Effect of extending the platelet storage time on platelet utilization: predictions from a mathematical model of prophylactic platelet support

Bacterial culturing (BCU) or photochemical treatment (PCT) of platelet (PLT) concentrates may permit extending the storage time to 7 days at the cost of decreased viability of transfused PLTs. This study was aimed at predicting the impact this may have on the routine management of patients on prophylactic PLT support. The method included a mathematical model that represents the dynamics of prophylactic PLT support with standard, BCU or PCT PLTs. Data on posttransfusion PLT kinetics and the effect of PCT or storage time on PLT recovery and survival were obtained from published studies. Variables that influenced the level of PLT usage were the proportion of transfusions supplied with PLT on the last day of shelf-life, the use of PCT and the assumed degree of synergy between clinical factors of PLT consumption and either PCT or storage time. In the reference-case scenario, extending the PLT shelf-life to 7 days by BCU or PCT increased by 9 and 19%, respectively, the number of PLT transfusions per patient-year. In the worst-case scenario, these figures rose to 27 and 38%, respectively. Despite more intensive PLT usage, in most scenarios, the time that patients spent at PLT counts <10 x 10(9) L(-1) increased. Extending the shelf-life of PLT products will increase PLT usage. Such increase may be disproportionately larger for patients with complex conditions if there is a synergic interaction between storage time or PCT and clinical factors of PLT consumption, an issue that is worth further clinical research.     

781份尿液标本细菌培养结果分析及病原菌的耐药性检测

对我院 1999年 1月～ 2 0 0 1年 10月 781份临床诊断为泌尿系感染病人的尿液标本进行了细菌培养及药敏试验 ,其中阳性标本 (细菌计数高于 10 4～ 5CFU/ml) 2 80份 ,阳性率分别为 1999年的 2 5 %、2 0 0 0年的 38%、2 0 0 1年的 4 3% ,呈逐年上升趋势。检出率最高的需氧菌是大肠埃希氏菌、金黄色葡萄球菌 ,其次为表皮葡萄球菌、白色念珠菌、肠球菌等。药敏结果提示 :对各种抗生素的耐药性呈逐年上升 ,其中产ESBLS(超广谱 β 内酰胺酶 )的肠杆菌亦逐年上升 ,应引起临床极大关注。     

A model to predict the improvement of automated blood culture bacterial detection by doubling platelet sample volume

BACKGROUND: Some transmissions of bacterial infection from platelet (PLT) transfusion have occurred since introduction of automated blood culturing of apheresis PLTs. The majority of these cases involved false-negative culture results in which slow-growing Staphylococcus organisms were implicated. This study analyses the projected benefit in detecting slow growing organisms by increasing sample volume from 4 to 8 mL. STUDY DESIGN AND METHODS: Bacterial growth was modeled by varying the initial inoculum, doubling time, and lag time. The numbers of organisms present at a 24-hour sampling time were calculated. Poisson analysis was used to determine the fraction of 4- or 8-mL samples that could be detected because they contained organisms. For each inoculum, the percentage of improved detection by doubling sample volume was defined as delta, the difference between the percentage of detection of 8- and 4-mL samples. RESULTS: The maximum improvement in detection by doubling sample volume was 25 percent and did not depend on bacterial growth rate or lag time. As inocula increased toward 40 colony-forming units per unit, delta decreased. As lag and doubling times increased, inocula corresponding to maximum delta increased and the width of the distribution curve broadened. CONCLUSION: Doubling sample volume will not double the chance of detecting slow growing organisms, but instead is predicted to improve detection by 25 percent or less.     

Reactions to platelet transfusion: the effect of the storage time of the concentrate

Random platelet concentrates were pooled and depleted of leucocytes by centrifugation immediately prior to transfusion. The incidence and severity of reactions to 570 leucocyte-poor platelet transfusions in 74 patients were studied. An overall transfusion reaction rate of 13.7% was observed. The reaction rate to platelets stored for less than 3 days (8.7%) was significantly different from the reaction rate to platelets stored for 3 days or more (17.6%). Minor reactions as well as moderate and severe reactions were more frequent in the latter group. As most of the white blood cells were removed prior to transfusion, it is suggested that the reactions result from the transfusion of pyrogenic and/or vasoactive substances accumulated in the plasma of the concentrate during storage.     

Delayed insertion of blood culture bottles into automated continuously monitoring blood culture systems increases the time from blood sample collection to the detection of microorganisms in bacteremic patients

This study examined the effects on patients with bacteremia of delaying the insertion of a blood culture bottle into an automated, continuously monitoring blood culture system. We investigated the time taken from the collection of blood samples (collection) to the insertion of blood culture bottles inoculated with blood samples into the instrument (insertion), and compared the mean detection time from collection to a positive signal from the instrument with the time between collection and insertion. The study was conducted from January 2003 to December 2004 at Kyoto University Hospital. Insertion into the system on the day of blood sample collection was defined as same-day insertion, and insertion on a different day to collection was defined as delayed insertion. The 7394 aerobic and anaerobic blood culture bottle sets obtained during the study period included 4361 sets with same-day insertion and 3033 sets with delayed insertion. For same-day insertion, 458 microorganisms were isolated from 432 positive sets in which at least one blood culture bottle was positive. For delayed insertion, 405 microorganisms were isolated from 379 positive sets in which at least one blood culture bottle was positive. The mean detection time for all microorganisms was significantly earlier for same-day insertion than for delayed insertion (28.3 h vs. 45.0 h, respectively, P < 0.0001). Delays from collection to insertion affect the time from collection to the detection of microorganisms.     

