Improved Outcomes with Negative Pressure Ventilation (NPV) during Normothermic Ex Vivo Lung Perfusion
Bibliographic record
Abstract
Introduction: Normothermic Ex Vivo Lung Perfusion (EVLP) has increased the rate of donor organ utilization, and increased volumes of lung transplantation at centers that have adopted the technology. Current ventilation methodology for EVLP uses Positive Pressure Ventilation (PPV) with all clinically available devices. We developed a novel ventilation system that replicates in vivo lung ventilation wherein a negative pressure is applied to the pleural surface of the lung (NPV). We hypothesize that NPV would be superior to PPV during EVLP. Methods: A fully automated NPV EVLP platform was developed and compared to conventional (PPV) EVLP. Pig and human lungs were perfused for 12 hours and physiologic parameters, cytokine profile, bronchopleural fistula (BPF) and edema formation were analyzed. A total of 24 pigs were perfused, divided equally into 4 groups based on ventilation strategy and perfusate composition: Acellular-NPV vs. Acellular-PPV, and, Cellular-NPV vs. Cellular-PPV (Acellular: STEEN solution™ & Cellular: packed Red Blood Cells + STEEN solution™). Preliminary unutilized human lungs compared Cellular-NPV (N = 2) and Cellular-PPV (N = 2). Results: Using ANOVA pairwise comparison (mean ± SE), pig and human lungs showed stable trends in lung oxygenation (>400 mmHg) and physiological parameters. Cytokine analysis of the pig lungs showed significantly lower TNFa, IL-6, and IL-8 production with an NPV strategy regardless of perfusate (p < 0.05). Moreover, there was a 38% lower incidence of BPF with a NPV vs. PPV strategy (p = 0.02). Edema after 12 hours of EVLP for pRBCs using NPV and PPV were 15.4 ± 2.0% and 40.6 ± 9.0% (p < 0.05); while with acellular using NPV and PPV it was 33.2 ± 6.4% and 88.1 ± 11.0% (p < 0.05) (Figure 1), respectively. Interestingly, with human lung perfusion we found edema at 12 hours for pRBCs using NPV and PPV were −10.8 ± 9.0% and 37.1 ± 9.0% (p < 0.05) (Figure 2), respectively. Conclusions: Negative pressure ventilation (NPV) is potentially more beneficial compared to traditional positive pressure ventilation (PPV), with significantly less inflammation, bullae, and edema formation during extended EVLP for both perfusate groups. The value of a NPV strategy may lead to further improvements to currently available clinical EVLP platforms. CIHR. CNTRP. UHF.FIGURE 1: Edema comparison between Negative Pressure Ventilation (NPV) EVL and Positive Pressure (PPV) EVLPand their perspective perspective perfusate groups.FIGURE 2: Negative edema formation with negative pressure ventilation (NPV) compared to positive pressure ventilation (PPV).
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".