Profiling the dysregulated immune response in sepsis: overcoming challenges to achieve the goal of precision medicine

Sepsis is characterised by a dysregulated host immune response to infection. Despite recognition of its significance, immune status monitoring is not implemented in clinical practice due in part to the current absence of direct therapeutic implications. Technological advances in immunological profiling could enhance our understanding of immune dysregulation and facilitate integration into clinical practice. In this Review, we provide an overview of the current state of immune profiling in sepsis, including its use, current challenges, and opportunities for progress. We highlight the important role of immunological biomarkers in facilitating predictive enrichment in current and future treatment scenarios. We propose that multiple immune and non-immune-related parameters, including clinical and microbiological data, be integrated into diagnostic and predictive combitypes, with the aid of machine learning and artificial intelligence techniques. These combitypes could form the basis of workable algorithms to guide clinical decisions that make precision medicine in sepsis a reality and improve patient outcomes.

An exploratory research report on brain mineralization in postoperative delirium and cognitive decline

Delirium is a severe postoperative complication associated with poor overall and especially neurocognitive prognosis. Altered brain mineralization is found in neurodegenerative disorders but has not been studied in postoperative delirium and postoperative cognitive decline. We hypothesized that mineralization-related hypointensity in susceptibility-weighted magnetic resonance imaging (SWI) is associated with postoperative delirium and cognitive decline. In an exploratory, hypothesis-generating study, we analysed a subsample of cognitively healthy patients ≥65 years who underwent SWI before (N = 65) and 3 months after surgery (N = 33). We measured relative SWI intensities in the basal ganglia, hippocampus and posterior basal forebrain cholinergic system (pBFCS). A post hoc analysis of two pBFCS subregions (Ch4, Ch4p) was conducted. Patients were screened for delirium until the seventh postoperative day. Cognitive testing was performed before and 3 months after surgery. Fourteen patients developed delirium. After adjustment for age, sex, preoperative cognition and region volume, only pBFCS hypointensity was associated with delirium (regression coefficient [90% CI]: B = -15.3 [-31.6; -0.8]). After adjustments for surgery duration, age, sex and region volume, perioperative change in relative SWI intensities of the pBFCS was associated with cognitive decline 3 months after surgery at a trend level (B = 6.8 [-0.9; 14.1]), which was probably driven by a stronger association in subregion Ch4p (B = 9.3 [2.3; 16.2]). Brain mineralization, particularly in the cerebral cholinergic system, could be a pathomechanism in postoperative delirium and cognitive decline. Evidence from our studies is limited because of the small sample and a SWI dataset unfit for iron quantification, and the analyses presented here should be considered exploratory.

Value of hemophagocytosis in the diagnosis of hemophagocytic lymphohistiocytosis in critically ill patients

BACKGROUND

Ferritin is an established biomarker in the diagnosis of secondary hemophagocytic lymphohistiocytosis (HLH), which is diagnosed by the HLH-2004 criteria. Among these criteria, detection of hemophagocytosis through invasive procedures may delay early life saving treatment. Our aim was to investigate the value of hemophagocytosis in diagnosing HLH in critically ill patients.

METHODS

In this secondary analysis of a retrospective observational study, we included all patients aged ≥18 years and admitted to any adult ICU at Charité-Universitätsmedizin Berlin between January 2006 and August 2018, who had hyperferritinemia (≥500 μg/L) and underwent bone marrow biopsy during their ICU course.

RESULTS

Two hundred fifty-two patients were included, of whom 31 (12.3%) showed hemophagocytosis. In multivariable logistic regression analysis, maximum ferritin was independently associated with hemophagocytosis. By removing hemophagocytosis from HLH-2004 criteria and HScore, prediction accuracy for HLH diagnosis was only marginally decreased compared to the original scores.

CONCLUSIONS

Our results strengthen the diagnostic value of ferritin and underline the importance of considering HLH diagnosis in patients with high ferritin but only four fulfilled HLH-2004 criteria, when hemophagocytosis was not assessed or not detectable. Proof of hemophagocytosis is not required for a reliable HLH diagnosis.

Interdisciplinary perspectives on computed tomography in sepsis: survey among medical doctors at a large university medical center

OBJECTIVES

This study aims to describe physicians' perspectives on the use of computed tomography (CT) in patients with sepsis.

METHODS

In January 2022, physicians of a large European university medical center were surveyed using a web-based questionnaire asking about their views on the role of CT in sepsis. A total of 371 questionnaires met the inclusion criteria and were analyzed using work experience, workplace, and medical specialty of physicians as variables. Chi-square tests were performed.

RESULTS

Physicians considered the ability to detect an unknown focus as the greatest benefit of CT scans in sepsis (70.9%, n = 263/371). Two clinical criteria - "signs of decreased vigilance" (89.2%, n = 331/371) and "increased catecholamine demand" (84.7%, n = 314/371) - were considered highly relevant for a CT request. Elevated procalcitonin (82.7%, n = 307/371) and lactate levels (83.6%, n = 310/371) were consistently found to be critical laboratory values to request a CT. As long as there is evidence of infection in one organ region, most physicians (42.6%, n = 158/371) would order a CT scan based on clinical assessment. Combined examination of the chest, abdomen, and pelvis was favored (34.8%, n = 129/371) in cases without clinical clues of an infection source. A time window of ≥ 1-6 h was preferred for both CT examinations (53.9%, n = 200/371) and CT-guided interventions (59.3%, n = 220/371) in patients with sepsis.

CONCLUSION

Despite much consensus, there are significant differences in attitudes towards the use of CT in septic patients among physicians from different workplaces and medical specialties. Knowledge of these perspectives may improve patient management and interprofessional communication.

KEY POINTS

Despite interdisciplinary consensus on the use of CT in sepsis, statistically significant differences in the responses are apparent among physicians from different workplaces and medical specialties. The detection of a previously unknown source of infection and the ability to plan interventions and/or surgery based on CT findings are considered key advantages of CT in septic patients. Timing of CT reflects the requirements of specific disciplines.

Preoperative hypoalbuminaemia in liver surgery: an observational study at a university medical centre

OBJECTIVES

Preoperative hypoalbuminaemia is associated with adverse outcome, including increased postoperative mortality in cardiovascular surgery, neurosurgery, trauma and orthopaedic surgery. However, much less is known about the association between preoperative serum albumin and clinical outcomes after liver surgery. In this study, we sought to determine whether hypoalbuminaemia before partial hepatectomy is associated with a worse postoperative outcome.

DESIGN

Observational study.

SETTING

University Medical Centre in Germany.

PARTICIPANTS

We analysed 154 patients enrolled in the perioperative PHYsostigmine prophylaxis for liver resection patients at risk for DELIrium and postOperative cognitive dysfunction (PHYDELIO) trial with a preoperative serum albumin assessment. Hypoalbuminaemia was defined as serum albumin <35 g/L. Subgroups classified as hypoalbuminaemia and non-hypoalbuminaemia consisted of 32 (20.8%) and 122 (79.2%) patients, respectively.

OUTCOME MEASURES

The outcome parameters of interest were postoperative complications according to Clavien (moderate: I, II; major: ≥III), length of intensive care unit (ICU) stay, length of hospital stay and survival rates 1 year after surgery.

RESULTS

Preoperative hypoalbuminaemia was associated with the occurrence of major postoperative complications (OR 3.051 (95% CI 1.197 to 7.775); p=0.019) after adjusting for age, sex, randomisation, American Society of Anesthesiologists physical status, preoperative diagnosis and Child-Pugh class. Both ICU and hospital lengths of stay were significantly prolonged in patients with preoperative hypoalbuminaemia (OR 2.573 (95% CI 1.015 to 6.524); p=0.047 and OR 1.296 (95% CI 0.254 to 3.009); p=0.012, respectively). One-year survival was comparable between patients with and without hypoalbuminaemia.

CONCLUSIONS

We found that low serum albumin before surgery was associated with a worse short-term outcome after partial hepatectomy, which strengthens the prognostic value of serum albumin in the setting of liver surgery.

