Abstract
Objective
The purpose of this study was to investigate whether changes in breathing pattern, neuromuscular drive (P0.1), and the work involved in breathing might help to set the individual appropriate level of pressure support ventilation (PSV) in patients with acute respiratory failure (ARF) requiring ventilatory assistance.Design: A prospective, interventional study.
Setting
An 8-bed multidisciplinary intensive care unit (ICU).
Patients
Ten patients with ARF due to adult respiratory distress syndrome (ARDS), sepsis or airway infection were included in the study. Chronic obstructive pulmonary disease (COPD) patients with acute exacerbation were excluded. None of these patients was in the weaning process.
Interventions
We found a level of pressure support able to generate a condition of near-relaxation in each patient, as evidenced by work of breathing (WOB) values close to 0 J/l. This level was called PS 100 and baseline physiological measurements, namely, breathing pattern, P 0.1 and WOB were obtained. Pressure support was then reduced to 85%, 70% and 50% of the initial value and the same set of measurements was obtained.
Measurements and results
Flow (\(\dot V\)) was measured by a flow sensor (Varflex) positioned between the Y-piece of the breathing circuit and the endotracheal tube. Tidal volume was obtained by numerical integration of the flow signal. Airway pressure (Paw) was sampled through a catheter attached to the flow sensor. Esophageal pressure (Pes) was measured with a nasogastric tube incorporating an esophageal balloon. The esophageal balloon and flow and pressure sensors were connected to a portable monitor (CP 100 Bicore) that provided realtime display of flow, volume, Paw and Pes tracings and loops of Pes/V, Paw/V and\(\dot V\)/V relationships. The breathing pattern was analyzed from the flow signal. Patient work of breathing (WOB) was calculated by integration of the area of the Pes/V loop. Respiratory drive (P 0.1) was measured at the esophageal pressure change during the first 100 ms of a breath, by the quasiocclusion technique. When pressure support was reduced, we found that the respiration rate significantly increased from PS 100 to PS85, but varied negligibly with lower pressure support levels. Tidal volume behaved in a similar way, decreasing significantly from PS 100 to PS85, but hardly changing at PS 70 and PS 50. In contrast, WOB and P 0.1 increased progressively with decreasing pressure support levels. The changes in WOB were significant at each stage in the trial, whereas P 0.1 increased significantly from PS 100 at other stages. Linear regression analysis revealed a highly positive, significant correlation between WOB and P 0.1 at decreasing PSV levels (r=0.87), whereas the correlation between WOB and ventilatory frequency was less significant (r=0.53). No other correlation was found.
Conclusions
During pressure support ventilation, P 0.1 may be a more sensitive parameter than the assessment of breathing pattern in setting the optimal level of pressure support in individual patients. Although P 0.1 was measured with an esophageal balloon in the present study, non-invasive techniques can also be used.
Article PDF
Similar content being viewed by others
References
McIntyre NR (1986) Respiratory function during pressure support ventilation. Chest 89:677–683
Fargier JJ, Robert D, Boyer F et al (1987) Positive pressure inspiratory aid vs assisted mechanical ventilation after esophageal surgery. J Crit Care 2: 101–108
Brochard L (1991) Pressure support ventilation. In: Marini JJ, Roussos C (eds) Ventilatory failure. Springer, Berlin Heidelberg New York, pp 381–391
Campbell RS, Branson RD (1993) Ventilatory support for the 90s: pressure support ventilation Respir Care 38: 526–537
McIntyre NR, Leatherman NE (1990) Ventilatory muscle loads and the frequency-tidal volume pattern during inspiratory pressure-assisted (pressure-supported) ventilation. Am Rev Respir Dis 141:327–331
Brochard L, Harf A, Lorino H, Lemaire F (1989) Inspiratory pressure support prevents diaphragmatic fatigue during weaning from mechanical ventilation. Am Rev Respir Dis 139: 513–521
Ershowsky P, Krieger B (1987) Changes in breathing pattern during pressure support ventilation. Respir Care 32:1011–1016
Ishaaya A, Nathan S, Koerner S, Belman M (1992) Accuracy of work of breathing prediction with pressure support ventilation during weaning. Am Rev Respir Dis 145:A 518
Banner MJ, Kirby RR, Blanch PB, Layon AJ (1992) Decreasing patient work of breathing using pressure support ventilation to unload the ventilatory muscles. Crit Care Med 20:S68
Baydur A, Behrakis PK, Zin WA, Jaeger M, Milic-Emili J (1982) A simple method for assessing the validity of the esophageal balloon technique. Am Rev Respir Dis 126:788–791
Nathan SD, Ishaaya AM, Koerner SK, Belman MJ (1993) Prediction of minimal pressure support during weaning from mechanical ventilation. Chest 103:1215–1219
