Effects of phenylephrine on tissue gas tension, bleeding, infection, and lidocaine absorption.

In an attempt to find a vasoconstrictor with less detrimental local and systemic effects than epinephrine, the effects of phenylephrine, a pure alpha agonist, on tissue gas tension, bleeding, infection rates, and lidocaine absorption were studied. All concentrations of phenylephrine significantly reduced tissue PO2 within 10 minutes of injection, and reduction of PO2 was dose-dependent. Phenylephrine 1:10,000 produced significant bacterial growth when simultaneously injected with 6 X 10(6) Staphylococcus aureus. Bacterial growth was insignificant with 1:20,000 phenylephrine and absent with 1:40,000 phenylephrine. Blood loss from a standard wound was significantly reduced at all concentrations of phenylephrine. Lidocaine absorption was significantly reduced with 1:20,000 and 1:40,000 phenylephrine. In a rat model, 1:40,000 phenylephrine significantly reduced blood loss and lidocaine absorption, produced minimal reduction of tissue PO2, and did not enhance bacterial invasion.