General Anaesthesia Overview

Study Notes

General Anaesthesia

Definition: A medically induced state of unconsciousness with loss of sensation and reflexes, allowing surgical procedures to be performed without pain.
Indications:
- Major surgical procedures (e.g., abdominal, thoracic, orthopedic surgery)
- Procedures requiring complete muscle relaxation (e.g., intubation)
- Long-duration surgeries
Components:
- Analgesia: Pain relief during and after the procedure.
- Amnesia: Prevention of memory formation during surgery.
- Muscle Relaxation: Facilitates surgical access by relaxing skeletal muscles.
- Unconsciousness: Patient is unaware of the procedure.
Administering Agents:
- Induction Agents: Rapidly induce unconsciousness (e.g., propofol, etomidate).
- Maintenance Agents: Keep the patient unconscious during surgery (e.g., inhalational anesthetics like sevoflurane, desflurane).
- Adjuncts: Additional medications for analgesia (e.g., opioids) and muscle relaxation (e.g., neuromuscular blockers).
Monitoring:
- Vital signs (heart rate, blood pressure, oxygen saturation).
- Depth of anaesthesia (e.g., using bispectral index monitoring).
- Neuromuscular function (if neuromuscular blockers are used).
Risks and Complications:
- Allergic reactions to anesthetics.
- Respiratory complications (e.g., airway obstruction, hypoxemia).
- Cardiovascular issues (e.g., hypotension, arrhythmias).
- Postoperative nausea and vomiting (PONV).
- Delayed recovery from anaesthesia.
Preoperative Assessment:
- Thorough medical history review.
- Evaluation of airway (Mallampati score).
- Risk stratification based on comorbidities (e.g., cardiovascular, respiratory conditions).
Recovery:
- Transitioning from unconsciousness to alertness in the recovery room.
- Monitoring for complications such as respiratory depression or pain management.
- Criteria for discharge from the recovery unit (e.g., stable vital signs, ability to follow commands).
Postoperative Care:
- Pain management strategies.
- Monitoring for potential complications (e.g., infection, thromboembolism).

This summary outlines the key aspects of general anaesthesia, ensuring a comprehensive understanding of its principles, administration, and considerations.

General Anaesthesia

Medically induced state that results in unconsciousness, loss of sensation, and reflex loss, enabling painless surgical procedures.
Commonly indicated for major surgeries (abdominal, thoracic, orthopedic), long duration procedures, and those requiring complete muscle relaxation.

Components of General Anaesthesia

Analgesia: Provides pain relief throughout and following the procedure.
Amnesia: Prevents memory formation during surgery for patient comfort.
Muscle Relaxation: Aids in surgical access by relaxing skeletal muscles.
Unconsciousness: Ensures the patient remains unaware of the procedure.

Administering Agents

Induction Agents: Quickly induce unconsciousness; examples include propofol and etomidate.
Maintenance Agents: Sustain unconsciousness during surgery; inhalational anesthetics like sevoflurane and desflurane are commonly used.
Adjuncts: Additional medications such as opioids for analgesia and neuromuscular blockers for muscle relaxation.

Monitoring

Continuous monitoring of vital signs, including heart rate, blood pressure, and oxygen saturation.
Depth of anaesthesia assessed using tools like bispectral index monitoring.
Neuromuscular function monitored if neuromuscular blockers are part of the regimen.

Risks and Complications

Potential allergic reactions to anesthetics leading to adverse effects.
Respiratory complications, including airway obstruction and hypoxemia.
Cardiovascular risks such as hypotension and arrhythmias.
Postoperative nausea and vomiting (PONV) may occur.
Some patients may experience delayed recovery from anaesthesia.

Preoperative Assessment

Involves a thorough review of the medical history and evaluation of the airway using the Mallampati score.
Conduct risk stratification based on existing comorbidities, particularly cardiovascular and respiratory conditions.

Recovery

Patients transition from unconsciousness to alertness in a recovery room environment.
Monitoring for complications like respiratory depression and managing pain effectively is crucial.
Discharge from recovery is based on stable vital signs and the ability to follow commands.

Postoperative Care

Implementation of pain management strategies to ensure comfort.
Ongoing monitoring for potential complications such as infection and thromboembolism.

Description

Explore the fundamental aspects of general anaesthesia, including its definition, indications, and key components. Understand the various administering agents used for inducing and maintaining unconsciousness during surgical procedures.