Preoperative Medical History & Physical Exam — Anesthesia Lecture

Preoperative Medical History & Physical Examination
Your Blueprint for Safe Anesthesia

Part 1: The Preoperative Medical History – Anticipating Perioperative Risks

1.1 Chief Complaint & History of Present Illness (HPI)

Start with the surgical indication: “Why are you having surgery?” Then use the OPQRST framework—but tailor it to anesthesia-specific concerns. Focus on symptom triggers, duration, severity, and associations that may signal hidden risk.

• Key anesthesia-relevant clues:
  • Exertional dyspnea → possible heart failure
  • Chest pain worsening with position → aortic dissection risk
  • Recent fevers or jaundice (e.g., for cholecystectomy) → may affect NPO status or antibiotic planning
• Red flag: Any recent infection or clinical decompensation may warrant delaying elective surgery.

💡 Pro Tip: Always screen for acute illness—postponing surgery for a URI in a child or uncontrolled CHF in an adult can prevent life-threatening complications.

1.2 Past Medical, Surgical & Anesthesia History

Identify comorbidities using the Revised Cardiac Risk Index (RCRI) as a mental checklist:

• Ischemic heart disease
• Heart failure
• Cerebrovascular disease
• Insulin-dependent diabetes
• Creatinine >2 mg/dL
• High-risk surgery (e.g., aortic, major vascular)

System-Specific Focus:

• Cardiovascular: MI <6 months? Arrhythmias? Valvular pathology?
• Pulmonary: COPD severity, OSA (use STOP-BANG), recent asthma exacerbations
• Neurologic: Stroke history, seizure disorders (watch for anesthetic interactions)
• Renal/Hepatic: Impacts drug metabolism and dosing
• Obesity: Increases risk of difficult airway, positioning injuries, and hypoventilation

Anesthesia History:

Ask directly:
“Did you have any breathing problems during past surgeries?”
“Any severe nausea or muscle stiffness afterward?”

• Critical red flags:
  • Personal/family history of malignant hyperthermia (MH)
  • Pseudocholinesterase deficiency (prolonged apnea after succinylcholine)

🚨 Pitfall Alert: A patient may say “my heart is fine,” but a silent ejection fraction of 25% tells a different story.

1.3 Medications, Allergies & Herbal Supplements

Category	Anesthesia Concerns	Action
Anticoagulants	Bleeding risk with neuraxial anesthesia	Hold warfarin 5 days preop; consider bridging
Beta-blockers	Rebound tachycardia/hypertension if stopped	Continue through morning of surgery
Antihypertensives	Risk of intraoperative hypotension	Hold morning dose if BP is well-controlled
Allergies	True IgE-mediated reactions (e.g., to latex, NMBAs)	Document reaction type: rash ≠ anaphylaxis
Herbals	Ginkgo (bleeding), St. John’s Wort (CYP450 induction)	Discontinue 1–2 weeks preop

💡 Compliance Check: Polypharmacy in elderly patients increases delirium risk—ask how they take meds, not just what they take.

1.4 Family & Social History

• Family:
  • MH susceptibility (RYR1 mutations)
  • Bleeding disorders (e.g., von Willebrand disease)
• Social:
  • Tobacco: >40 pack-years → poor wound healing, airway reactivity
  • Alcohol: >3 drinks/day → withdrawal risk (CIWA protocol may be needed)
  • Illicit drugs: Cocaine → coronary vasospasm; opioids → tolerance
• Functional Status:
  • METs assessment: “Can you walk up 2 flights of stairs?”
  • <4 METs = high cardiac risk

🌟 Example: A 58-year-old male smoker on CPAP for OSA → plan for postoperative CPAP and avoid sedatives.

1.5 Review of Systems (ROS) – Targeted & Efficient

Focus on 8 key systems; positives trigger deeper evaluation:

• Cardiovascular: Chest pain, orthopnea, PND
• Respiratory: Snoring, witnessed apneas, chronic cough
• GI/GU: GERD (aspiration risk), urinary retention (opioid caution)
• Neuro/Psych: Dizziness, baseline cognition (delirium risk)
• Endocrine: Uncontrolled DM → infection, delayed healing

🔍 STOP-BANG ≥3? → High risk for difficult mask ventilation and postoperative respiratory depression.

Documentation Must-Haves:

• Summary of key risks
• ASA Physical Status
• Clear recommendation: “Proceed with regional anesthesia” or “Delay for cardiology clearance”

Part 2: The Preoperative Physical Examination – Focused & Functional

⚠️ Rule: If exam is >30 days old, repeat it before induction (per ASA).

2.1 Vital Signs & General Survey

• Essential vitals:
  • BP (check both arms—difference >20 mmHg suggests aortic dissection)
  • HR (irregular? tachycardic?)
  • SpO₂ (room air)
  • Temp (fever = possible infection)
  • BMI (for drug dosing & positioning)
• General appearance:
  • Alert vs. lethargic
  • Cachexia, edema, signs of frailty

🎯 Example: BP 190/105 + HR 110 → optimize antihypertensives; elective case may be postponed.

