Establishment and application of the ten-fold rehydration formula for emergency resuscitation of pediatric patients after extensive burns / 中华烧伤杂志

Objective: To investigate the scientificity and feasibility of the ten-fold rehydration formula for emergency resuscitation of pediatric patients after extensive burns. Methods: A retrospective observational study was conducted. The total burn area of 30%-100% total body surface area (TBSA) and body weight of 6-50 kg in 433 pediatric patients (250 males and 183 females, aged 3 months to 14 years) with extensive burns who met the inclusion criteria and admitted to the burn departments of 72 Class A tertiary hospitals were collected. The 6 319 pairs of simulated data were constructed after pairing each body weight of 6-50 kg (programmed in steps of 0.5 kg) and each total burn area of 30%-100% TBSA (programmed in steps of 1%TBSA). They were put into three accepted pediatric rehydration formulae, namely the commonly used domestic pediatric rehydration formula for burn patients (hereinafter referred to as the domestic rehydration formula), the Galveston formula, and the Cincinnati formula, and the two rehydration formulae for pediatric emergency, namely the simplified resuscitation formula for emergency care of patients with extensive burns proposed by the World Health Organization's Technical Working Group on Burns (TWGB, hereinafter referred to as the TWGB formula) and the pediatric ten-fold rehydration formula proposed by the author of this article--rehydration rate (mL/h)=body weight (kg) × 10 (mL·kg-1·h-1) to calculate the rehydration rate within 8 h post injury (hereinafter referred to as the rehydration rate). The range of the results of the 3 accepted pediatric rehydration formulae ±20% were regarded as the reasonable rehydration rate, and the accuracy rates of rehydration rate calculated using the two pediatric emergency rehydration formulae were compared. Using the maximum burn areas (55% and 85% TBSA) corresponding to the reasonable rehydration rate calculated by the pediatric ten-fold rehydration formula at the body weight of 6 and 50 kg respectively, the total burn area of 30% to 100% TBSA was divided into 3 segments and the accuracy rates of the rehydration rate calculated using the 2 pediatric emergency rehydration formulae in each segment were compared. When neither of the rehydration rates calculated by the 2 pediatric emergency rehydration formulae was reasonable, the differences between the two rehydration rates were compared. The distribution of 433 pediatric patients in the 3 previous total burn area segments was counted and the accuracy rates of the rehydration rate calculated using the 2 pediatric emergency rehydration formulae were calculated and compared. Data were statistically analyzed with McNemar test. Results: Substitution of 6 319 pairs of simulated data showed that the accuracy rates of the rehydration rates calculated by the pediatric ten-fold rehydration formula was 73.92% (4 671/6 319), which was significantly higher than 4.02% (254/6 319) of the TWGB formula (χ2=6 490.88,P<0.05). When the total burn area was 30%-55% and 56%-85% TBSA, the accuracy rates of the rehydration rates calculated by the pediatric ten-fold rehydration formula were 100% (2 314/2 314) and 88.28% (2 357/2 670), respectively, which were significantly higher than 10.98% (254/2 314) and 0 (0/2 670) of the TWGB formula (with χ2 values of 3 712.49 and 4 227.97, respectively, P<0.05); when the total burn area was 86%-100% TBSA, the accuracy rates of the rehydration rates calculated by the pediatric ten-fold rehydration formula and the TWGB formula were 0 (0/1 335). When the rehydration rates calculated by the 2 pediatric emergency rehydration formulae were unreasonable, the rehydration rates calculated by the pediatric ten-fold rehydration formula were all higher than those of the TWGB formula. There were 93.07% (403/433), 5.77% (25/433), and 1.15% (5/433) patients in the 433 pediatric patients had total burn area of 30%-55%, 56%-85%, and 86%-100% TBSA, respectively, and the accuracy rate of the rehydration rate calculated using the pediatric ten-fold rehydration formula was 97.69% (423/433), which was significantly higher than 0 (0/433) of the TWGB formula (χ2=826.90, P<0.05). Conclusions: The application of the pediatric ten-fold rehydration formula to estimate the rehydration rate of pediatric patients after extensive burns is more accurate and convenient, superior to the TWGB formula, suitable for application by front-line healthcare workers that are not specialized in burns in pre-admission rescue of pediatric patients with extensive burns, and is worthy of promotion.

