The effect of hyperbaric oxygen treatment on a compromised axial pattern flap in the cat

A Co-MOF encapsulated microneedle patch activates hypoxia induction factor-1 to pre-protect transplanted flaps from distal ischemic necrosis

Avoiding ischemic necrosis after flap transplantation remains a significant clinical challenge. Developing an effective pretreatment method to promote flap survival postoperatively is crucial. Cobalt chloride (CoCl2) can increase cell tolerance to ischemia and hypoxia condition by stimulating hypoxia-inducible factor-1 (HIF-1) expression. However, the considerable toxic effects severely limit the clinical application of CoCl2. In this study, cobalt-based metal-organic frameworks (Co-MOF) encapsulated in a microneedle patch (Co-MOF@MN) was developed to facilitate the transdermal sustained release of Co2+ for rapid, minimally invasive rapid pretreatment of flap transplantation. The MN patch was composed of a fully methanol-based two-component cross-linked polymer formula, with a pyramid structure and high mechanical strength, which satisfied the purpose of penetrating the skin stratum corneum of rat back to achieve subcutaneous vascular area administration. Benefiting from the water-triggered disintegration of Co-MOF and the transdermal delivery via the MN patch, preoperative damage and side effects were effectively mitigated. Moreover, in both the oxygen-glucose deprivation/recovery (OGD/R) cell model and the rat dorsal perforator flap model, Co-MOF@MN activated the HIF-1α pathway and its associated downstream proteins, which reduced reperfusion oxidative damage, improved blood supply in choke areas, and increased flap survival rates post-transplantation. This preprotection strategy, combining MOF nanoparticles and the MN patch, meets the clinical demands for trauma minimization and uniform administration in flap transplantation. STATEMENT OF SIGNIFICANCE: Cobalt chloride (CoCl2) can stimulate the expression of hypoxia-inducible factor (HIF-1) and improve the tolerance of cells to ischemia and hypoxia conditions. However, the toxicity and narrow therapeutic window of CoCl2 severely limit its clinical application. Herein, we explored the role of Co-MOF as a biocompatible nanocage for sustained release of Co2+, showing the protective effect on vascular endothelial cells in the stress model of oxygen-glucose deprivation. To fit the clinical needs of minimal trauma in flap transplantation, a Co-MOF@MN system was developed to achieve local transdermal delivery at the choke area, significantly improving blood supply opening and flap survival rate. This strategy of two-step delivery of Co2+ realized the enhancement of biological functions while ensuring the biosafety.

Common Uses and Adverse Effects of Hyperbaric Oxygen Therapy in a Cohort of Small Animal Patients: A Retrospective Analysis of 2,792 Treatment Sessions

Hyperbaric oxygen therapy (HBOT) is commonly utilized for various human conditions with a low incidence of major adverse effects (0.002–0.035%). Despite growing use in veterinary patients, there remains a paucity of literature describing its use and associated complications. The purpose of this study was to report clinical use of HBOT in small animals and identify the rate of major adverse events at a university teaching hospital. Electronic medical records were searched for small animals receiving HBOT between November 2012 and February 2020. Data extracted from the medical records included signalment, treatment indication, and adverse events. Treatment sessions totaled 2,792 in 542 dogs, 24 cats, and 10 pocket pets and exotics. Common indications included neurologic injuries (50.4%), tissue healing (31.4%), control of oomycete infection (5.5%), neoplasia or post-radiation injury (5.4%), and various miscellaneous conditions (7.4%). Observed minor adverse events included agitation in two dogs and vomiting in three dogs. The most common major adverse event was central nervous system (CNS) oxygen toxicity in 19 dogs. Central nervous system oxygen toxicity, manifesting as focal or generalized seizures, occurred in 0.7% of treatment sessions, with increasing age (p = 0.01) and female sex (p = 0.01) identified as risk factors. One dog developed pulmonary edema following HBOT which is a reported adverse event in humans or may have been a manifestation of progression of the dog's underlying disease. No adverse events were noted in cats or other species. In conclusion, HBOT appeared safe across various indications, although oxygen toxicity affecting the CNS was higher than reports in humans. Future prospective, randomized, controlled trials should evaluate specific clinical indications and outcomes.

