Jinn-Yang Chen

Acute kidney injury network classification predicts in-hospital and long-term mortality in patients undergoing elective coronary artery bypass grafting surgery

OBJECTIVE Acute kidney injury (AKI) is a highly prevalent complication after cardiac surgery. It is associated with substantial morbidity and mortality. However, the definition of AKI has not been well established until the Acute Kidney Injury Network group outlined an easily used consentaneous staging system. The study aims to evaluate the association between this determination and in-hospital as well as long-term mortality in patients receiving elective coronary artery bypass grafting (CABG) surgery. METHODS Patients undergoing elective CABG surgery from January 2003 to December 2007 in a tertiary medical center were studied. The Acute Kidney Injury Network classification was applied for the diagnosis of perioperative AKI. Medical history and intra-operative variables were collected retrospectively. Multivariate analysis was used to identify the independent risk factors of in-hospital and long-term mortality. Long-term survival rates were calculated using the Kaplan-Meier method. RESULTS This study included 964 patients. The incidence of AKI following elective CABG was 19.8%. Only 7% of the study population developed AKI requiring renal replacement therapy after surgery. The overall in-hospital mortality rate was 5.1%. Significant independent risk factors for in-hospital mortality include increasing age, higher serum uric acid, postoperative requirement of intra-aortic balloon pumping (IABP) and extracorporeal membrane oxygenation (ECMO), perioperative AKI, and chronic dialysis (all p<0.05). Significant independent risk factors for long-term mortality include increasing age, lower serum albumin, higher serum uric acid, postoperative requirement of IABP and ECMO, perioperative AKI, and chronic dialysis (all p < 0.005). CONCLUSIONS Acute Kidney Injury Network classification is a powerful tool to evaluate the prognostic impact of AKI on both in-hospital and long-term mortality among patients undergoing elective CABG surgery.

Mycobacterium tuberculosis infection of end-stage renal disease patients in Taiwan: a nationwide longitudinal study

End-stage renal disease (ESRD) patients are vulnerable to Mycobacterium tuberculosis (MTB) infection, but the magnitude of the risk is uncertain. In addition, there is no reliable information on the MTB infection rate of patients undergoing different types of renal replacement therapy (RRT). We used the Taiwan National Health Insurance Research Database to conduct a 9-year nationwide longitudinal study. Among 49 983 ESRD patients who received three renal replacement modalities, there were 562 cases of MTB infection, corresponding to an incidence rate of 3.0 per 1000 patient-years. The risk of MTB infection relative to the general population was 4.5. Multivariate Cox regression analysis indicated that the independent risk factors for MTB infection in ESRD patients are old age (hazard ratio (HR) 1.17 per 10 years, p <0.001), male gender (HR 1.37, p <0.001), silicosis (HR 5.82, p <0.001), and chronic obstructive pulmonary disease (HR 1.68, p 0.012). Hyperlipidaemia (HR 0.71, p <0.001) and hypertension (HR 0.81, p 0.05) are associated with a lower infection rate. There was no effect of RRT modality on MTB infection rate.

The effect of weather on peritoneal dialysis (PD) prescription: seasonal variation in PD dialysate utilization.

♦ Background: There have been no reports on peritoneal dialysis (PD) solution utilization since this treatment was developed in the 1920s. The aim of the present investigation was to investigate if weather affects PD prescription. ♦ Study Design and Methods: This 10-year observational study used the Taiwan National Health Insurance Research Database. Setting and Participants: Claims for different concentrate PD dialysate were analyzed monthly. 2.5% and 4.25% PD solutes were defined as hypertonic solutions. Predictor: Monthly outdoor mean temperature. Outcome and Measurement: The relationship between monthly mean of PD dialysate utilization and monthly outdoor temperature was analyzed by linear regression. Monthly mean PD dialysate utilization amount in 4 quarters was analyzed by ANOVA. ♦ Results: During the 10-year study period, a clear seasonal variation in PD dialysate was observed. This seasonal variation was present regardless of age, gender, and the presence of hypertension, diabetes, and dyslipidemia. Monthly mean temperature was positively correlated to 1.5% dialysate utilization amount (r = 0.559, p < 0.001) and negatively correlated to 2.5% (r = –0.533, p < 0.001) and 4.25% (r = –0.410, p < 0.001) dialysate utilization amount. In longitudinal follow-up, hypertonic PD fluid utilization was higher in diabetic patients than in nondiabetic patients from the beginning of treatment. Thereafter, it increased rapidly and reached a plateau within 1 year. Limitations: Analysis of ultrafiltration amount, blood pressure, and body weight was unfeasible due to the nature of the database. ♦ Conclusion: The utilization of differential strengths of PD solutions has a seasonal cyclic pattern, with more hypertonic PD solution utilized in winter and more hypotonic PD solution in summer.

