Emergency treatment of eye burns: which rinsing solution should we choose?

Augenverätzungen

Chemical burns of the ocular surface (CBOS) are emergencies of highest urgency. Therefore, an adequate emergency care is mandatory. Following a precise analysis of the initial damage, a staged therapeutic approach is used to prevent persistent impairment of the ocular surface. In the acute stage, the prevention of complications is targeted (symblepharon, conjunctival scarring, lacrimal stenosis, corneal ulceration, intraocular inflammation, elevated intraocular pressure, etc.). In later stages, if complications have developed, a secondary restoration of the ocular surface is focussed. Sometimes this requires several surgical interventions. Based on a review of international literature, this review highlights the pathophysiology according to different chemical agents, CBOS stages as well as main therapy strategies in early and advanced stages of CBOS. Acute treatment aims to lower inflammation, oxidative stress and tries to promote reepithelialisation. Besides conjunctival scarring, loss of goblet cells and corneal opacification a limbal stem cell insufficiency is the most harming complication. Several new techniques have been developed to recover the ocular surface with a sufficient and clear epithelial layer in order to avoid neovascularization of the cornea. The knowledge concerning the high risk potential for persistent visual impairment in CBOS patients and the ability for appropriate emergency care should be kept in every physician's mind dealing with CBOS.

Ophthalmologic Emergencies: Assessment and Management

There are an estimated 2-3 million emergency department (ED) visits in the United States for eye complaints. Although most patients who present to the ED have nontraumatic eye complaints, many seek treatment for eye trauma, which is a leading cause of unilateral blindness and vison impairment. Given the prevalence of eye-related emergencies, it is imperative that emergency care providers understand how to recognize and treat eye complaints to prevent permanent vision loss and disability. This article covers basic eye anatomy and physiology, discusses a systematic approach to the eye examination, and presents the evidence-based treatment of selected, common nonemergent and emergent eye complaints. For each complaint, essential history questions, examination techniques, differentials, and emergency management have been presented.

Ophthalmic Manifestations of Chlorine Gas Exposure: What Do We Know So Far?

Chlorine gas is a hazardous substance that can cause severe health effects when inhaled or exposed to the skin. It is an odorless, colorless gas in many industrial and manufacturing settings and conflict areas. While exposure to chlorine gas is generally limited to the workplace and public areas, there are instances in which people may be exposed to high levels of chlorine gas for a short period of time due to spills, mishaps on the road or railroads, or other tragedies. In addition to the general health effects of chlorine gas, this essay will focus on the effects of chlorine gas on the eyes. The eyes are particularly sensitive to chlorine gas, and exposure can cause various symptoms, ranging from mild irritation to severe damage. Symptoms of chlorine gas exposure to the eyes include redness, burning, tearing, and blurred vision. In more serious cases, exposure to chlorine gas can cause permanent damage to the eyes, including corneal ulcers, scarring, and blindness. It is important to be aware of the signs and symptoms of chlorine gas exposure and the potential long-term effects to take the necessary steps to protect oneself. In addition to the potential health effects, it is important to understand the properties of chlorine gas. Chlorine gas is heavier than air and tends to settle in low-lying areas. It is highly reactive and can react with other substances to form hazardous compounds. As such, it is important to be aware of the potential for chlorine gas to react with other environmental substances and accumulate in certain areas. Finally, it is important to understand the background of chlorine gas use in various conflict areas. Chlorine gas has been used as a chemical weapon for centuries, and its use in modern warfare has been documented in various conflicts. As such, it is important to be aware of the potential for chlorine gas to be used in war zones and to take the necessary precautions to protect oneself. In conclusion, chlorine gas is a hazardous substance that can cause severe health effects when inhaled or exposed to the skin. The eyes are particularly sensitive to chlorine gas, and exposure can cause various symptoms, ranging from mild irritation to severe damage. It is important to be aware of the signs and symptoms of chlorine gas exposure and the potential long-term effects to take the necessary steps to protect oneself. Additionally, it is important to understand chlorine gas's properties and its background use in various conflict areas.

Noxious effects of riot control agents on the ocular surface: Pathogenic mechanisms and management

Riot Control Agents (RCAs) are chemical compounds used by law enforcement agencies to quell violent demonstrations as an alternative to lethal force and as part of police/military training. They are also known as tear gases because of the hallmark ocular irritation and lacrimation they cause. The most common RCAs include oleoresin capsicum (contained in Mace and pepper spray), chlorobenzylidene malononitrile, dibenzoxazepine, and chloroacetophenone (previously the main content of Mace); some of which have been in use for decades. Their immediate incapacitating effects are mediated through polymodal afferent fibers innervating the corneal surface, inducing the release of peptides that cause neurogenic inflammation. Although previously thought to have only transient effects on exposed patients more severe complications such as corneal stromal opacities, corneal neovascularization, neurotrophic keratopathy, conjunctival necrosis, and pseudopterygium can occur. Concerningly, the lack of research and specific therapies restrict the current management to decontamination and symptom-tailored support. This manuscript will provide an overview of the toxic mechanisms of RCAs, their clinical manifestations, and current therapy after exposure to tear gases.

