conduction of general anesthesia

Dr. Wesam Farid MousaAss. Prof. Consultant of Anesthesia and ICU

Dammam University

Overview• What is general anesthesia?• Preoperative preparation• Induction: Deparutre• Maintenance: Flying• Emergence: Landing • Transport

What is general anesthesia• Primary goals

Amnesia Hypnosis Analgesia

Immobolity

• Secondary goals Medical condition Surgical procedures Surgical settings

Examples for secondary goals • Patients with CAD: Oxygen supply-

demand balance • Neurosugery: ICP control, brain

relaxation and CPP maintenance• Obstetrics: anesthetics and fetal

depression, difficult airway• Day surgery vs Inpatient: which kind of

analgesic you should choose to minimize postoperative pain and decrease PONV?

Preoperative preparation• Preoperative evaluations for: Airway examination Pt’s medical condition Medications Laboratory data Consultant notes Last oral intake

• Preoperative hydration and correction of intravascular volume as needed:Intravenous accessFluid or blood transfusion as needed

• Prescribe preoperative medications as needed:

e.g. Anxiety: Benzodiazepine: Midazolam Pain: Opioid or NSAI

Increased gastric acidity: cimetidine, omeprazole

Monitoring

Standard monitoring for GA

Qualified anesthetist presence

ECG

NBP

Pulse oximetry

Capnography

Teperature (American)

Oxygen analyzer (Canadian)

InductionLet the pt go off to sleep

Preoxygenation

8L~10L/min

IV or Inhalational

induction

Airway management

Induction techniques• Intravenous: the most common method

• Inhalation: for special pt (as pt with difficult airway, pediatric pt)

• Intramuscular :rarely used, only used in uncooperative pts and young children

MaintenanceIncreasing depth of anesthesia

stageⅠ

Amnesia

Loss of

consciousness

Stage ⅡDelirium

Injurious responses

to noxious stimuli

Stage Ⅲ

Surgical anesthesia

Painful stimulation does

not elicit somatic reflexes

or deleterious autonomic

responses

Stage Ⅳ

Overdosage

Circulatory

failure

Maintenance Anethesia • Volatile

• Nitrous oxide-opioid relaxant technique

• IV anesthesia

• Combinations

•Maintain homeotasisVital signsAcid-base balanceTemperatureCoagulationVolume status

Maintain Ventilation1. Spontaneous or assisted

ventilation

2. Controlled ventilation Tidal volume: 10-12ml/kg Respiratory rate: 8-10 breaths/min

Maintain Intravascular Volume

1. fluidsCrystalloid sollutions:Colloid sollutions:

2. Blood & blood products

Emergence from GA

Extubation• Awake extubationIndications Risk of aspiration Difficult airways Tracheal or maxillofacial surgery

• Awake extubation Criteria Awake Hemodynamically stable Full muscle strength Able to follow simple verbal

commands Breathing spontaneously with

adequate ventilation

• Deep extubationIndications Severely asthmatic patients Middle-ear surgery Open-eye surgery Inguinal herniorrhaphy

• Deep extubationCriteria Sufficient anaesthetic depth to

avoid response to airway stimulation

Spontaneous breathing with adequate ventilation

Goals to be met before discharge from recovery:

awake Responsive Full muscle strength Adequate pain control

TransportIt is the responsibility of the

Anaesthetist

Questions