Instruct: Identify the main category of Medrxiv papers based on the titles and abstracts
Query: Regional pleural strain measurements during mechanical ventilation using ultrasound elastography: A randomised, crossover, proof of concept physiologic study BackgroundMechanical ventilation is a common therapy in operating rooms and intensive care units. When ill-adapted, it can lead to ventilator-induced lung injury (VILI), which is associated with poor outcomes. Excessive regional pulmonary strain is thought to be a major mechanism responsible for VILI. Scarce bedside methods exist to measure regional pulmonary strain. We propose a novel way to measure regional pleural strain using ultrasound elastography.

Research QuestionThe objective of this study was to assess the feasibility and reliability of pleural strain measurement by ultrasound elastography and to determine if elastography parameters would correlate with varying tidal volumes.

Study Design and MethodsA single-blind randomized crossover proof of concept study was conducted July to October 2017 at a tertiary care referral center. Ten patients requiring general anesthesia for elective surgery were recruited. After induction, patients were received tidal volumes of 6, 8, 10 and 12 mL.kg-1 in random order, while pleural ultrasound cineloops were acquired at 4 standardized locations. Ultrasound radiofrequency speckle tracking allowed computing various pleural translation, strain and shear components. These were screened to identify those with the best dose-response with tidal volumes using linear mixed effect models. Goodness-of-fit was assessed by the coefficient of determination. Intraobserver, interobserver and test-retest reliability were calculated using intraclass correlation coefficients.

ResultsAnalysis was possible in 90.7% of ultrasound cineloops. Lateral absolute shear, lateral absolute strain and Von Mises strain varied significantly with tidal volume and offered the best dose-responses and data modelling fits. Point estimates for intraobserver reliability measures were excellent for all 3 parameters (0.94, 0.94 and 0.93, respectively). Point estimates for interobserver (0.84, 0.83 and 0.77, respectively) and test-retest (0.85, 0.82 and 0.76, respectively) reliability measures were good.

InterpretationStrain imaging is feasible and reproducible, and may eventually guide mechanical ventilation strategies in larger cohorts of patients.
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The categories of this paper are: global
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The categories of this paper are: sexual
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The categories of this paper are: oncology
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The categories of this paper are: diseases
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The categories of this paper are: policy
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The categories of this paper are: genomic
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The categories of this paper are: orthopedics
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The categories of this paper are: therapeutics
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The categories of this paper are: dentistry
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The categories of this paper are: endocrinology
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The categories of this paper are: therapy
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The categories of this paper are: quality
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The categories of this paper are: palliative
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The categories of this paper are: nutrition
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The categories of this paper are: pharmacology
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The categories of this paper are: public