1.GENERAL ANESTHESIA
A controllable and reversible loss of consciousness induced by intoxication of the central nervous system. Lowered sensitivity to external stimuli (hyporeflexia), analgesia, unconsciousness, muscle relaxation, and amnesia are significant features of general anesthesia. The term "surgical anesthesia" emphasizes muscle relaxation and analgesia.
Evaluating the p’t before anesthesia
Chart detail
– History
– Anesthesia records
– Family history
– Social history
– Allergy
– Common used medicine
Lab data：CBC, DC, PT, PTT, serum chemistry, Na/K/Cl, urine
ECG, Chest x-ray, lung function
BL, BW, Head Neck, extremity, vital sign, heart beat, breath sound
Interview and informed consent, consultant’s note
2.Adjuncts to Anesthesia
Atropine
anticholinergic drug that blocks the muscarinic receptor sites (mainly organs innervated by the Vagus nerve)
reduction in salivary and other airway secretions
used preoperatively for diminishing secretion
0.4-0.6 mg IM 45-60 prior to anesthesia
Nimbex
Cisatracurium is an intermediate-duration, non-depolarising neuromuscular blocking agent for IV administration
Use for surgical procedures, to relax skeletal muscles, and to facilitate tracheal intubation and mechanical ventilation
IV 0.15 mg/kg initially→ good to conditions for excellent tracheal intubation 120sec following injection
0.3 mg/kg maintain
Reverse→
Succinylcholine
Depolarizing muscle relaxants
– Non-competitive blocker
– Physically resemble Ach
– Can bind to ACh receptors and generate a muscle action potential
– Not metabolized by acetylcholinesterase
Side Effects & Clinical Considerations
– Bradycardia
– Hyperkalemia
– Prolonged paralysis
– Muscle pain
Propofol
Propofol is a diisopropylphenol intravenous rhythmic agent that produces rapid induction of anesthesia with minimal excitatory activity
rapid elimination by the liver
– Conscious sedation
– Induction agent of anesthesia
– Maintenance of anesthesia
– Antiemetic
200mg/20ml/amp
Induction, IV, 1.5-2.5mg/kg;
maintenance, continuous IF, 4-12mg/kg/hr or intermittent IV bolus, 25-50mg
Fentanyl
Morphine 80-100x
IV, 0.05~0.1mg initially followed by 0.025~0.05mg as needed
Respiratory depression, muscle rigidity
fat soluble ☆
Pharmacology of Inhalation Agents
Minimum Alveolar Concentration (MAC)→Alveolar concentration of anesthetic at which 50% of the patients are unresponsive to a standard surgical stimulus
Isoflurane
– MAC 1.15%
– pungency
Sevoflurane
– MAC 1.71%
– Relatively low solubility and non-pungency make it an excellent choice for inhalational induction.
Desflurane
– MAC 5.0~7.25%
– pungent and irritating to the airway
– low solubility
Monitor
Standard monitoring
Temperature、body fluid 〈blood loss、urine〉
ECG、BP、RR、PaO2、PaCO2、FiO2
Special monitoring
Arterial cannulation
– N/S with heparin, 300mmHg
– blood gas analysis, Na+, K+, Hb, Hct
CVP
Hyperthermia
2℃/1hr, 0.5 ℃/15min
– Inflammation
– Hyper metabolic state
– Malignant Hyperthermia
inherited disorder
Triggering Agents
– Depolarizing muscle relaxants
– Volatile general anesthetic agents
Dantrolene
Transfusion
Adult：70ml/kg
Wet gauze－original gauze＋blood loss in suction
blood loss in suction × 1.5
Hb＜10g/dl or Hct＜30
Blood loss＜600 → HARTMANN®
600~1200 → Packed RBC
＞1200 → Whole blood and Packed blood
每單位可使70 kg成人Hb提昇約0.5 g/dL，Hct約1-2 %
PAR score
Morphine
10mg／1ml
1- 3 mg IV prn, Max 50mg／day
used for the relief of moderate to severe pain
respiratory depression
PCA〈patient-controlled analgesia〉
A certain amount of pain medicine is given when the patient pushes the button.
The computer is programmed to give a safe amount of pain medicine over a specific period of time.
A small number of people feel nauseated, have some itchiness, or have difficulty passing urine.
Naloxone
Complete or partial reversal of narcotic depression
Adult:
– Narcotic overdose
SC/IM/IV 0.4-2mg initially, repeat at 2-3 minute intervals up to 10mg, if no response after 10mg reevaluate diagnosis
– Postop narcotic depression (partial reversal)
IV 0.1-0.2mg at 2-3 minute intervals to desired level of reversal; repeat doses may be required within 1-2 hour intervals
Child:
– Narcotic overdose
SC/IM/IV 0.01 mg/kg initially, give subsequent doses of 0.01 mg/kg as needed at 2-3 minute intervals
– Postop narcotic depression
IV 0.005-0.01mg every 2-3 minutes to desired degree of reversal
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