Download PDF

Canadian Anaesthetists’ Society Journal

, Volume 27, Issue 2, pp 89–95 | Cite as

Oxygen consumption during spontaneous ventilation with continuous positive airway pressure: assessment in normal volunteers and patients with acute respiratory failure

  • Patrick Wherry
  • Firooz Sangoul
  • Gordon S. Fox
  • Lloyd D. MacLean
Article

Abstract

Continuous positive airway pressures (CPAP) of 0.49 kPa and 0.98 kPa were applied to ten healthy volunteers and nine critically ill patients with acute respiratory failure. A modified Godart-Statham NV 16003 spirometer was used to measure respiratory frequency (f), tidal volume (Vt), oxygen consumption (Vo2), and changes in functional residual capacity (ΔFRC). During CPAP of 0.49 kPa, volunteers had a decrease in f, and increased Vt and minute volume (MV). At 0.98 kPa CPAP, f did not change but Vt and MV significantly increased. Vo2 did not change at either pressure. The volume of ΔFRC increased with an increased level of CPAP. The entire volunteer group was comfortable throughout the whole study.

When CPAP was applied to acutely ill patients, f decreased, Vt and MV increased at both CPAP pressures. ΔFRC was similar to the volunteers. Vo2 in the patient group rose significantly at 0.49 and 0.98 kPa CPAP. Some of the patients were uncomfortable with 0.49 kPa pressure, while all the patients were distressed at 0.98 kPa CPAP.

The effects of increased oxygen consumption and patient discomfort should be considered in critically ill patients receiving CPAP therapy.

Keywords

Continuous Positive Airway Pressure Tidal Volume Acute Respiratory Failure Functional Residual Capacity Respiratory Frequency 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Résumé

On soumis dix volontaires en respiration spontanée à des pressions positives continues (CPAP) de 0.49 et de 0.98 kPa (5 et 10 cm H2O), ainsi que neuf grands malades en insuffisance respiratoire aiguë. Un spiromètre modifié de Godart-Statham N V 16003 a été utilisé pour la mesure de la fréquence respiratoire, du volume courant, de la consommation ďoxygène et des modifications de la capacité fonctionnelle résiduelle.

Une diminution de la fréquence respiratoire avec une augmentation du volume courant et du volume-minute a été observée chez les volontaires soumis à une CPAP de 0.49 kPa. Si on soumettait ces sujets à une CPAP de 0.98 kPa, la fréquence respiratoire demeurait inchangée alors que le volume courant et le volume-minute s’élevaient de façon significative. La consommation ďoxygène ne changeait pas avec ľune ou ľautre des pressions utilisées chez les volontaires. La capacité fonctionnelle résiduelle augmentait en relation avec ľimportance de la CPAP appliquée. Ces sujets sont demeurés confortables durant toute ľépreuve.

La fréquence respiratoire diminuait avec augmentation du volume courant et du volume-minute chez les patients en insuffisance respiratoire aiguë, et ceci aux deux régimes de pression positive. On observait les mêmes modifications de la capacité résiduelle fonctionnelle déjà mentionnées chez les volontaires. Par ailleurs, la consommation ďoxygène s’élevait avec ľutilisation des deux régimes de pression. Avec une CPAP de 0.49 kPa, quelques uns des malades étaient inconfortables, alors que tous ľétaient de façon évidente à 0.98 kPa.

On devrait tenir compte du fait que la consommation ďoxygène est augmentée, ainsi que de ľinconfort des patients lorsque ľon utilise une CPAP chez les grands malades en insuffisance respiratoire aiguë.