First Identification of Gordonia sputi in a Continuous Ambulatory Peritoneal Dialysis Patient with Peritonitis

Editor: When patients with continuous ambulatory peritoneal dialysis (CAPD)–associated peritonitis do not respond promptly to adequate antibiotic therapy, unusual organisms should be considered. Further identification should be undertaken in patients with relapsing peritonitis. Here, we present the first case report of CAPD peritonitis attributable to Gordonia sputi identified by genomic sequencing. A 69-year-old man with end-stage renal disease secondary to diabetic nephropathy had been on CAPD therapy since June 2008. He was admitted to hospital in August 2011 because of a first episode of peritonitis. Culture of the peritoneal effluent yielded gram-positive coryneform bacilli. The peritonitis was treated with intraperitoneal antibiotics (cefazolin and gentamicin) for 14 days. One month later, peritonitis recurred. Culture of peritoneal effluent again yielded gram-positive coryneform bacteria, which were also sensitive to cefazolin and gentamicin. The bacteria showed no extensive branching and presented dry, raised, salmon-to-orange colonies without aerial hyphae; hence, to accurately identify the organism, two universal primers, 5F (5′-TGA AGA GTT TGA TCA TGG CTC AG-3′) and 809r (5′-CGT GGA CTA CCA GGG TAT CTA A-3′), were used for the amplification to determine a partial 16S rrnA gene sequence (1). The sequence obtained matched with G. sputi. Because of the relapsing peritonitis, computed tomography imaging of the entire abdomen was arranged; it showed mild thickening of the parietal peritoneum, mesenteric haziness, and increased stranding of peritoneal fat. After intraperitoneal cefazolin and gentamicin for 2 weeks, the dialysate white blood cell count declined to 2/mm3. However, a third episode of peritonitis occurred 1 month later. Culture of the peritoneal effluent was also positive for G. sputi. The broth microdilution method showed that the organism was sensitive to cefazolin and gentamicin, as before. Despite 4 days of intraperitoneal cefazolin and gentamicin, the patient had persistent abdominal pain. repeat computed tomography imaging showed progressive mesenteric haziness. Diagnostic laparoscopy was therefore proposed. Laparoscopic findings included extensive filmy adhesions of the bowel and an accumulation of dirty ascites, but without abscess formation. The ascites and peritoneal dialysis catheter were removed, and the patient was switched to hemodialysis. After a change in antibiotics to intravenous vancomycin and ceftazidime, the patient was discharged under oral ciprofloxacin treatment. In the following 2 months, no relapse of peritonitis occurred. Members of the genus Gordonia belong to the suborder Corynebacterineae within the order Actinomycetales. The slow growth and difficult phenotype identification of Gordonia species means that isolates are usually incorrectly reported as rhodococcus (2), Corynebacterium (3), or nocardia (4) species. Such problems may have contributed to the organism initially being reported as coryneform during the first hospitalization in the current case, but then further identified as G. sputi by genomic sequencing at the second hospitalization for relapsing peritonitis. Because genomic sequencing is a common and inexpensive laboratory technique, and because the precise identification of Gordonia species requires genomic sequencing (5), we suggest that, for early diagnosis, genomic sequencing for Gordonia species should be used when CAPD patients present with gram-positive coryneform bacilli–related peritonitis. Because of the delayed diagnosis in this first reported case, the CAPD catheter had to be removed. Whether the present case suggests that future cases of G. sputi peritonitis would require CAPD catheter removal or a longer duration of antibiotics to prevent relapsing peritonitis may merit further investigation.

Crystallization in transfer set before continuous ambulatory peritoneal dialysis initiation-three case reports.

Editor: In our new continuous ambulatory peritoneal dialysis (CAPD) patients, the transfer set is applied after the Tenckhoff catheter is implanted. To assure good inflow and outflow, the surgeon uses 1.5% dialysate in the operating theater to flush the catheter through the attached transfer set. The transfer set is then filled with 1.5% dialysate (1.36% anhydrous glucose) and closed until the surgical wound has healed and training in the CAPD procedure is accomplished. Before CAPD initiation, the drainage system (Tenckhoff catheter and transfer set) is not routinely flushed, but is immobilized to the abdominal skin using the pouch of an abdominal binder (Figure 1) during the training period. Although peritoneal catheter malfunction has been described in previous reports, malfunction of the transfer set before CAPD initiation has seldom been described (1). Here, we present 3 cases in which patients found yellowish-brown crystals in their transfer set before CAPD initiation. Part of the set seemed occluded, although that observation was not tested by flushing the transfer set. The patients involved were 53, 71, and 59 years of age. All were women, and all were using a CAPD treatment system from Fresenius Medical Care. Their causes of end-stage renal disease were herb nephropathy, diabetic nephropathy, and analgesic nephropathy. In these patients, the Tenckhoff catheter has been implanted without any complications in 30 April 2008, 6 December 2010, and 26 October 2012. However, before CAPD could be initiated, the transfer sets were found to contain some yellowish-brown crystallike material (Table 1, Figure 2). After the transfer CoRReSPonDenCe