Extracorporeal life support for acute respiratory distress syndromes

Clinical effect of early enteral nutrition support on critically ill neonates with extracorporeal membrane oxygenation

OBJECTIVE

To investigate the feasibility and clinical outcomes of early enteral nutrition (EN) in critically ill neonates supported by extracorporeal membrane oxygenation (ECMO).

METHODS

We retrospectively analyzed the clinical data of 16 critically ill neonates who received ECMO support for respiratory and circulatory failure from July 2021 to December 2022 at our center. The patients were divided into two groups: the early EN group (< 24 h) and the late EN group (> 24 h). The related clinical and nutrition-related indicators between the groups were compared.

RESULTS

There was a significant difference in the time from ECMO treatment to the start of EN between the early EN group (9 patients, 56.2%) and the late EN group (7 patients, 43.8%) (P < 0.05). However, there were no significant differences in ECMO duration, hospitalization time, vasoactive-inotropic score (VIS), intestinal oxygen saturation, or routine stool occult blood (OB) test between the two groups (all P > 0.05). The incidence of complications such as intestinal obstruction, abdominal distension, diarrhea, and necrotizing enterocolitis (NEC) was slightly lower in the early EN group, but the differences were not statistically significant (all P > 0.05). The early EN group had a shorter time [3.6 (3.5, 5) vs. 7.5 (5.9, 8.5) d] to reach full gastrointestinal nutrition compared to the late EN group (P < 0.05).

CONCLUSION

Providing early nutritional support through enteral feeding to critically ill neonates receiving ECMO treatment is both safe and practical, but close monitoring of clinical and nutritional indicators is essential.

Differential hypoxemia and the clinical significance of venous drainage position during extracorporeal membrane oxygenation

Differential hypoxemia (DH) has been recognized as a clinical problem during veno-arterial extracorporeal membrane oxygenation (VA ECMO) although its features and consequences have not been fully elucidated.

This single center retrospective study aimed to investigate the clinical characteristics of patients manifesting DH as well as the impact of repositioning the drainage point from the inferior vena cava (IVC) to the superior vena cava to alleviate DH.

All patients (>15 years) commenced on VA ECMO at our center between 2009 and 2020 were screened. Of 472 eligible patients seven were identified with severe DH. All patients had the drainage cannula tip in the IVC or at the junction between the IVC and right atrium.

The mean peripheral capillary saturation increased from 54 (±6.6) to 86 (±6.6) %, (p = <0.001) after repositioning of the cannula. Pre-oxygenator saturation increased from 62 (±8.9) % prior to adjustment to 74 (±3.7) %, (p = 0.016) after repositioning. Plasma lactate tended to decrease within 24 h after adjustment. Five patients (71%) survived ECMO treatment, to discharge from hospital, and were alive at 1-year follow-up.

Although DH has been described in several studies, the condition has not been investigated in a clinical setting comparing the effect on upper body saturation before and after repositioning of the drainage cannula. This study shows that moving the drainage zone into the upper part of the body has a marked positive effect on upper body saturation in patients with DH.

Cannulation for veno-venous extracorporeal membrane oxygenation

Extracorporeal membrane oxygenation (ECMO) is described as a modified, smaller cardiopulmonary bypass circuit. The veno-venous (VV) ECMO circuit drains venous blood, oxygenate the blood, and pump the blood back into the same venous compartment. Draining and reinfusing in the same compartment means there are a risk of recirculation. The draining position within the venous system, ECMO pump flow, return flow position within the venous system and the patients cardiac output (CO) all have an impact on recirculation. Using two single lumen cannulas or one dual lumen cannula, but also the design of the venous cannula, can have an impact on where within the venous system the cannula is draining blood and will affect the efficiency of the ECMO circuit. VV ECMO can be performed with different cannulation strategies. The use of two single lumen cannulas draining in inferior vena cava (IVC) and reinfusing in superior vena cava (SVC) or draining in SVC and reinfusing in IVC, or one dual lumen cannula inserted in right jugular vein is all possible cannulation strategies. Independent of cannulation strategy there will be a risk of recirculation. Efficiency can be reasonable in either strategy if the cannulas are carefully positioned and monitored during the dynamic procedure of pulmonary disease. The disadvantage draining from IVC only occurs when there is a need for converting from VV to veno-arterial (VA) ECMO, reinfusing in the femoral artery. Then draining from SVC is the most efficient strategy, draining low saturated venous blood, and also means low risk of dual circulation.

Pharmacotherapy during pediatric extracorporeal membrane oxygenation: a review

INTRODUCTION

Pediatric critical illness and associated alterations in organ function can change drug pharmacokinetics (PK). Extracorporeal membrane oxygenation (ECMO), a life-saving therapy for severe cardiac and/or respiratory failure, causes additional PK alterations that affect drug disposition.

