Respiratory Management in Anesthesia

Sep 10, 2024

Lecture on Respiratory Rate and Ventilation

Key Concepts

  • Ventilatory Quality vs. Respiratory Rate
    • Importance of evaluating not just the respiratory rate but the quality of ventilation.
    • Comparison of two patients: rapid shallow respiration vs. slow deep respiration.
    • Dead Space: Fixed anatomical space not contributing to gas exchange.

Understanding Ventilation

  • Minute Ventilation

    • Calculated as the amount of air exchanged in a minute.
    • Rapid shallow vs. slow deep breathing can result in the same minute ventilation.

  • Alveolar Ventilation

    • Amount of air reaching the alveoli and contributing to gas exchange.
    • Example: Deep respiration results in better alveolar ventilation compared to shallow breathing.

Respiratory Assessment

  • Hypoventilation

    • Defined as clinically significant at CO2 levels > 60.
    • End-tidal CO2: Normal ranges are 35-45 in awake patients, higher in anesthetized patients.

  • Causes of Hypoventilation

    • Inhalant-induced CNS depression.
    • Treatment involves adjusting depth of anesthesia and potentially using a ventilator.

Common Issues and Misconceptions

  • Pseudo-Hypoventilation Post-Induction

    • Occurs due to initial bagging and lowering of CO2 levels, leading to delayed spontaneous breathing.

  • Hypoxia During Anesthesia

    • Rare, often due to failed intubation.
    • Importance of confirming intubation to avoid hypoxia.

Practical Tips

  • Intubation

    • Ensure correct placement of the endotracheal tube to prevent hypoxia.
    • Check for leaks and confirm lung sounds.

  • Managing Anesthesia Depth

    • Balance between inhalants, analgesics, and sedatives.

  • Gastroesophageal Reflux

    • Attention to reflux during anesthesia to prevent complications like strictures.

Conclusion

  • Effective management of respiratory and anesthetic parameters is crucial.
  • Understanding the underlying principles helps in dealing with respiratory issues during anesthesia.
  • Practical experience and attention to detail can prevent common problems in respiratory management during surgical procedures.