Could hyperoxic ventilation impair oxygen delivery in septic patients?
OBJECTIVE
In critically ill patients, a decrease in whole body oxygen consumption under hyperoxia has been reported and this could be related to hyperoxia-induced arterial changes. We investigated changes in brachial artery circulation and tone during short-term hyperoxic ventilation in septic patients.


METHODS
Prospective clinical study in the intensive care unit of a university hospital.


METHODS
Fourteen patients (severe sepsis n=3 and septic shock n=11) requiring mechanically controlled ventilation due to sepsis syndrome were investigated under stable clinical conditions.


METHODS
After a 20-min period of hyperoxic ventilation (inspired oxygen fraction = 100%), two-dimensional images of brachial artery cross-sectional area and brachial blood flow velocities were recorded using conventional ultrasonography and pulsed Doppler simultaneously with invasive arterial pressure measurements.


RESULTS
Hyperoxia did not affect heart rate, but increased mean arterial pressure and decreased cross-sectional areas both at the end of diastole and at the end of systole. Haemodynamic study showed an increase in resistance index, and a decrease in distensibility and compliance coefficients. Furthermore, a decrease in brachial artery blood flow and arterial oxygen delivery was observed during hyperoxic exposure.


CONCLUSIONS
Hyperoxia was paradoxically demonstrated to decrease oxygen delivery in upper limbs during septic shock.
Rossi
Pascal
P
Laboratoire de Physiopathologie et Action Thérapeutique des gaz sous pression, IFR Jean Roche, Université de la Méditerranée, Faculté de Médecine Nord, Marseille Cedex, France. pascalrossi@yahoo.com
Tauzin
Laurent
L
Weiss
Michel
M
Rostain
Jean-Claude
JC
Sainty
Jean-Marie
JM
Boussuges
Alain
A
D001783:Blood Flow Velocity; D001916:Brachial Artery / Q000000981:diagnostic imaging; D005260:Female; D006801:Humans; D018496:Hyperoxia / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D010101:Oxygen Consumption / Q000502:physiology*; D011446:Prospective Studies; D012039:Regional Blood Flow; D015203:Reproducibility of Results; D012772:Shock, Septic / Q000503:physiopathology* / Q000628:therapy; D018709:Statistics, Nonparametric; D014463:Ultrasonography