INTRODUCTION: maximum inspiratory (PImax) and expiratory (PEmax) pressures are a simple non-invasive method for evaluation of respiratory muscle strength that helps in the identification of muscle weakness, usually present in several diseases and clinical situations, such as quadriplegia. Objective: to assess the number of maneuvers needed to achieve maximum pressures in patients with quadriplegia. METHODS: eight quadriplegic patients (seven men) with mean age range of 37.8±11.96 years old and diagnosed with complete spinal cord lesion were submitted to ten measurements of PImax and PEmax in both seated and supine positions, totalizing 320 measurements. Data were compared by using the Wilcoxon's test (p<0.05). RESULTS: the 1st and 10th measurements of PImax and PEmax for seated position ranged from 74.1±15.1 to 74.8±19.8 cmH2O and 32.4±6.8 to 32.4±9.0 cmH2O, respectively; whereas for supine position these measurements ranged from 76.5±18.6 to 91.1±13.3 cmH2O (p<0.05) and 32.5±5.8 to 32.9±5.1 cmH2O, respectively. The results regarding the 3rd and 5th measurements of PImax for seated position were 81.1±19.5 cmH2O, 81.5±18.8 cmH2O, and 83.0±18.9 cmH2O; whereas PEmax had 35.0±8.2 cmH2O; 35.3±7.9 cmH2O, and 36.8±8.0 cmH2O. PImax values for seated position were 90.3±17.8 cmH2O, 94.6±16.0 cmH2O, and 97.4±17.8 cmH2O (p<0.05), whereas PEmax resulted in 33.3±5.8 cmH2O, 35.6±5.4 cmH2O, and 36.9±4.9 cmH2O). The highest value occurred from the sixth measurement in 40% of the tests. CONCLUSION: as to obtain maximum values for respiratory pressures in quadriplegic patients, it is necessary to repeat each measurement at least ten times.
Quadriplegia; Respiratory muscles; Muscle strength; Evaluation; Manometry