Clinical outcomes and safety of Diphoterine® irrigation for chemical eye injury: A single-centre experience in the United Kingdom

Purpose:

Diphoterine^® is an amphoteric irrigating solution armed with rapid pH-neutralising action. It serves as an effective first-aid treatment for managing chemical burns, including chemical eye injury (CEI). However, its use is not widely adopted in current clinical practice, primarily attributed to limited clinical evidence. This study aims to highlight the experience in using Diphoterine for managing CEI in a UK tertiary referral centre.

Methods:

This retrospective case series included all patients who presented with CEI and treated with Diphoterine at the James Cook University Hospital, UK, between April 2018 and February 2020.

Results:

Seven patients (10 eyes) were included; the mean age was 28.2 ± 17.0 years (ranged, 3–70 years) and 85.7% were male. All patients presented with an alkaline injury with a mean presenting pH of 8.7 ± 0.7 and a median (±interquartile range [IQR]) corrected-distance visual acuity (CDVA) of 0.10 ± 0.28 logMAR. Based on Roper-Hall classification, 90% and 10% of the eyes were of grade-I and -IV CEI, respectively. All eyes received normal saline/water as the first irrigation fluid and Diphoterine as second irrigation fluid. The mean pH improved slightly after first irrigation (8.4 ± 0.7; p = 0.13) and significantly after second irrigation (7.6 ± 0.4; p = 0.001). The volume of irrigation used was significantly less for Diphoterine (520 ± 193 mL) than for normal saline/water (2700 ± 2451 mL; p = 0.016). At final follow-up (median = 5 days), the median CDVA remained stable at 0.10 ± 0.28 logMAR (p = 0.60). One patient developed near-total limbal stem cell deficiency as a complication of grade-IV injury and was awaiting limbal stem cell transplantation at last follow-up.

Conclusion:

This study represents the first case series in the United Kingdom, reporting the use of Diphoterine in managing CEI. The rapid pH-neutralising action of Diphoterine, with less volume required, makes it an ideal initial treatment for efficiently managing adult and paediatric patients with CEI in clinics.

Corrosive attacks in the UK - Psychosocial perspectives and decontamination strategies

Acid attacks, or vitriolage, are defined as violent assaults involving the deliberate throwing of an acid or similarly corrosive substance with the intention to "maim, disfigure, torture or kill" [1]. The Acid Survivors Trust International suggest a prevalence of 1500 attacks reported worldwide per annum, although this is likely to be an underestimate by 40% [2]. The UK is thought to have one of the highest of rates of recorded corrosive attacks, with an increase from 228 attacks in 2012 to 601 in 2016. Most were reported by the London Metropolitan police force followed by Northumbria, Cambridgeshire, Hertfordshire, Greater Manchester and Humberside [[2]]. The chemical agents involved include acids, alkalis, oxidising and reducing agents, alkylating and chelating agents and solvents. They cause injury by producing a chemical interaction which can lead to extensive tissue destruction and extreme pain. Herein, we present a review on the changing epidemiology of corrosive attacks in the UK and currently employed management strategies.

An update on chemical eye burns

Ocular chemical injuries vary in severity, with the more severe end of the spectrum having profound visual consequences and medicolegal implications. Grading of ocular injuries is critical for determining acute treatment and visual prognosis. Poor immediate management results in more challenging treatment of acute disease. Similarly, poorly controlled acute disease results in more treatment-resistant chronic ocular disease. Despite several decades of research and public health initiatives, simple and effective interventions such as wearing protective eyewear and immediate irrigation of eyes remain as key challenges. Education and prevention are therefore important public health messages. Hurdles in the acute management of disease include poor evidence-base for commonly used treatments (e.g. based on experimental animal studies), reduced treatment adherence rates and high clinic non-attendance rates. The evolution of treatment strategies, particularly limbal stem cell transplantation, has revolutionised the visual and cosmetic outcomes in chronic phases of disease. It is therefore increasingly important to consider tertiary referral for patients with limbal stem cell failure or vision-limiting corneal scarring.

Corneal injury: Clinical and molecular aspects

Currently, over 10 million people worldwide are affected by corneal blindness. Corneal trauma and disease can cause irreversible distortions to the normal structure and physiology of the cornea often leading to corneal transplantation. However, donors are in short supply and risk of rejection is an ever-present concern. Although significant progress has been made in recent years, the wound healing cascade remains complex and not fully understood. Tissue engineering and regenerative medicine are currently at the apex of investigation in the pursuit of novel corneal therapeutics. This review uniquely integrates the clinical and cellular aspects of both corneal trauma and disease and provides a comprehensive view of the most recent findings and potential therapeutics aimed at restoring corneal homeostasis.

