Hemostasis in Surgery: Techniques and Products

By Dr. Zubair Khalid, DVM, MS, PhD · 2026-08-11

Key Takeaways

• Effective intraoperative hemostasis is critical to prevent impaired visualization, prolonged anesthetic recovery, and increased perioperative complications, with techniques categorized into mechanical, thermal, and chemical methods.
• Vessel diameter dictates the primary mechanical approach: <1 mm may require pressure or topical agents, 1-3 mm is amenable to ligation or hemoclips, and >3 mm necessitates suture ligation or vascular staplers.
• Topical hemostatic agents are classified as hemostats (promoting clot formation), sealants (creating a barrier), or adhesives (bonding tissue), and their efficacy is dependent on a dry field and prior mechanical control of active bleeding.
• Biologically active agents like fibrin sealants mimic the final coagulation cascade steps, forming a clot independent of patient status, while absorbable hemostats (gelatin, cellulose, collagen) provide a matrix for endogenous clot formation.
• Species-specific coagulation profiles (e.g., feline platelet characteristics, equine coagulation factors) may influence the perceived efficacy of topical agents that rely on endogenous hemostatic mechanisms.
• Rare anaphylactic reactions have been reported with hemostatic products containing bovine or porcine components, necessitating vigilance in patients with known hypersensitivity and careful consideration of product origin.

Effective intraoperative hemostasis is a foundational requirement for successful surgical outcomes across all veterinary species. Blood loss impairs visualization, prolongs anesthetic recovery, and increases the risk of transfusion dependence and perioperative complications. This article reviews the mechanical, thermal, and chemical methods available to the veterinary surgeon, with emphasis on the decision logic that guides product selection. It is written for practicing veterinarians who perform surgery in small animal, equine, or production animal practice and who seek a structured framework for matching hemostatic technique to tissue type, vessel caliber, and clinical context.

The physiology of hemostasis involves vascular spasm, platelet plug formation, coagulation cascade activation, and eventual fibrinolysis. Surgical hemostasis augments these native processes through physical occlusion, energy delivery, or topical procoagulant application. The choice among these approaches depends on vessel size, tissue fragility, access, and the availability of specialized equipment. A systematic review of hemostatic agents used in vascular surgery found that all studied agents achieved hemostasis significantly faster than manual compression alone, although comparative efficacy among agents varied with the clinical scenario Allotey et al., systematic review of hemostatic agents in vascular surgery.

At a Glance

Physiology of Surgical Hemostasis

The surgical approach to bleeding begins with identification of the source. Arterial hemorrhage demands mechanical control. Venous and capillary oozing may respond to pressure, topical agents, or thermal energy. The coagulation cascade culminates in thrombin-mediated conversion of fibrinogen to fibrin, and many commercial hemostatic products exploit this final common pathway. Fibrin sealants mimic the terminal steps of the cascade by combining purified human fibrinogen with human thrombin, sometimes supplemented with factor XIII and antifibrinolytics, to produce a stable clot independent of the patient's own coagulation status Jackson, fibrin sealants in surgical practice.

Platelet function and coagulation factor activity vary by species, and the veterinary surgeon should not assume that human-derived products behave identically across taxa. Feline platelets are larger and more variable in number than canine platelets, and equine coagulation profiles differ from those of small animals. These differences rarely alter the choice of mechanical technique but may influence the perceived efficacy of topical agents that depend on endogenous coagulation activity.

Mechanical Hemostasis

Direct Pressure and Packing

Firm digital pressure with gauze or laparotomy sponges remains the first maneuver for most bleeding. Pressure allows platelet aggregation and fibrin formation to proceed naturally. Packing is particularly useful for diffuse parenchymal bleeding or venous hemorrhage where suture placement would worsen the injury. The surgeon should maintain pressure for a minimum of three to five minutes before assessing whether additional measures are required.

Ligation and Suture Techniques

Suture ligation is the standard of care for vessels larger than 1 to 2 mm in diameter. Simple ligation with absorbable monofilament or braided suture suffices for most vessels. Transfixion sutures are indicated for large vessels, short stumps, or when the ligature may slip, such as the ovarian pedicle in an obese patient. Hemoclips offer rapid occlusion of vessels up to approximately 7 mm depending on clip size and manufacturer specifications. Metallic clips are permanent and should be used with caution near biliary or urinary structures where they may serve as a nidus for calculi.

