Prognostic value of noninvasive measures of contractility in emergency department patients with severe sepsis and septic shock undergoing early goal-directed therapy

Purpose

Reversible ventricular dysfunction is common in sepsis. Impedance cardiography allows for noninvasive measurement of contractility through time interval or amplitude-based measures. This study evaluates the prognostic capacity of these measures in patients with severe sepsis or septic shock in the emergency department.

Methods

This is a prospective observational cohort study of 56 patients older than 18 years meeting criteria for early goal-directed therapy (lactate level >4 mmol/L or systolic blood pressure <90 mm Hg after 2-L isotonic sodium chloride solution). Continuous collections of contractility measures were performed, and patients were followed until discharge or in-hospital death.

Results

A significant 57% reduction in the accelerated contractility index (ACI) in nonsurvivors (71 1/s² [41-102]) compared with survivors (123 1/s² [98-147]) existed. Only ACI predicted in-hospital mortality (area under the receiver operating characteristic curve = 0.70, P < .01). Accelerated contractility index did not correlate with amount of prior fluid administration, central venous pressure, number of cardiac risk factors, or troponin I value. An ACI of less than 40 1/s² is 95% (84-99) specific with a positive likelihood ratio of 8.8 for predicting in-hospital mortality.

Conclusions

A reduced ACI is associated with mortality in critically ill emergency department patients presenting with severe sepsis and septic shock meeting criteria for early goal-directed therapy. This association appears to be independent of clinical or laboratory predictors of cardiac dysfunction or preload.     

严重脓毒血症和脓毒性休克早期目标化治疗在中国大陆部分医院急诊科实施现状调查

目的 了解早期目标化治疗(early goal-directed therapy,EGDT)在中国内地医院急诊科实施情况,分析存在的问题.方法 采取问卷方式,调查26个省市、56家医院急诊科的516名医生对EGDT的知晓率、实施率及不能实施的原因.结果 三甲医院的医生88.7%知道严重脓毒血症和脓毒性休克的诊断标准、91.6%知道有相关指南和74.2%知道早期目标化治疗的具体内容;而二甲医院的医生则分别只有30.2%、34.1%和25.6%;三乙医院分别为68.3%,77.3%和43.9%.不同级别医生知晓率差异有统计学意义(P＜0.05).三甲医院EGDT完全实施率13.3%,二甲医院没有能完全实施,其急诊医生认为,EGDT不能完全实施最主要的原因是患者经济条件(60.9%),其次是医生个人认知水平及临床操作技能(53.1%).但即使是在完全了解EGDT的具体内容和主导思想以后,也仅有31.0%的医生愿意在实际工作中去完全实施,有7.0%仍坚持完全不实施.结论 中国急诊医生中对EGDT知晓率及实施意愿都较低,是影响其实施的重要原因;其他影响因素还包括:患者经济条件和依从性差、缺乏推广实施的制度与相关专业团队的建设、医生不愿承担过多的医疗风险以及对EGDT有效性的认可度低.     

Commentary: Cabanna M et al. (1999). Why don’t physicians follow clinical practice guidelines? A framework for improvement

