Protection of laryngeal mucosa and function in laryngeal burns by heat absorption of perilaryngeal tissue.

OBJECTIVE: The laryngeal tissue carries most of the heat during inhalation injury. This study aims to explore the heat transfer process and the severity of injury inside laryngeal tissue by horizontally studying the temperature rise process at various anatomical layers of the larynx and observing the thermal damage in various parts of the upper respiratory tract. METHODS: The 12 healthy adult beagles were randomly divided into four groups, and inhaled room temperature air (control group), dry hot air of 80 °C (group I), 160 °C (group II), and 320 °C (group III) for 20 min, respectively. The temperature changes of the glottic mucosal surface, the inner surface of the thyroid cartilage, the external surface of the thyroid cartilage, and subcutaneous tissue were measured every minute. All animals were immediately sacrificed after injury, and pathological changes in various parts of laryngeal tissue were observed and evaluated under a microscope. RESULTS: After inhaling hot air of 80 °C, 160 °C and 320 °C, the increase of laryngeal temperature in each group was ΔT = 3.57 ± 0.25 °C, 7.83 ± 0.15 °C, 11.93 ± 0.21 °C. The tissue temperature was approximately uniformly distributed, and the difference was not statistically significant. The average laryngeal temperature-time curve showed that the laryngeal tissue temperature in group I and group II showed a trend of "first decrease and then increase", except that the temperature of group III directly increased with time. The prominent pathological changes after thermal burns mainly concluded necrosis of epithelial cells, loss of the mucosal layer, atrophy of submucosal glands, vasodilatation, erythrocytes exudation, and degeneration of chondrocytes. Mild degeneration of cartilage and muscle layers was also observed in mild thermal injury. Pathological scores indicated that the pathological severity of laryngeal burns increased significantly with the increase of temperature, and all layers of laryngeal tissue were seriously damaged by 320 °C hot air. CONCLUSIONS: The high efficiency of tissue heat conduction enabled the larynx to quickly transfer heat to the laryngeal periphery, and the heat-bearing capacity of perilaryngeal tissue has a certain degree of protective effect on laryngeal mucosa and function in mild to moderate inhalation injury. The laryngeal temperature distribution was in accordance with the pathological severity, and the pathological changes of laryngeal burns provided a theoretical basis for the early clinical manifestations and treatment of inhalation injury.

Injuries Associated With Electrical Flash Burns in Children Caused by E-bike Batteries.

The use of electric bicycles (e-bikes) has increased in China. Alongside this increased use of e-bikes, reports of injuries related to e-bikes have also increased. However, few studies have explored electrical burns from short circuits in e-bike batteries, especially among children. Our study aimed to describe the epidemiology and prognosis of e-bike-related electrical flash burns in children. This retrospective analysis examined the injury patterns and prognosis of flash burn injuries from e-bike batteries among children presenting to the emergency department of a hospital in northern China from 2009 to 2020. Data collected included demographics, mechanism of injury, time of injury, injury site, burn depth, healing time, and patient prognosis. During the study period, 82 children presented to our emergency department with these injuries (boys: n = 64, 78%; girls: n = 18, 22%). The children's mean age was 3.5 (2.5) years. Burns occurred in all months of the year but peaked from May to August (spring and summer). Most burns were to the fingers. All burns were minor injuries that healed within 2 weeks with wound care. With the growing popularity of e-bikes, electric flash burns among children caused by e-bike batteries are increasingly common. Doctors should be aware of this special injury type to offer the correct diagnosis and treatment and provide parents with appropriate information.

Island Perforator Muscle Flaps for Chronic Osteomyelitis of the Lower Extremities: A Retrospective Analysis of 21 Consecutive Cases.

BACKGROUND: One of the procedures for treating chronic osteomyelitis is the management of dead space resulting from aggressive débridement of the marrow cavity. To fill the void created by débridement, various muscle flaps have been recommended by many surgeons for their convenience and antiinfective properties. The objective of this study was to evaluate the efficacy of island perforator muscle flaps for the reconstruction of chronic osteomyelitis débridement defects of the lower extremities and provide indications for the selection of the muscle flap. METHODS: A retrospective review of consecutive patients with chronic osteomyelitis of the lower extremities who underwent reconstruction using the island perforator muscle flap procedure from 2015 through 2018 was conducted. Data were collected on characteristics of the patients, wound site, wound size, surgical procedure, muscle choice, and wound healing. RESULTS: For the 21 patients included in the study, all muscle flaps survived. Wounds healed completely within 4 weeks. No infection relapses were identified during the follow-up period of at least 12 months. Simple primary closure, with no additional incision in the donor site, was achieved in five patients. In eight patients, an additional incision was made to harvest a muscle flap, but both the wound and donor site were closed primarily. CONCLUSION: The results showed that the island perforator muscle flap is less invasive, easy to harvest, and effective, and can be a good choice for the management of dead space resulting from débridement for chronic osteomyelitis in the lower extremity. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, IV.

