Dataset Information

CO2 and O2 removal during continuous veno-venous hemofiltration: a pilot study.

ABSTRACT: BACKGROUND:Carbon dioxide (CO2) accumulation is a challenging issue in critically ill patients. CO2 can be eliminated by renal replacement therapy but studies are scarce and clinical relevance is unknown. We prospectively studied CO2 and O2 behavior at different sample points of continuous veno-venous hemofiltration (CVVH) and build a model to calculate CO2 removal bedside. METHODS:In 10 patients receiving standard CVVH under citrate anticoagulation, blood gas analysis was performed at different sample points within the CVVH circuit. Citrate was then replaced by NaCl 0.9% and sampling was repeated. Total CO2 (tCO2), CO2 flow (V?CO2) and O2 flow (V?O2) were compared between different sample points. The effect of citrate on transmembrane tCO2 was evaluated. Wilcoxon matched-pairs signed rank test was performed to evaluate significance of difference between 2 data sets. Friedman test was used when more data sets were compared. RESULTS:V?CO2 in the effluent (26.0?ml/min) correlated significantly with transmembrane V?CO2 (24.2?ml/min). This represents 14% of the average expired V?CO2 in ventilated patients. Only 1.3?ml/min CO2 was removed in the de-aeration chamber, suggesting that CO2 was almost entirely cleared across the membrane filter. tCO2 values in effluent, before, and after the filter were not statistically different. Transmembrane tCO2 under citrate or NaCl 0.9% predilution also did not differ significantly. No changes in V?O2 were observed throughout the CVVH circuit. Based on recorded data, formulas were constructed that allow bedside evaluation of CVVH-attributable CO2 removal. CONCLUSION:A relevant amount of CO2 is removed by CVVH and can be quantified by one simple blood gas analysis within the circuit. Future studies should assess the clinical impact of this observation. TRIAL REGISTRATION:The trial was registered at https://clinicaltrials.gov with trial registration number NCT03314363 on October 192,017.

SUBMITTER: Jonckheer J

PROVIDER: S-EPMC6580471 | biostudies-literature | 2019 Jun

REPOSITORIES: biostudies-literature

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CO<sub>2</sub> and O<sub>2</sub> removal during continuous veno-venous hemofiltration: a pilot study.

Jonckheer Joop J Spapen Herbert H Debain Aziz A Demol Joy J Diltoer Marc M Costa Olivier O Lanckmans Katrien K Oshima Taku T Honoré Patrick M PM Malbrain Manu M De Waele Elisabeth E

BMC nephrology 20190617 1

<h4>Background</h4>Carbon dioxide (CO<sub>2</sub>) accumulation is a challenging issue in critically ill patients. CO<sub>2</sub> can be eliminated by renal replacement therapy but studies are scarce and clinical relevance is unknown. We prospectively studied CO<sub>2</sub> and O<sub>2</sub> behavior at different sample points of continuous veno-venous hemofiltration (CVVH) and build a model to calculate CO<sub>2</sub> removal bedside.<h4>Methods</h4>In 10 patients receiving standard CVVH under ...[more]

