The buffering capacity of crystalloid and colloid resuscitation solutions.

The buffering capacities of common colloid and crystalloid resuscitation solutions were compared in vitro. An equal volume of each resuscitation solution was titrated above and below its initial pH with 0.14 N sodium hydroxide or 0.11 N hydrochloric acid. The volume (+/- S.D.) of titration solution necessary to lower the pH one unit (7.1-6.1) in these solutions was less than 0.5 ml for normal saline, less than 0.5 ml for Ringer's lactate, 1.9 +/- 0.1 ml for Plasmalyte-A, 2.0 +/- 0.23 ml for Plasmalyte-R, 8.8 +/- 0.17 ml for human serum albumin (HSA), 45 +/- 2.2 ml for human fresh frozen plasma (FFP), and 50 +/- 6.6 ml for swine FFP. With the method of this in vitro study, human fresh frozen plasma was 25-50 times better as an acid buffer than the crystalloid solutions and approx. 5 times better than human serum albumin (HSA). On an equal volume basis, it was the superior resuscitation solution as a buffer, probably because of combined bicarbonate and protein content.