Diagnostic value of two reagent strips (Multistix 8 SG and Combur 2 LN) in cirrhotic patients with spontaneous bacterial peritonitis and symptomatic bacterascites

OBJECTIVE: Spontaneous bacterial peritonitis is a life-threatening complication in patients with liver cirrhosis requiring a rapid diagnosis. We have tested two reagent strips, Multistix 8 SG and Combur 2 LN for bedside diagnosis of spontaneous bacterial peritonitis and symptomatic bacterascites, a variant of spontaneous bacterial peritonitis. METHODS: Responses of the two strips in colorimetric scale were compared with results given by cyto-bacteriological analysis of ascitic fluid. Results with positivity in grades 1 and 2 of colorimetric scale were analyzed. RESULTS: Four hundred and forty three paracentesis were performed in 116 patients including 46 samples of ascitic fluid with spontaneous bacterial peritonitis occurring in 25 patients and 20 samples of ascitic fluid with symptomatic bacterascites occurring in 17 patients. Forty two percent of spontaneous bacterial peritonitis were culture-negative neutrocytic ascites, gram-positive pathogens and enterobacteriaceae were responsible for 36% and 21% episodes of spontaneous bacterial peritonitis and 71% and 29% episodes of symptomatic bacterascites respectively. Fifty seven percent of spontaneous bacterial peritonitis had polymorphonuclear cell count<1000/mm3. For spontaneous bacterial peritonitis diagnosis, grade 1 positive Multistix and Combur tests had a sensitivity of 69.6% and 80.4% respectively, and a negative predictive value of 96% and 97.3%. Grade 2 positivity increased specificity to 98% and 99.2% and positive predictive value to 75% and 91% for the two strips respectively. Grade 1 positive tests had a sensitivity of 100% and 90% and a negative predictive value of 100% and 99.4% respectively for diagnosis of spontaneous bacterial peritonitis with polymorphonuclear count > 1000/mm3. For symptomatic bacterascites diagnosis, grade 1 positive tests had a sensitivity of 22.4% and 44.4% respectively and a negative predictive value of 96% and 97%. CONCLUSION: Although Combur had a higher sensitivity than Multistix for the diagnosis of spontaneous bacterial peritonitis, sensitivity of the two strips remains low with polymorphonuclear cell count<1000/mm3. Grade 2 positive Combur test had an acceptable positive predictive value. Sensitivity of both strips is insufficient for diagnosis of symptomatic bacterascites. Rapid cyto-bacteriological analysis of ascitic fluid remains necessary for diagnosis of these complications.     

Clinical utility of blood cultures drawn from central vein catheters and peripheral venipuncture in critically ill medical patients

STUDY OBJECTIVE: To determine the sensitivity, specificity, and positive and negative predictive values of blood cultures obtained through a central vein catheter compared with peripheral venipuncture. DESIGN: Prospective cohort study. SETTING: A medical ICU (19 beds) from a university-affiliated urban teaching hospital. PATIENTS: Between February 2001 and October 2001, 300 paired blood culture specimens were obtained from 119 patients (2.52 paired cultures per patient). INTERVENTION: Prospective patient surveillance and data collection. Measurements and main results: Thirty-four paired culture results (11.3%; 95% confidence interval, 7.8 to 14.8%) were accepted as true-positives representing a true bacteremia. The sensitivity of catheter-drawn and peripheral venipuncture samples was 82.4% and 64.7%, respectively, and specificity was 92.5% and 95.9%. The positive predictive value was 58.3% for catheter-drawn samples and 66.7% for peripheral venipuncture samples, and the respective negative predictive values were 97.6% and 95.5%. CONCLUSIONS: In critically ill medical patients, the negative predictive value of blood samples obtained by catheter draw or peripheral venipuncture for suspected bloodstream infection is good. However, the sensitivity of blood samples obtained by either catheter draw or peripheral venipuncture alone is not adequate to recommend the elimination of blood samples obtained from the other site. Clinicians should also be aware that additional blood samples may be necessary when interpreting positive blood culture results for common skin or central vein catheter contaminants.     