TRIAL REGISTRATION NUMBERS

ISRCTN18978802 and EudraCT 2008-007237-47.

Circadian Rhythm Disruption in Critically Ill Patients

Patients admitted to the intensive care unit (ICU) are in need of continuous organ replacement strategies and specialized care, e.g. because of neurological dysfunction, cardio-pulmonary instability, liver or kidney failure, trauma, hemorrhagic or septic shock or even preterm birth. The 24-hour nursing and care interventions provided to critically ill patients significantly limit resting and/or recovery phases. Consecutively, the patient's endogenous circadian rhythms are misaligned and disrupted, which in turn may interfere with their critical condition. A more thorough understanding of the complex interactions of circadian effectors and tissue-specific molecular clocks could therefore serve as potential means for enhancing personalized treatment in critically ill patients, conceivably restoring their circadian network and thus accelerating their physical and neurocognitive recovery. This review addresses the overarching issue of how circadian rhythms are affected and disturbed in critically ill newborns and adults in the ICU, and whether the conflicting external or environmental cues in the ICU environment further promote disruption and thus severity of illness. We direct special attention to the influence of cell-type specific molecular clocks on with severity of organ dysfunctions such as severity of brain dysfunction, pneumonia- or ventilator-associated lung inflammation, cardiovascular instability, liver and kidney failure, trauma, and septic shock. Finally, we address the potential of circadian rhythm stabilization to enhance and accelerate clinical recovery.

Postoperative delirium is associated with grey matter brain volume loss

Delirium is associated with long-term cognitive dysfunction and with increased brain atrophy. However, it is unclear whether these problems result from or predisposes to delirium. We aimed to investigate preoperative to postoperative brain changes, as well as the role of delirium in these changes over time. We investigated the effects of surgery and postoperative delirium with brain MRIs made before and 3 months after major elective surgery in 299 elderly patients, and an MRI with a 3 months follow-up MRI in 48 non-surgical control participants. To study the effects of surgery and delirium, we compared brain volumes, white matter hyperintensities and brain infarcts between baseline and follow-up MRIs, using multiple regression analyses adjusting for possible confounders. Within the patients group, 37 persons (12%) developed postoperative delirium. Surgical patients showed a greater decrease in grey matter volume than non-surgical control participants [linear regression: B (95% confidence interval) = -0.65% of intracranial volume (-1.01 to -0.29, P < 0.005)]. Within the surgery group, delirium was associated with a greater decrease in grey matter volume [B (95% confidence interval): -0.44% of intracranial volume (-0.82 to -0.06, P = 0.02)]. Furthermore, within the patients, delirium was associated with a non-significantly increased risk of a new postoperative brain infarct [logistic regression: odds ratio (95% confidence interval): 2.8 (0.7-11.1), P = 0.14]. Our study was the first to investigate the association between delirium and preoperative to postoperative brain volume changes, suggesting that delirium is associated with increased progression of grey matter volume loss.

Increased Direct Current-Electroencephalography Shifts During Induction of Anesthesia in Elderly Patients Developing Postoperative Delirium

Background

Changes in the direct current (DC) electroencephalography (EEG), so-called DC shifts, are observed during hypoxia, hypo-/hypercapnia, anesthetic administration, epileptic seizures, and spreading depolarizations. They are associated with altered cerebral ion currents across cell membranes and/or the blood–brain barrier (BBB). Here, we measured DC shifts in clinical practice during hyperventilation (HV) and anesthesia induction, and investigated whether such DC shifts correlate with the occurrence of postoperative delirium (POD) in older patients.

Methods

In this prospective observational study (subproject of the BioCog study, NCT02265263; EA2/092/14), a continuous pre- and perioperative DC-EEG was recorded in patients aged ≥65 years. The preoperative DC-EEG included a 2 min HV with simultaneous measurement of end-tidal CO₂. Of the perioperative recordings, DC-EEG segments were chosen from a 30 s period at the start of induction of anesthesia (IOA), loss of consciousness (LOC), and during a stable anesthetic phase 30 min after skin incision (intraOP). The DC shift at Cz was determined in μV/s. All patients were screened twice daily for the first seven postoperative days for the occurrence of POD. DC-EEG shifts were compared in patients with (POD) and without postoperative delirium (noPOD).

Results

Fifteen patients were included in this subproject of the BioCog study. DC shifts correlated significantly with concurrent HV, with DC shifts increasing the more end-tidal CO₂ decreased (P = 0.001, Spearman’s rho 0.862). During the perioperative DC-EEG, the largest DC shift was observed at LOC during IOA. POD patients (n = 8) presented with significantly larger DC shifts at LOC [POD 31.6 (22.7; 38.9) μV/s vs. noPOD 4.7 (2.2; 12.5) μV/s, P = 0.026].

Conclusion

DC shifts can be observed during HV and IOA in routine clinical practice. At anesthesia induction, the DC shift was greatest at the time of LOC, with POD patients presenting with significantly stronger DC shifts. This could indicate larger changes in gas tensions, hypotension and impaired cerebral autoregulation or BBB dysfunction in these patients.

Clinical Trial Registration

www.clinicaltrials.gov, identifier NCT02265263.

Die hämophagozytische Lymphohistiozytose bei kritisch kranken Patienten

Bei der hämophagozytischen Lymphohistiozytose (HLH) handelt es sich um ein Hyperinflammationssyndrom bedingt durch aberrant aktivierte Makrophagen und T‑Zellen. Beim Erwachsenen ist in erster Linie die erworbene Form anzutreffen. Häufige Auslöser sind Infektionen, Malignome und Autoimmunerkrankungen. Zuletzt wurden zudem zunehmend Fälle berichtet, in denen das Auftreten im Zusammenhang mit stattgehabten Immuntherapien zu sehen war. Auf der Intensivstation ist die HLH aufgrund des ähnlichen klinischen Erscheinungsbilds oft schwer von der Sepsis abzugrenzen. Zum Teil liegen beide zeitgleich vor. Die frühzeitige Diagnosestellung und Einleitung einer adäquaten immunsuppressiven Therapie ist für den weiteren Verlauf und die Prognose der HLH essenziell. Deshalb muss bei kritisch kranken Patienten mit persistierendem Fieber und entsprechenden Symptomen (z. B. Splenomegalie, neurologische Auffälligkeiten) oder Laborveränderungen (z. B. erhöhter Ferritinwert, Zytopenie von 2 oder 3 Zellreihen, erhöhte Transaminasen) das Vorliegen einer HLH in Betracht gezogen werden. Die Diagnose wird mithilfe der HLH-2004-Kriterien gestellt. Mit dem HScore kann die Wahrscheinlichkeit des Vorliegens einer HLH berechnet werden. Hochdosierte Kortikosteroide stellen den Grundpfeiler der HLH-Therapie dar. Je nach Auslöser werden Etoposid, Immunglobuline, Anakinra oder weitere Medikamente ergänzt. Der Verlauf hängt neben einem frühzeitigen Behandlungsbeginn vom Auslöser sowie dem Ansprechen auf die Therapie ab. Insgesamt ist die Prognose der HLH trotz maximaler intensivmedizinischer Behandlung ungünstig und sie ist mit einer hohen Letalität assoziiert.

The COVID-19 puzzle: deciphering pathophysiology and phenotypes of a new disease entity

The zoonotic SARS-CoV-2 virus that causes COVID-19 continues to spread worldwide, with devastating consequences. While the medical community has gained insight into the epidemiology of COVID-19, important questions remain about the clinical complexities and underlying mechanisms of disease phenotypes. Severe COVID-19 most commonly involves respiratory manifestations, although other systems are also affected, and acute disease is often followed by protracted complications. Such complex manifestations suggest that SARS-CoV-2 dysregulates the host response, triggering wide-ranging immuno-inflammatory, thrombotic, and parenchymal derangements. We review the intricacies of COVID-19 pathophysiology, its various phenotypes, and the anti-SARS-CoV-2 host response at the humoral and cellular levels. Some similarities exist between COVID-19 and respiratory failure of other origins, but evidence for many distinctive mechanistic features indicates that COVID-19 constitutes a new disease entity, with emerging data suggesting involvement of an endotheliopathy-centred pathophysiology. Further research, combining basic and clinical studies, is needed to advance understanding of pathophysiological mechanisms and to characterise immuno-inflammatory derangements across the range of phenotypes to enable optimum care for patients with COVID-19.

