title: A novel reflex cough testing device.
abstract: The reflex cough test is useful for detecting silent aspiration, a risk factor for aspiration pneumonia. However, assessing the risk of aspiration pneumonia requires measuring not only the cough reflex but also cough strength. Currently, no reflex cough testing device is available that can directly measure reflex cough strength. We therefore developed a new testing device that can easily and simultaneously measure cough strength and the time until the cough reflex, and verified whether screening with this new instrument is feasible for evaluating the risk of aspiration pneumonia.
  
  
  
  This device consists of a special pipe with a double lumen, a nebulizer, and an electronic spirometer. We used a solution of prescription-grade L-tartaric acid to initiate the cough reflex. The solution was inhaled through a mouthpiece as a microaerosol produced by an ultrasonic nebulizer. The peak cough flow (PCF) of the induced cough was measured with the spirometer. The 70 patients who participated in this study comprised 49 patients without a history of pneumonia (group A), 21 patients with a history of pneumonia (group B), and 10 healthy volunteers (control group).
  
  
  
  With the novel device, PCF and time until cough reflex could be measured without adverse effects. The PCF values were 118.3 ± 64.0 L/min, 47.7 ± 38.5 L/min, and 254.9 ± 83.8 L/min in group A, group B, and the control group, respectively. The PCF of group B was significantly lower than that of group A and the control group (p < 0.0001), while that of group B was significantly lower than that of the control group (p < 0.0001). The time until the cough reflex was 4.2 ± 5.9 s, 7.0 ± 7.0 s, and 1 s in group A, group B, and the control group, respectively. This duration was significantly longer for groups A and B than for the control group (A: p < 0.001, B: p < 0.001), but there was no significant difference between groups A and B (p = 0.0907).
  
  
  
  Our newly developed device can easily and simultaneously measure the time until the cough reflex and the strength of involuntary coughs for assessment of patients at risk of aspiration pneumonia.
authors.affiliation: Department of Otolaryngology, Head and Neck Surgery, Faculty of Medicine, Tottori University, 36-1, Nishimachi, Yonago, 683-8504, Japan. kfujiwa@med.tottori-u.ac.jp.
authors.forename: Kazunori
authors.initials: K
authors.lastname: Fujiwara
authors.affiliation: Department of Otolaryngology, Head and Neck Surgery, Faculty of Medicine, Tottori University, 36-1, Nishimachi, Yonago, 683-8504, Japan.
authors.forename: Katsuyuki
authors.initials: K
authors.lastname: Kawamoto
authors.affiliation: Department of Rehabilitation, Tottori University Hospital, 36-1, Nishimachi, Yonago, 683-8504, Japan.
authors.forename: Yoko
authors.initials: Y
authors.lastname: Shimizu
authors.affiliation: Department of Otolaryngology, Head and Neck Surgery, Faculty of Medicine, Tottori University, 36-1, Nishimachi, Yonago, 683-8504, Japan.
authors.forename: Takahiro
authors.initials: T
authors.lastname: Fukuhara
authors.affiliation: Department of Otolaryngology, Head and Neck Surgery, Faculty of Medicine, Tottori University, 36-1, Nishimachi, Yonago, 683-8504, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Koyama
authors.affiliation: Department of Otolaryngology, Head and Neck Surgery, Faculty of Medicine, Tottori University, 36-1, Nishimachi, Yonago, 683-8504, Japan.
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Kataoka
authors.affiliation: Department of Otolaryngology, Head and Neck Surgery, Faculty of Medicine, Tottori University, 36-1, Nishimachi, Yonago, 683-8504, Japan.
authors.forename: Hiroya
authors.initials: H
authors.lastname: Kitano
authors.affiliation: Department of Otolaryngology, Head and Neck Surgery, Faculty of Medicine, Tottori University, 36-1, Nishimachi, Yonago, 683-8504, Japan.
authors.forename: Hiromi
authors.initials: H
authors.lastname: Takeuchi
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001985:Bronchial Provocation Tests / Q000295:instrumentation*; D016022:Case-Control Studies; D003371:Cough / Q000139:chemically induced / Q000209:etiology*; D005260:Female; D005540:Forced Expiratory Flow Rates; D006801:Humans; D007564:Japan; D008297:Male; D008875:Middle Aged; D011015:Pneumonia, Aspiration / Q000175:diagnosis*; D012018:Reflex; D013644:Tartrates / Q000008:administration & dosage*
chemical_list: D013644:Tartrates; C029768:tartaric acid
keywords: Aspiration pneumonia; Involuntary cough; Peak cough flow; Reflex cough test; Silent aspiration