This included any patient who ingested a caustic substance and performed a gastroscopy in one of the two endoscopy units. The variables studied were: socio-demographic data, the nature of the caustic substance ingested, the time between the caustic ingestion and the performance of gastroscopy and injuries of the upper gastrointestinal tract. Results: Out of the 24 patients included, 19 were men, i.e. a sex ratio of 3.8. Their average age was 25.54 ± 12.04 years with extremes of 6 and 50 years. Five subjects (20.83%) were under the age of 18 and the ingestion was accidental in them. Among the 19 patients aged at least 18 years, caustic ingestion was voluntary in 14 (73.68%). The caustic substance ingested was either a base (sodium hydroxide or caustic soda) or an acid (sulfuric acid) in 14 cases (58.33%) and 10 cases (41.67%), respectively. The time between the caustic ingestion and the performance of gastroscopy varied from 1 to 1095 days. The endoscopic lesions objectified were: stenosis (37.5%), ulcerations (29.17%), necrosis (20.83%), or erythema (12.25%). Conclusion: In Parakou, caustic ingestion, usually bases, is often voluntary in adult men. Endoscopic lesions were often ulcerative but sometimes necrotic.

Management of esophageal caustic injury

Ingestion of caustic substances and its long-term effect on the gastrointestinal system maintain its place as an important public health issue in spite of the multiple efforts to educate the public and contain its growing number. This is due to the ready availability of caustic agents and the loose regulatory control on its production. Substances with extremes of pH are very corrosive and can create severe injury in the upper gastrointestinal tract. The severity of injury depends on several aspects: Concentration of the substance, amount ingested, length of time of tissue contact, and p H of the agent. Solid materials easily adhere to the mouth and pharynx, causing greatest damage to these regions while liquids pass through the mouth and pharynx more quickly consequently producing its maximum damage in the esophagus and stomach. Esophagogastroduodenoscopy is therefore a highly recommended diagnostic tool in the evaluation of caustic injury. It is considered the cornerstone not only in the diagnosis but also in the prognostication and guide to management of caustic ingestions. The degree of esophageal injury at endoscopy is a predictor of systemic complication and death with a 9-fold increase in morbidity and mortality for every increased injury grade. Because of this high rate of complication, prompt evaluation cannot be overemphasized in order to halt development and prevent progression of complications.

Caustic injury of the upper gastrointestinal tract: A comprehensive review

Prevention has a paramount role in reducing the incidence of corrosive ingestion especially in children, yet this goal is far from being reached in developing countries, where such injuries are largely unreported and their true prevalence simply cannot be extrapolated from random articles or personal experience. The specific pathophysiologic mechanisms are becoming better understood and may have a role in the future management and prevention of long-term consequences, such as esophageal strictures. Whereas the mainstay of diagnosis is considered upper gastrointestinal endoscopy, computed tomography and ultrasound are gaining a more significant role, especially in addressing the need for emergency surgery, whose morbidity and mortality remains high even in the best hands. The need to perform emergency surgery has a persistent long-term negative impact both on survival and functional outcome. Medical or endoscopic prevention of stricture is debatable, yet esophageal stents, absorbable or not, show promising data. Dilatation is the first therapeutic option for strictures and bougies should be considered especially for long, multiple and tortuous narrowing. It is crucial to avoid malnutrition, especially in developingcountries where management strategies are influenced by malnutrition and poor clinical conditions. Late reconstructive surgery, mainly using colon transposition, offers the best results in referral centers, either in children or adults, but such a difficult surgical procedure is often unavailable in developing countries. Possible late development of esophageal cancer, though probably overemphasized, entails careful and long-term endoscopic screening.

CAUSTIC DECOMPOSITION OF SCHEELITE AND SCHEELITE－WOLFRAMITE CONCENTRATES THROUGH MECHANICAL ACTIVATION

Based on physicochemical study of the reaction between scheelite and NaOH, a new decomposition process for scheelite and scheelitewolframite concentrate, i. e., mechenically activating caustic decomposition has been developed, and it has been successfu

Dynamic caustics test of blast load impact on neighboring different cross-section roadways