Circadian rhythms in septic shock patients

BACKGROUND

Despite the intensive efforts to improve the diagnosis and therapy of sepsis over the last decade, the mortality of septic shock remains high and causes substantial socioeconomical burden of disease. The function of immune cells is time-of-day-dependent and is regulated by several circadian clock genes. This study aims to investigate whether the rhythmicity of clock gene expression is altered in patients with septic shock.

METHODS

This prospective pilot study was performed at the university hospital Charité-Universitätsmedizin Berlin, Department of Anesthesiology and Operative Intensive Care Medicine (CCM, CVK). We included 20 patients with septic shock between May 2014 and January 2018, from whom blood was drawn every 4 h over a 24-h period to isolate CD14-positive monocytes and to measure the expression of 17 clock and clock-associated genes. Of these patients, 3 whose samples expressed fewer than 8 clock genes were excluded from the final analysis. A rhythmicity score SP was calculated, which comprises values between -1 (arrhythmic) and 1 (rhythmic), and expression data were compared to data of a healthy study population additionally.

RESULTS

77% of the measured clock genes showed inconclusive rhythms, i.e., neither rhythmic nor arrhythmic. The clock genes NR1D1, NR1D2 and CRY2 were the most rhythmic, while CLOCK and ARNTL were the least rhythmic. Overall, the rhythmicity scores for septic shock patients were significantly (p < 0.0001) lower (0.23 ± 0.26) compared to the control group (12 healthy young men, 0.70 ± 0.18). In addition, the expression of clock genes CRY1, NR1D1, NR1D2, DBP, and PER2 was suppressed in septic shock patients and CRY2 was significantly upregulated compared to controls.

CONCLUSION

Molecular rhythms in immune cells of septic shock patients were substantially altered and decreased compared to healthy young men. The decrease in rhythmicity was clock gene-dependent. The loss of rhythmicity and down-regulation of clock gene expression might be caused by sepsis and might further deteriorate immune responses and organ injury, but further studies are necessary to understand underlying pathophysiological mechanisms. Trail registration Clinical trial registered with www.ClinicalTrials.gov (NCT02044575) on 24 January 2014.

Bridging animal and clinical research during SARS-CoV-2 pandemic: A new-old challenge

Many milestones in medical history rest on animal modeling of human diseases. The SARS-CoV-2 pandemic has evoked a tremendous investigative effort primarily centered on clinical studies. However, several animal SARS-CoV-2/COVID-19 models have been developed and pre-clinical findings aimed at supporting clinical evidence rapidly emerge. In this review, we characterize the existing animal models exposing their relevance and limitations as well as outline their utility in COVID-19 drug and vaccine development. Concurrently, we summarize the status of clinical trial research and discuss the novel tactics utilized in the largest multi-center trials aiming to accelerate generation of reliable results that may subsequently shape COVID-19 clinical treatment practices. We also highlight areas of improvement for animal studies in order to elevate their translational utility. In pandemics, to optimize the use of strained resources in a short time-frame, optimizing and strengthening the synergy between the preclinical and clinical domains is pivotal.

Critical illness myopathy precedes hyperglycaemia and high glucose variability

BACKGROUND

Critical Illness Myopathy (CIM) is a serious ICU complication, and dysglycaemia is widely regarded as a risk factor. Although glucose variability (GV) has been independently linked to ICU mortality, an association with CIM has not been investigated. This study examines the relationship between CIM and GV.

METHODS

Retrospective investigation including ICU patients with SOFA ≥8, mechanical ventilation, and CIM diagnostics. Glucose readings were collected every 6 h throughout the first week of treatment, when CIM is thought to develop. GV was measured using standard deviation (SD), coefficient of variability (CV), mean absolute glucose (MAG), mean amplitude of glycaemic excursions (MAGE), and mean of daily difference (MODD).

RESULTS

74 patients were included, and 50 (67.6%) developed CIM. Time on glycaemic target (70-179 mg/dL), caloric and insulin intakes, mean, maximum and minimum blood glucose values were similar for all patients until the 5th day, after which CIM patients exhibited higher mean and maximum glucose levels. Significantly higher GV in CIM patients were observed on day 5 (SD, CV, MAG, MAGE), day 6 (MODD), and day 7 (SD, CV, MAG).

CONCLUSIONS

CIM patients developed transient increases in GV and hyperglycaemia only late in the first week, suggesting that myopathy precedes dysglycaemia.

The association between intraoperative hyperglycemia and cerebrovascular markers

BACKGROUND AND PURPOSE: Hyperglycemia can lead to an increased rate of apoptosis of microglial cells and to damaged neurons. The relation between hyperglycemia and cerebrovascular markers on MRI is unknown. Our aim was to study the association between intraoperative hyperglycemia and cerebrovascular markers. METHODS: In this further analysis of a subgroup investigation of the BIOCOG study, 65 older non-demented patients (median 72 years) were studied who underwent elective surgery of ≥ 60 minutes. Intraoperative blood glucose maximum was determined retrospectively in each patient. In these patients, preoperatively and at 3 months follow-up a MRI scan was performed and white matter hyperintensity (WMH) volume and shape, infarcts, and perfusion parameters were determined. Multivariable logistic regression analyses were performed to determine associations between preoperative cerebrovascular markers and occurrence of intraoperative hyperglycemia. Linear regression analyses were performed to assess the relation between intraoperative hyperglycemia and pre- to postoperative changes in WMH volume. Associations between intraoperative hyperglycemia and postoperative WMH volume at 3 months follow-up were also assessed by linear regression analyses. RESULTS: Eighteen patients showed intraoperative hyperglycemia (glucose maximum ≥ 150 mg/dL). A preoperative more smooth shape of periventricular and confluent WMH was related to the occurrence of intraoperative hyperglycemia [convexity: OR 33.318 (95 % CI (1.002 - 1107.950); p = 0.050]. Other preoperative cerebrovascular markers were not related to the occurrence of intraoperative hyperglycemia. Intraoperative hyperglycemia showed no relation with pre- to postoperative changes in WMH volume nor with postoperative WMH volume at 3 months follow-up. CONCLUSIONS: We found that a preoperative more smooth shape of periventricular and confluent WMH was related to the occurrence of intraoperative hyperglycemia. These findings may suggest that a similar underlying mechanism leads to a certain pattern of vascular brain abnormalities and an increased risk of hyperglycemia.

Epidural Anesthesia in Liver Surgery-A Propensity Score-Matched Analysis

OBJECTIVE

To assess the effects of epidural anesthesia (EA) on patients who underwent liver resection.

DESIGN

Secondary analysis of a prospective randomized controlled trial.

SETTING

This single-center study was conducted at an academic medical center.

METHODS

A subset of 110 1:1 propensity score-matched patients who underwent liver resection with and without EA were analyzed. Outcome measures were pain intensity ≥5 on a numeric rating scale (NRS) at rest and during movement on postoperative days 1-5, analyzed with logistic mixed-effects models, and postoperative complications according to the Clavien-Dindo classification, length of hospital stay (LOS), and one-year survival. One-year survival in the matched cohorts was compared using a frailty model.

