Clinical Case Scenario 1

1. A 64-year-old man is admitted to the hospital with a cough, fever, and low oxygen levels. He quickly progresses to respiratory distress, necessitating endotracheal intubation. A chest x-ray reveals widespread bilateral lung opacities. An arterial blood gas shows a PaO2 of 70 mm Hg on 100% FiO2. Bedside echocardiography confirms normal left ventricular (LV) systolic function. A nasopharyngeal swab tests positive for influenza A.

Wrong Answer: This statement is incorrect. There is substantial evidence supporting fluid management strategies in ARDS patients. Notably, the Fluids and Catheters Treatment Trial (FACTT) demonstrated the benefits of a conservative fluid management approach in ARDS patients..

Wrong Answer: This statement is incorrect. The FACTT study showed that a conservative fluid management strategy can be beneficial in ARDS patients with normal cardiac function. The findings of the FACTT study specifically apply to patients without clinical signs of elevated cardiac filling pressures, so fluid removal strategies can be considered in a broader population than just those with compromised cardiac function.

Wrong Answer: This statement is incorrect. The FACTT study found that a conservative fluid management approach resulted in more ventilator-free and ICU-free days but did not show a significant reduction in overall mortality rates.

Right Answer: This statement is correct. The FACTT study demonstrated that a conservative fluid management strategy resulted in more days without the need for mechanical ventilation and more days outside of the ICU, making this the correct answer.

Wrong Answer: E. This statement is incorrect. The FACTT study showed a trend toward a reduced need for renal replacement therapy (RRT) in the conservative fluid management group. Therefore, a conservative fluid management strategy does not increase the risk of dialysis-requiring acute kidney injury.

Clinical Pearls



AKI and Respiratory Failure

Acute Kidney Injury (AKI) in the context of respiratory failure is particularly dangerous. Each condition independently increases the risk of the other, leading to a 2- to 3-fold increase in mortality when they co-occur. The intricate interplay between the lungs and kidneys involves several mechanisms: AKI-induced inflammation affecting lung endothelium, reduced alveolar fluid clearance due to down-regulation of pulmonary sodium and water channels in AKI, and negative hemodynamic effects of mechanical ventilation on renal blood flow and microvascular circulation.

Management

A crucial aspect of ARDS management is careful fluid balance. The Fluids and Catheters Treatment Trial (FACTT) demonstrated that a conservative fluid strategy results in more ventilator-free and ICU-free days, although it does not impact overall mortality (indicating that D is correct, while A and C are incorrect). There was a trend toward reduced need for renal replacement therapy (RRT) with the conservative strategy, debunking the notion that conservative fluid management increases the risk of dialysis-requiring AKI (making E incorrect). Importantly, the FACTT study excluded patients with clinical signs of elevated cardiac filling pressures, so its findings apply specifically to patients with normal left ventricular function (rendering B incorrect).

Reference:

Alge, J., Dolan, K., Angelo, J., Thadani, S., Virk, M. and Akcan Arikan, A. (2021). Two to Tango: Kidney-Lung Interaction in Acute Kidney Injury and Acute Respiratory Distress Syndrome. Frontiers in Pediatrics, [online] 9, p.744110. doi: https://doi.org/10.3389/fped.2021.744110.

Teixeira JP, Ambruso S, Griffin BR, Faubel S. Pulmonary Consequences of Acute Kidney Injury. Semin Nephrol. 2019;39(1):3–16.

Thompson BT, Chambers RC, Liu KD. Acute Respiratory Distress Syndrome. N Engl J Med. 2017;377(6):562–572.

Clinical Case Scenario 2

2. A 75-year-old man with diabetes mellitus, hypertension, and peripheral vascular disease underwent infra-renal endovascular repair (EVAR) of an 8-cm abdominal aortic aneurysm. Administration of iodinated contrast was used during the procedure. On day 3 following the procedure, serum creatinine rose from a preoperative value of 112 µmol/L to 150 µmol/L. Doppler ultrasound of renal vessels showed no abnormality. Bedside volume assessment using ultrasound was suggestive of euvolemia. A diagnosis of contrast-induced nephropathy (CIN) was suggested.

