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)