P05.01.B Distribution of the staining agent sodium-fluorescein in cerebral neoplasia - a comparison between intraoperative confocal laser endomicroscopy and in vitro fluorescence microscopy

Background

While conventional frozen sections and other ex vivo microscopy always come along with artefacts, in vivo confocal laser endomicroscopy (CLE) offers less invasive, less manipulated imaging of living tissues. Understanding the distribution of the staining agent sodium-fluorescein (NaFl) plays a key role in establishing in vivo CLE as a new opportunity for real-time transmitted, in vivo imaging.

By comparing the distribution of NaFl in in vivo and ex vivo CLE to conventional fluorescence microscopy of NaFl incubated tumor cell cultures we gain a better understanding of the staining mechanism.

Material and Methods

Sodium-fluorescein is the water-soluble sodium salt of fluorescein and is used as a fluorescent tracer in neurosurgery. The staining agent was applied intravenously at the beginning of the surgical procedure. In vivo CLE of the lesion was performed 30 to 50 minutes later and compared to ex vivo CLE imaging and conventional fluorescence microscopy. In addition, different tumor cell lines derived from malignant gliomas and carcinomas, respectively, were incubated with NaFl in vitro and the uptake of the fluorescent dye was monitored over time.

Results

From initial results, the intraoperative images showed specific fluorescein distribution depending on the architecture of the tumor entity. In most cases, glial tumors demonstrated higher accumulation of the staining agent in the extracellular tumor matrix, whereas the cells of carcinoma metastases appeared to take up NaFl intracellularly. These results were corroborated by NaFl uptake in cell culture experiments.

Compared to ex vivo CLE, in vivo imaging offered a faster assessment of the tissue, brighter images and higher staining levels. Due to movement artefacts and the narrow intraoperative imaging time frame, in vivo CLE images were sometimes impaired by lower image quality.

Conclusion

The specific distribution of the fluorescent agent NaFl allowed for a discrimination between the different neoplastic entities. Images from in vivo and ex vivo confocal laser endomicroscopy showed NaFl uptake in concordance with the results of NaFl incubated cell cultures.

Intraoperative, in vivo confocal laser endomicroscopy shows promising first results in the understanding of brain tumor histomorphology in situ. Being faster and less manipulated by artefacts than ex vivo investigations, it opens up wider opportunities for research and intraoperative diagnostics.

Epidural analgesia in ICU chest trauma patients with fractured ribs: retrospective study of pain control and intubation requirements

BACKGROUND

Nonintubated chest trauma patients with fractured ribs admitted to the intensive care unit (ICU) are at risk for complications and may require invasive ventilation at some point. Effective pain control is essential. We assessed whether epidural analgesia (EA) in patients with fractured ribs who were not intubated at ICU admission decreased the need for invasive mechanical ventilation (IMV). We also looked for risk factors for IMV.

STUDY DESIGN AND METHODS

This retrospective, observational, multicenter study conducted in 40 ICUs in France included consecutive patients with three or more fractured ribs who were not intubated at admission between July 2013 and July 2015.

RESULTS

Of the 974 study patients, 788 were included in the analysis of intubation predictors. EA was used in 130 (16.5%) patients, and 65 (8.2%) patients required IMV. Factors independently associated with IMV were chronic respiratory disease (P = 0.008), worse SAPS II (P < 0.0001), flail chest (P = 0.02), worse Injury Severity Score (P = 0.0003), higher respiratory rate at admission (P = 0.02), alcohol withdrawal syndrome (P < 0.001), and noninvasive ventilation (P = 0.04). EA was not associated with decreases in IMV requirements, median numerical rating scale pain score, or intravenous morphine requirements from day 1 to day 7.

CONCLUSIONS

EA was not associated with a lower risk of IMV in chest trauma patients with at least 3 fractured ribs, moderate pain, and no intubation on admission. Further studies are needed to clarify the optimal pain control strategy in chest trauma patients admitted to the ICU, notably those with severe pain or high opioid requirements.

