1.1 Preoperative Patient History, Physical Assessment & Comorbidity Stratification
Key Takeaways
- The ASA Physical Status Classification System categorizes perioperative mortality risk, ranging from ASA I (healthy) to ASA VI (brain-dead organ donor), with an 'E' modifier appended for emergency procedures.
- Airway risk assessment requires evaluating Mallampati classes (Classes III and IV predict difficult intubation) and thyromental distance (< 6 cm indicates a difficult airway).
- Functional capacity assessed at < 4 METs (inability to climb two flights of stairs without stopping) correlates directly with elevated perioperative cardiac morbidity.
- A STOP-BANG score of 5 to 8 indicates high risk for obstructive sleep apnea (OSA), requiring preoperative difficult airway setup and postoperative opioid-sparing protocols.
- In pediatric patients, an upper respiratory infection (URI) within 2 to 4 weeks prior to surgery increases the risk of perioperative laryngospasm and bronchospasm by up to 7-fold.
Preoperative Patient History, Physical Assessment & Comorbidity Stratification
The preoperative assessment is the foundation of perioperative nursing care. Its primary objective is to evaluate the patient’s baseline physiological status, identify coexisting medical conditions, quantify surgical and anesthetic risk, and formulate an individualized perioperative plan of care. A thorough preoperative assessment mitigates preventable intraoperative complications, optimizes post-anesthetic recovery, and reduces surgical site infections (SSIs) and perioperative mortality.
Comprehensive Health History & Anesthetic Screening
A targeted health history must be obtained prior to transferring any patient to the operating suite. The perioperative nurse gathers historical data through structured interview, medical record review, and interprofessional consultation. Key historical domains include:
- Chief Complaint & Surgical Indication: Verification of the proposed surgical procedure, surgical site, and operative side against the patient's statement and informed consent.
- Past Medical & Surgical History: Identification of chronic illnesses including hypertension, coronary artery disease (CAD), heart failure, chronic obstructive pulmonary disease (COPD), asthma, diabetes mellitus, renal insufficiency, hepatic dysfunction, and stroke.
- Prior Anesthetic Experience: Documentation of previous anesthetic exposures, focusing on adverse reactions such as postoperative nausea and vomiting (PONV), difficult endotracheal intubation, prolonged neuromuscular blockade (suggestive of pseudocholinesterase deficiency), and unexplained intraoperative hyperthermia or muscle rigidity suggestive of malignant hyperthermia (MH).
- Family Anesthetic History: Unexplained intraoperative deaths, unexpected intensive care unit (ICU) admissions, or a family history of MH or muscle disorders (e.g., central core disease, King-Denborough syndrome).
Physical Assessment & Airway Risk Stratification
Physical evaluation focuses on organ systems vulnerable to anesthetic agents and surgical stress. Systems assessment must establish clear clinical baselines:
Airway Evaluation
Airway management is a critical nursing assessment priority. The Mallampati classification predicts difficult endotracheal intubation by assessing visual structures of the oral cavity while the patient sits upright, opens their mouth wide, and protrudes their tongue without phonation:
| Mallampati Class | Visualized Structures | Intubation Risk |
|---|---|---|
| Class I | Soft palate, fauces, uvula, anterior and posterior pillars | Normal / Low |
| Class II | Soft palate, fauces, uvula visible | Low |
| Class III | Soft palate, base of uvula visible | Moderate / Difficult |
| Class IV | Hard palate only visible; soft palate not visualized | High / Very Difficult |
Additional airway risk indicators include:
- Thyromental Distance: Measured from the thyroid notch to the mental protuberance with the neck fully extended. A distance of less than 6 cm (approximately 3 fingerbreadths) indicates a recessed mandible and a high probability of difficult laryngeal visualization.
- Cervical Spine Mobility: Inability to extend the neck past 35 degrees (common in rheumatoid arthritis or ankylosing spondylitis).
- Interincisor Gap: Maximum mouth opening of less than 3 cm (2 fingerbreadths) impedes laryngoscope insertion.
Cardiovascular & Respiratory System Assessment
- Cardiovascular: Auscultation of heart sounds (detecting S3/S4 gallops or new murmurs), evaluation of peripheral edema, baseline blood pressure in both arms, and apical pulse rhythm. Patients with active cardiac conditions (unstable angina, recent myocardial infarction within 30 days, decompensated heart failure, severe aortic stenosis) require immediate cardiology clearance.
- Respiratory: Auscultation of breath sounds across all pulmonary fields. Document baseline wheezing, rales, or rhonchi. Active upper respiratory infections (URIs) in pediatric patients within 2 to 4 weeks prior to surgery increase the risk of perioperative laryngospasm, bronchospasm, and hypoxemia by up to 7-fold.
Comorbidity Stratification Models
Perioperative nurses utilize standardized scoring systems to categorize patient risk and communicate acuity across the surgical team.