Otis AB (1964) The work of breathing. In: Fenn WO, Rahn H (eds) Handbook of physiology. American Physiological Society, Washington, DC, pp 463–476
Taylor RF, Marini JJ, Smith TC et al (1987) Bedside estimation of respiratory drive during machine-assisted ventilation. Am Rev Respir Dis 135:A51
Dal Vecchio L, Polese G, Poggi R, Rossi A (1990) Intrinsic positive end-expiratory pressure in stable patients with chronic obstructive pulmonary disease. Eur Respir J 3:74–80
Tokioka H, Saito S, Kosaka F (1989) Effect of pressure support ventilation on breathing pattern and respiratory work. Intensive Care Med 15:491–494
Kakmarek RM (1988) The role of pressure support ventilation in reducing work of breathing. Respir Care 33: 39–120
Brochard L, Pluskwa F, Lemaire F (1987) Improved efficacy of spontaneous breathing with inspiratory pressure support. Am Rev Respir Dis 136: 411–415
Marini JJ (1987) The role of the inspiratory circuit in the work of breathing during mechanical ventilation. Respir Care 32:419–430
Whitelaw W, Derenne JP, Milic-Emili J (1982) Occlusion pressure as a measure of respiratory center output in conscious man. Respir Physiol 23:181–199
Kakmarek RM (1989) Inspiratory pressure support: does it make a clinical difference? Intensive Care Med 15: 337–339
Henning RJ, Shubin H, Weil MH (1977) The measurement of the work of breathing for the clinical assessment of ventilatory dependence. Crit Care Med 5:264–268
Bersten AD, Rutten AJ, Vedig AE, Skowronski GA (1989) Additional work of breathing imposed by endotracheal tubes, breathing circuits, and intensive care ventilators. Crit Care Med 17: 671–677
Fiastro JF, Habib MP, Quan SF (1988) Pressure support compensation for inspiratory work due to endotracheal tubes and demand continuous positive airway pressure. Chest 93:499–505
Viale JP, Annat GJ, Bouffard YM, Delafosse BX, Bertrand OH, Motin JP (1988) Oxygen cost of breathing in postoperative patients. Chest 93: 506–509
Annat GJ, Viale JP, Dereymez CP, Bouffard YM, Delafosse BX, Motin JP (1990) Oxygen cost of breathing and diaphragmatic pressure time-index. Measurement in patients with COPD during weaning with pressure support ventilation. Chest 98:411–414
Tokioka H, Saito S, Kosaka F (1989) Comparison of pressure support ventilation and assist control ventilation in patients with acute respiratory failure. Intensive Care Med 15:364–367
Sahn SA, Lakshminarayan S, Petty TL (1976) Weaning from mechanical ventilation. JAMA 235:2208–2212
Boyer F, Bruneau B, Gaussorgues P, Jay-Lassonnery S, Robert D (1989) Aide inspiratoire avec asservissement du niveau de pression: volume ventilé minute versus fréquence ventilatoire. Rean Soins Intens Med Urg 5:227–232
Amato MPB, Barbas CSV, Bonassa J, Saldiva PHN, Zin WA, Ribeiro de Carvalho CR (1992) Volume-assured pressure support ventilation (VAPSV). A new approach for reducing muscle workload during acute respiratory failure. Chest 102:1225–1234
Sassoon CSH, Te TT, Mahutte CK, Light RW (1987) Airway occlusion pressure. An important indicator for successful weaning in patients with chronic obstructive pulmonary disease. Am Rev Respir Dis 135:107–113
Murciano D, Boczkowski J, Lecocguic Y, Milic-Emili J, Pariente R, Aubier M (1988) Tracheal occlusion pressure: a simple index to monitor respiratory muscle fatigue during acute respiratory failure in patients with chronic obstructive pulmonary disease. Ann Intern Med 108:800–805
Herrera M, Blasco J, Venegas J, Barba R, Dablos A, Marquez E (1985) Mouth occlusion pressure (P 0.1) in acute respiratory failure. Intensive Care Med 11:134–139
Marini JJ, Rodriguez M, Lamb V (1986) The inspiratory workload of patient-initiated mechanical ventilation. Am Rev Respir Dis 134:902–909
Fernandez R (1991) Inspiratory occluded airway pressure. In: Benito S, Net A (eds) Pulmonary function in mechanically ventilated patients. Springer, Berlin Heidelberg New York, pp 39–51
Marini JJ (1990) Strategies to minimize breathing effort during mechanical ventilation. Crit Care Clin 6:635–661
Marazzini L, Cavestri R, Gori D, Gatti L, Longhini E (1978) Difference between mouth and esophageal occlusion pressure during CO2 rebreathing in chronic obstructive pulmonary disease. Am Rev Respir Dis 118:1027–1033
Murciano D, Aubier M, Bussi S, Derenne JP, Pariente R, Milic Emili J (1982) Comparison of esophageal, tracheal and mouth occlusion pressure in patients with chronic obstructive pulmonary disease during acute respiratory failure. Am Rev Respir Dis 126:837–841
Whitelaw WA, Derenne JP (1993) Airway occlusion pressure. J Appl Physiol 74:1475–1483
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Alberti, A., Gallo, F., Fongaro, A. et al. P0.1 is a useful parameter in setting the level of pressure support ventilation. Intensive Care Med 21, 547–553 (1995). https://doi.org/10.1007/BF01700158
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF01700158