Using digital laser dynamic caustics experimental system and conducting simulation experiment researched the influence rule of blasting excavation of a new roadway on neighboring existed different cross-section roadways. The experimental results show that the influence of blast load on adjacent roadway has a good relationship with the cross-section of roadway. The expansion distance of precrack existed in circular, arch-wall, rectangular roadway is respectively 1.76, 1.61 and 0 cm under blast load.At the same time, the direct-blast side of rectangular roadway has more obvious damage compared with circular and arch-wall roadway. It explains that plane reflects more stress wave than arc, so that it exerts more tensile failure in the direct-blast side, which leads to less stress wave diffracting to the precrack in the back-blast side. When the precrack extends, higher value dynamic stress intensity factor in circular roadway works longer than that of arch-wall roadway. Indirectly, it explains that plane's weakening function on stress wave is significantly stronger than arc. Stress wave brings about self-evident influence on the upper and bottom endpoints of the rectangular roadway, and it respectively extends 1.03, 2.06 cm along the line link direction of the center of the blasthole and the upper and bottom endpoints on the right wall.

RAMAN SPECTRA OF SODIUM ALUMINATE SOLUTIONS WITH HIGH-CAUSTIC RATIO AND HIGH CONCENTRATION

The constitution of high-caustic ratio and highly concentrated sodium aluminate solutions hasbeen investigated by Raman spectra method.By comparison with the Raman spectra ofcrystalline solids of Ca3[Al（OH）6]2 and Ba2[Al2（OH）10],it can be concluded thatAI（OH）63-ion and perhaps its polymers may be formed in these solutions.

Role of endoscopy in caustic injury of the esophagus

Caustic injury of the esophagus is a problematic condition challenging endoscopists worldwide. Althoughthe caustic agents and motives are different among countries and age groups, endoscopy still plays an invaluable role in diagnosis and treatment. Endoscopy can determine the severity of caustic ingestion which is of great importance in choosing appropriate treatment. However, some aspects of endoscopy in diagnosis of caustic injury remain controversial. Whether or not all patients need endoscopy, when to perform endoscopy and how to assess the severity are just some examples of these controversies. Due to lack of randomized controlled trials, many findings and suggestions are inconclusive. Computerized tomography scan of the chest and abdomen gains popularity in assessing the severity of caustic injury and avoiding unnecessary surgery. If esophageal stricture eventually develops, endoscopic dilatation is a mainstay. Maneuvers such as steroid injection and esophageal stent may be used in a refractory stricture. Nevertheless, some patients have to undergo surgery in spite of vigorous attempts with esophageal dilatation. To date, caustic injury remains a difficult situation. This article reviews all aspects of caustic injury of the esophagus focusing on endoscopic role. Pre-endoscopic management, endoscopy and its technique in acute and late phase of caustic injury including the endoscopic management of refractory stricture, and the treatment outcomes following each endoscopic intervention are thoroughly discussed. Finally, the role of endoscopy in the long term follow-up of patients with esophageal caustic injury is addressed.

A STUDY OF DYNAMIC CAUSTICS AROUND RUNNING INTERFACE CRACK TIP

Based on the first invariant of stress singular field in the vicinityof running tip of an interface crack, mapping equations of the caustic curve on thereference plane and the initial curve on the specimen plane are developed. The dy-namic caustics are analyzed for the crack propagating along the interface betweentwo bonded dissimilar materials. The variation of the caustic configurations is shownwith the velocity change of the running crack and the ratio change of the stress inten-sity factors. Two characteristic dimensions are proposed that are not only practicallymeasurable from optical caustic contours but also suitable to represent the behaviorof transient caustics.

Upgrading Paper-grade Softwood Kraft Pulp to Dissolving Pulp by Cold Caustic Extraction

Cold caustic extraction has potential applications in the production of dissolving-grade pulps due to its ability to selectively remove hemicellulose from lignocellulosic materials. In this study,we demonstrate the conversion of paper-grade kraft pulp into dissolving pulp by a single-stage cold caustic extraction. Under the extraction conditions of 12 wt% NaOH lye,11% pulp consistency,a temperature of 35℃,and 2 h,a paper-grade softwood kraft pulp was purified to high-grade dissolving pulp with 97. 1% α-cellulose content,1. 2% pentosane content,and narrowed molecular weight distribution. The resulting extraction filtrate was concentrated by nano-filtration to obtain the hemicellulose content of 59. 0 g / L,while the permeate was a clear Na OH solution with 10. 9 wt% concentration. A process configuration was also proposed,integrating this cold caustic extraction process with existing pulp and paper production and multi-purpose utilization of the extraction filtrate.

