Year in review in Intensive Care Medicine 2009: I. Pneumonia and infections, sepsis, outcome, acute renal failure and acid base, nutrition and glycaemic control

The role of memories on health-related quality of life after intensive care unit care: an unforgettable controversy?

Background

Decreased health-related quality of life (HRQoL) is a significant problem after an intensive care stay and is affected by several known factors such as age, sex, and previous health-state. The objective of this study was to assess the association between memory and self-reported perceived HRQoL of patients discharged from the intensive care unit (ICU).

Methods

A prospective, multicenter study involving nine general ICUs in Portugal. All adult patients with a length of stay >48 hours were invited to participate in a 6-month follow-up after ICU discharge by answering a set of structured questionnaires, including EuroQol 5-Dimensions and ICU memory tool.

Results

A total of 313 (52% of the eligible) patients agreed to enter the study. The median age of patients was 60 years old, 58% were males, the median Simplified Acute Physiology Score II (SAPS II) was 38, and the median length of stay was 8 days for ICU and 21 days for total hospital stay. Eighty-nine percent (n=276) of the admissions were emergencies. Seventy-eight percent (n=234) of the patients had memories associated with the ICU stay. Patients with no memories had 2.1 higher chances (P=0.011) of being in the bottom half of the HRQoL score (<0.5 Euro-Qol 5-Dimensions index score). Even after adjusting for pre-admission characteristics, having memories was associated with higher perceived HRQoL (adjusted odds ratio =2.1, P=0.022).

Conclusion

This study suggests that most of the ICU survivors have memories of their ICU stay. For the ICU survivors, having memories of the ICU stay is associated with a higher perceived HRQoL 6 months after ICU discharge.

Gut Motility Issues in Critical Illness

Acute gastrointestinal injury (AGI) is common in critical illness and negatively affects outcome. A variety of definitions have been used to describe AGI, which has led to clinical confusion and hampered comparison of research studies across institutions. An international working group of the European Society of Intensive Care Medicine was convened to standardize definitions for AGI and provide current evidence-based understanding of its pathophysiology and management. This disorder is associated with a wide variety of signs and symptoms and may be difficult to detect, therefore a high index of suspicion is warranted.

A quick and low-cost PCR-based assay for Candida spp. identification in positive blood culture bottles

Background

Differences in the susceptibility of Candida species to antifungal drugs make identification to the species level important for clinical management of candidemia. Molecular tests are not yet standardized or available in most clinical laboratories, although such tests can reduce the time required for species identification, as compared to the conventional culture-based methods. To decrease laboratory costs and improve diagnostic accuracy, different molecular methods have been proposed, including DNA extraction protocols to produce pure DNA free of PCR inhibitors. The objective of this study was to validate a new format of molecular method, based on the internal transcribed spacer (ITS) of the rDNA gene amplification followed by sequencing, to identify common and cryptic Candida species causing candidemia by analyzing DNA in blood culture bottles positive for yeasts.

Methods

For DNA extraction, an “in-house” protocol based on organic solvent extraction was tested. Additional steps of liquid nitrogen incubation followed by mechanical disruption ensured complete cell lysis, and highly pure DNA. One hundred sixty blood culture bottles positive for yeasts were processed. PCR assays amplified the ITS region. The DNA fragments of 152 samples were sequenced and these sequences were identified using the GenBank database (NCBI). Molecular yeast identification was compared to results attained by conventional method.

Results

The organic solvent extraction protocol showed high reproducibility in regards to DNA quantity, as well as high PCR sensitivity (10 pg of C. albicans DNA and 95% amplification on PCR). The identification of species at the molecular level showed 97% concordance with the conventional culturing method. The molecular method tested in the present study also allowed identification of species not commonly implicated in human infections.

Conclusions

This study demonstrated that our molecular method presents significant advantages over the conventional yeast culture identification method by providing accurate results within 24 hours, in contrast to at least 72 hours required by the automated conventional culture method. Additionally, our molecular method allowed the identification of mixed infections, as well as infections due to emergent fungal pathogens. This economical DNA extraction method developed in our laboratory provided high-quality DNA and 60% cost savings compared to commercial methods.