First aid therapy for corrosive chemical eye burns: results of a 30-year longitudinal study with two different decontamination concepts

PURPOSE

There is currently uncertainty about the most efficacious decontamination solution for corrosive chemical eye burns. This 30-year longitudinal study evaluated the relative efficacy of two different decontamination methods. Passive decontamination consists of rinsing with tap water, 0.9% normal saline, isotonic buffered phosphate solution, or Ringer's lactate. Active decontamination adds an amphoteric, polyvalent, and chelating component with Previn® (Diphoterine®) solution (Laboratoire Prevor, Valmondois, France).

METHODS

A prospective evaluation of patients treated in two specialized eye clinics for eye burns was begun in 1988. Recorded data included exposure circumstances, type of corrosive, different types of first therapy, and clinical treatment and outcome. Patients were treated from clinic admission and up to 24 h after the corrosive chemical burn with rinsing for 15 min using two different protocols. From 1988 to 2005, sterile 0.9% normal saline or Ringer's lactate was used. Since 2006, sterile, hypertonic, amphoteric Previn® solution was used. Comparative statistical analysis was done with the Fisher contingency tables and Wilcoxon tests.

RESULTS

There were a total of 1495 patients with 2194 chemically burned eyes. In 1988-2005, the annual incidence was 66.1/year; in 2006-2017, it was 65.5/year. Similar incidences were noted when initial rinsing was with tap water or isotonic buffered phosphate solutions. There was a significantly more severe outcome of corrosive chemical eye burns with any first aid rinsing solutions other than Previn® solution or tap water was used (p < 0.001). Previn® solution or tap water rinsing in the pre-hospital setting and secondary rinsing with Previn® solution in the hospital decreased lesion severity in comparison with all other rinsing solutions (p < 0.001).

CONCLUSION

The frequency of corrosive chemical eye burns was comparatively high despite tightening of occupational health and safety regulations over the past 30 years. The severity of corrosive chemical eye burns has been dramatically decreased since the introduction of Previn® solution for initial and secondary rinsing. A new protocol for immediate Previn® solution use by the Cologne Fire Brigade and secondary Previn® solution rinsing in hospital has reduced the frequency of severe corrosive chemical eye burns to less than 60% as compared to the period of 1988-2005 when other rinsing solutions were utilized.

Chemical burns: Diphoterine untangled

OBJECTIVE

Diphoterine is a hypertonic, amphoteric, polyvalent and chelating decontamination solution used in the treatment of cutaneous and ocular chemical burns. Due to infrequent use by emergency physicians along with the small number of available studies, its debate in the literature as to its efficacy and safety remains inconclusive.

METHODS

A structured literature search was performed in MEDLINE, EMBASE BIOLOGICAL ABSTRACTS and TOXNET to June 2016 for original English-language studies reporting on the safety and effectiveness of Diphoterine. Methodological and reporting quality of pre-clinical animal studies was assessed using the Systematic Review Centre for Laboratory Animal Experimentation (SYRCLE) risk of bias tool and Animal Research: Reporting of In Vivo Experiments (ARRIVE) guidelines. Clinical studies were assessed using Chambers' criteria.

RESULTS

13 studies (seven in the pre-clinical, five in the clinical setting and one mixed) met the study inclusion criteria. Pre-clinical studies showed a faster resolution of pH and reduced tissue necrosis with Diphoterine. Clinical studies showed reduced tissue necrosis/severity of symptoms, faster pH resolution and a reduction in pain when using Diphoterine. No adverse events were attributable to Diphoterine. Reporting and methodology of the studies was poor or showed a high risk of bias.

CONCLUSIONS

Diphoterine appears to be safe to use and is probably superior to other rinsing solutions. However, immediate decontamination is imperative and if Diphoterine is not available a different rinsing solution should be used. The methodology of the published literature for Diphoterine is generally poor and future publications should use the frameworks given as templates.

Treatment of acute ocular chemical burns

Ocular chemical burns are an ophthalmic emergency and are responsible for 11.5%-22.1% of ocular injuries. Immediate copious irrigation is universally recommended in acute ocular burns to remove the offending agent and minimize damage. Conventional medical therapy consists of the use of agents that promote epithelialization, minimize inflammation, and prevent cicatricial complications. Biological fluids such as autologous serum, umbilical cord blood serum, platelet-rich plasma, and amniotic membrane suspension are a rich source of growth factors and promote healing when used as adjuncts to conventional therapy. Surgical treatment of acute ocular burns includes the debridement of the necrotic tissue, application of tissue adhesives, tenoplasty, and tectonic keratoplasty. Amniotic membrane transplantation is a novel surgical treatment that is increasingly being used as an adjunct to conventional treatment to promote epithelial healing, minimize pain, and restore visual acuity. Various experimental treatments that aim to promote wound healing and minimize inflammation are being evaluated such as human mesenchymal and adipose stem cells, beta-1,3 glucan, angiotensin-converting enzyme inhibitors, cultivated fibroblasts, zinc desferrioxamine, antifibrinolytic agents, antioxidants, collagen cross-linking, and inhibitors of corneal neovascularization.

