Preoperative Medical History and Physical Examination for Anesthesia Students

 # Lecture: Preoperative Medical History and Physical Examination for Anesthesia Students

Good [morning/afternoon], class. Today, we're shifting our focus from general clinical assessment to the specifics of preoperative evaluation in anesthesia. As future anesthesiologists, your preop history and physical aren't just routine—they're your blueprint for safe induction, maintenance, and emergence. A thorough assessment identifies risks like difficult airways, perioperative cardiac events, or adverse reactions to anesthetics, potentially preventing complications that account for up to 50% of postoperative mortality in noncardiac surgery. We'll cover the essentials: history, physical, risk stratification with ASA PS, and integration into your anesthetic plan. Drawing from ASA guidelines and recent updates, let's dive in.

## Part 1: The Preoperative Medical History – Anticipating Perioperative Risks

In anesthesia, the history is directive: prioritize elements that impact airway management, hemodynamic stability, and drug interactions. Aim for a focused interview (10-20 minutes) that informs your anesthetic choice—general vs. regional—and prepares for contingencies. Always review records first, then interview, and document in the preanesthesia record.

### 1.1 Chief Complaint and History of Present Illness (HPI)

Start with the surgical indication: "Why are you having surgery?" Then detail the HPI using OPQRST, but emphasize anesthesia-relevant factors like symptom triggers (e.g., exertional dyspnea suggesting heart failure).

- **Key Focus**: Duration, severity, and associations (e.g., chest pain worsening with position for aortic dissection risk).

- **Example**: For cholecystectomy, note recent fevers or jaundice impacting NPO status or antibiotic needs.

- **Tip**: Screen for recent infections or decompensation that might delay elective cases.

### 1.2 Past Medical History (PMH) and Surgical/Anesthesia History

Uncover comorbidities that elevate perioperative risk. Use the Revised Cardiac Risk Index (RCRI) prompts: ischemic heart disease, heart failure, cerebrovascular disease, diabetes on insulin, creatinine >2 mg/dL, high-risk surgery.

- **Cardiovascular**: Recent MI (<6 months high risk), arrhythmias, valvular disease.

- **Pulmonary**: COPD, OSA (screen with STOP-BANG), asthma exacerbations.

- **Neurologic**: Strokes, seizures (drug interactions with anesthetics).

- **Other**: Renal/hepatic impairment (drug dosing), obesity (airway/positioning risks).

- **Previous Anesthesia**: "Any issues with past surgeries? Breathing tube problems? Nausea after?" Probe for MH family history or pseudocholinesterase deficiency.

- **Example**: "MI 3 months ago, stented; now on dual antiplatelets—discuss continuation."

- **Pitfall**: Assuming stability; verify with recent echoes or stress tests if indicated per ACC/AHA guidelines.

### 1.3 Medications, Allergies, and Herbal Supplements

Reconcile all: prescriptions, OTC, herbals (e.g., ginkgo increases bleeding risk).

| Category | Key Concerns for Anesthesia | Examples/Actions |

|----------|-----------------------------|------------------|

| Anticoagulants | Bleeding with neuraxial blocks | Hold warfarin 5 days preop; bridge if high thrombosis risk |

| Beta-blockers | Continue to avoid rebound HTN | No abrupt stop |

| Antihypertensives | Orthostasis under anesthesia | Hold morning dose if uncontrolled |

| Allergies | Anaphylaxis to agents | True IgE: succinylcholine, latex; note reactions (rash vs. hypotension) |

| Herbals | Interactions (e.g., St. John's Wort induces CYP450) | Discontinue 1-2 weeks preop |

- **Tip**: Quantify compliance; elderly polypharmacy heightens delirium risk.

### 1.4 Family and Social History

- **Family**: MH susceptibility (ryanodine receptor mutations), bleeding disorders.

- **Social**: Tobacco (pack-years; cessation >8 weeks increases risk), alcohol (withdrawal potential), illicit drugs (cocaine cardiotoxicity), occupation (radiation exposure for thyroid surgery).

- **Functional Status**: METs assessment—"Can you climb stairs?" Low (<4 METs) flags CV risk.

- **Example**: "Smoker, 40 pack-years; OSA on CPAP—plan for postop monitoring."

### 1.5 Review of Systems (ROS)

Tailored 8-10 systems; positives drive further eval.

- **CV**: Dyspnea, palpitations, edema.

- **Resp**: Cough, wheeze, snoring.

- **GI/GU**: Reflux (aspiration risk), urinary retention (opioids).

- **Neuro/Psych**: Dizziness, anxiety (sedation needs).

- **Endocrine**: Uncontrolled DM (infection risk).