Esophageal Replacements for Caustic Esophageal Stenosis in Adults about 9 Cases in Ouagadougou

Objective: To report our experience of the esophageal plasty for caustic stenosis of the esophagus. Methods: Retrospective study of caustic stenosis of the esophagus in patients aged over 15 years, operated in Ouagadougou from 2008 to 2016. Nine patients were operated. Patients ranged in age from 25 to 53 years. Caustic ingestion was voluntary in 6 cases. Psychiatric disorders were confirmed in one case. The type of surgery and the postoperative evolution were analyzed. Results: In 6 patients the plasty was preceded by a gastrostomy or a feeding jejunostomy. The transplant, always placed in retro sternal position, was colic in 8 cases and gastric in one case. The evolution was marked by the occurrence of a cervical fistula in 5 cases, postoperative peritonitis in 2 cases, parietal suppuration in 2 cases and pneumothorax in 3 cases. One case of death was noted. After a follow-up of 6 months to 9 years, we noted a case of dysphagia. Conclusion: Esophageal plasty is a saving gesture that restores normal nutrition to the patient. It deserves to be promoted.

EXPERIMENTAL RESEARCH ON STRESS INTENSITY FACTOR K_Ⅲ FOR 3-D CRACK BY CAUSTICS

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An experimental study of the dynamic features of shadow areas of caustics in response to loading/unloading fracture

Using a plexiglass sample and by means of real-time holographic interferometry and shadow optical method of caustics, the different features of dynamic variation in stress (strain) field, plastic area and nucleation zone (shadow area) when the sample fractures during loading (loading-fracture) and unloading (unloading-fracture) are studied visually. The results show that the strain nuclei (zones with dense fringes) appear first at the tips of prefabricated cracks at low stress, and then the shadow areas of caustics form with the increase of load. These nuclei and shadow areas can become larger, or smaller, when the process of loading, or unloading, goes on. When the stress is kept within a certain range, the shadow areas of caustics can become larger and smaller alternatively with repeated loading and unloading (cyclic loading). However, when loading and unloading at high stress, in particular when the macrofracture is about to appear, the variations of the shadow areas of caustics are irreversible and quite different. The shadow areas of caustics expand rapidly at an increasing speed when loading-fracture appears. In contrast, the shadow areas of caustics expand at a lower speed when unloading-fracture appears; besides, there is a circular shadow in front of the sharp-angle shaped area.

Application of caustic method to determining stress intensity factor of compressive shear crack

The caustic method is applied to compressive shear experiment and used to detect the stress intensity factors of cracks prefabricated on plexiglass sample. Loading, friction of crack planes and influence among cracks are not needed to know as they are combined and transformed into the caustic shadow used in detecting the stress intensity factor. Even boundary condition is not necessary. Therefore it is effective to determine the stress intensity factor of compressive shear crack.

Propagation and Coalescence of Blast-Induced Cracks in PMMA Material Containing an Empty Circular Hole Under Delayed Ignition Blasting Load by Using the Dynamic Caustic Method

In this paper,dynamic caustic method is applied to analyze the blast-induced crack propagation and distribution of the dynamic stress field around an empty circular hole in polymethyl methacrylate(PMMA)material under delayed ignition blasting loads.The following experimental results are obtained.(1)In directional-fracture-controlled blasting,the dynamic stress intensity factors(DSIFs)and the propagation paths of the blast-induced cracks are obviously influenced by the delayed ignition.(2) The circular hole situated between the two boreholes poses a strong guiding effect on the coelesence of the cracks,causing them to propagate towards each other when cracks are reaching the circular hole area.(3)Blast-induced cracks are not initiated preferentially because of the superimposed effect from the explosive stress waves on the cracking area.(4) By using the scanning electron microscopy(SEM)method,it is verified that the roughness of crack surfaces changes along the crack propagation paths.

Decomposing scheelite and scheelite-wolframite mixed concentrate by caustic soda digestion

Scheelite and scheelite-wolframite mixed concentrates with different grades were decomposed by caustic soda digestion, and the effects of caustic soda（NaOH） dosage, the ratio of water to ore and the stirring rate on tungsten recovery were studied. The results show that under the conditions that the ratio of water to ore is （0.8,） stirring rate is 500 r·min-1 and the heating time is 2.0 h at （160 ℃,） the recovery of tungsten reaches 98% for scheelite （w（WO3） is （65.04%）） and wolframite containing high proportion of calcium （w（WO3） is 65.58%, w（Ca） is （7.53%）,） when caustic soda dosage is 2.2 and 2.0 times of theoretical value, respectively; the recovery of tungsten can be more than 98%,98% and 96% respectively for low-grade scheelite-wolframite mixed concentrate with （55.78%,） 45.32% and 25.21% WO3, when caustic soda dosage is 2.6,3.2 and 5.5 times of theoretical value, respectively.