Possible indicators of amputation and insufficient perfusion after heat press injury: A retrospective study.

INTRODUCTION: Amputation outcome after heat press injury is associated with insufficient perfusion. We aimed to determine other risk factors for heat press injury and mechanisms of insufficient perfusion associated with amputation. METHODS: We retrospectively classified 120 inpatients into the emergency and clinic groups, with arrival time before and after 48 h of injury, respectively. We performed propensity score-match to identify significant variables and combine them with those previously identified. Patients with or without amputation were categorized in different subgroups according to arrival time and perfusion with receiver-operator-characteristic (ROC) curves. RESULTS: In the emergently insufficient perfusion subgroup, red blood cell distribution width of standard deviation (RDW-SD) was statistically different between patients without and with amputation (cutoff = 43 fL; specificity = 0.909). In the urgent group, neutrophil-lymphocyte-ratio (NLR) and relative lymphocyte count (L%) showed no association with perfusion, but was associated with amputation (NLR cutoff value = 3.12; sensitivity = 0.846). Differential leukocytes and related ratios (both groups), D-dimer (emergency group), and creatine kinase (CK) (clinic group) were also associated with insufficient perfusion. CONCLUSION: The study showed some correlations. Inflammation variables, D-dimer, and CK were associated with amputation and perfusion after heat press injury. Several factors were associated with amputation, including RDW-SD increase in insufficiently perfused patients within 48 h of injury, and NLR increase and L% decrease in patients after 48 h post-injury.

Simulation of the Velocity and Temperature Distribution of Inhalation Thermal Injury in a Human Upper Airway Model by Application of Computational Fluid Dynamics.

Inhalation injury is an important cause of death after thermal burns. This study was designed to simulate the velocity and temperature distribution of inhalation thermal injury in the upper airway in humans using computational fluid dynamics. Cervical computed tomography images of three Chinese adults were imported to Mimics software to produce three-dimensional models. After grids were established and boundary conditions were defined, the simulation time was set at 1 minute and the gas temperature was set to 80 to 320°C using ANSYS software (ANSYS, Canonsburg, PA) to simulate the velocity and temperature distribution of inhalation thermal injury. Cross-sections were cut at 2-mm intervals, and maximum airway temperature and velocity were recorded for each cross-section. The maximum velocity peaked in the lower part of the nasal cavity and then decreased with air flow. The velocities in the epiglottis and glottis were higher than those in the surrounding areas. Further, the maximum airway temperature decreased from the nasal cavity to the trachea. Computational fluid dynamics technology can be used to simulate the velocity and temperature distribution of inhaled heated air.

[A retrospective analysis of 5 cases of major burns treated by goat acellular dermal matrix combined with hyaluronic acid].

OBJECTIVE: To evaluate the clinical efficacy of the goat acellular dermal matrix combined with hyaluronic acid (h-GADM) in the treatment of major burns. METHODS: A retrospective analysis of 5 patients with major burns undergoing combines microskin and h-GADM grafting. All patients were male, aged 33 to 50 years, and mean burn area were 83% ± 11%, which III degree wounds 60% to 90%. After extensive burns patients admitted to hospital in accordance with conventional treatment processes included fluid resuscitation, airway management, wound management, infection control and other treatment. The patients received the surgery after the shock of spending and hemodynamically stable. Summarized the feasibility and operative techniques of the new method, and elaborated on details by a typical case as an example. RESULTS: All the 5 patients were survival, go through the shock period smoothly, not haven any serious complications as lung infection, wound sepsis, septicemia and kidney failure occurred. A total of nine mircoskin graft operations were undergoing and covered 17 limbs. The average time of the h-GADM desquamtion was (17.7 ± 2.7) days after operation, the hospitalization time was (115 ± 27) days. After (72 ± 6) days, the residual wound was less than 5% total body surface area. CONCLUSION: The h-GAMD can be a good alternative to cadaver skin in the treatment of major burns.

Measuring surface temperature and grading pathological changes of airway tissue in a canine model of inhalational thermal injury.

BACKGROUND: Airway tissue shows unexpected invulnerability to heated air. The mechanisms of this phenomenon are open to debate. OBJECTIVE: This study was designed to measure the surface temperatures at different locations of the airway, and to explore the relationship between the tissue's surface temperature and injury severity. METHOD: Twenty dogs were randomly divided into four groups, including three experimental groups (six dogs in each) to inhale heated air at 70-80 °C (group I), 150-160 °C (group II) and 310-320 °C (group III) and a control group (two dogs, only for histological observation). Injury time was 20 min. Mucosal surface temperatures of the epiglottis (point A), cricoid cartilage (point B) and lower trachea (point C) were measured. Dogs in group I-III were divided into three subgroups (two in each), to be assayed at 12, 24 and 36 h after injury, respectively. For each dog, four tissue parts (epiglottis, larynx, lower trachea and terminal bronchiole) were microscopically observed and graded according to an original pathological scoring system (score range: 0-27). RESULT: Surface temperatures of the airway mucosa increased slowly to 40.60±3.29 °C, and the highest peak temperature was 48.3 °C (group III, point A). The pathological score of burned tissues was 4.12±4.94 (0.0-18.0), suggesting slight to moderate injuries. Air temperature and airway location both influenced mucosal temperature and pathological scores very significantly, and there was a very significant positive correlation between tissue temperature and injury severity. CONCLUSION: Compared to the inhalational air hyperthermia, airway surface temperature was much lower, but was still positively correlated with thermal injury severity.

