Carbon Dioxide Absorption During Inhalation Anesthesia: A Modern Practice.

CO2 absorbents were introduced into anesthesia practice in 1924 and are essential when using a circle system to minimize waste by reducing fresh gas flow to allow exhaled anesthetic agents to be rebreathed. For many years, absorbent formulations consisted of calcium hydroxide combined with strong bases like sodium and potassium hydroxide. When Sevoflurane and Desflurane were introduced, the potential for toxicity (compound A and CO, respectively) due to the interaction of these agents with absorbents became apparent. Studies demonstrated that strong bases added to calcium hydroxide were the cause of the toxicity, but that by eliminating potassium hydroxide and reducing the concentration of sodium hydroxide to <2%, compound A and CO production is no longer a concern. As a result, CO2 absorbents have been developed that contain little or no sodium hydroxide. These CO2 absorbent formulations can be used safely to minimize anesthetic waste by reducing fresh gas flow to approach closed-circuit conditions. Although absorbent formulations have been improved, practices persist that result in unnecessary waste of both anesthetic agents and absorbents. While CO2 absorbents may seem like a commodity item, differences in CO2 absorbent formulations can translate into significant performance differences, and the choice of absorbent should not be based on unit price alone. A modern practice of inhalation anesthesia utilizing a circle system to greatest effect requires reducing fresh gas flow to approach closed-circuit conditions, thoughtful selection of CO2 absorbent, and changing absorbents based on inspired CO2.

Acute ulceronecrotic adverse reaction to potassium hydroxide 5% solution in the treatment of molluscum contagiosum.

Molluscum contagiosum is a common childhood condition, and although it is self-limited, treatments are often prescribed. Several medications are available, but there is no consensus regarding the optimal choice in the pediatric population. We report a child who underwent potassium hydroxide 5% treatment resulting in superficial diffuse erosions caused by the inappropriate application. This underlines the importance of parent education before use of this medication with well-known caustic properties.

Efficacy and safety of topical application of 15% and 10% potassium hydroxide for the treatment of Molluscum contagiosum.

BACKGROUND/OBJECTIVES: Molluscum contagiosum is the most common skin infection in children. One topical treatment used for Molluscum contagiosum is potassium hydroxide. The objective of this study was to compare the efficacy of potassium hydroxide topical treatment at different concentrations with that of placebo in terms of complete clearing of Molluscum contagiosum lesions and to assess the safety and tolerance of potassium hydroxide topical treatment. METHODS: This was a double-blind randomized clinical trial of three treatments (potassium hydroxide 10%, potassium hydroxide 15%, placebo) applied once daily up to complete clearing of lesions (maximum duration 60 days) in 53 children aged 2-6 years in primary health care pediatric offices in Catalonia, Spain. RESULTS: In the intention-to-treat analysis, potassium hydroxide 10% (58.8%, P = .03) and potassium hydroxide 15% (64.3%, P = .02) had efficacy superior to that of placebo (18.8%). The number of Molluscum contagiosum lesions was significantly reduced with potassium hydroxide 10% and 15%. The main efficacy outcome was achieved in 58.8% of children in the potassium hydroxide 10% group (P = .03 vs placebo) and in 64.3% of children in the potassium hydroxide 15% group (P = .02 vs placebo). Potassium hydroxide 10% and 15% were not significantly different in efficacy from each other. Potassium hydroxide 10% and placebo were better tolerated than potassium hydroxide 15%. No adverse events were reported during the study period. CONCLUSIONS: Potassium hydroxide 10% and 15% demonstrated high rates of efficacy in clearing Molluscum contagiosum lesions, with potassium hydroxide 10% being better tolerated.

Comparative study of 5% and 2.5% potassium hydroxide solution for molluscum contagiosum in children.