Despite wide promulgation, clinical practice guidelines have had limited effect on changing physician behaviour. Little is known about the process and factors involved in changing physician practices in response to guidelines. The aim is to review barriers to physician adherence to clinical practice guidelines. We searched the MEDLINE, Educational Resources Information Center and Health STAR databases (January 1966 to January 1998), bibliographies; textbooks on health behaviour or public health and references supplied by experts to find English language article titles that describe barriers to guideline adherence. Of 5658 articles initially identified, we selected 76 published studies describing at least one barrier to adherence to clinical practice guidelines, practice parameters, clinical policies or national consensus statements. One investigator screened titles to identify candidate articles, then two investigators independently reviewed the texts to exclude articles that did not match the criteria. Differences were resolved by consensus with a third investigator. Two investigators organized barriers to adherence into a framework according to their effect on physician knowledge, attitudes or behaviour. This organization was validated by three additional investigators. The 76 articles included 120 different surveys investigating 293 potential barriers to physician guideline adherence, including awareness (n = 46), familiarity (n = 31), agreement (n = 33), self‐efficacy (n = 19), outcome expectancy (n = 8), ability to overcome the inertia of previous practice (n = 14), and absence of external barriers to perform recommendations (n = 34). The majority of surveys [70 (58%) of 120] examined only one type of barrier. Studies on improving physician guideline adherence may not be generalizable because barriers in one setting may not be present in another. Our review offers a differential diagnosis for why physicians do not follow practice guidelines, as well as a rational approach towards improving guideline adherence and a framework for future research. Abstract reprinted from the Journal of the American Medical Association volume 282, Cabanna M et al., ‘Why don’t physicians follow clinical practice guidelines? A framework for improvement.’, pages 1458–1465. © 1999, reproduced with permission from the American Medical Association.     

Commentary: Hugonnet S et al. (2007). The effect of workload on infection risk in critically ill patients

Objective: There is growing evidence that low nurse staffing jeopardizes quality of patient care. The objective of the study was to determine whether low staffing level increases the infection risk in critical care. Design: Observational, single‐centre, prospective cohort study. Setting: Medical intensive care unit of the University of Geneva Hospitals, Switzerland. Patients: All patients admitted over a 4‐year period. Interventions: None. Measurements and main results: Study variables included all infections acquired in critical care, daily nurse‐to‐patient ratio, demographic characteristics, admission diagnosis and severity score, comorbidities, daily individual exposure to invasive devices and selected drugs. Of a cohort of 1883 patients totalling 10 637 patient‐days, 415 (22%) developed at least one health care‐associated infection (HCAI) while in critical care. Overall infection rate was 64·5 episodes per 1000 patient‐days. Infected patients experienced higher mortality with a longer duration of stay both in critical care and in the hospital than non‐infected patients (all p < 0·001). Median 24‐h nurse‐to‐patient ratio was 1·9. Controlling for exposure to central venous catheter, mechanical ventilation, urinary catheter and antibiotics, we found that higher staffing level was associated with a >30% infection risk reduction (incidence rate ratio, 0·69; 95% CI: 0·50–0·95). We estimated that 26·7% of all infections could be avoided if the nurse‐to‐patient ratio was maintained >2·2. Conclusions: Staffing is a key determinant of HCAI in critically ill patients. Assuming causality, a substantial proportion of all infections could be avoided if nurse staffing were to be maintained at a higher level. Abstract reprinted from Critical Care Medicine, volume 35, Hugonnet S et al., ‘The effect of workload on infection risk in critically ill patients.’, pages 76–81. © 2007, reproduced with permission from Lippincott Williams & Wilkins.     

Commentary: Hillman K, Chen J, et al. (2005). Introduction of the medical emergency team (MET) system: a cluster-randomised controlled trial

Patients with cardiac arrests or who die in general wards have often received delayed or inadequate care. We investigated whether the medical emergency team (MET) system could reduce the incidence of cardiac arrests, unplanned admissions to intensive care units (ICU) and deaths. We randomized 23 hospitals in Australia to continue functioning as usual (n= 11) or to introduce a MET system (n= 12). The primary outcome was the composite of cardiac arrest, unexpected death or unplanned ICU admission during the 6‐month study period after MET activation. Analysis was by intention to treat. Introduction of the MET increased the overall calling incidence for an emergency team (3·1 versus 8·7 per 1000 admissions, p= 0·0001). The MET was called to 30% of patients who fulfilled the calling criteria and who were subsequently admitted to the ICU. During the study, we recorded similar incidence of the composite primary outcome in the control and MET hospitals (5·86 versus 5·31 per 1000 admissions, p= 0·640), as well as of the individual secondary outcomes (cardiac arrests, 1·64 versus 1·31, p= 0·736; unplanned ICU admissions, 4·68 versus 4·19, p= 0·599; and unexpected deaths, 1·18 versus 1·06, p= 0·752). A reduction in the rate of cardiac arrests (p= 0·003) and unexpected deaths (p= 0·01) was seen from baseline to the study period for both groups combined. The MET system greatly increases emergency team calling but does not substantially affect the incidence of cardiac arrest, unplanned ICU admissions or unexpected death. Abstract reprinted from the The Lancet volume 365, Hillman K et al., ‘Introduction of the medical emergency team (MET) system…’, pages 2091–7. © 2005, with permission from Elsevier.     

