Oxygenation Status in Chronic Leg Ulcer After Topical Hemoglobin Application May Act as a Surrogate Marker to Find the Best Treatment Strategy and to Avoid Ineffective Conservative Long-term Therapy

Adjunctive topical oxygen therapy in the management of complex diabetes-related wounds: A South African case study series

Diabetic foot ulcers (DFUs) are a prevalent complication of diabetes mellitus and are associated with significant morbidity and mortality. The essential role of oxygen in the treatment of DFUs is documented. Indicated for use on a variety of wound types, topical haemoglobin therapy (Granulox®) is a novel therapeutic technology that binds atmospheric oxygen and improves the availability of oxygen at the wound site. When used as part of the wound management strategy, this therapy helps to reduce inflammation, exudate and slough, and promotes wound healing. In South Africa, health resources, coordinated foot care and podiatry, and data on diabetic foot complications are limited. Twelve patient case studies assessing the impact of adding topical haemoglobin therapy to the management regimes for DFUs and surgical (post-amputation) wounds were undertaken in South Africa. Patients were aged 50-71 years, and all had diabetes mellitus. At baseline, the area of the wounds ranged from 10.2 to 149.6 cm2 with depths ranging from 0.2 to 0.9 cm. Clinical signs of wound infection and high levels of viscous exudate were recorded in all cases. Wound dressings were changed twice weekly and sharp debridement of the wound performed as necessary. The wounds were cleansed and then completely coated with a thin film of Granulox® and dressings applied. Treatment was monitored over periods ranging from 57 to 276 days, during which dressings were changed and Granulox® administered to the wounds, ranging from 16 to 79 times. During the period of evaluation, wound size steadily reduced (by 87.1-100%), the condition of the wound bed tissue and peri-wound skin improved, and clinical signs of wound infection steadily resolved. Wounds significantly improved in two patients, almost healed in six patients, and healed in four patients. All patients reported a reduction in malodour and pain; seven patients were pain-free at the final followup assessment. The overall impression of Granulox® was rated as 'very good' by the clinicians, who considered that Granulox® facilitated an increase in tissue viability, with the promotion of granulation tissue, and stimulated epithelialisation.

Capillary Dynamics Regulate Post-Ischemic Muscle Damage and Regeneration in Experimental Hindlimb Ischemia

This study aimed to show the significance of capillary function in post-ischemic recovery from the perspective of physiological parameters, such as blood flow, hemoglobin oxygenation and tissue regeneration. Muscle-level microvascular alterations of blood flow and hemoglobin oxygenation, and post-ischemic myofiber and capillary responses were analyzed in aged, healthy C57Bl/6J mice (n = 48) and aged, hyperlipidemic LDLR-/-ApoB100/100 mice (n = 69) after the induction of acute hindlimb ischemia using contrast ultrasound, photoacoustic imaging and histological analyses, respectively. The capillary responses that led to successful post-ischemic muscle repair in C57Bl/6J mice included an early capillary dilation phase, preceding the return of arterial driving pressure, followed by an increase in capillary density that further supported satellite cell-induced muscle regeneration. Initial capillary enlargement was absent in the LDLR-/-ApoB100/100 mice with lifelong moderate hypercholesterolemia and led to an inability to recover arterial driving pressure, with a resulting increase in distal necrosis, chronic tissue damage and a delay in the overall recovery after ischemia. To conclude, this manuscript highlights, beyond arterial collateralization, the importance of the proper function of the capillary endothelium in post-ischemic recovery and displays how post-ischemic capillary dynamics associate beyond tissue blood flow to both hemoglobin oxygenation and tissue regeneration.

