Relationship between positive end-expiratory pressure levels, central venous pressure, systemic inflammation and acute renal failure in critically ill ventilated COVID-19 patients: a monocenter retrospective study in France.

BACKGROUND: The role of positive pressure ventilation, central venous pressure (CVP) and inflammation on the occurrence of acute kidney injury (AKI) have been poorly described in mechanically ventilated patient secondary to coronavirus disease 2019 (COVID-19). METHODS: This was a monocenter retrospective cohort study of consecutive ventilated COVID-19 patients admitted in a French surgical intensive care unit between March 2020 and July 2020. Worsening renal function (WRF) was defined as development of a new AKI or a persistent AKI during the 5 days after mechanical ventilation initiation. We studied the association between WRF and ventilatory parameters including positive end-expiratory pressure (PEEP), CVP, and leukocytes count. RESULTS: Fifty-seven patients were included, 12 (21%) presented WRF. Daily PEEP, 5 days mean PEEP and daily CVP values were not associated with occurrence of WRF. 5 days mean CVP was higher in the WRF group compared to patients without WRF (median [IQR], 12 mm Hg [11-13] vs. 10 mm Hg [9-12]; P=0.03). Multivariate models with adjustment on leukocytes and Simplified Acute Physiology Score (SAPS) II confirmed the association between CVP value and risk of WRF (odd ratio, 1.97; 95% confidence interval, 1.12-4.33). Leukocytes count was also associated with occurrence of WRF in the WRF group (14 G/L [11-18]) and the no-WRF group (9 G/L [8-11]) (P=0.002). CONCLUSIONS: In mechanically ventilated COVID-19 patients, PEEP levels did not appear to influence occurrence of WRF. High CVP levels and leukocytes count are associated with risk of WRF.

Influence of systemic hemodynamics on microcirculation during sepsis.

PURPOSE: During sepsis, improvement of hemodynamic may not be related to improvement of microcirculation. The aim of this study was to investigate influence of systemic circulation on microcirculation in septic ICU patients. METHODS: This is a prospective cohort study of septic ICU patients. Microcirculation was investigated with Near infrared spectrometry (NIRS) measuring tissue oxygen saturation (StO2). StO2 desaturation (desStO2) and resaturation (resStO2) slopes were determined. Analyses were made at baseline and after fluid challenges. RESULTS: Seventy-two patients were included. One hundred and sixty measures were performed at baseline. StO2 was 77.8% [72.4-85.0] and resStO2 was 87.3%/min [57.8-141.7]. Univariate analysis showed an association between resStO2 and diastolic arterial pressure (DAP) (p = .001), and norepinephrine dose (p = .033). In multivariate linear regression, there was an association between resStO2 and DAP (ß = 1.85 (0.64 to 3.08), p = .004). Fluid challenges (n = 60) increased CO, and resStO2 (all p < .001). In multivariate analysis, variation of stroke volume was associated with variation of resStO2 (p = .004) after fluid challenge. There was no association between CVP and resStO2. CONCLUSIONS: DAP was the only independent determinant of resStO2 in septic patients. Fluid challenges may improve microcirculation. CVP did not influence resStO2.

Reactive oxygen species measure for rapid detection of infection in fluids.

BACKGROUND: Early detection of infection is critical to rapidly starting effective treatment. Diagnosis can be difficult, particularly in the intensive care unit (ICU) population. Because the presence of polymorphonuclear neutrophils in tissues is the hallmark of inflammatory processes, the objective of this proof of concept study was to determine whether the measurement of reactive oxygen species (ROS) could be an efficient diagnostic tool to rapidly diagnose infections in peritoneal, pleural and bronchoalveolar lavage (BAL) fluids in ICU patients. METHODS: We prospectively included all patients hospitalized in the 21-bed surgical ICU of a teaching hospital from June 2010 to February 2014 who presented with systemic inflammatory response syndrome with suspicion of a peritoneal or pleural fluid or pulmonary infection needing a BAL. Instantaneous basal ROS production was measured in fluids and after phorbol 12-myristate 13-acetate (PMA) stimulation. We compared patients with infected fluids to those with non-infected fluids. RESULTS: The overall ICU mortality rate was 34 %. A majority of patients were sampled following a delay of 5 days (2-12) after ICU admission, with most receiving antibiotics at the time of fluid sampling (71 %). Fluids were infected in 21/65 samples: 6/17 peritoneal fluids, 8/28 pleural fluids and 7/20 BALs. ROS production was significantly higher in the infected than in the non-infected group at baseline and after PMA stimulation in the peritoneal and pleural fluids but not in BAL. CONCLUSION: Assessing instantaneous ROS production appears as a fast and reliable diagnostic method for detecting peritoneal and pleural fluid infection.