Establishment and application of the tenfold rehydration formula for emergency resuscitation of adult patients after extensive burns / 中华烧伤杂志

Objective: To explore the scientificity and feasibility of the tenfold rehydration formula for emergency resuscitation of adult patients after extensive burns. Methods: A retrospective observational study was conducted. The total burn area (30%-100% total body surface area (TBSA)) and body weight (45-135 kg) of 170 adult patients (135 males and 35 females, aged (42±14) years) with extensive burns admitted to the Fourth Medical Center of PLA General Hospital from December 2016 to December 2019 were collected. The 6 461 pairs of simulated data obtained after pairing each body weight in 45 to 135 kg (programmed in steps of 1 kg) with each area in 30% to 100% TBSA (programmed in steps of 1%TBSA) were plugged into four recognized rehydration formulas--Parkland's formula, Brooke's formula, the 304th PLA Hospital formula, and the Third Military Medical University formula and two emergency rehydration formulas--the simplified first aid resuscitation plan for extensive burn patients proposed by the World Health Organization's Technical Working Group on Burns (TWGB, hereinafter referred to as the TWGB formula) and the tenfold rehydration formula proposed by the author of this article to calculate the rehydration rate within 8 hours after injury (hereinafter referred to as the rehydration rate), with results being displayed by a programming step of 10%TBSA for the total burn area. Taking the calculation results of four recognized rehydration formulas as the reasonable rehydration rate, the accuracy of rehydration rates calculated by two emergency rehydration formulas were calculated and compared. The body weight of 45-135 kg was divided into three segments by the results of maximum body weight at a reasonable rehydration rate calculated by the tenfold rehydration formula when the total burn area was 30% and 100% TBSA, respectively. The accuracy of rehydration rate calculated by two emergency rehydration formulas in each body weight segment was compared. When the rehydration rates calculated by two emergency rehydration formulas were unreasonable, the differences in rehydration rates between the two were compared. Statistical distribution of the aforementioned three body weight segments in the aforementioned 170 patients was counted. Using the total burn area and body weight data of the aforementioned 170 patients, the accuracy of rehydration rate calculated by two emergency rehydration formulas was calculated and compared as before. Data were statistically analyzed with McNemar test. Results: When the total burn area was 30%, 40%, 50%, 60%, 70%, 80%, 90%, and 100% TBSA, respectively, and the body weight was 45-135 kg, the rehydration rates calculated by two emergency rehydration formulas did not exceed the maximum of the calculated results of four recognized rehydration formulas; the rehydration rate calculated by the TWGB formula did not change accordingly with total burn area, while the rehydration rate calculated by the tenfold rehydration formula did not change accordingly with body weight. Substituting 6 461 pairs of simulated data showed that the accuracy of rehydration rate calculated by the tenfold rehydration formula was 43.09% (2 784/6 461), which was significantly higher than 2.07% (134/6 461) of the TWGB formula, χ2=2 404.80, P<0.01. When the body weights were 45-62 kg and 63-93 kg, the accuracy rates of rehydration rate calculated by the tenfold rehydration formula were 100% (1 278/1 278) and 68.42% (1 506/2 201), respectively, which were significantly higher than 0 (0/1 278) and 0.05% (1/2 201) of the TWGB formula, χ2=1 276.00, 1 501.01, P<0.01; when the body weight was 94-135 kg, the accuracy rate of rehydration rate calculated by the tenfold rehydration formula was 0 (0/2 982), which was significantly lower than 4.46% (133/2 982) of the TWGB formula, χ2=131.01, P<0.01. When the rehydration rates calculated by two emergency rehydration formulas were both unreasonable, the rehydration rate calculated by the tenfold rehydration formula was greater than that calculated by the TWGB formula in most cases, accounting for 79.3% (2 808/3 543). Among the 170 patients, the proportions of those weighing 45-62, 63-93, and 94-135 kg were 25.29% (43/170), 65.88% (112/170), and 8.82% (15/170), respectively. Among the 170 patients, the accuracy rate of rehydration rate calculated by the tenfold rehydration formula was 69.41% (118/170), which was significantly higher than 3.53% (6/170) of the TWGB formula, χ2=99.36, P<0.01. Conclusions: Applying the tenfold rehydration formula to calculate the emergency rehydration rate in adults after extensive burns is simpler than four recognized rehydration formulas, and is superior to the TWGB formula. The tenfold rehydration formula is suitable for the front-line medical staffs that are not specialized in burns in pre-admission rescue of adult patients with extensive burns, which is worth popularizing.

