Comparison of the effect of venovenous versus venoarterial extracorporeal membrane oxygenation on renal blood flow in newborn lambs

Sedation and analgesia requirements during venovenous extracorporeal membrane oxygenation in acute respiratory distress syndrome patients

INTRODUCTION

The purpose of this study is to describe sedation and analgesia management, and identify the factors associated with increased demand for medication in acute respiratory distress syndrome (ARDS) patients receiving venovenous extracorporeal membrane oxygenation (VV-ECMO).

METHODS

This retrospective, single-center study included consecutive adult ARDS patients who received VV-ECMO for at least 24 hours from January 2018 to December 2020 in a comprehensive intensive care unit. The electronic medical records were retrospectively reviewed to collect data.

RESULTS

Forty-two adult patients meeting the inclusion criteria were included in the study. Midazolam, sufentanil, and remifentanil were main sedatives and analgesics used in the patient population. The morphine equivalents, representative of the demand for opioids, was 512.9 (IQR, 294.5, 798.2) mg/day. The midazolam equivalents, representative of benzodiazepine requirement, was 279.6 (IQR, 208.8, 384.5) mg/day. The levels of serum creatinine, total bilirubin, lactic acid, SOFA score, and APACHE Ⅱ score at cannulation were found to be associated with opiate or benzodiazepine requirements. Multiple linear regression analysis revealed a linear correlation between midazolam equivalents and morphine equivalents (p < 0.001). In addition, there was a negative linear correlation between Acute Physiology and Chronic Health Evaluation Ⅱ (APACHE Ⅱ) score and midazolam equivalents (p = 0.024).

CONCLUSIONS

The sedation and analgesia requirements of ARDS patients receiving VV-ECMO often increase simultaneously. More large-scale studies are needed to confirm the risk factors for increased sedation and analgesia needs in patients supported on VV-ECMO.

Disturbed Cerebral Circulation during Opening of the Venoarterial Bypass Bridge in Extracorporeal Membrane Oxygenation

Purpose

To describe the effects on cerebral blood flow velocity (CBFV) of intermittent opening of the venoarterial bridge (VA bridge) during venoarterial extracorporeal membrane oxygenation (VA-ECMO).

Study design

Prospective study in 22 newborns during VA-ECMO. CBFV was measured in the perical-losal artery by Doppler ultrasound. Changes in peak systolic flow velocity (PSV), end diastolic flow velocity (EDV) and time-averaged mean flow velocity (TAM) on day 1, 2, 3, and 5 and at low ECMO flow (50–150 ml/min) were analyzed (mean percentage±standard deviation (t-tests, p<0.05)). Changes >25% were considered relevant. The relationship between changes in CBFV and ECMO flow rate (Pearson correlation, p<0.01) was studied.

Results

Opening of the VA bridge resulted in statistically significant and relevant decreases in PSV (35 ± 18%), EDV (93 ± 15%) and TAM (68 ± 13%), persisting during the consecutive days of treatment. Smaller changes in CBFV at low ECMO flow were statistically significant and mostly relevant: PSV (15 ± 7%), EDV (76 ± 21%) and TAM (40 ± 12%). Changes in CBFV were positively correlated to the ECMO flow. Conclusion: Use of the VA bridge results in significant and relevant ECMO flow-dependent changes in CBFV, persisting during the treatment. The VA bridge should be used in such a way as to allow regular unclamping to be omitted.

In-parallel connected intermittent hemodialysis through ECMO does not affect hemodynamic parameters derived from transpulmonary thermodilution

Introduction:

We report a case of renal replacement therapy (RRT) during extracorporeal membrane oxygenation (ECMO) via a single venous access and analyze the feasibility of transpulmonary thermodilution (TPTD) for hemodynamic monitoring.

Case report:

ECMO and RRT connected into the ECMO-extracorporeal circuit were performed via a single venous access because of multiple venous thromboses. An indicator for TPTD and pulse contour analysis (PCA) was applied into the central venous catheter (CVC) placed in the right vena jugularis. TPTD and PCA demonstrated comparable cardiac index.

Discussion:

Congruent data for TPTD and PCA could be observed during TPTD and PCA measurements before ECMO, after ECMO and during ECMO and RRT. This might be explained by high blood flow having the lowest impact on TPTD by venous drainage in the femoral vein/distal vena cava and the TPTD indicator injection using the jugular CVC, as reported in our case.

Conclusion:

Hemodynamic monitoring using TPTD and PCA during ECMO/RRT is feasible and provides reliable results.

Extracorporeal Membrane Oxygenation and the Kidney

BACKGROUND

Extracorporeal membrane oxygenation (ECMO) is an effective therapy for patients with reversible cardiac and/or respiratory failure. Acute kidney injury (AKI) often occurs in patients supported with ECMO; it frequently evolves into chronic kidney damage or end-stage renal disease and is associated with a reported 4-fold increase in mortality rate. Although AKI is generally due to the hemodynamic alterations associated with the baseline disease, ECMO itself may contribute to maintaining kidney dysfunction through several mechanisms.