RESULTS

EA patients were less likely to experience NRS ≥5 at rest (odds ratio = 0.06, 95% confidence interval [CI] = 0.01 to 0.28, P < 0.001). These findings were independent of age, sex, Charlson comorbidity index, baseline NRS, and surgical approach (open vs laparoscopic). The number and severity of postoperative complications and LOS were comparable between groups (P = 0.258, P > 0.999, and P = 0.467, respectively). Reduced mortality rates were seen in the EA group one year after surgery (9.1% vs 30.9%, hazard ratio = 0.32, 95% CI = 0.11 to 0.90, P = 0.031). No EA-related adverse events occurred. Earlier recovery of bowel function was seen in EA patients.

CONCLUSIONS

Patients with EA had better postoperative pain control and required fewer systemic opioids. Postoperative complications and LOS did not differ, although one-year survival was significantly improved in patients with EA. EA applied in liver surgery was effective and safe.

Hemophagocytic lymphohistiocytosis in critically ill patients: diagnostic reliability of HLH-2004 criteria and HScore

BACKGROUND

Hemophagocytic lymphohistiocytosis (HLH) is a rare though often fatal hyperinflammatory syndrome mimicking sepsis in the critically ill. Diagnosis relies on the HLH-2004 criteria and HScore, both of which have been developed in pediatric or adult non-critically ill patients, respectively. Therefore, we aimed to determine the sensitivity and specificity of HLH-2004 criteria and HScore in a cohort of adult critically ill patients.

METHODS

In this further analysis of a retrospective observational study, patients ≥ 18 years admitted to at least one adult ICU at Charité - Universitätsmedizin Berlin between January 2006 and August 2018 with hyperferritinemia of ≥ 500 μg/L were included. Patients' charts were reviewed for clinically diagnosed or suspected HLH. Receiver operating characteristics (ROC) analysis was performed to determine prediction accuracy.

RESULTS

In total, 2623 patients with hyperferritinemia were included, of whom 40 patients had HLH. We found the best prediction accuracy of HLH diagnosis for a cutoff of 4 fulfilled HLH-2004 criteria (95.0% sensitivity and 93.6% specificity) and HScore cutoff of 168 (100% sensitivity and 94.1% specificity). By adjusting HLH-2004 criteria cutoffs of both hyperferritinemia to 3000 μg/L and fever to 38.2 °C, sensitivity and specificity increased to 97.5% and 96.1%, respectively. Both a higher number of fulfilled HLH-2004 criteria [OR 1.513 (95% CI 1.372-1.667); p <  0.001] and a higher HScore [OR 1.011 (95% CI 1.009-1.013); p <  0.001] were significantly associated with in-hospital mortality.

CONCLUSIONS

An HScore cutoff of 168 revealed a sensitivity of 100% and a specificity of 94.1%, thereby providing slightly superior diagnostic accuracy compared to HLH-2004 criteria. Both HLH-2004 criteria and HScore proved to be of good diagnostic accuracy and consequently might be used for HLH diagnosis in critically ill patients.

CLINICAL TRIAL REGISTRATION

The study was registered with www.ClinicalTrials.gov (NCT02854943) on August 1, 2016.

Perioperatively Acquired Weakness

BACKGROUND

Skeletal muscle failure in critical illness (intensive care unit-acquired weakness) is a well-known complication developing early during intensive care unit stay. However, muscle weakness during the perioperative setting has not yet been investigated.

METHODS

We performed a subgroup investigation of a prospective observational trial to investigate perioperative muscle weakness. Eighty-nine patients aged 65 years or older were assessed for handgrip strength preoperatively, on the first postoperative day, at intensive care unit discharge, at hospital discharge, and at 3-month follow-up. Functional status was evaluated perioperatively via Barthel index, instrumental activities of daily living, Timed Up and Go test, and functional independence measure. After exclusion of patients with intensive care unit-acquired weakness or intensive care unit stay of ≥72 hours, 59 patients were included into our analyses. Of these, 14 patients had additional pulmonary function tests preoperatively and on postoperative day 1. Blood glucose was measured intraoperatively every 20 minutes.

RESULTS

Handgrip strength significantly decreased after surgery on postoperative day 1 by 16.4% (P < .001). Postoperative pulmonary function significantly decreased by 13.1% for vital capacity (P = .022) and 12.6% for forced expiratory volume in 1 second (P = .001) on postoperative day 1. Handgrip strength remained significantly reduced at hospital discharge (P = .016) and at the 3-month follow-up (P = .012). Perioperative glucose levels showed no statistically significant impact on muscle weakness. Instrumental activities of daily living (P < .001) and functional independence measure (P < .001) were decreased at hospital discharge, while instrumental activities of daily living remained decreased at the 3-month follow-up (P = .026) compared to preoperative assessments.

CONCLUSIONS

Perioperatively acquired weakness occurred, indicated by a postoperatively decreased handgrip strength, decreased respiratory muscle function, and impaired functional status, which partly remained up to 3 months.

Hyperferritinemia in Critically Ill Patients

OBJECTIVE

Hyperferritinemia is frequently seen in critically ill patients. A rather rare though life-threatening condition related to severely elevated ferritin is hemophagocytic lymphohistiocytosis. We analyze ferritin levels to differentiate hemophagocytic lymphohistiocytosis from other causes of hyperferritinemia in a mixed cohort of critically ill patients.

DESIGN

Retrospective observational study.

SETTING

Adult surgical, anesthesiologic, and medical ICUs of a university hospital.

PATIENTS

Critical care patients (≥ 18 yr old) admitted to any of the adult ICUs at Charité - Universitätsmedizin Berlin between January 2006 and August 2018 with at least one ferritin value and hyperferritinemia (≥ 500 µg/L).

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Patients were categorized into hemophagocytic lymphohistiocytosis, sepsis, septic shock, and other diagnoses. These were further categorized into 17 subgroups. Hemophagocytic lymphohistiocytosis diagnosis was based on Hemophagocytic Lymphohistiocytosis-2004 criteria and the HScore. Of 2,623 patients with hyperferritinemia, 40 were considered to have hemophagocytic lymphohistiocytosis (1.52%). Maximum ferritin levels were highest in hemophagocytic lymphohistiocytosis patients compared with all other disease groups (each p < 0.001). Sepsis and septic shock patients had higher maximum ferritin levels than patients with other diagnoses (each p < 0.001). A maximum ferritin value of 9,083 µg/L was at 92.5% sensitivity and 91.9% specificity for hemophagocytic lymphohistiocytosis (area under the curve, 0.963; 95% CI, 0.949-0.978). Of all subgroups with other diagnoses, maximum ferritin levels were highest in patients with varicella-zoster virus, hepatitis, or malaria (median, 1,935, 1,928, and 1,587 µg/L, respectively). Maximum ferritin levels were associated with increased in-hospital mortality (odds ratio, 1.518 per log µg/L [95% CI, 1.384-1.665 per log µg/L]; p < 0.001).

CONCLUSIONS

This is the largest study of patients with ferritin available in a mixed ICU cohort. Ferritin levels in patients with hemophagocytic lymphohistiocytosis, sepsis, septic shock, and other conditions were distinctly different, with the highest ferritin levels observed in hemophagocytic lymphohistiocytosis patients. Maximum ferritin of 9,083 µg/L showed high sensitivity and specificity and, therefore, may contribute to improved diagnosis of hemophagocytic lymphohistiocytosis in ICU. The inclusion of ferritin into the sepsis laboratory panel is warranted.

The History of Biomarkers: How Far Have We Come?

Sepsis is one of the oldest and most elusive syndromes in medicine that is still incompletely understood. Biomarkers may help to transform sepsis from a physiologic syndrome to a group of distinct biochemical disorders. This will help to differentiate between systemic inflammation of infectious and noninfectious origin and aid therapeutic decision making, hence improve the prognosis for patients, guide antimicrobial therapy, and foster the development of novel adjunctive sepsis therapies. To reach this goal requires increased systematic investigation that includes twenty-first century scientific approaches and technologies and appropriate clinical evaluation.