Spontaneous bacterial peritonitis: a comparative study of 2 methods of ascitic fluid culture

The sensitivity in the diagnosis of spontaneous bacterial peritonitis of ascitic fluid inoculation in blood culture bottles has been compared with the conventional method. We have analyzed 74 positive ascitic fluid cultures from 64 patients, the samples being processed by both techniques simultaneously. While all the ascitic fluid cultures performed by inoculation in blood culture bottles were positive, in only 42 from the 74 conventional cultures (56, 75%) bacterial growth was detected (p less than 0.001). Nineteen bacterascites were diagnosed by inoculation in blood culture bottles and 10 by the conventional method (p = NS). Gram stain was only positive in 3 spontaneous bacterial peritonitis (6%). We conclude that ascitic fluid inoculation in blood culture bottles improves significantly the sensitivity of the microbiological diagnosis of spontaneous bacterial peritonitis, without increasing the diagnosis of bacterascites.     

Comparison of sensitivity, specificity, positive predictive value, and negative predictive value of stress testing versus 64-multislice coronary computed tomography angiography in predicting obstructive coronary artery disease diagnosed by coronary angiography

Sixty-four-multislice coronary computed tomographic angiography (CTA) and coronary angiography were performed in 145 patients (mean age 67 +/- 10 years), and stress testing was performed in 47 of these patients to determine the sensitivity, specificity, positive predictive value, and negative predictive value of coronary CTA and of stress testing in diagnosing obstructive coronary artery disease (CAD) in patients with suspected CAD. In 145 patients, coronary CTA had 98% sensitivity, 74% specificity, 90% positive predictive value, and 94% negative predictive value in diagnosing obstructive CAD. In 47 patients, stress testing had 69% sensitivity, 36% specificity, 78% positive predictive value, and 27% negative predictive value for diagnosing obstructive CAD, whereas coronary CTA had 100% sensitivity, 73% specificity, 92% positive predictive value, and 100% negative predictive value for diagnosing obstructive CAD. In conclusion, coronary CTA has better sensitivity, specificity, positive predictive value, and negative predictive value than stress testing in diagnosing obstructive CAD.     

Effect of delay of blood cultures on positive detection by automated blood culture system

The effect of entry delayed blood culture bottles until the start of incubation for mechanical detection of organism were compared using 2 major blood culture systems; BACTEC 9240 system and BacT/ALERT 3D system. Total of 13 bacterial strains; 5 gram-positive cocci, 7 gram-negative bacilli and Candida parapsilosis which were isolated mainly from blood cultures were used as the test strains. BACTEC 92F, 93F and BacT/ALERT FA, FN bottles were used as the blood culture bottles. All the bottles inoculated with the test strains were incubated and evaluated immediately after standing at room temperature for 24, 42, 48, 54 or 72 hours, using the respective automated blood culture systems. All the bottles were subcultured. The effect of entry delay the blood culture bottles for the mechanical detection was observed in many gram-negative organisms in BACTEC 9240 system. The blood cultures were evaluated not to be positive in 4 of the 10 samples on delaying for 24 hours or in any of the samples on delaying for 42 hours in the BACTEC 92F bottles inoculated with Escherichia coli. In Serratia marcescens, the blood cultures were evaluated not to be positive in 5 of the 10 samples on delaying for 24 hours or in any of the samples on delaying for 42 hours in the BACTEC 92F bottles. In Klebsiella pneumoniae, the blood cultures were evaluated not to be positive in 9 of the 10 samples on delaying for 42 hours. In Enterococcus faecalis, Pseudomonas aeruginosa and Proteus mirabilis, the blood cultures were evaluated not to be positive in 5-6 of the 10 samples on delaying for 42 hours. On the other hand, the blood cultures were evaluated to be positive in most of the samples of Acinetobacter calcoaceticus (except 3 of the 10 samples which were evaluated not to be positive) on delaying for 42 hours in BacT/ALERT 3 D system. The samples except part of Streptococcus spp. were detected by subculture in both the bottles. These results indicate that the delayed time of blood culture bottles before inoculation with the test bacterial samples affects the positive detection of blood cultures markedly in the blood culture system. Therefore, the immediate incubation was considered to be necessary.     

