What is Hemospray?
Hemospray, specifically the product TC-325 from Cook Medical, is an inert, proprietary blend of mineral powders engineered for endoscopic hemostasis. Delivered through a catheter during an endoscopic procedure, this powder provides a non-contact, non-thermal, and non-traumatic method of controlling severe bleeding within the gastrointestinal (GI) tract. It is particularly valuable for treating large or diffuse bleeding sites that are difficult to manage with conventional endoscopic tools. The spray can be applied to both upper and lower GI bleeding.
How Does Hemospray Work?
Once delivered via the catheter, the mechanism of Hemospray's action is quite straightforward and rapid. As the mineral powder makes contact with blood, it immediately absorbs water from the blood, causing the powder to swell and form a cohesive, adhesive gel. This gel creates a stable, mechanical barrier over the bleeding site, effectively tamponading the flow of blood. The powder also acts by concentrating platelets and clotting factors at the injury site, further accelerating the body's natural hemostatic processes. The resulting coagulated blood and gel mixture remains in place for approximately three days, after which it naturally sloughs off the mucosa and is eliminated from the GI tract.
The delivery system consists of three main components:
- A canister of TC-325 powder.
- A compressed carbon dioxide (CO2) propellant.
- A delivery catheter that is inserted through the endoscope's working channel.
Clinical Applications and Indications
Hemospray has proven to be a versatile tool in gastroenterology, used in a variety of situations where controlling bleeding is challenging. It is often employed in cases of:
- Peptic ulcers: Effective for controlling bleeding peptic ulcers, especially those with high-risk stigmata.
- Malignant GI bleeding: Particularly useful for patients with bleeding tumors, which often have friable surfaces and diffuse oozing that are difficult to treat with other methods.
- Post-procedural bleeding: Applied to control bleeding that occurs after endoscopic procedures like polypectomy, endoscopic mucosal resection (EMR), and sphincterotomy.
- Diffuse mucosal bleeding: Ideal for widespread bleeding, such as from radiation colitis or portal hypertensive gastropathy.
- Rescue therapy: Frequently used as a salvage method when conventional techniques like clipping or thermal therapy have failed to stop the bleeding.
While the manufacturer initially recommended against its use in variceal bleeding due to concerns about gas embolism, some studies have reported its safe and effective application in these cases as a bridging therapy.
Advantages of Hemospray
The non-contact application and rapid action of Hemospray offer significant advantages in treating active GI bleeding, especially in emergency scenarios. Key benefits include:
- Rapid Hemostasis: The powder achieves almost instantaneous hemostasis upon contact with blood.
- Non-Contact and Non-Traumatic: Since there is no physical contact with the bleeding site, there is no risk of further tissue trauma or perforation.
- Wide Surface Area Coverage: The aerosolized spray can cover large, diffuse bleeding surfaces or hard-to-reach areas that are not suitable for conventional methods.
- Ease of Use: The simplified delivery system can be deployed quickly and effectively, even by less experienced endoscopists in emergency situations.
- Bridging Therapy: It can stabilize a patient while preparations are made for a more definitive treatment, such as surgery or angiographic embolization.
Hemospray vs. Conventional Endoscopic Therapies
| Feature | Hemospray (TC-325 Powder) | Conventional Therapies (Clips, Thermal) |
|---|---|---|
| Mechanism | Mechanical barrier formed by powder absorbing blood, plus clotting factor concentration. | Mechanical compression (clips), thermal coagulation (heat probe, APC). |
| Contact Method | Non-contact application using a spray catheter. | Direct contact with the bleeding site is required. |
| Best For | Diffuse, large-area bleeding; bleeding from friable tumors; hard-to-reach areas. | Small, localized bleeding sites (e.g., discrete ulcers, visible vessels). |
| Rebleeding Risk | Higher risk when used as monotherapy, often requiring follow-up treatment. | Can be lower for high-risk lesions when used appropriately in combination therapy. |
| Ease of Use | Generally considered simple and quick to deploy, especially in emergent settings. | Requires more precise targeting and can be challenging in certain anatomies or in conditions with poor visualization. |
| Cost | One-time use canister can be expensive, but potentially reduces overall costs by avoiding more complex interventions or multiple endoscopies. | Variable depending on the device, but often requires multiple clips or applications. |
Safety Profile and Potential Adverse Events
While generally considered safe, some adverse events have been reported with Hemospray, though they are rare. A few case studies have noted potential side effects, including:
- Bowel Perforation: A serious but very rare complication, occurring in approximately 1% of patients in some trials.
- Endoscope Adherence: Transient sticking of the endoscope to the esophageal wall has been reported, but can usually be resolved with irrigation.
- Gas Embolism: This is a theoretical risk due to the CO2 propellant, but the low pressure of the delivery system makes it unlikely.
- Systemic Embolization: While laboratory tests and clinical studies have shown no evidence of systemic embolization, it remains a theoretical concern, particularly in patients with large vessel bleeding or fistulas.
Hemospray is contraindicated in patients who have a gastrointestinal fistula or are at a high risk for perforation.
The Role of Hemospray in the Future of GI Bleeding Management
Hemospray has established itself as an essential tool in the gastroenterologist's arsenal, particularly in emergency situations. Its ability to achieve rapid hemostasis in difficult-to-treat scenarios makes it a life-saving adjunct or rescue therapy. However, it is not a cure-all. Because of the risk of rebleeding, especially with high-risk lesions, current guidelines often recommend using Hemospray as a bridge to more definitive therapy rather than as a permanent monotherapy. The ease of application and efficacy, even with diffuse bleeding, continues to solidify its role in the management of GI bleeding. Research continues to explore its applications, refine its use, and compare its long-term outcomes to other established methods. For more information on hemostatic powders in gastrointestinal bleeding, a systematic review is available from the National Institutes of Health (NIH)(https://pmc.ncbi.nlm.nih.gov/articles/PMC9552790/).
Conclusion
In summary, Hemospray is a significant advance in endoscopic hemostasis, offering a rapid, non-contact solution for controlling difficult gastrointestinal bleeding. Its ability to form a mechanical barrier and concentrate clotting factors makes it uniquely suited for diffuse or large-area hemorrhages, particularly in emergency settings. While it is not a standalone solution for all types of bleeding, its efficacy as a bridging or rescue therapy is undeniable. By providing a quick, safe, and easy-to-use method for immediate bleeding control, Hemospray has improved patient outcomes and expanded the possibilities of endoscopic intervention.
