Objectives To study the role of the kidney in the maintenance of metabolic alkalosis of critically ill patients during perioperative period.Methods The patients who had metabolic alkalosis in the surgical intensive care unite（SICU） from Nov 2004 to Feb 2005 were enrolled in the alkalosis group；and the control group were the perioperative patients in the department of hepatic surgery at the same time，those who had acid-base imbalance were excluded.The enrolled patients underwent routine tests and some parameters such as creatinine clearance rate（Ccr，to evaluate glomerular filtration rate），titratible acid，ammonium ion，urinary bicarbonate，net acid excretion were calculated.Results The Ccr of the alkalosis group and control group was（76.2±37.1）mL/min vs（98.5±31.9）mL/min，respectively（P=0.042） with a decrement of 22% in the alkalosis group.The titratible acid was（25.2±19.4）mmol/24 h vs（49.9±26.4）mmol/24 h，respectively（P=0.002）；the net acid excretion was（156.5±84.3） mmol/24 h vs（117.5±32.1）mmol/24 h，respectively（P=0.047）；the ammonium ion was（140.6±81.6） mmol/24 h vs（78.7±16.3）mmol/24 h，respectively（P=0.002）.The postoperative electrolytes of the alkalosis group and control group：[K+] was（3.51±0.67）mmol/L vs（4.14±0.59）mmol/L，respectively（P=0.002）；[Cl－] was（98.4±8.3）mmol/L vs（102.8±3.0）mmol/L，respectively（P=0.035）；[Ca2+] was（2.14±0.21）mmol/L vs（2.25±0.14）mmol/L，respectively（P=0.049）；[P] was（0.83±0.34）mmol/L vs（1.11±0.23）mmol/L，respectively（P=0.004）；[Na+] was（139.6±7.7）mmol/L vs（140.8±4.6）mmol/L，respectively（P=0.535）；[Mg2+] was（0.94±0.15）mmol/L vs（0.90±0.16）mmol/L，respectively（P=0.338）.Conclusions Decreased glomerular filtration rate and enhanced renal acidification function are the important factors that maintain the metabolic alkalosis during perioperative period.Potassium，chloride，calcium and phosphorus are decreased during metabolic alkalosis，while sodium and magnesium has no significant change.
Objective To compare the accuracy of different renal function measurements for predicting postoperativeadverse events after off-pump coronary artery bypass grafting （OPCAB） for Chinese patients. Methods Clinical data of 283 Chinese patients undergoing isolated OPCAB from January 2010 to December 2011 in the First Hospital of Peking University were retrospectively analyzed. There were 194 male and 89 female patients with their age of 65.0±9.7 years. Estimated glomerular filtration rate （eGFR） was calculated using Cockcroft-Gault equation，Modification of Diet in Renal Disease （MDRD） study equation and Chronic Kidney Disease Epidemiology Collaboration （CKD-EPI） equation respectively.Logistic multivariate regression analysis was performed to compare the accuracy of these 3 different renal function measure-ments for predicting postoperative adverse events. Results Logistic multivariate regression analysis showed that preoper-ative renal dysfunction was an independent risk factor for higher postoperative morbidity，more blood transfusion，prolongedhospitalization，mechanical ventilation time and length of ICU stay. Among the different postoperative complications，preop-erative renal dysfunction was an independent risk factor for postoperative acute renal injury，gastrointestinal bleeding，new onset atrial fibrillation and low cardiac output syndrome. Among Cockcroft-Gault equation，MDRD study equationand CKD-EPI equation to calculate eGFR，CKD-EPI equation was most accurate to predict postoperative morbidity （OR=1.227），acute renal injury （OR=1.534），new onset atrial fibrillation （OR=1.184），prolonged hospitalization（OR=1.160），mechanical ventilation time （OR=1.165） and ICU stay （OR=1.151）. Conclusion Preoperative renal dysfunction is an independent risk factor for postoperative adverse events after OPCAB. CKD-EPI equation is more suitable for predicting postoperative adverse events after OPCAB for Chinese patients.
Objective To investigate the relationship between glomerular filtration rate (GFR) and diabetic retinopathy (DR) and macular thickness in patients with type 2 diabetes mellitus (T2DM). Methods A total of 161 T2DM inpatients were enrolled in this study. There were 95 males (95 eyes) and 66 females (66 eyes), with an average age of (62.2±11.0) years. The average duration of diabetes was (14.8±7.9) years. The patients were grouped according to the degree of DR. Among them, 91 patients were no DR, 24 patients were mild non-proliferative DR (NPDR), 24 patients were moderate NPDR, 13 patients were severe NPDR and 9 eyes were proliferative DR (PDR). Severe NPDR and PDR were combine into severe DR group for statistical analysis. All patients underwent direct ophthalmoscope, fundus colorized photography, spectral domain optical coherence tomography (SD-OCT), fasting blood-glucose, glycated hemoglobin and renal function examinations. GFR was evaluated by99 mTcDTPA. DR degree was evaluated by direct ophthalmoscope and fundus colorized photography. Central subfield (CSF), central macular volume and mean retinal thickness (MRT) were measure by SD-OCT. The correlation between GFR and DR staging and macular retinal thickness were analyzed by Spearman correlation analysis and Pearson correlation analysis. Logistic regression analysis was used to analyze the correlation between GFR and presence of DR. Results GFR was gradually decreased in patients with no DR, mild NPDR, moderate NPDR and severe DR (F=12.32,P＜0.001). Pearson correlation analysis demonstrated that GFR was negatively correlated to CSF (r=−0.202,P=0.010); but no correlation with MRT (r=−0.087,P=0.272). Spearman correlation analysis demonstrated that GFR was negatively correlated to DR staging (r=−0.325,P＜0.001). The difference of DR prevalence rate in normal, slight abnormal renal function and renal insufficiency patients was significant (χ2=12.32,P=0.002). Logistic regression analysis demonstrated that lower levels of GFR was significantly associated with presence of DR (95% confidence interval=1.71–4.32, odds ratio=2.72,P＜0.001). Conclusion In T2DM patients, GFR is negatively correlated to DR staging and CSF. Lower GFR is independent risk factors for DR.