C-reactive protein for risk prediction of post-operative delirium and post-operative neurocognitive disorder

BACKGROUND

Post-operative delirium (POD) and post-operative neurocognitive disorder (NCD) are frequently seen in the elderly. Development of biomarkers for pre-operative risk prediction is of major relevance. As inflammation present before surgery might predispose to POD and post-operative NCD development, we aim to determine associations between pre-operative C-reactive protein (CRP) and the incidence of POD and post-operative NCD.

METHODS

In this observational study, we analyzed 314 patients enrolled in the SuDoCo trial, who had a pre-operative CRP measurement the day before surgery. Primary outcomes were POD assessed according DSM-4 from day 1 until day 7 after surgery and post-operative NCD assessed 3 months after surgery. We conducted multivariable logistic regression analysis adjusted for age, sex, randomization, body mass index, MMSE, ASA status, infection/autoimmune disease/malignoma and types of surgery to determine associations between CRP with POD and post-operative NCD, respectively.

RESULTS

Pre-operative CRP was independently associated with POD [OR 1.158 (95% CI 1.040, 1.291); P = .008]. Patients with CRP values ≥5 mg/dL had a 4.8-fold increased POD risk [OR 4.771 (95% CI 1.765, 12.899; P = .002)] compared to patients with lower CRP values. However, no association was seen between pre-operative CRP and post-operative NCD [OR 0.552 (95% CI 0.193, 1.581); P = .269].

CONCLUSIONS

Pre-operative CRP levels were independently associated with POD but not post-operative NCD after three months. Moreover, higher pre-operative CRP levels showed higher risk for POD. This strengthens the role of inflammation in the development of POD. Assessment of CRP before surgery might allow risk stratification of POD.

TRIAL REGISTRATION

This study was registered with ISRCTN Register 36437985 on 02 March 2009.

Diagnostic biomarkers for adult haemophagocytic lymphohistiocytosis in critically ill patients (HEMICU): a prospective observational study protocol

INTRODUCTION

Haemophagocytic lymphohistiocytosis (HLH) in adults is characterised by toxic immune activation and a sepsis-like syndrome, leading to high numbers of undiagnosed cases and mortality rates of up to 68%. Early diagnosis and specific immune suppressive treatment are mandatory to avoid fatal outcome, but the diagnostic criteria (HLH-2004) are adopted from paediatric HLH and have not been validated in adults. Experimental studies suggest biomarkers to sufficiently diagnose HLH. However, biomarkers for the diagnosis of adult HLH have not yet been investigated.

METHODS AND ANALYSIS

The HEMICU (Diagnostic biomarkers for adult haemophagocytic lymphohistiocytosis in critically ill patients) study aims to estimate the incidence rate of adult HLH among suspected adult patients in intensive care units (ICUs). Screening for HLH will be performed in 16 ICUs of Charité - Universitätsmedizin Berlin. The inclusion criteria are bicytopaenia, hyperferritinaemia (≥500 µg/L), fever or when HLH is suspected by the clinician. Over a period of 2 years, we expect inclusion of about 100 patients with suspected HLH. HLH will be diagnosed if at least five of the HLH-2004 criteria are fulfilled, together with an expert review; all other included patients will serve as controls. Second, a panel of potential biomarker candidates will be explored. DNA, plasma and serum will be stored in a biobank. The primary endpoint of the study is the incidence rate of adult HLH among suspected adult patients during ICU stay. Out of a variety of measured biomarkers, this study furthermore aims to find highly potential biomarkers for the diagnosis of adult HLH in ICU. The results of this study will contribute to improved recognition and patient outcome of adult HLH in clinical routine.

ETHICS AND DISSEMINATION

The institutional ethics committee approved this study on 1 August 2018 (Ethics Committee of Charité - Universitätsmedizin Berlin, EA4/006/18). The results of the study will be disseminated in an international peer-reviewed journal and presented at international conferences.

TRIAL REGISTRATION NUMBER

NCT03510650.

Intraoperative hyperglycemia increases the incidence of postoperative delirium

BACKGROUND

Hyperglycemia frequently occurs during major surgery and is associated with adverse postoperative outcomes. This study aimed to investigate the influence of intraoperative hyperglycemia on incidences of postoperative delirium (POD) and postoperative cognitive dysfunction (POCD).

METHODS

Eighty-seven patients aged ≥65 years undergoing elective surgery were included in this prospective observational subproject of the BioCog study. Blood glucose (BG) levels were measured every 20 minutes intraoperatively. Hyperglycemia was defined as BG levels ≥150 mg·dL-1. Patients were assessed for POD twice daily until postoperative day 7. The occurrence of POCD was determined three months after surgery. Multivariable logistic regression was used to identify associations between hyperglycemia and POD as well as POCD. Secondary endpoints comprised duration of hyperglycemia, maximum glucose level (Glucosemax) and differences between diabetic and non-diabetic patients.

RESULTS

POD occurred in 41 (47.1%), POCD in five (15.2%) patients. In two separate multivariable logistic regression models, hyperglycemia was significantly associated with POD (OR 3.86 [CI 95% 1.13, 39.49], P=0.044) but not POCD (3.59 [NaN, NaN], P=0.157). Relative duration of hyperglycemia was higher in POD patients compared to patients without POD (20 [0; 71] % versus 0 [0; 55] %, P=0.075), whereas the maximum glucose levels during surgery were similar between the two groups. Considering only non-diabetic patients, relative duration of hyperglycemia (P=0.003) and Glucosemax (P=0.015) were significantly higher in patients with POD.

CONCLUSIONS

Intraoperative hyperglycemia was independently associated with POD but not POCD. Relative duration of hyperglycemia appeared thereby to also play a role. Especially hyperglycemic non-diabetic patients might be at high risk for POD.

Diabetes, but Not Hypertension and Obesity, Is Associated with Postoperative Cognitive Dysfunction

BACKGROUND/AIMS

Older people undergoing surgery are at risk of developing postoperative cognitive dysfunction (POCD), but little is known of risk factors predisposing patients to POCD. Our objective was to estimate the risk of POCD associated with exposure to preoperative diabetes, hypertension, and obesity.

METHODS

Original data from 3 randomised controlled trials (OCTOPUS, DECS, SuDoCo) were obtained for secondary analysis on diabetes, hypertension, baseline blood pressure, obesity (BMI ≥30 kg/m2), and BMI as risk factors for POCD in multiple logistic regression models. Risk estimates were pooled across the 3 studies.

RESULTS

Analyses totalled 1,034 patients. POCD occurred in 5.2% of patients in DECS, in 9.4% in SuDoCo, and in 32.1% of patients in OCTOPUS. After adjustment for age, sex, surgery type, randomisation, obesity, and hypertension, diabetes was associated with a 1.84-fold increased risk of POCD (OR 1.84; 95% CI 1.14, 2.97; p = 0.01). Obesity, BMI, hypertension, and baseline blood pressure were each not associated with POCD in fully adjusted models (all p > 0.05).

CONCLUSION

Diabetes, but not obesity or hypertension, is associated with increased POCD risk. Consideration of diabetes status may be helpful for risk assessment of surgical patients.

Risk Factors of Intraoperative Dysglycemia in Elderly Surgical Patients

BACKGROUNDː Dysglycemia is associated with adverse outcome including increased morbidity and mortality in surgical patients. Acute insulin resistance due to the surgical stress response is seen as a major cause of so-called stress hyperglycemia. However, understanding of factors determining blood glucose (BG) during surgery is limited. Therefore, we investigated risk factors contributing to intraoperative dysglycemia. METHODSː In this subgroup investigation of the BIOCOG study, we analyzed 87 patients of ≥ 65 years with tight intraoperative BG measurement every 20 min during elective surgery. Dysglycemia was defined as at least one intraoperative BG measurement outside the recommended target range of 80-150 mg/dL. Additionally, all postoperative BG measurements in the ICU were obtained. Multivariable logistic regression analysis adjusted for age, sex, American Society of Anesthesiologists (ASA) status, diabetes, type and duration of surgery, minimum Hemoglobin (Hb) and mean intraoperative norepinephrine use was performed to identify risk factors of intraoperative dysglycemia. RESULTSː 46 (52.9%) out of 87 patients developed intraoperative dysglycemia. 31.8% of all intraoperative BG measurements were detected outside the target range. Diabetes [OR 9.263 (95% CI 2.492, 34.433); p=0.001] and duration of surgery [OR 1.005 (1.000, 1.010); p=0.036] were independently associated with the development of intraoperative dysglycemia. Patients who experienced intraoperative dysglycemia had significantly elevated postoperative mean (p<0.001) and maximum BG levels (p=0.001). Length of ICU (p=0.007) as well as hospital stay (p=0.012) were longer in patients with dysglycemia. CONCLUSIONSː Diabetes and duration of surgery were confirmed as independent risk factors for intraoperative dysglycemia, which was associated with adverse outcome. These patients, therefore, might require intensified glycemic control. Increased awareness and management of intraoperative dysglycemia is warranted.

