AIM: To analyse the data on inpatients undergoing elective abdominal surgery to identify risk factors and develop predictive models that will help clinicians assess patients preoperatively.
METHODS: We retrospectively analysed the inpatient records of Shaanxi Provincial People's Hospital from January 1, 2018 to January 1, 2021. We included the demographic data of the patients and their haematological test results in our analysis. The attending physicians provided the Nutritional Risk Screening 2002 (NRS 2002) scores. The surgeons and anaesthesiologists manually calculated the National Nosocomial Infections Surveillance (NNIS) scores. Inpatient SSI risk factors were evaluated using univariate analysis and multivariate logistic regression. Nomograms were used in the predictive models. The receiver operating characteristic and area under the curve values were used to measure the specificity and accuracy of the model.
RESULTS: A total of 3018 patients met the inclusion criteria. The surgical sites included the uterus (42.2%), the liver (27.6%), the gastrointestinal tract (19.1%), the appendix (5.9%), the kidney (3.7%), and the groin area (1.4%). SSI occurred in 5% of the patients (n = 150). The risk factors associated with SSI were as follows: Age; gender; marital status; place of residence; history of diabetes; surgical season; surgical site; NRS 2002 score; preoperative white blood cell, procalcitonin (PCT), albumin, and low-density lipoprotein cholesterol (LDL) levels; preoperative antibiotic use; anaesthesia method; incision grade; NNIS score; intraoperative blood loss; intraoperative drainage tube placement; surgical operation items. Multivariate logistic regression revealed the following independent risk factors: A history of diabetes [odds ratio (OR) = 5.698, 95% confidence interval (CI): 3.305-9.825, P = 0.001], antibiotic use (OR = 14.977, 95%CI: 2.865-78.299, P = 0.001), an NRS 2002 score of ≥ 3 (OR = 2.426, 95%CI: 1.199-4.909, P = 0.014), general anaesthesia (OR = 3.334, 95%CI: 1.134-9.806, P = 0.029), an NNIS score of ≥ 2 (OR = 2.362, 95%CI: 1.019-5.476, P = 0.045), PCT ≥ 0.05 μg/L (OR = 1.687, 95%CI: 1.056-2.695, P = 0.029), LDL < 3.37 mmol/L (OR = 1.719, 95%CI: 1.039-2.842, P = 0.035), intraoperative blood loss ≥ 200 mL (OR = 29.026, 95%CI: 13.751-61.266, P < 0.001), surgical season (P < 0.05), surgical site (P < 0.05), and incision grade I or III (P < 0.05). The overall area under the receiver operating characteristic curve of the predictive model was 0.926, which is significantly higher than the NNIS score (0.662).
CONCLUSION: The patient's condition and haematological test indicators form the bases of our prediction model. It is a novel, efficient, and highly accurate predictive model for preventing postoperative SSI, thereby improving the prognosis in patients undergoing abdominal surgery.
METHODS: The chloroplast ultrastructure of 76 Selaginella species was studied with various microscopic techniques. Environmental data for selected species and subgeneric relationships were compared against chloroplast traits.
RESULTS: We delineated five chloroplast categories: ME (monoplastidy in a dorsal epidermal cell), MM (monoplastidy in a mesophyll cell), OL (oligoplastidy), Mu (multiplastidy, present in the most basal species), and RC (reduced or vestigial chloroplasts). Of 44 ME species, 11 have bizonoplasts, cup-shaped (concave upper zone) or bilobed (basal hinge, a new discovery), with upper zones of parallel thylakoid membranes varying subtly between species. Monoplastidy, found in 49 species, is strongly shade associated. Bizonoplasts are only known in deep-shade species (<2.1% full sunlight) of subgenus Stachygynandrum but in both the Old and New Worlds.
CONCLUSIONS: Multiplastidic chloroplasts are most likely basal, implying that monoplastidy and bizonoplasts are derived traits, with monoplastidy evolving at least twice, potentially as an adaptation to low light. Although there is insufficient information to understand the adaptive significance of the numerous structural variants, they are unmatched in the vascular plants, suggesting unusual evolutionary flexibility in this ancient plant genus.