Hypotension due to 5 per cent plasma protein fractions

Correlation of hypotensive effect of plasma protein fraction with prekallikrein activator activity: a clinical study in patients having open-heart surgery

We studied the hemodynamic responses to the administration of 20 ml of three protein solutions having different prekallikrein activator (PKA) activities in patients undergoing cardiac operation. PKA levels of the two plasma protein fraction (PPF) solutions studied were 193% and 60%, respectively, while that of the albumin solution was less than or equal to 3%. A significant correlation was found between the PKA activity of the test solutions and the decrease in systemic vascular resistance produced by the solutions during cardiopulmonary bypass and in the postoperative period. Vasodilatation was considerably more marked in the postoperative phase than during cardiopulmonary bypass. Since cardiac output increased simultaneously with the decrease in vascular resistance in the postoperative period, the hypotension observed did not fully reflect the degree of vasodilatation. In some patients, substantial vasodilatation was observed also after the administration of albumin solution with low PKA level. We conclude that although the PPF-induced vasodilatation correlates with the PKA activity of the solution, occasional hypotensive reactions are probably due to mechanisms other than those linked with increased PKA level.

Venoconstrictor activity of some precursor fractions of stable plasma protein solution

Stable plasma protein solution (SPPS) is a 5% solution of human plasma albumin and some globulins. Rapid infusion of some batches of SPPS and analogous solutions prepared by similar processes induce paradoxical hypotensive reactions. In the current experiments, a number of precursor fractions of a single batch of SPPS were examined for kininogen content and for venoconstrictor activity on the isolated central vein of the rabbit ear. Unheated SPPS contained both venoconstrictor activity and kininogen. Among the various precursor fractions examined, Cohn fraction II + III (a precursor of fraction III-0) contained the greatest venoconstrictor activity. There was no evidence of kininogen depletion during the stages of fractionation examined but some generation of venoconstrictor material. Column chromatography suggested a molecular weight of approximately 1,500 for the major active material in unheated SPPS. It appears possible that the 14-amino acid hypotensive peptide present in fraction III-0 may also be present in SPPS, where it may contribute to the hypotensive effects of this solution.

Bradykinin, plasma protein fraction, and hypotension

A directive from the Food and Drug Administration indicates that the use of plasma protein fraction (PPF) is contraindicated during cardiopulmonary bypass because of possible hypotension. Bradykinin has been implicated as the cause of this hypotension. Bradykinin levels were measured by radioimmunoassay in PPF and in 5% albumin and were found to be consistently elevated in the former and occasionally in the latter. The addition of PPF to pump primes resulted in significantly elevated levels of bradykinin, which rapidly cleared, indicating that extrapulmonary sites of bradykinin inactivation were efficient. The potential hypotensive effect of PPF was observed by determining the change in mean perfusion pressure in two groups of patients: one group with a 3,000 ml crystalloid prime and the other with a prime of 2,000 ml of crystalloid and 1,000 ml of PPF. There was no significant difference in the perfusion pressure between the two groups at any point, and the hypotensive effects seen in both groups were readily treated, suggesting that the directive against the use of PPF during cardiopulmonary bypass may be unnecessarily restrictive.

Reactions to rapid infusion of stable plasma protein solution during large volume plasma exchange

Five per cent heat treated stable plasma protein solution (SPPS) has been rapidly infused into 25 patients, as fluid replacement during large volume plasmapheresis. Reactions were produced in 20 patients. Subjective symptoms of flushing, nasal stuffiness, fullness and throbbing in the head, colicky abdominal pain, metallic taste or apprehension were observed in 16 patients, and 11 patients became hypotensive with an average systolic pressure of 70 mm Hg. These observations support earlier reports of hypotension due to rapid SPPS infusion, and document the occurrence of subjective symptoms which may be the harbingers of a hypotensive reaction. In view of the known presence of a bradykinin-like substance in some heat treated plasma protein solutions, hypotension during SPPS infusion should be interpreted with caution in the light of these findings.