Impact of Intraoperative Hyperglycemia on Brain Structures and Volumes

BACKGROUND AND PURPOSE

In hyperglycemic patients, who succumbed to septic shock, an increased rate of apoptosis of microglial cells and damaged neurons of the hippocampus were found. However, the influence of perioperative glucose levels on hippocampal brain structures has not yet been investigated.

METHODS

As part of the ongoing BIOCOG project, a subgroup of N = 65 elderly nondemented patients were analyzed who underwent elective surgery of ≥60 minutes. In these patients, at least one intraoperative blood glucose (BG) measurement was available from the medical charts. Intraoperative glucose maximum was determined in each patient. Preoperatively and at 3 months follow-up, structural neuroimaging was performed with T1-weighted magnetization prepared rapid gradient-echo sequence (MP-Rage) and a dedicated high-resolution hippocampus magnetic resonance imaging (MRI). The MRI scans were analyzed to assess pre- or postoperative volume changes of the hippocampus as a whole and hippocampal subfields. We also assessed changes of frontal lobe volume and cortical thickness.

RESULTS

Overall, 173 intraoperative BG levels were obtained in 65 patients (median 2 per patient). A total of 18 patients showed intraoperative hyperglycemia (glucose maximum ≥150 mg/dL). Controlling for age and diabetes status, no significant impact of intraoperative hyperglycemia was found on the pre-post volume change of the hippocampus as a whole, hippocampal subfields, frontal lobe, and frontal cortical thickness.

CONCLUSIONS

This study found no effect of intraoperative hyperglycemia on postoperative brain structures and volumes including volumes of hippocampus and hippocampal subfields, frontal lobe, and frontal cortical thickness. Further studies investigating the impact of intraoperatively elevated glucose levels should consider a tighter or even continuous glycemic measurement and the determination of central microglial activation.

Association of obesity, diabetes and hypertension with cognitive impairment in older age

Background

Age-related cognitive impairment is rising in prevalence but is not yet fully characterized in terms of its epidemiology. Here, we aimed to elucidate the role of obesity, diabetes and hypertension as candidate risk factors.

Methods

Original baseline data from 3 studies (OCTOPUS, DECS, SuDoCo) were obtained for secondary analysis of cross-sectional associations of diabetes, hypertension, blood pressure, obesity (body mass index [BMI] ≥30 kg/m²) and BMI with presence of cognitive impairment in log-binomial regression analyses. Cognitive impairment was defined as scoring more than 2 standard deviations below controls on at least one of 5–11 cognitive tests. Underweight participants (BMI<18.5 kg/m²) were excluded. Results were pooled across studies in fixed-effects inverse variance models.

Results

Analyses totaled 1545 participants with a mean age of 61 years (OCTOPUS) to 70 years (SuDoCo). Cognitive impairment was found in 29.0% of participants in DECS, 8.2% in SuDoCo and 45.6% in OCTOPUS. In pooled analyses, after adjustment for age, sex, diabetes and hypertension, obesity was associated with a 1.29-fold increased prevalence of cognitive impairment (risk ratio [RR] 1.29; 95% CI 0.98, 1.72). Each 1 kg/m² increment in BMI was associated with 3% increased prevalence (RR 1.03; 95% CI 1.00, 1.06). None of the remaining risk factors were associated with impairment.

Conclusion

Our results show that older people who are obese have higher prevalence of cognitive impairment compared with normal weight and overweight individuals, and independently of co-morbid hypertension or diabetes. Prospective studies are needed to investigate the temporal relationship of the association.

Innate immunity recovers earlier than acquired immunity during severe postoperative immunosuppression

Background: Postoperative immune suppression, particularly a loss of cell-mediated immunity, is commonly seen after surgery and is associated with worse outcome, i.e. delayed wound healing, infections, sepsis, multiple-organ failure and cancer recurrence. However, the recovery of immune cells focusing on differences between innate and acquired immunity during severe postoperative immunosuppression is not investigated. Methods: In this retrospective randomized controlled trial (RCT) subgroup analysis, 10 postoperatively immune suppressed patients after esophageal or pancreatic resection were analyzed. Innate and acquired immune cells, the expression of human leukocyte antigen-D related on monocytes (mHLA-DR), lipopolysaccharide (LPS)-induced monocytic TNF-α and IL-10 secretion ex vivo, Concanavalin A (Con A)-induced IFN-γ, TNF-α, IL-2, IL-4, IL-5 and IL-10 release were measured preoperatively (od) until day 5 after surgery (pod5). Recovery of immune cells was defined by a significant decrease respectively increase after a significant postoperative alteration. Statistical analyses were performed using nonparametric statistical procedures. Results: Postoperative alterations of innate immune cells recovered on pod2 (eosinophils), pod3 (neutrophils) and pod5 (mHLA-DR, monocytic TNF-α and IL-10 secretion), whereas alterations of acquired immune cells (lymphocytes, T cells, T helper cells, and cytotoxic T cells) did not recover until pod5. Peripheral blood T cells showed an impaired production of the T helper (Th) 1 cytokine IFN-γ upon Con A stimulation on pod1, while Th2 specific cytokine release did not change until pod5.Conclusions: Innate immunity recovered earlier than acquired immunity during severe postoperative immunosuppression. Furthermore, we found a more anti- than pro-inflammatory T cell function on the first day after surgery, while T cell counts decreased.

Severe perioperative hyperglycemia attenuates postoperative monocytic function, basophil count and T cell activation

BACKGROUND

Hyperglycemia in hospitalized patients is associated with increased morbidity and mortality. Postoperative infections are particularly common in the setting of perioperative hyperglycemia; however, the relationship between perioperative glucose levels and the innate immune system remains unclear.

METHODS

Immune cells, monocytic respectively T cell function and T cell subspecies of 32 patients after esophageal or pancreatic resection were analyzed preoperatively and on the first day after surgery (POD 1). Perioperative blood glucose was measured hourly via arterial blood gas analyses. Groups were classified by maximum perioperative glucose levels: <180 mg/dL versus at least one episode of ≥180 mg/dL. The suppression of immune cells and cytokines was defined as the difference between pre- and postoperative values.

RESULTS

In perioperative hyperglycemic patients, preoperative CD4+/CD8+ ratio (P=0.039), count of CD4+ T cells (P=0.039) and release of IFN-γ (P=0.013) and TNF-α (P=0.045) after ex-vivo T cell stimulation of whole blood were significantly higher. Furthermore, the postoperative count of basophils was significantly lower (P=0.011), HLA-DR expressing CD8- T cells were tendentially lower (P=0.058) and more suppressed (P=0.035). The suppression of IFN-γ (P=0.003) and TNF-α (P=0.006) was significantly higher in these patients after ex-vivo T cell stimulation but absolute values were similar between the groups. IL-10 release of lipopolysaccharide-stimulated whole blood was tendentially more suppressed after perioperative hyperglycemia (P=0.084).

CONCLUSIONS

Severe perioperative hyperglycemia attenuated postoperative basophil count, T cell activation and monocytic function. These patients were also at preoperative higher immune activation.