Hemostatic Sponges and Dressings

Compressed gelatin, oxidized regenerated cellulose, and microfibrillar collagen provide a physical matrix that promotes platelet aggregation and clot formation. These agents are classified as absorbable hemostats and are most effective for capillary and small venous bleeding. A systematic review categorized hemostatic agents by primary mechanism of action and noted that absorbable agents are generally less costly than biologically active or dual-component products Allotey et al., systematic review of hemostatic agents in vascular surgery. Oxidized cellulose should be removed after hemostasis is achieved because it can retard healing and may potentiate infection.

Thermal Hemostasis

Electrocautery and Electrosurgery

Monopolar electrosurgery delivers current through the patient to a grounding pad, producing coagulation or cutting depending on waveform and power settings. It is effective for small vessels and diffuse oozing but carries risks of collateral thermal injury and unintended current pathways. Bipolar electrosurgery confines current between the forceps tips, reducing collateral damage and making it safer near nerves and delicate structures.

Vessel-Sealing Devices

Modern vessel-sealing devices combine bipolar energy with pressure to denature collagen and elastin, creating a permanent seal in vessels up to 7 mm. These instruments are widely used in laparoscopic and open surgery. A systematic review of energy devices in laparoscopic liver resection concluded that although these tools are efficient and reliable, they cannot replace the basic skills of sharp dissection, vascular control, and elective sealing of vessels Scatton et al., recommendations on energy devices for laparoscopic liver resection. The same principle applies in veterinary surgery: energy devices expedite hemostasis but do not substitute for sound dissection technique.

Argon Plasma Coagulation

Argon plasma coagulation delivers high-frequency current through ionized argon gas, producing superficial coagulation without tissue contact. It is useful for diffuse parenchymal bleeding, particularly in hepatic and splenic surgery. Depth of penetration is limited to 1 to 3 mm, which reduces the risk of deep thermal injury but also limits its utility for larger vessels.

Chemical and Topical Hemostasis

Classification of Topical Agents

Topical hemostatic products are classified as hemostats, sealants, or adhesives. Hemostats promote clot formation, sealants create a physical barrier over the bleeding surface, and adhesives bond tissue surfaces together Toro et al., TachoSil use in abdominal surgery. This distinction matters clinically: a sealant applied to an actively bleeding surface without prior hemostasis will simply be washed away.

Biologically Active Agents

Fibrin sealants combine concentrated fibrinogen and thrombin to form a clot independent of the patient's coagulation status. They are among the most effective topical agents and are particularly valuable in parenchymal bleeding, serosal surfaces, and patients with coagulopathy. The risk of viral transmission from plasma-derived products has been substantially reduced through donor screening and viral inactivation steps Jackson, fibrin sealants in surgical practice. Bovine thrombin preparations carry a rare risk of immunologic reactions, and products containing bovine or porcine components have been reported to trigger anaphylaxis in isolated cases Allotey et al., systematic review of hemostatic agents in vascular surgery.

Combination Products

Collagen or gelatin patches coated with human fibrinogen and thrombin combine a mechanical matrix with biologically active components. These dual agents have demonstrated faster hemostasis than single-component products in comparative studies, though at greater cost Allotey et al., systematic review of hemostatic agents in vascular surgery. In abdominal surgery, such patches have shown superiority to argon beam coagulation for achieving rapid intraoperative hemostasis, and their use has extended from open to laparoscopic procedures, although technical challenges in laparoscopy have limited adoption Toro et al., TachoSil use in abdominal surgery.

Preoperative Assessment and Planning

The selection of hemostatic technique begins before the first incision. A structured assessment of patient risk and procedural demands determines which methods should be available in the operating room.