[Skin irritation and sensitization of swine acellular dermal matrix treated with hyaluronic acid].

OBJECTIVE: To evaluate the skin irritation and sensitization potential of the swine acellular dermal matrix treated with hyaluronic acid (SADM-HA). METHODS: (1) Skin irritation test. Twelve New Zealand rabbits were divided into SADM-HA group, allogeneic skin group, and (human) xeno-skin group according to the random number table, with 4 rabbits in each group. Four test sites were designed on the back of each rabbit. Two test sites of each rabbit in the three groups were covered with SADM-HA, allogeneic skin, and xeno-skin, respectively. Another test site was covered with gauze containing 200 g/L sodium dodecyl sulfate solution as positive control. The last test site was covered with gauze containing normal saline as negative control. The primary irritation index and cumulative irritation index of each material were calculated. (2) Skin closed-patch test. Sixty guinea pigs were used. Fifty-four guinea pigs were divided into SADM-HA group, allogeneic skin group, and (human) xeno-skin group according to the random number table, with 18 guinea pigs in each group. Twelve guinea pigs in each of the three groups were correspondingly induced and stimulated by SADM-HA, allogeneic skin, and xeno-skin, with 6 guinea pigs in each group treated with ethanol-soaked gauze to serve as negative control. The remaining 6 guinea pigs were treated with gauze containing 25% α-hexylcinnamaldehyde ethanol solution as positive control. The rating scales of Magnusson and Kligman were used to grade the condition of skin after being treated with above-mentioned materials to evaluate skin sensitivity to them at post stimulation hour 24 and 48. Data were processed with the non-parametric test of independent samples. RESULTS: (1) In the skin irritation test, the primary irritation indexes of the three dressings in SADM-HA group, allogeneic skin group, and xeno-skin group were respectively -0.04, 0.13, and 0.08. The cumulative irritation indexes of the three dressings in SADM-HA group, allogeneic skin group, and xeno-skin group were respectively 0.27, 0.10, and 0.25, which were close to those of negative control within the three groups. The skin irritation of each of the three materials was negligible. (2) In the skin closed-patch test, all scores of the three dressings in SADM-HA group, allogeneic skin group, and xeno-skin group were between 0 and 1. The scores of SADM-HA group and allogeneic skin group were close to those of negative control within the two groups (with U values respectively 188.00 and 90.00, P values both above 0.05). The differences were statistically significant between each material of the three groups and positive control (with U values respectively 19.00, 59.00, 21.50, P values all below 0.01). CONCLUSIONS: The SADM-HA is safe and reliable without skin irritation and sensitization, and it has encouraging prospect in clinical application.

Large-area burns with pandrug-resistant Pseudomonas aeruginosa infection and respiratory failure.

BACKGROUND: Infection due to pandrug-resistant Pseudomonas aeruginosa (PDRPA) has become a challenge in clinical practice. The aim of this research was to summarize the treatment of large-area burns (60% - 80%) with PDRPA infection and respiratory failure in our hospital over the last two years, and to explore a feasible treatment protocol for such patients. METHODS: We retrospectively analyzed the treatment of five patients with large-area burns accompanied by PDRPA infection and respiratory failure transferred to our hospital from burn units in hospitals in other Chinese cities from January 2008 to February 2010. Before PDRPA infection occurred, all five patients had open wounds with large areas of granulation because of the failure of surgery and dissolving of scar tissue; they had also undergone long-term administration of carbapenems. This therapy included ventilatory support, rigorous repair of wounds, and combined antibiotic therapy targeted at drug-resistance mechanisms, including carbapenems, ciprofloxacin, macrolide antibiotics and ß-lactamase inhibitors. RESULTS: Four patients recovered from burns and one died after therapy. CONCLUSIONS: First, compromised immunity caused by delayed healing of burn wounds in patients with large-area burns and long-term administration of carbapenems may be the important factors in the initiation and progression of PDRPA infection. Second, if targeted at drug-resistance mechanisms, combined antibiotic therapy using carbapenems, ciprofloxacin, macrolide antibiotics and ß-lactamase inhibitors could effectively control PDRPA infection. Third, although patients with large-area burns suffered respiratory failure and had high risks from anesthesia and surgery, only aggressive skin grafting with ventilatory support could control the infection and save lives. Patients may not be able to tolerate a long surgical procedure, so the duration of surgery should be minimized, and the frequency of surgery increased.