Preoperative Care and Informed Consent

Medical-Surgical · Perioperative / Pre & Post-Op·Updated 2026-10-28

What it is

Preoperative care identifies risks and prepares the client so surgery proceeds safely. Informed consent is a process: the surgeon who performs the procedure explains its nature, risks, benefits and alternatives; the nurse witnesses the signature and confirms that the client is competent, informed and signing voluntarily. Anesthesia suppresses protective airway reflexes, so a full stomach raises the risk of pulmonary aspiration; that mechanism drives the fasting rules.

What the NCLEX focuses on

Valid consent requires a competent adult (or legal guardian, or emancipated minor), adequate disclosure, understanding and a voluntary choice, signed before any sedating premedication.
If the client asks about the technique or does not understand, the nurse notifies the surgeon before the form is signed; the nurse does not explain the procedure.
In a life-threatening emergency with no one able to consent, treatment proceeds under implied consent and the circumstances are documented.
Clients with limited English proficiency receive information through a qualified medical interpreter, not a family member.
Medications: anticoagulants and antiplatelets are stopped as the surgeon directs (warfarin typically 5 days before); beta blockers are continued; the prescriber adjusts insulin for the fasting period; ginkgo, garlic and ginseng supplements increase bleeding and are reported.
Latex allergy: ask about reactions to bananas, avocados, kiwi and chestnuts (cross-reactivity).
Remove nail polish and artificial nails (pulse oximetry), jewelry and dentures; the surgeon marks the site with the client awake, and a time-out confirms client, procedure and site.

Priority nursing actions

Verify the client's identity with two identifiers, the procedure, the site and allergies.
Confirm a signed, witnessed consent before giving preoperative sedation; notify the surgeon of unanswered questions.
Confirm the fasting time, check blood glucose in clients with diabetes, and report abnormal results (potassium, glucose, hemoglobin, platelets, INR, pregnancy test).
Give or hold morning medications exactly as prescribed, with a sip of water.
Teach turning, coughing, deep breathing, incentive spirometry and leg exercises, and confirm learning with teach-back.
Complete the checklist, have the client void, give the premedication, then raise the side rails and keep the client in bed.

Numbers to know

Item	Minimum fast or normal value	Why it matters
Clear liquids (water, pulp-free juice, black coffee, clear tea)	2 hours	Leave the stomach quickly
Breast milk	4 hours	Empties faster than formula
Infant formula or nonhuman milk	6 hours	Protein and fat slow gastric emptying
Light meal (toast and clear liquid)	6 hours	Solids need more time to empty
Fried or fatty foods, meat	8 hours or more	Fat delays gastric emptying the most
Potassium	3.5 to 5.0 mEq/L (3.5 to 5.0 mmol/L)	Abnormal values cause dysrhythmias under anesthesia

Common exam traps

Choosing to explain the surgical technique to the client: wrong because disclosure is the surgeon's legal duty; the nurse notifies the surgeon.
Choosing to obtain the signature after the preoperative opioid or benzodiazepine: wrong because sedation invalidates consent.
Choosing to hold a daily beta blocker the morning of surgery: wrong because abrupt withdrawal causes rebound tachycardia and hypertension.
Choosing a family member as interpreter: wrong because accuracy and confidentiality require a qualified medical interpreter.
Choosing to shave the operative site with a razor: wrong because skin nicks raise infection risk; hair is removed only if needed, with clippers.

What to teach

Follow the fasting times exactly and take only the medications the surgeon or anesthesia team approved, with a sip of water.
Stop herbal supplements and report anticoagulant or antiplatelet use as instructed.
Shower with the prescribed antiseptic soap and do not shave near the surgical site.
Practice incentive spirometry, deep breathing, splinting and leg exercises before surgery.

Client handout: Getting Ready for Surgery (nurse guide and printable patient handout).

Try 2 NCLEX-style questions on this topic

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Question 1 · QID 37E817D0

A client scheduled for surgery asks the nurse a detailed question about the specific surgical technique that will be used. Which action is most appropriate?

Select the best answer.

A. Explain the general purpose of the operation and ask the client to discuss the specific technique with the surgeon later
B. Explain the surgical technique using the nurse's knowledge of how the procedure is usually performed
C. Witness the consent signature first, then document the question for the surgeon to address before transport to the operating room
D. Notify the surgeon of the client's question before the consent process proceeds

Question 2 · QID 3CED56B8

A client asks the nurse why they cannot eat a full meal in the hours before surgery. For each possible explanation, indicate whether it is accurate or inaccurate.

For each explanation of preoperative fasting, indicate whether it is accurate or inaccurate.

	Accurate	Inaccurate
Fasting prevents the client from feeling hungry during the procedure
Fasting has no relationship to anesthesia safety
Fasting reduces the volume of stomach contents and lowers the risk of aspiration during anesthesia
Fasting is simply a hospital policy with no specific physiologic reason

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Sources

Harding MM, Kwong J, Hagler D, Reinisch C. Lewis's Medical-Surgical Nursing: Assessment and Management of Clinical Problems. 12th ed. Elsevier; 2023.
American Society of Anesthesiologists. Practice Guidelines for Preoperative Fasting and the Use of Pharmacologic Agents to Reduce the Risk of Pulmonary Aspiration: Application to Healthy Patients Undergoing Elective Procedures. Anesthesiology. 2017;126(3):376-393.
The Joint Commission. Universal Protocol for Preventing Wrong Site, Wrong Procedure, and Wrong Person Surgery.

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