Effects of methacrylic anhydride gelatin hydrogel loaded with silver and recombinant human basic fibroblast growth factor on deep partial-thickness burn wounds in rabbits / 中华烧伤杂志

Objective: To investigate the effects of methacrylic anhydride gelatin (GelMA) hydrogel loaded with silver and recombinant human basic fibroblast growth factor (rh-bFGF) on deep partial-thickness burn wounds in rabbits. Methods: The experimental research method was adopted. Low-concentration GelMA materials, medium-concentration GelMA materials and high-concentration GelMA materials containing different concentrations of methacrylic anhydride (MA) were prepared, after adding photoinitiator, low-concentration GelMA hydrogels, medium-concentration GelMA hydrogels, and high-concentration GelMA hydrogels were obtained, respectively. The nuclear magnetic resonance spectroscopy was performed to detect the hydrogen nuclear magnetic resonance spectra of the above-mentioned three concentrations of GelMA materials, and to calculate the degree of substitution according to the spectrum diagram. The three-dimensional microstructure and pore size of 3 types of above-mentioned GelMA hydrogels were detected by field emission scanning electron microscopy (FESEM), with 9 samples measured. According to the selected concentration of MA, ten kinds of solutions of GelMA with different concentration of silver (silver-containing GelMA) were synthesized, and the silver-containing GelMA solution of each concentration was divided into three parts, and then exposed to ultraviolet light lasting for 20, 25, and 35 s, respectively. After adding photoinitiator,the corresponding silver-containing GelMA hydrogels were obtained. The residual degradation rate of silver-containing GelMA hydrogel with different photocrosslinking times was detected by collagenase degradation method at degradation of 12, 24, 36, and 48 h; and the time required for complete degradation was detected, and the sample number was 5. The inhibition zone diameter of GelMA hydrogel under above screened photocrosslinking times containing 10 concentrations of silver against Staphylococcus aureus was measured to reflect its antibacterial ability, and the sample numbers were all 5. The silver-containing GelMA hydrogel with statistical significance compared with the antibacterial circle diameter of the silver-containing GelMA hydrogel containing the lowest concentration (no silver) was considered as having antibacterial activity. The three-dimensional microstructure and pore size of the silver-containing GelMA hydrogels with antibacterial activity and the lowest drug concentration selected were detected by FESEM, and the sample numbers were all 9. The freeze-dried alone GelMA hydrogel and the freeze-dried silver-containing GelMA hydrogel were soaked in phosphate buffer solution for 24 h, respectively, then the swelling rate of the two GelMA hydrogel were calculated and compared by weighing method, and the sample number was 5. GelMA hydrogel containing silver and rh-bFGF, namely compound hydrogel for short, was prepared according to the preliminary experiment and the above experimental results. The appearance of the composite hydrogel was observed in general, and its three-dimensional microstructure and pore size were detected by FESEM. The deep partial-thickness burn wound was made on the back of 30 rabbits (aged 4-6 months, female half and half). Meanwhile, with the rabbit head as the benchmark, the wounds on the left side of the spine were treated as composite hydrogel treatment group, and the wounds on the right side were treated as gauze control group, and which were treated accordingly. On post injury day (PID) 3, 7, 14, 21, and 28, the healing of wounds in the two groups was observed. On PID 7, 14, 21, and 28, the wound healing area was recorded and the healing rate was calculated, with a sample number of 30. Data were statistically analyzed with analysis of variance for repeated measurement, one-way analysis of variance, and independent sample t test. Results: The substitution degree among low-concentration GelMA materials, medium-concentration GelMA materials, and high-concentration GelMA materials was significantly different (F=1 628.00, P<0.01). The low-concentration GelMA hydrogel had a loose and irregular three-dimensional spatial network structure with a pore size of (60±17) μm; the medium-concentration GelMA hydrogel