Coagulation status warrants evaluation when the history suggests bleeding diathesis, when the procedure involves vascular-rich tissue, or when the patient has received anticoagulant or antiplatelet therapy. Screening should include platelet count, mucosal bleeding time or buccal mucosal bleeding time in dogs, and prothrombin time with activated partial thromboplastin time. Point-of-care viscoelastic testing provides additional information about clot formation kinetics and fibrinolysis when available. Breed-specific coagulopathies, such as von Willebrand disease in Doberman Pinschers and Scottish Terriers, may require specific factor assays before elective surgery.

Patient signalment and physiologic status modify the approach. Neonates have reduced hepatic synthetic capacity and lower concentrations of vitamin K dependent factors. Patients with hepatic insufficiency may have concurrent thrombocytopenia, platelet dysfunction, and reduced factor production. Hypothermia impairs platelet function and enzymatic coagulation cascades, so active warming during long procedures is both a hemostatic and a resuscitative measure.

The procedure itself dictates the minimum hemostatic armamentarium. A feline ovariectomy requires little beyond meticulous ligation. A splenic mass removal in a dog with hemoperitoneum demands preoperative crossmatch, vascular clamps, an aspirator, and immediate access to multiple hemostatic modalities. The surgeon should anticipate the tissue plane, the vascular density, and the consequences of failure for each step of the dissection.

Decision Guide for Intraoperative Bleeding

When unexpected bleeding occurs, the response follows a sequence instead of a random application of products. The first decision is whether the bleeding is from a discrete vessel or from a parenchymal or capillary bed. This distinction determines whether mechanical control or a topical agent is appropriate.

The surgeon must resist the urge to apply a hemostatic agent to a bleeding site that has not been visualized. Topical agents fail when placed over a stream of blood because the clot cannot form against flowing blood. The correct sequence is to control the source mechanically, dry the field, then apply a topical agent if needed to secure the surface.

Selection of Topical Hemostatic Agents

Topical agents are classified by their primary mechanism: physically absorbent materials, biologically active procoagulants, and combination products. The choice depends on the bleeding pattern, the tissue type, and the availability of products in the practice.

Absorbable gelatin, oxidized cellulose, and collagen sponges provide a physical matrix for clot formation. They are most effective for capillary oozing and venous bleeding from small vessels. Gelatin sponges absorb many times their weight in blood and expand, which is useful for packing but hazardous in confined spaces such as the spinal canal or around nerves where expansion can cause compression. Oxidized cellulose is bactericidal and works well in contaminated fields, but it is acidic and should not be left in contact with bone healing sites. Collagen sponges promote platelet aggregation and are particularly effective in heparinized patients.

Biologically active agents deliver concentrated procoagulant proteins to the bleeding surface. Fibrin sealants combine human fibrinogen with thrombin to form a fibrin clot independent of the patient's coagulation status. These products are the most effective tissue adhesives available and are biocompatible and biodegradable. They are valuable in parenchymal organs, vascular anastomoses, and areas where sutures would damage tissue. The main limitations are cost and the requirement for a dry field during application.

Combination products pair a physical matrix with biologically active components. One example is a collagen patch coated with human fibrinogen and thrombin, which has shown superiority to argon plasma coagulation for achieving rapid intraoperative hemostasis in hepatic surgery. These products are efficient but costlier than single-mechanism agents. They are particularly useful for large raw surfaces such as the liver bed after gallbladder removal or the thoracic cavity after partial lung lobectomy.

Species and Setting Considerations

The choice of hemostatic product and technique varies with species, production setting, and available equipment. In small animal practice, electrosurgery and vessel-sealing devices are standard. In equine surgery, the same devices are used but the larger tissue volumes and the need for standing procedures may favor ligation and topical agents. In food animal practice, cost and withdrawal considerations dominate the decision. A gelatin sponge may be appropriate for a calf with a lacerated liver, while a fibrin sealant would be economically impractical.

Product origin matters for safety. Agents containing bovine or porcine components carry a rare risk of anaphylactic reactions. This risk is relevant in patients with known hypersensitivity to mammalian products and in species where repeated exposure to bovine proteins is common. The risk of infectious disease transmission from human plasma-derived products has been reduced by donor screening and viral inactivation steps, but it has not been eliminated.