Hospital mortality prognostication in sepsis using the new biomarkers suPAR and proADM in a single determination on ICU admission

PURPOSE

The soluble form of the urokinase-type plasminogen activator receptor (suPAR) and proadrenomedullin (proADM) are two new and promising sepsis biomarkers. We assessed the prognostic value of a single determination of proADM and suPAR, comparing them with C-reactive protein (CRP) and procalcitonin (PCT), and evaluating whether their addition to severity scores (APACHE II and SOFA) could improve their prognostic accuracy.

METHODS

A single-centre prospective observational study conducted in an adult intensive care department at Marques de Valdecilla University Hospital in Spain. APACHE II and SOFA scores, CRP, PCT, suPAR and proADM levels on the day of ICU admission were collected.

RESULTS

A total of 137 consecutive septic patients were studied. The best area under the curve (AUC) for the prediction of in-hospital mortality was for APACHE II (0.82) and SOFA (0.75) scores. The ROC curve for suPAR yielded an AUC of 0.67, higher than proADM (0.62), CRP (0.50) and PCT (0.44). Significant dose-response trends were found between hospital mortality and suPAR (OR Q4 = 4.83, 95% CI 1.60-14.62) and pro-ADM (OR Q4 = 3.00, 95% CI 1.06-8.46) quartiles. Non-significant associations were found for PCT and CRP. The combination of severity scores and each biomarker did not provide superior AUCs.

CONCLUSIONS

SuPAR and, to a lesser extent, proADM levels on ICU admission were better tools in prognosticating in-hospital mortality than CRP or PCT. However, neither of the two new biomarkers has been demonstrated to be excessively useful in the current setting. The prognostic accuracy was better for severity scores than for any of the biomarkers.

Peri-operative interventions, but not inflammatory mediators, increase risk of acute kidney injury after cardiac surgery: a prospective cohort study

PURPOSE

Cardiopulmonary bypass (CPB)-related inflammatory response might be one mechanism by which cardiac surgery associated acute kidney injury (CS-AKI) occurs. Interventions that may attenuate inflammation, including glucocorticoids or phosphodiesterase inhibitors, could therefore have a role in its prevention. We aimed to determine the role of inflammatory mediators in CS-AKI in children and the efficacy of commonly used peri-operative interventions to reduce CS-AKI risk.

METHODS

We prospectively studied 109 children undergoing heart surgery. Using regression modeling (adjusting for covariates), we (1) evaluated the association between inflammatory mediators [interleukin (IL)-6, IL-8, C-reactive protein, and tumor necrosis factor-α levels] and CS-AKI, and (2) evaluated risk/prevention factors for CS-AKI including glucocorticoid and milrinone administration. CS-AKI was defined based on pRIFLE methods.

RESULTS

CS-AKI occurred in 68% of children. No inflammatory mediator measured had an independent association with CS-AKI. Higher pre-operative glomerular filtration rate (GFR), sustained decrease in mean arterial pressure during CPB, post-operative single ventricle physiology, deep hypothermic circulatory arrest, and milrinone use at 24 h post-operatively were significant independent predictors of CS-AKI. Intra-operative steroid administration had no effect on the rate of CS-AKI.

CONCLUSIONS

Although inflammatory mediators are up-regulated following CPB, we found no association between levels of inflammatory cytokines and CS-AKI. CS-AKI has complex pathophysiology and the observation that milrinone was associated with increased AKI risk (and that higher GFR predicts more injury) suggests that mechanisms beyond inflammation play a significant role. Intra-operative administration of glucocorticoid does not appear to be an effective intervention for reducing the risk of CS-AKI.

Risk factors for hypoglycaemia in neurocritical care patients

PURPOSE

To identify risk factors for hypoglycaemia in neurocritical care patients receiving intensive insulin therapy (IIT).

