The effect of adjunctive noncontact low frequency ultrasound on deep tissue pressure injury.

The optimal treatment for deep tissue pressure injuries has not been determined. Deep tissue pressure injuries represent a more ominous early stage pressure injury that may evolve into full thickness ulceration despite implementing the standard of care for pressure injury. A longitudinal prospective historical case control study design was used to determine the effectiveness of noncontact low frequency ultrasound plus standard of care (treatment group) in comparison to standard of care (control group) in reducing deep tissue pressure injury severity, total surface area, and final pressure injury stage. The Honaker Suspected Deep Tissue Injury Severity Scale (range 3-18[more severe]) was used to determine deep tissue pressure injury severity at enrollment (Time 1) and discharge (Time 2). A total of 60 subjects (Treatment = 30; Control= 30) were enrolled in the study. In comparison to the control group mean deep tissue pressure injury total surface area change at Time 2 (0.3 cm2 ), the treatment group had a greater decrease (8.8 cm2 ) that was significant (t = 2.41, p = 0.014, r2 = 0.10). In regards to the Honaker Suspected Deep Tissue Injury Severity Scale scores, the treatment group had a significantly lower score (7.6) in comparison to the control group (11.9) at time 2, with a mean difference of 4.6 (t = 6.146, p = 0.0001, r2 = 0.39). When considering the final pressure ulcer stage at Time 2, the control group were mostly composed of unstageable pressure ulcer (57%) and deep tissue pressure injury severity (27%). In contrast, the treatment group final pressure ulcer stages were less severe and were mostly composed of stage 2 pressure injury (50%) and deep tissue pressure injury severity (23%) were the most common at time 2. The results of this study have shown that deep tissue pressure injury severity treated with noncontact low frequency ultrasound within 5 days of onset and in conjunction with standard of care may improve outcomes as compared to standard of care only.

Effects of non contact low-frequency ultrasound on healing of suspected deep tissue injury: a retrospective analysis.

The purpose of this study was to assess the effectiveness of non contact low-frequency ultrasound on the healing of suspected deep tissue injury (SDTI). Participants were adults ranging in age from 28 to 93 years old, with multiple diagnoses including anaemia, diabetes mellitus and hypertension. Data were examined retrospectively on 85 patients (intervention group = 43 and non intervention group = 42) with 127 SDTI (intervention group = 64 and non intervention group = 63). Participants in both groups received standard of care for treating pressure ulcers. A severity score was used to assess SDTI severity before treatment and healing/progression after treatment. This scale measures surface area, wound colour/tissue assessment, and skin integrity with potential scores of 3 to 18 (higher scores indicate greater severity). A significant difference in changes in wound severity was found (t = 5·67, P < 0.000). Difference in mean change scores was 2·52 on the 3-18 severity scale. The decrease in wound severity for the intervention group was 1·45. Severity in the non intervention group increased by 1·06. This exploratory study of the effect of the non contact low-frequency ultrasound provides initial findings that support its use with SDTI.

Development of miotic cross-tolerance between pyridostigmine and sarin vapor.