Regulatory oversight of hemostatic products differs between regions. Practitioners should verify that a product is licensed for veterinary use in their jurisdiction and should consult the WOAH terrestrial animal health standards where international movement of animals or products is involved. For food animals, the practitioner must confirm the withdrawal period for any product that could leave residues, using the current label or a national formulary.

Monitoring and Documentation

Hemostasis is not a single event but a process that continues through closure and into the recovery period. The surgeon should observe the secured site for at least one full respiratory cycle and one cardiac cycle before closing. In hypotensive patients, a vessel that appears dry at low blood pressure may bleed when perfusion is restored. Rechecking the site after volume resuscitation is a prudent step before abdominal or thoracic closure.

Postoperative monitoring focuses on the systemic consequences of blood loss and the integrity of the hemostatic site. Serial packed cell volume and total protein measurements detect ongoing hemorrhage, though they lag behind acute blood loss. Tachycardia, pale mucous membranes, prolonged capillary refill time, and progressive abdominal distension indicate active bleeding that requires re-exploration. In thoracic cases, a chest drain allows quantification of ongoing blood loss. The decision to re-operate is based on the rate of loss, the patient's cardiovascular status, and the failure of transfusion support to stabilize the patient.

Documentation should record the hemostatic methods used, the products applied, and the estimated blood loss. This information guides postoperative care, supports billing, and provides a record for medicolegal purposes. If a topical agent was used, the product name, lot number, and application site should be noted. Adverse reactions to hemostatic products, including suspected anaphylaxis, should be reported to the manufacturer and to the relevant pharmacovigilance authority.

Complications and Failure Modes

Topical hemostatic agents fail through predictable mechanisms. The most common is dislodgement, when the agent lifts from the wound bed as clot retracts or when the surgeon removes a laparotomy sponge before the agent has adhered. Detection is immediate: fresh bleeding appears at the application site, often with the agent floating free in the field. A second failure mode is incomplete activation. Gelatin and cellulose products require blood contact to swell and promote clot formation, when applied to a dry field or a surface with minimal bleeding, they remain inert and provide no hemostasis. The surgeon should confirm that the target vessel or parenchymal surface is actively bleeding before applying an absorbable agent.

Delayed bleeding after apparent hemostasis suggests inadequate vessel sealing instead of agent failure. This occurs when a vessel was sealed under low pressure or when a sealing device was fired across tissue containing a large vessel that retracted beyond the seal zone. The discriminating check is to inspect the seal line under magnification and to test the repair by transiently reducing mean arterial pressure or by applying gentle traction to the tissue.

Foreign body reactions and infection complicate the use of oxidized cellulose and some collagen products, particularly when large volumes are left in situ. Clinical signs appear days to weeks postoperatively and include seroma formation, draining tracts, or fever without an identifiable septic focus. Imaging may show a mass lesion at the prior surgical site. When a patient develops these signs after a procedure where a topical agent was used, the agent should be considered in the differential diagnosis before assuming surgical site infection.

Rare anaphylactic reactions to bovine or porcine constituents of hemostatic products have been reported, and the risk, while low, warrants vigilance in patients with known hypersensitivity to mammalian products Systematic review of hemostatic agents used in vascular surgery. The reaction typically begins within minutes of product application and presents as hypotension, tachycardia, and facial or laryngeal edema. Immediate removal of the agent, fluid resuscitation, and epinephrine are indicated.

Common Errors and Corrective Actions

Less experienced surgeons frequently apply topical agents before achieving adequate vascular control. A hemostatic sponge cannot stop arterial hemorrhage from a vessel that should have been ligated. The corrective sequence is to identify the bleeding source, control it mechanically, and use a topical agent only for diffuse parenchymal or capillary oozing.

A second recurring error is using an excessive volume of agent. Oxidized cellulose and gelatin products swell severalfold, and overpacking a cavity can compress adjacent structures or delay healing. The surgeon should use the smallest volume that covers the bleeding surface and should document the amount left in situ.

Electrosurgery errors include activating the handpiece before tip-tissue contact, which produces an arc that carbonizes tissue without sealing vessels, and using too high a power setting, which causes char that prevents deeper coagulation. The corrective action is to use the lowest effective power, keep the tip in light contact with tissue, and wipe char from the tip frequently.