Compared effects of inhibition and exogenous administration of hydrogen sulphide in ischaemia-reperfusion injury

Introduction

Haemorrhagic shock is associated with an inflammatory response consecutive to ischaemia-reperfusion (I/R) that leads to cardiovascular failure and organ injury. The role of and the timing of administration of hydrogen sulphide (H₂S) remain uncertain. Vascular effects of H₂S are mainly mediated through K⁺_ATP-channel activation. Herein, we compared the effects of D,L-propargylglycine (PAG), an inhibitor of H₂S production, as well as sodium hydrosulphide (NaHS), an H₂S donor, on haemodynamics, vascular reactivity and cellular pathways in a rat model of I/R. We also compared the haemodynamic effects of NaHS administered before and 10 minutes after reperfusion.

Methods

Mechanically ventilated and instrumented rats were bled during 60 minutes in order to maintain mean arterial pressure at 40 ± 2 mmHg. Ten minutes prior to retransfusion, rats randomly received either an intravenous bolus of NaHS (0.2 mg/kg) or vehicle (0.9% NaCl) or PAG (50 mg/kg). PNU, a pore-forming receptor inhibitor of K⁺_ATP channels, was used to assess the role of K⁺_ATP channels.

Results

Shock and I/R induced a decrease in mean arterial pressure, lactic acidosis and ex vivo vascular hyporeactivity, which were attenuated by NaHS administered before reperfusion and PNU but not by PAG and NaHS administered 10 minutes after reperfusion. NaHS also prevented aortic inducible nitric oxide synthase expression and nitric oxide production while increasing Akt and endothelial nitric oxide synthase phosphorylation. NaHS reduced JNK activity and p-P38/P38 activation, suggesting a decrease in endothelial cell activation without variation in ERK phosphorylation. PNU + NaHS increased mean arterial pressure when compared with NaHS or PNU alone, suggesting a dual effect of NaHS on vascular reactivity.

Conclusion

NaHS when given before reperfusion protects against the effects of haemorrhage-induced I/R by acting primarily through a decrease in both proinflammatory cytokines and inducible nitric oxide synthase expression and an upregulation of the Akt/endothelial nitric oxide synthase pathway.

Keywords: hydrogen sulphide, inflammation mediators, therapeutic use, shock, hemorrhagic/drug therapy, haemodynamics/drug effects

The epidemiology of septic shock in French intensive care units: the prospective multicenter cohort EPISS study

INTRODUCTION

To provide up-to-date information on the prognostic factors associated with 28-day mortality in a cohort of septic shock patients in intensive care units (ICUs).

METHODS

Prospective, multicenter, observational cohort study in ICUs from 14 French general (non-academic) and university teaching hospitals. All consecutive patients with septic shock admitted between November 2009 and March 2011 were eligible for inclusion. We prospectively recorded data regarding patient characteristics, infection, severity of illness, life support therapy, and discharge.

RESULTS

Among 10,941 patients admitted to participating ICUs between October 2009 and September 2011, 1,495 (13.7%) patients presented inclusion criteria for septic shock and were included. Invasive mechanical ventilation was needed in 83.9% (n=1248), inotropes in 27.7% (n=412), continuous renal replacement therapy in 32.5% (n=484), and hemodialysis in 19.6% (n=291). Mortality at 28 days was 42% (n=625). Variables associated with time to mortality, right-censored at day 28: age (for each additional 10 years) (hazard ratio (HR)=1.29; 95% confidence interval (CI): 1.20-1.38), immunosuppression (HR=1.63; 95%CI: 1.37-1.96), Knaus class C/D score versus class A/B score (HR=1.36; 95%CI:1.14-1.62) and Sepsis-related Organ Failure Assessment (SOFA) score (HR=1.24 for each additional point; 95%CI: 1.21-1.27). Patients with septic shock and renal/urinary tract infection had a significantly longer time to mortality (HR=0.56; 95%CI: 0.42-0.75).

CONCLUSION

Our observational data of consecutive patients from real-life practice confirm that septic shock is common and carries high mortality in general ICU populations. Our results are in contrast with the clinical trial setting, and could be useful for healthcare planning and clinical study design.

[Arsenic poisoning: a special gastroenteritis...]

Arsenic (As) intoxication is nowadays extremely rare. Two cases of acute and chronic As criminal poisoning leading to death of a couple of retired people, are reported. Clinical presentation was simulating a gastro-enteritidis with fast evolution to refractory shock. Toxicological analysis confirmed this diagnostic, with respectively blood As concentrations at 579 and 21 765 microg/l for our two patients.