4.3 Surgical Pharmacology
Key Takeaways
- The six rights of medication are right patient, right drug, right dose, right route, right time, and right documentation.
- AST standards require ALL medications and solutions on and off the sterile field to be labeled, including syringes, medicine cups, and basins.
- When receiving a drug, the surgical technologist repeats the name and strength back to the circulator and labels it immediately.
- Epinephrine is added to local anesthetics (commonly 1:100,000 or 1:200,000) as a vasoconstrictor to prolong the block and reduce bleeding; it is avoided in digits, nose, ears, and penis.
- Lidocaine's maximum dose is about 4.5 mg/kg plain and 7 mg/kg with epinephrine; topical hemostatic agents include Gelfoam, Surgicel, Avitene, and thrombin.
Drug Categories Used in Surgery
The Surgical Pharmacology sub-domain is small (about 7 questions) but very predictable. Know the major categories and a flagship example of each:
| Category | Purpose | Examples |
|---|---|---|
| Local anesthetics | Block sensation in a region while the patient is awake | Lidocaine, bupivacaine (Marcaine), procaine |
| General anesthetics | Produce unconsciousness | Propofol, sevoflurane, nitrous oxide |
| Hemostatic agents | Control bleeding | Gelfoam, Surgicel, Avitene, thrombin, bone wax |
| Antibiotics | Prevent or treat infection | Cefazolin (Ancef), vancomycin |
| Contrast media | Visualize structures on imaging | Omnipaque, Hypaque (iodinated) |
| Anticoagulants / reversal | Prevent or reverse clotting | Heparin; protamine sulfate reverses heparin |
| Diagnostic dyes | Mark tissue or test patency | Methylene blue, indigo carmine, lugol's |
Anesthetics — Local vs. General
Local anesthetics end in -caine and work by blocking sodium channels so nerves cannot transmit pain. Bupivacaine (Marcaine) lasts longer than lidocaine but is more cardiotoxic. General anesthetics render the patient unconscious and are managed by anesthesia; the tech should still recognize propofol (the white "milk of amnesia" induction agent) and the inhaled agents.
Hemostatic Agents
Hemostatic agents are a favorite exam topic. Absorbable gelatin (Gelfoam) is often soaked in thrombin for added clotting power. Oxidized cellulose (Surgicel) and microfibrillar collagen (Avitene) also promote clotting. Bone wax is a mechanical agent that physically seals bleeding bone. Note that protamine is NOT a topical hemostatic agent — it is a heparin antagonist.
Epinephrine With Local Anesthetic
Epinephrine is frequently added to local anesthetics as a vasoconstrictor. By constricting vessels at the injection site, epinephrine:
- Prolongs the duration of the anesthetic block
- Reduces bleeding in the surgical field
- Slows systemic absorption, lowering the risk of anesthetic toxicity
Common concentrations are 1:100,000 and 1:200,000. The classic exam trap: epinephrine-containing local anesthetic must never be injected into areas supplied by end arteries — the fingers, toes, nose, ears, and penis — because the vasoconstriction can cause tissue death (ischemic necrosis).
Dosage Awareness
| Drug | Max Dose (Approx.) |
|---|---|
| Lidocaine (plain) | 4.5 mg/kg (up to ~300 mg) |
| Lidocaine with epinephrine | 7 mg/kg (up to ~500 mg) |
A percent solution tells you concentration: 1% = 10 mg/mL and 2% = 20 mg/mL. So 10 mL of 1% lidocaine = 100 mg. Recognizing these conversions helps the tech catch a dosing error.
Safe Medication Handling on the Sterile Field
The surgical technologist follows the six rights of medication administration every time a drug crosses the sterile field:
- Right patient
- Right drug
- Right dose
- Right route
- Right time
- Right documentation
AST Labeling Standard
Per AST Standards of Practice, all medications and solutions, both on and off the sterile field, must be labeled — this includes syringes, medicine cups, and basins. Unlabeled medication on the field must be discarded. The accepted handoff sequence is:
- The circulator shows the vial and states the drug name, strength, and expiration.
- The surgical technologist repeats the name and strength back (closed-loop verification).
- The drug is delivered to the field and the tech labels the container immediately.
- When passing to the surgeon, the tech states the drug name and strength aloud again.
This verbal confirmation at every step is the core defense against wrong-drug and wrong-dose errors in a sterile environment where original packaging is no longer present.
Antibiotics, Contrast Media, and Anesthesia Concepts
Prophylactic Antibiotics
Cefazolin (Ancef), a cephalosporin, is the most common surgical prophylactic antibiotic. The standard rule the tech must support: give the prophylactic antibiotic within 60 minutes before incision so tissue levels are therapeutic during the case. Vancomycin is used for patients with a beta-lactam allergy or MRSA risk and is infused slowly to avoid "red man syndrome." The tech should always ask about drug allergies before passing antibiotic-soaked materials.
Contrast Media
Contrast media make structures visible on imaging. Iodinated agents (Omnipaque, Hypaque) are used for cholangiograms and vascular studies, so the team must verify the patient has no iodine/shellfish allergy and no renal contraindication before use. The tech keeps contrast clearly labeled and separated from saline and local anesthetic on the field.
Anesthesia Concepts
General anesthesia progresses through four stages: (1) induction/analgesia, (2) excitement/delirium, (3) surgical anesthesia (the operative plane), and (4) overdose/medullary paralysis (to be avoided). The OR should be quiet during induction because hearing is the last sense lost and stimulation can cause laryngospasm. Malignant hyperthermia (MH) is a rare, life-threatening reaction to inhaled agents and succinylcholine, treated with dantrolene; every OR keeps an MH cart stocked.
Drug Forms and Routes
| Route | Abbreviation | Surgical Example |
|---|---|---|
| Intravenous | IV | Antibiotics, propofol |
| Intramuscular | IM | Some pre-medications |
| Topical | — | Surgicel, thrombin spray |
| Subcutaneous/local infiltration | SubQ | Lidocaine with epinephrine |
| Inhalation | — | Sevoflurane, nitrous oxide |
Understanding the route confirms the right route of the six rights and tells the tech how a drug will be delivered — a topical hemostatic is applied to tissue, never injected, while a local anesthetic is infiltrated, not poured.
Why is epinephrine commonly added to a local anesthetic such as lidocaine?
According to AST standards, what must be done with every medication and solution on the sterile field?
Which of the following is NOT a topical hemostatic agent?
How many milligrams of lidocaine are in 10 mL of a 1% lidocaine solution?