High flow nasal oxygen therapy to avoid invasive mechanical ventilation in SARS-CoV-2 pneumonia: a retrospective study.

BACKGROUND: The efficacy of high flow nasal canula oxygen therapy (HFNO) to prevent invasive mechanical ventilation (IMV) is not well established in severe coronavirus disease 2019 (COVID-19). The aim of this study was to compare the risk of IMV between two strategies of oxygenation (conventional oxygenation and HFNO) in critically ill COVID 19 patients. METHODS: This was a bicenter retrospective study which took place in two intensive care units (ICU) of tertiary hospitals in the Paris region from March 11, to May 3, 2020. We enrolled consecutive patients hospitalized for COVID-19 and acute respiratory failure (ARF) who did not receive IMV at ICU admission. The primary outcome was the rate of IMV after ICU admission. Secondary outcomes were death at day 28 and day 60, length of ICU stay and ventilator-free days at day 28. Data from the HFNO group were compared with those from the standard oxygen therapy (SOT) group using weighted propensity score. RESULTS: Among 138 patients who met the inclusion criteria, 62 (45%) were treated with SOT alone, and 76 (55%) with HFNO. In HFNO group, 39/76 (51%) patients received IMV and 46/62 (74%) in SOT group (OR 0.37 [95% CI, 0.18-0.76] p = 0.007). After weighted propensity score, HFNO was still associated with a lower rate of IMV (OR 0.31 [95% CI, 0.14-0.66] p = 0.002). Length of ICU stay and mortality at day 28 and day 60 did not significantly differ between HFNO and SOT groups after weighted propensity score. Ventilator-free days at days 28 was higher in HNFO group (21 days vs 10 days, p = 0.005). In the HFNO group, predictive factors associated with IMV were SAPS2 score (OR 1.13 [95%CI, 1.06-1.20] p = 0.0002) and ROX index > 4.88 (OR 0.23 [95%CI, 0.008-0.64] p = 0.006). CONCLUSIONS: High flow nasal canula oxygen for ARF due to COVID-19 is associated with a lower rate of invasive mechanical ventilation.

Diafiltration flowrate is a determinant of the extent of adsorption of amikacin in renal replacement therapy using the ST150®-AN69 filter: An in vitro study.

INTRODUCTION: In continuous renal replacement therapy, conduction and convection are controlled allowing prescribing dosage regimen improving survival. In contrast, adsorption is an uncontrolled property altering drug disposition. Whether adsorption depends on flowrates is unknown. We hypothesized an in vitro model may provide information in conditions mimicking continuous renal replacement therapy in humans. METHODS: ST150®-AN69 filter and Prismaflex dialyzer, Baxter-Gambro were used. Simulated blood flowrate was set at 200 mL/min. The flowrates in the filtration (continuous filtration), dialysis (continuous dialysis), and diafiltration (continuous diafiltration) were 1500, 2500, and 4000 mL/h, respectively. Routes of elimination were assessed using NeckEpur® analysis. RESULTS: The percentages of the total amount eliminated by continuous filtration, continuous dialysis, and continuous diafiltration were 82%, 86%, and 94%, respectively. Elimination by effluents and adsorption accounted for 42% ± 7% and 58% ± 5%, 57% ± 7% and 43% ± 6%, and 84% ± 6% and 16% ± 6% of amikacin elimination, respectively. There was a linear regression between flowrates and amikacin clearance: Y = 0.6 X ± 1.7 (R2 = 0.9782). Conversely, there was a linear inverse correlation between the magnitude of amikacin adsorption and flowrate: Y = -16.9 X ± 84.1 (R2 = 0.9976). CONCLUSION: Low flowrates resulted in predominant elimination by adsorption, accounting for 58% of the elimination of amikacin from the central compartment in the continuous filtration mode at 1500 mL/h of flowrate. Thereafter, the greater the flowrate, the lower the adsorption of amikacin in a linear manner. Flowrate is a major determinant of adsorption of amikacin. There was an about 17% decrease in the rate of adsorption per increase in the flowrate of 1 L/min.

Continuous renal replacement therapy in the treatment of severe hyperkalemia: An in vitro study.

INTRODUCTION: Continuous renal replacement therapy is not presently recommended in the treatment of life-threatening hyperkalemia. There are no specific recommendations in hemodialysis to treat hyperkalemia. We hypothesized an in vitro model may provide valuable information on the usefulness of continuous renal replacement therapy to treat severe hyperkalemia. METHODS: A potassium-free solute was used instead of diluted blood for continuous renal replacement therapy with a simulated blood flowrate set at 200 mL/min. The mode of elimination included continuous filtration, continuous dialysis, and continuous diafiltration using a flowrate of 4000 mL/min for continuous filtration and continuous dialysis modes, and a ratio of 2500/1500 in the continuous diafiltration mode. RESULTS: The mean initial potassium in the central compartment was 10.1 ± 0.4 mmol/L. The clearances in the continuous diafiltration, continuous filtration, and continuous dialysis were 3.4 ± 0.5, 3.6 ± 0.1, and 3.7 ± 0.1 L/h, respectively, not significantly different. Continuous dialysis resulted in the lowest workload for staff. Increasing the continuous dialysis flowrates from 2000 to 8000 mL/h increased clearance from 2.3 ± 0.3 to 6.2 ± 0.8 L/h. The delays in decreasing the potassium concentration to 5.5 mmol/L dropped from 120 to 45 min, respectively. Potassium eliminated in the first hour increased from 18 to 38 mmol that compared favorably with hemodialysis. Decrease in simulated blood flowrate from 200 to 50 mL/min moderately but significantly decreased the clearance from 3.7 to 3.0 L/h. CONCLUSION: Hyperkalemia is efficiently treated by continuous renal replacement therapy using the dialysis mode. Caution is needed to prevent the onset of severe hypokalemia within 40 min after initiation of the session.

A clinical risk score for pulmonary artery thrombosis during acute chest syndrome in adult patients with sickle cell disease.

Pulmonary artery thrombosis (PAT) is involved in lung vascular dysfunction during acute chest syndrome (ACS) complicating sickle cell disease (SCD). No clinical score is available to identify patients eligible for multi-detector computed tomography (MDCT) angiography during ACS. This retrospective study aimed to develop a risk score for PAT during ACS (PAT-ACS risk score). Patients with SCD were investigated by MDCT during ACS. A logistic regression was performed to determine independent risks factors for PAT and to build the PAT-ACS risk score. A total of 43 episodes (11·9%) of PAT were diagnosed in 361 episodes of ACS. Multivariate analysis identified four risk factors, which were included in the PAT-ACS risk score: a baseline haemoglobin >82 g/l, the lack of a triggering factor for ACS, a platelet count >440 × 109 /l and a PaCO2 <38 mmHg at ACS diagnosis. The area under the receiver operating characteristic curve for the PAT-ACS risk score was 0·74 (95% confidence interval [CI] 0·69-0·79) and differed from that of the revised Geneva score (0·63 (95% CI 0·58-0·69); P = 0·04). The negative predictive value of a PAT-ACS risk score ≥2 was 94%. In conclusion, we propose a simple clinical risk score to identify SCD patients at high risk of PAT during ACS.