Venous, Arterial, and Neuropathic Leg Ulcers With Emphasis on the Geriatric Population

Leg ulcers are a common and often serious problem in older adults. Underlying conditions that increase risk include age-related increases in chronic venous insufficiency, peripheral artery disease, connective tissue and autoimmune conditions, reduced mobility, and diabetes mellitus (DM). Geriatric patients have a higher risk of multiple wound-related complications including infection, cellulitis, ischemia, and gangrene, any of which may lead to further complications including amputation. The very presence of these lower extremity ulcers in the elderly negatively impacts their quality of life and ability to function. Understanding and early identification of the underlying conditions and wound features are important for effective ulcer healing and complication mitigation. This targeted review focuses on the three most common types of lower extremity ulcers: venous, arterial, and neuropathic. The goal of this paper is to characterize and discuss the general and specific aspects of these lower extremity ulcers and their relevancy and impact on the geriatric population. The top five main results of this study can be summarized as follows. (1) Venous ulcers, caused by inflammatory processes secondary to venous reflux and hypertension, are the most common chronic leg ulcer in the geriatric population. (2) Arterial-ischemic ulcers are mainly due to lower extremity vascular disease, which itself tends to increase with increasing age setting the stage for an age-related increase in leg ulcers. (3) Persons with DM are at increased risk of developing foot ulcers mainly due to neuropathy and localized ischemia, both of which tend to increase with advancing age. (4) In geriatric patients with leg ulcers, it is important to rule out vasculitis or malignancy as causes. (5) Treatment is best made on a case-by-case basis, considering the patient's underlying condition, comorbidities, overall health status, and life expectancy.

Use of topical haemoglobin spray in hard-to-heal wound management: a systematic review

OBJECTIVE

To synthesise the best available evidence regarding the effectiveness of using topical haemoglobin spray to promote healing in hard-to-heal wounds in adults.

METHOD

The search strategy of this systematic review was designed to retrieve studies published across CINAHL, Medline, Cochrane Central Register of Controlled Trials, Web of Science, Embase, ERIC, Scopus and Mednar, before January 2020, and published in English. All study participants were aged ≥18 years. This review included randomised controlled trials, case-control studies and observational studies. The studies selected for retrieval were assessed by two independent reviewers for methodological validity prior to inclusion using standardised critical appraisal instruments.

RESULTS

The review included 15 studies. Overall effectiveness was demonstrated for wound closure rates, reductions in wound size, severity of wound pain and patient satisfaction with using a topical haemoglobin spray. The meta-analysis revealed a statistically significant effect of a topical haemoglobin spray in reducing the size of venous leg ulcers (VLU, effect size=0.02; 95% confidence interval: 0.00-0.09; p<0.00001) in adult patients. However, evidence of the effectiveness of using a topical haemoglobin spray in different wound types among adult patients was limited and not high-level, which precludes any strong conclusions.

CONCLUSION

The review provides an evidence-based guide to future priorities for clinical practice. In particular, a topical haemoglobin spray was shown to have a positive impact in reducing VLU size and promoting wound healing.

A Pragmatic, Single-Center, Prospective, Randomized Controlled Trial of Adjunct Hemoglobin-Mediated Granulox Topical Oxygen Therapy Twice Weekly for Foot Ulcers

BACKGROUND

Achieving timely healing of foot ulcers can help avoid complications such as infection and amputation; topical oxygen therapy has shown promise in achieving this. We evaluated the clinical effectiveness of Granulox, a hemoglobin spray device designed to deliver oxygen to the surface of wounds, for the healing of foot ulcers.

METHODS

We conducted a single-center, prospective, randomized controlled trial comparing standard of care (once-weekly podiatric medical clinic visits) versus standard care plus adjunct Granulox therapy twice weekly in adults with foot ulcers. After a 2-week screening phase, patients in whom the index wound had healed by less than 50% were randomized 1:1. Outcome measures were collated during the trial phase at 6 and 12 weeks.

RESULTS

Of 79 patients enrolled, 38 were randomized. After 12 weeks, the median percentage wound size reduction compared with the size of the ulcer at the start of the trial phase was 100% for the control arm and 48% for the Granulox arm (P = .21, Mann-Whitney U test). In the former, eight of 14 foot ulcers had healed; in the latter, four of 15 (P = .14, Fisher exact test). In the control arm, two amputations and one withdrawal occurred, whereas in the Granulox arm, one unrelated death and five withdrawals were recorded.

