Describe Conduct of General Anaesthesia in detail.

Overview

The conduct of a general anaesthetic is conventionally divided into three phases — induction, maintenance and emergence (recovery) — preceded by preoperative assessment and preparation and followed by postoperative recovery-room care. Safe practice depends on checking the machine and equipment, monitoring, and preparing drugs before starting.

Induction

Induction is the transition from the awake to the anaesthetised state. It is usually achieved intravenously (e.g. propofol) for a rapid, smooth onset, or by inhalation (a volatile agent, e.g. Sevoflurane) — useful in children or where maintaining spontaneous ventilation/airway is important. After loss of consciousness the airway is secured (face mask, supraglottic airway or tracheal tube, often facilitated by a muscle relaxant). Preoxygenation before induction builds an oxygen reserve.

Maintenance

Maintenance keeps the patient anaesthetised for the duration of surgery, delivering the components of the triad: hypnosis (a volatile agent, or a continuous propofol infusion in total intravenous anaesthesia, TIVA), analgesia (opioids, regional blocks), and muscle relaxation where needed, with ventilation controlled or spontaneous. Depth and physiology are continuously monitored and adjusted.

Emergence & Recovery

Emergence is the return to consciousness as the anaesthetic agents are discontinued and eliminated. Muscle relaxation is reversed (or allowed to wear off) and confirmed, the patient is extubated when protective reflexes and adequate breathing return, and they are transferred to the recovery room (PACU) for monitored recovery. Analgesia, anti-emesis, oxygen and observation continue until the patient is stable.

Postoperative Care

In the recovery room the patient is monitored for airway patency, breathing, circulation, consciousness, pain and nausea until they meet discharge criteria. Adequate analgesia, anti-emetic cover, and oxygen therapy are provided, and any complications (hypoxia, hypotension, bleeding, delayed awakening) are managed before the patient returns to the ward.

Preparation Before Induction

Safe anaesthesia begins before the patient is touched. The anaesthetist confirms the machine check is complete, prepares and clearly labels the drugs (induction agent, relaxant, emergency drugs), lays out and checks the airway equipment (laryngoscope, correct-size tubes and supraglottic airways, bougie), ensures working suction, applies full monitoring, and secures reliable intravenous access. A pre-induction ‘sign-in’ and team briefing confirm the patient’s identity, consent, allergies, fasting status and any anticipated airway or other difficulty, so that the plan — and a plan for failure — is shared before starting.

Airway Choice for Maintenance

A key decision during induction is how the airway will be managed for the case: a face mask for very brief procedures, a supraglottic airway (LMA) for suitable spontaneously-breathing patients at low aspiration risk, or a tracheal tube where the airway must be protected (aspiration risk, shared airway, prolonged or major surgery, or when muscle relaxation and controlled ventilation are needed). The choice shapes whether a muscle relaxant is given and whether ventilation is spontaneous or controlled during maintenance.

Induction and emergence are the periods of greatest risk.

• Three phases: induction, maintenance, emergence — plus pre-op preparation & recovery.
• Induction: IV (propofol) or inhalational; preoxygenate; secure the airway.
• Maintenance: volatile agent or TIVA + analgesia + relaxation; continuous monitoring.
• Emergence: stop agents, reverse relaxant, extubate awake with reflexes; recover in PACU.
• Induction & extubation are the highest-risk periods — prepare fully.