Low-frequency Ultrasound Device Research Articles

Low-frequency ultrasound for pulmonary hypertension therapy

BackgroundCurrently, there are no reliable clinical tools that allow non-invasive therapeutic support for patients with pulmonary arterial hypertension. This study aims to propose a low-frequency ultrasound device for pulmonary hypertension therapy and to demonstrate its potential.MethodsA novel low-frequency ultrasound transducer has been developed. Due to its structural properties, it is excited by higher vibrational modes, which generate a signal capable of deeply penetrating biological tissues. A methodology for the artificial induction of pulmonary hypertension in sheep and for the assessment of lung physiological parameters such as blood oxygen concentration, pulse rate, and pulmonary blood pressure has been proposed.ResultsThe results showed that exposure of the lungs to low-frequency ultrasound changed physiological parameters such as blood oxygen concentration, pulse rate and blood pressure. These parameters are most closely related to indicators of pulmonary hypertension (PH). The ultrasound exposure increased blood oxygen concentration over a 7-min period, while pulse rate and pulmonary blood pressure decreased over the same period. In anaesthetised sheep exposed to low-frequency ultrasound, a 10% increase in SpO2, a 10% decrease in pulse rate and an approximate 13% decrease in blood pressure were observed within 7 min.ConclusionsThe research findings demonstrate the therapeutic efficiency of low-frequency ultrasound on hypertensive lungs, while also revealing insights into the physiological aspects of gas exchange within the pulmonary system.

The Use of Conventional Lower-Frequency Color Doppler Ultrasound for Flap Planning in the Lower Extremity.

Handheld Doppler is often inaccurate in localization of perforators for pedicled and free flaps. Color Doppler ultrasound (CDU), in contrast, allows more accurate mapping and characterization of perforators to facilitate rapid flap harvest. Forty-seven flaps harvested from the lower extremity were evaluated preoperatively with CDU by a single surgeon with a conventional low-frequency ultrasound device (Philips Sparq, Cambridge, Mass). Flaps evaluated included profunda artery perforator flaps (n = 36), anterolateral thigh flaps (n = 2), pedicled propeller perforator flaps (n = 7), and toe transfers (n = 2). In all cases where a free profunda artery perforator or anterolateral thigh flap was used, the location of the dominant perforator visualized preoperatively correlated exactly with intraoperative findings. In cases where CDU was used preoperatively to locate a large perforator close to a lower extremity defect for reconstruction with a propeller perforator flap, all perforators could be used, and all flaps were successful. Preoperative CDU is particularly useful for flap planning where knowledge of the location of the dominant perforator is critical. This includes planning of thin and superthin free flaps, as well as freestyle perforator flaps. Our clinical experience suggests that this technology should be routinely adopted in certain aspects of reconstructive microsurgery.

Noncontact Phased-Array Ultrasound Facilitates Acute Wound Healing in Mice.

The authors developed a noncontact low-frequency ultrasound device that delivers high-intensity mechanical force based on phased-array technology. It may aid wound healing because it is likely to be associated with lower risks of infection and heat-induced pain compared with conventional ultrasound methods. The authors hypothesized that the microdeformation it induces accelerates wound epithelialization. Its effects on key wound-healing processes (angiogenesis, collagen accumulation, and angiogenesis-related gene transcription) were also examined. Immediately after wounding, bilateral acute wounds in C57BL/6J mice were noncontact low-frequency ultrasound- and sham-stimulated for 1 hour/day for 3 consecutive days (10 Hz/90.6 Pa). Wound closure (epithelialization) was recorded every 2 days as the percentage change in wound area relative to baseline. Wound tissue was procured on days 2, 5, 7, and 14 (five to six per time point) and subjected to histopathology with hematoxylin and eosin and Masson trichrome staining, CD31 immunohistochemistry, and quantitative polymerase-chain reaction analysis. Compared to sham-treated wounds, ultrasound/phased-array-treated wounds exhibited significantly accelerated epithelialization (65 ± 27 percent versus 30 ± 33 percent closure), angiogenesis (4.6 ± 1.7 percent versus 2.2 ± 1.0 percent CD31 area), and collagen deposition (44 ± 14 percent versus 28 ± 13 percent collagen density) on days 5, 2, and 5, respectively (all p < 0.05). The expression of Notch ligand delta-like 1 protein (Dll1) and Notch1, which participate in angiogenesis, was transiently enhanced by treatment on days 2 and 5, respectively. The authors' noncontact low-frequency ultrasound phased-array device improved the wound-healing rate. It was associated with increased early neovascularization that was followed by high levels of collagen-matrix production and epithelialization. The device may expand the mechanotherapeutic proangiogenesis field, thereby helping stimulate a revolution in infected wound care.