Surveillance culture utility and safety using low-volume blind bronchoalveolar lavage in the diagnosis of ventilator-associated pneumonia

Background and objectives:   Surveillance cultures may improve the prediction of ventilator-associated pneumonia (VAP) and empirical antibiotic selection. This study examined the utility and patient safety of blind, non-protected, low-volume mini-bronchial lavage (BM-BAL) surveillance cultures in predicting VAP.
Methodology:   A prospective, cohort study was performed in a large general intensive care unit. BM-BALs were collected within 12 h of admission then thrice weekly. Each BM-BAL was screened by Gram staining for intracellular organisms and then quantitatively cultured. VAP was diagnosed using the Clinical Pulmonary Infection Score. The concordance for isolates from the BM-BAL was assessed against concurrently collected endotracheal aspirates (EA).
Results:   Four hundred and twelve patients requiring a minimum of 48 h of mechanical ventilation were enrolled. Fifty patients developed 58 episodes of VAP. Concordant pathogens were found in 85% of BM-BAL specimens collected 2 days prior to VAP onset. Their antibiograms were stable over the preceding 4 days. The isolation of pathogens with colony counts ≥10⁴ cfu/mL from BM-BAL performed 2 days prior to the clinical onset of VAP had a sensitivity of 84%, specificity of 50%, positive predictive value of 31% and a negative predictive value of 93% for predicting the development of VAP. BM-BAL WCC, quantification of bacterial growth and the percentage of intracellular organisms were not helpful in predicting VAP diagnosis.
Conclusions:   BM-BAL surveillance cultures are well tolerated and useful in predicting the pathogens and their antibiograms causing VAP. Diagnostic specimen collection at the time of VAP onset is still required as surveillance cultures may be negative even one day prior to VAP onset.     

Diagnostic Value of Procalcitonin for Bacterial Infection in Elderly Patients in the Emergency Department

OBJECTIVES: To evaluate the diagnostic performance of procalcitonin (PCT) in elderly patients with bacterial infection in the emergency department (ED). DESIGN: Prospective. SETTING: ED of a tertiary care hospital. PARTICIPANTS: Elderly patients with systemic inflammatory response syndrome (SIRS) enrolled from September 2004 through August 2005. MEASUREMENTS: A serum sample for the measurement of PCT, two sets of blood cultures, and other cultures of relevant specimens from infection sites were collected in the ED. Two independent experts blinded to the PCT results classified the patients into bacterial infection and nonbacterial infection groups. RESULTS: Of the 262 patients with SIRS enrolled, 204 were classified as having bacterial infection and 48 as having bacteremia. PCT levels were significantly higher in patients with bacteremia than in those without. The area under the receiver operating characteristic curve for identification of bacteremia according to PCT was 0.817 for the old‐old group (≥75), significantly higher than 0.639 for the young‐old group (65–74); P=.02). The diagnostic sensitivity, specificity, positive predictive value, and negative predictive value of PCT for bacteremia in patients aged 75 and older were 96.0%, 68.3%, 33.8%, and 98.8%, respectively, with a PCT cutoff value of 0.38 ng/mL. CONCLUSION: PCT is sensitive for diagnosing bacteremia in elderly patients with SIRS at ED admission but is helpful in excluding bacteremia only in those aged 75 and older. PCT is not an independent predictor of local infections in these patients.     

