Hyperventilation in severe diabetic ketoacidosis.
OBJECTIVE
To explore whether the carbon dioxide-bicarbonate (P(CO(2))-HCO(3)) buffering system in blood and cerebrospinal fluid (CSF) in diabetic ketoacidosis should influence the approach to ventilation in patients at risk of cerebral edema.


METHODS
Medline search, manual search of references in articles found in Medline search, and use of historical literature from 1933 to 1967.


METHODS
A clinical vignette is used--a child with severe diabetic ketoacidosis who presented with profound hypocapnia and then deteriorated--as a basis for discussion of integrative metabolic and vascular physiology.


METHODS
Studies included reports in diabetic ketoacidosis where arterial and CSF acid-base data have been presented. Studies where simultaneous acid-base, ventilation, respiratory quotient, and cerebral blood flow data are available.


METHODS
We revisit a hypothesis and, by reassessing data, put forward an argument based on the significance of low [HCO(3)](CSF) and rising Pa(CO(2))- hyperventilation in diabetic ketoacidosis and the limit in biology of survival; repair of severe diabetic ketoacidosis and Pa(CO(2))-and mechanical ventilation.


CONCLUSIONS
The review highlights a potential problem with mechanical ventilation in severe diabetic ketoacidosis and suggests that the P(CO(2))--HCO(3) hypothesis is consistent with data on cerebral edema in diabetic ketoacidosis. It also indicates that the recommendation to avoid induced hyperventilation early in the course of intensive care may be counter to the logic of adaptive physiology.
University of Cambridge School of Clinical Medicine, Department of Paediatrics, Addenbrooke's Hospital, Cambridge, UK.
Robert C
RC
Tasker
Daniel
D
Lutman
Mark J
MJ
Peters
D000136:Acid-Base Equilibrium / Q000502:physiology; D001639:Bicarbonates / Q000097:blood / Q000134:cerebrospinal fluid; D001929:Brain Edema / Q000378:metabolism / Q000503:physiopathology* / Q000517:prevention & control; D002245:Carbon Dioxide / Q000097:blood / Q000134:cerebrospinal fluid; D002560:Cerebrovascular Circulation / Q000502:physiology; D002648:Child; D016883:Diabetic Ketoacidosis / Q000503:physiopathology / Q000628:therapy*; D005260:Female; D006801:Humans; D006863:Hydrogen-Ion Concentration; D006985:Hyperventilation / Q000378:metabolism / Q000503:physiopathology*; D016014:Linear Models; D012121:Respiration, Artificial / Q000009:adverse effects / Q000379:methods*
D001639:Bicarbonates; D002245:Carbon Dioxide