Conditioning of Inspired Gases in Mechanically Ventilated Patients

  • D. Chiumello
  • P. Pelosi
  • L. Gattinoni


When the nose and the upper airways are bypassed due to a tracheostomy or endotracheal tube, their normal function of heating and humidifying the inspired gases is altered. Therefore, in these situations artificial heating and humification of inspired gases is mandatory. The goal of any heating and humidification system is to provide inspired gases with a water content similar to that usually provided by the nose or the upper airways. In this chapter we will discuss:
  • The physical and physiological background

  • The effects of inadequate and excessive conditioning

  • The optimal conditioning

  • The humidifier equipment

  • New devices for conditioning the inspired gases.


Minute Ventilation Absolute Humidity Intubate Patient Ventilator Circuit Heated Humidifier 
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.


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  1. 1.
    Shelly MP, Lloyd GM, Park GR (1988) A review of the mechanisms and methods of humidification of inspired gases. Intensive Care Med 14: 1–9PubMedCrossRefGoogle Scholar
  2. 2.
    Dery R, Pelletier J, Jacques A, Clovet M, Houde JJ (1967) Humidity in anesthesiology III: Heat and moisture patterns in the respiratory procedure during anesthesia with semiclosed system. Can Anaes Soc J 14: 287–298Google Scholar
  3. 3.
    Dery R (1971) Humidity in anaesthesiology. Part IV: Determination of the alveolar humidity and temperature in the dog. Can Anaest Soc J 18: 145–151CrossRefGoogle Scholar
  4. 4.
    Primiano FP, Moranz ME, Montague FW, Miller RB, Sachs DPL (1984) Conditioning of inspired air by a hyroscopic condenser humidifier. Crit Care Med 8: 675–678CrossRefGoogle Scholar
  5. 5.
    Sessler DI, Moayeri A (1990) Skin surface warming: Heat flux and central temperature. Anesthesiology 73: 218–224Google Scholar
  6. 6.
    Graff TD, Benson DW (1968) Systemic and pulmonary changes with inhaled humid atmospheres. Anesthesiology 30: 199–207CrossRefGoogle Scholar
  7. 7.
    Bissonnette B, Sessler DI, LaFlamme P (1989) Intraoperative temperature monitoring sites in infants and children and the effect of inspired gas warming on esophageal temperature. Anesth Analg 69: 192–196PubMedGoogle Scholar
  8. 8.
    Stone DR, Downs JB, Paul WL, Perkins HM (1981) Adult body temperature and heated humidification of anesthetic gases during general anesthesia. Anesth Analg 60: 736–741PubMedCrossRefGoogle Scholar
  9. 9.
    Gentilello LM, Pierson DJ (2001) Trauma critical care. Am J Respir Crit Care 163: 604–607CrossRefGoogle Scholar
  10. 10.
    Marfatia S, Donahue PK, Hendren WH (1975) Effect of dry and humidified gases on the respiratory epithelium in rabbits. J Paediatr Surg 10: 583–592CrossRefGoogle Scholar
  11. 11.
    Fonkalsrud EW, Calmes S, Barciff LT, Borret CT (1980) Reduction of operative heat loss and pulmonary secretions in neonates by use of heated and humidified anesthetic gases. J Thorac Cardiovasc Surg 80: 718–723PubMedGoogle Scholar
  12. 12.
    Kleeman PP (1994) Humidity of anaesthetic gases with respect to low flow anesthesia. Anaesth Intensive Care 22: 396–408Google Scholar
  13. 13.
    Sleigh MA, Blake JR, Liron N (1988) State of the art: the propulsion of mucus by cilia. Am Rev Respir Dis 137: 726–741PubMedCrossRefGoogle Scholar
  14. 14.
