Intensive Renal Replacement Therapy May Increase Risk for MV Extubation Failure

In critically ill mechanically ventilated patients with acute kidney injury (AKI), more intensive renal replacement therapy (RRT) may lead to a greater risk of failure to extubate, according to a study published in CHEST.

Severe AKI may require support through intermittent or continuous RRT while the kidneys recover function. However, increasing the RRT dose is associated with electrolyte abnormalities such as hypophosphatemia and hypokalemia, enhanced elimination of antibiotics leading to inadequate dosing, excessive nutrient losses such as amino acids and proteins, and lower urine output.

Researchers hypothesized that more intensive renal replacement therapy would have more adverse effects such as longer duration of mechanical ventilation, potentially as a result of phosphate losses or other small solute losses during RRT. Therefore, they conducted a post hoc analysis of the Acute Renal Failure Trial Network study (ClinicalTrials.gov Identifier: NCT00076219) in which more intensive (hemodialysis or sustained low-efficiency dialysis 6 times per week or continuous venovenous hemodiafiltration at 35 mL/kg/h) was compared with less intensive (hemodialysis or sustained low-efficiency dialysis 3 times per week or continuous venovenous hemodiafiltration at 20 mL/kg/h) RRT in 907 critically ill patients with AKI.

Patients who were randomly assigned to more intensive RRT had a 33.3% lower hazard rate of successful extubation (hazard ratio, 0.67; 95% CI, 0.53-0.85; P <.001) compared with patients randomly assigned to less intensive RRT. In addition, patients who received more intensive RRT had on average 2.07 ventilator-free days compared with 3.08 days in those who received less intensive RRT (P <.001) over 14 days from start of the study. 

“Critically ill mechanically ventilated patients randomized to more intensive RRT have longer duration of mechanical ventilation compared to those randomized to less intensive RRT,” concluded the authors. “The reasons for this, such as excessive phosphate loss from more intensive RRT, deserve further study to optimize the safety and effectiveness of CRRT delivery.”

Reference

Sharma S, Kelly YP, Palevsky PM, Waikar SS. Intensity of renal replacement therapy and duration of mechanical ventilation: secondary analysis of the Acute Renal Failure Trial Network study [published online May 25, 2020]. CHEST. doi:10.1016/j.chest.2020.05.542