CST Practice Questions 2026: 8 Exam-Style Items Explained

Answer: C — A biological indicator containing Geobacillus stearothermophilus spores

A biological indicator is the only monitor that measures lethality directly. It carries a standardized population of highly resistant spores (Geobacillus stearothermophilus for steam), and no growth after incubation shows the cycle killed them. AAMI ST79 uses mechanical, chemical and biological monitors together, but only the BI shows kill rather than exposure to the right conditions.

• A. Mechanical monitoring shows the sterilizer reached its set parameters, but the readout can look normal while a pack was overloaded or held trapped air.
• B. External tape is a Class 1 process indicator. It only tells processed from unprocessed packages; it says nothing about conditions inside the pack.
• D. An internal integrator reacts to several critical parameters inside the pack and is useful for release decisions, but it still measures conditions, not whether organisms died.

Answer: A — A small tear in the outer wrapper at one corner, although the external indicator has changed color

Under event-related sterility a package stays sterile until something happens to it: a tear, moisture, a broken seal, a drop or poor storage. Any breach of package integrity makes the contents unsterile, and a changed external indicator does not rescue it, because that indicator only shows the package went through a sterilization process.

• B. With event-related sterility, shelf life depends on handling and storage, not on the calendar. A dry, intact, properly stored set without an expiration date can be used if facility policy follows that model.
• C. The expected color change is a normal finding. It confirms the set was processed, which is a requirement for use, not a reason to reject it.
• D. Load-control labeling is required so that a set can be traced and recalled. Having it is correct practice, not a defect.

Answer: A — Monofilament

A monofilament strand is a single solid filament, so it has no interstices to harbor bacteria and no capillary action to wick fluid along the strand. That is why monofilament sutures such as polypropylene or polydioxanone are preferred in contaminated or infected fields; they also pass through tissue with less drag.

• B. Braided strands have spaces between the filaments that can trap bacteria and wick fluid into the wound, which is the opposite of what the surgeon asked for.
• C. Twisted multifilament material (for example, cotton or twisted wire) still has spaces between strands and the same capillarity problem as braid.
• D. Coating reduces tissue drag and helps knots run down, but the core is still braided, so the interstices that can harbor bacteria remain.

Answer: B — Mixter right-angle clamp

A Mixter is a right-angle clamp: its jaws bend about 90 degrees, so the tip can be passed behind a duct or vessel to dissect it free and then grasp a tie and pull it around. That is exactly the step of isolating the cystic duct and cystic artery before they are ligated.

• A. An Ochsner (Kocher) has teeth at the tip and is meant for tough tissue such as fascia. It would tear a duct and cannot reach behind a structure.
• C. A Jennings is a mouth gag used in oral and throat surgery; it has no role in biliary dissection.
• D. A Babcock is an atraumatic grasping clamp for bowel, appendix or fallopian tube. It holds tissue but has no angled tip for dissecting behind a duct.

Answer: C — Lateral, with the operative side up

A pneumonectomy is usually done through a posterolateral thoracotomy, so the patient is placed in the lateral position with the operative side up; for a right pneumonectomy the patient lies on the left side. The table may be flexed at chest level to widen the intercostal spaces.

• A. Supine gives no access to the posterolateral chest wall; it suits a median sternotomy or anterior approaches.
• B. Lithotomy is used for perineal, gynecologic and urologic procedures, not chest surgery.
• D. Kraske (jackknife) is a prone position for rectal and pilonidal procedures.

Answer: B — Passive drainage along a soft, flat tube into the dressing by gravity and capillary action

A Penrose is a soft, flat, thin-walled tube that drains passively: fluid follows the drain out by gravity and capillary action and is absorbed by the dressing. It has no reservoir or suction, unlike closed active systems such as a Jackson-Pratt or Hemovac.

• A. Closed active drainage describes bulb or spring evacuators such as the Jackson-Pratt or Hemovac, not a Penrose.
• C. Irrigation needs a sump or double-lumen catheter system; a Penrose has a single flat lumen and no irrigation port.
• D. Closed gravity drainage into a bag describes tubes such as a Foley catheter or a T-tube connected to a bag; a Penrose drains into the dressing.

Answer: A — Dantrolene sodium

Unexplained tachycardia, rising end-tidal CO2 despite higher ventilation and masseter rigidity after a volatile agent and succinylcholine point to malignant hyperthermia. The triggers are stopped and dantrolene, 2.5 mg/kg IV repeated until signs subside, is the specific treatment per MHAUS. Fever is often a late sign, so the team does not wait for it before acting.

• B. Naloxone reverses opioids. Opioid excess causes respiratory depression and a slow rate, not rising CO2 with rigidity and tachycardia.
• C. Protamine reverses heparin and has no effect on the uncontrolled muscle calcium release that drives malignant hyperthermia.
• D. Flumazenil reverses benzodiazepines; it does nothing for a hypermetabolic crisis and can provoke seizures.

Answer: B — Common hepatic artery

The celiac trunk leaves the front of the aorta just below the diaphragm and divides into three branches: the left gastric, common hepatic and splenic arteries. The superior mesenteric, renal and inferior mesenteric arteries all arise directly from the abdominal aorta.

• A. The superior mesenteric artery arises directly from the front of the aorta, just below the celiac trunk at about L1.
• C. The renal arteries come directly off the sides of the aorta at about L1-L2.
• D. The inferior mesenteric artery arises directly from the front of the aorta at about L3, above the bifurcation.