CONCLUSIONS

We could not replicate the favorable healing associated with use of Granulox as published by others. Differences in wound chronicity and frequency of Granulox application might have influenced differences in study results. Granulox might perform best when used as an adjunct for treatment of chronic wounds at least 8 weeks old.

Photoacoustic imaging for the monitoring of local changes in oxygen saturation following an adrenaline injection in human forearm skin

Clinical monitoring of blood oxygen saturation (sO₂) is traditionally performed using optical techniques, such as pulse oximetry and diffuse reflectance spectroscopy (DRS), which lack spatial resolution. Photoacoustic imaging (PAI) is a rapidly developing biomedical imaging technique that is superior to previous techniques in that it combines optical excitation and acoustic detection, providing a map of chromophore distribution in the tissue. Hitherto, PAI has primarily been used in preclinical studies, and only a few studies have been performed in patients. Its ability to measure sO₂ with spatial resolution during local vasoconstriction after adrenaline injection has not yet been investigated. Using PAI and spectral unmixing we characterize the heterogeneous change in sO₂ after injecting a local anesthetic containing adrenaline into the dermis on the forearm of seven healthy subjects. In comparison to results obtained using DRS, we highlight contrasting results obtained between the two methods arising due to the so-called 'window effect' caused by a reduced blood flow in the superficial vascular plexus. The results demonstrate the importance of spatially resolving sO₂ and the ability of PAI to assess the tissue composition in different layers of the skin.

Systematic review of the efficacy of topical haemoglobin therapy for wound healing

Hypoxia is a common cause of poor wound healing, for which a variety of oxygen therapies have been developed. In order to overcome the limitations of traditional methods of treatment, namely the type of equipment, its setting, safety and cost, local haemoglobin therapy has been developed, although no reviews have so far been published. Here, we systematically review the current evidence to establish the efficacy, scope, adverse reactions, and required precautions of this new form of therapy. A search of the literature was conducted in the PubMed, Embase, Scopus, CENTRAL, CINAHL, and Web of science databases, with 17 studies meeting the eligibility criteria, comprising one animal model study and 16 clinical studies. Local haemoglobin therapy is able to safely and effectively promote the healing of a variety of wounds, especially those that are chronic and non-healing. However, premature discontinuation of this treatment can result in impediment to wound healing and even deterioration of the wound. The distinct benefit of the elimination of slough and relief of pain suggests that this technique may represent a new generation of debridement technology. Furthermore, its ease of use and convenience enables patient self-management, thereby greatly reducing health care costs.

Cost-effectiveness of adjunct haemoglobin spray in the treatment of hard-to-heal wounds in a UK NHS primary care setting

OBJECTIVE

To evaluate the cost-effectiveness of topical haemoglobin spray as adjunct therapy in the treatment of hard-to-heal wounds within a UK National Health Service (NHS) community setting.

METHOD

In a previously published comparative clinical evaluation, 50 consecutive patients treated with topical haemoglobin spray, as adjunct to standard care and followed up over 26 weeks, were compared with 50 consecutive retrospective controls from the same clinic treated with the same standard care protocol in the year prior to the introduction of adjunct topical haemoglobin spray. A de novo cost-effectiveness and break-even analysis were performed, using data from the previously published clinical evaluation, for all patients (intent-to-treat) and for patients with complete follow-up using a micro-costing approach and considering only wound care dressing costs.

RESULTS

At 26 weeks, the total cost of dressings for all patients in the intervention group was £6953 with 874 cumulative weeks healed, compared with £9547 with 278 cumulative weeks healed for all patients in the control group. The incremental cost-effectiveness ratio (ICER), the incremental cost per additional week healed with adjunct topical haemoglobin spray, is therefore negative (dominant). Total treatment costs per week were lower from week six onwards, with break-even estimated to be at week 10.2. When considering only patients with complete follow-up, the results were similarly dominant, with a mean 10.9 more weeks healed, a mean dressing cost saving per patient of £81.83 by week 26 (-37%). Cost savings were realised from week five, and a break-even was estimated to occur at week 8.0.