In vivo application of Granulocyte-Macrophage Colony-stimulating Factor enhances postoperative qualitative monocytic function

BACKGROUND: Granulocyte macrophage colony-stimulating factor (GM-CSF) can be used as a potent stimulator for immune suppressed patients as defined by a decrease of human leukocyte antigen-D related expression on monocytes (mHLA-DR) after surgery. However, the exact role of GM-CSF on monocytic and T cell function is unclear. METHODS: In this retrospective randomized controlled trial (RCT) subgroup analysis, monocytic respectively T cell function and T cell subspecies of 20 immune suppressed (i.e. mHLA-DR levels below 10,000 monoclonal antibodies (mAb) per cell at the first day after surgery) patients after esophageal or pancreatic resection were analyzed. Each 10 patients received either GM-CSF (250 μg/m²/d) or placebo for a maximum of three consecutive days if mHLA-DR levels remained below 10,000 mAb per cell. mHLA-DR and further parameters of immune function were measured preoperatively (od) until day 5 after surgery (pod5). Statistical analyses were performed using nonparametric statistical procedures. RESULTS: In multivariate analysis, mHLA-DR significantly differed between the groups (p < 0.001). mHLA-DR was increased on pod2 (p < 0.001) and pod3 (p = 0.002) after GM-CSF application. Tumor necrosis factor-α (TNF-α) release of lipopolysaccharide (LPS) stimulated monocytes multivariately significantly differed between the groups (p < 0.008) and was increased in the GM-CSF group on pod2 (p < 0.001) and pod3 (p = 0.046). Th17/regulatory T (Treg) cell ratio was higher after GM-CSF treatment on pod2 (p = 0.041). No differences were seen in lymphocytes and T helper cell (Th)1/Th2 specific cytokine production after T cell stimulation with Concanavalin (Con) A between the groups. CONCLUSIONS: Postoperative application of GM-CSF significantly enhanced qualitative monocytic function by increased mHLA-DR and TNF-α release after LPS stimulation and apparently enhanced Th17/Treg ratio. Clinical trial registered with www.controlled-trials.com (ISRCTN27114642) 05 December 2008.

Influence of Granulocyte-Macrophage Colony-Stimulating Factor or Influenza Vaccination on HLA-DR, Infection and Delirium Days in Immunosuppressed Surgical Patients: Double Blind, Randomised Controlled Trial

PURPOSE

Surgical patients are at high risk for developing infectious complications and postoperative delirium. Prolonged infections and delirium result in worse outcome. Granulocyte-macrophage colony-stimulating factor (GM-CSF) and influenza vaccination are known to increase HLA-DR on monocytes and improve immune reactivity. This study aimed to investigate whether GM-CSF or vaccination reverses monocyte deactivation. Secondary aims were whether it decreases infection and delirium days after esophageal or pancreatic resection over time.

METHODS

In this prospective, randomized, placebo-controlled, double-blind, double dummy trial setting on an interdisciplinary ICU of a university hospital 61 patients with immunosuppression (monocytic HLA-DR [mHLA-DR] <10,000 monoclonal antibodies [mAb] per cell) on the first day after esophageal or pancreatic resection were treated with either GM-CSF (250 μg/m2/d), influenza vaccination (Mutagrip 0.5 ml/d) or placebo for a maximum of 3 consecutive days if mHLA-DR remained below 10,000 mAb per cell. HLA-DR on monocytes was measured daily until day 5 after surgery. Infections and delirium were followed up for 9 days after surgery. Primary outcome was HLA-DR on monocytes, and secondary outcomes were duration of infection and delirium.

RESULTS

mHLA-DR was significantly increased compared to placebo (p < 0.001) and influenza vaccination (p < 0.001) on the second postoperative day. Compared with placebo, GM-CSF-treated patients revealed shorter duration of infection (p < 0.001); the duration of delirium was increased after vaccination (p = 0.003).

CONCLUSION

Treatment with GM-CSF in patients with postoperative immune suppression was safe and effective in restoring monocytic immune competence. Furthermore, therapy with GM-CSF reduced duration of infection in immune compromised patients. However, influenza vaccination increased duration of delirium after major surgery.

TRIAL REGISTRATION

www.controlled-trials.com ISRCTN27114642.

A dual-channel gas chromatography method for the quantitation of low and high concentrations of NF3 and CF4 to study membrane separation of the two compounds

A dual-channel gas chromatographic method is described in this paper that can be conveniently used for quantitation of NF3/CF4 mixtures with a thermal conductivity detector (TCD) on one channel for the quantitation of high-concentrations, and a pulsed discharge helium ionization detector (PDHID) on a second channel for the quantitation of low concentrations. It is shown that adequate separation is achieved on both channels with this dual single-column setup in which column switching as used for NF3/CF4 analysis in industrial chromatographic methods are not required, thus yielding an effective analysis method for laboratory-scale investigations. In addition, the use of packed columns with purified divinylbenzene-styrene co-polymers as the sole stationary phase yields satisfactory resolution between NF3 and CF4 at isothermal conditions of 30°C, with elution times of less than 8min on the TCD channel and less than 4min on the PDHID channel. Consequently, this method allows for reliable, straight-forward quantitation of NF3/CF4 mixtures, which is necessary when studying the commercially important problem of NF3 and CF4 separation by different methods. Therefore, the applicability of the method to studying membrane separation of NF3 and CF4 is briefly discussed and illustrated, for which the dual-channel setup is especially beneficial.

Sodium iron (III) ethylenediaminetetraacetic acid synthesis to reduce iron deficiency globally

Despite major interest in sodium iron (III) ethylenediaminetetraacetic acid's (EDTA) potential use in food fortification programs in potentially curbing the global problem of iron deficiency and its anemia, synthesis methods of stable isotope-labeled sodium iron (III) EDTA for use in human bioavailability studies are incomplete, incorrect or totally lacking. Owing to a number of clinical research groups requiring this compound in bioavailability studies, in both developing and already developed countries, we simplified and optimized the synthesis of sodium iron (III) EDTA from a block of isotopically enriched iron metal, in order that it be easily reproduced, cheaply, using simple basic laboratory apparatus. The resulting product is of high purity (>99.0%), and may be used for human stable isotope bioavailability studies. The simplicity of this method allows for the many research groups, currently doing such studies, to perform their own syntheses. Additionally, more uniformity in this synthesis will reduce the variation observed between such studies.

[The pharmacokinetics of the S35 labeled labeled garlic constituents alliin, allicin and vinyldithiine]

Three groups of 3 rats received oral doses (8 mg/kg) of garlic constituents (alliin, allicin and vinyldithiines (2-vinyl-[4H]-1,3-dithiine and 3-vinyl-[4H]-1,2-dithiine)) in the form of an oil macerate of the 35S-labeled substance. The measured activity was referred to 35S-alliin (35S-alliin equivalents). The blood activity levels in each group were monitored for 72 h. For 35S-allicin and the labeled vinyldithiines the excretion with the urine, feces, and exhaled air was also measured. The distribution among the organs (whole-body autoradiography) and the urinary metabolite pattern (thin-layer chromatography) were also determined. For 35S-alliin the blood activity profile differed considerably from those of 35S-allicin and the labeled vinyldithiines: both the absorption and the elimination of the radioactivity were distinctly faster than for the other garlic constituents, maximum blood levels being reached within the first 10 min and elimination from the blood being almost complete after 6 h. For the other garlic constituents the maximum blood levels were not reached until 30-60 min (35S-allicin) or 120 min (vinyldithiines) p.a. and blood levels > 1000 ng-Eq/ml were still present at the end of the study after 72 h. The mean total urinary and fecal excretion after 72 h was 85.5% (35S-allicin) or 92.3% (labeled vinyldithiines) of the dose. The urinary excretion indicates a minimum absorption rate of 65% (35S-allicin) or 73% (vinyldithiines). It is uncertain whether the 19-21% recovered in the feces was unabsorbed substance or had been excreted via the bile or intestinal mucosa. The exhaled air showed only traces of activity although the whole-body autoradiographs, after fairly long exposure (96 h), showed distinct enrichment of activity in the mucosa of the airways and pharynx. The activity is deposite mainly in the cartilage of the vertebral column and ribs. There was no detectable difference in organ distribution between 35S-allicin and the labeled vinyldithiines. All that could be established from the urinary metabolite pattern was that unchanged 35S-allicin and unchanged labeled vinyldithiines are absent. There is therefore extensive metabolization. The metabolites must have a very polar structure with acid functional groups since satisfactory separation was achievable only with acid solvent systems. Conjugates with sulfuric or glucuronic acid were not detectable. These results reveal no differences in pharmacokinetic behavior between 35S-allicin and the labeled vinyldithiines. A final verdict as to whether the metabolites, which may be pharmacologically active, are identical must await further studies designed to identify the metabolites.