PMID: 31208356

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Project description:BackgroundMetabolic alkalosis is a frequently occurring problem during continuous veno-venous hemofiltration (CVVH) with regional citrate anticoagulation (RCA). This study aimed to evaluate the effectiveness of switching from high to low bicarbonate (HCO3-) replacement fluid in alkalotic critically ill patients with acute kidney injury treated by CVVH and RCA.MethodsA retrospective-comparative study design was applied. Patients who underwent CVVH with RCA in the ICU between 09/2016 and 11/2017 were evaluated. Data were available from the clinical routine. A switch of the replacement fluid Phoxilium® (30 mmol/l HCO3-) to Biphozyl® (22 mmol/l HCO3-) was performed as blood HCO3- concentration persisted ≥ 26 mmol/l despite adjustments of citrate dose and blood flow. Data were collected from 72 h before the switch of the replacement solutions until 72 h afterwards.ResultsOf 153 patients treated with CVVH during that period, 45 patients were switched from Phoxilium® to Biphozyl®. Forty-two patients (42 circuits) were available for statistical analysis. After switching the replacement fluid from Phoxilium® to Biphozyl® the serum HCO3- concentration decreased significantly from 27.7 mmol/l (IQR 26.9-28.9) to 25.8 mmol/l (IQR 24.6-27.7) within 24 h (p < 0.001). Base excess (BE) decreased significantly from 4.0 mmol/l (IQR 3.1-5.1) to 1.8 mmol/l (IQR 0.2-3.4) within 24 h (p < 0.001). HCO3- and BE concentration remained stable from 24 h till the end of observation at 72 h after the replacement fluid change (p = 0.225). pH and PaCO2 did not change significantly after the switch of the replacement fluid until 72 h.ConclusionsThis retrospective analysis suggests that for patients developing refractory metabolic alkalosis during CVVH with RCA the use of Biphozyl® reduces external HCO3- load and sustainably corrects intracorporeal HCO3- and BE concentrations. Future studies have to prove whether correcting metabolic alkalosis during CVVH with RCA in critically ill patients is of relevance in terms of clinical outcome.

Project description:BackgroundContinuous veno-venous hemofiltration (CVVH) can be used to reduce fluid overload and tissue edema, but excessive fluid removal may impair tissue perfusion. Skin blood flow (SBF) alters rapidly in shock, so its measurement may be useful to help monitor tissue perfusion.MethodsIn a prospective, observational study in a 35-bed department of intensive care, all patients with shock who required fluid removal with CVVH were considered for inclusion. SBF was measured on the index finger using skin laser Doppler (Periflux 5000, Perimed, Järfälla, Sweden) for 3 min at baseline (before starting fluid removal, T0), and 1, 3 and 6 h after starting fluid removal. The same fluid removal rate was maintained throughout the study period. Patients were grouped according to absence (Group A) or presence (Group B) of altered tissue perfusion, defined as a 10% increase in blood lactate from T0 to T6 with the T6 lactate ≥ 1.5 mmol/l. Receiver operating characteristic curves were constructed and areas under the curve (AUROC) calculated to identify variables predictive of altered tissue perfusion. Data are reported as medians [25th-75th percentiles].ResultsWe studied 42 patients (31 septic shock, 11 cardiogenic shock); median SOFA score at inclusion was 9 [8-12]. At T0, there were no significant differences in hemodynamic variables, norepinephrine dose, lactate concentration, ScvO2 or ultrafiltration rate between groups A and B. Cardiac index and MAP did not change over time, but SBF decreased in both groups (p < 0.05) throughout the study period. The baseline SBF was lower (58[35-118] vs 119[57-178] perfusion units [PU], p = 0.03) and the decrease in SBF from T0 to T1 (ΔSBF%) higher (53[39-63] vs 21[12-24]%, p = 0.01) in group B than in group A. Baseline SBF and ΔSBF% predicted altered tissue perfusion with AUROCs of 0.83 and 0.96, respectively, with cut-offs for SBF of ≤ 57 PU (sensitivity 78%, specificity 87%) and ∆SBF% of ≥ 45% (sensitivity 92%, specificity 99%).ConclusionBaseline SBF and its early reduction after initiation of fluid removal using CVVH can predict worsened tissue perfusion, reflected by an increase in blood lactate levels.