Mechanisms of Retinal Damage after Ocular Alkali Burns

Alkali burns to the eye constitute a leading cause of worldwide blindness. In recent case series, corneal transplantation revealed unexpected damage to the retina and optic nerve in chemically burned eyes. We investigated the physical, biochemical, and immunological components of retinal injury after alkali burn and explored a novel neuroprotective regimen suitable for prompt administration in emergency departments. Thus, in vivo pH, oxygen, and oxidation reduction measurements were performed in the anterior and posterior segment of mouse and rabbit eyes using implantable microsensors. Tissue inflammation was assessed by immunohistochemistry and flow cytometry. The experiments confirmed that the retinal damage is not mediated by direct effect of the alkali, which is effectively buffered by the anterior segment. Rather, pH, oxygen, and oxidation reduction changes were restricted to the cornea and the anterior chamber, where they caused profound uveal inflammation and release of proinflammatory cytokines. The latter rapidly diffuse to the posterior segment, triggering retinal damage. Tumor necrosis factor-α was identified as a key proinflammatory mediator of retinal ganglion cell death. Blockade, by either monoclonal antibody or tumor necrosis factor receptor gene knockout, reduced inflammation and retinal ganglion cell loss. Intraocular pressure elevation was not observed in experimental alkali burns. These findings illuminate the mechanism by which alkali burns cause retinal damage and may have importance in designing therapies for retinal protection.

The safety and efficacy of Diphoterine for ocular and cutaneous burns in humans

CONTEXT

Diphoterine, developed by the French company Prevor, is a polyvalent, chelating, amphoteric and slightly hypertonic solution used in the management of chemical cutaneous and ocular burns. While used extensively in Europe and Canada, it is has not been approved by the United States Occupational Safety and Health Administration (OSHA) as an alternative to the water-rinse method due to a lack of evidence of its safety and efficacy on human subjects. An unbiased and extensive systematic review was undertaken in order to better understand Diphoterine's safety and efficaciousness on humans.

OBJECTIVE

Review the safety and efficacy of Diphoterine for treating chemical burns of the skin and eyes in humans.

METHODS

Data sources: Information sources included Pubmed, the National Library of Medicine's Medline Database and the "Publications" sections of the Prevor website. Search terms included Diphoterine, chemical burn, ocular burn and cutaneous burn.

STUDY SELECTION

Any study type published through a peer-reviewed journal up to May 2016 was considered eligible. Published data must have included Diphoterine in the treatment of chemical burns on the skin or eyes as well as meet other specified criteria. Acceptable studies had to use either a quantitative (e.g. number of work days lost) or qualitative (e.g. level of erythema) approach when measuring cutaneous or ocular lesion outcomes.

DATA EXTRACTION

Independent assessment of article inclusion by two authors using predefined criteria.

RESULTS AND CONCLUSION

Diphoterine is safe and highly effective in improving healing time, healing sequelae and pain management of chemical burns on the skin and eyes of humans. Outcomes are significantly improved when compared to water or a physiologic solution equivalent. We recommend that this product be readily available to emergency responders and companies that expose their employees to hazardous chemical substances in order to improve healing sequelae, pain management and lost work days from these types of burns.

Chlorobenzylidene malononitrile tear gas exposure

Objective:

Chlorobenzylidene malononitrile (CS) is the tear gas used by the police. The aim was to evaluate an amphoteric, hypertonic, and chelating rinsing solution in CS exposure.

Methods:

The first (CS) group of six police officers was exposed to CS only. The second (preexposure) group of eight sprayed their faces with an aqueous, hypertonic, amphoteric, and chelating solution before CS exposure. The third (postexposure) group of eight sprayed their faces with an aqueous, hypertonic, amphoteric, and chelating solution after CS exposure. The time between exiting the CS cloud and arriving at the “ready for action” checkpoint was measured. Their facial pain both inside the CS cloud and at the checkpoint was assessed (0–10 points).

Results:

The pain level inside the CS cloud was significantly lower in the preexposed group (5.6 ± 1.1; p = 0.01) than in the CS group (9.7 ± 0.5) and in the postexposure group (9.1 ± 0.4) where it was similar. The time interval between CS exposure and arrival at the checkpoint in the preexposure group (1:26 ± 0:44 min) was significantly shorter than both in the CS group (2:28 ± 0:25 min; p = 0.04) and postexposure group (2:30 ± 0:48 min; p = 0.02) where it was not different. The residual pain at the checkpoint in the preexposure (1.1 ± 0.4) and postexposure (1.4 ± 0.7) groups was similar with a significant lower pain level than in the CS group (2.3 ± 0.5; p = 0.02).

