Nasal CPAP, Abdominal muscles, Posture, Diagnostic ultrasound, Electromyogram

Transcription

1 Nasal CPAP, Abdominal muscles, Posture, Diagnostic ultrasound, Electromyogram

2 Fig. 1 EMG recordings of activity of four abdominal muscles in a subject on continuous positive airway pressure in supine and standing positions. RA : rectus abdominis, EO : external oblique, IO: internal oblique, TA: transversus abdominis. CPAP : continuous positive airway pressure. Insp : inspiration, SUPINE Exp : expiration. STANDING Table 1 Electrical activity of individual abdominal muscles. RA : rectus abdominis, EO : external oblique, IO: internal oblique, TA : transversus abdominis. Fractions indicate the rate of appearance of expiratory electromyographic activity in six subjects.

3 Fig. 3 Electrical activity of the external oblique. Value at "A" is different (p<0.01) from the mean value at OcmH2O CPAP. Comparison was made for the same position. Other conventions as in Fig. 2. CPAP (cmh2o) CPAP (cmh2o) Fig. 2 Electrical activity of the rectus abdominis. Electrical activity is expressed in arbitrary units (A.U.). EMG : electromyographic activity. CPAP : continuous positive airway pressure. Solid bars. mean values while supine. Open bars: mean values while standing. Error bars. standard deviations. Fig. 4 Electrical activity of the internal oblique. Values at : "A"s are different (p<0.01) from the mean value at OcmH2O CPAP, "B" is different (p<0.01) from the mean value at 5cmH2O CPAP, "b" is different (p<0.05) from the mean value at 5cmH2O CPAP. "c" is different (p< 0.05) from the mean value at locmh2o CPAP. Comparisons made in the same position. Other conventions as in Fig. 2.

4 Fig. 5 Electrical activity of the transverses abdominis. Value at "A" is different (p<0.01) from the mean value at OcmH2O CPAP, "B" is different (p- 0.01) from the mean value at 5cmH2O CPAP. Comparisons made in the same position. Other conventions as in Fig. 2.

5 References 1) Gray's Anatomy : The Muscles of the abdomen. 35th, Ed. by Warwick R. & Williams, P.L., p. 519, Longman, Edinburgh, ) Loring, S.H. & De Troyer, A.: Actions of the respiratory muscles. In : "The Thorax" (Lung biology in health and disease ; v. 29) Ed. by Roussos, C. & Macklem, P.T., p. 327, Marcel Dekker, Inc., New York, ) Goldman, J.M., Lehr, R.P., Millar, A.B. & Silver, J.R.: An electromyographic study of the abdominal muscles during postural and respiratory manoeuvres. J. Neurol. Neurosurg. Psychiatry., 50: 866, ) De Troyer, A., Estenne, M., Ninane, V., Van Gansbeke, D. & Gorini, M.: Transversus abdominis muscle function in humans. J. Appl. Physiol., 68: 1010, ) Basmajian, J.V. & Stecko, G.: A new bipolar electrode for electromyography. J. Appl. Physiol., 17: 849, 1962.

6 6) Carman, D.J., Blanton, P.L. & Biggs, N.L.: Electromyographic study of the anterolateral abdominal musculature utilizing indwelling electrodes. Am. J. Phys. Med., 51: 113, ) De Troyer, A.: Mechanical role of the abdominal muscles in relation to posture. Respir. Physiol., 53: 341, ) Strohl, K.P., Mead, J., Banzett, R.B., Loring, S. H. & Kosch,P.C.: Regional differences in abdominal muscle activity during various maneuvers in humans. J. Appl. Physiol., 51: 1471, ) Druz, W.S. & Sharp, J.T.: Activity of respiratory muscles in upright and recumbent humans. J. Appl. Physiol., 51: 1552, ) Wakai, Y., Welsh, M.M., Leevers, A.M. & Road, J.D.: Expiratory muscle activity in the awake and sleeping human during lung inflation and hypercapnia. J. Appl. Physiol., 72: 881, ) Ninane, V., Rypens, F., Yernault, J.C. & De Troyer, A.: Abdominal muscle use during breathing in patients with chronic airflow obstruction. Am. Rev. Respir. Dis.,146 :16, ) Duomarco, J.L. & Rimini, R.: (1947). La presion intraabdominal en el hombre. Buenos Aires, El Ateneo. Cited in Agostoni, E. & Rahn, H.: Abdominal and thoracic pressures at different lung volumes. J. Appl. Physiol., 15: 1087, ) Estenne, M., Ninane, V. & De Troyer, A.: Triangularis sterni muscle use during eupnea in humans : Effect of posture. Respir. Physiol., 74: 151, ) Road, J.D. & Leevers, A.M.: Effect of lung inflation on diaphragmatic shortening. J. Appl. Physiol., 65: 2383, ) Newman, S.L., Road, J.D. & Grassino, A.: In vivo length and shortening of canine diaphragm with body postural change. J. Appl. Physiol., 60: 661, ) Loring, S.H. & Mead, J.: Abdominal muscle use during quiet breathing and hyperpnea in uninformed subjects. J. Appl. Physiol., 52: 700, ) Bishop, B.: Reflex control of abdominal muscles during positive-pressure breathing. J. Appl. Physiol., 19: 224, ) Russel, J.A., Bishop, P.B. & Hyatt, R.E.: Discharge of abdominal ci and y motoneurons during expiratory loading in cats. Exp. Neurol., 97: 179, ) Agostoni, E. & Hyatt, R.E.: Static behaviorof the respiratory system, edited by Fishman, A.P., Handbook of physiology section 3 : The respiratory system vol 3 part 1, volume editors Macklem, P.T. & Mead, J., Executive Editor Geiger SR. American Physiological Society. Maryland. 1986, p ) Davis, A., Sant'Ambrogio, F.B. & Sant'Ambrogio, G.: Control of postural changes of end expiratory volume (FRC) by airways slowly adapting mechanoreceptors. Respir. Physiol., 41: 211, 1980.

7 16 Abstract Response of Individual Abdominal Muscles to Nasal CPAP in Supine and Standing Positions in Humans Naotaka Yoshimura, Tadashi Abe and Tomoyuki Tomita Department of Medicine, School of Medicine, Kitasato University Kitasato, Sagamihara, Kanagawa 228, Japan The respiratory function of individual abdominal muscles in humans is not well known. Some workers have reported that abdominal muscles act as a single unit during breathing, whereas others have reproted differential activation. In the present study, fine wire electrodes were inserted into the rectus abdominis (RA), external oblique (EO), internaloblique (IO), and transversus abdominis (TA) muscles in six healthy awake subjects under direct vision provided by high-resolution ultrasonography. Electromyographic (EMG) signals were then recorded in thesupine and standing positions during resting ventilation without nasal continuous positive airway pressure (ncpap), then on ncpap at 5,10,15, and20 cmh2o. Peak values of integrated EMG during expirationwere measured. For each abdominal muscle,the number of subjects showing expiratory EMG activity increased with increasing ncpap or with a change in posture from supine to standing or both. The number of subjects showing expiratory abdominalmuscle activity under any condition followed the order: RA EO IO TA. Peak expiratory EMG activity increased significantly with increasing ncpap in the standing position for EO (p<0.05), and in both positions for IO and TA (both p <0.01). These results suggest that: 1) both the standing position and ncpap imposed an expiratory load, 2) TA and IO are most sensitive to expiratory loading, and are the primary expiratory muscles, and 3) RA is least sensitive to expiratory loading, and is a secondary expiratory muscle. We conclude that individual abdominal muscles respond differently to expiratory loading.