Safety and Tolerability of Hyperbaric Oxygen Therapy in Cats and Dogs

This prospective clinical trial was designed to evaluate the safety of hyperbaric oxygen therapy (HBOT) in a population of cats and dogs with a variety of naturally occurring diseases. Seventy-eight dogs and twelve cats with various naturally occurring disease conditions, who had the potential to benefit from HBOT, were enrolled in the study. These patients were treated with HBOT in a monoplace hyperbaric oxygen chamber at 2 air pressure absolute for a treatment length of either 45 min or 60 min. There were 230 hyperbaric oxygen treatments performed during the study period. No major adverse effects were observed. There were 76 minor adverse effects recorded, which were not considered to be of clinical significance. Hyperbaric oxygen therapy was well tolerated and there were no major adverse effects recorded during treatment.

Integrative veterinary medical education and consensus guidelines for an integrative veterinary medicine curriculum within veterinary colleges

Integrative veterinary medicine (IVM) describes the combination of complementary and alternative therapies with conventional care and is guided by the best available evidence. Veterinarians frequently encounter questions about complementary and alternative veterinary medicine (CAVM) in practice, and the general public has demonstrated increased interest in these areas for both human and animal health. Consequently, veterinary students should receive adequate exposure to the principles, theories, and current knowledge supporting or refuting such techniques. A proposed curriculum guideline would broadly introduce students to the objective evaluation of new veterinary treatments while increasing their preparation for responding to questions about IVM in clinical practice. Such a course should be evidence-based, unbiased, and unaffiliated with any particular CAVM advocacy or training group. All IVM courses require routine updating as new information becomes available. Controversies regarding IVM and CAVM must be addressed within the course and throughout the entire curriculum. Instructional honesty regarding the uncertainties in this emerging field is critical. Increased training of future veterinary professionals in IVM may produce an openness to new ideas that characterizes the scientific method and a willingness to pursue and incorporate evidence-based medicine in clinical practice with all therapies, including those presently regarded as integrative, complementary, or alternative.

An evidence-based appraisal of the use of hyperbaric oxygen on flaps and grafts

Hyperbaric oxygen has been advocated, both as an adjunctive or primary form of treatment, for a variety of disorders, including gas gangrene, osteoradionecrosis, and carbon monoxide poisoning. It has also been used to improve ischemic wounds before skin grafting and to support ischemic flaps. In this review, we analyze the available literature that investigates the use of hyperbaric oxygen for composite grafts, skin grafts, random flaps, distant flaps, and free flaps. An appraisal of the level of evidence for each of these uses of hyperbaric oxygen is offered. Although there are a significant amount of animal data supporting the application of hyperbaric oxygen for grafts and flaps, there is very little clinical information other than case reports and series to sustain its choice over other modalities of therapy. Multicenter prospective clinical studies are clearly needed comparing hyperbaric oxygen to other mechanical or pharmacologic interventions to improve wound healing for grafting or to support flap survival.

Simultaneous use of bilateral caudal superficial epigastric axial pattern flaps for wound closure in a dog

A neutered male German shorthaired pointer sustained severe bite wounds to the left caudal flank and thigh area. Thorough wound lavage and debridement was performed immediately and also three days after presentation. Daily wound dressing resulted in the production of a mature granulation tissue bed. Prior to wound closure, colour flow Doppler ultrasonography was used to confirm blood flow through the right and left caudal superficial epigastric arteries and veins. Sixteen days after presentation, right and left caudal superficial epigastric axial pattern flaps were simultaneously elevated to cover the defect. The right flap was elevated as an island flap, rotated 120 degrees and used to cover the caudodorsal aspect of the defect. The left flap was elevated and rotated dorsally to cover the cranioventral aspect of the defect. Ninety per cent wound coverage was achieved and flap survival was total. The donor site defect was closed primarily and no dehiscence occurred. Three months postsurgery, the entire defect was closed and limb function was normal.