BACKGROUND: Molluscum contagiosum (MC) is a pediatric viral infection that is fairly contagious. Although various treatment methods are available, the presence of facial lesions limits options of therapy. AIM: We aimed to test an alternative treatment consisting of application of two different concentrations of potassium hydroxide (of KOH 5% solution and of KOH 2.5% solution) aqueous solution. METHODS: In this study we evaluated the effectiveness and side-effects of daily applications of potassium hydroxide (KOH) aqueous solution at 2.5% and 5% concentrations, twice daily in 29 children with MC. Out of a total of 29 patients with molluscum contagiosum included in the study, 13 patients in the 2.5% KOH group and 12 patients in the KOH 5% group completed the study. Families were instructed to apply potassium hydroxide twice a day. The assessment of response and side-effects were performed on days 0, 15, 30, 45 and 60 (visits were numbered 1, 2, 3, 4 and 5, respectively) and one month after. RESULTS: We had a total of 11 (44%) patients who completely recovered after the fifth visit. While eight (66.7%) of these 11 patients were in the 5% treatment group, three (23.1%) patients were in the 2.5% treatment group, and there was a statistically meaningful difference (p < 0.047). Patients with fewer lesions remitted better (p < 0.05). When number of lesions were taken into consideration, difference between the two treatment groups appeared after the fourth visit (p < 0.001). There were no statistical differences between the two groups with respect to side-effects (p = 0.682). CONCLUSIONS: Potassium hydroxide solution at a concentration of 5% was more effective than 2.5% in our patients. The treatment was well-tolerated on the face with the advantage of administration of lower concentrations. This study suggests potassium hydroxide may be a more preferable mode of treatment for molluscum contagiosum lesions on the face.

Reduced burning and stinging associated with topical application of lactic acid 10% with strontium versus ammonium lactate 12%.

Burning and/or stinging is one of the most common concerns expressed by patients using topical therapies for treatment of dermatologic disorders. Topical lactic acid preparations often are used to treat dry scaly skin. In this study, we compared the level of burning/stinging reported by participants with application of lactic acid cream 10% containing strontium versus ammonium lactate lotion 12% and cetearyl alcohol lotion. The mean rating of burning/stinging reported for lactic acid cream 10% with strontium and cetearyl alcohol lotion was lower than ammonium lactate lotion 12% (P<.0001). Based on the study results, lactic acid cream 10% with strontium causes less burning/stinging than ammonium lactate lotion 12%.

Comparing efficacy and safety of potassium hydroxide 5% solution with 5-fluorouracil cream in patients with actinic keratoses: a randomized controlled trial.

BACKGROUND: Actinic keratosis (AK) is a pre-cancerous skin lesion, associated with development of squamous cell carcinoma. Current treatment options are limited. OBJECTIVES: To compare the efficacy and safety of topical 5-fluorouracil cream (5-FU) and potassium hydroxide 5% (KOH) in the treatment of AK. METHODS: Eighteen patients with AK applied KOH solution or 5-FU on each side of their scalp/face, randomly. The efficacy and safety of these treatments were compared. RESULTS: Thirteen (118 lesions) and ten (83 lesions) patients were successfully followed for one and three months, respectively. After one month, KOH showed a better clinical response (81% vs. 58%; p-value = 0.007) and dermoscopic response (KOH, 65% vs. 5-FU, 46%; p-value = 0.04); while no differences were noted after three months (clinical response, 83% vs.70%, p-value = 0.1; dermoscopic response, 76% vs. 59%, p-value = 0.1). No significant differences in the recurrence rate of the lesion between the two groups were noted at the end of the third month (p-value = 0.5). Regarding the safety of the treatments, the risk of developing erythema, scaling, sand swelling was higher in 5-FU group (p-value < 0.0001, for all), while more patients in KOH group had erosion and ulcer (p-value < 0.001 for both). KOH was up to 96% less expensive than 5-FU. LIMITATIONS: Low number of patients and short-term follow-up limited the analysis. CONCLUSION: KOH solution offers a faster and less expensive resolution of AK lesions than does 5-FU. CLINICAL TRIAL CODE (IRCT.IR): IRCT20180909040978N1.

Efficacy and tolerance of the topical application of potassium hydroxide (10% and 15%) in the treatment of molluscum contagiosum: randomized clinical trial: research protocol.

BACKGROUND: Molluscum contagiosum is a non-severe pediatric viral infection. Because it is highly contagious and current treatments have negative aesthetic and psychological effects, we want to test an alternative treatment in the primary care setting, consisting of two different concentrations of potassium hydroxide solution. METHODS/DESIGN: The study design is a double-blind, randomized clinical trial, using three types of topical treatment. The treatment consist of daily applications of potassium hydroxide (KOH) in aqueous solution at 10% and 15% concentration, and a placebo administered in the control group. Four follow-up visits (at 15, 30, 45 and 60 days) are planned to evaluate treatment effectiveness and patient tolerance. The main outcome measure of the trial will be the healing rate, defined as lesion disappearance in the affected zones after the topic application of the experimental treatment. Secondary measures will be the principal characteristics and evolution of the affected zone (surface area, number of lesions, size and density of lesions), treatment tolerance (hyperpigmentation, itching, burning, pain), recurrence rate and the natural evolution of lesions in the control group. DISCUSSION: KOH can potentially be an effective and safe treatment for MC in primary care, and can also reduce referrals to dermatologists and hospital pediatric departments. In addition, KOH may be a valid and less expensive alternative to current invasive treatments (surgical excision).

