OPTIMAL BALANCED ANESTHESIA

• Hypnosis -Hypnotics induce sleep
• Anesthesia - Freedom from pain
• Amnesia-No recall of surgery
• Muscle relaxation-Neuro muscular blockers
• Optimal patient positioning
• Ease of physiological monitoring
• Continued homeostasis - anesthesia brings you close to death

GENERAL ANESTHESIA

• Alters patients level of consciousness by:
• Inhalation: Gases=diffusion alveolar membrane=blood stream=CNS...delivered by closed circuit vaporizer
• Injection: Given into blood via IV
• Balanced Anesthesia: Several methods used in combination

STAGES OF GA ACCORDING TO DEPTH

• Stage 1 = Amnesia begins with administration > loss of consciousness >stop breathing
• Stage 2 = Excitement or delirium stage >MAKE SHORT-VERY DANGEROUS!! From loss of consciousness > regular breathing & loss of eyelid reflex     RISKS: Twitching, vomitting, laryngospasm, hypertension, tachycardia - may be decreased by IV induction agents
• Stage 3 = cessation of breathing > ventilator > unresponsive to pain and stimuli, sense of hearing is LAST TO GO
• Stage 4 = As close to death as possible. Dialeted pupils, cessation of respiration - marked hypotension - circulatory failure leads to death

PHASES OF GENERAL ANESTHESIA

• Preinduction
• Induction
• Maintenance
• Emergence
• Recovery

PREINDUCTION

• Begins when patient is admitted to preop, patient assessed and prepared for meds and surgery, transported to OR, monitoring devices placed, ends when induction of anesthesia begins
• One main goal is to have patient calm, physiologically stable and prepared for surgery

INDUCTION PHASE

• Beins when GA is administered and patients airway is secured
• Patient goes to sleep
• Depressed reflexes
• Inadequate airway
• Maintenance of airway is CRITICAL 
• Noise should be minimal
• Patients hearing is last to go - noise should be minimal
• Moving patient suddenly can trigger larynogspasm

INDUCTION WINDOW

• Increased O2 saturation to 100% "hypersaturation" to avoid muscle spasm

FACE MASKS

• May be used for short surgical procedures when muscle relaxation is NOT required
• EX: Myringotomy with placement of PE tubes
• After unconscious, a pharyngeal (oral) airway may be placed in the mouth to hold tongue and facilitate airflow
• Anesthesia supports airway with chin lift position

LARYNGEAL MASKED AIRWAY

(LMA)

• Procedures of short duration
• Positioned in laryngopharynx to cover glottis and epiglottis, LMA cuff inflated to provide seal, tube is connected to breathing circuit
• Does not require laryngoscopy or muscle relaxation
• Useful for ambulatory procedures
• CI = Procedures on oral cavity, obesity, hiatal hernia, GERD, low pulmonary compliance

ENDOTRACHEAL TUBE

• Needed if muscle relaxers are used
• Intubation begins after induction agents are given and patient is unconscious
• Neuromuscular blocker given to relax vocal cords and ET inserted into trachea using laryngoscope which retracts tongue and lifts jaw - may use stylet to guide tube along correct path
• 7.0-8.0 SIZE MOST COMMON

RAPID SEQUENCE INDUCTION

(RSI)

• Used on patients with increased risk of gastric reflux and pulomary aspiration
• Used on patients who have NOT been NPO, esp trauma patients, hiatal hernia, GERD, previous GI surgery, diabetes, obesity
• used to secure and control airway quickly
• Preoxygenation and application of CRICOID pressure

CRICOID PRESSURE

• SELLICK MANEUVER
• Applied to cricoid cartilage, gently compressing esophagus
• Helps prevent gastric contents from entering trachea and lungs
• maintained until ET tube is positioned

NEWBORNS

• DO NOT USE CUFFED ET ON NEWBORNS!!!!!

MC GILL FORCEPS

• Used on fatty, long tongues that need to be manipulated

NASAL INTUBATION

• Surgeries performed on oral cavity ex. mandibular fractures
• Inserted through nose to oropharynx, laryngoscope used to see vocal cords, Mcgill forceps used to guide ET tube into place

CONSCIOUS INTUBATION

• Used is there is potential problem for intubation or ventillation
• Morbid obesity, difficult intubation, facial deformaties, laryngeal cancer or conditions that compromise airway
• Administration of antisialagogue, lidocaine through nebulizer
• Can be done nasal or oral
• Nasal may require vasoconstrictors

DOUBLE LUMEN

• Used for thorax surgery to collapse one lung while other is still working

PULSE OXIMETRY

• Measures amt of hemoglobin in blood
• Determines overall amount of O2 being delivered to tissues
• Measures arterial blood - brighter red, higher the number