The impact of workplace culture on the accountability of mental health nurses to involve consumers in care planning: A focused ethnography

Recovery‐oriented mental health practice guidelines recommend regular consumer involvement in care plans, yet in many acute settings, these are not routinely created thereby compromising accountability. This study explored the impact of workplace culture on the capacity of mental health nurses to involve consumers in care planning and consequently to work accountably. A focused ethnography was undertaken in one Australian inpatient unit involving mental health nurses and other health professionals. Data were derived from in‐depth semistructured interviews with 12 nurses and 6 months of nonparticipant observation of multidisciplinary meetings and clinical handovers. Workplace culture had an impact on mental health nurses' accountability practices. A culture that prioritized reduction in length of stay resulted in less recovery‐oriented care. Health professionals who paid more attention to crisis and risk management resulted in fewer opportunities for consumer‐involved care planning.     

Taking leave from work: the impact of culture on Japanese female nurses

Aims and objectives. This paper provides an overview of nurses’ working conditions in Japan, exploring tensions between nurses’ rights to take leave from work to fulfil family and personal needs and their actual ability to take such leave. It also considers possible effects of being restricted from taking such leave. Background. Little has been written on the specific needs of nurses who are mothers in the Japanese work environment. Research has focussed on the effects of heavy, stressful workloads and long working hours leading to burnout, death from overwork and suicides in Japanese culture. However, research that considers unique cultural and female issues in Japan affecting nursing work has not been published. Method. Discursive. Conclusion. The paper shows that there are many overlapping, complex issues affecting nurses working in Japan and their needs need to be considered and addressed in order to promote a healthier work environment, as well as a more humanistic environment. Relevance to clinical practice. Workplace issues are relevant to recruitment and retention and better conditions are likely to improve hospital functioning.     

The effect of heparin versus citrate on blood echogenicity in vitro: the role of platelet and platelet-neutrophil aggregates.

There is no consensus among investigators regarding which anticoagulant to use when studying the causes of in vitro blood echogenicity, despite the fact that heparin and calcium-chelating anticoagulants may have disparate effects due to their differing effects on platelets. This study quantitated the echogenicity of heparinized blood compared to citrated blood and found that it was greater in heparinized blood than in citrated blood when paired samples from the same donor, drawn at the same time were compared. By microscopic examination of the blood, this difference appeared to be due to the formation of platelet and platelet-neutrophil aggregates in the heparinized blood. This hypothesis was tested by comparing the echogenicity of heparinized blood to that of heparinized blood following platelet and white cell depletion. The results showed that taking away platelets and white cells virtually eliminated the echogenicity of heparinized blood; the impact of this result is discussed in the context of in vivo spontaneous contrast.     

儿童细菌性痢疾病原菌与药敏的动态分析及临床意义

目的了解新乡市区儿童菌痢病原菌分布特征及药敏变化特点，为临床更严谨更规范使用抗生素提供支持与依据。方法对同一地区不同时间段儿童菌痢病原菌及其药物敏感率进行对比分析。结果新乡市区儿童菌痢病原菌亚型分布中D群已呈明显上升趋势（x^2=11．288，P=0．001），但总体仍以B群感染为主（86％）；痢疾杆菌对常用抗生素敏感率由高到低次为头孢噻肟、丁胺卡那霉素、庆大霉素、头孢哌酮、头孢三嗪、头孢他啶、头孢唑啉、环丙沙星、氯霉素、复方新诺明及氨苄青霉素；对丁胺卡那霉素等六种抗生素的敏感率无明显变化（x^2=6．974，P=0．223）；痢疾杆菌单株多重耐药率高达40％以上，且两组间差异无统计学意义（x^2=0．037，P：0．847）。结论新乡市区儿童菌痢病原菌亚型分布正在发生改变；痢疾杆菌的耐药问题依然严重；对儿童菌痢选用抗生素应结合药敏，首选头孢噻肟等第三代头孢类抗生素或头孢唑啉，年长儿也可首选以丁胺卡那霉素为代表的氨基甙类，而喹诺酮类药物常常不做为儿童尤其7岁以下小儿菌痢的备选药物，氯霉素、复方新诺明及氨苄青霉素不再作为小儿菌痢的抗菌选择。     

Safety in psychiatric inpatient care: The impact of risk management culture on mental health nursing practice

The discourse of safety has informed the care of individuals with mental illness through institutionalization and into modern psychiatric nursing practices. Confinement arose from safety: out of both societal stigma and fear for public safety, as well as benevolently paternalistic aims to protect individuals from self‐harm. In this paper, we argue that within current psychiatric inpatient environments, safety is maintained as the predominant value, and risk management is the cornerstone of nursing care. Practices that accord with this value are legitimized and perpetuated through the safety discourse, despite evidence refuting their efficacy, and patient perspectives demonstrating harm. To illustrate this growing concern in mental health nursing care, we provide four exemplars of risk management strategies utilized in psychiatric inpatient settings: close observations, seclusion, door locking and defensive nursing practice. The use of these strategies demonstrates the necessity to shift perspectives on safety and risk in nursing care. We suggest that to re‐centre meaningful support and treatment of clients, nurses should provide individualized, flexible care that incorporates safety measures while also fundamentally re‐evaluating the risk management culture that gives rise to and legitimizes harmful practices.