had a relatively uniform three-dimensional spatial network and pore size with a pore size of (45±13) μm; the high-concentration GelMA hydrogel had the dense and disordered three-dimensional spatial network with a pore size of (25±15) μm, the pore sizes of 3 types of GelMA hydrogels were significantly differences (F=12.20, P<0.01), and medium concentration of MA was selected for the concentration of subsequent materials. The degradability of silver-containing GelMA hydrogels with different concentrations of the same photocrosslinking time was basically same. The degradation residual rates of silver-containing GelMA hydrogels with 20, 25, and 35 s crosslinking time at 12 h were (74.2±1.7)%, (85.3±0.9)%, and (93.2±1.2)%, respectively; the residual rates of degradation at 24 h were (58.3±2.1)%, (65.2±1.8)%, and (81.4±2.6)%, respectively; the residual rates of degradation at 36 h were (22.4±1.9)%, (45.2±1.7)%, and (68.1±1.4)%, respectively; the residual rates of degradation at 48 h were (8.2±1.7)%, (32.4±1.3)%, and (54.3±2.2)%, respectively, and 20, 25, and 30 s photocrosslinking time required for complete degradation of silver-containing GelMA hydrogels were (50.2±2.4), (62.4±1.4), and (72.2±3.2) h, and the difference was statistically significant (F=182.40, P<0.01), 25 s were selected as the subsequent photocrosslinking time. The antibacterial diameters of 10 types of silver-containing GelMA hydrogels against Staphylococcus aureus from low to high concentrations were (2.6±0.4), (2.5±0.4), (3.2±0.4), (12.1±0.7), (14.8±0.7), (15.1±0.5), (16.2±0.6), (16.7±0.5), (16.7±0.4), and (16.7±0.6) mm, respectively, and which basically showed a concentration-dependent increasing trend, and the overall difference was statistically significant (F=428.70, P<0.01). Compared with the silver-containing GelMA hydrogel with the lowest concentration, the antibacterial circle diameters of other silver-containing GelMA hydrogels with antibacterial ability from low to high concentration were significantly increased (with t values of 26.35, 33.84, 43.65, 42.17, 49.24, 55.74, and 43.72, respectively, P<0.01). The silver-containing GelMA hydrogel with the antibacterial diameter of (12.1±0.7) mm had the lowest antibacterial activity against Staphylococcus aureus and the lowest drug loading concentration, and the concentration of silver was selected for the concentration of subsequent materials. The microscopic morphology of the silver-containing GelMA hydrogel containing silver element with a pore size of (45±13) μm had a regular and linear strip-like structure. After soaking for 24 h, the swelling ratio of silver-containing GelMA hydrogel was similar to that of alone GelMA hydrogel. The composite hydrogel was colorless, clear and transparent, and its three-dimensional microstructure was a regular and uniform grid, with a filament network structure inside, and the pore size of (40±21) μm. On PID 3, a large amount of necrotic tissue and exudate of rabbit wound in composite hydrogel group were observed, and scattered scabs, a small amount of necrotic tissue and exudate of rabbit wound in gauze control group were observed. On PID 7, the area of rabbit wound in composite hydrogel group was significantly reduced, and adhesion of rabbit wound and gauze in gauze control group was observed. On PID 14, In composite hydrogel group, the rabbit wound surface was ruddy, and the growth of granulation tissue was observed, and in gauze control group, the rabbit wound base was pale, and the blood supply was poor. On PID 21, the rabbit wounds in composite hydrogel group healed completely, and rabbit wound in gauze control group had healing trend. On PID 28, new hair could be seen on rabbit wound surface in composite hydrogel group; oval wound of rabbit in gauze control group still remained. On PID 7, 14, 21, and 28, the wound healing areas of rabbit in composite hydrogel group were significantly larger than those in gauze control group (with t values of 2.24, 4.43, 7.67, and 7.69, respectively, P<0.05 or P<0.01). Conclusions: The medium-concentration GelMA hydrogel has good physical and chemical properties in terms of swelling and degradability. The screened silver-containing GelMA hydrogels had the lowest antibacterial activity and the lowest drug loading concentration. Composite hydrogel can significantly shorten the healing time of deep partial-thickness burn wounds in rabbits.