Surgeons also misjudge when a vessel-sealing device is appropriate. These devices seal vessels up to a manufacturer-specified diameter, and using them on larger vessels invites seal failure. The surgeon must know the device specification and convert to suture ligation for vessels that exceed it.

Limitations of Current Evidence

Comparative data on hemostatic agents in veterinary surgery are sparse. Most evidence derives from human vascular and abdominal surgery, where topical agents have been shown to achieve hemostasis faster than manual compression, but head-to-head comparisons between agent classes remain limited Systematic review of hemostatic agents used in vascular surgery. The same review notes that dual agents combining biologically active and absorbable components are more efficient but costlier than single-component products, and that porcine or bovine constituents can trigger rare anaphylactic reactions.

Evidence for energy devices in parenchymal transection is similarly constrained. A systematic review of laparoscopic liver resection found that studies were heterogeneous and of low to very low quality, and concluded that energy devices cannot replace sharp dissection, vascular control, and elective sealing What kind of energy devices should be used for laparoscopic liver resection? Recommendations from a systematic review. Expert opinion still differs on whether blind transection or sharp dissection is preferable, and no firm recommendation can be made.

Fibrin sealants carry a theoretical risk of viral transmission from plasma-derived components, although modern donor screening and viral inactivation steps have substantially reduced this risk Fibrin sealants in surgical practice: An overview. Practitioners should verify the regulatory status and sourcing of any biologic agent used in their jurisdiction.

Referral and Escalation

Referral to a specialist is warranted when hemorrhage cannot be controlled with the techniques and products available, when a vessel-sealing device has failed on a named vessel, or when bleeding recurs after apparent hemostasis. Specialist consultation is also appropriate for elective procedures in highly vascular tissues, such as liver lobectomy or adrenalectomy, where preoperative planning for vascular control reduces intraoperative risk.

Laboratory involvement is indicated when bleeding is diffuse and disproportionate to the surgical site, suggesting an underlying coagulopathy. Preoperative coagulation testing, platelet count, and blood smear review should be performed before surgery in patients with a history of bleeding, and intraoperative consultation with a clinical pathologist may help identify von Willebrand disease, thrombocytopenia, or factor deficiencies.

Regulatory reporting obligations vary by jurisdiction. In the United States, adverse events associated with veterinary medical devices may be reported to the FDA, and the AVMA provides practice resources on reporting obligations AVMA practice resources. International practitioners should consult their national veterinary authority. For food animals, any hemostatic product used must be approved for the species, and withdrawal periods must be observed according to label and regulatory guidance.

Frequently Asked Questions

How do I choose a hemostatic agent when cost is a limiting factor?

Prioritize mechanical methods first. Direct pressure, packing, and suture ligation remain the most economical options and are effective for most bleeding. When a topical agent is required, absorbable gelatin or oxidized cellulose sponges are generally less expensive than biologically active products. The systematic review of hemostatic agents used in vascular surgery found that adhesives and dual agents were more efficient but costlier than agents with either biologically active or absorbable components alone. For parenchymal oozing where a fibrin sealant is ideal but unaffordable, gelatin sponge with manual compression often achieves acceptable hemostasis, albeit more slowly. Reserve high-cost products for situations where mechanical methods have failed or are anatomically impractical.

What should I do when vessel-sealing equipment is unavailable?

Return to fundamental techniques. Apply direct pressure to identify the bleeding source precisely, then use fine suture ligation or hemoclips for discrete vessels. For parenchymal transection, use a crushing clamp-crush technique with suture ligation of visible vessels before cutting. The review of energy devices for laparoscopic liver resection emphasizes that meticulous dissection and elective sealing of vessels remain the basic skills that energy devices cannot replace. In emergency situations, temporary packing with laparotomy sponges provides time to stabilize the patient, correct coagulopathy, and arrange additional resources. Do not attempt blind clamping, as this risks damage to adjacent structures. If bleeding persists despite these measures, consider early referral instead of prolonged intraoperative struggle.

How does hemostatic product selection differ between cats and dogs?