环介导恒温扩增芯片法在下呼吸道感染病原体检测中的临床应用

目的分析环介导恒温扩增芯片法(LAMP)在下呼吸道感染病原体检测中的应用价值。 方法选择2018年1月至2018年9月空军军医大学第二附属医院收治的1 092例疑似下呼吸道感染患者,分析支气管肺泡灌洗液病原体检测结果,以细菌培养结果为金标准,评价LAMP检测8种常见下呼吸道感染病原体的灵敏度、特异度、阳性预测值、阴性预测值、阳性似然比、阴性似然比。 结果LAMP检测8种病原体的灵敏度差异较大,检测金黄色葡萄球菌灵敏度最高(100%),检测大肠埃希菌灵敏度最低(40%),检测8种病原体的特异度均高于94%。LAMP检测8种病原体的阳性预测值低于65%,阴性预测值高于98%,阳性似然比高于13,阴性似然比各病原体间差异较大,金黄色葡萄球菌阴性似然比最低(0.00),大肠埃希菌阴性似然比最高(0.60)。 结论LAMP在下呼吸道感染病原体检测中有较高的准确性,利于下呼吸道感染的早期诊断和精准治疗,具有临床意义。     

Diagnostic Yield of the Lactate Stress Test in 160 Patients with Suspected Respiratory Chain Disorder

Aim of the present study was to investigate the diagnostic yield of the lactate-stress-test in unselected patients with suspected respiratory-chain disorder (RCD). Serum lactate was determined before, during and after a 15-minute, constant 30W workload on a bicycle in 48 controls and 160 patients with suspected RCD. 122 had definite RCD 38 neurological disorders other than RCD. The sensitivity, specificity, positive predictive value, negative predictive value and pre-test likelihood of the test was 69, 74, 89, 42 and 76 % respectively. In conclusion, the lactate-stress-test proved a powerful tool to assess impaired oxidative metabolism in RCDs.     

血液肿瘤并发败血症143株病原菌分布及耐药分析

目的探讨血液肿瘤患者并发败血症病原菌分布及对抗生素的敏感性。方法回顾分析2004-01/2006-12住院的血液肿瘤患者血培养标本中分离的病原菌。结果472份血培养标本检出致病菌143株,阳性率30.3%。革兰阴性菌95株（66.4%）,以大肠埃希菌、肺炎克雷伯菌、铜绿假单胞菌为主;革兰阳性菌40株（28.0%）,以表皮葡萄球菌、金黄色葡萄球菌为主;真菌8株（5.6%）。革兰阴性杆菌除对亚胺培南、美洛培南的耐药率较低外,对其他抗菌药耐药性较高,铜绿假单胞菌对美洛培南也有一定耐药性。3种主要革兰阴性菌大肠埃希菌、肺炎克雷伯菌、铜绿假单胞菌对氨苄西林均高度耐药。革兰阳性球菌对万古霉素、替考拉宁耐药率低,尚未检出耐万古霉素菌株,部分肠球菌和溶血葡萄球菌株对替考拉宁耐药。结论血液肿瘤患者并发败血症的病原菌中,以革兰阴性菌为主;抗生素的大量使用,使革兰阴性菌和阳性菌的耐药率都增高,应根据细菌培养及药敏实验在临床中合理使用抗生素。     

Detection of heterogeneous, intermediate-vancomycin-resistant Staphylococcus aureus (hVISA) using low-concentration vancomycin disks

Heterogeneous, intermediate-vancomycin-resistant Staphylococcus aureus (hVISA) represents a threat of an incurable infection since the first report in 1997. The method used to detect hVISA isolates is a population analysis profile (PAP); however, it is impractical for routine laboratory analysis. We therefore tested a simple, reliable and inexpensive method for the detection of hVISA. Eighteen isolates of hVISA and 22 of vancomycin-sensitive S. aureus (VSSA) were included. The organisms were tested by the disk diffusion method, using 15-microg vancomycin disks on four different media: Mueller-Hinton agar (MHA), MHA plus 2% NaCI (MHAS), Brain Heart Infusion agar (BHA), and BHA plus 2% NaCl (BHAS). In addition, two different inoculum sizes, bacterial suspensions adjusted to 0.5 and 2.0 McFarland, were tested. The inhibition zone was read independently by three medical technologists after incubation at 37 degrees C for 24 and 48 hours. The use of MHAS with an inoculum size of 2.0 McFarland and 48-hour incubation period yielded the highest sensitivity (94.4%), specificity (81.8%), positive predictive value (80.9%), and negative predictive value (94.7%). The disk diffusion test with 15-microg vancomycin disk is simple and may be used as a screening method for the detection of hVISA.     

