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At least 109 records · Page 6Linked to original sources
PubMed2003

Passive in situ remediation of metal-polluted water with caustic magnesia: evidence from column experiments.

Passive remediation consists of a permeable system that enables the water to pass through while retaining metals by means of biogeochemical reactions. Conventional passive treatments are based on calcite dissolution. This increases the pH to values between 6 and 7, which are insufficiently high to precipitate divalent metals. Alternative treatments are based on sulfate reduction with organic matter in order to precipitate metal sulfides. However, redox reactions are usually too slow to treat large groundwater flows as currently found in gravel aquifers (>50 m/a). Caustic magnesia obtained from calcination of magnesium carbonate was tested as an alternative material to devising passive remediation systems. Caustic magnesia reacts with water to form magnesium hydroxide, which dissolves, increasing the pH to values higher than 8.5. Then zinc and lead are mainly precipitated as hydroxides, copper is precipitated as hydroxysulfate, and manganese(II) is oxidized and precipitated as manganese(III) oxides. Thus, metal concentrations as high as 75 mg/L in the inflowing water are depleted to values below 0.04 mg/L. Magnesia dissolution is sufficiently fast to treat flows as high as 100 m/a. The new precipitates may lead to a permeability drop in the porous treating system. Mixtures of caustic magnesia and an inert material such as silica sand (approximately 50% of each) have been shown to be as reactive as pure magnesia and permeable for a longer time (more than 10 months and 1000 pore vol).

Antacids↗
PubMed2002

Esophageal motility changes in acute and late periods of caustic esophageal burns and their relation to prognosis in children.

BACKGROUND/PURPOSE: Esophageal burns as a result of accidental swallowing of caustic material are seen frequently in children. Severe motor function disorders of the esophagus after caustic burns are already reported covering the late periods. The aim of this study was to detect, follow, and report the clinical results of esophageal motility changes in acute as well as the late periods of caustic esophageal insult and its relation with prognosis in children. METHODS: Esophageal motility was studied in 20 children aged 1.5 to 11 years (mean, 3.8). In the study group, motility of the esophagus was investigated on the fifth day of the burn (after decrease of the edema) and repeated at the end of the third month. To standardize the results, the amplitude and the duration of the pressure waves were recorded at 3 cm above the lower esophageal sphincter (LES), and the velocity in the distal esophagus was calculated. Then the mean values of amplitude, duration, and velocity of 15 swallows were obtained for each patient. RESULTS: At the end of the fifth day, peristaltic response of the esophagus to swallowing was followed in 13 patients. Seven patients were able to swallow water, but no peristaltic response was detected. Therefore, the subjects were divided into 2 groups as motility (+) and motility (-), and each were compared with the control group separately. The amplitude of the pressure wave in the motility (-) group was significantly low when compared with the control group. All the subjects in this group had NaOH burns, and development of severe strictures was detected at the endoscopic examinations after 3 weeks. In motility (+) group, no pathologies were detected except significant decrease in the velocity of the peristaltic wave. Eleven of the subjects in this group had acid burns, and 2 had NaOH burns, and, at the follow-up endoscopic examination after 3 weeks, only one acid burn patient had a slight stricture. Motility measurements conducted at the end of the third month showed that the initial motility (-) group had no changes. No peristaltic response was detected after swallowing, and amplitude of the pressure wave measured at the distal esophagus was significantly lower than the controls. However, in the motility (+) group, decrease in the velocity of the peristaltic wave had disappeared, and there were no differences when compared with the control group. CONCLUSION: It is suggested that the manometric studies of the esophagus give important data about the severity of the initial esophageal injury and have an important role in determining the prognosis.

Burns, Chemical↗
PubMed1996

Motor function of the esophagus after caustic burn.