Conclusion:

CS decontamination with an aqueous, hypertonic, amphoteric, and chelating solution reduces facial pain, whereas prevention with it reduces pain and recovery time.

Course and outcome of accidental sodium hydroxide ocular injury

PURPOSE

To evaluate the course and outcome of patients with accidental ocular alkali burns.

DESIGN

Prospective, interventional case series.

METHODS

Study of a cohort of 16 patients (31 eyes) who sustained concomitant accidental sodium hydroxide ocular burns and received appropriate treatment at a tertiary care eye hospital in India. The patients were followed up for 1 year, and parameters including best-corrected visual acuity, epithelial defect area, conjunctival and limbal involvement, and injury-related complications were evaluated.

RESULTS

Severe sodium hydroxide exposure of a mean duration of 12 ± 2.5 minutes and delay in specialist eye care caused moderate to severe injury (grade II, 19% [n = 6]; grade III, 19% [n = 6]; grade IV, 10% [n = 3]; and grade VI, 52% [n = 16]). Median best-corrected visual acuity at presentation was 1.0 logarithm of the minimal angle of resolution (logMAR) units (range, 0.3 to 1.9 logMAR units), and at 1 year, it was 1.0 logMAR units (range, 0 to 1.9 logMAR units; P = .121). The median initial epithelial defect was 100 mm(2) (range, 18 to 121 mm(2)), which healed in all eyes by 3.5 months. Initial median limbal involvement was 12 clock hours (range, 3 to 12 clock hours), resulting in a residual limbal stem cell deficiency of 6 clock hours (range, 0 to 12 clock hours) at 1 year. Most common complications were glaucoma and cataract. Corneal ulcers developed in 2 eyes, and keratolimbal graft was performed in 1 patient. Grade VI injuries had significantly worse outcome than the lower-grade injuries.

CONCLUSIONS

The course and outcome of ocular alkali burns depends on effective first aid (including a thorough eyewash), age, initial grade of injury, response to treatment, prevention of secondary infection, and control of glaucoma. Despite appropriate treatment, these eyes responded poorly and carried a guarded visual prognosis.

[Recommendations for acute treatment for chemical and thermal burns of eyes and lids]

With these recommendations the authors want to improve the acute therapy of eye burns based on the literature and clinical experience. Due to the lack of studies with high evidential value we base these recommendations on the results of experimental work and reports of successfully treated eye burns. A development of this document by systematic research is necessary. Despite the limited knowledge, the collated facts are the current state of the art of treatment according to the knowledge and research of the authors. The most important clinical recommendation is to rinse a chemically or thermally burnt eye as soon and as extensively as possible. Any delay worsens the prognosis. Substances on the market for first aid have different levels of clinical evidence. Thus saline and amphoteric diphoterine have been evaluated in a prospective clinical study showing an advantage for the amphoter. Water, borate buffer, phosphate buffers and derivatives have never been proven to work in clinical applications. Nevertheless, they are recommended. Within experimental work in vitro we could show the value of polyvalent decontamination. Side-effects of phosphate buffers have been demonstrated in retrospective clinical and prospective experimental studies so that even in cases of beneficial effects on pH we cannot recommend these substances which propagate corneal calcification. Special types of burns, such as hydrofluoric acid need special treatment but as clinical studies are lacking only experimental data can offer suitable recommendations.

[Eye irritation and chemical eye burns. Review of experimental and clinical studies]

Chemical burns of the eye are becoming rare due to improvements in occupational protection. Effective decontamination is the foundation for good clinical results of this ophthalmological emergency. The toxicological aspect focuses on classifying the specific toxicity of a chemical substance by evaluating the degree of eye irritation and eye burns. Chemical substances are classified into defined risk levels by specific tests. The traditional ophthalmological approach is based on the clinical presentation of eye burns as a result of contact with a specific toxic substance. In an integral approach it is shown that substance-specific characteristics, such as concentration and specific reactivity as well as individual features, such as mode and duration of exposition have an influence on the clinical appearance of the tissue damage. The decontamination is dependent on the mode of action and the effectiveness of the decontamination solution. Amphoteric substances have the best effectiveness for decontamination of the eye due to their specific characteristics.

A systematic review of methods of eye irrigation for adults and children with ocular chemical burns

AIM

To present the best available research evidence on eye irrigation methods for ocular chemical burns to facilitate better-informed clinical decisions.

METHODS

Randomized, quasi-randomized controlled trials and observational studies comparing the effectiveness of eye irrigation methods among adults or children as an active form of emergency treatment for ocular chemical burns were reviewed. Electronic databases in English and Chinese were searched from inception to June 2010. Two reviewers made independent decisions on whether to include each publication in the review and critically appraised the study quality independently. Given the clinical and methodological diversity among the studies, the review findings are presented in a narrative form.