尿胰蛋白酶原-2检测对急性胰腺炎的诊断价值

目的评价免疫层析法检测尿胰蛋白酶原-2在急性胰腺炎（acute pancreatitis,AP）中的应用价值。方法对134例急性腹痛病例进行尿胰蛋白酶原-2及血、尿淀粉酶的检测,并比较其敏感性、特异性、阴性预测值、阳性预测值及准确度。结果30例AP患者中28例尿胰蛋白酶原-2阳性,敏感性为93．3％,血清淀粉酶检测的敏感性为86．7％（26／30）,尿淀粉酶检测的敏感性为83．3％（25／30）;104例其他急腹症中,8例尿胰蛋白酶原-2阳性,特异性为92．3％。血清淀粉酶检测的特异性为87．5％（91／104）;尿淀粉酶检测的特异性为85．6％（89／104）。尿胰蛋白酶原-2检测敏感性、特异性、阴性预测值、阳性预测值及准确度均最高,但三者之间差异无显著性（P〉0．05）。结论尿胰蛋白酶原-2是急腹症患者筛选AP快速而简便的方法,具有较高的特异性和敏感性。     

Detection of Gastrointestinal Bleeding by Radionuclide Scintigraphy

Scanning with Technetium 99m labeled autologus red blood cells was performed in 59 patients with clinical suspicion of acute and/or intermittent, chronic gastrointestinal bleeding. In 36 patients (61%), a definite site of bleeding could be demonstrated. A strong correlation with other modalities such as upper and lower gastrointestinal endoscopy, contrast angiography, and surgical exploration was found. Overall sensitivity of the procedure was 91%; specificity 100% and accuracy 93.3%. It is suggested that radionuclide scintigraphy provides a completely noninvasive, simple, and sensitive procedure which may he routinely used for the detection and localization of gastrointestinal bleeding.     

A prospective study of BK-virus-associated haemorrhagic cystitis in paediatric patients undergoing allogeneic haematopoietic stem cell transplantation

We investigated the incidence, risk factors and outcome of haemorrhagic cystitis (HC) in paediatric patients undergoing HSCT and the predictive value of BK viruria and viraemia for developing HC. Over a period of 54 months, 74 patients were recruited. The cumulative incidence of HC was 22%. Among 15 patients prospectively monitored for BK viruria and viraemia, four patients developed HC of grade > or =II. This group, which had two consecutive BK positive samples, showed a sensitivity of 100%, a specificity of 82%, a positive predictive value of 67%, and negative predictive value of 100% for developing HC. Analysed by a receiver-operator characteristic curve (ROC), a urine BK load >9 x 10(6) genomic copies/ml had a sensitivity of 95% and specificity of 90%; while a blood BK load >1 x 10(3) genomic copies/ml had a sensitivity of 40% and a specificity of 93% for HC, respectively. In univariate analysis, BK positivity was the only factor significantly associated with HC. After a median follow-up of 1.8 years, patients with HC showed a lower overall survival, 40 vs 65%, P 0.01, and a lower event-free survival, 42 vs 62%, P 0.03, compared to patients without HC. We conclude that BK detection in urine and/or plasma is a specific predictor for developing HC.     

Detection of potential pathogen in pancreatic fluid aspiration with metagenomic next-generation sequencing in patients with suspected infected pancreatic necrosis

BackgroundTimely and accurate microbial diagnosis is important in managing patients with infected pancreatic necrosis (IPN).AimsTo evaluate the diagnostic performance of Metagenomic next-generation sequencing (mNGS) in patients with suspected IPN.MethodsThe clinical data of 40 patients with suspected IPN who underwent CT-guided pancreatic fluid aspiration were retrospectively analyzed. Microbial culture and mNGS were simultaneously applied to identify the potential pathogens. The diagnostic performance of the mNGS was assessed by sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV).ResultsThe mNGS report can be obtained significantly earlier than culture methods (42 (36–62 h) vs. 60 (42–124 h), P = 0.032). Across all the study samples, seven species of bacteria and two species of fungi were reported accordingly to the culture results, while 22 species of bacteria and two species of fungi were detected by mNGS. The sensitivity, specificity, NPV, and PPV of mNGS were 88.0%, 100%, 83.33%, and 100%, respectively.ConclusionsThe diagnostic accuracy of mNGS in patients with suspected IPN is satisfactory. Moreover, mNGS may broaden the range of identifiable infectious pathogens and provide a more timely diagnosis.     

