Bicarbonate in Cardiac Surgery

• Status: Terminated
• Trial end date: 2012-01-01
• Target enrollment: 0
• Participant gender: All

Summary

With over one million operations a year, cardiac surgery with cardiopulmonary bypass is one of the most common major surgical procedures worldwide (1). Acute kidney injury is a common and serious postoperative complication of cardiopulmonary bypass and may affect 25% to 50% of patients (2-4). Acute kidney injury carries significant costs (4) and is independently associated with increased morbidity and mortality (2,3). Even minimal increments in plasma creatinine are associated with an increase in mortality (5,6).

Multiple causes of cardiopulmonary bypass-associated acute kidney injury have been proposed, including ischemia-reperfusion, generation of reactive oxygen species, hemolysis and activation of inflammatory pathways (7-10). To date, no simple, safe and effective intervention to prevent cardiopulmonary bypass-associated acute kidney injury in a broad patient population has been found (11-14).

Urinary acidity may enhance the generation and toxicity of reactive oxygen species induced by cardiopulmonary bypass (10,15). Activation of complement during cardiac surgery (16) may also participate in kidney injury. Urinary alkalinization may protect from kidney injury induced by oxidant substances, iron-mediated free radical pathways, complement activation and tubular hemoglobin cast formation (9,17,18). Of note, increasing urinary pH - in combination with N-acetylcysteine (19,20) or without (21) - has recently been reported to attenuate acute kidney injury in patients undergoing contrast-media infusion.

In a pilot double-blind, randomized controlled trial the investigators found sodium bicarbonate to be efficacious, safe, inexpensive and easy to administer. These findings now need to be confirmed or refuted by further clinical investigations in other geographic and institutional settings.

Accordingly, the investigators hypothesized that urinary alkalinization might protect kidney function in patients at increased risk of acute kidney injury undergoing cardiopulmonary bypass needs to be confirmed in an international multicenter, double-blind, randomized controlled trial of intravenous sodium bicarbonate.

• Phase: Phase 2
• Accepts Healthy Volunteers?: No

Details

• Lead Sponsor: Austin Health
• Treatments: Anesthetics

Criteria

Inclusion Criteria:

• Age above 70 years

• Pre-existing renal impairment (preoperative plasma creatinine concentration > 1.4 mg/dL

• New York Heart Association class III/IV or impaired left ventricular function (left ventricular ejection fraction < 50%)

• Valvular surgery or concomitant valvular and coronary artery bypass graft surgery

• Redo cardiac surgery

• Insulin-dependent diabetes mellitus

Exclusion Criteria:

• End stage renal disease (plasma creatinine concentration > 3.4 mg/dL)

• Emergency cardiac surgery

• Planned off-pump cardiac surgery

• Known blood-borne infectious disease

• Chronic inflammatory disease on immunosuppression

• Chronic moderate to high dose corticosteroid therapy (> 10 mg/d prednisone or equivalent)

• Enrolled in conflicting research study

• Age < 18 years