Meet The Author
May 2025
Maxime Cambournac Dr Vet, Dip ECVECC
I’m Maxime Cambournac, a Diplomate of the ECVECC and head of the Emergency and Intensive Care Unit at CHV Frégis in Paris, France. My clinical and research interests include hemodynamic physiology, extracorporeal therapies, POCUS, and liver support.
Moumadah Y, Combet-Curt J, Pouzot-Nevoret C, Barthelemy A, Cambournac M
The Study Background
During my residency, I initiated research on the caudal vena cava-to-aorta (CVC:Ao) ratio as a sonographic marker for assessing volemic status in dogs. This early work focused on developing and validating a method to evaluate blood volume using ultrasonography, aiming to provide a non-invasive tool for clinicians to assess and monitor canine patients effectively. Building upon this foundation, I pursued further research to explore the clinical applications of the CVC:Ao ratio, particularly in diagnosing and managing pericardial effusion and cardiac tamponade in dogs. This progression allowed me to investigate how this ratio could serve as a reliable, non-invasive diagnostic marker, enhancing the accuracy of assessments and informing treatment strategies for these critical conditions.
What is the primary knowledge gap your study aims to address?
The primary knowledge gap our study aims to address is the absence of specific, non-invasive, and quantitative markers to assess the hemodynamic significance of pericardial effusion and identify cardiac tamponade in dogs. While pericardial effusion is a recognized and potentially life-threatening condition, distinguishing between dogs with and without tamponade physiology remains a clinical challenge—particularly in emergency settings where rapid decision-making is essential.
Additionally, we lacked information on how quickly hemodynamic parameters normalize after pericardiocentesis. Although pericardiocentesis is known to be effective in relieving tamponade, there was limited data on the speed and magnitude of physiological improvement immediately following the procedure. By evaluating the CVC:Ao ratio and other Doppler-derived variables before and after pericardiocentesis, our study aimed to fill this dual gap: identifying objective markers of tamponade and documenting the timeline of hemodynamic recovery post-intervention.
The Study Design
The paper was designed as a prospective, observational study conducted in a clinical setting. The primary objective of this study was to evaluate the utility of the caudal vena cava-to-aorta (CVC:Ao) ratio and selected Doppler-derived variables as indicators of cardiac tamponade in dogs presenting with pericardial effusion. A secondary objective was to assess the changes in these parameters immediately after pericardiocentesis, providing insight into the rapidity and extent of hemodynamic improvement following fluid removal.
What are the main study results?
The CVC:Ao ratio was significantly higher in dogs with cardiac tamponade compared to those with pericardial effusion but no tamponade, suggesting its potential value as a non-invasive indicator of tamponade physiology.
• After pericardiocentesis, there was a significant and rapid decrease in the CVC:Ao ratio, indicating swift hemodynamic improvement following removal of pericardial fluid.
• Several Doppler-derived parameters, including aortic flow velocity and acceleration time, also significantly improved post-pericardiocentesis, supporting the dynamic nature of these markers in tracking clinical response.
• These findings collectively support the use of CVC:Ao ratio and Doppler variables as both diagnostic and monitoring tools in dogs with pericardial effusion, particularly in identifying tamponade and assessing recovery after intervention.
Were there any unexpected results or challenges during your research?
Firstly, while our results confirmed recent reference values for the CVC:Ao ratio in healthy dogs, we were encouraged to see that our data aligned well with and reinforced the growing body of literature supporting its clinical use. This convergence adds strength to the CVC:Ao ratio as a reliable, reproducible marker—not just of volemic status, as initially described, but also of tamponade physiology in the context of pericardial effusion.
Secondly, one of the most unexpected findings was how rapidly hemodynamic parameters normalized after pericardiocentesis. We anticipated improvement, but the speed and magnitude of the recovery—within minutes of fluid removal—was more pronounced than expected. This underscores the dynamic and reversible nature of tamponade physiology and highlights the value of timely intervention.
Takeaways from this study
This study has reinforced the clinical value of integrating the CVC:Ao ratio into the initial POCUS triage of patients presenting in shock. While the traditional approach often emphasizes identifying hypovolemia, our findings suggest that the CVC:Ao ratio can also help detect signs of venous congestion or volume overload, such as in cases of pericardial tamponade.
Incorporating this simple, non-invasive measurement early in the evaluation process can provide crucial direction—helping to differentiate between hypovolemic and congestive states, and thereby guiding more appropriate and timely therapeutic decisions. It adds another dimension to the POCUS toolkit and supports a more nuanced approach to hemodynamic assessment in unstable patients.
What future directions would you like to explore based on this study?
Based on the findings of this study, I would be particularly interested in exploring the relationship between central venous pressure (CVP) and the CVC:Ao ratio. While the CVC:Ao ratio offers a non-invasive surrogate for assessing volume status and venous congestion, correlating it with direct CVP measurements could validate its accuracy and refine its clinical interpretation—especially in critical care and emergency settings.
