High-Flow Oxygen Therapy in Tracheostomized Subjects With Prolonged Mechanical Ventilation: A Randomized Crossover Physiologic Study
Bibliographic record
Abstract
BACKGROUND: High-flow oxygen therapy via tracheostomy (HFT) can be used in tracheostomized patients during ventilator disconnection. The physiologic effects of this technique are unknown. We hypothesized that HFT would reduce inspiratory effort and improve breathing pattern compared to conventional oxygen therapy via T-tube. This study aimed to evaluate the physiologic effects of HFT compared to conventional O 2 in patients with prolonged mechanical ventilation. METHODS: A randomized crossover physiologic study was conducted in adult tracheostomized patients who experienced temporary periods of ventilator disconnection. Subjects were ventilated with pressure support ventilation (PSV) for 15 min and were then randomly assigned to HFT or conventional O 2 via T-tube for 30 min. After a washout period, subjects were switched to the other system. Esophageal pressure (P es ), breathing frequency, blood pressure, heart rate, <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll"> <mml:mrow> <mml:msub> <mml:mtext mathvariant="bold">S</mml:mtext> <mml:mrow> <mml:msub> <mml:mrow> <mml:mtext mathvariant="bold">pO</mml:mtext> </mml:mrow> <mml:mtext mathvariant="bold">2</mml:mtext> </mml:msub> </mml:mrow> </mml:msub> </mml:mrow> </mml:math> , and transcutaneously measured pressure of carbon dioxide ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll"> <mml:mrow> <mml:msub> <mml:mtext mathvariant="bold">P</mml:mtext> <mml:mrow> <mml:msub> <mml:mrow> <mml:mtext mathvariant="bold">tcCO</mml:mtext> </mml:mrow> <mml:mtext mathvariant="bold">2</mml:mtext> </mml:msub> </mml:mrow> </mml:msub> </mml:mrow> </mml:math> ) were recorded. The primary outcome was inspiratory effort as determined by the simplified esophageal pressure-time product (sPTP es ). Secondary outcomes were P es swing, breathing frequency, heart rate, mean arterial pressure, <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll"> <mml:mrow> <mml:msub> <mml:mtext mathvariant="bold">S</mml:mtext> <mml:mrow> <mml:msub> <mml:mrow> <mml:mtext mathvariant="bold">pO</mml:mtext> </mml:mrow> <mml:mtext mathvariant="bold">2</mml:mtext> </mml:msub> </mml:mrow> </mml:msub> </mml:mrow> </mml:math> , and <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll"> <mml:mrow> <mml:msub> <mml:mtext mathvariant="bold">P</mml:mtext> <mml:mrow> <mml:msub> <mml:mrow> <mml:mtext mathvariant="bold">tcCO</mml:mtext> </mml:mrow> <mml:mtext mathvariant="bold">2</mml:mtext> </mml:msub> </mml:mrow> </mml:msub> </mml:mrow> </mml:math> between groups. RESULTS: Twenty-two subjects were enrolled: sPTP es per minute was significantly higher with HFT and conventional O 2 compared to PSV (153.5 ± 97.9, 163.5 ± 111.3, and 86.8 ± 51.1 cm H 2 O × s/min, respectively, P = .001), but it was not different between HFT and conventional O 2 ( P = .72). Breathing frequency increased significantly after switching from PSV to HFT and conventional O 2 (23 ± 4 vs 26 ± 6 and 23 ± 4 vs 27 ± 5 breaths/min, respectively, P = .001). <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll"> <mml:mrow> <mml:msub> <mml:mtext mathvariant="bold">S</mml:mtext> <mml:mrow> <mml:msub> <mml:mrow> <mml:mtext mathvariant="bold">pO</mml:mtext> </mml:mrow> <mml:mtext mathvariant="bold">2</mml:mtext> </mml:msub> </mml:mrow> </mml:msub> </mml:mrow> </mml:math> was higher with conventional O 2 compared to HFT ( P = .02). No differences in <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll"> <mml:mrow> <mml:msub> <mml:mtext mathvariant="bold">P</mml:mtext> <mml:mrow> <mml:msub> <mml:mrow> <mml:mtext mathvariant="bold">tcCO</mml:mtext> </mml:mrow> <mml:mtext mathvariant="bold">2</mml:mtext> </mml:msub> </mml:mrow> </mml:msub> </mml:mrow> </mml:math> , mean arterial pressure, or heart rate were observed between HFT and conventional O 2 . CONCLUSIONS: Inspiratory effort and breathing frequency increased significantly during unassisted breathing compared to PSV in tracheostomized subjects, but HFT via tracheostomy provided no measurable additional physiologic benefit compared to O 2 therapy via T-tube.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| 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 teacher head, 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".