1. ASA Physical Status Classification System
The American Society of Anesthesiologists (ASA) classification system categorizes a patient’s physiological state and overall operative risk:
- ASA I: A normal, healthy patient. Non-smoker, minimal/no alcohol use, normal BMI.
- ASA II: A patient with mild systemic disease without substantive functional limitations. Examples: Controlled hypertension, controlled diabetes mellitus, BMI 30.0–39.9, active cigarette smoker, social alcohol drinker.
- ASA III: A patient with severe systemic disease with substantive functional limitations. Examples: Poorly controlled hypertension or diabetes, COPD, morbid obesity (BMI ≥ 40), active hepatitis, alcohol dependence, end-stage renal disease (ESRD) on regularly scheduled dialysis, pacemaker, or history (> 3 months) of myocardial infarction (MI), cerebrovascular accident (CVA), or coronary artery stent placement.
- ASA IV: A patient with severe systemic disease that is a constant threat to life. Examples: Recent (< 3 months) MI, CVA, or TIA; ongoing cardiac ischemia or severe valve dysfunction; severe reduction of ejection fraction (EF < 30%); sepsis; disseminated intravascular coagulation (DIC); or ESRD not undergoing scheduled dialysis.
- ASA V: A moribund patient who is not expected to survive without the operation. Examples: Ruptured abdominal/thoracic aortic aneurysm, massive trauma, intracranial hemorrhage with mass effect.
- ASA VI: A declared brain-dead patient whose organs are being removed for donor purposes.
- Emergency Modifier ('E'): Appended to any ASA class (e.g., ASA III-E) when delay in treatment would significantly increase the threat to life or body part.
2. Functional Capacity & Metabolic Equivalents of Task (METs)
Functional capacity is a strong independent predictor of perioperative cardiac events. It is quantified using Metabolic Equivalents of Task (METs):
- < 4 METs (Poor): Inability to walk 1 to 2 blocks on level ground at 2 to 3 mph, or perform light house chores. Climbing two flights of stairs without stopping requires approximately 4 METs. Patients unable to achieve 4 METs represent an elevated risk for perioperative myocardial ischemia.
- 4–7 METs (Moderate): Ability to climb two flights of stairs, walk up a hill, or scrub floors.
- > 7–10 METs (Excellent): Participation in strenuous sports (swimming, singles tennis, basketball).
ACC/AHA guidelines state that if a patient can achieve ≥ 4 METs of activity without cardiac symptoms, further invasive cardiac testing is rarely indicated prior to non-cardiac surgery.
3. STOP-BANG Questionnaire for Obstructive Sleep Apnea (OSA)
Screening for OSA is mandatory to prevent postoperative airway obstruction and hypoxemia:
- Snoring (loud snoring)
- Tiredness (daytime sleepiness)
- Observed apnea during sleep
- Pressure (hypertension treatment)
- BMI > 35 kg/m²
- Age > 50 years
- Neck circumference > 40 cm (16 in for women, 17 in / 43 cm for men)
- Gender (male)
A score of 5 to 8 indicates high risk for moderate-to-severe OSA, alerting the perioperative team to prepare difficult airway equipment, plan regional anesthesia techniques when feasible, minimize systemic opioids, and order post-anesthetic continuous pulse oximetry.
Exam Traps & Clinical Pitfalls
- Exam Trap: Confusing ASA III and ASA IV definitions. Remember that ASA IV implies a condition that is a constant threat to life (e.g., MI within the last 30–90 days, severe EF reduction < 30%), whereas ASA III reflects severe systemic disease with functional limitation but not an immediate life threat.
- Clinical Pitfall: Assuming a patient with a normal Mallampati Class I airway cannot be a difficult intubation. Always combine Mallampati with thyromental distance (< 6 cm) and cervical mobility assessments.
A 58-year-old male is scheduled for an elective laparoscopic cholecystectomy. His medical history includes type 2 diabetes mellitus with microvascular complications, morbid obesity with a BMI of 43 kg/m², poorly controlled hypertension, and a history of a drug-eluting coronary stent placed 8 months ago. How should the perioperative nurse classify this patient using the ASA Physical Status Classification System?
During a preoperative physical assessment, a nurse evaluates a patient's functional capacity prior to major abdominal surgery. The patient states they can walk around the house and wash dishes, but become severely short of breath and must stop when trying to walk up a single flight of stairs. How should the nurse interpret this patient's functional capacity in Metabolic Equivalents of Task (METs)?
A perioperative nurse conducts an airway assessment on an adult patient in the preoperative holding area. Upon asking the patient to sit upright, open their mouth wide, and protrude their tongue without phonation, the nurse visualizes only the hard palate; the soft palate, uvula, and faucial pillars are completely obscured. What is the correct Mallampati classification and its primary clinical implication?