Gastrointestinal (GI) endoscopy has become an invaluable tool for diagnostic and therapeutic intervention in small animal internal medicine. While these procedures are minimally invasive compared with exploratory surgery, they are far from benign from an anesthetic perspective. Patients undergoing upper and lower GI endoscopy frequently present with systemic illness, fluid and electrolyte derangements, and a range of comorbidities that elevate anesthetic risk. For veterinary professionals, the challenge lies not only in delivering safe anesthesia for the procedure itself, but in anticipating and mitigating the risks that accompany these cases.
Unique Challenges of Veterinary Endoscopy Anesthesia
Endoscopic procedures present unique challenges based on the techniques needed to be able to perform good diagnostics or treatments. Even in relatively straightforward cases, anesthetists must account for airway manipulation, patient positioning, and the potential for regurgitation and aspiration. Upper GI endoscopy, in particular, necessitates a secured airway and careful control of ventilation.
A key aspect of performing a thorough upper endoscopic exam involves inflation of the stomach with air. A delicate balance has to exist to allow the internist to visualize all areas of the stomach and proximal duodenum while preventing ventilation challenges for the anesthetist. Changes in intrathoracic pressure, potential hypoventilation, and hypercapnia require close monitoring and readiness to provide positive pressure ventilation. Continuous monitoring of end-tidal CO₂ and oxygenation is considered essential, as rapid changes may occur during insufflation of the GI tract or increased anesthetic depth.
These challenges are compounded when procedures are prolonged or combined with biopsies and lower GI endoscopy (colonoscopy), increasing total anesthetic time and cumulative risk. As with upper GI endoscopy, lower GI endoscopy requires insufflation to visualize the mucosa appropriately. This air can travel all the way to the stomach, where it can accumulate. Pain, hypoventilation, and even a vagal event can be seen if a severely distended stomach isn’t immediately deflated by passing an orogastric tube.
Anesthesia Risks in Dogs and Cats Undergoing Endoscopy
Despite significant advances in monitoring and pharmacology, anesthesia-related mortality in dogs and cats remains higher than in human medicine, with reported risks of approximately 0.17% in dogs and 0.24% in cats. More recent literature continues to emphasize that perianesthetic death, while uncommon, is a persistent and multifactorial concern, particularly in patients with higher ASA physical status, extremes of age or weight, or underlying disease. Importantly, many of the patients referred for GI endoscopy fall into these higher-risk categories.
Endocrine disease, such as diabetes mellitus or hyperadrenocorticism, may predispose patients to altered glucose homeostasis, delayed gastric emptying, and impaired immune function. These factors increase the risk of aspiration, infection, and hemodynamic instability. Careful pre-anesthetic assessment, including recent bloodwork and stabilization of metabolic parameters, is essential.
Similarly, patients with orthopedic disease, particularly geriatric animals with osteoarthritis, may not initially appear high risk but often require thoughtful positioning and analgesic planning to prevent perioperative pain and post-procedural discomfort. Positioning for endoscopy can exacerbate joint discomfort or restrict ventilation if not managed appropriately.
Managing Anesthesia in Patients With Comorbidities
Patients with cardiac disease present one of the most significant anesthetic challenges. These patients require careful drug selection and hemodynamic monitoring. The anesthetic plan must minimize myocardial depression, avoid significant changes in systemic vascular resistance, and allow rapid adjustment of anesthetic depth. Even relatively short procedures can precipitate decompensation in these patients if preload, afterload, or heart rate are not carefully managed. Continuous ECG monitoring, blood pressure measurement, and, when indicated, advanced monitoring techniques are strongly recommended.
The presence of multiple comorbidities further amplifies complexity. For example, a diabetic dog with concurrent cardiac disease undergoing endoscopy for chronic vomiting presents intersecting risks: aspiration, hypoglycemia, and cardiovascular instability. These are not uncommon scenarios in referral practice and highlight the importance of individualized anesthetic protocols rather than standardized endoscopy protocols. Literature on medication errors in veterinary anesthesia also reinforces the risks inherent in managing complex cases with multiple drugs and rapid decision-making, emphasizing the need for structured protocols, communication, and vigilance.
Pre-Anesthetic Planning and Protocol Selection
Effective anesthetic planning begins well before the patient enters the endoscopy room. A thorough review of history, diagnostic findings, and current medications is foundational. Risk stratification using ASA classification provides a useful framework but should be supplemented with clinical judgment. Pre-anesthetic stabilization can significantly reduce peri-anesthetic complications.
Fasting protocols may need modification in patients at risk of hypoglycemia or those with delayed gastric emptying, balancing aspiration risk with metabolic needs. Drug selection should be guided by the patient’s comorbidities and the anticipated duration and invasiveness of the procedure. Multimodal approaches that minimize reliance on any single agent can help reduce adverse effects.
For example, opioid-based premedication combined with titratable induction agents such as propofol or alfaxalone allows for smoother induction and rapid airway control. Maintenance with inhalant anesthesia remains standard, but total intravenous anesthesia (TIVA) may be advantageous in select cases. Regardless of protocol, the ability to rapidly adjust anesthetic depth and support ventilation is critical.
The Role of Veterinary Anesthesiologists in Endoscopy
In this context, collaboration with a board-certified veterinary anesthesiologist can be incredibly valuable. These specialists bring advanced training in pharmacology, physiology, and critical care, enabling them to design nuanced anesthetic plans for complex patients. Their involvement is particularly valuable in cases with significant comorbidities, prior anesthetic complications, or anticipated procedural challenges.
Beyond individual case management, anesthesiologists contribute to the development of standardized protocols, staff training, and quality improvement initiatives that reduce overall morbidity and mortality. Most notably, the anesthesiologist helps the internist focus on the procedural goals for the patient and not on the anesthesia monitor. This collaborative effort further helps decrease anesthesia time, improving safety for the patient.
Improving Outcomes With Veterinary Endoscopy Anesthesia
Successful anesthesia for GI endoscopy hinges on recognizing that these are often medically complex patients undergoing deceptively routine procedures. The focus should extend beyond simply maintaining an adequate plane of anesthesia to actively supporting the patient’s underlying physiology throughout the peri-anesthetic period.
When clinicians take the time to thoughtfully assess risk, tailor anesthetic protocols, and engage appropriate expertise, they shift the approach from reactive to proactive care. This mindset not only reduces the likelihood of complications but also elevates the overall standard of care, ultimately leading to safer procedures and better outcomes for both dogs and cats undergoing GI endoscopy.
If your patient needs a GI endoscopy or has underlying conditions that increase anesthesia risk, contact our team to ensure safe, carefully managed care from start to finish.
Photo by C Perret on Unsplash used with permission under the Creative Commons license for commercial use 04/14/2026