RESULTS AND DISCUSSION

Four studies involving 302 adults and children were identified. The results of this review indicate that patients who underwent irrigation with tap water immediately following alkali burns at the scene of injury had significantly better clinical and ocular outcomes. The evidence also suggests that in hospital settings, more patients preferred balanced saline solution (BSS) plus than other irrigation fluids. Irrigation with diphoterine was found in one study that resulted in better ocular outcomes following grade 1 and 2 ocular burns. With regard to duration of eye irrigation, patients with ocular chemical burns treated with prolonged irrigation reported shorter duration of treatment at hospital and absence from work. The results should be treated with caution, as there were significant differences between the comparison groups in some studies.

IMPLICATIONS AND CONCLUSIONS

As prompt eye irrigation with tap water immediately after alkali burns had better outcomes, it would be important to commence eye irrigation immediately after burns are sustained. In this review, irrigating fluids including normal saline, lactated Ringer's, normal saline with sodium bicarbonate added, BSS Plus, and diphoterine solutions all yielded positive ocular outcomes suggesting for its use in hospital settings.

Part 2. Comparison of emergency washing solutions in 70% hydrofluoric acid-burned human skin in an established ex vivo explants model

BACKGROUND

Hydrofluoric acid (HF) is a small and partially dissociated acid (pK(a) 3.2), able to deeply penetrate into human skin in addition to the corrosiveness of the hydrogen ion (H(+)) and the toxicity of the fluoride ion (F(-)). However, there has been a lack of experimental studies to objectively characterize the results of human HF skin exposure decontamination.

METHODOLOGY/PRINCIPAL FINDINGS

A previously established experimental method using a human skin explants ex vivo model (Part 1. Experimental 70% hydrofluoric acid (HF) burns: Histological observations in an established human skin explants ex vivo model) described the lesions that appeared following 70% HF penetration. Within 5 min, 70% HF penetrates to the dermis. Using the same experimental conditions, a comparison study of two different washing protocols was performed: water + topical calcium gluconate (CaG) versus Hexafluorine(®). In these conditions, washing for 15 min with running tap water followed by topical CaG ointment only delayed burn onset, while severe tissue damage appeared later. In contrast, after washing with Hexafluorine(®) over 10 min, no histological lesions developed. These results are in accordance with the results of accidental human industrial case reports.

CONCLUSION/SIGNIFICANCE

Amphoteric and hypertonic Hexafluorine(®) can deactivate H(+) and chelate F(-) ions. Based on these results, it should be considered as a promising first-aid decontamination solution to prevent or minimize significant local and systemic consequences of concentrated HF skin exposures.

A 14-year-old girl who regained normal vision after bilateral visual impairment following hot water injury to the eyes

A 14-year-old girl presented with bilateral visual impairment following hot water injury to the eyes. The patient was admitted for a week and managed with guttae tropicamide 0.5% 8 h, diclofenac sodium 0.1% 4 h, and fluoroquinolone 0.3% 6 h and ointment chloramphenicol 8 h. Also, the patient was managed with capsule doxycycline 100 mg 12 h for 10 days, tablet cataflam 50 mg 12 h for 7 days and intramuscular tetanus toxoid 0.5 mg stat and dermacine cream for facial scald. The visual acuities improved from 3/60 (right eye) and 6/24 (left eye) to 6/6 in both eyes. There were resolutions of facial/eye pain, tearing, photophobia, lid edema, blepharospasm, and conjunctival hyperemia. There was complete healing of facial wounds and corneal ulcers. She was discharged from hospital on the 7th day of admission. Prompt presentation, degree of scald sustained, and appropriate medical intervention enhanced visual recovery and wound healing in the patient.

Eye irrigation for patients with ocular chemical burns: a systematic review

AIM

The aim of this systematic review is to present the best available research evidence on eye irrigation methods for ocular chemical burns.

INCLUSION CRITERIA

Randomized, quasi-randomized controlled trials and observational studies comparing the effectiveness of methods of eye irrigation among adults or children as an active form of emergency treatment for ocular chemical burns were considered for review. Studies were eligible for inclusion if methods of eye irrigation were examined within the following comparison categories: time to commence first eye irrigation; types, volumes, durations, flow rates and temperature of eye irrigating fluids; and comfort measures during eye irrigation. The types of outcome measures include immediate ocular outcomes and complications, clinical outcomes, self-reported outcomes, length of hospital stay and working days lost.

SEARCH STRATEGY

Electronic bibliographic databases in English and Chinese were searched from inception to June 2010 and yield 8,999 citations. Other sources were searched by hand to identify studies or additional relevant source materials. The reference lists and bibliographies of all articles retrieved were scrutinized to identify further studies and added a further 22 articles. A forward search on the authors of the studies identified was also performed.

