Contractile capability of the diaphragm assessed by ultrasonography predicts nocturnal oxygen saturation in COPD.
Diaphragm function might be useful to predict nocturnal oxygen desaturation in COPD. Ultrasonography has been widely used for the assessment of the diaphragm. We aimed to investigate the relationship between the contractile capability of the diaphragm assessed by ultrasonography and the nocturnal percutaneous arterial oxygen saturation (NSpO2) in COPD.



Twenty-eight male patients with COPD (age, 73 ± 7 years; forced expiratory volume in 1 s (FEV1), 54.2 ± 17.0% predicted) were included. The thickness of the diaphragm (Tdi) was assessed by ultrasonography. We calculated the change ratio of Tdi at the end of maximal inspiration and expiration (%ΔTdi). The mean value of NSpO2(NSpO2mean), the percentage of total sleep time (TST) with desaturation above 4% (DA4%) and the percentage of TST with saturation below 90% (SB90%) were measured by overnight oximetry. Daytime arterial oxygen pressure (PaO2) and maximal inspiratory mouth pressure (PImax) were also measured.



All participants had mild or no daytime hypoxaemia (PaO2, 77.3 ± 8.6 mm Hg). The NSpO2mean, DA4% and SB90% were significantly correlated with %ΔTdi, PaO2, %PImaxof the predicted value and the Global Initiative for Chronic Obstructive Lung Disease (GOLD) stage. The %ΔTdi and PaO2were predictors of NSpO2mean by multiple regression analysis.



This study suggested a close relationship between the NSpO2and the contractile capability of the diaphragm assessed by ultrasonography in COPD. The %ΔTdi combined with PaO2might predict NSpO2in COPD patients with mild or no daytime hypoxaemia.
Department of Rehabilitation, Akita City Hospital, Akita, Japan.
Kazuki
K
Okura
Department of Rehabilitation, Akita City Hospital, Akita, Japan.
Atsuyoshi
A
Kawagoshi
Department of Rehabilitation, Akita City Hospital, Akita, Japan.
Masahiro
M
Iwakura
Department of Rehabilitation, Akita City Hospital, Akita, Japan.
Keiyu
K
Sugawara
Department of Rehabilitation, Akita City Hospital, Akita, Japan.
Hitomi
H
Takahashi
Department of Rehabilitation, Akita City Hospital, Akita, Japan.
Takeshi
T
Kashiwagura
Department of Respiratory Medicine, Akita City Hospital, Akita, Japan.
Mitsunobu
M
Homma
Department of Physical Therapy, Akita University Graduate School of Health Sciences, Akita, Japan.
Masahiro
M
Satake
Department of Physical Therapy, Akita University Graduate School of Health Sciences, Akita, Japan.
Takanobu
T
Shioya
D000368:Aged; D000369:Aged, 80 and over; D001784:Blood Gas Analysis; D003964:Diaphragm / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D005541:Forced Expiratory Volume; D006801:Humans; D000860:Hypoxia / Q000097:blood* / Q000209:etiology; D008297:Male; D009119:Muscle Contraction; D010092:Oximetry; D010100:Oxygen / Q000097:blood*; D011237:Predictive Value of Tests; D029424:Pulmonary Disease, Chronic Obstructive / Q000150:complications / Q000503:physiopathology*; D012890:Sleep / Q000502:physiology; D014463:Ultrasonography
D010100:Oxygen
chronic obstructive pulmonary disease; diaphragm; hypoxaemia; sleep; ultrasonography