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PubMed1976

[The radiological appearances of caustic burns in the upper intestinal tract (author's transl)].

Seventy-three caustic burns of the upper gastrointestinal tract were divided into early and late effects; the radiological findings were analysed and, as far as possible, compared with the endoscopic results. The central role of radiology proved to be indisputable, particularly for the demonstration of a perforation, for the control of treatment by drugs or dilatation and before surgery. Endoscopy is of particular value in the diagnosis of caustic burns if the radiological findings are negative, for following treatment and for clarifying atypical late changes in order to exclude malignant degeneration.

Adolescent↗
PubMed1978

Treatment of caustic injuries of the esophagus: a ten year experience.

The methods of managing 32 patients sustaining caustic injuries to the esophagus are assessed. Treatment of these patients must be individualized according to the type of caustic ingested, the degree of burn and other clinical signs. While an aggressive approach is favored for second and third-degree burns in the form of early esophago-gastrectomy with subsequent colon interposition, operation is not necessary. In all patients, particularly those with first-degree burns. The use of antibiotics is recommended as soon as the diagnosis of esophageal injury is established. The efficacy of steroids in preventing stricture formation, especially with third-degree burns, is questioned.

Adult↗
PubMed2006

Caustic activation of rain showers.

We show quantitatively how the collision rate of droplets of visible moisture in turbulent air increases very abruptly as the intensity of the turbulence passes a threshold, due to the formation of fold caustics in their velocity field. The formation of caustics is an activated process, in which a measure of the intensity of the turbulence, termed the Stokes number St, is analogous to temperature in a chemical reaction: the rate of collision contains a factor exp(-C/St). Our results are relevant to the long-standing problem of explaining the rapid onset of rainfall from convecting clouds. Our theory does not involve spatial clustering of particles.

Causality↗
PubMedDate not supplied

Interactive approximate rendering of reflections, refractions, and caustics.

Reflections, refractions, and caustics are very important for rendering global illumination images. Although many methods can be applied to generate these effects, the rendering performance is not satisfactory for interactive applications. In this paper, complex ray-object intersections are simplified so that the intersections can be computed on a GPU, and an iterative computing scheme based on the depth buffers is used for correcting the approximate results caused by the simplification. As a result, reflections and refractions of environment maps and nearby geometry can be rendered on a GPU interactively without preprocessing. We can even achieve interactive recursive reflections and refractions by using an object-impostor technique. Moreover, caustic effects caused by reflections and refractions can be rendered by placing the eye at the light. Rendered results prove that our method is sufficiently efficient to render plausible images interactively for many interactive applications.

Algorithms↗
PubMed2000

Backscattering enhancements for tilted solid plastic cylinders in water due to the caustic merging transition: observations and theory

Bulk shear and longitudinal waves give rise to important contributions to the scattering of ultrasound by tilted finite plastic and rubber cylinders in water. This occurs in situations where either the shear or longitudinal speed is less than the speed of sound in the surrounding water. At a certain critical tilt angle, large backscattering enhancements are observed for finite cylinders, where the wave vector can reverse direction upon reflection from the cylinder truncation. The scattering process is analogous to the enhancement produced by the merging of rainbow caustics of primary rainbow rays in the scattering of light by long dielectric cylinders, also known as the caustic merging transition [C. M. Mount, D. B. Thiessen, and P. L. Marston, Appl. Opt. 37, 1534-1539 (1998)]. A ray theory was developed to model the backscattering mechanism at the critical tilt angle. It employs the idea of the Bravais effective refractive index, convenient for constructing ray diagrams for the projections of rays in the base plane of the cylinder. There is general agreement between the theory and the experiment down to relatively low ultrasonic frequencies (ka as small as 10). The enhancement is the most significant backscattering contribution for a wide range of tilt angles.

Journal Article↗
PubMedDate not supplied

Caustic ingestions and foreign body aspirations: an overlooked form of child abuse.

Caustic ingestions and foreign body aspirations are common occurrences in the pediatric population. The high association between caustic ingestions and foreign body aspirations and family stress with social problems may result in significant morbidity and mortality. It is the purpose of this article to increase physician awareness concerning the possibility that these events may be a form of child abuse. It is hoped that by recognizing the risk of child abuse in these cases the physician can make the appropriate referrals in order to avoid serious injury to the child.

Child↗
PubMed2003

Observation of the enhanced backscattering of light by the end of a tilted dielectric cylinder owing to the caustic merging transition.

The scattering of light by obliquely illuminated circular dielectric cylinders was previously demonstrated to be enhanced by a merger of Airy caustics at a critical tilt angle. [Appl. Opt. 37, 1534 (1998)]. A related enhancement is demonstrated here for backward and near-backward scattering for cylinders cut with a flat end perpendicular to the cylinder's axis. It is expected that merged caustics will enhance the backscattering by clouds of randomly oriented circular cylinders that have appropriately flat ends.

Journal Article↗
PubMed2000

Biotreatment of refinery spent-sulfidic caustic using an enrichment culture immobilized in a novel support matrix.