Comparative study of 5 % potassium hydroxide solution versus 0.05% tretinoin cream for Molluscum Contagiosum in children.

BACKGROUND: Molluscum contagiosum is one of the commonest cutaneous viral infections in children. All treatment modalities are associated with substantial pain, tissue destruction, and frequent recurrence. OBJECTIVES: To compare the efficacy and side effects of KOH 5% solution with tretinoin 0.05% cream for the treatment of molluscum contagiosum in children. METHODS: Fifty patients were randomly divided into 2 groups; 25 each for 5% KOH solution and 0.05% tretinoin cream. The given medication was applied at bed time over molluscum lesions. The assessment of response and side effects were performed weekly for 4 weeks. RESULTS: At the end of 4 weeks, the mean lesion count decreased from 9.48 +/- 3.00 SD to 1.67 +/- 0.58 SD and from 8.35 +/- 2.82 SD to 2.00 +/- 1.00 SD in patients treated with 5% KOH solution and 0.05% tretinoin cream respectively. CONCLUSION: The result of both KOH and tretinoin showed good response, well tolerated by children but between the two, KOH showed fast recovery and most lesions were resolved before 4 week. The side effects could be minimized if applied as stated above. On the other hand, tretinoin showed delayed response and even some of lesion extended beyond 4 week but the side effect were less, and hence can be used in recurrent cases.

[Improvement of local lymph node assay for cosmetics safety evaluation].

OBJECTIVE: To improve the local lymph node assay (LLNA) as an alternative method to detect chemicals for both sensitization and irritation. METHODS: The following chemicals: one negative control: 4-Aminobenzoic Acid, three sensitizers: 2,4-dinitrochlorobenzene (DNCB), Hexyl cinnamic aldehyde (HCA), 2-Aminophenol (2-APC) and two irritations: potassium hydroxide (KOH), sodium lauryl sulphate (SLS) were selected. According to the normal LLNA, groups of female Balb/c mice were treated with test solutions. The thickness of each ear was measured and each auricle was weighed. On the sixth day, the bilateral draining auricular lymph nodes were excised and weighed. The single cell suspensions were prepared, the lymphocyte were counted and the proliferations of lymph cells were detected by cell counting kit-8 (CCK-8). RESULTS: Significant increase in ear thickness and weight were found in groups of KOH, SLS and DNCB (above 0.5%) (P < 0.05), which could be considered as irritants, whereas irritation were not found in 2-APC and HCA. In the allergic test, three sensitizers showed positive, but different sensitivity were found among each index. HCA, DNCB and 2-APC could all obviously augment the weight of lymph node and the lymphocyte count in different groups (P < 0.05). Conspicuous proliferation of lymphocyte were found in DNCB (all group), HCA (above the middle dose) and 2-APC (high dose) by CCK-8. CONCLUSION: The reformed LLNA using auricle thickness and weighing as observed markers for irritation, and using lymph nodes weighing and proliferation of lymphocyte as observed markers for sensitization, could evaluate both sensitization and irritation at the same time.

Randomized placebo-controlled clinical trial on efficacy and safety of topical 10% Potassium hydroxide for molluscum contagiosum treatment in children.

