CNOR

Preoperative testing follows evidence-based guidelines that match tests to the patient's conditions and the planned procedure. Routine testing without a clinical indication increases cost without improving outcomes. The nurse confirms that indicated results are available and reports abnormal values before the patient enters the operating room.

Test	TypicalIndications
Completebloodcount	Anticipatedsignificantbloodloss symptomsofanemia hematologicdisorders recentchemotherapy , , , ,
	proceduresonvascularorgans
Coagulationstudies(PT/INR ,	Anticoagulant therapy liver disease bleeding history high -bleeding-risk procedures planned , , , ,
aPTT)	neuraxialanesthesia
Basicmetabolicpanel	Renaldisease diabetes diureticorACEinhibitortherapy plannedcontrastadministration , , ,
Electrocardiogram	Known or suspected cardiovascular disease and higher-risk procedures in patients with cardiac risk ,
	factors
Chestradiograph	Acutepulmonarysymptomsorknowncardiopulmonarydiseasewitharecentchangeinstatus;little
	benefitinasymptomaticpatients
Pregnancytest	Offeredtoallpatientsofchildbearingpotential;manyfacilitiesrequireadocumentedresultwithina
	settimebeforeelectivesurgery
Typeandscreenor	Procedureswithameaningfullikelihoodoftransfusion
crossmatch

Value	TypicalReferenceRange	PerioperativeConcern
Potassium	3 .5–5 .0 mEq/L	Hypokalemiaorhyperkalemiaincreasestheriskofdysrhythmias
Hemoglobin Platelets	About 12–16 g/dL (women) 13– , 17g/dL(men) 150 ,000–450 ,000/mm³	underanesthesia;succinylcholineraisespotassiumfurther 1 Anemia reduces oxygen-carrying capacity and predicts transfusion Lowcountsincreasesurgicalandneuraxialbleedingrisk

Laboratoryvaluesthatcommonlydelayelectivesurgery(Continued)

Value	TypicalReferenceRange	PerioperativeConcern
INR	About 0 .8–1 .1 without	AnelevatedINRsignalsbleedingriskandmayrequirereversalor
	anticoagulation	delay
Glucose	70–99mg/dLfasting	Hyperglycemiaimpairsimmunefunctionandwoundhealingand
		raisesSSIrisk
Creatinine	About 0 .6–1 .2 mg/dL	Elevationindicatesimpairedrenalclearanceofanestheticsandother
		drugs

Standardized Risk Assessment Tools

Standardized tools quantify perioperative risk and guide optimization. The most commonly tested is the American Society of Anesthesiologists (ASA) Physical Status Classification.

Class	Defi nition	Example
ASAI	Anormalhealthypatient	Healthynonsmokerwithminimalalcoholuse
ASAII	Apatientwithmildsystemicdisease	Well -controlled hypertension or diabetes current smoker , ,
		pregnancy
ASAIII	Apatientwithseveresystemicdisease	Poorlycontrolleddiabetes COPD morbidobesity dialysis , , ,
ASAIV	Severesystemicdiseasethatisaconstant	Recentmyocardialinfarction sepsis severelyreducedejection , ,
	threattolife	fraction
ASAV	Amoribundpatientnotexpectedtosurvive	Rupturedabdominalaorticaneurysm
	withouttheoperation
ASAVI	A declared brain-dead patient whose organs	Organprocurement
	arebeingremovedfordonation

The suffix "E" is added for an emergency operation (for example, ASA III E).

Six predictors of major cardiac complications, one point each:

Stratifies venous thromboembolism risk from patient and

high-risk surgery, ischemic heart disease, heart failure,

procedure factors such as age, obesity, immobility,

cerebrovascular disease, insulin-treated diabetes, and serum

malignancy, prior VTE, and surgical duration. Higher scores

creatinine over 2 mg/dL.

call for more aggressive prophylaxis.

Stop-Bang

Screens for obstructive sleep apnea: Snoring, Tiredness,

Rates pressure injury risk from sensory perception, moisture,

Observed apnea, blood Pressure, BMI over 35, Age over 50,

activity, mobility, nutrition, and friction and shear. Lower scores

Neck over 40 cm, and male Gender. Three or more positive

mean higher risk and guide positioning surfaces and padding.

answers indicate high risk.

Identified risk factors guide optimization strategies that reduce complications. The nurse's role is to recognize unoptimized conditions, report them, and confirm that the plan was carried out.

Area	OptimizationStrategy
Cardiovascular	Control blood pressure and heart rate and treat active cardiac conditions Continue beta-blockers in .
	patients already taking them; starting a beta-blocker right before surgery requires careful timing and
	titration .
Pulmonary	Smokingcessationatleast4weeks andideally8weeks beforesurgery;treatactiverespiratory , ,
	infection;bronchodilatorsforreactiveairwaydisease;incentivespirometryteaching .
Glycemic	TargetahemoglobinA1cbelowabout8%forelectiveproceduresandaperioperativeinsulinplanfor
	patientswithdiabetes .
Nutritional	Serumalbuminbelow30g/dLindicatesmalnutrition anindependentriskfactorforcomplications;use . ,
	oral enteral orparenteralsupplementationdependingongutfunctionandtimeavailable , , .
Anemia	Evaluatehemoglobinbelow12g/dLinwomenor13g/dLinmen;treatthecause suchasoralorIViron ,
	forirondeficiency .

Managing Chronic Medications

Medication	UsualPerioperativeManagement
Beta-blockers calcium channel ,	Generallycontinued includingthemorningofsurgerywithasipofwater ,
blockers statins ,
ACEinhibitorsandARBs	Oftenheldthemorningofsurgerytoreduceintraoperativehypotension pertheanesthesiaplan ,
Warfarin	Typically stopped 5 days before surgery; bridging with heparin or low-molecular-weight heparin for
	highthromboticrisk
Directoralanticoagulants	Stoppedbasedonthespecificagent theprocedure'sbleedingrisk andrenalfunction , ,
Aspirinandotherantiplatelets	Individualized;aspirinforsecondarypreventionisoftencontinued anddualantiplatelettherapy ,
	aftercoronarystentingmustneverbestoppedwithoutcardiologyinput
Metformin	Usuallyheldthedayofsurgery;aftercontrast restartedonlywhenrenalfunctionisconfirmedper ,
	protocol
Sulfonylureas	Heldthemorningofsurgerytopreventhypoglycemia
Long-acting insulin	Commonly reduced to about 50–75% of the usual dose the night before or the morning of surgery ,
	perprotocol
Herbalsupplements	Stopped 1–2 weeks before surgery; garlic ginkgo ginseng and vitamin E affect bleeding St , , , , .
	John'swortaltersdrugmetabolism andephedraaffectscardiovascularstability ,

A patient who took a medication that should have been held, or who has not completed a required preoperative step, is reported to the surgeon and anesthesia professional before the patient leaves the preoperative area. The nurse never independently cancels a case or decides that a deviation is acceptable.

Preoperative Fasting

Fasting reduces gastric volume and the risk of pulmonary aspiration. Current ASA fasting guidance for healthy patients undergoing elective procedures allows clear liquids up to 2 hours before anesthesia, breast milk up to 4 hours, infant formula and a light meal up to 6 hours, and fried or fatty foods and meat up to 8 hours or more. Confirm the time and content of the last intake and report any deviation to the anesthesia professional.