METHODOLOGICAL QUALITY

A study eligibility verification form was developed for the assessment and two reviewers made independent decisions on whether to include each publication in the systematic review. Critical appraisals of study quality were undertaken independently by two reviewers using the Joanna Briggs Institute critical appraisal tools. Any disagreement that arose between the two reviewers was resolved by discussion.

DATA EXTRACTION

Data extraction was performed by one reviewer using a data extraction form developed for the systematic review. Another reviewer checked for accuracy.

DATA SYNTHESIS

Given the clinical and methodological diversity among the studies included in this review, the review findings are presented in a narrative form and no meta-analysis has been performed.

RESULTS AND DISCUSSION

A total of four studies involving 302 adults and children with ocular chemical burns met the inclusion criteria for the systematic review. One study determined the effects of prompt irrigation of the eyes with tap water immediately after alkali burns had been suffered at the scene of injury. The authors report that patients who underwent immediate irrigation had significantly better clinical and ocular outcomes. One study compared four ocular irrigation fluids administered in an emergency department and found more patients preferred a modified saline (balanced saline solution plus) than other type of irrigation fluids. Another study compare the effectiveness of two ocular irrigation fluids in hospital setting reported that for patients with grade 1 and 2 burns, the time elapsed to re-epithelialization was shorter in the group rinsing with diphoterine when compared with the group rinsing with normal saline. The results in another study demonstrated that patients with ocular chemical burns treated with prolonged irrigation reported shorter duration of treatment at the hospital and absence from work. However, the results should be treated with caution, as there were significant differences between the comparison groups in some studies, and incomplete details on methods of random assignment and a small sample size were issues of concern.

CONCLUSIONS

There is insufficient evidence to determine the optimal eye irrigation methods to improve ocular and clinical outcomes. Randomized trials using sample sizes with adequate power are needed to compare the clinical benefits of eye irrigation methods and further trials should take into account the potentially important factors such as the time to commence eye irrigation and cumulative effects of irrigating fluids that might affect the outcomes and adopt strategies to deal with them.

IMPLICATIONS FOR PRACTICE

Currently there is insufficient evidence to inform practice of eye irrigation among adults or children as an active form of emergency treatment for ocular chemical burns. Healthcare professionals need to continuously update themselves about the latest evidence on the optimal methods of eye irrigation in enhancing patient outcomes.

IMPLICATIONS FOR RESEARCH

More well designed randomized and quasi-experimental trials with adequate sample size are needed to further examine the effective methods of eye irrigation for ocular chemical burns. Future studies should provide sufficient information about the demographic and clinical data including the types and severity of ocular injuries, causative chemicals, first-aid management, and time elapsed to eye irrigation. Furthermore, a clear description of the eye irrigation protocol is crucial to facilitate comparisons across studies.

POTENTIAL CONFLICT OF INTERESTS

The authors of this systematic review do not have any type of conflict of interest.

Household chemicals: management of intoxication and antidotes

Exposure to household products is very common, but in industrialized countries severe or fatal poisoning with household products is rare today, due to the legal restriction of sale of hazardous household products. The big challenge for physicians, pharmacologists and toxicologists is to identify the few exceptional life-threatening situations where immediate intervention is needed. Among thousands of innocuous products available for the household only very few are hazardous. Substances found in these products include detergents, corrosives, alcohols, hydrocarbons, and some of the essential oils. The ingestion of batteries and magnets and the exposure to cyanoacrylates (super glue) can cause complications in exceptional situations. Among the most dangerous substances still present in household products are ethylene glycol and methanol. These substances cause major toxicity only through their metabolites. Therefore, initial symptoms may be only mild or absent. Treatment even in asymptomatic patients has to be initiated as early as possible to inhibit production of toxic metabolites. For all substances not only the compound itself but also the route of exposure is relevant for toxicity. Oral ingestion and inhalation generally lead to most pronounced symptoms, while dermal exposure is often limited to mild irritation. However, certain circumstances need special attention. Exposure to hydrofluoric acid may lead to fatal hypocalcemia, depending on the concentration, duration of exposure, and area of the affected skin. Accidents with hydrocarbon pressure injectors and spray guns are very serious events, which may lead to amputation of affected limbs. Button batteries normally pass the gastrointestinal tract without problems even in toddlers; in rare cases, however, they get lodged in the esophagus with the risk of localized tissue damage and esophageal perforation.

Analysis of hydrofluoric acid penetration and decontamination of the eye by means of time-resolved optical coherence tomography

So far the study of chemical burns has lacked techniques to define penetration kinetics and the effects of decontamination within biological structures. In this study, we aim to demonstrate that high-resolution optical coherence tomography (HR-OCT) can close this gap. Rabbit corneas were exposed ex vivo to 2.5% hydrofluoric acid (HF) solution, and microstructural changes were monitored in the time domain by OCT imaging. HF application and penetration resulted in shrinkage of the corneal thickness, interpreted as a result of osmolar changes and of loss of water-binding capacity, and a substantial increase in OCT signal amplitudes. The effectiveness of different rinsing solutions on the chemical burn was also evaluated. With tap water and with 1% calcium gluconate, the deep corneal stroma remained clear until the end of the rinsing period but became opaque afterwards. With Hexafluorine, the cornea remained clear for 60 min after rinsing ceased. We conclude that HR-OCT can assist in the clinical evaluation of an ex vivo eye irritation test, and that decontamination of an HF burn using Hexafluorine is efficient.

