General Anesthesia (GA)
What’s general anesthesia? How to anesthetize the patient?
Four clinical end points of GA
Classification of General Anesthesia Inhalational GA Intravenous GA Combined GA
Procedure of GA Induction from awake to sleep (hypnotic) and ready for surgery preoxygenation induction with intravenous or inhalational anesthetics Tracheal intubation , mechanical ventilation Maintenance four endpoints Emergence Awake, spontaneous respiration no residual muscle relaxation
Tracheal intubation Open and seal the air way ventilation Deliver inhalational anesthetics stiletto
Tracheal intubation
Special Apparatus McCoy Mccoy Polio Polio Soper Soper Hinged blade tip
Supraglottic Devices Laryngeal Mask Airway Combitube
Difficult airway Apparatus Tracheotomy
Verify Position chest expansion bilaterally listening over the epigastrium and the lung fields Continuous waveform capnography exhaled CO2 ,esophageal detector device (EDD) If in doubt, laryngoscope to visualize the tube passing through the vocal cords If still in doubt, bag-mask ventilation chest x-ray (when feasible) above the carina
Anesthetic Machine Composition of AM Gas supplies Vaporizer ventilator Breath circle
Maintenance and Monitoring
Depth of Hypnotic effect
Neuromuscular Function TOF
Autonomic stability evaluation ECG SPO2 BP CVP T
Autonomic stability evaluation PETCO2 Sevoflurane BIS BIS
What about analgesia ? MAC Spinal reflex Intravenous GA analgesic
Emergence Conscious No residual relaxation Spontaneous respiration Head rise 5 s , tongue protrude VT > 500ml SpO2 >95% (inspiration air) No residual relaxation TOF ratio > 90% Analgesia PCA
for management of anesthetized patient Special techniques for management of anesthetized patient
Deliberade Hypotension Methods Inhalational anesthetics isoflurane Vasodilator Nitroprusside sodium Nitroglycerine Autonomic ganglia blocker Objectives facilitate surgery decrease blood loss Safety stand ≥70 % of Basic lever SAP ≥ 80mmHg MAP ≥ 60~70mmHg Time limit 30~90 min
Hypothermia Objectives Grades Methods Decrease MR Maintain Basic metabolic requirement of Cell Grades Low hypothermia 35 ℃ ~ 32 ℃ Middle hypothermia 31 ℃ ~ 26 ℃ Deep hypothermia <25 ℃ Methods Extracorporeal Cardiopulmonary Bypass
Cardiopulmonary Bypass Basic parts of the Set Preload and hemodilution HCT 20%~25% Hb 70 ~ 80 g/L Heparin 300~400 U / kg ACT>480~ 600s Pup flow 2.2~2.8L/(m2.min) 100~150 ml/kg (child) Myocardial protection K+ 20mmol/L
Autologous transfusion Preoperational hemodilution ANH 10~15ml/kg Blood Salvages anticoagulation Prof. Wang Xue-ren xrwang@mail.hust.edu.cn
The best safety lies in f e a r