Introduction: Our objective was to assess efficacy, safety and tolerance of topical potassium hydroxide (KOH) 10% for treating Molluscum contagiosum (MC) in children. Material and methods: Randomized, double-blind, placebo-controlled clinical trial including all children 2-16 years with MC infection attending pediatrician primary healthcare visits. The treatment was KOH 10% gel applied once daily up to clearing (maximum 30 days). Results: KOH 10% showed superior efficacy to placebo (55.3% vs 16.3%, p < .001). Time until clearing was inferior with KOH 10% (p = .001). MC lesions were reduced with KOH 10%, which also showed higher efficacy when the instructions of use of the device were modified. KOH 10% patients presented more adverse events (AE) than placebo patients (72.3% vs 31.8%, p < .001). Most patients (91.5%) completely recovered. There were no differences in frequency of AE before and after the change of instructions, intolerance was more frequently reported by parents with new instructions. Conclusions: KOH 10% was superior to placebo in the main efficacy outcome and most secondary efficacy outcomes. KOH 10% patients had more AE and intolerance symptoms than placebo, although there were no severe AE and most patients recovered. KOH 10% is an effective and safe topical treatment for MC infection in children.

Potential environmental risks of nanopesticides: Application of Cu(OH)2 nanopesticides to soil mitigates the degradation of neonicotinoid thiacloprid.

Cu(OH)2 nanopesticides and organic insecticides are continuously applied to soil at a temporal interval, while knowledge about the impact of Cu(OH)2 nanopesticides on organic insecticides degradation is currently scarce, resulting in poorly comprehensive evaluation of the potential environmental risks of Cu(OH)2 nanopesticides. Herein, a commercial Cu(OH)2 nanopesticide formulation (NPF), the active ingredient of NPF (AI-NPF), the prepared Cu(OH)2 nanotubes (NT) with comparable morphology and size to AI-NPF, and CuSO4 were respectively applied to soil at normal doses (0.5, 5 and 50 mg/kg), followed by an application of neonicotinoid thiacloprid after an interval of 21 d, showing that NPF at doses of 5 and 50 mg/kg significantly (p < 0.05) mitigated thiacloprid degradation compared to control and CuSO4. Furthermore, AI-NPF was the primary component that contributed to the mitigation effect of NPF, which was also validated by the NT. Large differences in the degradation efficiency of thiacloprid in sterilized and unsterilized soils with Cu(OH)2 nanopesticides suggested that biodegradation was the primary process responsible for thiacloprid degradation, especially as chemical degradation was negligible. Besides a decrease of thiacloprid bioavailability due to adsorption by Cu(OH)2 nanopesticides, we demonstrated that Cu(OH)2 nanopesticides changed soil microbial communities, reduced nitrile hydratase activity and down-regulated thiacloprid-degradative nth gene abundance, which thus mitigated thiacloprid biodegradation. Clearly, this study shed light on the potential environmental risks of Cu(OH)2 nanopesticide.

The evaluation of three treatments for plantar callus: a three-armed randomised, comparative trial using biophysical outcome measures.

BACKGROUND: Callus is one of the most common foot skin complaints experienced by people of all ages. These painful and unsightly lesions often result in disability. The 'gold standard' of treatment is scalpel debridement by a trained specialist; however, people also seek over-the-counter remedies. There is a lack of clinical evidence for the efficacy of such products, which makes selection by patients and practitioners difficult. METHODS: This randomised, three-armed, parallel, comparative trial aimed to test the efficacy of two home treatments for plantar callus using novel, objective outcome measures (skin hydration using the capacitance method; elasticity using negative pressure application; and surface texture using imaging). Additional outcome measures were: size of callus, quality of life (Foot Health Status Questionnaire) and self-reported participant satisfaction and compliance. The results were compared to a podiatry treatment. Participants were randomly allocated to one of three groups: potassium hydroxide (KOH, 40 %); trichloroacetic acid (TCA); and podiatry treatment. Participants were followed for 3 weeks after their initial intervention appointment (days 7, 14 and 21). The primary outcomes were the change from baseline in callus hydration, elasticity, texture, and size at each of the three time points. The secondary outcomes where: change in quality of life 21 days after treatment; resolution of calluses via visual inspection; and participant compliance and perception. RESULTS: Forty-six participants (61 ft) with plantar calluses were recruited. The podiatry treatment showed immediate and significant changes in all objective outcomes, associated foot pain and function (p <0.01). Lesser changes in skin quality and perceived pain and functional benefits occurred with TCA and KOH over 21 days. CONCLUSIONS: This is the first study where objective outcome measures have been used to measure changes in the nature of skin in response to callus treatments. We found significant differences in plantar callus in response to podiatry and two home treatments. The podiatry treatment showed immediate and significant changes in skin and associated foot pain and function. Lesser, but sometimes comparable, changes in skin and perceived pain and functional benefits occurred with TCA and KOH over 21 days. TRIAL REGISTRATION: ISRCTN14751843 : date of registration: 30 April 2015.