Rinsing with isotonic saline solution for eye burns should be avoided

BACKGROUND

Recent approaches to emergency treatment of eye burns have given rise to many questions on the effectiveness of traditional rinsing solutions. This led us to study the use of isotonic saline solution and a recently introduced, highly effective solution, Cederroth Eye Wash, in the initial treatment of eye burns.

METHODS

A central area (Ø 10mm) of the cornea of isolated ex vivo rabbit eyes was burnt for 20s with 25+/-1.4 micro L of 2N NaOH. The anterior chamber pH was measured continuously via microelectrode. The corneas were immediately rinsed for 15 min with flow rates of 50, 100, 200, 300, 400, and 500 mL/min.

RESULTS

After 20 min measurement, no significant differences in intraocular pH were found between unrinsed eyes and eyes rinsed with isotonic saline solution at any flow rate. At all flow rates, Cederroth Eye Wash brought about a significant decrease (p<0.001; Tukey t-test).

CONCLUSIONS

Isotonic saline solution was ineffective in the emergency treatment of severe alkali eye burns in this ex vivo rabbit eye model. Cederroth Eye Wash, even at the lowest flow rate, significantly reduced intracameral pH. Thus a small amount of buffer solution effectively decontaminated the eye, whilst large amounts of saline solution did not.

Chemical, thermal, and biological ocular exposures

Chemical or radiant energy injuries to the eyes are considered ocular burns. The majority of these injuries are occupation-related. Chemical burns are by far more common and represent a true emergency. Thermal and UV injuries are associated with severe pain, but often result in less long-term sequelae than chemical injuries do. The term "biologic exposure" refers to an exposure to human blood or other body fluid. This article describes patterns of these injuries and exposures, with particular emphasis on emergent management and including acute diagnostic and treatment considerations.

Dynamic analysis of chemical eye burns using high-resolution optical coherence tomography

The use of high-resolution optical coherence tomography (OCT) to visualize penetration kinetics during the initial phase of chemical eye burns is evaluated. The changes in scattering properties and thickness of rabbit cornea ex vivo were monitored after topical application of different corrosives by time-resolved OCT imaging. Eye burn causes changes in the corneal microstructure due to chemical interaction or change in the hydration state as a result of osmotic imbalance. These changes compromise the corneal transparency. The associated increase in light scattering within the cornea is observed with high spatial and temporal resolution. Parameters affecting the severity of pathophysiological damage associated with chemical eye burns like diffusion velocity and depth of penetration are obtained. We demonstrate the potential of high-resolution OCT for the visualization and direct noninvasive measurement of specific interaction of chemicals with the eye. This work opens new horizons in clinical evaluation of chemical eye burns, eye irritation testing, and product testing for chemical and pharmacological products.

The consequences of delayed intervention when treating chemical eye burns

BACKGROUND

Immediate rescue intervention for chemical and thermal eye burns can save the victim's sight. We studied the anterior chamber pH changes immediately after ex vivo eye burn to investigate the effects of immediate and delayed intervention.

METHODS

Twenty three enucleated pigs eyes were burnt with 500 microl 2 mol NaOH for 20 s using a cylinder with a diameter of 10 mm. The corneas were rinsed in groups with 1015 ml ordinary tap water at a flow rate of 1.125 ml/s for 15 minutes immediately after burning (n = 6), and after a delay of 20, 40, and 60 s (n = 5, 3 and 4 respectively). One group of eyes was not rinsed (n = 5). The intraocular pH was defined at the start as 'min pH' and the end as 'max pH'(DeltapH = max pH-min pH).

RESULTS

The intraocular pH increased sharply in the untreated eyes from a min pH of 6.76 +/- 0.55 to a max pH of 11.85 +/- 0.24, yielding a DeltapH of 5.08. The difference between the timepoint at which the pH began to increase and the speed of change was significantly different between the unrinsed and rinsed eyes, and there was an inverse correlation between this and the time at which rinsing started (p < 0.001). The best results were achieved in eyes rinsed immediately after burning (p < 0.001). The pH in the eyes not rinsed immediately increased rapidly, and in all groups in which rinsing was delayed the max pH was markedly higher (p = 0.093).

CONCLUSIONS

Immediate emergency rinsing is essential in eye burn victims. Appropriate rinsing solutions and treatment facilities in the form of rinsing stations where chemical burns may occur must be available at the workplace. Tap water is also effective as a rinsing solution.