CONCLUSION

Topical haemoglobin spray has the potential to restore the healing process, reduce healing times and reduce dressing costs in a NHS community setting, within a few weeks of adoption.

A review of clinical photoacoustic imaging: Current and future trends

Photoacoustic imaging (or optoacoustic imaging) is an upcoming biomedical imaging modality availing the benefits of optical resolution and acoustic depth of penetration. With its capacity to offer structural, functional, molecular and kinetic information making use of either endogenous contrast agents like hemoglobin, lipid, melanin and water or a variety of exogenous contrast agents or both, PAI has demonstrated promising potential in a wide range of preclinical and clinical applications. This review provides an overview of the rapidly expanding clinical applications of photoacoustic imaging including breast imaging, dermatologic imaging, vascular imaging, carotid artery imaging, musculoskeletal imaging, gastrointestinal imaging and adipose tissue imaging and the future directives utilizing different configurations of photoacoustic imaging. Particular emphasis is placed on investigations performed on human or human specimens.

Topical application of haemoglobin: a safety study

OBJECTIVE

Ischaemia is one of the biggest problems in wound healing. It causes chronic wounds and also prevents normal wound healing because the tissue is oxygen deprived. Most oxygen-supplying therapies are only feasible in a clinical setting, but topical haemoglobin applications, such as Granulox, can be used in a non-clinical setting. For home application, the haemoglobin solution is sprayed topically onto the wound using a pressurised ready-to-use device with a bag-on-valve system. Although this system does not mix product and propellant, the risk of product inhalation by the patient, user or bystanders has to be minimised. This safety study aimed to determine particle size and product concentration in the surroundings after application to determine if there is a risk that product particles enter the respiratory tract.

METHODS

Measurements were performed using a laser scattered light photometer and a Scanning Mobility Particle Sizer (SMPS)-Spectrometer at different distances from the measuring devices to determine the inhalation risk for a possible user, patient and bystander. At all measuring points the amount of particles, their size and the formation of dust were measured.

RESULTS

No nanoparticles or dust were created during the application of the haemoglobin spray. The concentrations of the measured particles are below the allowed limits defined by Austrian law.

CONCLUSION

There is no risk of inhaling nanoparticles or being exposed to harmful concentrations of larger particles of the tested product. All the product's ingredients can be degraded and excreted by the human body through natural pathways.

Photoacoustic Oxygenation Quantification in Patients with Raynaud's: First-in-Human Results

The purpose of this study was to investigate the use of photoacoustic imaging for quantifying fingertip oxygenation as an approach to diagnosing and monitoring Raynaud's phenomenon. After 30 min of acclimation to room temperature, 22 patients (7 patients with secondary Raynaud's associated to Scleroderma and 15 healthy controls) provided informed consent to undergo fingertip Doppler imaging and high-frequency photoacoustic imaging before and 5, 15 and 30 min after cold stimulus (submerged hand in a 15 °C water bath for 1 min). High-frequency ultrasound and photoacoustic imaging was performed on the nail bed of each patient's second through fifth finger on their dominant hand, using a Vevo 2100 LAZR system with an LZ-250 probe (Fujifilm VisualSonics, Toronto, ON, Canada) in oxy-hemoglobin quantification mode. During each exam, volumetric data across a 3-mm span of data was acquired to produce a volumetric image of percent oxygenation and hemoglobin concentration. Changes in fingertip oxygenation between Raynaud's patients and healthy volunteers were compared, using receiver operator characteristic (ROC) analysis. Photoacoustic signal was detected in both the nail bed and nailfold in all study participants. Doppler ultrasound resulted in poor differentiation of Raynaud's patients from healthy volunteers, with an area under the ROC curve (A_z) of 0.51. Photoacoustic imaging demonstrated improved accuracy at baseline (A_z = 0.72), which improved when quantifying normalized changes after cold stimulus (A_z = 0.89 5-min post stimulus, A_z = 0.91 15-min post stimulus, and A_z = 0.85 after stimulus). Oxygenation levels derived using photoacoustic imaging are able to identify patients with Raynaud's and safely evaluate their response to a cold stimulus over time.