General Anesthesia Techniques

Introduction

General anesthesia is a crucial aspect of modern medicine, particularly in surgical procedures. It involves inducing unconsciousness and immobility in patients to prevent pain and discomfort during medical interventions. This guide will explore the fundamental principles, methods, and considerations involved in general anesthesia.

Principles of General Anesthesia

Definition

General anesthesia is defined as a state of controlled unconsciousness characterized by:

1. Loss of consciousness (unresponsiveness)
2. Amnesia (memory loss)
3. Immobility
4. Analgesia (pain relief)

Mechanisms of Action

Anesthetic agents work through various mechanisms:

• Depressant effects on the central nervous system
• Alteration of neurotransmitter function
• Modulation of ion channels and receptors

Stages of Anesthesia

1. Stage 1: Excitement

   • Patient may experience confusion, disorientation, and hallucinations
   • Short-lived and often skipped due to rapid progression

2. Stage 2: Surgical anesthesia

   • Patient becomes unconscious and immobile
   • Last stage before recovery

3. Stage 3: Medullary paralysis

   • Most dangerous stage; patient loses reflexes and vital functions
   • Requires immediate intervention

Types of General Anesthesia

Inhalational Anesthesia

• Uses volatile gases (e.g., sevoflurane, desflurane)
• Can be titrated easily
• Rapid onset and recovery

Example: Sevo-flurane administration markdown

Parameter	Value
Dose	2-3 mg/kg
Rate of injection	50 mg/kg/min
Maintenance	100-150 μg/k/min
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Balanced Anesthesia

• Combination of multiple agents
• Allows for more precise control
• Reduces side effects

Example: Balanced anesthesia combination markdown