During the subacute and chronic phases of esophagitis due to ingestion of a caustic substance, the patient commonly displays stricture, esophageal rigidity and dysphagia. We used esophageal manometry, radiology, pH monitoring and 99mTc scintigraphy to investigate esophageal motor function in 25 children (mean age 24 +/- 7 months) with chronic esophagitis after second- and/or third-degree caustic burns. The results were compared with those for a control group of 12 children (mean age 32 +/- 19 months) under surveillance for suspected gastroesophageal reflux (GER) but for whom this pathology was later ruled out. Seventeen (68%) of the lesioned-group children showed esophageal dysfunction as revealed by monitoring of pH over a 24-hour period. Over this period, the mean percentage of time with pH below 4 was 19 +/- 10%, the mean number of reflux episodes was 48 +/- 52, the mean number of reflux episodes lasting longer than 5 min was 10 +/- 5, and the mean duration of the longest reflux episode was 51 +/- 21 min. Manometry indicated that, in the lesioned group, an average of 77 +/- 18% of peristaltic waves were nonpropulsive, while the mean Esophageal Work Index (number of propulsive waves per hour x mean maximum pressure developed during propulsive waves) was 227 +/- 192 units. All of the above means were significantly different (p < 0.01) from the corresponding control-group means. Esophageal strictures were observed in 60% (15) of the children. In 2 cases it was minimal, 2 cases moderate and 11 cases had severe strictures. 99mTc scintigraphy indicated that esophageal transit was slightly delayed in four, moderately delayed in five and severely delayed in 16 of the lesioned-group subjects. There was close correspondence between the results of manometry and scintigraphy as regards severity of esophageal dysfunction. These results indicate that motility disturbances and GER are very frequent sequelae of caustic burns of the esophagus, and should be taken into account when evaluating symptoms and deciding on the therapeutic strategy (including diet) to be followed.

Burns, Chemical↗
PubMed2004

Role of caustics in the formation of networks of amplitude zeros for partially developed speckle fields.

The topology of a partially developed speckle field was studied by use of interference techniques through computer simulation. Amplitude and phase structures in the vicinity of caustics for a coherent radiation field scattered at a surface with large inhomogeneities were investigated. It was confirmed that the caustics are indispensible components of the procedure for the formation of networks of amplitude zeros for a coherent field scattered by a rough surface with large inhomogeneities. It is shown that the formation of interference forklets in the field gives evidence of changes in the field's topology, as these forklets are a diagnostic sign of transition from a caustic to a three-dimensional pattern of a diffraction catastrophe.

Algorithms↗
PubMed2000

Exterior caustics produced in scattering of a diagonally incident plane wave by a circular cylinder: semiclassical scattering theory analysis.

We use the semiclassical limit of electromagnetic wave scattering theory to determine the properties of the exterior caustics of a diagonally incident plane wave scattered by an infinitely long homogeneous dielectric circular cylinder in both the near zone and the far zone. The transmission caustic has an exterior/interior cusp transition as the tilt angle of the incident beam is increased, and each of the rainbow caustics has a farzone rainbow/exterior cusp transition and an exterior/interior cusp transition as the incident beam tilt angle is increased. We experimentally observe and analyze both transitions of the first-order rainbow. We also compare the predictions of the semiclassical approximation with those of ray theory and exact electromagnetic wave scattering theory.

Journal Article↗
PubMed2001

[Severe caustic injuries of the esophagus: when to replace the esophagus].

From June 1985 to May 1998, 20 patients have been treated in our hospital by esophageal dilatations due to serious esophageal caustic stenosis. A retrospective analysis of these 20 patients was performed, evaluating age, sex, causative agent, number and time of dilatations, iatrogenic esophageal perforations, gastroesophageal reflux (GER) and psychological and social consequences. Follow-up has ranged from 1.5 to 14.5 years (mean = 8.07 years). The mean age at the time of accidental swallow was 42.2 months. The causative agent was dishwashing detergent in 11 patients and caustic soda in 9 patients. The mean of dilatations needed was 19.1 and the average duration of dilatations was 24.7 months. Seven patients had esophageal perforation during dilatation and none of them required surgical treatment. All patients had improvement of swallowing and an easier esophageal dilatation afterwards. Oral contrast studies demonstrated distortion of the esophago-gastric junction in the majority of patients. Ten patients were screened for GER with 24-hour esophageal pH monitoring in the first year postburn and it was pathological in 5. Antireflux surgery was carried out in 4 patients with a conspicuous improvement following surgery. Dilatations proved successful in 16 patients in less than two years, and in more than two years in 3 patients. The authors conclude that the majority of children with esophageal caustic stenosis can be managed successfully by esophageal dilatations, even with dilatation periods longer than two years or when an esophageal perforation occur during the procedure. The paramount importance of early diagnosis and treatment of GER is stressed.

Burns, Chemical↗
PubMed1992

[Caustic stenosis of the esophagus in Libreville. Results of the surgical treatment].

