Interpretation of Changes in Regional and Mucosal PCO2 Gradients: The Haldane Effect

  • S. M. Jakob
  • J. Takala
Conference paper
Part of the Yearbook of Intensive Care and Emergency Medicine book series (YEARBOOK, volume 2000)

Abstract

The basis for gastrointestinal tonometry was published in 1964 [1]. In the 1980s saline tonometry for the assessment of the adequacy of local gastrointestinal perfusion was introduced in clinical practice, and since then, the technique has been developed further towards semi-continuous automated air tonometry. In order to link the measurement with a clinically used physiologic variable for the assessment of the adequacy of the perfusion, the calculated intramucosal pH (pHi) rather than the measured PCO2 was reported in most of the early trials. For the calculation of the pHi the Henderson-Hasselbalch equation was used, and it was assumed that the mucosal bicarbonate would equal the arterial bicarbonate. This assumption has produced substantial debate [2]. Nevertheless, pHi on intensive care admission has been found to be related to outcome in several trials [3–8]. The results from trials investigating the predictive value of gastric mucosal acidosis after an initial period of treatment in the intensive care unit (ICU) have been conflicting, demonstrating both a strong [7] and an absent relationship [9]. The association between increasing mucosal-arterial PCO2 gradients or mucosal acidosis and gastrointestinal hypoperfusion have been demonstrated both in animal experiments [10] and in human trials [11]. However, the effect of therapeutic interventions aiming to improve gastric mucosal acidosis or increase mucosal-arterial PCO2 gradients have produced conflicting results: While peri-operative volume loading seems to increase gastric pHi [12], we have reported worsening gastric mucosal acidosis in patients treated with various vasoactive drugs despite an increased total splanchnic blood flow [13,14]. Moreover, a dissociation between the assessment of mucosal perfusion using laser Doppler flowmetry or spectrophotometry and gastric tonometry, both during rewarming after cardiac surgery (Thorén A et al., unpublished data) and in response to vasoactive treatment [15] have been found.

Keywords

Placebo Dioxide Hydrate Bicarbonate Washout 

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References

  1. 1.
    Bergofsky EH (1964) Determination of tissue 02 tensions by hollow visceral tonometers: effect of breathing enriched 02 mixtures. J Clin Invest 43: 193–200PubMedCrossRefGoogle Scholar
  2. 2.
    Benjamin E, Oropello JM (1996) Does gastric tonometry work? No. Crit Care Clin 12: 587–601PubMedCrossRefGoogle Scholar
  3. 3.
    Doglio GR, Pusajo JF, Egurrola MA, et al (1991) Gastric mucosal pH as a prognostic index of mortality in critically ill patients. Crit Care Med 19: 1037–1040PubMedCrossRefGoogle Scholar
  4. 4.
    Mohsenifar Z, Collier J, Koerner SK (1996) Gastric intramural pH in mechanically ventilated patients. Thorax 51: 606–610PubMedCrossRefGoogle Scholar
  5. 5.
    Gutierrez G, Palizas F, Doglio G, et al (1992) Gastric intramucosal pH as a therapeutic index of tissue oxygenation in critically ill patients. Lancet 339: 195–199PubMedCrossRefGoogle Scholar
  6. 6.
    Marik PE (1993) Gastric intramucosal pH. A better predictor of multiple organ dysfunction syndrome and death than oxygen-derived variables in patients with sepsis. Chest 104: 225–229PubMedCrossRefGoogle Scholar
  7. 7.
    Maynard N, Bihari D, Beale R, et al (1993) Assessment of splanchnic oxygenation by gastric tonometry in patients with acute circulatory failure. JAMA 270: 1203–1210PubMedCrossRefGoogle Scholar
  8. 8.
    Hatherill M, Tibby SM, Evans R, Murdoch IA (1998) Gastric tonometry in septic shock. Arch Dis Child 78: 155–158PubMedCrossRefGoogle Scholar
  9. 9.
    Jakob SM, Kogan A, Takala J (1998) Does gastric mucosal hypercarbia reflect severity of illness rather than response to treatment? Intensive Care Med 25: 60a (Abst)Google Scholar
  10. 10.
    Antonsson JB, Boyle CC 3d, Kruithoff KL, et al (1990) Validation of tonometric measurement of gut intramural pH during endotoxemia and mesenteric occlusion in pigs. Am J Physiol 259: G519 - G523PubMedGoogle Scholar
  11. 11.
    Hamilton-Davies C, Mythen MG, Salmon JB, Jacobson D, Shukia A, Webb AR (1997) Comparison of commonly used clinical indicators of hypovolemia with gastrointestinal tonometry. Intensive Care Med 23: 276–281PubMedCrossRefGoogle Scholar
  12. 12.
    Mythen MG, Webb AR (1995) Perioperative plasma volume expansion reduces the incidence of gut mucosal hypoperfusion during cardiac surgery. Arch Surg 130: 423–429PubMedCrossRefGoogle Scholar
  13. 13.
    Parviainen I, Ruokonen E, Takala J (1995) Dobutamine-induced dissociation between changes in splanchnic blood flow and gastric intramucosal pH after cardiac surgery. Br J Anaesth 74: 277–282PubMedCrossRefGoogle Scholar
  14. 14.
    Uusaro A, Ruokonen E, Takala J (1995) Gastric mucosal pH does not reflect changes in splanchnic blood flow after cardiac surgery. Br J Anaesth 74: 149–154PubMedCrossRefGoogle Scholar
  15. 15.
    Temmesfeld-Wollbruck B, Szalay A, Mayer K, Olschewski H, Seeger W, Grimminger F (1998) Abnormalities of gastric mucosal oxygenation in septic shock: partial responsiveness to dopexamine. Am J Respir Crit Care Med 157: 1586–1592PubMedCrossRefGoogle Scholar
  16. 16.
    Stevens MH, Thirlby RC, Feldman M (1987) Mechanism for high PCO2 in gastric juice: roles of bicarbonate secretion and CO2 diffusion. Am J Physiol 253: G527 - G530PubMedGoogle Scholar
  17. 17.
    Nunn JF (1993) Nunn’s applied respiratory physiology, 4th edn. Butterworth-Heinemann, OxfordGoogle Scholar
  18. 18.
    Morris RC Jr (1968) An experimental renal acidification defect in patients with hereditary fructose intolerance. I. Its resemblance to renal tubular acidosis. J Clin Invest 47: 1389–1398PubMedCrossRefGoogle Scholar
  19. 19.
    Klocke RA (1991) Kinetic measurements of gas exchange in the intact pulmonary micocirculation. J Appl Physiol 71: 2536–2542PubMedGoogle Scholar
  20. 20.
    Trager K, Brinkmann A, Radermacher P (1998) Gastric mucosal tonometry: more than splanchnic circulation and oxygenics. Anasthesiol Intensivmed Noffallmed Schmerzther 33: S91 - S93CrossRefGoogle Scholar
  21. 21.
    Giovannini I, Chiarla C, Boldrini G, Castagneto M (1993) Calculation of venoarterial CO2 content difference. J Appl Physiol 74: 959–964PubMedGoogle Scholar
  22. 22.
    Jakob SM, Kusonen P, Ruokonen E, Parviainen I, Takala J (1999) The Haldane effect–an alternative explanation for increasing gastric mucosal PCO2 gradients? Br J Anaesth 83: 740–746PubMedCrossRefGoogle Scholar

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© Springer-Verlag Berlin Heidelberg 2000

Authors and Affiliations

  • S. M. Jakob
  • J. Takala

There are no affiliations available

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