Absorption, tissue distribution and excretion of radiolabelled compounds in rats after administration of [14C]-L-alpha-glycerylphosphorylcholine

The kinetics and metabolism of L-alpha-glycerylphosphoryl-choline (alpha-GPC) were investigated in male and female rats after i.v. (10 mg/kg) and oral doses (100-300 mg/kg). alpha-GPC was labelled with [14C]-glycerol ([14G]-GPC) or [14C]-choline ([14C]-GPC). Different kinetic and metabolic profiles were observed after i.v. and oral administration. It is assumed that alpha-GPC is hydrolyzed by phosphodiesterases in the gut mucosa. The different labelled metabolites have different kinetic properties of absorption, distribution and clearance, leading to different blood concentration-time curves of total radioactivity. Both labelled compounds gave a wide distribution of radioactivity, particularly concentrated in the liver, kidney, lung and spleen compared to blood. Brain concentrations of [14C]-GPC were comparable to ([14G]-GPC) or lower than ([14C]-GPC) total blood radioactivity. The metabolite profile in the perfused brain showed a small amount of choline and two unknown metabolites, probably the same as in blood. In addition, choline was incorporated into brain phospholipids in increasing amounts within 24 h of dosing. In all cases renal and fecal excretion of radioactivity was low and comparable for [14G]-GPC and [14C]-GPC. Mostly the administered radioactivity was exhaled as 14CO2, this degradation being faster and more pronounced for the glycerol-labelled metabolites than for the choline-labelled metabolites for both routes of administration. In all cases the results were the same for male and female rats.

[Methodical studies of transmucosal oxygen partial pressure measurement in the calf and dog]

Transcutaneous PO2-measurement has been thought being non practicable in veterinary medicine. Consequently, the measuring method has been slightly modified. PO2 was taken from the mucous membrane of the lower surface of tongue. This has been practised in 6 dogs and 10 calves. We achieved a significant correlation between transmucosal and arterial PO2, taken simultaneously in each animal. Considering these results the use of transmucosal measurement may be recommended for a trend-measuring in anesthesized animals. Nevertheless, there has to be pointed out that transmucosal PO2 has to be interpreted regarding its complexity.

Pharmacokinetics and metabolism of 14C-oxaceprol in beagle dogs after intramuscular and oral administration

Blood and plasma levels and renal and faecal excretion of 14C-oxaceprol (N-acetyl-4-hydroxyproline, AHP 200) were measured after p.o. and after i.m. administration to 3 male Beagle dogs each. In addition, the concentration of 14C-oxaceprol equivalents in synovia was determined at tmax and at tmax + t1/2(elim.). The pattern of metabolites was investigated for plasma, synovia, and urine samples. Peak plasma levels were obtained for the individual animals between 20 and 30 min after i.m. administration and between 2 and 2.5 h after p.o. administration, respectively. The concentrations of 14C-oxaceprol equivalents in synovia 2.5 and 3.5 h after oral administration and 1.3 h after i.m. administration were comparable to the respective plasma levels at the same time. After oral administration the amount of absorbed oxaceprol varied between 43 and 79% of the dose. Oxaceprol was exclusively eliminated via the kidneys. Excretion was complete within 72 h p.a. for both administration routes. Elimination half-lives were 44 +/- 9 min. or 68 +/- 14 min. (means +/- S.D.) after i.m. and p.o. administration, respectively. Oxaceprol was not metabolized.

High-performance liquid chromatographic determination of ibuprofen, its metabolites and enantiomers in biological fluids

An isocratic high-performance liquid chromatographic method to determine racemic ibuprofen (assay I) and its major metabolites (assay II) in biological fluids (plasma, urine, bile) using a conventional reversed-phase column is described. A third assay using beta-cyclodextrin as stationary phase (Cyclobond I) for the separation of the ibuprofen enantiomers is also described. A wavelength of 220 nm was used to monitor the substances. The sensitivity of the method was 0.1 microgram/ml for all three assays. The method was demonstrated to be suitable for stereoselective pharmacokinetic studies of ibuprofen in humans and animals.

[The fat mobilization syndrome in guinea pigs (Cavia porcellus L.)]

Feeding experiments were applied to 82 guinea pigs, different by age, sex, and stage of reproduction, and showed that high-energy feeding and subsequent feed withdrawal could trigger off with high probability a fat mobilising syndrome with clinically manifest ketosis in animals in gravidity and lactation or subclinical ketosis in all non-gravid individuals. High-energy or restrictive feeding alone did not cause in guinea pigs any disease along the lines of gravidity toxicosis. Aspects relating to aetiological and pathogenetic comparability with ruminants are discussed in some detail.

[The acid-base status of venous blood and erythrocyte hemolysate in the dog]

Determination of intracellular acid-base status is reported in this paper by the example of erythrocytic haemolysate in dog. The difference between intracellular and extracellular acid-base ratios is highly significant and is of clinical relevance. Differences between species and the need for further experimental verification of the method are discussed in some detail. Reference values are suggested for orientation, on the basis of 20 experimental dogs.

[Comparative studies of the acid-base status in venous, capillary and mixed blood from the ear of the dog]

Ten experimental dogs were tested in twelve experimental arrangements, with a view to finding out the extent to which results of acid-base determination or blood gas analysis could be significantly affected by induced hyperaemia of the ear or by the choice of a site for blood collection, including puncture of an ear vein. No difference was secured. Hence, ear vein puncture may be used to collect so-called capillary blood. Reference is made to the author's own values for use as criteria.

Temperature-dependent structural rearrangement of apotryptophanase in potassium phosphate

Apotryptophanase (L-tryptophan indole-lyase, EC 4.1.99.1) from Escherichia coli B/1t7A shows, in the presence of potassium phosphate, a temperature-dependent structural rearrangement which is not observed in the presence of sodium phosphate or imidazole plus KC1. This rearrangement can be described by a two-state equilibrium between two forms of the apoenzyme. The midpoint temperature of the rearrangement (TM) and the van't Hoff enthalpy (delta H) at different potassium phosphate concentrations and pH values, respectively, were determined by measuring the temperature-dependence of the ultraviolet absorbance of apotryptophanase. Increasing the potassium phosphate concentration at pH 7.8 causes a simultaneous increase in total absorbance and the delta H value, whereas the TM increases between pH 7.0 and 7.8 but starts to decrease at pH values above 7.8. In 0.1 M potassium phosphate at the pH optimum of the enzyme (7.8) TM and delta H were found to be 293.1 K and 167 kJ X mol-1, respectively. Moreover, the tyrosine residues of apotryptophanase dissociate in potassium phosphate and in imidazole plus KCl with pK values of 8.6 and 9.8, respectively, indicating that potassium phosphate favors the formation of tyrosinate. The rearrangement might be interpreted as the formation of specific hydrogen bonds between tyrosine and potassium phosphate which are ruptured at higher temperature. Such hydrogen bonds cannot be formed at all or only to a small extent in the presence of imidazole plus KCl or sodium phosphate. Those hydrogen bonds stabilize the structure of apotryptophanase. In contrast, holotryptophanase requires only K+ for enzymatic activity.