AKI after cardiac bypass

Q: Addition of mannitol to Cardio-pulmonary Bypass (CPB) in OR reduces the risk of acute kidney injury (AKI) post cardiac surgery?

A) True

B) False

Answer: B

In the past, different modalities have been tried to decrease the risk of AKI post-cardiac surgery, including mannitol, furosemide, and low-dose dopamine (popularly known as renal dose dopamine), but none have been shown to protect against AKI post-bypass. The best approach to prevent AKI post-surgery is to maintain adequate 

• CPB pump flow
• Mean arterial pressure (MAP)
• Mixed Venous Oxygenation (SvO2), and 
• Arterial blood gases (ABGs)

Simultaneously, monitoring urine output to maintain at or above 0.5 mL/kg per hour is the best strategy. If urine output drops, quickly trying to figure out the cause by checking bladder catheter (aka Foley) placement, heart function, and possible development of aortic dissection via transesophageal echocardiography (TEE) must ensue.

#surgical-critical-care

#cardiac-surgery

#cardiology

#nephrology

References:

1. junggren M, Sköld A, Dardashti A, Hyllén S. The use of mannitol in cardiopulmonary bypass prime solution-Prospective randomized double-blind clinical trial. Acta Anaesthesiol Scand 2019; 63:1298.

2. Bell S, Ross VC, Zealley KA, et al. Management of post-operative acute kidney injury. QJM 2017; 110:695.

3. Yang X, Zhu L, Pan H, Yang Y. Cardiopulmonary bypass associated acute kidney injury: better understanding and better prevention. Ren Fail. 2024 Dec;46(1):2331062. doi: 10.1080/0886022X.2024.2331062. Epub 2024 Mar 21. PMID: 38515271; PMCID: PMC10962309.

4. Chu H, Li S, Cao L, Xu G, Yang L, Ma C. Risk factors for acute kidney injury after coronary artery bypass graft surgery: a systematic review and meta-analysis. Front Med (Lausanne). 2026 Feb 24;13:1722801. doi: 10.3389/fmed.2026.1722801. PMID: 41816661; PMCID: PMC12971401.