Anesthetic Complications Detailed Notes

Anesthetic Complications

  • Overview of Anesthetic Complications: Complications range from minor issues, such as infiltrated intravenous lines, to catastrophic outcomes, including hypoxic brain injury or death.

Airway Injury

  • Definition: Injury to airway structures during procedures involving endotracheal tubes, laryngeal mask airways, etc.
  • Common Injuries:
    • Sore throat and dysphagia (usually self-limiting).
    • Dental trauma (most common permanent airway injury), often affecting upper incisors during laryngoscopy and endotracheal intubation.
  • Risk Factors for Dental Trauma:
    1. Tracheal intubation.
    2. Poor preexisting dental health.
    3. Patient characteristics: difficulty managing airway due to limited neck motion, previous head/neck surgery, craniofacial abnormalities, or history of difficult intubation.

Peripheral Nerve Injury

  • Definition: Complication from both regional and general anesthesia; more frequent in regional anesthesia.
  • Resolution of Injuries: Most injuries resolve within 6-12 weeks, but some may persist for months or years.
  • Common Types of Nerve Injuries: Related to patient positioning affecting the peroneal nerve, brachial plexus, femoral, and sciatic nerves.
  • Mechanism: External pressure can compromise nerve perfusion, disrupting cellular integrity leading to edema, ischemia, and necrosis.
  • Risk Factors: Hypotension, thin body type, old age, and history of vascular disease, diabetes, or smoking, especially with prolonged lithotomy positioning.

Awareness during Anesthesia

  • Incidence: Awareness under general anesthesia occurs in 0.2-0.4% of cases; most commonly in major trauma, obstetrics, and cardiac surgery.
  • Factors Affecting Awareness:
    • Depth of anesthesia tolerated.
    • Recall rates can reach up to 43% during major trauma surgeries.
    • Specific rates: 1.5% during cardiac surgeries, 0.4% during cesarean sections.
  • Causes: Errors in drug labeling, patient characteristics such as gender, age, medication interactions, and tolerance issues.

Eye Injury

  • Common Eye Injuries: Corneal abrasion is transient; ischemic optic neuropathy (ION) is a significant concern causing postoperative vision loss.
  • Mechanism of ION: Infarction of optic nerve due to decreased blood supply, often post-surgery.
  • Procedures Associated with ION: Reported following cardiopulmonary bypass, radical neck dissections, abdominal and hip procedures, spinal surgeries in the prone position.
  • Contributing Factors: Preexisting vascular conditions (hypertension, diabetes), intraoperative hypotension and anemia can exacerbate the risk.

Preventing Eye Injury

  • Enhance venous outflow (head-up position).
  • Careful monitoring of blood pressure, especially with an arterial line.
  • Limit duration of hypotension during procedures.
  • Administer transfusions for anemic patients at risk.
  • Consider staged operations in high-risk patients to reduce procedure length.

Cardiopulmonary Arrest During Spinal Anesthesia

  • Description: Sudden cardiac arrest related to high-level spinal block (T4 level), although rare, is catastrophic.
  • Treatment Approaches:
    • Ventilatory support.
    • Medications: Ephedrine, atropine.
    • Cardiopulmonary resuscitation (CPR).

Hearing Loss

  • General Observation: Typically transient and unnoticed.
  • Causes of Hearing Loss: Following dural puncture can be due to cerebrospinal fluid leaks; persistence may necessitate an epidural blood patch. Other causes include surgical manipulation, middle ear barotrauma, vascular injury, and ototoxicity of specific drugs.
  • Post-Cardiopulmonary Bypass: Hearing loss is usually unilateral, related to embolism and ischemic injury.

Allergic Reactions

  • Description: Hypersensitivity reactions are exaggerated responses to antigens in previously sensitized individuals.
  • Antigen Sources: Can be proteins, polypeptides, metabolites, or breakdown products, introduced via multiple routes (nose, lungs, skin, gastrointestinal tract, parenteral).

Communication of Anesthesia Risks to Patients

  • Discuss risks and concerns with patients, utilizing available resources for further education (e.g., videos).