Cats have smaller vessel caliber and thinner tissue planes, making precise ligation more technically demanding. Topical hemostatic agents should be used sparingly in cats because their small body size amplifies the risk of foreign-body reactions and mass effect from retained products. Bovine-derived products carry a theoretical risk of immunologic reactions, and the review of TachoSil in abdominal surgery notes that immunologic reactions to bovine material, while rare, are a recognized concern. In cats, gelatin sponges are often preferred over collagen products due to faster absorption. Fibrin sealants are particularly useful in feline hepatic or renal biopsy sites where suture placement is difficult. For both species, ensure the product selected is appropriate for the tissue type and that the volume applied is proportionate to the bleeding surface.

What documentation is required after using hemostatic products?

Record the type and brand of each hemostatic agent used, the anatomic location, the approximate amount applied, and the method of application. Note whether the product was left in situ or removed after hemostasis was achieved. Document the estimated blood loss, duration of bleeding, and any adjunctive measures such as transfusion. This information is essential for postoperative monitoring, particularly if the patient develops delayed bleeding or signs of foreign-body reaction. For food animals, documentation of product use supports withdrawal interval decisions, and practitioners should consult WOAH terrestrial animal health standards and regional regulatory guidance regarding acceptable products and record requirements. Accurate records also inform future surgical planning for the same patient.

How should I explain unexpected intraoperative bleeding to a client?

Use clear, non-alarming language that conveys competence without minimizing the event. Explain that some bleeding is expected during surgery and that the surgical team has multiple methods to control it. Describe what was done, such as applying a topical sealant or placing additional sutures, and why it was necessary. Avoid technical jargon unless the client asks for detail. If a transfusion was required or the procedure was modified, state this plainly and outline the anticipated impact on recovery. The ACVS animal health resources provide client-oriented summaries of surgical procedures and expected outcomes that can supplement your explanation. Reassure the client about the monitoring plan for the immediate postoperative period and give specific signs to report, such as pale mucous membranes, lethargy, or swelling at the surgical site.

When should I refer a case for uncontrolled intraoperative hemorrhage?

Refer or escalate when bleeding persists despite correct application of mechanical, thermal, and topical methods, or when you lack the equipment or expertise to achieve vascular control safely. Specific triggers include bleeding from a vessel that cannot be isolated without risking adjacent structures, coagulopathy that does not correct with transfusion and medical therapy, and hemorrhage requiring ongoing resuscitation beyond available blood products. The consensus statement on perioperative blood management in cardiothoracic surgery underscores that comprehensive blood management requires a coordinated team approach, which may not be available in all settings. Before referral, stabilize the patient with packing, temporary closure, and volume support. Communicate clearly with the receiving facility about the bleeding source, products already used, and estimated blood loss. Early referral is preferable to prolonged attempts with inadequate resources.

Related Clinical & Scientific Guides

• Perioperative Antibiotic Prophylaxis: Timing and Selection
• Surgical Approaches to the Femur and Stifle
• Fracture Healing Assessment: Radiographic and Clinical Evaluation

References and Further Reading

• Systematic review of hemostatic agents used in vascular surgery.. 2021.
• TachoSil use in abdominal surgery: a review.. 2011.
• Fibrin sealants in surgical practice: An overview.. 2001.
• Drug, devices, technologies, and techniques for blood management in minimally invasive and conventional cardiothoracic surgery: a consensus statement from the International Society for Minimally Invasive Cardiothoracic Surgery (ISMICS) 2011.. 2012.
• Regenerative healing in fetal skin: a review of the literature.. 2007.
• What kind of energy devices should be used for laparoscopic liver resection? Recommendations from a systematic review.. 2015.
• American College of Veterinary Surgeons Animal Health Resources. American College of Veterinary Surgeons.
• MSD Veterinary Manual, Professional Edition. MSD Veterinary Manual.
• American Veterinary Medical Association Practice Resources. American Veterinary Medical Association.

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• Wound Debridement and Lavage Techniques
• Skin Flaps and Grafts in Reconstructive Surgery

This article is educational professional reference material for veterinary audiences. It is not a substitute for veterinary diagnosis, individual clinical judgment, current product labeling, or applicable regulatory requirements.