SUMMARY

AKI may be related to conditions derived from or associated with extracorporeal therapy, leading to a reduction in renal oxygen delivery and/or to inflammatory damage. In particular, during pathological conditions requiring ECMO, the biological defense mechanisms maintaining central perfusion by a reduction of perfusion to peripheral organs (such as the kidney) have been identified as pretreatment and patient-related risk factors for AKI. Hormonal pathways are also impaired in patients supported with ECMO, leading to failures in mechanisms of renal homeostasis and worsening fluid overload. Finally, inflammatory damage, due to the primary disease, heart and lung crosstalk with the kidney or associated with extracorporeal therapy itself, may further increase the susceptibility to AKI. Renal replacement therapy can be integrated into the main extracorporeal circuit during ECMO to provide for optimal fluid management and removal of inflammatory mediators.

KEY MESSAGES

AKI is frequently observed in patients supported with ECMO. The pathophysiology of the associated AKI is chiefly related to a reduction in renal oxygen delivery and/or to inflammatory damage. Risk factors for AKI are associated with a patient's underlying disease and ECMO-related conditions.

Renal replacement therapy in critically ill patients receiving extracorporeal membrane oxygenation

Extracorporeal membrane oxygenation (ECMO) is a lifesaving procedure used in neonates, children, and adults with severe, reversible, cardiopulmonary failure. On the basis of single-center studies, the incidence of AKI occurs in 70%-85% of ECMO patients. Those with AKI and those who require renal replacement therapy (RRT) are at high risk for mortality, independent of potentially confounding variables. Fluid overload is common in ECMO patients, and is one of the main indications for RRT. RRT to maintain fluid balance and metabolic control is common in some but not all centers. RRT on ECMO can be performed via an in-line hemofilter or by incorporating a standard continuous renal replacement machine into the ECMO circuit. Both of these methods require specific technical considerations to provide safe and effective RRT. This review summarizes available epidemiologic data and how they apply to our understanding of AKI pathophysiology during ECMO, identifies indications for RRT while on ECMO, reviews technical elements for RRT application in the setting of ECMO, and finally identifies specific research-focused questions that need to be addressed to improve outcomes in this at-risk population.

A tale of two bridges: effect of the bloodless bridge on renal function and blood pressure in neonates managed with venoarterial extracorporeal membrane oxygenation

OBJECTIVE

To investigate if a change in bridge design of the extracorporeal membrane oxygenation (ECMO) circuit had an impact on renal function and blood pressure in neonates requiring venoarterial ECMO support.

DESIGN

: Retrospective chart review.

SETTING

A tertiary care neonatal intensive care unit and ECMO center.

PATIENTS

The medical records of neonates admitted to the neonatal intensive care unit and treated with venoarterial ECMO were reviewed. Data were collected on 50 consecutive neonates treated previous to (prebridge group) and following (postbridge group) transition to a new bridge design on the ECMO circuit.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Gestational age, gender, racial distribution, and use of hypertensive therapy were similar between the two groups. Daily blood urea nitrogen, serum creatinine, urine output, fluid balance, and average and maximum systolic and mean arterial blood pressures were recorded for the first 3 days on bypass. The postbridge group had lower maximum mean arterial blood pressure and systolic blood pressure on day 2 of ECMO and lower average mean arterial blood pressure and systolic blood pressure on days 2 and 3 of ECMO. These differences remained significant after controlling for covariates in a multiple regression model. A higher percentage of patients were hypertensive (mean arterial blood pressure >60) in the prebridge group compared with the postbridge group. There were no differences in blood urea nitrogen, serum creatinine, fluid balance, and urine output between the two groups.

CONCLUSIONS

Patients managed on venoarterial ECMO after the transition to the "bloodless" bridge had less hypertension compared with those managed before the bridge change. This may reflect improved maintenance of renal perfusion associated with transition to an ECMO bridge design that does not require intermittent circulation with associated arterial-venous shunting.

Continuous renal replacement therapy in neonates and young infants during extracorporeal membrane oxygenation

Extracorporeal membrane oxygenation (ECMO) is a therapy that ensures adequate tissue oxygen delivery in patients suffering cardiac and/or respiratory failure that are unresponsive to conventional therapy. During ECMO, it is common to see a decrease in urine output that may be associated with acute renal failure. In this context, continuous renal replacement therapy (CRRT) should be considered. Our aim is to evaluate a pioneer experience in Latin America, related to the use of CRRT in a group of neonatal-pediatric patients during ECMO. We conducted a retrospective review of patients treated with ECMO at our institution between May 2003 and May 2005. Twelve infants were treated with ECMO, six of them also underwent CRRT. The main reasons for CRRT initiation were fluid overload and progressive azotemia. Observed complications were clots in the filter and excessive ultrafiltration. CRRT was successful in fluid management and solute clearance in all patients. Discharge survival rate was 83%, all of them with normal renal function. Concurrent CRRT with ECMO is technically feasible and efficacious in the management of fluid overload and solute clearance. We report the first experience with these therapies in a Latin American neonatal-pediatric ECMO program associated with the Extracorporeal Life Support Organization.