    Gawley TH, Dundee W (1981) Attempts to reduce respiratory complications following upper abdominal operations. Br J Anaesth 53: 1073–1077PubMedCrossRefGoogle Scholar
  15. 15.
    Williams RB (1998) The effects of excessive humidity. Respir Care Clin North Am 2: 215–228Google Scholar
  16. 16.
    Klein EF, Groves SA (1974) A hot pot tracheitis. Chest 65: 225–226PubMedCrossRefGoogle Scholar
  17. 17.
    Tsuda T, Noguchi H, Takumi Y, Aochi O (1977) Optimum humidification of air administered to a tracheostomy in dogs. Scanning electron microscopy and surfactant studies. Br J Anaesth 49: 965–977Google Scholar
  18. 18.
    Chatburn RRT, Primiano FP (1987) A rational basis for humidity therapy. Respiratory Care 4: 249–254Google Scholar
  19. 19.
    Johnson JW, Permutt S, Sipple JH, Salem ES (1963) Effect of intra-alveolar fluid on pulmonary surface tension properties. J Appl Physiol 19: 769–785Google Scholar
  20. 20.
    American National Standards Institute (1979) Z79. 9: Humidifiers and Nebulizers for Medical Use. ANSI, WashingtonGoogle Scholar
  21. 21.
    British Standards Institution (1970) BS 4494: Specifications for Humidifiers for Use with Breathing Machines. BSI, LondonGoogle Scholar
  22. 22.
    Kanute PR, Youtsey JW (1981) Respiratory Patient Care. Prentice Hall, Englewood Cliffs, pp 46–60Google Scholar
  23. 23.
    Martin C, Papazian L, Perrin G, Bantz P, Gouin F (1992) Performance evaluation of three vaporizing humidifiers and two heat and moisture exchangers in patients with minute ventilation 10 L/min. Chest 102: 1347–1350PubMedCrossRefGoogle Scholar
  24. 24.
    Unal N, Kanhai JKK, Buijk SLCE, et al (1988) A novel method of evaluation of three heat-moisture exchangers in six different ventilator settings. Intensive Care Med 24: 138–146CrossRefGoogle Scholar
  25. 25.
    Stoutenbeek CH, Miranda D, Zandstra D (1982) A new hygroscopic condenser humidifier. Intensive Care Med 8: 231–234PubMedCrossRefGoogle Scholar
  26. 26.
    Cohen IL, Weinberg PF, Fein A, Rowinski GS (1988) Endotracheal tube occlusion associated with the use of heat and moisture exchangers in the intensive care unit. Crit Care Med 3: 277–279CrossRefGoogle Scholar
  27. 27.
    Roustan JP, Kienlen J, Aubas P, Aubas S, Cailar J (1992) Comparison of hydrophobic heat and moisture exchangers with heated humidifier during prolonged mechanical ventilation. Intensive Care Med 18: 97–100PubMedCrossRefGoogle Scholar
  28. 28.
    Martin C, Thomachot L, Quinio B, Viviand X, Albanese J (1995) Comparing two heat and moisture exchangers with one vaporizing humidifier in patients with minute ventilation greater than 10 L/min. Chest 107: 1411–1415PubMedCrossRefGoogle Scholar
  29. 29.
    Jackson C, Webb AR (1992) An evaluation of the heat and moisture exchange performance of four ventilator circuit filters. Intensive Care Med 18: 264–268PubMedCrossRefGoogle Scholar
  30. 30.
    Pelosi P, Croci M, Solca M (1994) Use of heat and moisture exchangers in mechanically ventilated patients. In: Vincent IL (ed) Yearbook of Intensive Care and Emergency Medicine, Springer, Heidelberg, pp 545–553Google Scholar
  31. 31.
    Mebius C (1983) A comparative evaluation of disposable humidifiers. Acta Anesthesiol Scand 27: 403–409CrossRefGoogle Scholar
  32. 32.
    Chiaranda M, Verona L, Pinamonti O, Dominioni L, Minoja G, Conti G (1993) Use of heat and moisture (HME) filters in mechanically ventilated ICU patients: influence on airway flow-resistance. Intensive Care Med 19: 462–466PubMedCrossRefGoogle Scholar
