화상 환자의 수술 후 합병증과 위험 인자

Abstract

Background: Burn injury can induce renal and cardiovascular complications and even mortality. The neutrophil/lymphocyte ratio (NLR) is an indicator of systemic inflammation, and the prognostic nutritional index (PNI) is related to perioperative nutritional status. Also, the De Ritis ratio, defined as aspartate aminotransferase-to-alanine aminotransferase ratio, can be used to predict the mortality of various cancers. However, little is known about the predictive ability of NLR, PNI, and De Ritis ratio for poor postoperative outcomes in patients with burn injury. Therefore, in the following three parts, the author elucidates the evaluation of risk factors for poor postoperative outcomes such as occurrence of acute kidney injury (AKI), major adverse cardiac events (MACE), and mortality in patients who underwent burn surgery.

PART 1 Objective: The author evaluated the risk factors for postoperative occurrence of AKI in patients with burn injury. Methods: Data on preoperative, intraoperative, and postoperative variables of patients with burn injury were collected. Risk factors for occurrence of AKI after burn surgery were evaluated using univariate and multivariate logistic regression analyses. A receiver operating characteristic (ROC) curve analysis of the preoperative NLR was performed. After surgery, the 3-month mortality rate was also compared between the AKI and non-AKI groups using the Kaplan-Meier method with a log-rank test. Results: Postoperative AKI occurred in 71 out of 473 (15.0%) patients with burn injury. Preoperative NLR (odds ratio [OR] = 1.094; 95% confidence interval [CI] = 1.064–1.125; P <0.001), total body surface area (TBSA) burned (OR = 1.013; 95% CI = 1.001–1.026; P = 0.037), and inhalation injury (OR = 1.821; 95% CI = 1.008–3.292; P = 0.047) were risk factors for occurrence of AKI after surgery. The area under the ROC curve of preoperative NLR was 0.767, with an optimal cut-off value of 11.7. Moreover, the 3-month mortality after surgery was significantly higher in the AKI group than in the non-AKI group (49.3% vs. 14.9%, P <0.001). Conclusion: Preoperative NLR was a risk factor for occurrence of AKI after burn surgery, which is associated with early postoperative mortality. Preoperative NLR can provide useful information for the early detection of postoperative AKI and prevent subsequent mortality in patients with burn injury.

PART 2 Objective: The author evaluated the impact of preoperative PNI on the incidence of MACE after burn surgery. Methods: The study included patients who were admitted to the burn intensive care unit before undergoing burn surgery. PNI was calculated as 10 × serum albumin level (g/dL) + 0.005 × total lymphocyte count (per mm3). A multivariate logistic regression analysis was performed to evaluate the risk factors for occurrence of MACE six months after burn surgery. An ROC curve analysis of PNI was performed, and a propensity score-matched analysis was performed to evaluate the impact of PNI on MACE. A Kaplan-Meier analysis was performed to compare postoperative 1-year mortality between the MACE and non-MACE groups. Results: MACE after burn surgery occurred in 184 (17.5%) out of 1049 patients. Preoperative PNI, age, American Society of Anesthesiologists (ASA) physical status, and TBSA burned were significantly associated with occurrence of MACE. The area under the ROC curve of preoperative PNI was 0.729 (optimal cut-off value = 35). After propensity score matching, the incidence of MACE in the PNI <35 group was significantly higher than that in the PNI ≥35 group (20.1% vs. 9.6%, P <0.001), and PNI <35 was associated with an increased incidence of MACE (OR = 2.373, 95% CI = 1.499–3.757, P <0.001). The postoperative 1-year mortality was significantly higher in the MACE group than in the non-MACE group (54.9% vs. 9.1%, P <0.001). Conclusion: Preoperative PNI was a risk factor for the incidence of MACE after burn surgery. PNI <35 was significantly associated with an increased incidence of MACE. In addition, MACE was associated with a high postoperative 1-year mortality.

PART 3 Objective: The author evaluated risk factors, including the De Ritis ratio, associated with 1-year mortality after burn surgery. Methods: Patients who underwent burn surgery from 2009 to 2019 were retrospectively evaluated. The De Ritis ratio was defined as aspartate aminotransferase-to-alanine aminotransferase ratio. Multivariate Cox regression analysis was conducted to evaluate the risk factors for 1-year mortality after burn surgery. Receiver operating characteristic (ROC) curve analysis of the De Ritis ratio was performed to predict postoperative 1-year mortality. Kaplan–Meier survival analysis was also conducted. Other postoperative outcomes, such as durations of hospital and intensive care unit stays, AKI, and MACE, were evaluated. Results: One-year mortality after burn surgery occurred in 247 (19.9%) of 1244 patients. The risk factors for 1-year mortality after burn surgery were the De Ritis ratio, age, American Society of Anesthesiologists physical status, diabetes mellitus, total body surface area burned, inhalation injury, serum creatinine level, and serum albumin level. The area under the ROC curve for the De Ritis ratio was 0.716 (optimal cutoff = 1.9). The 1-year mortality rate after burn surgery was significantly higher in patients with a De Ritis ratio >1.9 than in those with a De Ritis ratio ≤1.9 (35.8% vs. 11.8%, P <0.001). The survival rate was significantly higher in patients with a De Ritis ratio ≤1.9 than in those with a De Ritis ratio >1.9 (log-rank test, P <0.001). Intensive care unit stay, acute kidney injury, and major adverse cardiac events were significantly higher in patients with a De Ritis ratio >1.9 than in those with a De Ritis ratio ≤1.9 (P = 0.006, P <0.001, and P <0.001, respectively). Conclusion: The preoperative De Ritis ratio was a risk factor for 1-year mortality after burn surgery. The De Ritis ratio >1.9 was significantly associated with an increased 1-year mortality after burn surgery. These findings emphasized the importance of identifying burn patients with an increased De Ritis ratio to reduce the mortality after burn surgery.