The Overstated Risk of Preoperative Hypokalemia

Preoperative Serum Potassium Levels and Perioperative Outcomes in Cardiac Surgery Patients

“…Hirsch et al 12 confirmed the results found by Vitez et al 11 In 447 patients undergoing elective cardiac or vascular surgery, frequent and complex VAs were common in those with a history of longterm digoxin therapy or congestive heart failure, but hypokalemia or diuretic therapy did not increase the incidence or severity of ectopy. When combined, the 2 latter studies appear to suggest that delaying surgery for potassium replacement, even in the presence of cardiovascular disease, may be unwarranted.…”

“…However, such a recommendation is controversial since in 2 other studies no increase in incidence of intraoperative arrhythmias occurred in patients with low vs normal serum potassium levels. 11,12 These last 2 studies are, however, limited in ways that preclude definite conclusions. First, the inclusion of any electronically detected arrhythmia may overrepresent the true incidence of serious rhythm disturbances; moreover, these electrocardiac perturbations may not represent a true adverse outcome.…”

Routine preoperative testing: a systematic review of the evidence.

“…Concern centres on whether a low preoperative potassium level predisposes towards life-threatening intraoperative arrhythmias, particularly in patients with pre-existing heart disease. Evidence from at least two studies suggests that it does not, 103,104 and if this is so, then the argument for routinely determining (and correcting) serum potassium preoperatively is much diminished.…”

Potassium in the Perioperative Period

“…Despite this evidence, most anaesthetists faced with a hypokalaemic patient in the preoperative period would set up an infusion containing potassium. However, this concept does not find universal support, as Hirsch and colleagues [13] found no major problems in patients with a serum concentration of potassium less than 3 mmol litre" 1 . The problems that did arise, namely cardiac irregularities, were associated more with previous congestive cardiac failure or long-term digoxin therapy.…”