Commentary: Nemoto T et al. (1999). Automatic control of pressure support mechanical ventilation using fuzzy logic

There is currently no universally accepted approach to weaning patients from mechanical ventilation, but there is clearly a feeling within the medical community that it may be possible to formulate the weaning process algorithmically in some manner. Fuzzy logic seems suited to this task because of the way it so naturally represents the subjective human notions employed in much of medical decision‐making. The purpose of the present study was to develop a fuzzy logic algorithm for controlling pressure support ventilation in patients in the intensive care unit, utilizing measurements of heart rate, tidal volume, breathing frequency and arterial oxygen saturation. In this report, we describe the fuzzy logic algorithm and demonstrate its use retrospectively in 13 patients with severe chronic obstructive pulmonary disease, by comparing the decisions made by the algorithm with what actually transpired. The fuzzy logic recommendation agreed with the status quo to within 2 cm H₂O an average of 76% of the time, and to within 4 cm H₂O an average of 88% of the time (although in most of these instances no medical decisions were taken as to whether or not to change the level of ventilatory support). We also compared the predictions of our algorithm with those cases in which changes in pressure support level were actually made by an attending physician, and found that the physicians tended to reduce the support level somewhat more aggressively than the algorithm did. We conclude that our fuzzy algorithm has the potential to control the level of pressure support ventilation from ongoing measurements of a patient’s vital signs. Abstract reprinted from the American Journal of Respiratory and Critical Care Medicine, volume 160, Nemoto T et al., ‘(1999) Automatic control of pressure support mechanical ventilation using fuzzy logic.’, pages 550–556. © 1999, reproduced with permission from The American Thoracic Society.     

Commentary: Numata Y, Schultzer M, et al. (2006). Nurse staffing levels and hospital mortality in critical care settings: literature review and meta-analysis

This paper reports a review of the literature on the association between critical care nurse staffing levels and patient mortality. Statistically significant inverse associations between levels of nurse staffing and hospital mortality have not been consistently found in the literature. Critical care settings are ideal to address this relationship due to high patient acuity and mortality, high intensity of the nursing care required and availability of individual risk adjustment methods. Major electronic databases were searched, including MEDLINE, EMBASE, and the Cumulative Index of Nursing and Allied Health Literature. The search terms included critical/intensive care, quality of health care, mortality/hospital mortality, personnel staffing and scheduling, and nursing staff (hospital). Only papers published in English were included. The original search was conducted in 2002 and updated in 2005. Nine studies were selected from 251 references screened. All nine were observational. Six were conducted in the USA, one in Austria, one in Brazil, and one in Scotland. The unadjusted risk ratio of nurse staffing (high versus low) on hospital mortality were combined meta-analytically (five studies). The pooled estimate was 0.65 (95% confidence interval 0.47-0.91). However, after adjusting for various covariates within each study, the individually reported associations between high nurse staffing and low hospital mortality became non-significant in all but one study. The impact of nurse staffing levels on patients' hospital mortality in critical care settings was not evident in the reviewed studies. Methodological challenges that might have impeded correct assessment of the association include measurement problems in exposure status and confounding factors, often uncontrolled. The lack of association also indicates that hospital mortality may not be sensitive enough to detect the consequences of low nurse staffing levels in critical care settings. Abstract reprinted from the Journal of Advanced Nursing volume 55, Numata Y et al., 'Nurse staffing levels and hospital mortality in critical care settings: literature review and meta-analysis.', pages 435-448. (c) 2006, with permission from Blackwell Publishing Ltd.     

