Flexible Bronchoscopy in Pediatric Venovenous Extracorporeal Membrane Oxygenation

BACKGROUND

Pediatric patients with ARDS will on occasion need venovenous extracorporeal membrane oxygenation (VV-ECMO) for organ support. As these patients recover, they may benefit from lung recruitment maneuvers including flexible bronchoscopy (FB). The objective of this study was to assess the clinical course of patients who underwent FB while on VV-ECMO for ARDS.

METHODS

This was a secondary analysis of a retrospective multi-center cohort at 10 United States pediatric academic quaternary care centers. Data were collected on 204 subjects age 14 d-18 y on VV-ECMO.

RESULTS

271 FBs were performed on 129 (63%) subjects. Pre-FB tidal volume was 1.8 mL/kg compared to 2.22 mL/kg following FB (P = .007). Dynamic compliance also improved from pre-FB to post-FB (2.23 vs 3.04 mL/cm H₂O, P = .005). There was a low incidence of complications following FB (3.1%). Subjects in the FB group had fewer ECMO-free days (EFDs) (17.9 vs 22.1 d, P < .001), fewer ventilator-free days (VFDs) (40.0 vs 46.5 d, P = .001), and longer ICU length of stay (LOS) (18 vs 32 d, P < .001). Subjects in the early versus late FB group had more EFDs (19.4 vs 15.2 d, P = .003), more VFDs (43.0 vs 34.0 d, P = .004), and shorter ICU LOS (27.5 vs 35.5 d, P = .045). Mortality in the subjects who had at least one FB was 27.1% compared to 40% in the subjects who did not have a FB while on VV-ECMO (P = .057).

CONCLUSIONS

FB can be performed on patients while anticoagulated on VV-ECMO with a low incidence of complications. FB may be beneficial especially when performed early in the course of VV-ECMO.

Tracheostomy and long-term mechanical ventilation in children after veno-venous extracorporeal membrane oxygenation

OBJECTIVE

Our objective is to characterize the incidence of tracheostomy placement and of new requirement for long-term mechanical ventilation after extracorporeal membrane oxygenation (ECMO) among children with acute respiratory failure. We examine whether an association exists between demographics, pre-ECMO and ECMO clinical factors, and the placement of a tracheostomy or need for long-term mechanical ventilation.

METHODS

A retrospective multicenter cohort study was conducted at 10 quaternary care pediatric academic centers, including children supported with veno-venous (V-V) ECMO from 2011 to 2016.

RESULTS

Among 202 patients, 136 (67%) survived to ICU discharge. All tracheostomies were placed after ECMO decannulation, in 22 patients, with 19 of those surviving to ICU discharge (14% of survivors). Twelve patients (9% of survivors) were discharged on long-term mechanical ventilation. Tracheostomy placement and discharge on home ventilation were not associated with pre-ECMO severity of illness or pre-existing chronic illness. Patients who received a tracheostomy were older and weighed more than patients who did not receive a tracheostomy, although this association did not exist among patients discharged on home ventilation. ECMO duration was longer in those who received a tracheostomy compared with those who did not, as well as for those discharged on home ventilation, compared to those who were not.

CONCLUSION

The 14% rate for tracheostomy placement and 9% rate for discharge on long-term mechanical ventilation after V-V ECMO are important patient-centered findings. This study informs anticipatory guidance provided to families of patients requiring prolonged respiratory ECMO support, and lays the foundation for future research.

Veno-Venous Extracorporeal Membrane Oxygenation for Children With Cancer or Hematopoietic Cell Transplant: A Ten Center Cohort

We performed a multicenter retrospective cohort study of children with 14 days to 18 years of age in the United States from 2011 to 2016 with cancer or hematopoietic cell transplant (HCT) who were supported with veno-venous extracorporeal membrane oxygenation (V-V ECMO). We compared the outcomes of children with oncological diagnoses or HCT supported with V-V ECMO to other children who have received V-V ECMO support. In this cohort of 204 patients supported with V-V ECMO, 30 (15%) had a diagnosis of cancer or a history of HCT. There were 21 patients who had oncological diagnoses without HCT and 9 children were post-HCT. The oncology/HCT group had a higher overall ICU mortality (67% vs. 28%, P < 0.001), mortality on ECMO (43% vs. 21%, P < 0.01), and ICU mortality among ECMO survivors (35% vs. 8%, P < 0.01). The oncology/HCT group had a higher rate of conversion to veno-arterial (V-A) ECMO (23% vs. 9%, P = 0.02) (RR, 2.5; 95% CI, 1.1-5.6). Children with cancer or HCT were older (6.6 vs. 2.9 years, P = 0.02) and had higher creatinine levels (0.65 vs. 0.4 mg/dL, P = 0.04) but were similar to the rest of the cohort for other pre-ECMO variables. For post-HCT patients, survival was significantly worse for those whose indication for HCT was cancer or immunodeficiency (0/6) as compared to other nonmalignant indications (3/3) (P = 0.01).

Mechanical Ventilation in Children on Venovenous ECMO

BACKGROUND

Venovenous extracorporeal membrane oxygenation (VV-ECMO) is used when mechanical ventilation can no longer support oxygenation or ventilation, or if the risk of ventilator-induced lung injury is considered excessive. The optimum mechanical ventilation strategy once on ECMO is unknown. We sought to describe the practice of mechanical ventilation in children on VV-ECMO and to determine whether mechanical ventilation practices are associated with clinical outcomes.

METHODS

We conducted a multicenter retrospective cohort study in 10 pediatric academic centers in the United States. Children age 14 d through 18 y on VV-ECMO from 2011 to 2016 were included. Exclusion criteria were preexisting chronic respiratory failure, primary diagnosis of asthma, cyanotic heart disease, or ECMO as a bridge to lung transplant.

RESULTS

Conventional mechanical ventilation was used in about 75% of children on VV-ECMO; the remaining subjects were managed with a variety of approaches. With the exception of PEEP, there was large variation in ventilator settings. Ventilator mode and pressure settings were not associated with survival. Mean ventilator F_IO2 on days 1-3 was higher in nonsurvivors than in survivors (0.5 vs 0.4, P = .009). In univariate analysis, other risk factors for mortality were female gender, higher Pediatric Risk Estimate Score for Children Using Extracorporeal Respiratory Support (Ped-RESCUERS), diagnosis of cancer or stem cell transplant, and number of days intubated prior to initiation of ECMO (all P < .05). In multivariate analysis, ventilator F_IO2 was significantly associated with mortality (odds ratio 1.38 for each 0.1 increase in F_IO2 , 95% CI 1.09-1.75). Mortality was higher in subjects on high ventilator F_IO2 (≥ 0.5) compared to low ventilator F_IO2 (> 0.5) (46% vs 22%, P = .001).

CONCLUSIONS

Ventilator mode and some settings vary in practice. The only ventilator setting associated with mortality was F_IO2 , even after adjustment for disease severity. Ventilator F_IO2 is a modifiable setting that may contribute to mortality in children on VV-ECMO.