Preparation and initiation of anesthesia: 

An ideal anesthetic technique would incorporate optimal patient safety and satisfaction, provide excellent operating conditions for the surgeon, allow rapid recovery, and avoid postoperative side effects. In addition, the chosen technique would be low in cost, allow early transfer or discharge from the post anesthesia care unit, optimize postoperative pain control, and permit optimal operating room efficiency, including turnover times. The anesthesia provider must evaluate the medical condition and unique needs of each patient, select an acceptable anesthetic technique, and make this recommendation to the patient.

Preparation for anesthesia

2.1.2: Initiation of anesthesia (Induction):

General anesthesia may be initiated by the administration of Parenteral drugs or inhalation of a volatile anesthetic (Table 2:1). General anesthesia renders a patient insensible to pain (analgesia); make the patient unaware of the procedure (amnesia); and muscle relaxation for surgical purposes. Vigilance, to be alert to danger or threats, is essential during the administration of general anesthesia. During general anesthesia the patient is reliant upon the anesthetist to maintain a patent airway, provide adequate oxygenation, and support of adequate heart function and other vital organ function.

Table 2: 1 General anaesthetic techniques
Type Techniques
Mask anaesthesia 
(including laryngeal mask)
  • Induction inhalational, intravenous or intramuscular.
  • Maintenance of anesthesia during surgery with the patient breathing spontaneously using an air/O2/inhalational agent
Endotracheal anesthesia
  • Induction either intravenous ( e.g. Ketamine 1-2 mg/kg or Thiopentone 3-5 mg/kg I.V.) or inhalational (Halothane)
  • Intubation using an IV muscle relaxant (suxamethenium 1-2 mg/kg I.V) or an inhalational agent, tube position confirmed with chest excretion and auscultation of breath sounds in both lungs
  • Maintenance during surgery either with spontaneous respiration as for mask anaesthesia or intermittent positive pressure ventilation (IPPV) using a long acting muscle relaxant (e.g. Vecuronium .05 - .1 mg/kg I.V) in addition to air/O2/inhalational agent +/– IV analgesia (e.g. Pethedine .5 – 1mg/kg I.V.)
  • Reversal of the muscle relaxation at the end of surgery (Neostigmine + Atropine)
 Total intravenous anesthesia  It is a technique of general anesthesia using combination of agents given solely by the intravenous route and in the absence of inhalational agents.
 Monitored anesthesia care (MAC) or Conscious sedation
  •  It refers to the anesthesia personnel present during a procedure and does not implicitly indicate the level of anesthesia needed. Administration of sedatives, analgesics, hypnotics, anesthetic agents or other medications as necessary to ensure patient safety and comfort
  • MAC is a specific anaesthetic service for diagnostic or therapeutic procedures.
  • Indications for monitored anesthesia care include the nature of the procedure, the patient's clinical condition and/or the potential need to convert to a general or regional anaesthetic.
  • MAC may include varying levels of sedation, analgesia, and anxiolysis as necessary. Monitoring of vital signs, maintenance of the patient's airway and continual evaluation of vital functions.
  • The provider of MAC must be prepared and qualified to convert to general anesthesia when necessary.
 Balanced anesthesia
  •  The concept emphasized the use of multiple drugs to produce unconsciousness and analgesia, provide skeletal muscle relaxation, and prevention of reflex responses.
  • No single anesthetic drug could provide all the characteristics of an ideal general anesthesia, but a combination of intravenous analgesics (e.g., pethedine), neuromuscular blocking drugs (e.g., pancuronium), and hypnotics (thiopentone) given together produced the desired balanced anesthetic.
  • Lower doses of each drug could be used because the different drugs tended to act synergistically.

Intravenous induction of general anesthesia
the administration of anesthetic drugs (propofol, thiopental, or ketamine) to produce rapid onset of unconsciousness it is usually used in adult patients by the intravenous administration of an anesthetic that produces. Then, ventilation can be sustained via a face mask or a laryngeal mask air-way (LMA) may be inserted or a neuromuscular blocking drug may be given intravenously to facilitate direct laryngoscopy before tracheal intubation.
Intramuscular induction: 

Anesthetic drugs can be administered intramuscularly. Uncooperative children are often anesthetized with drug given by this route. The drug that is given most often by intramuscular route is ketamine (5 to 10mg/kg, induction occurs within a few minutes (3 to 4 minute), followed by 10–15 minutes of surgical anesthesia.

Inhalation induction

The administration of volatile anesthetics (e.g., halothane) through a mask to induce general anesthesia. Often used in the pediatric population. After an inhaled induction of anesthesia, a depolarizing (suxamethonium 1-2 mg/kg) or nondepolarizing neuromuscular blocking drug (Vecuronium 0.08- 0.1 mg/kg) is administered intravenously to provide the skeletal muscle relaxation needed to facilitate direct laryngoscopy for tracheal intubation. If endotracheal intubation is not accomplished, anesthesia can be maintained by inhalation via a facemask or laryngeal mask airway (LMA)