Objective
To define the effect of the inspiratory method and cough timing on peak cough flow (PCF).
Methods
We investigated the effect of measurement conditions on PCF in healthy subjects (n=10). We then compared obstructive and restrictive pulmonary diseases (n=20) to assess for similar results in respiratory diseases. The PCF was measured under four conditions: before coughing, without maneuver 1 or with maneuver 2 a temporary respiratory pause (4–6 seconds) after rapid inspiration, and without maneuver 3 or with maneuver 4 a temporary respiratory pause after slow inspiration. After the measurements were completed, the PCF between the four conditions was compared for each subject group, and the effect size was calculated.
Results
PCF of maneuvers 1 and 3 were significantly higher than maneuver 4 in healthy subjects (476.34±102.05 L/min and 463.44±107.14 L/min vs. 429.54±116.83 L/min, p<0.01 and p<0.05, respectively) and patients with restrictive pulmonary disease (381.96±145.31 L/min, 354.60±157.36 L/min vs. 296.94±137.49 L/min, p<0.01 and p<0.05, respectively). In obstructive pulmonary disease, maneuver 1 was significantly higher than maneuver 4 (327.42±154.73 L/min vs. 279.48±141.10 L/min, p<0.05). The largest effect sizes were shown by maneuvers 4 and 1.
Conclusion
PCF depends on changes in inspiratory speed before coughing and on temporary respiratory pauses after maximal inspiration. It will become necessary to unify the measurement methods for coughing strength and present appropriate coughing methods.

Citations

• Factors related to pre-operative cough strength in cardiac surgical patients: a cross-sectional study
  Yan Zhang, Zheng Lin, Yuhong Chen, Liang Hong, Xiao Shen
  Heart & Lung.2024; 63: 128.     CrossRef

Objective
To investigate and demonstrate persistent increase of peak cough flow after mechanical in-exsufflator application, in patients with neuromuscular diseases and pneumonia.
Methods
A mechanical in-exsufflator was applied with patients in an upright or semi-upright sitting position (pressure setting, +40 and −40 cmH2O; in-exsufflation times, 2–3 and 1–2 seconds, respectively). Patients underwent five cycles, with 20–30 second intervals to prevent hyperventilation. Peak cough flow without and with assistive maneuvers, was evaluated before, and 15 and 45 minutes after mechanical in-exsufflator application.
Results
Peak cough flow was 92.6 L/min at baseline, and 100.4 and 100.7 L/min at 15 and 45 minutes after mechanical in-exsufflator application, respectively. Assisted peak cough flow at baseline, 15 minutes, and 45 minutes after mechanical in-exsufflator application was 170.7, 179.3, and 184.1 L/min, respectively. While peak cough flow and assisted peak cough flow increased significantly at 15 minutes after mechanical in-exsufflator application compared with baseline (p=0.030 and p=0.016), no statistical difference was observed between 15 and 45 minutes.
Conclusion
Increased peak cough flow after mechanical in-exsufflator application persists for at least 45 minutes.

Citations

• Pearls and pitfalls of respiratory testing in a patient with amyotrophic lateral sclerosis and COPD
  Stephen W. Littleton, Franco Laghi
  Breathe.2023; 19(2): 230043.     CrossRef
• The use of cough peak flow in the assessment of respiratory function in clinical practice- A narrative literature review
  M. Brennan, M.J. McDonnell, N. Duignan, F. Gargoum, R.M. Rutherford
  Respiratory Medicine.2022; 193: 106740.     CrossRef
• Comparison of two mechanical insufflation-exsufflation devices in patients with amyotrophic lateral sclerosis: a preliminary study
  Antonello NICOLINI, Paola PRATO, Laura BECCARELLI, Bruna GRECCHI, Giancarlo GARUTI, Paolo BANFI, Francesco D’ABROSCA
  Panminerva Medica.2022;[Epub]     CrossRef
• Analysis of Pneumothorax in Noninvasive Ventilator Users With Duchenne Muscular Dystrophy
  Han Eol Cho, Justin Byun, Won Ah Choi, Myungsang Kim, Kyeong Yeol Kim, Seong-Woong Kang
  Chest.2021; 159(4): 1540.     CrossRef

