Hemodynamic Instability and Lactate: Key Drivers of AKI Risk in GDV

Gastric dilatation and volvulus (GDV) is often approached as an acute surgical emergency, but its systemic consequences begin much earlier and extend far beyond the stomach. One of the most critical downstream effects is acute kidney injury (AKI), which develops primarily as a consequence of severe hemodynamic compromise. In dogs with GDV, the interplay between circulatory shock, reduced perfusion, and metabolic imbalance creates an environment where renal injury becomes highly likely. 

The pathophysiology of GDV involves mechanical obstruction of venous return, leading to decreased cardiac output and systemic hypotension¹. This results in reduced renal blood flow, making the kidneys particularly vulnerable to ischemic damage. Unlike isolated renal disease, AKI in GDV is rarely due to a single cause, it is typically the result of cumulative insults occurring before, during, and after surgical intervention. 

Blood Pressure and Renal Perfusion 

Blood pressure plays a fundamental role in maintaining adequate renal perfusion. In the study, lower blood pressure at presentation was associated with the presence of AKI. Although this variable did not remain statistically significant in multivariate analysis, its physiological importance cannot be overlooked. 

The kidneys rely on stable perfusion pressure to maintain glomerular filtration. Even short periods of hypotension can disrupt this balance, leading to reduced filtration and subsequent tubular injury^1,2,3. In GDV patients, hypotension is often a reflection of underlying shock, which may include hypovolemic, obstructive, distributive, and cardiogenic components.18 This multifactorial shock state amplifies the risk of renal hypoxia and injury. 

Lactate as a Predictor of Renal Risk 

Among the various clinical parameters evaluated, preoperative lactate emerged as a significant predictor of AKI. For every 0.5 mmol/L increase in lactate concentration, the odds of presenting with AKI increased by 1.2 times¹. 

Lactate is widely recognized as a marker of tissue hypoperfusion and anaerobic metabolism.34 In GDV, elevated lactate levels indicate the severity of circulatory compromise and have been strongly associated with gastric necrosis and poor outcomes^1,4. The findings of this study extend its utility further, positioning lactate as an important indicator of renal vulnerability. 

From a clinical perspective, this means that elevated lactate should not be viewed in isolation. Instead, it should prompt a broader assessment of organ perfusion, including the kidneys. 

Intraoperative Hypotension and Its Impact 

The intraoperative period represents a critical window where renal injury can either be mitigated or exacerbated. In this study, the lowest mean arterial pressure (MAP) recorded during anesthesia was significantly associated with mortality. 

This finding highlights the importance of maintaining adequate perfusion pressure throughout the surgical procedure. Even transient episodes of hypotension can worsen renal ischemia, particularly in patients who are already compromised at presentation¹. 

Anesthesia-induced vasodilation, combined with pre-existing hypovolemia, can further reduce effective circulating volume. Without careful monitoring and timely intervention, this can push the kidneys beyond their compensatory capacity. 

Fluid Therapy and the Role of HES¹ 

Fluid resuscitation is a cornerstone of GDV management, but the choice of fluid can influence outcomes. Hydroxyethyl starch (HES), commonly used for rapid volume expansion, was found to be significantly associated with mortality in this study. 

The relationship between HES and AKI has been extensively debated. While some studies suggest a link between HES use and renal injury, others have not found a definitive association. In the context of GDV, the observed association may reflect the severity of illness, as HES is often reserved for critically unstable patients. 

However, the fact that this association persisted even when blood pressure was considered suggests that HES may have an independent impact on outcomes. This underscores the need for cautious and judicious use of synthetic colloids in GDV patients. 

Clinical Integration and Risk Stratification 

The development of AKI in GDV is closely tied to a combination of hemodynamic and metabolic factors. The presence of hypotension, elevated lactate, and intraoperative instability forms a high-risk profile that clinicians should recognize early. 

By identifying these risk factors at presentation and during surgery, veterinarians can: 

• prioritize aggressive stabilization  

• optimize fluid therapy  

• maintain adequate perfusion pressure  

• monitor renal function more closely  

Conclusion 

AKI in GDV is not an isolated complication but a reflection of systemic hemodynamic failure. Lactate serves as a valuable predictor, while intraoperative management plays a decisive role in determining outcomes. Recognizing and addressing these factors early can significantly influence survival and reduce the burden of renal injury in these critically ill patients.  

References 

1. Suarez-Rodriguez JI, Lourenço BN, Huang JH, Brainard BM, Schmiedt CW. Acute kidney injury is associated with increased mortality in dogs with gastric dilatation and volvulus. Journal of the American Veterinary Medical Association. 2026 Feb 25;1(aop):1-9. https://avmajournals.avma.org/downloadpdf/view/journals/javma/aop/javma.25.11.0716/javma.25.11.0716.pdf 

2. Zarbock A, Koyner JL, Hoste EA, Kellum JA. Update on perioperative acute kidney injury. Anesthesia & Analgesia. 2018 Nov 1;127(5):1236-45. https://journals.lww.com/anesthesia-analgesia/_layouts/15/oaks.journals/downloadpdf.aspx?an=00000539-201811000-00022 

3. Chiu C, Fong N, Lazzareschi D, Mavrothalassitis O, Kothari R, Chen LL, Pirracchio R, Kheterpal S, Domino KB, Mathis M, Legrand M. Fluids, vasopressors, and acute kidney injury after major abdominal surgery between 2015 and 2019: a multicentre retrospective analysis. British Journal of Anaesthesia. 2022 Sep 1;129(3):317-26. https://www.sciencedirect.com/science/article/pii/S0007091222002379 

4. Grassato L, Spinella G, Musella V, Giunti M, Vilar JM, Valentini S. Pre-and post-surgical evaluation of plasma lactate concentration in 45 dogs with gastric dilatation-volvulus: A preliminary study. Heliyon. 2020 Jan 1;6(1). https://www.cell.com/heliyon/pdf/S2405-8440(20)30152-3.pdf