Sodium hydroxide solutions are used in petroleum refining to remove hydrogen sulfide (H2S) and mercaptans from various hydrocarbon streams. The resulting sulfide-laden waste stream is called spent-sulfidic caustic. An aerobic enrichment culture was previously developed using a gas mixture of H2S and methyl-mercaptan (MeSH) as the sole energy source. This culture has now been immobilized in a novel support matrix, DuPont BIO-SEP beads, and is used to bio-treat a refinery spent-sulfidic caustic containing both inorganic sulfide and mercaptans in a continuous flow, fluidized-bed column bioreactor. Complete oxidation of both inorganic and organic sulfur to sulfate was observed with no breakthrough of H2S and < 2 ppmv of MeSH produced in the bioreactor outlet gas. Excessive buildup of sulfate (> 12 g/L) in the bioreactor medium resulted in an upset condition evidenced by excessive MeSH breakthrough. Therefore, bioreactor performance was limited by the steady-state sulfate concentration. Further improvement in volumetric productivity of a bioreactor system based on this enrichment culture will be dependent on maintenance of sulfate concentrations below inhibitory levels.

Biotechnology↗
PubMed2004

A functional study of caustic strictures of the esophagus in children.

The objective of the present study was to assess esophageal motor function in 21 children (7.5 +/- 2.9 years) with caustic strictures. Esophageal manometry was performed using a water-infusion system interfaced with a polygraph and displayed on a computer screen. The data were compared with those obtained from 9 healthy children. Radionuclide transit was determined by studying deglutition of a single bolus of 99mTc pertechnetate in 10 ml of water. Non-peristaltic low-amplitude and long-duration waves were the most common findings detected in patients with strictures longer than 20% of esophageal length (N = 11). Compared with the control group, these patients presented lower mean amplitude and longer mean duration of waves (24.4 +/- 11.2 vs 97.9 +/- 23.7 mmHg, P < 0.05, and 6.7 +/- 2.4 vs 1.6 +/- 0.1 s, P < 0.05, respectively). Six patients presented low-amplitude waves just below the constricted site. Ten children presented delayed esophageal transit. There was an association between dysphagia and abnormalities on manometry (P = 0.02) and between symptoms and scintigraphy data (P = 0.01). Dysphagia in caustic strictures is due to esophageal motility abnormalities, which are closely related to the scarred segment.

Adolescent↗
PubMed2000

An unusual manifestation of severe caustic injury.

Knowledge of the sequelae of caustic ingestion is of relevance to staff of the Emergency Room, Intensive Care Unit, surgical and gastroenterology services. It poses a considerable management problem and may result in life-threatening complications such as visceral perforation. This case report demonstrates an unusual and previously unreported manifestation of caustic injury.

Adult↗
PubMed2001

[Treatment of caustic stenosis of the esophagus with self-expanding devices].

Caustic stenosis is a serious problem in children due to its complicated resolution and implications in important areas like nutrition, as well as the child's tolerance to the measures taken to correct them. After dealing extensively with this problem over the last twenty five years, always from a conservative approach using traditional methods like dilatations, we believe we have found a technique that brings together all the necessary conditions to achieve a favorable and definitive solution. Our ideal goal to achieve a device that provides a well-tolerated permanent esophageal expansion during the scarring process, also permitting normal swallowing, seems to have been reached through the use of the new generation of silicone stents. The authors present their experience in the first seven cases of caustic stenosis treatment through the placement of silicone stents, describing a precise placement technique while establishing a standard protocol for the use of these devices.

Adolescent↗
PubMedDate not supplied

Biochemical indicators of caustic ingestion and/or accompanying esophageal injury in children.

A prospective clinical study was conducted to evaluate whether or not any biochemical predictor of caustic ingestion and complicating esophageal injury exists. Children who were admitted to the hospital within 24 hours following caustic substance ingestion between 1994 and 2000 inclusive were evaluated. The ingested substance and complaints upon admission were noted. Groups were constructed according to the ingested substances such as household bleach (HB) (Group 1), acid (Group 2) or alkali ingestion (Group 3). Full biochemical analyses, chest X-ray and blood gas estimations were obtained and children were evaluated endoscopically. Seventy-eight children were studied. There were 19, 20 and 39 children in Groups 1, 2, and 3, respectively. There were no sex or age differences among groups (p>0.05). Esophagogastric injury was not encountered in Group 1. Second degree injury was present in 12 and 11 children in Group 2 and Group 3, respectively. Blood pH level was decreased in Group 1 (p=0.013), but not different in Groups 2 and 3 (p>0.05). pH did not differ in patients with or without esophageal injury (p>0.05). While serum uric acid values were significantly increased in children with esophageal burn (p=0.001), serum phosphorus and alkaline phosphatase levels were significantly decreased in children with esophageal injury (p=0.01 and p=0.019, respectively). Blood bicarbonate and serum potassium, chloride, urea nitrogen, creatinine, glutamic-oxaloacetic transaminase, glutamic-pyruvic transaminase, lactic dehydrogenase, calcium, glucose, protein, albumin and bilirubin levels did not differ between group (p>0.05), nor between patients with or without complicating esophageal injury (p>0.05). Low serum pH level is an indicator of HB ingestion. Routine endoscopy may not be necessary in children with normal blood pH values after ingestion. Although normal values of pH, uric acid, phosphorus and alkaline phosphatase levels do not rule out ingestion of an acid-or alkali-containing substance other than HB, increase in uric acid and decreases in phosphorus and alkaline phosphatase levels point to the presence of an esophageal injury.