Low yield of microbiologic studies on pleural fluid specimens

BACKGROUND: It is generally recommended that pleural fluid samples from pleural effusions of unknown cause be cultured for bacteria, mycobacteria, and fungi. However, the utility of this practice has been not been adequately assessed. DESIGN: Retrospective review. SETTING: Tertiary care, referral medical center. PATIENTS: Five hundred twenty-five patients undergoing diagnostic thoracentesis at Mayo Medical Center, Rochester, MN, over a 12-month period from July 1, 2001, to June 30, 2002. INTERVENTIONS: None. MEASUREMENTS AND RESULTS: Among 525 patients undergoing diagnostic thoracenteses, 476 patients (91%) had one or more cultures performed on their pleural fluid specimens. Thirty-nine positive results (3.0% of 1,320 cultures) occurred in 35 of these 476 patients (7.4%). After excluding likely contaminants, true pathogens were identified in only 19 of 1,320 pleural fluid cultures (1.4%) belonging to 15 patients (3.2% of those who had cultures performed on their pleural fluid specimen). These positive results included 2.3% of aerobic bacterial, 1.2% of anaerobic bacterial, 1.4% of fungal, and 0% of mycobacterial cultures. Microbiologic smears performed on these pleural fluid samples included 357 Gram stains, 109 fungal smears (potassium hydroxide), and 232 acid-fast smears with positive yields of 2.5%, 0%, and 0%, respectively. These positive findings represented 1.3% of all smears performed. Of the specimens obtained from outpatient thoracenteses, only one had a true-positive result (0.8%). Only 1.1% (four specimens) of the cultures performed on free-flowing effusions demonstrated true pathogens; three of these four specimens grew fungi. CONCLUSIONS: The positive yield of microbiologic smears and cultures on pleural fluid specimens is low, particularly in the outpatient setting and in patients with free-flowing effusions. Microbiologic testing of pleural fluid specimens should be ordered more selectively.     

前降钙素在肾移植术后患者肺部细菌感染与病毒感染中的诊断价值

目的探讨前降钙素（PCT）在肾移植术后患者肺部细菌感染与病毒感染中的诊断价值。方法 64例肾移植术后肺部感染患者在完善相关检查后确定细菌和病毒感染共38例,同时采用免疫发光分析进行检测PCT水平。PCT水平以0.5ng/ml为阳性分界值。结果将各炎症指标绘制ROC曲线,显示PCT≥0.5ng/ml对鉴别细菌感染时较体温、白细胞计数、C反应蛋白（CRP）等炎症指标其敏感性和特异性更高,分别为73%和69%、52%/36%、50%/36%、54%/43%;PCT阳性患者细菌感染的发生率为73%,明显高于PCT阴性患者（P=0.000）,而PCT阴性患者病毒感染的发生率为69%,明显高于PCT阳性患者（P=0.006）,细菌感染与病毒感染PCT水平有显著差异（P〈0.01）。结论血清PCT水平可以作为肾移植术后肺部感染病原体的辅助诊断指标,其水平以0.5ng/ml作为阳性分界值对鉴别肺部细菌感染与病毒感染具有重要意义。     

Bronchoalveolar lavage or oropharyngeal cultures to identify lower respiratory pathogens in infants with cystic fibrosis

