Surgery Shelf Exam Review Lecture

Overview

• Lecture created for personal study for Step 2, focusing on surgery-related medicine concepts.
• Emphasis on medicine concepts in surgical patients, rather than extensive surgical details.
• Interactive PowerPoint with questions to assess knowledge and study needs.
• Audio and video will be available for review; slides shared the following day.

Preoperative Evaluation

• Absolute Contraindications to Surgery:
  • Diabetic coma, DKA
  • Sky-high glucose levels due to infection risk.
• Nutritional Status Indicators:
  • Albumin < 3
  • Transferrin < 200
  • Weight loss > 20%
  • Enteral feedings preferred over TPN.
• Liver Function Indicators:
  • Bilirubin, PT, ammonia levels, signs of encephalopathy.
• Smoking:
  • Advise quitting 2 months before surgery.
  • Keep SATs below 100% in smokers to avoid respiratory drive suppression.

Preoperative Risk Factors

• Goldman's Index:
  • Assesses operative risk.
  • Congestive Heart Failure (CHF) is the most important factor.
  • Ejection Fraction < 35% contraindicates surgery.
  • Recent MI within 6 months increases mortality risk.
• Preoperative Testing:
  • EKG for all patients over 50.
  • Abnormal EKG may lead to stress tests, cath lab.

Ventilator Settings

• Assist Control:
  • Preset tidal volume and minimum rate.
• Pressure Support:
  • Provides assistance to patient's own breaths.
• CPAP:
  • Continuous positive pressure for alveoli opening.
• PEEP:
  • Used in ARDS to keep alveoli open.
• Regular ABG tests to adjust settings based on PaO2 and PaCO2 levels.

Acid-Base Disorders

• Acidosis: Determine type by bicarb and PaCO2.
  • Metabolic Acidosis: Check anion gap (normal 8-12).
  • Anion Gap Causes: MUDPILES.
• Alkalosis: Check bicarb and PaCO2.
  • Determine based on urine chloride.

Electrolytes

• Hyponatremia:
  • Caused by excess water not low sodium.
  • Check volume status and treat based on severity.
• Hypernatremia:
  • Replace water; avoid cerebral edema with slow correction.

Burns

• First-Degree: Epidermis only.
• Second-Degree: Partial thickness, painful.
• Third-Degree: Full thickness, no sensation.
• Complications:
  • Compartment syndrome in circumferential burns.
  • Laryngoedema risk with inhalational injury.
  • Carbon monoxide poisoning treatment: 100% O2.

Clotting and Bleeding Disorders

• Hypercoagulable States:
  • Cancer, nephrotic syndrome, factor V Leiden.
  • HIT (Heparin-Induced Thrombocytopenia): Treat with synthetic heparins.
• Bleeding Disorders:
  • ITP, von Willebrand's, DIC (disseminated intravascular coagulation).

Trauma and Surgical Emergencies

• Airway Management: Intubate in cases of unconsciousness, GCS < 8, etc.
• Chest Trauma: Recognize and treat pneumothorax, hemothorax, contusions.
• Abdominal Trauma: Immediate surgery for gunshot wounds, penetrating trauma with instability.

Postoperative Complications

• Fever Causes:
  • Atelectasis, pneumonia, UTI, wound infection.
  • Malignant hyperthermia: Treat with dantrolene.
• Shock Types:
  • Differentiate based on CVP, neck veins, response to fluids.

Miscellaneous Surgical Conditions

• Burn Fluid Resuscitation: Parkland formula.
• ARDS Diagnosis and Treatment:
  • Bilateral infiltrates, low PaO2/FiO2 ratio, low wedge pressure.
  • Use PEEP.
• Lung Cancer Types:
  • Adeno, squamous, small cell, and large cell differentiation.

Gastrointestinal Topics

• Esophageal Disorders:
  • Achalasia, GERD, Boerhaave's syndrome.
• Peptic Ulcer Disease:
  • Gastric vs. duodenal ulcers.
• Pancreatitis:
  • Diagnose with CT, supportively treat.
• Gallbladder Pathologies:
  • Cholecystitis vs. choledocholithiasis.

Conclusion

• Comprehensive review covered, slides to be shared for further study.