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Laboratory and Animal InvestigationsShort-Duration Mechanical Ventilation Enhances Diaphragmatic Fatigue Resistance but Impairs Force Production
Section snippets
Experimental Animals and Research Design
These experiments were approved by the University of Florida animal use committee, and followed the guidelines for animal experiments established by the National Institutes of Health. Healthy, female, young adult (4-month-old) Sprague-Dawley rats were individually housed, fed rat chow and water ad libitum, and were maintained on a 12-h light/dark cycle for 3 weeks prior to initiation of these experiments. Animals were randomly assigned to one of two experimental groups: control animals (n = 8)
Systemic and Biological Response to MV
No animals were eliminated due to infection. However, one animal from the MV group was eliminated from our analysis because the postmortem examination revealed evidence of lung barotrauma. Of the animals included in our analysis, initial and final body weights did not differ (p > 0.05) between control animals and MV-treated animals. Importantly, 18 h of MV did not result in a significant change (p > 0.05) in animal body weight (data not shown). These results indicate that our schedule of
Overview of Principle Findings
Although previous experiments have reported that relatively short-duration MV results in diaphragmatic force deficits, the present experiments provide important new information regarding the influence of controlled MV on diaphragmatic endurance. Our results support the hypothesis that 18 h of MV results in a significant reduction (approximately 20%) in diaphragmatic specific Po. Furthermore, these data support the notion that 18 h of MV does not accelerate the rate of diaphragmatic fatigue
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The possible predictive value of muscle ultrasound in the diagnosis of ICUAW in long-term critically ill patients
2022, Journal of Critical CareCitation Excerpt :Even though we considered only a long-term cohort of patients, our findings are similar to other reports that estimated an incidence of ICUAW of 30%–90% depending on the method and time of diagnosis [35,36]. Recent preclinical and clinical studies have suggested diaphragmatic involvement, including reduced muscle force and increased muscle atrophy [14,37-39]. Interestingly, a preliminary study in humans suggested that even short-term diaphragmatic inactivity imposed by controlled mechanical ventilation could result in marked diaphragmatic atrophy [40].
Mechanical ventilation induces diaphragmatic mitochondrial dysfunction and increased oxidant production
2009, Free Radical Biology and MedicineHypoventilation and Respiratory Muscle Dysfunction
2008, Critical Care Medicine: Principles of Diagnosis and Management in the AdultMechanostimulation, electrostimulation and force measurement in an in vitro model of the isolated rat diaphragm
2011, Physiological MeasurementMitochondria-targeted antioxidants protect against mechanical ventilation-induced diaphragm weakness
2011, Critical Care MedicineN-Acetylcysteine protects the rat diaphragm from the decreased contractility associated with controlled mechanical ventilation
2011, Critical Care MedicineCitation Excerpt :Concerning the antioxidant properties of NAC, we measured protein carbonyls as a marker of protein oxidation. Our results showed that CMV resulted in increased levels of protein oxidation in the diaphragm, which is consistent with the increase in oxidative stress during CMV reported in previous studies (11, 13, 40). Oxidative stress in the diaphragm during CMV is important because it can contribute to VIDD.
This work was supported by grants from the American Lung Association-Florida and the National Institutes of Health (R01 HL62361) awarded to Dr. Powers.