- **Tip**: Positive OSA? Use STOP-BANG (Snoring, Tiredness, Observed apnea, Pressure, BMI>35, Age>50, Neck>40cm, Gender male)—score ≥3 predicts difficult mask ventilation.

**Documentation**: Summarize risks, assign ASA PS (see below), and note plan (e.g., "Elective; proceed with regional").

## Part 2: The Preoperative Physical Examination – Focused and Functional

The exam is directed: airway first, then systems impacting anesthesia stability. Use IPPA, but prioritize prediction over comprehensiveness. Perform immediately pre-induction if >30 days old, per ASA. Baseline vitals are mandatory.

### 2.1 Vital Signs and General Survey

- **Vitals**: BP (both arms; >180/110 delays elective), HR (arrhythmias?), RR, SpO2, temp. BMI for dosing.

- **Survey**: Alertness, hydration, frailty (e.g., cachexia signals poor reserve).

- **Example**: HTN + tachycardia = beta-blocker optimization.

### 2.2 Airway Assessment – Your Non-Negotiable Priority

Failure to assess airway is the top cause of adverse events. Use LEMON (Look, Evaluate 3-3-2, Mallampati, Obstruction, Neck mobility) or similar.

| Component | Technique | Red Flags |

|-----------|-----------|-----------|

| Look Externally | Inspect face/neck for masses, scars, burns | Trauma, tumors, short neck (<3 fingerbreadths) |

| Evaluate 3-3-2 Rule | 3 fingers mouth opening, 3 mentum-hyoid, 2 hyoid-thyroid | <3cm interincisor gap predicts Cormack-Lehane ≥3 |

| Mallampati | Class I-IV (tongue protrusion) | III/IV: limited view |

| Obstruction/Neck | Thyromental distance (>6cm), ROM (>80° extension) | Limited flexion/extension (c-spine disease) |

| Advanced (if suspected) | Nasoendoscopy for supraglottic view | Stridor, hoarseness |

- **Tip**: Predict difficult ventilation (beard, obesity) and intubation. High-risk? Plan awake fiberoptic.

- **Pitfall**: Over-reliance on one test; combine for 80-90% sensitivity.

### 2.3 Cardiovascular Examination

Per ACC/AHA, assess for active disease (unstable angina, decompensated HF).

- **Inspection/Palpation**: JVP (>5cm HF), heaves (LVH), edema.

- **Auscultation**: Murmurs (aortic stenosis high-risk; grade, radiation), S3/S4 gallops.

- **Pulses**: Carotids (bruits), peripherals (claudication).

- **Example**: New murmur + dyspnea = echo preop.

- **Tip**: Functional capacity via exam (e.g., orthostasis test).

### 2.4 Respiratory Examination

- **Inspection**: Chest symmetry, accessory muscle use.

- **Palpation/Percussion**: Fremitus, dullness (effusion).

- **Auscultation**: Wheezes (asthma), crackles (HF/pneumonia).

- **Example**: Reduced SpO2 + wheezes = bronchodilators pre-induction.

### 2.5 Other Systems (As Indicated)

- **Neuro**: Focal deficits (stroke risk), baseline cognition (delirium screen).

- **Abdomen**: Distension (bowel obstruction delays).

- **Skin/Extremities**: IV access sites, DVT signs.

**ASA Physical Status (PS) Classification**: Assign based on exam/history to communicate risk.

| ASA Class | Description | Example |

|-----------|-------------|---------|

| I | Healthy | Young adult for hernia repair |

| II | Mild systemic disease | Controlled HTN for cholecystectomy |

| III | Severe disease, not incapacitating | Stable angina for hip replacement |

| IV | Severe, constant threat to life | Recent MI for emergent appendectomy |

| V | Moribund, not expected to survive | Ruptured AAA |

| VI | Brain-dead organ donor | N/A |

| E | Emergency (+ to any class) | Trauma |

- **Tip**: PS predicts outcomes; higher classes warrant multidisciplinary consults.

## Part 3: Integration, Testing, and Plan

Correlate findings: Airway III + OSA = supraglottic first. RCRI ≥2 + intermediate surgery = consider stress test. Labs/ECG guided by history (e.g., ECG for age >50 or CV disease).

- **Anesthetic Plan**: Regional for low-risk legs; GETA with fiberoptic for airways.

- **Consent**: Discuss risks (e.g., awareness, MH).

- **Practice**: Simulate with actors; review NAP4 cases for pitfalls.

Questions? Let's case-discuss: 65yo smoker for CABG—what's your airway/CV focus? Keep assessing—lives depend on it. Class dismissed!