Overview
Definition:
Topical hemostats are agents applied directly to bleeding surfaces to promote clot formation and reduce blood loss
Energy devices utilize thermal or mechanical energy to achieve hemostasis by coagulating or vaporizing tissue
Selection depends on the nature of bleeding, tissue type, surgical site, and surgeon preference.
Clinical Significance:
Effective intraoperative hemostasis is crucial for minimizing blood loss, reducing transfusion requirements, shortening operative times, and preventing postoperative complications like hematoma formation and infection
Choosing the appropriate modality directly impacts patient outcomes and surgical success rates.
Principles Of Hemostasis:
Hemostasis involves a complex cascade of platelet aggregation and fibrin formation
Topical hemostats can act via mechanical, biological, or active mechanisms, while energy devices primarily rely on thermal denaturation of proteins and subsequent sealing of blood vessels
Understanding these principles aids in optimal device selection.
Topical Hemostats
Categories:
Mechanical hemostats (e.g., gelatin sponges, oxidized cellulose, collagen-based agents)
Biological hemostats (e.g., thrombin, fibrinogen-based sealants)
Active hemostats (e.g., procoagulant molecules)
Combination products.
Mechanism Of Action:
Gelatin sponges provide a scaffold for platelet adhesion and clot formation
Oxidized cellulose absorbs blood and forms a gelatinous mass that aids in clot stabilization
Collagen stimulates platelet aggregation
Thrombin converts fibrinogen to fibrin, directly promoting clot formation
Fibrin sealants create a fibrin mesh mimicking the final stage of coagulation.
Indications And Contraindications:
Generally indicated for oozing from broad surfaces, friable tissues, and as adjuncts to mechanical suture or ligature
Contraindicated in active arterial bleeding where rapid, forceful occlusion is needed
Specific product contraindications must be reviewed (e.g., potential for hypersensitivity reactions).
Examples And Uses:
Surgicel (oxidized regenerated cellulose) for general ooze
Gelfoam (gelatin sponge) for cystic cavities and general bleeding
Avitene (microcrystalline collagen) for platelet activation
Tisseel/Floseal (fibrin sealant) for parenchymal bleeding and tissue sealing.
Energy Devices
Types:
Electrosurgery (monopolar, bipolar)
Ultrasonic energy devices (e.g., Harmonic Scalpel)
Plasma-based devices
Laser energy.
Mechanism Of Action:
Electrosurgery uses high-frequency electrical current to generate heat, coagulating or cutting tissue
Ultrasonic devices use mechanical vibrations to shear and coagulate tissue
Plasma devices use ionized gas for cutting and coagulation
Lasers use focused light energy for ablation and coagulation.
Indications And Contraindications:
Effective for controlling pulsatile bleeding, ligating vessels, and creating precise cuts
Contraindicated in proximity to vital nerves or structures susceptible to thermal injury
Certain devices have limitations in moist environments or with specific tissue types
Electrosurgery requires careful consideration around pacemakers.
Advantages And Disadvantages:
Advantages include speed, efficacy in larger vessels, and ability to cut
Disadvantages include potential for collateral thermal damage, charring, smoke production, and interference with monitoring equipment (e.g., ECG)
Ultrasonic devices offer less collateral damage but can be slower for cutting.
Selection Criteria
Bleeding Characteristics:
Oozing from broad surfaces favors topical agents or gentle electrocoagulation
Pulsatile arterial bleeding may require vessel ligation, clips, or more potent energy devices
Venous bleeding is often controlled with topical agents or bipolar electrocautery.
Tissue Type And Location:
Friable tissues (e.g., liver, spleen) may benefit from mechanical hemostats or low-power energy settings
Highly vascular organs may require specialized techniques
Proximity to nerves, vessels, and organs dictates the choice to minimize thermal spread.
Surgical Procedure And Patient Factors:
Minimally invasive surgery may favor devices with smaller footprints and integrated cutting/coagulation
Patients with coagulopathies or on anticoagulation require careful consideration
Surgeon experience and preference are also significant factors.
Economic Considerations:
Cost of devices, disposables, and their impact on overall procedure cost is a factor in resource-limited settings
Some hemostatic agents are single-use, while energy devices have reusable components and associated maintenance costs.
Combined And Adjunctive Use
Synergistic Approaches:
Topical hemostats are frequently used in conjunction with energy devices
For instance, a fibrin sealant may be applied after electrocautery to reinforce seal and prevent re-bleeding.
Managing Difficult Bleeding:
In complex situations like significant parenchymal bleeding, a multi-modal approach is often employed, combining mechanical packing, topical agents, and carefully applied energy.
Postoperative Considerations:
The choice of hemostatic agent can influence postoperative management
Some agents may need to be removed or may dissolve over time
The risk of adhesion formation with certain agents also needs consideration.
Key Points
Exam Focus:
Understand the different classes of topical hemostats and energy devices, their mechanisms of action, and primary indications
Be prepared to discuss the rationale for choosing one over the other in specific surgical scenarios (e.g., liver resection vs
thyroidectomy).
Clinical Pearls:
Always read the manufacturer's instructions for use for specific hemostatic agents and energy devices
Recognize that effective hemostasis is a stepwise process, and often a combination of techniques is required
Adequate exposure and visualization are paramount.
Common Mistakes:
Over-reliance on a single modality
Inadequate control of pulsatile bleeding with passive agents
Excessive thermal damage to adjacent structures with energy devices
Failing to consider patient-specific factors like coagulopathy or proximity to vital organs.