Effect of hyperbaric oxygen therapy on the tubed pedicle flap survival in a rat model

The effect of hyperbaric oxygen therapy (HBO) on survival of the distal skin paddle with early pedicle division was studied in a rat tubed pedicle flap model. In part 1, tubed pedicle skin flaps were created on the backs of 14 rats. The pedicle of each skin flap was divided at intervals of 3, 4, 5, and 7 days, and the survival area of each distal skin paddle was measured 5 days after each pedicle was divided. The results showed that the percentages of survival were 0%, 29.9%, 89.9%, and 100% at 3, 4, 5, and 7 days, respectively. In part 2, the tube flaps were created on the backs of 28 rats. The tubed pedicles were divided 4 days after creation. In the experimental group 1 (n = 9), the rats received HBO treatment at 2 atm of pressure twice daily for 3 consecutive days before pedicle division. In the experimental group 2 (n = 9), the rats received HBO treatment after pedicle division twice daily for 3 consecutive days. In the control group (n = 10), the rats received no HBO treatment. The results showed that the mean survival area of the distal skin paddle at 5 days after pedicle division for the groups treated with HBO before and after pedicle division was 6.31 +/- 2.69 cm2 (69.19%) and 6.12 +/- 1.52 cm2 (71.22%), respectively. These survival rates were of statistical significance as compared with the survival rates in the control group of 2.70 +/- 1.89 cm2 (27.9%). These results demonstrate that the administration of HBO therapy to the animal with a tubed pedicle flap can increase flap survival with early division of the tubed pedicle.

Effect of hyperbaric oxygen on pedicle flaps with compromised circulation

The effect of hyperbaric oxygen (HBO) on the survival rate of experimental rat pedicle island flaps with arterial, venous, and combined arteriovenous insufficiency was evaluated. Forty male Wistar rats with pedicle island flaps were divided into four groups with different types of vascular status. Another 40 male Wistar rats, also divided into four groups, were reconstructed in the same manner, but were also exposed to HBO. The results were evaluated using a laser Doppler flowmeter and an estimation of the length of the surviving tissue of the flaps. In evaluations using Kruskal-Wallis test, there was a significant difference in the survival tissue length and mean LD flows among our four untreated groups (P < 0.05). We considered the experimental model defined by Tzusuki and colleagues suitable for our study. Using a Mann-Whitney test, the differences in flap tissue survival length between each type of vascular insufficiency of HBO-treated and untreated groups was significant (P < 0.05). This finding indicates that the survival length was directly improved by the HBO treatment for all type of vascular insufficiency. HBO treatment increased the percentage of survival length and mean LD flows of axial pattern skin flaps with all type of vascular insufficiency. This effect, however, was greatest in the arterial insufficiency flaps.

Use of omental pedicle grafts in the management of non-healing axillary wounds in 10 cats

A retrospective analysis of the clinical case histories of 10 domestic shorthaired cats that underwent omentalisation, using a vascular pedicle of greater omentum, of chronic non-healing axillary wounds was carried out. Wounds were debrided and closed in a primary fashion following omentalisation. The cats had undergone a modal number of three previous repair attempts over a three- to 18-month period (mean 11 months) before referral. Further dehiscence occurred in eight cases, requiring a modal number of one further attempt at closure of the wound. Other complications included incisional herniation (two cats), serous exudate from the axillary wound (two cats) and paracostal abscessation (one cat). Long-term cure was achieved in seven of the 10 cases, with wounds finally having healed at a mean of 24 days post-omentalisation. Chronic axillary wounds are particularly difficult to treat and there are no reports of consistently successful techniques for their repair. This report suggests that omentalisation of these wounds may be a step towards such a repair procedure.