Project description:BackgroundMyoglobin clearance in acute kidney injury requiring renal replacement therapy is important because myoglobin has direct renal toxic effects. Clinical data comparing different modalities of renal replacement therapy addressing myoglobin clearance are limited. This study aimed to compare two renal replacement modalities regarding myoglobin clearance.MethodsIn this prospective, randomized, single-blinded, single-center trial, 70 critically ill patients requiring renal replacement therapy were randomized 1:1 into an intervention arm using continuous veno-venous hemodialysis with high cutoff dialyzer and a control arm using continuous veno-venous hemodiafiltration postdilution with high-flux dialyzer. Regional citrate anticoagulation was used in both groups to maintain the extracorporeal circuit. The concentrations of myoglobin, urea, creatinine, β2-microglobulin, interleukin-6 and albumin were measured before and after the dialyzer at 1 h, 6 h, 12 h, 24 h and 48 h after initiating continuous renal replacement therapy.ResultsThirty-three patients were allocated to the control arm (CVVHDF with high-flux dialyzer) and 35 patients to the intervention arm (CVVHD with high cutoff dialyzer). Myoglobin clearance, as a primary endpoint, was significantly better in the intervention arm than in the control arm throughout the whole study period. The clearance values for urea and creatinine were higher in the control arm. There was no measurable albumin clearance in both arms. The clearance data for β2-microglobulin and interleukin-6 were non-inferior in the intervention arm compared to those for the control arm. Dialyzer lifespan was 57.0 [38.0, 72.0] hours in the control arm and 70.0 [56.75, 72.0] hours in the intervention arm (p = 0.029).ConclusionsMyoglobin clearance using continuous veno-venous hemodialysis with high cutoff dialyzer and regional citrate anticoagulation is better than that with continuous veno-venous hemodiafiltration with regional citrate anticoagulation.Trial registrationGerman Clinical Trials Registry (DRKS00012407); date of registration 23/05/2017. https://www.drks.de/drks_web/navigate.do?navigationId=trial.HTML&TRIAL_ID=DRKS00012407 .

Project description:Background: We investigated the association of damage-associated molecular pattern (DAMP) removal with mortality in sepsis patients undergoing continuous veno-venous hemofiltration (CVVH). Methods: Circulating levels of DAMPs [mitochondrial DNA (mtDNA); nuclear DNA (nDNA); heat shock protein 70 (HSP70); and high mobility group box 1 (HMGB1)] and cytokines were measured at baseline, 6 and 12 h after initiation of CVVH. Urinary DNA levels were analyzed at baseline and end of CVVH. The expression of human leukocyte antigen (HLA)-DR was assayed at 0, 3, and 7 days after initiation of CVVH. Moreover, the effects of HSP70 and HMGB1 clearance on survival were analyzed. Results: We evaluated 43 patients with acute kidney injury (AKI) (33 sepsis patients). Twenty-two sepsis patients (67%) and three non-sepsis patients (30%) expired (P = 0.046). Significant reductions in the levels of circulating interleukin-6 (P = 0.046) and tumor necrosis factor-? (P = 0.008) were found in the sepsis group. The levels of mtDNA were increased (ND2, P = 0.035; D-loop, P = 0.003), whereas that of HSP70 was reduced (P = 0.000) in all patients during the first 12 h. The levels of DAMPs in the plasma were markedly increased after blood passage from the inlet through the dialyzer in survivor sepsis patients. The clearance rates of HSP70 and HMGB1 were good predictors of mortality [area under the curve (AUC) = 0.937, P = 0.000; AUC = 0.90, P = 0.001, respectively]. The level of HLA-DR was increased in response to higher HSP70 clearance (P = 0.006). Survival was significantly worse in groups with higher clearance rates of HSP70 and HMGB1 than the cut-off value (log-rank test: P = 0.000 for both). Higher HSP70 clearance was a significant independent predictor of mortality (odds ratio = 1.025, 95% confidence interval [CI]: 1.012-1.039, P = 0.000). The urinary nDNA (?-globin) level before CVVH was an independent risk factor for the duration of CVVH in patients with sepsis (sRE = 0.460, 95% CI: 1.720-8.857, P = 0.005). Conclusion: CVVH removes inflammatory factors, reduces urinary DAMPs, and removes plasma DAMPs. However, survival decreases in response to higher HSP70 clearance.

Dataset Information

CO2 and O2 removal during continuous veno-venous hemofiltration: a pilot study.

Publications

CO<sub>2</sub> and O<sub>2</sub> removal during continuous veno-venous hemofiltration: a pilot study.

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