  33. 33.
    Le Bourdelles G, Mier L, Fiquet B, et al (1996) Comparison of the effects of heat and moisture exchangers and heated humidifiers on ventilation and gas exchange during weaning trials from mechanical ventilation. Chest 110: 1294–1298PubMedCrossRefGoogle Scholar
  34. 34.
    Conti G, De Blasi A, Rocco M, et al (1990) Effect of heat-moisture exchangers on dynamic hyperinflation of mechanically ventilated COPD patients. Intensive Care Med 16: 441–443PubMedCrossRefGoogle Scholar
  35. 35.
    Tobin M (1994) Technical aspects of the patient ventilator interface. In: Tobin MJ (ed) Principles and Practice of Mechanical Ventilation. McGraw-Hill, New York, pp 1039–1065Google Scholar
  36. 36.
    Pelosi P, Solca M, Ravagnan I, Tubiolo D, Ferrario L, Gattinoni L (1996) Effects of heat and moisture exchangers on minute ventilation, ventilatory drive, and work of breathing during pressure support ventilation in acute respiratory failure. Crit Care Med 24: 1184–1188PubMedCrossRefGoogle Scholar
  37. 37.
    Iotti GA, Olivei MC, Braschi A (1999) Mechanical effects of heat moisture exchangers in ventilated patients. Crit Care 3: R77 - R82PubMedCrossRefGoogle Scholar
  38. 38.
    Dreyfuss D, Djedaini K, Gros I, et al (1995) Mechanical ventilation with heated humidifiers or heat and moisture exchangers: effects on patients colonization and incidence of nosocomial pneumonia. Am J Respir Crit Care Med 151: 986–992PubMedGoogle Scholar
  39. 39.
    Thomachot L, Vialter R, Arnaud S, Barberon B, Nguyen AM, Martin C (1999) Do the components of heat and moisture exchangers filters affect their humidifying efficacy and the incidence of nosocomial pneumonia. Crit Care Med 27: 923–928PubMedCrossRefGoogle Scholar
  40. 40.
    Boots RI, Howe S, George N, Harris FM, Faoagali J (1997) Clinical utility of hygroscopic heat and moisture exchangers in intensive care patients. Crit Care Med 25: 1707–1712PubMedCrossRefGoogle Scholar
  41. 41.
    Markowics P, Ricard JD, Dreyfuss D, et al (2000) Safety, efficacy, and cost effectiveness of mechanical ventilation with humidifying filters changed every 48 hours: a prospective, randomized study. Crit Care Med 28: 665–671CrossRefGoogle Scholar
  42. 42.
    Djedaini, Billiard M, Mier L, et al (1995) Changing heat and moisture exchangers every 48 hours rather than 24 hours does not affect their efficacy and the incidence of nosocomial pneumonia. Am J Respir Crit Care Med 152: 1562–1569PubMedCrossRefGoogle Scholar
  43. 43.
    Ricard JD, Le Miere E, Markowics P, et al (2000) Efficiency and safety of mechanical ventilation with a heat and moisture exchanger changed only once a week. Am J Respir Crit Care Med 161: 104–109PubMedCrossRefGoogle Scholar
  44. 44.
    Poulton TJ, Downs JB (1981) Humidification of rapidly flowing gas. Crit Care Med 9: 59–63PubMedCrossRefGoogle Scholar
  45. 45.
    Miyao H, Hirokawa T, Miyasaka K, Kawazoe T (1992) Relative humidity, not absolute humidity, is of great importance when using a humidifier with a heating wire. Crit Care Med 20: 674–679PubMedCrossRefGoogle Scholar
  46. 46.
    Kapadio F, Shelly MP, Anthony JM, Park GR (1992) An active heat and moisture exchanger. B J Anaesth 69: 640–642CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media New York 2002

Authors and Affiliations

  • D. Chiumello
  • P. Pelosi
  • L. Gattinoni

There are no affiliations available

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