METHODS

We performed a nested case-control study. All first episodes of hypoglycaemia (glucose <80 mg/dL, <4.4 mmol/L) in neurocritical care patients between 1 March 2006 and 31 December 2007 were identified. Patients were treated according to the local IIT protocol, with target blood glucose levels between 4.5 and 6.0 mmol/L (81.0-108.0 mg/dL). The first hypoglycaemic event of every patient (index moment) was used to match to a control patient. Possible risk factors preceding the index moment were scored using hospital records and analysed with conditional logistic regression.

RESULTS

Of 786 neurocritical care patients, 449 developed hypoglycaemia (57.1 %). Independent risk factors for hypoglycaemia were lowering nutrition 6 h before the index moment without insulin dose reduction (odds ratio (OR) 5.25, 95 % confidence interval (95 % CI) 1.32-20.88), mechanical ventilation (OR 2.59, 95 % CI 1.56-4.29), lowering the dosage of norepinephrine 3 h before the index moment (OR 2.44, 95 % CI 1.07-5.55), a hyperglycaemic event (>10 mmol/L, >180.0 mg/dL) in the 24 h preceding the index moment (OR 2.40, 95 % CI 1.26-4.58), gastric residual in the 6 h preceding the index moment without insulin dose reduction (OR 1.76, 95 % CI 1.05-2.96) and dosage of insulin at the index moment (OR 0.83, 95 % CI 0.76-0.90).

CONCLUSION

Hypoglycaemia occurs in a considerable proportion of neurocritical care patients. We recommend the identification of these risk factors in these patients to avoid the occurrence of hypoglycaemia.

Circulating nucleosomes as a predictor of sepsis and organ dysfunction in critically ill patients

OBJECTIVES

Sepsis is a leading cause of death in critically ill patients, and apoptosis plays a major role in the pathophysiology of sepsis. Elevated levels of circulating nucleosomes released by apoptotic cells have been detected in patients with severe sepsis and septic shock. The aim of this study was to evaluate the diagnostic/prognostic value of circulating nucleosomes in sepsis.

METHODS

Seventy-four newly admitted patients with an estimated length of stay in the intensive care unit of more than 48 h, were prospectively enrolled as cohort 1. The second independent cohort (cohort 2) consisted of 91 post-surgery patients. Patients receiving chemotherapy, those with AIDS, those on steroid treatment, and those undergoing transplants were excluded. Levels of circulating nucleosomes within 24h of admission in both cohorts, and for cohort 1 also on days 3, 5, and 7 and a last time-point of ICU discharge or at imminent death, were measured and analyzed for their capacity to predict sepsis. The severity of the inflammatory response and organ dysfunction were assessed by cytokine levels and sepsis scores.

RESULTS

Nucleosome levels on admission in septic patients were significantly higher than those in non-septic controls in both of the cohorts. The area under the receiver operating characteristic curve for admission nucleosome levels to differentiate septic patients from non-septic patients was 0.70 (95% confidence interval (CI) 0.51-0.88) in cohort 1, 0.66 (95% CI 0.55-0.79) in cohort 2, and 0.67 (95% CI 0.55-0.79) in all of the subjects. After multiple logistic regression analysis, circulating nucleosomes remained as an independent predictor of sepsis. Furthermore, the levels of circulating nucleosomes on admission were significantly correlated with the inflammatory response and organ dysfunction in sepsis. Meanwhile, a trend was observed for admission levels of circulating nucleosomes in non-survivors to be higher than those in survivors.

CONCLUSIONS

The level of circulating nucleosomes in the serum has a predictive value for sepsis and organ dysfunction and may serve as a candidate biomarker for the diagnosis/prognosis of sepsis. Further studies are warranted to confirm the present findings.

Gastrointestinal function in intensive care patients: terminology, definitions and management. Recommendations of the ESICM Working Group on Abdominal Problems

PURPOSE

Acute gastrointestinal (GI) dysfunction and failure have been increasingly recognized in critically ill patients. The variety of definitions proposed in the past has led to confusion and difficulty in comparing one study to another. An international working group convened to standardize the definitions for acute GI failure and GI symptoms and to review the therapeutic options.

METHODS

The Working Group on Abdominal Problems (WGAP) of the European Society of Intensive Care Medicine (ESICM) developed the definitions for GI dysfunction in intensive care patients on the basis of the available evidence and current understanding of the pathophysiology.