2.2 Airway Assessment – Your #1 Priority

Use the LEMON Rule:

Component	Technique	Red Flags
L – Look externally	Facial symmetry, neck scars, micrognathia	Short neck, radiation fibrosis
E – Evaluate 3-3-2	Interincisor gap ≥3 fingers; mentum-hyoid ≥3; hyoid-thyroid ≥2	<3 cm → difficult laryngoscopy
M – Mallampati	Class I (uvula visible) → Class IV (only hard palate)	Class III/IV = high risk
O – Obstruction	Stridor, hoarseness, tumors	Supraglottic pathology
N – Neck mobility	Extension >80°? Flexion intact?	C-spine fusion → limited view

🔥 Critical Insight:
– Difficult mask ventilation predictors: beard, obesity, edentulous, age >55
– Never rely on one test—combine LEMON, thyromental distance (>6 cm ideal), and jaw thrust test for 80–90% sensitivity

🛑 High-Risk Plan: If multiple red flags → awake fiberoptic intubation or video laryngoscope standby

2.3 Cardiovascular Examination

Per ACC/AHA, rule out active cardiac conditions:

• Unstable angina
• Decompensated heart failure
• Significant arrhythmias

Exam Focus:

• JVP: >5 cm H₂O → right heart failure
• Palpation: Heaves (LVH), thrills (severe AS)
• Auscultation:
  • Aortic stenosis murmur (harsh, radiates to carotids) → high perioperative mortality
  • S3 gallop → systolic dysfunction
• Pulses: Diminished femorals → PAD; carotid bruits → stroke risk

🩺 Example: New systolic murmur + dyspnea → urgent echo before non-emergent surgery.

2.4 Respiratory Examination

• Inspection: Use of accessory muscles, barrel chest (COPD)
• Auscultation:
  • Wheezes → bronchospasm → give albuterol pre-induction
  • Crackles → pulmonary edema or pneumonia
• SpO₂ <92% on room air → investigate cause before proceeding

💨 OSA Alert: Even if asymptomatic, STOP-BANG+ patients need enhanced post-op monitoring.

2.5 Other Systems (As Indicated)

• Neurologic: Baseline mental status (for delirium tracking), focal deficits
• Abdomen: Distension → possible bowel obstruction (delays surgery)
• Skin/Extremities: IV access quality, signs of DVT (unilateral swelling, Homan’s sign)

ASA Physical Status (PS) Classification – Communicate Risk Clearly

Class	Description	Example
I	Healthy	25yo athlete, inguinal hernia
II	Mild systemic disease	Controlled HTN, laparoscopic cholecystectomy
III	Severe disease, not incapacitating	Stable angina, T2DM, hip arthroplasty
IV	Severe, constant threat to life	Recent MI, emergent bowel resection
V	Moribund, not expected to survive 24h	Ruptured AAA
VI	Brain-dead organ donor	—
E	Emergency (add “E” to any class)	Trauma laparotomy (Class II → II-E)

📊 Why It Matters: ASA PS strongly correlates with morbidity and mortality—higher classes need multidisciplinary optimization.

Part 3: Integration, Testing & Anesthetic Planning

Synthesize Findings into Action

• Airway Class III + OSA → Avoid deep sedation; have supraglottic airway ready
• RCRI ≥2 + intermediate-risk surgery → Consider non-invasive stress testing
• Uncontrolled DM + infection signs → Delay surgery

Testing Strategy (Per ASA Guidelines)

• ECG: Age >50 or known CV disease
• Labs: Only if history suggests abnormality (e.g., renal disease → creatinine)
• CXR: Not routine—only for acute respiratory symptoms or known lung disease

Build Your Anesthetic Plan

• Regional anesthesia: Ideal for low-risk lower extremity procedures
• General anesthesia:
  • Standard induction if low risk
  • Awake fiberoptic if high airway risk
• Consent: Discuss MH risk, awareness, post-op nausea, and airway complications

🧠 Practice Tip: Review NAP4 (National Audit Project 4) cases—many deaths were preventable with better preop assessment.

Case Challenge: 65-Year-Old Smoker Scheduled for CABG

• Airway focus: Assess for cervical arthritis (limited extension), dentition, neck radiation
• CV focus: Evaluate for aortic stenosis, LV function, recent ischemia
• Plan: Likely GETA with invasive monitoring; ensure beta-blockade continued

🩺 Final Thought:
“The preoperative assessment isn’t paperwork—it’s your first intervention.”
A meticulous history and physical prevent crises before they begin.

Class dismissed! — Prepared for Anesthesia Students | Based on ASA Guidelines & ACC/AHA Recommendations