Hemodynamic impact of the connection to continuous renal replacement therapy in critically ill children

Abstract

BackgroundContinuous renal replacement therapy (CRRT) is the treatment of choice for critically ill children with acute kidney injury. Hypotension after starting CRRT is frequent but very few studies have analyzed its incidence and clinical relevance.MethodsA prospective, observational study was performed including critically ill children treated with CRRT between 2010 and 2014. Hemodynamic data and connection characteristics were collected before, during, and 60 min after CRRT circuit connection. Hypotension with the connection was defined as a decrease in > 20% of the mean arterial pressure from baseline or when intravenous fluid resuscitation or an increase in vasopressors was required.ResultsOne hundred sixty-one connections in 36 children (median age 18.8 months) were analyzed. Twenty-eight patients (77.8%) were in the postoperative period of cardiac surgery, 94% had mechanical ventilation, and 86.1% had vasopressors. The heparinized circuit priming solution was discarded in 8.7% and infused to the patient in 18% of the connections. The circuit was re-primed in the remaining 73.3% using albumin (79.3%), red blood cells (4.5%), or another crystalloid solution without heparin (16.2%). Hypotension occurred in 49.7% of the connections a median of 5 min after the beginning of the therapy. Fluid resuscitation was required in 38.5% and the dose of vasopressors was increased in 12.4% of the connections. There was no relationship between hypotension and age or weight. Re-priming the circuit with albumin reduced the incidence of hypotension from 71.4 to 44.6% (p = 0.004).ConclusionsHypotension after the connection to CRRT is very frequent in critically ill children. Re-priming the circuit with albumin could improve hemodynamics during connection.

Changes in hemodynamics, renal blood flow and urine output during continuous renal replacement therapies

“…As reported in our previous study, a significant decrease in blood pressure, CI and PVRI occurred when starting CRRT in both groups 15 . No statistically significant differences were found in blood pressure between groups.…”

“…An 8 F double lumen dialysis catheter was surgically inserted in the external jugular vein. www.nature.com/scientificreports/ An ultrasonic transit-time flow probe (HDQ1.5FSB, Transonic Systems Inc., Ithaca, New York, USA) was placed on the left renal artery for continuous renal blood flow monitoring, as described in our previous study 15 . Bladder was directly catheterized through a suprapubic cystostomy to assess UO.…”

“…CRRT-related hypotension or CRRT-related hemodynamic instability (CRRT-HI) is a relatively common complication 10 , 13 – 15 . Our research group has been studying the possible mechanisms leading to hypotension during the connection to CRRT for several years.…”

“…Our research group has been studying the possible mechanisms leading to hypotension during the connection to CRRT for several years. A previous study revealed that initiating CRRT was accompanied by a significant decrease in arterial blood pressure, cardiac index and urine output (UO) in hemodynamically stable piglets 15 . Normal physiological responses to hypotension such as tachycardia and increased peripheral vascular resistance seemed to be impaired during connection.…”

Continuous Renal Replacement Therapy

“…90 Hypotension may also be seen upon initiation of treatment, particularly if the circuit prime is not reinfused; this result has been of particular concern in pediatric patients and may be mitigated by using albumin to prime the circuit. 91 Although increases in blood flow through the extracorporeal circuit were associated with increased circuit volume and hypotension with older dialysis systems, there is minimal change in extracorporeal volume and thus negligible hemodynamic stress associated with changes in blood flow using current CRRT technology and hollow fiber filters. 90,92,93 When hypotension is associated with volume depletion, it should be treated with volume reinfusion and adjustment in ultrafiltration targets; in other circumstances, alternative etiologies should be considered and the hypotension managed with titration of vasopressor support.…”