RESULTS

Definitions for acute gastrointestinal injury (AGI) with its four grades of severity, as well as for feeding intolerance syndrome and GI symptoms (e.g. vomiting, diarrhoea, paralysis, high gastric residual volumes) are proposed. AGI is a malfunctioning of the GI tract in intensive care patients due to their acute illness. AGI grade I = increased risk of developing GI dysfunction or failure (a self-limiting condition); AGI grade II = GI dysfunction (a condition that requires interventions); AGI grade III = GI failure (GI function cannot be restored with interventions); AGI grade IV = dramatically manifesting GI failure (a condition that is immediately life-threatening). Current evidence and expert opinions regarding treatment of acute GI dysfunction are provided.

CONCLUSIONS

State-of-the-art definitions for GI dysfunction with gradation as well as management recommendations are proposed on the basis of current medical evidence and expert opinion. The WGAP recommends using these definitions for clinical and research purposes.

Social integration: an important factor for health-related quality of life after critical illness

OBJECTIVES

To examine to what extent availability of social integration affects health-related quality of life (HRQoL) in former intensive care unit (ICU) patients and how it relates to corresponding findings in a general reference group.

DESIGN

Controlled, multicenter, prospective, explorative study.

SETTING AND PATIENTS

HRQoL data (SF-36) were collected from three combined medical and surgical ICUs in the south-east of Sweden. Social integration was assessed by the Availability of Social Integration (AVSI) instrument (seven questions related to the social interaction of the patient). As reference group, a random sample (n = 6,093) of people from the uptake area of the hospitals was used. Social integration (AVSI), HRQoL (SF-36), and comorbidity were examined also in the reference group.

INTERVENTIONS

None.

MEASUREMENTS AND RESULTS

The level of social integration significantly affected HRQoL for the former ICU patients, whereas no such effect was seen for the general reference group. For the ICU patients, social integration affected HRQoL to a larger extent than age, sex, and the ICU-related factors examined, but to a lower extent than the pre-existing diseases.

CONCLUSIONS

For a comprehensive assessment of HRQoL in former ICU patients, it is mandatory to include the effect of social integration.

A pulmonary aspergillosis case with fatal course in a patient with SIRS clinic

A 77-year-old male patient with a history of tuberculosis applied to emergency service with complaints of confusion, shortness of breath, tachycardia, hypothermia and hypotension. A bronchoalveolar lavage culture was collected because a fungus ball was seen on repeat chest X-ray and thoracic CT of the patient. Aspergillus fumigatus grew and voricona-zole treatment was started, but the patient was lost from multiple organ failure (MOF). In diagnosis of patients with SIRS clinic, causative factor may be aspergillus located in an old tuberculosis cavity, and this may have a fatal course in an old patient having previous pulmonary and systemic diseases.

Glucose variability measures and their effect on mortality: a systematic review

Objective

To systematically review the medical literature on the association between glucose variability measures and mortality in critically ill patients.

Methods

Studies assessing the association between a measure of glucose variability and mortality that reported original data from a clinical trial or observational study on critically ill adult patients were searched in Ovid MEDLINE^® and Ovid EMBASE^®. Data on patient populations, study designs, glucose regulations, statistical approaches, outcome measures, and glucose variability indicators (their definition and applicability) were extracted.

Result

Twelve studies met the inclusion criteria; 13 different indicators were used to measure glucose variability. Standard deviation and the presence of both hypo- and hyperglycemia were the most common indicators. All studies reported a statistically significant association between mortality and at least one glucose variability indicator. In four studies both blood glucose levels and severity of illness were considered as confounders, but only one of them checked model assumptions to assert inference validity.

Conclusions

Glucose variability has been quantified in many different ways, and in each study at least one of them appeared to be associated with mortality. Because of methodological limitations and the possibility of reporting bias, it is still unsettled whether and in which quantification this association is independent of other confounders. Future research will benefit from using an indicator reference subset for glucose variability, metrics that are linked more directly to negative physiological effects, more methodological rigor, and/or better reporting.