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Research Article
Postural Change of FVC in Patients with Neuromuscular Disease: Relation to Initiating Non-Invasive Ventilation
Joe Chen1, Nathan Nguyen2, Matt Soong2 and Ahmet Baydur1*1Divisions of Pulmonary and Critical Care Medicine, Keck School of Medicine, University of Southern California, USA
2Divisions of General Medicine, Keck School of Medicine, University of Southern California, USA
- *Corresponding Author:
- Baydur A
Division of Pulmonary and Critical Care Medicine
Keck School of Medicine, University of Southern California
IRD 723, 2020 Zonal Avenue, Los Angeles, CA 90033, USA
E-mail: [email protected]
Received date: April 04, 2013; Accepted date: May 06, 2013; Published date: May 08, 2013
Citation: Chen J, Nguyen N, Soong M, Baydur A (2013) Postural Change of FVC in Patients with Neuromuscular Disease: Relation to Initiating Non-Invasive Ventilation. J Pulmon Resp Med 3:147 doi: 10.4172/2161-105X.1000147
Copyright: © 2013 Chen J, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Abstract
Background: Forced Vital Capacity (FVC) has been used to assess respiratory muscle strength in patients with Neuromuscular Disease (NMD). However, postural changes to FVC have not been assessed in relation to the start of Non-Invasive Ventilation (NIV). This study aims to assess the changes to postural FVC for indications of NIV.
Methods: The records of spirometry performed in seated and supine posture were retrospectively reviewed in 33 patients with NMD [18 breathing spontaneously (SB), 15 receiving NIV]. The change in FVC (in L) between seated (sit) and supine (sup) positions was expressed as %⊗ FVC (sit – sup) = [{FVC(L)sit – FVC(L)sup}/FVC(L)sit]. The postural change in forced expiratory flow (FEF), % FEF (sit – sup) was similarly computed.
Results: %ΔFVC (sit – sup) in patients receiving NIV exceeded the %ΔFVC (sit – sup) of SB patients by 14-fold (p = 0.001). %ΔFEF (sit–sup) however, did not reach statistical significance between cohorts. There was a negative correlation between %ΔFVC (sit-sup) and FVCsit(% pred) (R = -0.40, p = 0.02), and a direct correlation between %ΔFVC(sit-sup) and %ΔFEF(sit-sup) (R = 0.72, p<0.0001) amongst all patients.
Conclusions: Postural change of FVC in patients with neuromuscular disease placed on noninvasive ventilation is significantly greater than in those still able to breathe spontaneously. A prospective longitudinal study designed to assess the predictive value of ΔFVC (sit – sup), and if possible, a threshold value for initiating NIV may provide a guideline more precise than the seated FVC.
