Standard vs. carbone dioxide adapted kidney replacement therapy in hypercapnic ARDS patients: a randomized controlled pilot trial (BigBIC).

BACKGROUND: Current continuous kidney replacement therapy (CKRT) protocols ignore physiological renal compensation for hypercapnia. This study aimed to explore feasibility, safety, and clinical benefits of pCO2-adapted CKRT for hypercapnic acute respiratory distress syndrome (ARDS) patients with indication for CKRT. METHODS: We enrolled mechanically ventilated hypercapnic ARDS patients (pCO2 > 7.33 kPa) receiving regional citrate anticoagulation (RCA) based CKRT in a prospective, randomized-controlled pilot-study across five intensive care units at the Charité-Universitätsmedizin Berlin, Germany. Patients were randomly assigned 1:1 to the control group with bicarbonate targeted to 24 mmol/l or pCO2-adapted-CKRT with target bicarbonate corresponding to physiological renal compensation. Study duration was six days. Primary outcome was bicarbonate after 72 h. Secondary endpoints included safety and clinical endpoints. Endpoints were assessed in all patients receiving treatment. RESULTS: From September 2021 to May 2023 40 patients (80% male) were enrolled. 19 patients were randomized to the control group, 21 patients were randomized to pCO2-adapted-CKRT. Five patients were excluded before receiving treatment: three in the control group (consent withdrawal, lack of inclusion criteria fulfillment (n = 2)) and two in the intervention group (lack of inclusion criteria fulfillment, sudden unexpected death) and were therefore not included in the analysis. Median plasma bicarbonate 72 h after randomization was significantly higher in the intervention group (30.70 mmol/l (IQR 29.48; 31.93)) than in the control group (26.40 mmol/l (IQR 25.63; 26.88); p < 0.0001). More patients in the intervention group received lung protective ventilation defined as tidal volume < 8 ml/kg predicted body weight. Thirty-day mortality was 10/16 (63%) in the control group vs. 8/19 (42%) in the intervention group (p = 0.26). CONCLUSION: Tailoring CKRT to physiological renal compensation of respiratory acidosis appears feasible and safe with the potential to improve patient care in hypercapnic ARDS. TRIAL REGISTRATION: The trial was registered in the German Clinical Trials Register (DRKS00026177) on September 9, 2021 and is now closed.

Impact of AKI on metabolic compensation for respiratory acidosis in ICU patients with AECOPD.

PURPOSE: Acute exacerbation of chronic obstructive pulmonary disease (AECOPD) can result in severe respiratory acidosis. Metabolic compensation is primarily achieved by renal retention of bicarbonate. The extent to which acute kidney injury (AKI) impairs the kidney's capacity to compensate for respiratory acidosis remains unclear. MATERIALS AND METHODS: This retrospective analysis covers clinical data between January 2009 and December 2021 for 498 ICU patients with AECOPD and need for respiratory support. RESULTS: 278 patients (55.8%) presented with or developed AKI. Patients with AKI exhibited higher 30-day-mortality rates (14.5% vs. 4.5% p = 0.001), longer duration of mechanical ventilation (median 90 h vs. 14 h; p = 0.001) and more severe hypercapnic acidosis (pH 7.23 vs. 7.28; pCO2 68.5 mmHg vs. 61.8 mmHg). Patients with higher AKI stages exhibited lower HCO3-/pCO2 ratios and did not reach expected HCO3- levels. In a mixed model analysis with random intercept per patient we analyzed the association of pCO2 (independent) and HCO3- (dependent variable). Lower estimates for averaged change in HCO3- were observed in patients with more severe AKI. CONCLUSION: AKI leads to poor outcomes and compromises metabolic compensation of respiratory acidosis in ICU patients with AECOPD. While buffering agents may aid compensation for severe AKI, their use should be approached with caution.

Is the routine use of antipseudomonal antibiotics in acutely exacerbated COPD patients indicated: A retrospective analysis in 437 ICU patients.

PURPOSE: Chronic obstructive pulmonary disease (COPD) is a risk factor for acquiring multiple drug resistant bacteria. The main objective of this analysis was to question a beneficial outcome in the routine use of antipseudomonal antibiotics in the empiric treatment of severe AECOPD in Intensive Care Unit patients. MATERIAL AND METHODS: We report a retrospective, observational cohort study in adult patients with severe AECOPD admitted to ICU at a tertiary care university hospital. Antibiotic treatment on admission as well as microbiology samples were analyzed. The influence of SOFA score at admission, age, sex and antibiotic choice upon survival was investigated by multivariable analysis. RESULTS: 437 patients were included. Mean age was 68 years (±10), 46.5% were female. 271/437 patients (62%) were initially treated with antibiotics covering Pseudomonas aeruginosa. Overall, positive microbiology samples were found in 107 patients (24.5%). P. aeruginosa was only found in 3.7%. There was no significant difference in 30-day ICU mortality after adjusting for age, sex and severity of illness (20.4% ± 11.6 in patients with Pseudomonas inactive antibiotics versus 29.3% ± 10.8 in patients with PAA, p=0.113). CONCLUSIONS: Empiric use of antipseudomonal antibiotics did not result in improved ICU survival in this retrospective analysis.