41 cases of caustic stenosis of the oesophagus were treated surgically by the thoracic and visceral surgical teams of La Fodation Jeanne Ebori and L'Hopital Pédiatrique d'Owendo in Libreville. The lesions were due to bleach ingestion in 38 cases, caustic soda in 2 cases and sulfuric acid in 1 case. Ingestion was an accident in 29 cases and voluntary in 12. There were 32 men and 9 women. Among them, there were 32 infants and 9 adults. The mean age was 4.5 years for the infants and 25 years for the adults. The surgical procedures were gastrostomy, followed by dilatations of the stenosis in 19 cases, esophagoplasty using the stomach, with pyloroplasty and jejunostomy in 4 cases, and gastrostomy associated with esophagoplasty using the colon in 18 cases. Mortality rate was 2.4%. It was about 1 patient, from general causes. Cervical or thoracic fistulae occurred in 4 patients, all of them successfully treated by medical means, and 3 patients had regressive pulmonary infections. The mean follow-up was 4 years, with good results. The authors suggest a surgical attitude in the management of caustic stenosis, every time the medical management is unsuccessfull.

Adolescent↗
PubMed1990

[Role of endoscopy in caustic gastroesophageal lesions].

From 1984 to 1989 we have examined endoscopically 191 patients who ingested, for different causes, some type of caustic substance. The mean age was 36.8 +/- 21 years. 57% were female and 43% males. The most common substance was lye (52%). The clinical symptoms consisted mainly of epigastric pain and odynophagia. The most prevalent lesion was oesophagitis, of variable degrees (58%). Complications related to the ingestion of the caustic appeared in 20% of the patients; three of them died. The most common sequela was oesophageal stenosis and secondly gastric stenosis. Males ingested acids more frequently than females (P less than 0.001). In 20% of the cases the ingestion of the caustic was for suicide while in children all the cases were accidents.

Accidents↗
PubMed1993

[Caustic burns of the upper gastrointestinal tract. Diagnosis and therapy].

Out of 81 patients with suspected caustic injury 27% showed esophageal lesions. In 5% the lesions were severe and strictures developed and dilatations were necessary. The diagnosis has to be made by endoscopy in each suspected injury to rule it out or to control its steroid therapy. Even without oropharyngeal lesions caustic injury of the esophagus is possible. Endoscopy and dilatation were made under sedation and did not hurt the patients. No complications occurred. Steroids seem to be useful only in severe caustic ingestions.

Adolescent↗
PubMed1998

Esophageal perforations encountered during the dilation of caustic esophageal strictures.

BACKGROUND: The most common cause of esophageal stricture in children is the accidental ingestion of strong alkalies and the life-threatening complication of dilations for treating caustic esophageal strictures is esophageal perforation. METHODS: During a 25-year period between 1971 and 1996, 195 patients with caustic esophageal strictures underwent repeated dilations program and 34 had 36 complicating perforations (17.4%) at the Hacettepe Children's Hospital Department of Pediatric Surgery. A retrospective clinical study was performed to evaluate the risks, results and outcome of esophageal perforations encountered among strictured esophaguses. Thirty-four patients, of whom 19 were male (56%) and 15 female (44%) with 25 (74%) being younger than 5 years of age, were evaluated retrospectively. RESULTS: There was no relation between the type of therapy against stricture formation and perforation of the esophagus. Seventy-five percent of perforations occurred during antegrade dilations with stiff woven dilator and most perforations (69.4%) occurred in the first, second or third dilations. Esophageal perforation was suspected during dilation procedure in 7 perforations while the remaining 29 were diagnosed following a suggestive clinical course. The diagnosis of perforation was confirmed by chest X-ray, esophagography, and esophagoscopy in 30, 5, and 1 perforations respectively. The treatments included antibiotics, digoxin and drainage through gastrostomy among 13 patients, and additionally chest tube drainage among 12 patients, and additionally feeding jejunostomy among 7 patients while three patients underwent only feeding jejunostomy in addition to antibiotics, digoxin and drainage through gastrostomy. Six patients (18%) died, 6 patients (18%) required esophageal replacement for previous cervical esophagostomy or persisting stricture that impairs swallowing. Esophageal strictures in 22 patients (64%) have been treated by dilations. Redilation therapy started within 3 months following perforation and 68% of patients required 2 to 3 years of chronic dilations to be accepted as normal swallowers. CONCLUSIONS: The esophageal perforations encountered during dilating caustic esophageal strictures present a spectrum from a minimal peri-esophageal leakage to massive rupture with pneumothorax causing mediastinal shift and sudden death. The diagnostic and therapeutic approaches should be individualised according to the place of the patient in this spectrum.