As collections of lower respiratory tract specimens from young children with cystic fibrosis (CF) are difficult, we determined whether oropharyngeal cultures predicted lower airway pathogens. During 1992–1994, 75 of 90 (83%) infants with CF diagnosed by neonatal screening had 150 simultaneous bronchoalveolar lavage (BAL) and oropharyngeal specimens collected for quantitative bacterial culture at a mean age of 17 months (range, 1–52). Ten children undergoing bronchoscopy for stridor served as controls. Total and differential cell counts and interleukin-8 concentrations were measured in BAL fluid. A subset of bacterial pathogens were typed by pulsed field gel electrophoresis. A non-linear relationship with inflammatory markers supported a diagnosis of lower airway infection when ≥10⁵ colony-forming units/ml were detected. This criterion was met in 47 (31%) BAL cultures from 37 (49%) children. Staphylococcus aureus (19%), Pseudomonas aeruginosa (11%), and Hemophilus influenzae (8%) were the major lower airway pathogens. In oropharyngeal cultures, S. aureus (47%), Escherichia coli (23%), H. influenzae (15%), and P. aeruginosa (13%) predominated. The sensitivity, specificity, and positive and negative predictive values of oropharyngeal cultures for pathogens causing lower respiratory infections were 82%, 83%, 41%, and 97%, respectively. When there was agreement between paired oropharyngeal and BAL cultures, genetic fingerprinting showed some strains of the same organism were unrelated. We conclude that oropharyngeal cultures do not reliably predict the presence of bacterial pathogens in the lower airways of young CF children. Pediatr Pulmonol. 1996; 21:267–275. © 1996 Wiley-Liss, Inc.     

Value and limits of the determination of aortic output by Doppler echocardiography in the quantification of aortic valve insufficiencies]

The aim of this study was to assess the value and limitations of Doppler echocardiographic measurement of aortic flow in the quantification of aortic regurgitation. Sixty-one patients were examined by Doppler echocardiography within 48 hours of cardiac catheterisation. There were 9 Grade I, 18 Grade II, 18 Grade III and 16 Grade IV angiographic aortic regurgitations. The mean aortic blood flow in angiographic Grades I and II (p less than 0.01). A correlation was observed between Doppler aortic flow and the angiographic grade of regurgitation (r = 0.66, p less than 0.001) and between aortic flow and regurgitant fraction (r = 0.68, p less than 0.001). Aortic flow greater than 10 l/mn identified angiographic Grades III or IV regurgitation with a sensitivity and specificity of 73.5% and 92.5% respectively and a positive and negative predictive values of 92.5% and 73.5% respectively. Aortic regurgitation with a regurgitant fraction greater than 40% was identified by a pulsed Doppler aortic blood flow greater than 10 l/mn with a sensitivity and specificity of 70% and 93% respectively, and positive and negative predictive values of 95% and 61% respectively. The sensitivity of this criterion is relatively poor as some severe aortic regurgitations have aortic flows of less than 10 l/mn: these patients have low outputs because of left ventricular dysfunction which is apparent from measurement of left ventricular fractional shortening.     

The relevance of cultures of catheter-drawn blood and heparin-lock fluid to diagnose infection in hematologic patients

Summary The results of bacteriologic cultures of blood and heparin-lock fluid, both drawn from the central venous catheters of 54 consecutive oncohematologic patients, have been used to determine their value for the diagnosis of systemic and catheter-associated infection. In 30 patients with clinical signs of infection (bacteremia or septicemia), 74 of 1000 (7.4%) heparin-lock fluid cultures, 114 of 542 (21%) catheter-drawn blood cultures, and 36 of 134 (26%) venipuncture blood cultures became positive, whereas in 24 patients without clinical signs of infection the respective values were 5 of 700 (0.7%), one of 220 (0.4%), and none of ten cultures. Comparison of the results of cultures sampled on the same day reveals that the positive and negative predictive values for catheter-drawn blood cultures, with the venipuncture blood cultures taken as the standard for bacteremia, are 82% and 95% respectively. The results of heparin-lock fluid are indicative for clinically relevant colonization of the catheter. Three or more positive heparin-lock fluid cultures, sampled on subsequent days, were correlated with the occurrence of bacteremia or septicemia with a positive predictive value of 100%. The conclusions are supported by the results of scanning electron microscopy.