Delayed extracorporeal membrane oxygenation in children after cardiac surgery: two-institution experience.

OBJECTIVE: There are limited data on the outcomes of children receiving delayed (≥7 days) extracorporeal membrane oxygenation after cardiac surgery. The primary aim of this project is to identify the aetiology and outcomes of extracorporeal membrane oxygenation in children receiving delayed (≥7 days) extracorporeal membrane oxygenation after cardiac surgery. PATIENTS AND METHODS: We conducted a retrospective review of all children ≤18 years supported with delayed extracorporeal membrane oxygenation after cardiac surgery between the period January, 2001 and March, 2012 at the Arkansas Children's Hospital, United States of America, and Royal Children's Hospital, Australia. The data collected in our study included patient demographic information, diagnoses, extracorporeal membrane oxygenation indication, extracorporeal membrane oxygenation support details, medical and surgical history, laboratory, microbiological, and radiographic data, information on organ dysfunction, complications, and patient outcomes. The outcome variables evaluated in this report included: survival to hospital discharge and current survival with emphasis on neurological, renal, pulmonary, and other end-organ function. RESULTS: During the study period, 423 patients undergoing cardiac surgery were supported with extracorporeal membrane oxygenation at two institutions, with a survival of 232 patients (55%). Of these, 371 patients received extracorporeal membrane oxygenation <7 days after cardiac surgery, with a survival of 205 (55%) patients, and 52 patients received extracorporeal membrane oxygenation ≥7 days after cardiac surgery, with a survival of 27 (52%) patients. The median duration of extracorporeal membrane oxygenation run for the study cohort was 5 days (interquartile range: 3, 10). In all, 14 patients (25%) received extracorporeal membrane oxygenation during active cardiopulmonary resuscitation with chest compressions. There were 24 patients (44%) who received dialysis while being on extracorporeal membrane oxygenation. There were eight patients (15%) who had positive blood cultures and four patients (7%) who had positive urine cultures while being on extracorporeal membrane oxygenation. There were nine patients (16%) who had bleeding complications associated with extracorporeal membrane oxygenation runs. There were 10 patients (18%) who had cerebrovascular thromboembolic events associated with extracorporeal membrane oxygenation runs. Of these, 19 patients are still alive with significant comorbidities. CONCLUSIONS: This study demonstrates that mortality outcomes are comparable among children receiving extracorporeal membrane oxygenation ≥7 days and <7 days after cardiac surgery. The proportion of patients receiving extracorporeal membrane oxygenation ≥7 days is small and the aetiology diverse.

Osh6 overexpression extends the lifespan of yeast by increasing vacuole fusion.

In yeast cells, the vacuole divides and fuses in each round of cell cycle. While mutants defective in vacuole fusion are "wild type" for vegetative growth, most have shortened replicative lifespans under caloric restriction (CR) condition, a manipulation that extends lifespan in wild type cells. To explore whether vacuole fusion extends lifespan, we screened for genes that can complement the fusion defect of selected mutants (erg6Δ, a sterol mutant; nyv1Δ,  a mutant involved in the vacuolar SNARE complex and vac8Δ, a vacuolar membrane protein mutant). This screen revealed that Osh6, a member of the oxysterol-binding protein family, can complement the vacuole fusion defect of nyv1Δ, but not erg6Δ or vac8Δ, suggesting that Osh6's function in vacuole fusion is partly dependent on membrane ergosterol and Vac8. To measure the effect of OSH6 on lifespan, we replaced the endogenous promoter of OSH6 with a shorter version of the ERG6 promoter to obtain PERG6-OSH6. This mutant construct significantly extended the replicative lifespan in a wild type background and in a nyv1Δ mutant. Interestingly, PERG6-OSH6 cells were more sensitive to drugs that inhibit the activity of the TOR complex 1 (TORC1) than wild type cells. Moreover, a PERG6-OSH6 tor1Δ double mutant demonstrated a greatly shortened lifespan, suggesting a genetic interaction between Osh6 and Tor1. Since active TORC1 stimulates vacuole scission and CR downregulates TORC1, Osh6 may link these two pathways by adjusting vacuolar membrane organization to extend lifespan.