Guoan Zhang

Temperature distribution in the upper airway after inhalation injury

OBJECTIVE The aim of the study was to establish an animal model of laryngeal burn and to investigate the temperature distribution of heated air in the upper airway. METHODS The animal model was established by inhalation of dry heated air at 80, 160 and 320 °C in 18 healthy, male, adult hybrid dogs. Time for inducing injury was set at 20 min. The distribution of temperatures after heated-air inhalation was examined at different locations including the epiglottis, laryngeal vestibule, vocal folds and trachea. RESULTS The temperatures of the heated air decreased to 47.1, 118.4 and 193.8 °C at the laryngeal vestibule and to 39.3, 56.6 and 137.9 °C at the lower margin of vocal folds in the 80, 160 and 320 °C groups, respectively. CONCLUSION Due to its special anatomy and functions, the larynx has different responses to dry heated air at different temperatures. The air temperature decreases markedly when the air arrives at the larynx. By contrast, the larynx has a low capacity for blocking high-temperature air and retaining heat. As a result, high-temperature air often causes more severe injury to the larynx and the lower airway.

Firework injuries at a major trauma and burn center: A five-year prospective study

BACKGROUND AND OBJECTIVE In China, fireworks are an integral part of the celebration of the annual Spring Festival, but the number of injuries associated with their private use seen in emergency rooms increases dramatically. To raise awareness and help guide future prevention practices in this city, we investigated the epidemiology of firework-related injuries presented at our trauma and burn center in Beijing during the Spring Festivals of 2007-2011. METHODS Patients were interviewed using a pre-coded questionnaire to elicit information regarding age, gender, causes, injured body part, type of injury, diagnosis, and disposition. RESULT From 2007 to 2011, during the Spring Festivals 734 patients with fire-work related injuries were seen at our trauma and burn center in Beijing, the median patients of the five year were 140(136-150). The mean age of the patients was 26±15.3 years (range, 1-95 years). Of the 734 patients, the highest proportion of injuries were the 5-14 year-old age group The majority of the patients were male (87.9%), the overall male:female ratio was 7.41:1, and males were predominant in all age groups. For all 5 years, the incidence of firework-related injuries during the Spring Festival Holidays peaked specifically on the first, fifth, and last days, respectively. Injuries were mainly due to improper handling (415/610, 68.0%) or setting off illegal fireworks (195/610, 32.0%). The most frequently injured body parts were the hands and fingers (32.0%), head or face except eyes (28.3%), and trunk (22.4%). Burns were the most common type of injury (65.7%), most of the burned patients (437/453) were between 1% and 10%, and the most common region burned were hands and fingers (218/754). Contusions or lacerations were the second common type of injury (34.3%). Most of the patients (642, 87.5%) were treated and released, while 37 (5%) were treated and transferred, and 55 (7.5%) were admitted for advanced treatment. CONCLUSION The private use of fireworks during the Spring Festival Holidays is associated with a considerable number of injuries to various parts of the body. We can minimize the number and severity of accidents by raising awareness of safety practices, encouraging professional displays only and motivating manufacturers to adhere to strict quality control.

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 tissues 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.

Guidelines for burn rehabilitation in China

Quality of life and functional recovery after burn injury is the final goal of burn care, especially as most of burn patients survive the injury due to advanced medical science. However, dysfunction, disfigurement, contractures, psychological problems and other discomforts due to burns and the consequent scars are common, and physical therapy and occupational therapy provide alternative treatments for these problems of burn patients. This guideline, organized by the Chinese Burn Association and Chinese Association of Burn Surgeons aims to emphasize the importance of team work in burn care and provide a brief introduction of the outlines of physical and occupational therapies during burn treatment, which is suitable for the current medical circumstances of China. It can be used as the start of the tools for burn rehabilitation.

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.

Guideline for diagnosis, prophylaxis and treatment of invasive fungal infection post burn injury in China 2013

Invasive fungal infection is one of the major complication of severe burns which can induce local or systemic inflammatory response and cause serious substantial damage to the patient. The incidence of fungal infection for burn victims is increasing dramatically during recent years. This guideline, organized by Chinese Society of Burn Surgeons, aims to standardize the diagnosis, prevention and treatment of burn invasive fungal infection. It can be used as one of the tools for treatment of major burn patients.