Sublingual capnometry tracks microcirculatory changes in septic patients.
OBJECTIVE
To test the hypothesis that microcirculatory blood flow is the main determinant of sublingual carbon dioxide pressure in patients with septic shock.


METHODS
Prospective, open-label study.


METHODS
A 31-bed medico-surgical department of intensive care.


METHODS
Eighteen consecutive mechanically ventilated patients with septic shock.


METHODS
A 5 microg/kg x min dobutamine infusion was used to increase blood flow.


METHODS
Sublingual carbon dioxide pressure was monitored using a microelectrode sensor, and sublingual microcirculation was assessed using orthogonal polarization spectral imaging. The sublingual carbon dioxide pressure gap was calculated as the difference between sublingual and arterial carbon dioxide pressures. In each patient, a nasogastric tonometry catheter was inserted for gastric mucosal carbon dioxide pressure measurement. The gastric carbon dioxide pressure gap was calculated as the difference between gastric mucosal and arterial carbon dioxide pressures.


RESULTS
Dobutamine infusion was associated with increases cardiac index and mixed venous blood oxygen saturation. Dobutamine infusion resulted in decreases in sublingual carbon dioxide pressure gap from 40+/-15 to 17+/-8 mmHg (p<0.01). There was a significant correlation between sublingual and gastric mucosal carbon dioxide pressures (r 2=0.61, p<0.05). At baseline, sublingual carbon dioxide pressure gap correlated with the proportion of well-perfused capillaries (r 2=0.80). The decrease in sublingual carbon dioxide pressure gap paralleled the increase in the proportion of well-perfused capillaries in each patient.


CONCLUSIONS
Regional microcirculatory blood flow is the main determinant of sublingual carbon dioxide pressure. Sublingual capnometry could represent a simple, non-invasive method to monitor these microcirculatory alterations in septic patients.
Department of Intensive Care, Erasme University Hospital, Route de Lennik 808, 1070, Brussels, Belgium.
Jacques
J
Creteur
Daniel
D
De Backer
Yasser
Y
Sakr
Marc
M
Koch
Jean-Louis
JL
Vincent
D000368:Aged; D001530:Belgium; D001785:Blood Gas Monitoring, Transcutaneous / Q000379:methods*; D002316:Cardiotonic Agents / Q000008:administration & dosage / Q000494:pharmacology; D004280:Dobutamine / Q000008:administration & dosage / Q000494:pharmacology; D005260:Female; D006801:Humans; D007362:Intensive Care Units; D008297:Male; D008833:Microcirculation / Q000502:physiology*; D008875:Middle Aged; D009060:Mouth Floor / Q000098:blood supply*; D012039:Regional Blood Flow / Q000187:drug effects; D012106:Research; D012772:Shock, Septic / Q000503:physiopathology*
D002316:Cardiotonic Agents; D004280:Dobutamine