A comparison of distilled water and normal saline as diluents for endobronchial administration of epinephrine in the dog

We compared the effects of distilled water and normal saline as diluents fo r the endobronchial administration of epinephrine in anesthetized dogs by u sing a crossover design. Six dogs received 2 mL of either normal saline or distilled water into the bronchus, and the other solution was administered 1 wk later. Eight dogs received 0.02 mg/kg epinephrine diluted in either di stilled water (E + water) or normal saline (E + saline) to a total volume o f 2 mt into the bronchus, and the other solution was administered 1 wk late r. Normal saline or distilled water without epinephrine did not affect the plasma epinephrine concentration, mean arterial pressure (MAP), and Pao(2). The peak plasma epinephrine concentration was significantly larger after t reatment with E + water (26.5 +/- 7.9 ng/mL) than after E + saline (2.1 +/- 0.7 ng/mL). E + water caused an increase in MAP of 91 +/- 24 mm Hg, wherea s E + saline did not affect MAP. The maximal decrease in Pao(2) after the a dministration of E + water (14 +/- 5 mm Hg) was significantly greater than after E + saline (7 +/- 2 mm Hg). In conclusion, distilled water as the dil uent for endobronchially administered epinephrine to a total volume of 2 mt allowed better absorption of epinephrine compared with normal saline witho ut a serious detrimental effect on Pao(2).