AREAS COVERED

The purposes of this review are to discuss the PK changes that occur during ECMO, the associated therapeutic implications, and to review PK literature relevant to pediatric ECMO. We discuss various classes of drugs commonly used for pediatric patients on ECMO, including sedatives, analgesics, antimicrobials and cardiovascular drugs. Finally, we discuss future areas of research and recommend strategies for future pediatric ECMO pharmacologic investigations.

EXPERT OPINION

Clinicians caring for pediatric patients treated with ECMO must have an understanding of PK alterations that could lead to either therapeutic failures or increased drug toxicity during this life-saving therapy. Limited data currently exist for optimal drug dosing in pediatric populations who are treated with ECMO. While there are clear challenges to conducting and analyzing data associated with clinical pharmacokinetic-pharmacodynamic studies of children on ECMO, we present techniques to address these challenges. Improved understanding of the physiology and drug disposition during ECMO combined with PK-PD modeling will allow for more adaptable and individualized dosing schemes.

Diverse Morbidity and Mortality Among Infants Treated with Venoarterial Extracorporeal Membrane Oxygenation

Background: Venoarterial extracorporeal membrane oxygenation (VA-ECMO) is utilized for cardiopulmonary failure. We aimed to qualify and quantify the predictors of morbidity and mortality in infants requiring VA-ECMO.

Methods: Data was collected from 170 centers participating in the extracorporeal life support organization (ELSO) registry. Relationships between in-hospital mortality and risk factors were assessed using logistic regression. Survival was defined as being discharged from the hospital.

Results: Six hundred and sixty-two eligible records were reviewed. Mortality occurred in 303 (46%) infants. Congenital diaphragmatic hernia patients (OR=3.83, 95% CI 1.96-7.49, p<0.001), cardiac failure with associated shock (OR= 2.90, 95% CI 1.46-5.77, p=0.002), and pulmonary failure including respiratory distress syndrome (OR=4.06, 95% CI 1.72-9.58, p=0.001) had the highest odds of mortality in this cohort. Birth weight (BW) < 3 kg (OR=1.83, 95% CI 1.21-2.78, p=0.004), E-CPR (OR=3.35, 95% CI 1.57-7.15, p=0.002), hemofiltration (OR=2.04, 95% CI 1.32-3.16, p=0.001), and dialysis (OR=6.13, 95% CI 1.70-22.1, p<0.001) were all independent predictors of mortality.

Conclusion: Infants requiring VA-ECMO experience diverse sequelae and their mortality are high.

Survival of patients with cystic fibrosis on ECMO: analysis of the Extracorporeal Life Support Organization Registry

Progressive respiratory failure is a common cause of death in patients with cystic fibrosis (CF). Although this may be related to the disease process itself, acute infectious problems may lead to respiratory failure requiring mechanical ventilation. Given the progressive nature of the disorder, some have suggested that the use of extracorporeal membrane oxygenation (ECMO) is contraindicated. The current study retrospectively reviewed the Extracorporeal Life Support Organization (ELSO) Registry to evaluate the outcomes following the use of ECMO in patients with CF. A total of 73 ECMO runs were identified in CF patients. There were 33 who received VV ECMO, 32 on VA ECMO, and 8 who received combined VA and VA ECMO. The overall survival rate for the cohort was 52% (38 of 73 patients). There was no difference in survival when comparing VA and VV ECMO. We noted an increasing trend for VV ECMO for this patient population over this time period. These data further support the need for a prospective study to evaluate outcomes following ECMO in this population with standardization of care across multiple centers.

Extracorporeal membrane oxygenation and retransplantation in lung transplantation: an analysis of the UNOS registry

BACKGROUND

Despite limited organ availability, extracorporeal membrane oxygenation (ECMO) and retransplantation are becoming more commonplace.

METHODS

Using the United Network for Organ Sharing (UNOS) database, we evaluated survival of patients treated with ECMO before lung transplantation and undergoing retransplantation. A query identified cadaveric recipients from 2001 to 2012 over the age of 6 years.

RESULTS

Of 15,772 lung recipients, 15 583 never received ECMO, whereas 189 did. Mean age was 52.1 ± 14.4 versus 46.8 ± 16.5 years for non-ECMO and ECMO groups, respectively (p < 0.0001). Using Kaplan-Meier method, there were survival differences between ECMO and non-ECMO groups (p < 0.0001) and first-time transplants with and without ECMO to retransplants with and without ECMO (p < 0.0001). The proportional hazards model identified higher risk with ECMO use in idiopathic pulmonary fibrosis (hazard ratio [HR] 1.09; 95 % confidence interval (CI), 1.02-1.17; p = 0.014) and retransplants (HR 1.77; 95 % CI, 1.55-2.03; p < 0.0001).

CONCLUSIONS

Survival for retransplantation was similar to ECMO as a primary option with significant mortality associated with ECMO use in patients with idiopathic pulmonary fibrosis and retransplants.