Treating metabolic acidosis
Sir,In their detailed and very interesting paper, Maccari et al.1 write (p. 483) that in the approach to the patient with metabolic acidosis the first point is to ‘look for threats to survival, and deal with them promptly’.
However, in Table 2 (p. 476) ‘Major threats in the patient with metabolic acidosis’, there are some discrepancies with the literature. According to this table, ‘haemodynamic issues’ are most important. In contrast to experimental animals and isolated organs, in human patients a very low blood pH has no adverse effects on the cardiovascular system.2, 3 On the other hand, according to Alberti et al.4 and Edge et al.,5 the most dangerous consequence of low blood pH is decreasing level of consciousness ending in lethal coma: the pH-dependent glycolytic enzyme phosphofructokinase is inhibited by decreasing pH and, thus, glucose utilization in brain cells is impaired.
In their ‘Case description’ (Appendix, p. 485) there is no emphasis on cardiovascular signs and symptoms caused by low blood pH. However, the patient ‘was drowsy, but easily roused’. According to both Alberti et al.4 and Edge et al.,5 this is an usual finding in patients with blood pH around 7.00 (as in this patient: Table 1, p. 476). It is likely that after administration of NaHCO3 (p. 481) the patient recovered full alertness.
SYNLAB
Department of Clinical Biochemistry
Dérer's Hospital,
Bratislava
Slovakia
email: rosivalv{at}hotmail.com
References
1. Maccari C, Kamel KS, Davids MA, Halperin ML. (2006) The patient with a severe degree of metabolic acidosis: a deductive analysis. Q J Med 99 475–85.
2. Vallet B, Robin E, Wiel E. (1999) Réponses d’organes à l’acidose métabolique. Réanimation Urgences 8 460–8.[CrossRef]
3. Maury E, Vassal T, Offenstadt G. (1999) Cardiac contractility during severe ketoacidosis. N Engl J Med 341 1938.
4. Alberti KGMM, Zimmet P, DeFronzo RA, Keen H. (1997) International Textbook of Diabetes Mellitus, 2ndChichester John Wiley and Sons pp. 1218.
5. Edge JA, Roy Y, Bergomi A, Murphy NP, Ford-Adams MS, Ong KK, Dunger DB. (2006) Conscious level in children with diabetic ketoacidosis is related to severity of acidosis and not to blood glucose concentration. Pediatr Diabetes 7 11–15.[ISI][Medline]
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