Download to read the full article text

References

  1. 1.
    Gregory, G.A., Kitterman, J.A., Phibbes, R.H., Tooley, W.H. &Hamilton, W.K. Treatment of IRDS with continuous positive airway pressure. N. Engl. J. Med.284: 1333–1340 (1971).PubMedGoogle Scholar
  2. 2.
    Civetta. J.M., Brons, R. &Gabel, J.C. A simple and effective method of employing spontaneous positive pressure ventilation. J. Thorac. Cardiovasc. Surg.63: 313–317 (1972).Google Scholar
  3. 3.
    Glasser. K.L., Civetta, J.M. &Flor. R.J. The use of spontaneous ventilation with constant positive airway pressure in the treatment of salt water near drowning. Chest67: 355–357 (1975).PubMedCrossRefGoogle Scholar
  4. 4.
    White, A., Hadler, P. &Smith. E.L. Principles of Biochemistry, Fifth Edition. McGraw-Hill Book Co., New York, pp. 282–283 (1973).Google Scholar
  5. 5.
    Rahn. H., Otis, A.B., Chadwick, L.E. &Fenn, W.O. The pressure-volume diagram of the thorax and lung. Am. J. Physiol.146: 161–178 (1946).Google Scholar
  6. 6.
    Otis, A.B. Handbook of Physiology, Section 3, Respiration, Volume1. Section Editors:Fenn, W.O., Rahn, H. American Physiological Society, Washington, D.C., pp. 463–476 (1964).Google Scholar
  7. 7.
    Agostoni, E. A graphic analysis of thoracoabdominal mechanics during breathing cycle. J. Appl. Physiol.16: 1055–1059 (1961).PubMedGoogle Scholar
  8. 8.
    Mead, J. Measurement of inertia of the lungs at increased ambient pressure. J. Appl. Physiol.9: 208–212 (1956).PubMedGoogle Scholar
  9. 9.
    Dubois. A.B., Brody. A.W., Lewis, D.H. &Burges, B.F. Oscillation mechanics of lungs and chest in men. J. Appl. Physiol.8: 587–594 (1956).PubMedGoogle Scholar
  10. 10.
    Campbell, E.J.M., Agostoni. E. &Davis, J.M. The respiratory muscles: mechanics and neural control. Second edition, W.B. Saunders Co., Philadelphia and London, pp. 115–137 (1970).Google Scholar
  11. 11.
    Karetsky, M.S. &Cain, S.M. Effect of carbon dioxide on oxygen uptake during hyperventilation in normal man. J. Appl. Physiol.28: 8–12 (1970).Google Scholar
  12. 12.
    Milic-Emili, J. &Petit, J.M. Mechanical efficiency of breathing. J. Appl. Physiol.15: 359–362 (1960).Google Scholar
  13. 13.
    Abboud, N., Rehder, K., Rodarte, J.R. &Hyatt, R.E. Lung volumes and closing capacity with continuous positive airway pressure. Anesthesiology42: 138–142 (1975).PubMedCrossRefGoogle Scholar
  14. 14.
    Ferris. B.G., Mead, J. &Opie, L.H. Partitioning of respiratory flow resistance in man. J. Appl. Physiol.19: 653–658 (1964).PubMedGoogle Scholar
  15. 15.
    Briscoe, W.A. &Dubois, A.B. The relationship between airway resistance, airway conductance and lung volume in subjects of different age and body size. J. Clin. Invest.37: 1279–1285 (1958).PubMedCrossRefGoogle Scholar
  16. 16.
    Fisher, A.B., Dubois, A.B. &Hyde, R.W. Evaluation of the forced oscillation technique for the determination of resistance to breathing. J. Clin. Invest.47: 2045–2057 (1968).PubMedGoogle Scholar
  17. 17.
    Grimbly. G., Takishima, T., Graham, W., Macklem, P. &Mead. J. Frequency dependence of flow resistance in patients with obstructive lung disease. J. Clin. Invest.47: 1455–1465 (1968).Google Scholar
  18. 18.
    Barach. A.L., Martin. J. &Eckman, M. Positive pressure respiration and its application to the treatment of acute pulmonary edema. Ann. Intern. Med.72: 754–795 (1938).Google Scholar
  19. 19.
    Barach, A.L., Eckman, M., Ginsburg, E., Rumsey. C.C., Korr. I., Eckman. I. &Dessun, G. Studies on positive pressure respiration: I: General aspects and types of pressure breathing. II: Effects on respiration and circulation at sea level. J. Aviation Medicine17: 290–320 (1946).Google Scholar
  20. 20.
    Askitopoulou, H., Sykes. M.K. &Young, C. Cardiorespiratory effects of increased airway pressure during controlled and spontaneous breathing after cardiac surgery. Br. J. Anaesth.50: 1203–1208 (1978).PubMedCrossRefGoogle Scholar
  21. 21.
    Shah, D.M., Newell, J.C., Dutton. R.E. &Powers, S.R. Continuous positive airway pressure versus positive end-expiratory pressure in respiratory distress syndrome. J. Thorac. Cardiovasc. Surg.74: 557–562 (1977).PubMedGoogle Scholar

Copyright information

© Canadian Anesthesiologists 1980

Authors and Affiliations

  • Patrick Wherry
    • 1
  • Firooz Sangoul
    • 1
  • Gordon S. Fox
    • 1
  • Lloyd D. MacLean
    • 1
  1. 1.Departments of Anaesthesia & SurgeryRoyal Victoria Hospital, & McGill UniversityMontrealCanada

Personalised recommendations