6.3 Intraoperative Medications

Managing Medications on the Sterile Field

The Certified Surgical First Assistant (CSFA) is frequently heavily involved in the preparation, labeling, handling, and application of medications directly on the sterile field. Absolute accuracy is required. Strict adherence to the "six rights" of medication administration (Right Patient, Right Drug, Right Dose, Right Route, Right Time, Right Documentation) is mandatory. Every single syringe, medicine cup, or basin containing a medication or fluid must be clearly labeled immediately upon receiving it from the circulator. An unlabeled fluid on the sterile field must be immediately discarded.

Anticoagulants and Reversal Agents

Anticoagulants prevent the formation of blood clots and are a staple in cardiovascular, peripheral vascular, and neurovascular surgeries.

Heparin Sodium

• Function: A potent, rapidly acting systemic anticoagulant. It works by binding to antithrombin III, inactivating thrombin and several other vital clotting factors.
• Surgical Use: Administered intravenously by the anesthesia provider approximately 3 to 5 minutes prior to cross-clamping a major blood vessel (e.g., the aorta, carotid artery, or prior to initiating cardiopulmonary bypass). This prevents devastating thrombosis in the stagnant blood pool.
• Irrigation Use: The CSFA frequently prepares heparinized saline on the sterile field (e.g., mixing 5,000 units of heparin into 500 mL of injectable normal saline). This solution is used via a syringe and specialized cannula to flush the lumens of arteries, veins, and synthetic grafts to prevent microscopic clot formation during the repair.

Protamine Sulfate

• Function: The specific, direct antagonist (reversal agent) for heparin.
• Surgical Use: Once the vascular anastomosis is complete, the clamps are removed, and blood flow is fully restored without leaks, anesthesia administers protamine sulfate intravenously. It binds strongly to heparin, neutralizing its anticoagulant effect and allowing the patient's normal clotting cascade to resume.

Antibiotics and Irrigation

Prophylactic antibiotics are standard in almost every surgical procedure to prevent surgical site infections (SSIs).

• Intravenous Prophylaxis: Typically administered by anesthesia within 60 minutes prior to the surgical incision (e.g., Cefazolin/Ancef). For tourniquet cases, it must be completely infused before the tourniquet is inflated.
• Topical Antibiotic Irrigation: The CSFA often prepares antibiotic irrigation solutions on the back table. Common agents include Bacitracin or Kanamycin/Cephalosporin mixtures. These are added to warm normal saline and used to aggressively irrigate the wound layers, flushing out debris and decreasing the bacterial load prior to wound closure.

Radiopaque Contrast Media

Contrast media are dense, iodine-based liquids injected into vessels, ducts, or hollow organs to render them highly visible under X-ray or fluoroscopy (C-arm).

• Common Agents: Omnipaque, Isovue, Hypaque, Visipaque.
• Surgical Use: Routinely used during operative cholangiograms to visualize the biliary tree, angiograms to verify vascular patency after a bypass, or retrograde pyelograms in urology.
• Handling Precautions: Because these agents contain significant amounts of iodine, patients must be rigorously screened for allergies to iodine or shellfish. Contrast agents present on the sterile field are clear liquids. They must be meticulously labeled to avoid disastrous confusion with saline or local anesthetics. Furthermore, when drawing contrast into a syringe, the CSFA must tap out every single air bubble; an air bubble injected into the biliary tree during a cholangiogram will show up as a dark spot on the X-ray, perfectly mimicking a retained gallstone.

Hemostatic Agents

While primary hemostasis is achieved physically with electrocautery, clips, or suture ties, topical hemostatic agents are crucial chemical adjuncts for controlling diffuse capillary oozing.

Emergency Drugs

The CSFA must be fundamentally aware of the emergency drugs kept on the "crash cart" and their primary indications.

• Epinephrine (Systemic): Administered intravenously during cardiac arrest (to stimulate myocardial contractility) or during severe anaphylactic shock (to cause bronchodilation and vasoconstriction).
• Atropine Sulfate: An anticholinergic used to treat symptomatic, severe bradycardia (a dangerously slow heart rate).
• Amiodarone or Lidocaine: Administered intravenously to treat life-threatening ventricular arrhythmias, such as ventricular tachycardia or ventricular fibrillation.
• Naloxone (Narcan): The specific opioid antagonist used to rapidly reverse the respiratory depression caused by narcotic analgesics (e.g., fentanyl, morphine).
• Flumazenil (Romazicon): The specific antagonist used to reverse the sedative effects of benzodiazepines (e.g., midazolam/Versed).

Steroids

Corticosteroids like Dexamethasone (Decadron) or Methylprednisolone (Solu-Medrol) are powerful anti-inflammatory agents. They are used intraoperatively to proactively reduce tissue inflammation and swelling. They are frequently requested in neurosurgery to decrease post-operative cerebral edema, or in otolaryngology (ENT) procedures to reduce airway swelling following aggressive intubation or surgical manipulation.