Assessment of a low-frequency ultrasound device on prevention of biofilm formation and carbonate deposition in drinking water systems

A device generating low-frequency and low-intensity ultrasound waves was used for mitigating biofilm accumulation and scaling. Two systems were tested: a lab-scale plate heat exchanger operated with continuously recycled water and a continually fed flow-through drinking water pilot used for mimicking water circulation in pipes. Initial deposition of bacterial cells was not prevented by ultrasound wave treatment. However, whatever the tested system, both further calcium carbonate deposition and biofilm growth were markedly inhibited. Biofilms formed in reactors subjected to low-frequency and low-intensity ultrasound waves were weakly attached to the material. Even though the activity of bacteria was affected as shown by their lower cultivability, membrane permeability did not appear compromised. Ultrasound technology sounds very promising in both the mitigation of drinking water biofilm and carbonate accumulation.

Combined industrial olive oil extraction plant using ultrasounds, microwave, and heat exchange: Impact on olive oil quality and yield

In this study, an industrial combined plant (ICP) constructed from a low-frequency ultrasound device, microwave apparatus and heat exchanger is employed to investigate the real possibility of introducing these innovative technologies to the olive oil extraction process and evaluating their influence on olive oil quality and yield. The novelty of this study lies in the simultaneous use of these three technologies to condition the olive paste in a real olive oil extraction plant.Different olive paste treatments were compared in order to define the effects on the olive oil quality and yield.The use of a spiral heat exchanger in addition to the malaxer reduced the malaxation time to 20 min, and with the microwave apparatus it was possible to obtain an entirely continuous process, without interruptions, from the milling phase to the solid-liquid separation phase.The internal spiral aids in moving the paste from the input to output section, resulting in limited operating pressure.Using the ICP device led to an average increase in extractability ranging from 2.30 to 3.85% with respect to the control thesis, for the Arbosana and Arbequina varieties, respectively, but this difference was not statistically significant.Regarding the virgin olive oil (VOO) quality, the use of the ICP did not affect the marketable parameters and total phenol content, while in terms of the process efficiency, the ICP obtained a higher value than the conventional process and improved the extraction yield.

Prospective pilot evaluation of a low frequency ultrasound device for transepidermal delivery of topical actives

Prospective pilot evaluation of a low frequency ultrasound device for transepidermal delivery of topical actives

Reduction of Topical Anesthetic Onset Time Using Ultrasound: A Randomized Controlled Trial Prior to Venipuncture in Young Children

Ultrasound treatment prior to topical anesthetic application has been shown to speed anesthesia onset by enhancing anesthetic penetration into the skin. To evaluate a low-frequency ultrasound device to facilitate absorption of topical anesthetic in young children who require venipuncture. This was a prospective controlled comparison of analgesic effect of a 5-minute application of liposomal lidocaine cream after ultrasound treatment, with a 30-minute application of liposomal lidocaine cream, in children aged 3 to 7 years undergoing venipuncture. Children rated the pain of the venipuncture using the Wong-Baker FACES Pain Rating Scale (FACES) (0 = no pain, 10 = maximal pain), and parents rated their child's pain using a 100-mm (0 = no pain, 100 = maximal pain) visual analogue scale (VAS). Venipuncture skin sites were evaluated for effect immediately posttreatment, and at 24 to 72 hours post phlebotomy. Seventy subjects were enrolled: the first 10 patients comprised a pilot series, receiving the ultrasonic treatment and liposomal lidocaine cream; the next 60 subjects were randomized, including 29 allocated to the ultrasound treatment group, and 31 randomized to the 30-minute control treatment with liposomal lidocaine cream. Demographics were similar between the two groups. Mean child's FACES scale results were similar: Ultrasound group 4.78 (95% CI; 3.06, 6.52), CONTROL group 4.32 (95% CI; 2.82, 5.82) (P = 0.72); and mean parent VAS scores were also the same: Ultrasound: 19.1 (95% CI; 10.3, 27.8), CONTROL: 23.2 (95% CI; 14.7, 31.7) (P = 0.87). Skin effects immediately after ultrasound were limited to minor redness in 9/39 children and significant redness in 2/29 patients. Ultrasound treatment speeds time of onset of liposomal lidocaine cream anesthesia in young children undergoing venipuncture. Side effects were mild in our population.

Low-frequency ultrasound to manage chronic venous leg ulcers.

Chronic leg ulceration costs the NHS around pound 500 million per year (Moffatt and Dorman, 1995) so it is not surprising that the condition attracts attention from manufacturers of medical devices. However, the evidence available for many novel technologies is scant and a systematic approach to product evaluation is essential to avoid the adoption of ineffective and therefore costly measures. A low-frequency ultrasound device was presented in clinic as an aid to stimulate and accelerate healing in otherwise recalcitrant wounds. There followed a systematic evaluation of the product including a literature review of the mode of action, safety and efficacy, followed finally by a product evaluation with case studies used as outcome measures. In this case, the product proved to be a useful tool in the management of chronic wounds, not only for healing but also for pain, pigmentation and odour reduction. The importance of understanding fully a novel technology and how it fits with clinical practice cannot be underestimated.