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.

Calcium and Dengue Virus

Q: Dengue virus infection causes? - select one

A) hypercalcemia

B) hypocalcemia 

Answer: B

Most of the treatment for the Dengue virus during all three phases of the Dengue virus, i.e., early, critical, and recovery phase, is essentially supportive. One of the unique features of the Dengue virus is hypocalcemia, and its cause is still not well understood. That said, it is significant, as the level of hypocalcemia correlates with the severity of illness. Its clinical significance can be understood from the perspective that, in resource-limited countries where the dengue virus is common, and labs may not be readily available, calcium should be replaced empirically, correlating clinically with the level of shock.

Development of seizures or arrhythmia due to hypocalcemia predicts poor outcome and requires constant monitoring and replacement, particularly in the critical phase. IV calcium gluconate is preferred. Replacement of calcium also helps restore the coagulation defects, a cardinal feature of Dengue virus infection.

#ID

References;

1. Pourzangiabadi M, Najafi H, Fallah A, Goudarzi A, Pouladi I. Dengue virus: Etiology, epidemiology, pathobiology, and developments in diagnosis and control - A comprehensive review. Infect Genet Evol. 2025 Jan;127:105710. doi: 10.1016/j.meegid.2024.105710. Epub 2024 Dec 26. PMID: 39732271.

2. Shivanthan MC, Rajapakse S. Dengue and calcium. Int J Crit Illn Inj Sci 2014; 4:314.

3. Constantine GR, Rajapakse S, Ranasinghe P, et al. Hypocalcemia is associated with disease severity in patients with dengue. J Infect Dev Ctries 2014; 8:1205.