Role of free radicals in uveitis.

In acute inflammation, the tissue damage is generally mediated through polymorphonuclear leukocytes and macrophages. Recent studies on the mechanism of this leukocyte-mediated cytolysis have demonstrated that these cells, on stimulation, release a variety of reactive products. These metabolic products consist of superoxide and hydrogen peroxide, which in turn can form highly reactive species such as hydroxyl radicals. It is believed that these oxygen products play an important role in the tissue damage that occurs in inflammations such as uveitis. The ocular structures contain various antioxidant enzymes that normally protect against free radical mediated injury. In experimental animal models of uveitis, it has been shown that antioxidants and free radical scavengers can function as antiinflammatory agents and can protect the eye from inflammation-mediated tissue damage.

Dimethylthiourea attenuates endotoxin-induced acute respiratory failure in pigs.

We hypothesized that toxic O2 radicals might be important mediators of endotoxin-induced acute respiratory failure in pigs. As a relatively specific scavenger of .OH, we infused dimethylthiourea (DMTU, 1 g/kg) before endotoxemia. Escherichia coli endotoxin (055-B5) was infused intravenously into anesthetized 10- to 14-wk-old pigs at 5 micrograms/kg the 1st h, followed by 2 micrograms.kg-1.h-1 for 3.5 h. During phase 1 (i.e., 0-2 h) and phase 2 (i.e., 2-4.5 h), endotoxin decreased cardiac index (CI) and increased mean pulmonary arterial pressure (Ppa), pulmonary vascular resistance (PVR), alveolar-arterial O2 gradient (AaDo2), and hematocrit (Hct). Endotoxemia also caused leukopenia and increased the postmortem bronchoalveolar lavage fluid (BALF) albumin concentration and wet weight-to-dry weight ratio of bloodless lung. Dimethylthiourea did not significantly modify the phase 1 response. However, during phase 2, DMTU attenuated the endotoxin-induced decrease in CI and increases in Ppa, PVR, Hct, AaDo2, lung water, and BALF albumin concentration. In separate groups of endotoxin- and DMTU + endotoxin-treated pigs, lung microvascular hydrostatic pressure was increased to approximately 16 Torr (by fluid overload) to assess alveolar-capillary membrane permeability. Under these conditions, DMTU markedly attenuated the endotoxin-induced increase in alveolar-capillary membrane permeability. Under these conditions, DMTU markedly attenuated the endotoxin-induced induced increase in alveolar-capillary membrane permeability. We conclude that .OH (and possibly H2O2) significantly contributes to endotoxin-induced lung injury in anesthetized pigs.

Leukocyte-induced tissue injury.

The crucial role of leukocytes in host defense is well known. It is becoming increasingly clear, however, that in addition to their beneficial effects, leukocytes can also cause significant injury to host tissues. In this article, the authors review some of the experimental evidence that supports the role of leukocytes in tissue injury.

Effect of toothbrush variables on wear of dentin produced by four abrasives.

A study was conducted to explore the effect of brush brand, brush hardness, and the concentration of abrasive on the wear of human dentin by four dentifrice abrasives. The two hard brushes produced similar and high levels of abrasion, whereas the two medium brushes of the same brands gave dissimilar and lower levels of abrasion. Dilution changed the ranking of two of the four abrasives.

Cutaneous sensitivity to ultraviolet light and chemical irritants.

This investigation examines the relationship between the sun sensitivity of human skin and its response to chemical irritants. Forty-four Caucasoid subjects with normal back skin were studied. The minimal erythema dose (MED) was determined with the sunburning spectrum of a high-pressure mercury lamp. Cutaneous irritability was quantified using a series of seven irritants of different chemical structure, solubility, and concentrations. The response was either expressed as a threshold value of exposure time (ammonium hydroxide, sodium hydroxide) or was graded after a standard exposure in intensity of whealing (dimethyl sulphoxide) or erythema (sodium lauryl sulphate, quaternium 1, croton oil, kerosene). A significant correlation between the MED and the response to all seven primary irritants was found. The relationship was better for water-soluble irritants than for lipid-soluble ones. Despite marked individual variations the determination of the MED is suggested as a valuable tool in identifying hyperirritable skin. Skin typing based on complexion and sunburn history proved to be less reliable.