Burns, Chemical↗
PubMed1986

Caustic sclerosing cholangitis. A complication of the surgical treatment of hydatid disease of the liver.

In five patients, sclerosing cholangitis developed after the surgical treatment of hydatid cyst of the liver. The cyst communicated with the biliary tree, and a scolicidal solution (2% formaldehyde in two patients and 20% sodium chloride in three) was injected into the cyst. Cholangiography showed strictures affecting the intrahepatic biliary tree in two and both the intrahepatic and extrahepatic biliary tree in three. Sclerosing cholangitis in these patients was likely to result from the caustic effect of the scolicidal solution having diffused from the cyst into the biliary tree. We propose to designate this entity "caustic sclerosing cholangitis". Because of the risk of this complication, and the unproved efficacy of intracystic injection of a scolicidal solution in preventing the dissemination of the parasite, we recommend that this maneuver be abandoned in the surgical treatment of hydatid disease of the liver.

Adult↗
PubMed2003

Arterial blood gas analysis in acute caustic ingestion injuries.

PURPOSE: Quickly differentiating patients who need emergency salvage operation for caustic ingestion injury from those who do not remains difficult. We thus conducted a retrospective study to assess whether arterial blood gas (ABG) analysis is helpful for deciding on the best management plan. METHODS: We divided 129 patients with caustic ingestion injuries into two groups according to treatment. Group 1 consisted of 30 patients who underwent surgery and two who should have. Group 2 consisted of 97 patients treated conservatively. The 30 operated patients in group 1 were further divided into two groups according to whether they survived (group 3) or died (group 4). We analyzed and compared ABG data between groups 1 and 2, and between groups 3 and 4. RESULTS: In groups 1 and 2, the mean pH was 7.22 +/- 0.12 and 7.38 +/- 0.06, respectively, and the mean base excess (BE) was -12.0 +/- 5.2 and -1.8 +/- 3.7, respectively. Both these values were significantly different between groups 1 and 2 (P < 0.001). In groups 3 and 4, the mean pH was 7.27 +/- 0.09 and 7.11 +/- 0.11, respectively, and the mean BE was -10.3 +/- 4.7 and -16.1 +/- 4.6, respectively. Both these values were significantly different between groups 3 and 4 (P < 0.001 and P < 0.005, respectively). CONCLUSIONS. ABG data can help make the right decision about treatment. An arterial pH lower than 7.22 or a BE lower than -12.0 indicates severe injury, and an emergency salvage operation should be seriously considered.

Acute Disease↗
PubMed1976

Pharyngoesophageal caustic stricture. Treatment by pharyngogastrostomy compared to colon interposition combined with free bowel graft.

Four cases of combined hypopharyngeal and cervical esophageal stricture secondary to caustic ingestion are presented. Although gastropharyngostomy has rarely been used for treatment of patients with caustic stricture of the pharynx and cervical esophagus, we believe that it is a useful procedure and has several advantages over use of the colon. We prefer total esophagectomy and posterior mediastinal transposition of the stomach to the neck followed by gastropharyngostomy in those patients who have minimal stomach involvement.

Adolescent↗
PubMed1983

The role of initial cineesophagography in caustic esophageal injury.

The accurate assessment of caustic ingestion requires a vigorous attempt to obtain as much information concerning the type, concentration, and amount of corrosive agent ingested as possible. Although early endoscopy is crucial for assessing the existence of esophageal burns, an accurate prediction of outcome, (for example, stricture) may not be possible from endoscopic study alone. The role of contrast cineesophagography has not been properly emphasized in the surgical literature. Our analysis of the relative accuracy of endoscopy and cineesophagography in esophageal burn evaluation has emphasized that cineesophagography helps in early identification of those patients who will develop strictures. In our experience, cineesophagographically visualized abnormalities, specifically disordered motility, when interpreted within the context of historical facts and physical findings, most accurately prognosticates the outcome of caustic esophageal injuries.

Burns, Chemical↗
PubMed1995

Colon patch esophagoplasty for caustic esophageal stricture.