The organophosphorous nerve agent sarin (GB) and the carbamate pyridostigmine bromide (PB) both inhibit acetylcholinesterase (AChE), leading to overstimulation of muscarinic receptors. Both GB and PB produce miosis through stimulation of ocular muscarinic receptors. This study investigated 2 hypotheses: (1) that the miotic response to PB would decrease following repeated injections; and (2) that repeated administration of PB would result in tolerance to the miotic effect of GB vapor. Rats were injected intramuscularly with saline, 0.04 mg/kg, 0.5 mg/kg, or 1.4 mg/kg of PB twice daily for 8 consecutive days. After day 3, animals injected with 1.4 mg/kg PB developed miotic tolerance. Twenty-four (24) h following the final PB injection, the rats were exposed to GB vapor (4.0 mg/m(3)). A similar magnitude of miosis was observed in all groups after GB exposure. However, the rate of recovery of pupil size in animals pretreated with 0.5 and 1.4 mg/kg PB was significantly increased. Twenty (20) h following exposure to GB vapor, the pupils of animals pretreated with 1.4 mg/kg PB had recovered to 77% +/- 4% of their pre-exposure baseline, whereas the saline-injected controls had recovered to only 52% +/- 2% of their pre-exposure baseline. The increased rate of recovery does not appear to be a result of protection of pupillary muscarinic receptors by the higher doses of PB, as there was no longer PB present in the animal at the time of GB exposure. These results demonstrate the development of tolerance to the miotic effect of PB following repeated exposures, and also suggest that cross-tolerance between PB and GB occurs. However, because the magnitude of the response was not reduced, the PB pretreatment and its associated miotic cross-tolerance does not appear to diminish the effectiveness of miosis as a biomarker of acute exposure to nerve agent vapor.

Toxicity of emerging energetic soil contaminant CL-20 to potworm Enchytraeus crypticus in freshly amended or weathered and aged treatments.

We investigated the toxicity of an emerging polynitramine energetic material hexanitrohexaazaisowurtzitane (CL-20) to the soil invertebrate species Enchytraeus crypticus by adapting then using the Enchytraeid Reproduction Test (ISO/16387:2003). Studies were designed to develop ecotoxicological benchmark values for ecological risk assessment of the potential impacts of accidental release of this compound into the environment. Tests were conducted in Sassafras Sandy Loam soil, which supports relatively high bioavailability of CL-20. Weathering and aging procedures for CL-20 amended into test soil were incorporated into the study design to produce toxicity data that better reflect soil exposure conditions in the field compared with the toxicity in freshly amended soils. Concentration-response relationships for measurement endpoints were determined using nonlinear regressions. Definitive tests showed that toxicities for E. crypticus adult survival and juvenile production were significantly increased in weathered and aged soil treatments compared with toxicity in freshly amended soil, based on 95% confidence intervals. The median effect concentration (EC50) and EC20 values for juvenile production were 0.3 and 0.1 mg kg-1, respectively, for CL-20 freshly amended into soil, and 0.1 and 0.035 mg kg-1, respectively, for weathered and aged CL-20 soil treatments. These findings of increased toxicity to E. crypticus in weathered and aged CL-20 soil treatments compared with exposures in freshly amended soils show that future investigations should include a weathering and aging component to generate toxicity data that provide more complete information on ecotoxicological effects of emerging energetic contaminants in soil.

Tolerance to the miotic effect of sarin vapor in rats after multiple low-level exposures.

Inhibition of acetylcholinesterase (AChE) by the organophosphorous compound sarin (GB) results in the accumulation of acetylcholine and excessive cholinergic stimulation. There are few data in the literature regarding the effects of multiple low-level exposures to GB and other organophosphorous compounds via relevant routes of exposure. Therefore, the present study was undertaken, and is the first, to investigate the effect of low-level repeated whole-body inhalation exposures to GB vapor on pupil size and cholinesterase activity in the eyes and blood. Male Sprague-Dawley rats were exposed to 4.0 mg/m3 of GB vapor for 1 h on each of 3 consecutive days. Pupil size and cholinesterase activities were determined at various points throughout the exposure sequence. The results demonstrate that multiple inhalation exposures to GB vapor produce a decrease in the miotic potency of GB in rats. This tolerance developed at a dose of GB that produced no overt signs of intoxication other than miosis. AChE and butyrylcholinesterase activity did not increase throughout the exposure sequence, suggesting that the tolerance cannot be attributed to a reduced inhibitory effect of GB. A decrease in the amount of GB present in the eye occurred after the third exposure. However, this change is insufficient to explain the tolerance, as there was no corresponding increase in AChE activity. Thus, the mechanism mediating the miotic tolerance observed after multiple inhalation exposures to the nerve agent GB remains uncertain, although several possibilities can be excluded based on the results of the present study.