Effects of ventilation with 100% oxygen during early hyperdynamic porcine fecal peritonitis.
OBJECTIVE
Early goal-directed therapy aims at balancing tissue oxygen delivery and demand. Hyperoxia (i.e., pure oxygen breathing) has not been studied in this context, since sepsis increases oxygen radical production, which is believed to be directly related to the oxygen tension. On the other hand, oxygen breathing improved survival in various shock models. Therefore, we hypothesized that hyperoxia may be beneficial during early septic shock.


METHODS
Laboratory animal experiments.


METHODS
Animal research laboratory at university medical school.


METHODS
Twenty domestic pigs of either gender.


METHODS
After induction of fecal peritonitis, anesthetized and instrumented pigs were ventilated with either 100% oxygen or supplemental oxygen as needed to maintain arterial hemoglobin oxygen saturation > or = 90%. Normotensive and hyperdynamic hemodynamics were achieved using hydroxyethyl starch and norepinephrine infusion.


RESULTS
Before and at 12, 18, and 24 hrs of peritonitis, we measured lung compliance; systemic, pulmonary, and hepatosplanchnic hemodynamics; gas exchange; acid-base status; blood isoprostanes; nitrates; DNA strand breaks; and organ function. Gluconeogenesis and glucose oxidation were calculated from blood isotope and expiratory 13CO2 enrichments during continuous intravenous 1,2,3,4,5,6-(13)C6-glucose. Apoptosis in lung and liver was assessed postmortem (TUNEL staining). Hyperoxia did not affect lung mechanics or gas exchange but redistributed cardiac output to the hepatosplanchnic region, attenuated regional venous metabolic acidosis, increased glucose oxidation, improved renal function, and markedly reduced the apoptotic death rate in liver and lung.


CONCLUSIONS
During early hyperdynamic porcine septic shock, 100% oxygen improved organ function and attenuated tissue apoptosis without affecting lung function and oxidative or nitrosative stress. Therefore, it might be considered as an additional measure in the first phase of early goal-directed therapy.
Barth
Eberhard
E
Sektion Anästhesiologische Pathophysiologie und Verfahrensentwicklung, Universitätsklinikum, Ulm, Germany.
Bassi
Gabriele
G
Maybauer
Dirk M
DM
Simon
Florian
F
Gröger
Michael
M
Oter
Sükrü
S
Speit
Günter
G
Nguyen
Cuong D
CD
Hasel
Cornelia
C
Möller
Peter
P
Wachter
Ulrich
U
Vogt
Josef A
JA
Matejovic
Martin
M
Radermacher
Peter
P
Calzia
Enrico
E
D000818:Animals; D004195:Disease Models, Animal; D005243:Feces; D005260:Female; D006801:Humans; D008297:Male; D018384:Oxidative Stress / Q000502:physiology; D010102:Oxygen Inhalation Therapy / Q000379:methods*; D010538:Peritonitis; D012121:Respiration, Artificial / Q000379:methods*; D012129:Respiratory Function Tests; D012772:Shock, Septic / Q000209:etiology / Q000503:physiopathology / Q000628:therapy*; D013552:Swine