Chest
Original ResearchCritical CareDiaphragm Muscle Thinning in Patients Who Are Mechanically Ventilated
Section snippets
Subjects
The St. Luke's-Roosevelt Hospital Institutional Review Board approved this study and designated it study number 09-222. We randomly selected seven newly intubated patients (within 24 h) from the ED, ICU, or medical ward. Patients with tracheostomies were excluded. Informed consent was obtained from the patient or his/her health-care proxy. The patient's chart was reviewed for demographic information and clinical data. Serial ultrasonographic measurements of diaphragm thickness were performed
Results
Overall, the average diaphragm thickness in this group decreased significantly over time at a rate of 6% per day on MV. Similarly, the diaphragm thickness in each patient decreased over time (fig 2). Measurements of diaphragm thickness were taken successfully at end-expiration in all patients. In the group, initial diaphragmatic thickness correlates with weight in kilograms (Pearson correlation coefficient = 0.76, P = .046) (Fig 3).
Linear mixed models revealed that the duration of MV
Discussion
Diaphragm muscle strength has been demonstrated using functional, physiologic, and anatomic methods. Functional measurement includes inspiratory and expiratory pressure differences generated by patients breathing against a closed valve; however, this measurement is effort dependent and poorly reproducible, particularly in intubated, critically ill patients. Esophageal and gastric balloons with pressure transducers can also be used to calculate transdiaphragmatic pressures by subtracting the
Conclusions
We conclude from this study that measured thinning of the diaphragm occurs within 48 h after intubation and the initiation of MV, most consistent with MV-related atrophy. Ultrasound is an easily applied technology in this setting. Further studies are needed to evaluate if this uniform decrease in diaphragm thickness is indeed due to diaphragm atrophy, and if this has an impact on the discontinuation of MV. Larger studies are needed to clarify the relationship between diaphragmatic thinning and
Acknowledgments
Author contributions: Drs J. Lee and Rose had full access to the study data and can vouch for the study integrity and data analysis.
Dr Grosu: contributed to the identification of the purpose of the study, data collection and management, and the writing and revising of the manuscript.
Dr Y. I. Lee: contributed to the creation of the data collection instrument, data collection and management, the creation of the table, and the writing of the manuscript.
Dr J. Lee: contributed to the study design,
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Funding/Support: The authors have reported to CHEST that no funding was received for this study.
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