Application prospects of compound gelatin-methacryloyl hydrogel in bone tissue engineering / 中国组织工程研究

BACKGROUND: Compound gelatin-methacryloyl (GelMA) hydrogel has been shown to have unique advantages in bone, cartilage, myocardium, and vascular regeneration.OBJECTIVE: To summarize the novel progress of compound GelMA hydrogel for bone tissue engineering. METHODS: PubMed database and CNKI database from 2010 to 2017 were searched by using the keywords of "gelatin, methacrylamide, hydrogel, hydroxyapatite, bone tissue engineering, bone regeneration, seed cells, microenvironment" in Chinese and English, respectively. RESULTS AND CONCLUSION: Inorganic components can be added in a specific way into the compound GelMA hydrogel to prepare tissue-engineered bone using photolithography, microfluidics, microfabrication and 3D printing techniques. The prepared tissue-engineered bone has similar structural, mechanical and biological properties to natural bone tissue, and importantly, it has osteogenic ability. Gene-modified seed cells that are co-cultured with the compound GelMA hydrogel in a 3D environment are found to grow well and express some genes related to bone regeneration and vascular regeneration. Therefore, the compound GelMA hydrogel has a good osteogenesis effect in vitro,which is an excellent material for bone tissue engineering.

Properties of geIatin methacryIoyI and its appIication in the skin tissue engineering / 中国组织工程研究

BACKGROUND: Gelatin methacryloyl has been widely used in the field of tissue engineering, as it has suitable biological properties, tunable physical and chemical properties, non-cytotoxic and non-immunogenicity.OBJECTIVE: To summarize the latest advances in the repair of skin and soft tissue damage using gelatin methacryl hydrogel materials. METHODS: PubMed and SciFinder were retrieved for articles concerning gelatin methacrylate hydrogels published from January 2007 to August 2017. The key words were "seed cell, skin regeneration, wound vascularization, gelatin, gelatin methacryloyl, scaffold material, wound healing, microenvironment, tissue construction, skin tissue engineering". RESULTS AND CONCLUSION: The gelatin methacryloyl hydrogel is very similar to the native extracellular matrix, and has a cell adhesion site, a matrix metalloproteinase-reactive peptide-based sequence and a cross-linkable property exhibiting good tissue affinity. The hydrogel has adjustable physical and chemical properties, a certain degree of adhesion and biodegradability, which make it an ideal cell scaffold, allowing all kinds of cells to proliferate and extend on its surface. Therefore, gelatin methacrylamide hydrogel has broad prospects in the skin tissue engineering, which can accelerate wound vascularization and epithelial tissue regeneration, improve wound healing rate, reduce the probability of infection, and improve the patient's quality life. The gelatin methacrylamide hydrogen is proved to provide an efficient and portable gel dressing for burn wounds and war wounds, and it can also be used to fill skin and soft tissue defects such as trauma and ulcers, and cover cosmetic incisions.

