Introduction to anaesthesia

Terms Anaesthesia Anesthesiologist Anesthetist

modern general anesthesia is based on the ability to provide adequate analgesia and amnesia during surgical procedures. Muscle relaxant may be used to facilitate surgical exposure Normal physiological function

The challenge in anaesthesia is: To maintain a balance between the stress of the surgical procedure and the cardio- respiratory depressant effects of deepening levels of anaesthesia

Anaesthesia Surgery Physiological stability End organ homeostasis -Cardiovascular -respiratory -neural -renal -endocrine Stress -psychological -physiological -blood loss -fluid shift -cardiovascular stress -respiratory stress -temperature changes -organ insult

The anesthetic surgical balance Surgical insult Physiological stress Amnesia Analgesia Muscle relaxant

General anaesthesia A state of general anaesthesia may be induced with the injection of anaesthetic drugs, or by the inhalation of a mixture of anaesthetic vapour With general anaesthesia, muscle relaxants may be used to facilitate both tracheal intubation and muscle relaxation

As muscle relaxants have no effect on the state of consciousness, additional anaesthetic medications must be given to ensure both amnesia and analgesia. The use of muscle relaxants avoids the need for excessive amounts of other anaesthetic agents that would otherwise be required to achieve the same degree of muscle relaxation

When muscle relaxant use positive pressure ventilation is frequently use When muscle relaxants are not use the patient may be allowed to spontaneously inhale anaesthetic vapors to maintain the anesthetic state

Anaesthetic Options -eg. iv Propofol, midazolam, fentanyl -e.g. droperidol + opioid (such as fentanyl) -e.g. Spinal Anaesthesia Epidural Anaesthesia Brachial Plexus Block Intravenous 'Bier' Block Peripheral Nerve Blocks 1-Local Anaesthesia alone 2-Local Anaesthesia with intravenous conscious sedation 3-Neurolept-analgesia 4-Regional Anaesthesia, with or without sedation

Anaesthetic Options 5-General Anaesthesia 6-others May be combined with regional anaesthesia, peripheral nerve blocks or local anaesthesia -Acupuncture Inhalational agents im, po, iv sedatives, narcotics, neuroleptics, or antiemetics

Modem general anaesthesia uses combinations of medications in an attempt to minimize each drug's side effects, and maximize individual benefits.