New consensus redefines sepsis and septic shock in dogs and cats

CURRENT FULL VERSION: Veterinary emergency and critical care clinicians have a new consensus framework for one of the field’s most consequential syndromes: sepsis. In July 2026, the Journal of Veterinary Emergency and Critical Care published two linked consensus papers that redefine sepsis and septic shock in dogs and cats, replacing the long-used “SIRS plus suspected or confirmed infection” model with a definition that requires organ dysfunction. The lead paper defines sepsis as a life-threatening syndrome associated with a dysregulated host response to infection resulting in organ dysfunction, while the companion paper defines septic shock as a higher-risk subset of sepsis associated with cardiovascular instability and metabolic abnormalities despite adequate fluid resuscitation. (pubmed.ncbi.nlm.nih.gov)

This shift has been building for several years. Human medicine moved away from SIRS-based sepsis definitions in 2016 with Sepsis-3, and veterinary leaders had increasingly argued that the profession needed a more coherent, species-appropriate standard. A 2024 position statement in the same journal laid out that problem directly, noting that veterinary definitions had fallen out of alignment with human medicine and that the lack of consensus was limiting both bedside recognition and research comparability. By the 2025 ACVIM Forum, the working group had already signaled plans for retrospective review and multicenter prospective data collection to test a new consensus definition. The process itself began in 2023 and used a modified Delphi method, with 12 specialists in emergency and critical care, infectious disease, and sepsis from six countries spanning academia and private practice drafting, debating, revising, and voting on the final language. (pubmed.ncbi.nlm.nih.gov)

The new papers are substantial evidence reviews, not just expert opinion. According to the PubMed record, the sepsis-definition paper drew on a systematic review process that screened 16,599 articles and ultimately included 352 studies. The authors concluded that, in dogs and cats with infection, organ dysfunction should be required to diagnose sepsis. They also recommend formal illness-severity assessment using validated structured scores and measurements needed to identify organ dysfunction, including cardiovascular, renal, hepatic, coagulation, respiratory, neurologic, and metabolic changes. Suggested indicators include hypotension, hyperlactatemia, acute kidney injury, thrombocytopenia, hyperbilirubinemia, altered mentation, and ARDS-type respiratory dysfunction, although the authors note these markers still need prospective validation. (pubmed.ncbi.nlm.nih.gov)

Just as important is what the consensus deprioritizes. The review found inconsistent and generally weak evidence for SIRS as a prognostic marker, and said SIRS-based criteria can’t be recommended for identifying sepsis in clinical settings, particularly given poor specificity and limited support in cats. Instead, the group recommends incorporating organ dysfunction and illness-severity tools such as APPLE_fast, APPLE_full, SPI2, and SOFA-style approaches into clinical decision-making and research protocols. In the septic shock paper, the authors further recommend regular measurement of objective physiologic parameters, including heart rate, respiratory rate, and blood pressure in dogs, and core temperature and blood pressure in cats, for prognosis and monitoring. That practical pivot mirrors outside clinician education on the topic, which has emphasized that veterinary-specific definitions should improve consistency in how clinicians recognize severity and how researchers compare patients across studies, rather than simply borrowing human criteria that may not fit four-legged patients cleanly. (onlinelibrary.wiley.com)

Industry and clinician-facing commentary has already framed the change as a practical pivot rather than a semantic one. A March 2026 review from Critical.vet described the field as moving toward less emphasis on SIRS alone and more focus on organ dysfunction, shock phenotype, biomarkers, and individualized hemodynamic support. That interpretation lines up closely with the new consensus language, especially around serial reassessment and the idea that no single biomarker should stand alone. The septic shock paper likewise says worsening tissue oxygen delivery is associated with grave outcomes, but no single physiologic variable is universally predictive on its own. (critical.vet)

Why it matters: For veterinary professionals, the practical effect is a more disciplined framework for triage, monitoring, prognosis, and study design. In referral and emergency settings, the change may help teams distinguish uncomplicated infection from truly life-threatening sepsis, potentially improving escalation decisions and communication with pet parents. It also gives researchers and CE educators a more standardized vocabulary for enrollment criteria, outcomes reporting, and benchmarking across studies. The authors explicitly argue that overbroad criteria can contribute to overdiagnosis, unnecessary treatment, resource diversion, and even premature euthanasia based on perceived prognosis, so a more specific framework could have clinical and ethical implications as well. More broadly, the move to veterinary-specific definitions gives the profession a stronger foundation for shaping treatment recommendations and future studies around the realities of canine and feline patients, rather than relying mainly on human-adapted frameworks. (onlinelibrary.wiley.com)

The catch is that this is still an early framework, not a final bedside rule-out tool. The proposed organ dysfunction markers and septic shock manifestations are consensus-based and await prospective validation. The evidence base is also stronger for dogs than for cats, a limitation the authors acknowledge in both papers. Even so, the direction of travel is clear: veterinary sepsis is being reframed around organ dysfunction, structured scoring, and serial physiologic assessment, with septic shock recognized as a more severe, higher-mortality subset requiring intensified management. (onlinelibrary.wiley.com)

What to watch: Expect the next phase to focus on validating these criteria in retrospective and prospective multicenter datasets, with the eventual goal of more data-driven veterinary sepsis and septic shock definitions. (2025acvimforum.eventscribe.net)