Severe caustic injury with stricture may require esophageal reconstruction. The available methods of esophageal substitution do not satisfactorily replace the peristaltic and antireflux properties of the native esophagus. The authors report the results of two children treated with colon patch esophagoplasty and preservation of the injured esophagus. Both were 2 years of age when they accidently swallowed lye. Long esophageal strictures developed, which were resistant to repeated dilatation. Eleven and 13 months after the injury, the patients underwent colon patch esophagoplasty. A segment of the left colon was tailored to the length and shape of the opened stricture and was anastomosed side-to-side to the esophagotomy. One child later had a short recurrent stricture and diverticulum, which required revision of the distal end of the anastomosis. Follow-up endoscopic examination has shown healing of the esophagus and resolution of the strictures; both children are eating normally 3 years after surgery, without symptoms of gastroesophageal reflux. Colon patch esophagoplasty is an alternative to esophageal replacement for long caustic esophageal strictures. Its advantage is preservation of the peristaltic and antireflux mechanisms of the conserved esophagus.

Anastomosis, Surgical↗
PubMed1985

The emergency management of caustic ingestions.

Controversial therapeutic issues in patients with caustic ingestions concern the reliability of symptoms and signs in predicting esophageal injury, the appropriate use of endoscopy in evaluating esophageal damage, and the use of steroids in preventing late strictures. The conclusions of this review are: The majority of pediatric caustic ingestions involve a "lick and taste" whereas adolescents and adults often ingest substantial quantities. Oral burns and dysphagia are sensitive predictors of esophageal injury; however, esophageal injury may occur in the absence of the findings. Household bleach and nonphosphate detergents represent a low risk of injury whereas button batteries greater than 20 mm in diameter and Clinitest tablets represent high risk. Endoscopy should be an elective rather than emergency procedure and should be undertaken in all symptomatic patients, and in asymptomatic patients when history indicates substantial ingestion. Steroid therapy should be considered only for patients who have deep or circumferential esophageal burns.

Acids↗
PubMed2004

Caustic burns of rectum and colon in emergencies.

BACKGROUND: Because of their rarity, chemical burns of rectum and colon have been poorly studied. This clinical report studies the epidemiologic, diagnostic, and therapeutic features of rectal and colonic burns after enema with caustics. METHODS: This is a retrospective clinical report of a personal series of 21 patients admitted in our hospital from January 1990 to January 2000 for an acute chemical colitis after enema. RESULTS: Inpatient prevalence: 0.04%. Mean age: 29.7 +/- 12 years (range 17 to 19). Sex ratio: 16 female and 5 male. Circumstances: suicide (n = 14), abortion (n = 3), murder (n = 3), mistake (n = 1). Responsible caustic: sulphuric acid (n = 12), chlorhydric acid (n = 5), potash (n = 2), unknown acid (n = 1), plant decoction (n = 1). Injected quantity: 50 to 250 mL. Ten patients suffered light damage and had an early favorable course under medical treatment, 8 of them had a secondary rectal-sigmoid stenosis. Eleven patients presented with severe necrotic damage, of difficult and often delayed diagnosis based on an enduring symptomatology without clear peritoneal syndrome. Upon surgery, necrotic damage spread on rectum and sigmoid colon (n = 2), up to the transverse colon (n = 4), to the right colonic angle (n = 3), to the right colon (n = 2); once a 10 cm long necrosis of the ileum was associated (n = 1); only 1 patient had a colonic perforation. Performed surgery: 11 resections of necrotic colon and proximal colostomy (Hartman operation). Mortality: 6 patients. Morbidity: 3 of 5 patients. CONCLUSIONS: Chemical burns of rectum and colon produced by strong acid or basic products are necrotizing lesions whose gravity is often hidden by the absence of peritoneal inflammation signs, thus mortality is high. Only early surgery is likely to improve the poor prognosis of severe chemical damage of the rectum and colon.

Abortion, Illegal↗
PubMed1976

Caustic ingestion and subsequent damage to the oropharyngeal and digestive passages.

The characteristics, diagnosis, and management of oropharyngeal and digestive passage lesions due to ingestion of caustic agents are presented. Previous experimental and clinical studies are reviewed with discussion of the peculiar qualities of the newer caustics. Differentiation in treatment of burns caused by solid and liquid agents is stressed.

Animals↗