Objective
To evaluate the effect of the air stacking exercise on maximal insufflation capacity (MIC) and peak cough flow (PCF) in patients with neuromuscular diseases. Method: Two hundred twenty nine neuromuscular patients with vital capacity (VC) below 50% of the predicted normal value were initially evaluated for VC, MIC, PCF, and assisted PCF (APCF). After the first evaluation, these patients were instructed to carry out air stacking exercise periodically, and were re-evaluated after one year. Results: Forty seven patients were capable of performing air stacking exercise on regular basis, at least twice a day for one year. Among these patients, MIC increased in 28 patients from 1345.4 ml to 1572.9 ml on average (p＜0.05), while it decreased in 19 patients from 1740.0 ml to 1325.3 ml on average (p＜0.05). In the increasing MIC group APCF increased from 244.6 L/min to 278.1 L/min (p＜ 0.05). In the decreasing MIC group, every value decreased significantly. Conclusion: Air stacking exercise was shown to be capable of increasing MIC and APCF despite the reduction in VC and PCF in patients with neuromuscular diseases. (J Korean Acad Rehab Med 2007; 31: 346-350)

Objective
The patients with glottic dysfunction cannot cough effectively. It is difficult to eliminate pulmonary secretions and to provide lung expansion exercise in those patients. Thus we made a device which substitutes the function of glottis and examines the effectiveness of the external glottic function of the device. Method: This new device was made of two parts: connection and control part. Connection part had three ports: patient connection, insufflation and connection port. The insufflation port with one-way valve allows additional air stacking using a manual resuscitation bag after a patients's deep inspiration. Control part had external glottic function by air flow control with button pushing simply. The vital capacity (VC), maximal insufflation capacity (MIC), MIC with device (MICdevice), unassistive peak cough flow (UPCF), assistive peak cough flow (APCF) and assistive peak cough flow with device (APCFdevice) were measured in six patients. Results: In tested patients, four were amyotrophic lateral sclerosis patients and two were cervical spinal cord injury patients with tracheostomized. The value of MICdevice or APCFdevice was higher than MIC or APCF in all patients. Conclusion: This new device can improve the bronchial toileting by improving cough function and also provide lung expansion exercise effectively in patients with glottic dysfunction. (J Korean Acad Rehab Med 2005; 29: 219-224)

Objective
To investigate the pathologic pulmonary mechanics and analyze the factors affecting cough ability in patients with Duchenne muscular dystrophy (DMD).

Method: Thirty-one patients with DMD were investigated. The vital capacity (VC), maximum insufflation capacity (MIC), maximal inspiratory (MIP), and expiratory pressure (MEP) were measured. Unassisted peak cough flow (UPCF) and assisted PCF at three different conditions were evaluated.

Results: The mean value of MICs (1,873⁑644 cc) was higher than that of VCs (1,509⁑640 cc). MIP and MEP were 48.8⁑21.4% and 29.5⁑19.5% of predicted normal value respectively. MIP was correlated with UPCFs as well as MEP. All of three assisted cough methods showed significantly higher value than unassisted method (p＜0.01). The manual assisted PCFs at MIC significantly exceeded those produced by manual assisted or PCFs at MIC. The positive correlation between the MIC-VC difference and PCF at MIC-UPCF difference was seen (p＜0.01).

Conclusion: Inspiratory muscle strength and the preservation of pulmonary compliance is important for the development of effective cough as well as expiratory muscle power. Thus, the clinical implication of the inspiratory phase in assisting a cough should be emphasized. (J Korean Acad Rehab Med 2003; 27: 43-48)

Objective
To analyze the factors influencing the capacity of cough, the relationships between maximal respiratory pressure, lung compliance, capacity of cough, and assisted cough techniques were evaluated in tetraplegics. Method: The vital capacity (VC) in seated and supine position, maximum insufflation capacity (MIC), maximum inspiratory (MIP) and expiratory (MEP) pressure in seated position were measured. Unassisted and assisted peak cough flow (PCF) at two different conditions (a volume assisted method by the mechanical insufflation [PCFmic] and the manual assistance by abdominal compression [MPCF]) were evaluated in 44 tetraplegic patients. Results: The mean value of VC in supine was greater than that of seated position (p＜0.01). The MICs of the subjects were significantly higher than VCs in a same position (＜0.01). Both volume and manual assisted method showed significantly higher PCF than unassisted PCF (p＜0.01). MIP (r=0.53) correlated with UPCF as well as MEP (r=0.68), although MEP was better correlated with MPCF. Conclusion: Generally the therapists apply manual pressure only to increase capacity of cough, which assist the expulsive phase. The results of this study showed that both inspiratory and expulsive phases should be assisted to enhance the effectiveness of cough. (J Korean Acad Rehab Med 2002; 26: 704-708)