Acids↗
PubMedDate not supplied

The significance of early panendoscopy in caustic ingestion in children.

Fourteen cases of esophageal and gastric burns following the accidental ingestion of a caustic substance are presented. Early fiberoptic endoscopy was necessary, for it made possible a precise assessment of the severity and extent of injury and the application of proper conservative therapy. Signs and symptoms of caustic burns in children are an unreliable guide to injury, therefore, panendoscopy should be performed as soon as possible. A delay in the performance of a fiberoptic examination could result in the perforation of the affected organs.

Burns, Chemical↗
PubMed1989

[Caustic esophageal stenosis in children: report and prevention].

From 1976 to 1988, 22 caustic burns of the esophagus in children were treated by retrograde dilatations (21 cases), by surgical resection and end-to-end anastomosis (2 cases) and by myotomy of the residual stricture after 12 to 18 months retrograde dilatations (4 cases). 3 deaths are recorded which might have been avoided; the treatment was successful in 11 cases and failed in 4 cases which led to the replacement of the esophagus; dilatations are being continued in 4 cases. In view of these results, the choice of the treatment should not be restricted either to conservative treatment continued in spite of poor results or systematic surgical replacement of the esophagus at an early stage. Furthermore, the use of an intraluminal splint has proved efficient in preventing esophageal stricture in 4 cases of caustic burns at stage III.

Burns, Chemical↗
PubMed1989

[Ingestion of caustic substances in childhood].

Patients who ingest caustic substances continue to pose difficult problems in diagnosis and management. Flexible fiberoptic endoscopy and radiological studies have helped to assess the extent of damage caused by corrosives. A number of non surgical techniques are available for therapy, mainly corticosteroids and antibiotics. In a retrospective study from January 1976 till October 1988 we analysed 86 children aged from 1 month to 11 years. The purpose of our analysis was to check the outcome in patients with corrosive burning treated by standardized therapeutic management. Alkaline household substances caused the injury in 75% of our patients. No lesions were found in 19 patients. There were 21 patients with first degree, 28 with second degree ans 18 with third degree lesions. The diagnosis was confirmed by endoscopy within the first 48 hours. Therapeutic management in 2nd and 3rd degree lesions was based on corticosteroids, antibiotics and early bougienage of the oesophagus over an endless thread. Three patients with 2nd degree and all 18 patients with 3rd degree lesions underwent bougienage. Corticosteroids were given for two to four weeks, depending on the severity of the lesion. Our results demonstrate that early diagnosis and therapy can help to reduce stenosis and prolonged illness of these patients. In addition, public health efforts should be made to educate people about the dangers of caustic substances.

Burns, Chemical↗
PubMed1989

Caustic injury of the upper gastrointestinal tract in adults: a clinical and endoscopic study.

During the past 8 1/2 years, we have treated 34 adult patients admitted for ingestion of caustic materials. In 19 patients the injury was accidental, and in 15 patients ingestion was a suicide attempt. Ingested agents included hydrochloric acid in four patients, sulfuric acid in one patient, a strong alkali such as sodium hydroxide or Drano in 15 patients, liquid bleach in eight patients, detergents in four patients, and ammonia in two patients. Each patient underwent early fiberoptic endoscopic evaluation. The extent and severity of the injury varied according to the ingested agent. Seven patients who had second- or third-degree injury had surgery. One patient who ingested sulfuric acid required hemigastrectomy for pyloric stenosis. Two patients with Drano ingestion had necrosis of the stomach and required total gastrectomy. Five patients with strong alkali ingestion had esophageal strictures, and colonic interposition was performed on four of these patients. No patient who had ingested bleach, ammonia, or detergent required surgery. Panendoscopy after caustic ingestion can be performed safely and provides an accurate guide for therapy. The ingestion of strong acid or alkali may produce profound pathologic changes, which may require surgery for perforation or stricture. Bleach, detergent, and ammonia usually cause mild injuries that will respond with medical treatment.

Adult↗
PubMed1987

Early blunt esophagectomy in severe caustic burns of the upper digestive tract. Report of 29 cases.

Caustic ingestion may cause severe necrosis of the upper digestive tract. Of 520 patients admitted in our department for caustic ingestion, 29 (5.5%) underwent emergency esophagogastrectomy because of transmural necrosis. We used a stripping procedure, which was performed through a cervicotomy and a laparotomy. This method allowed 18 patients (62%) to survive. Thus it appears to be a safer technique than open thoracic esophagectomy, which we used in our earlier experience.

Adolescent↗