CAPNOGRAPHY

• Monitors acidosis
• measures CO2 in expired air - ETC02
• H2CHO3 = Carbonic acid
• Arterial blood 7.41-7.44ph
• Venous blood 7.35ph
• Resp acidosis > Hyperventilate to rid co2 > order ABG > sodium bicarbonate...this will bind and remove excess CO2
• Normal values 35-45mmhg

MAINTENANCE PHASE

• Begins as airway is secured and continues until procedure is completed
• Surgical intervention takes place
• Vital functions maintaned
• Monitors O2 saturation, blood loss, muscle relaxation, cardiac status
• Additional anesthetics given to maintain
• Abdominal and Thoraci require most anesthesia

NEUROLEPTANESTHESIA

• Anesthetic state of sedation and analgesia while allowing patient to breath on their own and move on command
• Also called a dissociative anesthetic
• Droperidol = black-box warning

SEVOFLURANE

• ULTANE - inhalant
• Used for short procedures
• Rapid induction/recovery
• Works well with kids, smooth transition

ISOFLURANE

• FORANE - inhalent
• Longer operations
• Adults
• More potent
• Rapid induction / long recovery

DESFLURANE

• SUPRANE - INHALENT
• Longer operations
• Rapid induction/longer recovery
• Safe in children

HALOTHANE

• FLUOTHANE - inhalent
• LIVER TOXICITY
• CI - CHILDREN

EMERGENCE PHASE

• Begins when surgery is complete and ends when transported to PACU
• Goal is to have patient awake, breathing on their own, return of gag reflex
• Extubation, reversale of muscle relaxers
• Risk of laryngospasm as patient is waking up
• Thermoregulatory changes: rigidity and tremors in late stage
• PATIENT SENSITIVE TO NOISE

RECOVERY PHASE

• Patient regains optimal level of consciousness and wellbeing. Usually begins in OR and continues. Patient then stays in PACU

BERMAN AIRWAYS

• Lifts tongue so air can pass freely

ADVANTAGES OF GA

• Patient unaware of activites during procedure
• Respiration can be controlled
• Medications can be titrated
• Muscle relaxation for intubation and extubation is easily achieved

RISKS AND COMPLICATIONS OF GA

• The preoperative condition of patient is a major factor when determining risk
• ASPIRATION
• LARYNGOSPASM AND BRONCHOSPASM
• MALIGNANT HYPERTHERMIA
• PSEUDOCHOLINESTERASE DEFICIENCY
• ALLERGIC REACTIONS
• SHOCK
• CARDIAC DYSRYTHMIAS
• CARDIA ARREST

ASPIRATION

• May occur when food in stomach
• Neuromuscular blockers can cause vomitting
• Gastric contents can be aspirated and cause chemical pneumonia (aspiration pneumonia)
• Risk is greated during induction and emergence phases
• Cricoid (sellicks) used if needed

LARYNGOSPASM & BRONCHOSPASM

• Occure @ induction and emergence phase
• Slight trigger of gag reflex causes spasm
• May be triggered by saliva, inflamation and lightly sedated patients
• TREATMENT: positive pressure or Succinylcholine

MALIGNANT HYPERTHERMIA

• Potentially fatal hypermetabolic state of muscular activity
• Due to a defect in calcium transportation
• Muscle contract and cant relax - rigidity,heat, buildup of lactic acid
• More common in men
• CAN TRIGGERED BY SUCCINYLCHLOINE
• TREATMENT: Stop anesthesia, 100% 02, DANTROLENE (DANTRIUM) in steril H2O, chilled fluids, normal saline or dextrose in H2O (D5W), chilled lavage of body cavities, pack with ice axillae, groin, base of skull

NAHCO3

• Counteract metabolic and resp acidosis

DEXTROSE & INSULIN

• Cellular metabolism

FUROSEMIDE (LASIX)

• Mannitol
• Promote clearance of waste products

HEPARIN

• Prevent I.V clot formation

PSEUDOCHOLINESTERASE DEFICIENCY

• Genetically transmitted
• ACH causes prolonged muscle contracting
• No treatment
• Resp support until body eliminates block
• PROPHYLAXIS: No depolarizing blockers

ALLERGIC REACTIONS

• Mild skin rash (contact dermatitis)
• Anaphalaxis shock
• Patients history should include previous allergies of meds to avoid

SHOCK

• Sudden adjustment in homeostasis
• Decreased cardiac output
• Hypotension
• Tachycardia
• Decreases urinary output
• Causes tissue damage, blood loss, infection (septic shock)
• Treatment: restore circulatory function and load. Antibiotics for toxic shock, increase COP with blood and IV administration

CARDIAC DYSRYTHMIAS

• Abnormal rate or rythem (ECG)
• Ventricular fibrillation - life threatening
• Treatment: IV Lidocaine hydrochloride, defibrillation, pacemaker

CARDIAC ARREST

• Cessation of hearts function as pump
• Resp and metabolic acidosis
• Initial treatment CPR
• Advanced cardiac life support involves drugs an monitoring