The relation between serum cholinesterase level and both the disease progress and prognosis of massively burned patients:a retrospective study / 解放军医学杂志

Objective To observe the dynamic change of serum cholinesterase (ChE) activity in severely burned patients,analyze the correlation between serum cholinesterase activity and both the severity and prognosis of burn injury.Methods The clinical data of 203 patients with large area burn (TBSA ＞30％) were collected from the Department of Burns and Plastic Surgery,First Affiliated Hospital of PLA General Hospital from January 2014 to December 2016 and the data of 30 healthy subjects as control group were retrospectively analyzed.According to the total burn area,these patients were divided into 3 groups:30％-49％ TBSA group (n=77),50％-79％ TBSA group (n=70),more than 80％ TBSA group (n=56).The serum was extracted from the two groups at 1,3,5,7,9,11,14,21,28,35 and 42 days after injury.Serum ChE activity was compared between the patients and the controls,and between the patient groups.The comparisons were also conducted between the 3 patient groups on the altitude of the decrease in serum ChE activity 21 days after injury,when the serum ChE activity reached the lowest level after injury,and the correlation between the burn area and the serum ChE activity was analyzed at each time point.In addition,according to the prognosis,the patients were divided into the survival group (n=172) and the death group (n=31).The serum ChE activity at each time point and the range of serum ChE activity decrease on day 21 and day 28 after injurywere compared between the two groups.Results 1)The serum ChE activity was lower in the patient groups than in the control group (8.18 ± 1.15kU/L) at all the time points observed except the first day after injury (P＜0.01).2) On the 21st and 28th days after injury,the serum AhE activity was higher in 30％-49％TBSA group than in the 50％-79％ TBSA group and in ≥ 80％ TBSA group,and the activity was higher in 50％-79％ TBSA group than in ≥ 80％ TBSA group (P＜0.05).Pearson correlation analysis on the serum ChE activity and burn area showed a significant positive correlation on day 3,5 and 7 after injury (P＜0.01) and a significant negative correlation on day 14,21 and 28 day after the injury (P＜0.05,P＜0.01),and no significant correlation at the remaining time points (P＞0.05).Up to the 21st day after injury,serum ChE decreased less significantly in 30％-49％ TBSA group (1.18 ± 1.70kU/L) than in 50％-79％ TBSA group (2.20 ± 2.01kU/L)and in ≥80％ TBSA group (3.35 ± 1.89kU/L),and less significantly in 50％-79％ TBSA group than in ≥80％ TBSA group,with statistically significant differences (P＜0.05).3) The serum ChE activity decreased to the lowest value (4.89 ± 1.48kU/L) on day 21 after burn in the survival group and to the lowest value (4.21 ± 1.37kU/L) on day 28 in the death group,with statistically significant difference (P＜0.05).On day 28 after injury,the serum ChE activity was significantly higher (4.92 ± 1.46kU/L) in the survival patients than in the patients died (4.21 ± 1.37kU/L) at the 21st day after injury.On day 21 and 28 after injury,the magnitude of decrease in serum ChE activity was less significant in the survival group (2.26 ± 1.93kU/L and 2.43 ± 1.87kU/L respectively) than in the death group (3.61 ± 2.20kU/L and 4.22 ± 1.94kU/L) (P＜0.05).Conclusions After burn,the activity of serum ChE decreased significantly,and there was a tendency to decrease firstly and increase aftetwards.The activity reached the lowest value on day 21 after injury.The area of burn was negatively correlated with the activity of serum ChE,and this relation was more remarkable on day 14,21 and 28 after injury.The greater the decrease of serum ChE activity,the worse the prognosis of the patients.As such,serum ChE activity has a certain value in reflecting the severity of burn injury and predicting the prognosis of patients.