Wrong Answer: A. A 2017 study (by Lee et al) showed a high incidence of CIN in patients with prolonged duration of the EVAR procedure and higher doses of iodinated contrast medium.[1]

Wrong Answer: B. A 2020 meta-analysis that included over 60 RCTs with 21,293 patients highlighted the significant role of hemodynamic-guided hydration in the prevention of CIN.[2] However, hemodynamic-guided hydration was considered the second-best strategy following the RenalGuard system, which is a closed-loop IV hydration device approved by the FDA for the prevention of acute kidney injury (AKI) in patients at risk for Cardiac surgery-associated AKI (CSA-AKI).

Right Answer: C. Most meta-analyses before 2016 demonstrated that IV sodium bicarbonate was more effective than IV sodium chloride in preventing CIN. However, two recent influential studies concluded that IV sodium bicarbonate provided no benefit over IV sodium chloride in high-risk patients and critically ill patients.3,4 See table 1 for the details regarding major trials on CIN prevention.

Wrong Answer:D. Risk factors for the development of CIN include high osmolality and volume of iodinated contrast medium used, intra-arterial administration of the contrast agent as well as other patient-related factors such as age>75 years, pre-existing CKD, low GFR, albuminuria, DM, low effective circulating blood volume.

Wrong Answer: E. This has been demonstrated by a 2012 systematic review of eleven studies (nine RCTs and two observational studies). Periprocedural renal replacement therapy did not decrease the incidence of CIN compared with standard medical treatment. Hemodialysis was associated with an increased risk of CIN.[5]

Reference:

[1] 1Lee J, Park KM, Jung S, Cho W, Hong KC, Jeon YS, Cho SG, Lee JB. Occurrences and results of acute kidney injury after endovascular aortic abdominal repair?. Vascular Specialist International. 2017 Dec;33(4):135

[2] Cai Q, Jing R, Zhang W, Tang Y, Li X, Liu T. Hydration strategies for preventing contrast‐induced acute kidney injury: a systematic review and bayesian network meta‐analysis. Journal of Interventional Cardiology. 020;2020(1):7292675

[3] Valette X, Desmeulles I, Savary B, Masson R, Seguin A, Sauneuf B, Brunet J, Verrier P, Pottier V, Orabona M, Samba D. Sodium bicarbonate versus sodium chloride for preventing contrast-associated acute kidney injury in critically ill patients: a randomized controlled trial. Critical Care Medicine. 2017 Apr 1;45(4):637-44.

[4] Weisbord SD, Gallagher M, Jneid H, Garcia S, Cass A, Thwin SS, Conner TA, Chertow GM, Bhatt DL, Shunk K, Parikh CR. Outcomes after angiography with sodium bicarbonate and acetylcysteine. New England Journal of Medicine. 2018 Feb 15;378(7):603-14.

[5]Cruz DN, Goh CY, Marenzi G, Corradi V, Ronco C, Perazella MA. Renal replacement therapies for prevention of radiocontrast-induced nephropathy: a systematic review. The American journal of medicine. 2012 Jan 1;125(1):66-78.

[6]Brar SS, Aharonian V, Mansukhani P, Moore N, Shen AY, Jorgensen M, Dua A, Short L, Kane K. Haemodynamic-guided fluid administration for the prevention of contrast-induced acute kidney injury: the POSEIDON randomised controlled trial. The Lancet. 2014 May 24;383(9931):1814-23.

[7]Nijssen EC, Rennenberg RJ, Nelemans PJ, Essers BA, Janssen MM, Vermeeren MA, van Ommen V, Wildberger JE. Prophylactic hydration to protect renal function from intravascular iodinated contrast material in patients at high risk of contrast-induced nephropathy (AMACING): a prospective, randomised, phase 3, controlled, open-label, non-inferiority trial. The Lancet. 2017 Apr 1;389(10076):1312-22.