[Influencing factors and their predictive value of skin graft survival after Meek grafting in severe burn patients].

Abstract

Objective: To investigate the influencing factors and their predictive value of skin graft survival after Meek grafting in severe burn patients. Methods: Totally 115 severe burn patients (95 males, 20 females, aged 1-74 years) who were conforming to the inclusion criteria received Meek grafting in the First Affiliated Hospital of Army Medical University (the Third Military Medical University) from January 2013 to December 2019, among whom a case-control study was conducted. The patients were divided into good skin survival group with skin graft survival rate≥70% (68 cases) and poor skin graft survival group with skin graft survival rate<70% (47 cases). The gender, age, body mass index, full-thickness burn area, burn index, complication of inhalation injury, time from injury to operation, preoperative cystatin C level, preoperative albumin level, preoperative neutrophil percentage, preoperative hemoglobin level, preoperative platelet count, and platelet count on the first, third, and fifth day after operation during the first Meek grafting of patients in the two groups after admission were recorded. The above indicators between the two groups were statistically analyzed with independent sample t test, Mann-Whitney U test, and chi-square test. The gender, age, body mass index, full-thickness burn area, burn index, complication of inhalation injury, time from injury to operation of patients in the two groups were performed with 1∶1 propensity score matching (PSM) to eliminate the differences in baseline data, and then the above indexes were recorded and analyzed again for the remaining patients in the two groups. The indexes with statistically significant differences between the two groups after 1∶1 PSM were selected for multivariate logistic regression analysis to screen the independent risk factors affecting the skin graft survival after Meek grafting in severe burn patients. The receiver operating characteristic (ROC) curve of independent risk factors for predicting poor skin graft survival after Meek grafting in severe burn patients after 1∶1 PSM was drawn, and the area under the curve, the optimal threshold, and the sensitivity and specificity under the optimal threshold were calculated.\xa0The patients were divided into independent risk factor>optimal threshold group and independent risk factor≤optimal threshold group, the chi square test was used to compare the incidence of poor skin graft survival after Meek grafting, and the relative risk of poor skin graft survival after Meek grafting was calculated. Results: Before 1∶1 PSM, there were no statistically significant differences in gender, age, body mass index, complication of inhalational injury, time from injury to operation, preoperative cystatin C level, preoperative albumin level, preoperative neutrophil percentage, preoperative hemoglobin level of patients between the two groups (P>0.05); the full-thickness burn area and burn index of patients in poor skin graft survival group were significantly higher than those in good skin graft survival group (Z=-2.672, -2.882, P<0.01); the preoperative platelet count and the platelet count on the first, third, and fifth day after operation of patients in poor skin graft survival group were significantly lower than those in good skin graft survival group (Z=-3.411, -3.050, -2.748, -2.686, P<0.01). After 1∶1 PSM, 46 cases were remained in each group. There were no statistically significant differences in gender, age, body mass index, full-thickness burn area, burn index complication of inhalational injury, time from injury to operation, preoperative cystatin C level, preoperative albumin level, preoperative neutrophil percentage, preoperative hemoglobin level of patients between the two groups of patients (P>0.05); the preoperative platelet count and the platelet count on the first, third, and fifth day after operation of patients in poor skin graft survival group were significantly lower than those in good skin graft survival group (Z=-3.428, -2.940, t=-2.427, -2.316, P<0.05 or P<0.01). Multivariate logistic regression analysis showed that only the preoperative platelet count was an independent risk factor affecting the skin graft survival after Meek grafting in severe burn patients (odds ratio=0.994, 95% confidence interval=0.989-0.998, P<0.01). The area under the ROC curve of preoperative platelet count predicting poor skin graft survival after Meek grafting in 92 patients was 0.707 (95% confidence interval=0.603-0.798, P<0.01), and the cutoff value of preoperative platelet count was 98×10(9)/L, with sensitivity of 54.3% and specificity of 78.3%. The incidence of poor skin survival after Meek grafting of patients in preoperative platelet count≤98×10(9)/L group was 71.4% (25/35), which was significantly higher than 36.8% (21/57) in preoperative platelet count>98×10(9)/L group (χ(2)=10.376, P<0.01). Compare with that in preoperative platelet count>98×10(9)/L group, patients in preoperative platelet count≤98×10(9)/L had a relative risk of poor skin graft survival after Meek grafting of 2.211 (95% confidence interval=1.263-3.870). Conclusions: Preoperative platelet count is an independent risk factor affecting the skin graft survival after Meek grafting in severe burn patients, and has a good predictive value. Meek grafting should be performed with caution when the preoperative platelet count of patients is≤98×10(9)/L.