Caustic Structure of the Under Water Sound Channel

Using the ray method, an investigation has been carried out on the structure of caustics in the wa- veguide assuming the canonical distribution of the sound velocity with depth. Monochromatic point source of sound was on the axis of the waveguide. There is considered water rays only. It is shown that the spatial part of the phase of a running sound wave does not contain the wave propagation direction and is always a positive quantity. When the trajectories are calculated, it is assumed that inversion of rays occurs at an angle of total internal reflection where the reflection coefficient is equal to unity. This eliminates the horizontal part of the trajectories. At other points, the reflection coefficient is assumed to be zero, and the passing coefficient is equal to unity. With this change in the calculation of ray’s trajectories, the basic structure of the caustics remained the same. It is shown that the boundary line of the caustic is a number of foci in which rays intersect with similar angles out of the source and have neighbour times of propagation. Structure of the sound field along the boundary line of the caustic is periodic. Its period coincides with the wavelength of the field radiated by the source.

Ingestion of Caustics by Children in Brazzaville (CONGO)

Ingestion of caustics by children is serious because of the increase in their frequency and the difficulties due to their management. Objective: To improve the management of caustic lesions in Pediatric Department at the University Hospital of Brazzaville. Patients and Methods: Prospective study was conducted from January 2014 to December 2015 in the Pediatric Departments of the UHB and centers of digestive endoscopy in Brazzaville. All children who ingested a caustic product and hospitalized were included after obtaining parental’s consent. The studied parameters were: Age, sex, nature and quantity of the caustic, the family’s attitude, clinical signs, endoscopic results according to Zagar’s classification, therapeutic modalities and evolution. Results: 8292 children were hospitalized and 68 because of the ingestion of caustic, a frequency of 0.8%. The average age was 23.6 months [2 months - 16 years]. The male sex was predominant (57.4%). Ingestion was accidental in 88.2% and voluntary in 11.8%. Factors favoring ingestion were storage methods (81.5%) and parental’s inattention or negligence (10.8%). Bleach was the most incriminated caustic (54.4%) followed by caustic soda (29.4%). The estimated quantity ingested was assumed to be minimal in 61.7%. Unsuitable acts were practiced by the family before the medical consultation in 66.1%. The dominant symptoms were digestive (47%) and neurological (25%). The average time to perform endoscopy was 48 hours in 88.2%. Endoscopy revealed lesions in 51.7%, the different stages were I (12 cases), II (16 cases) and III (3 cases). The mains factors of gravity were inappropriate gestures (85%) and the non-respect of the fasting (9%). Proton pump inhibitors were used in 50%. The evolution was favorable for in 73.5%. Conclusion: Ingestion of caustics by children is most often accidental favored by the inadequate packaging and storage. Prevention is about educating people in order to reduce their frequency.

Use of conductivity method for online measurement of alkalinity of caustic washing liquid

In this paper,the online measurement of the alkalinity of caustic washing liquid by the conductivity method was discussed,and a working curve of the conductivity vs.alkalinity was established,for which the correlation coefficient is 0.9979(n=7).The influence of the temperature of the caustic washing liquid and the presence of coexisting ions,such as iron and oil,on the accuracy of the conductivity method was discussed.The temperature is compensated for by establishing the correlation between conductivity and temperature.When the iron concentration is≤1000 mg/L,and the oil concentration is≤1000 mg/L,the deviation in the results obtained using the conductivity and titration methods is≤2.5 g/L.The t-test results show that there is no systematic devia-tion between the conductivity and titration methods.The conductivity method has the advantages of a fast response and good real-time performance,which meet the requirements for the online determination of the alkalinity of caustic washing liquid.

The Influence of Heat Treatment on the Caustic Etching Behaviour of the Automotive AA6111 Alloy

The caustic etching behaviour of the automotive AA6111 alloy with different aging conditions that simulate the various levels of heat input within the heat affected zone during the welding heating cycles has been investigated. The alloy dissolution rate was found to substantially increase with the pre-aging temperature, which enhances precipitation of the cathodic Q-phase and results in depletion of the alloy solid solution in magnesium and silicon. On the other hand, enhancing the kinetics of precipitation at high temperatures induces a more uniform distribution the Q-phase precipitates, which minimizes the potential difference between the interiors and boundaries of the adjacent grains. This was observed to reduce the severity of the surface topography developed by subsequent caustic etching surface pre-treatment.