Effect of bicarbonated Ringer's solution on PaCO₂ and tissue PO₂ in hemorrhagic shock rats

Background and objectives

Bicarbonated Ringer's solution (BRS) is considered to be an ideal extracellular fluid solution because it contains bicarbonate, which does not need metabolic processes to exert alkalinizing effect. But administration of a large amount of BRS arouses concern about negative effects of acute alkalinizing such as metabolic alkalosis and a leftward shift of Hb-O₂ saturation curves. In this study, we observed an impact of a large amount of BRS on PaCO₂ and tissue PO₂ during hemorrhagic shock.

Methods

Fifty male SD rats were divided into five groups: a sham-operated group (Sham), hemorrhagic shock without infusion (HS group), hemorrhagic shock with infusion of normal saline (NS group) and bicarbonated and acetated Ringer's solutions (BRS and ARS groups). Thirty minutes after hemorrhage (2 ml/100 g), resuscitation fluids (three times as much as bleeding) were administered over 30 min. The tissue PO₂ and laser Doppler tissue blood flow was continuously observed, and blood gas analysis was performed.

Results

HCO₃^- decreased in all the hemorrhagic groups. HCO₃^- increased in the BRS and ARS groups after resuscitation, while it kept decreasing in the NS group. PaO₂ and PaCO₂ recovered to their control values after infusion. PaO₂ kept increasing more, but PaCO₂ gradually decreased after resuscitation.

Conclusion

Even if BRS was infused to large amounts for the hemorrhage shock, metabolic alkalosis did not occur. The difference was not seen on the tissue PO₂ among the resuscitation groups. The repression of breathing was not suggested from this result.

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