The Journal of Thoracic and Cardiovascular Surgery, Vol 79, 237-240, Copyright © 1980 by The American Association for Thoracic Surgery and The Western Thoracic Surgical Association
Peripheral vascular response to potassium administration during cardiopulmonary bypass
AJ Schwartz, TJ Conahan 3d, DR Jobes, RW Andrews, H Mac Vaugh 3d and AJ Ominsky
Potassium (K+) is often administered to patients during cardiopulmonary
bypass (CPB). The effects of rapid K+ administration during CPB were
studied in 30 adult patients. Each patient received one bolus dose (2, 4,
8, 12, or 16 mEq) of potassium chloride (KCl) (2 mEq/ml) during CPB. Serum
K+ was significantly increased from baseline values at KCl doses of 8 mEq
and larger (p less than 0.05). All increases in serum K+ returned to
clinically acceptable levels within 5 minutes after the bolus. Mean
arterial pressure (MAP) (torr) and total peripheral resistance (TPR) (dynes
sec cm-5) changes were biphasic; after an initial transient decrease,
maximal with the 16 mEq K+ bolus (MAP -21 +/- 6, TPR - 315 +/- 135), these
parameters increased (8 mEq K+ bolus, MAP + 15 +/- 16, TPR + 301 +/- 90; 12
mEq K+ bolus, MAP + 43 +/- 9, TPR + 998 +/- 250; 16 mEq bolus, MAP + 51 +/-
9, TPR + 1,216 +/- 120) with a peak at 3 minutes after the bolus.
Hypertension, in nine of 18 patients receiving a KCl bolus of 8 mEq or
larger, was of such magnitude (range 132 to 196 torr) as to require rapid
therapeutic intervention to lower blood pressure. When KCl supplementation
is required on CPB and slow infusion rates seem unreasonable, bolus doses
of less than 8 mEq may be administered without vascular effect.