One year mortality of patients treated with an emergency department based early goal directed therapy protocol for severe sepsis and septic shock: a before and after study

Introduction  

Early structured resuscitation of severe sepsis has been suggested to improve short term mortality; however, no previous study has examined the long-term effect of this therapy. We sought to determine one year outcomes associated with implementation of early goal directed therapy (EGDT) in the emergency department (ED) care of sepsis.     

Commentary: Ulger F et al. (2009). Are we aware how contaminated our mobile phones with nosocomial pathogens?

Background: The objective of this study was to determine the contamination rate of the health care workers’ (HCWs) mobile phones and hands in operating room and intensive care unit (ICU). Micro‐organisms from HCWs hands could be transferred to the surfaces of the mobile phones during their use. Methods: Two hundred HCWs were screened; samples from the hands of 200 participants and 200 mobile phones were cultured. Results: In total, 94·5% of phones demonstrated evidence of bacterial contamination with different types of bacteria. The Gram‐negative strains isolated from mobile phones were 31·3%, and the ceftazidime‐resistant strains from the hands were 39·5%. Staphylococcus aureus strains isolated from mobile phones of 52% and those strains isolated from hands of 37·7% were methicillin resistant. Distributions of the isolated micro‐organisms from mobile phones were similar to those from hands isolates. Some mobile phones were contaminated with nosocomial important pathogens. Conclusion: These results showed that HCWs hands and their mobile phones were contaminated with various types of micro‐organisms. Mobile phones used by HCWs in daily practice may be a source of nosocomial infections in hospitals. Abstract reprinted from Annals of Clinical Microbiology and Antimicrobials, volume 8, Ulger F et al., ‘Are we aware how contaminated our mobile phones with nosocomial pathogens?’, doi:10.1186/1476‐0711‐8‐7. © 2009, reproduced with permission from BioMed Central Ltd.     

Commentary: Bouza C et al. (2007). Unplanned extubation in orally intubated medical patients in the ICU: a prospective cohort study

Background: Unplanned endotracheal extubation (UE) is recognized as the most common airway adverse event in the intensive care unit (ICU). Objectives: We examined the incidence, circumstances, and outcome of UE in orally intubated medical patients in the ICU. Methods: We performed a 12‐month prospective cohort study in a tertiary‐care medical ICU. Results: A total of 344 consecutive adults who were orally intubated and mechanically ventilated for 3710 days were included. The overall incidence density of UE was 0·92 of 100 days of ventilation. Eight episodes (24%) occurred in patients receiving mechanical ventilation (MV) and not in the weaning process versus 26 episodes (76%) in patients scheduled for weaning. UE was reported as intentional in 71% of cases and as accidental in 29% of cases. In 59% of UE cases, patients were without caregivers at the bedside when the episode took place, and 46% of cases occurred during the night shift. Reintubation was required in 41% of patients and was strongly associated with the accidental nature of the episode [odds ratio (95% confidence interval): 4.3 (1.9–9.6)]. Compared with patients without UE, patients with UE had a lower mortality rate [odds ratio (95% confidence interval): 0·21 (0·6–0·8)] but longer days on MV (11.5 versus 5, P _ 0·09) and ICU stay (13.5 versus 6, P _ 0·08). Conclusions: This study does not confirm the highest rates of UE previously reported in orally intubated medical patients in the ICU or the association with mortality in this scenario. However, UE increased the need for MV and ICU care. We found a moderate to high prevalence of potentially modifiable risk factors for UE, suggesting unsatisfactory ICU practices. Abstract reprinted from Heart & Lung, volume 36, Bouza C et al., ‘Unplanned extubation in orally intubated medical patients in the ICU: a prospective cohort study.’, pages 270–276. ©2007, reproduced with permission from Elsevier Limited.