Anesthesia The word anesthesia comes from a Greek word meaning absence or loss of sensation. The goals of anesthesia include the following:  Anesthesia  Akinesia  Muscle relaxation  Autonomic control There are three main types of anesthesia:  General anesthesia  Regional anesthesia  Local anesthesia

The anesthetic plan Premedication Premedication Type of anesthesia Type of anesthesia General General Airway management Airway management Induction Induction Maintenance Maintenance Muscle relaxation Muscle relaxation Recovery Recovery Local or regional anesthesia Local or regional anesthesia Technique Technique Agent Agent Monitored anesthetic care Monitored anesthetic care Supplemental oxygen Supplemental oxygen Sedation Sedation Intraoperative management Intraoperative management Monitoring Monitoring Positioning Positioning Fluid management Fluid management post operative management post operative management Pain control Pain control Intensive care Intensive care postoperative ventilation postoperative ventilation HEMODYNAMIC MONITORING HEMODYNAMIC MONITORING

Preoperative preparation The preoperative preparation & assessment is a vital part of the anesthetic care given to patients scheduled for both routine & emergency surgery. All patients should be seen & assessed by anesthetist who is responsible for the administration of their anesthetic. AAAAvoid the chance of mistakes during hand over. EEEEnsures continuity & rapport for both the anesthetist & the patient. PPPPoor preparation may begin a series of problems & misadventures. Preoperative visits The purposes of preopertive visitare to : EEEEstablish rapport with the patient. OOOObtain a history & perform a physical examination. OOOOrder special investigations. AAAAssess the risks of anesthesia & surgery & if necessary postpone or cancel the date of surgery. AAAA physical status classification is assigned. IIIInstitute preoperative management. PPPPrescribe premedication & plan the anesthetic management.

Risk assessment : Is the patient in optimum physical condition for anesthesia? Are the anticipated benefits of surgery greater than the anesthesia & surgical risks produced by concurrent medical disease? Mortality from anesthesia ( approximately 1 in 10000). Assessment of fitness for anesthesia & surgery. ASA Grading : Medical co-morbidity increase the risk associated with anesthesia & surgery. American Society of Anesthesia (ASA) grade is the most commonly used grading system. ASA accurately predicts morbidity & mortality. 50% of patient presenting for surgery are ASA grade 1 Operative mortality for these patients is less than 1 in

ASA Grading ASA Grade Definition mortality (%) I Normal healthy individual 0.05 II Mild systemic disease that does not limit activity 0.4 III Sever systemic disease that limits activity but is not 4.5 incapacitating incapacitating IV Incapacitating systemic disease which is constantly 25 life-threatening life-threatening V Moribund, not expected to survive 24 hours with or without surgery without surgery E Emergency

Application of ASA Grading ASA Grade 2 ASA Grade 3 ASA Grade 2 ASA Grade 3 Angina Occasional use of GNT Regular use of GNT or unstable angina Hypertension Well controlled on single agent Poorly controlled,Multiple agents Diabetes Well controlled, No complications Poorly controlled or complications COPD Cough or wheeze, well controlled Breathless on minimal exertion Asthma Well controlled with inhalers Poorly controlled, limiting lifestyle Asthma Well controlled with inhalers Poorly controlled, limiting lifestyle

American Society of Anesthesiologist fasting guidelines : Ingested material Minimum fast Clear liquid 2 hours Breast milk 4 hours Infant formula 6 hours Non-human milk 6 hours Light meal 6 hours

Premedication Involves the prescription of drugs before the induction of anesthesia in order to :  Alleviate the apprehension associated with surgery.  To counteract the side effect of anesthetic agents.  To reduce the risk of pre-existing pathology. The ideal pre-medicant:  Painless to administer.  Highly reliable & specific.  Rapid onset & rapidly cleared.  Free of side effect & interactions with other drugs.

Goals for preoperative medication  Relief of anxiety & fear.  Sedation.  Amnesia.  Analgesia.  Drying of airway secretion.  Prevention of autonomic reflex responses  Prevent bronchospasm.  Prevent or minimize the impact of aspiration (Reduction of gastric fluid volume & increase PH ).  Antiemetic effects.  Reduction of anesthetic requirements.  Prophylaxis against allergic reaction.

Secondary goals for pharmacologic premedication  Facilitation of induction of anesthesia.  Postoperative analgesia.  Prevention of pon & v (iv antiemetic ). Depressant pharmacologic premedection indicated in :  Cardiac surgery.  Cancer.  Coexisting pain.  Regional anesthesia. Relative contra-indications to sedative premedication :  New born < 1 year, elderly.  Decrease level of consciousness, intracranail pathology.  Sever pulmonary patholgy.  Hypovolemia.  Airway obstruction or airway surgery, sleep apnoea.  Sever hepatic & renal disease.  Rapid sequence induction.  Obstetric anesthesia.  Day case anesthesia ( delay discharge ).

Sedation & Anxiolysis Preoperative visit by practitioner very effective, outpatient practice of today. Most patients are somewhat anxious but very few are unreasonable so ;  Bezodiazepines are logical drug for this purpose. The most popular drugs used for preoperative medication:  To produced anxiolysis, amnesia & sedation.  Little depression of ventilation, CNS, CVS with premedication doses.  A wide therapeutic index & a low incidence of toxicity.  Nausea & vomiting are not usually.  These drugs are also used before operation to reduce the unpleasant dreams & delirium that may occur after ketamine. Types of drugs : Types of drugs :  Barbiturate.  Butyrophenones.  Hydroxyzine.  Diphenhydramine.  Phenothiazine.

Analgesia If patient has painful condition or painful procedure to be performed before the induction of GA as internal jugular puncture with major cardiovascular surgery planned.  IM-Morphine mg/kg or fentanyl micrograms/kg.  IV-fentanyl 1-4 micrograms/kg with subsequent supervision. These drugs may cause or increase nausea that is already present, decrease gastric motility, cause biliary spasm. Airway secretion Anticholinergics are not necessary for reduction of secretion in every case but are very useful :  If prolong use of mask is anticipated, difficult airway, with ketamine, in smoker.  Procedure requiring instrumentation or examination of the upper airway. Antisialogogues:  Glycopyrronium.  Atropine.  Scopolamine.

Gastric fluid PH & volume Many patients who come to the operating room at risk for aspiration pneumonitis. The classic example is the patient :  With acute pain & full stomach who must have emergency surgery.  The pregnant patient.  The obese patient.  The diabetic, gastroparesis secondary to diabetes.  Hiatus hernia or gasroesophageal reflex.  Delay empty :morphine, alcoholic Prevention of aspiration pneumonia / general  The necessity of prolong fasting.  Some institution allow ingestion of clear liquids until 3 or even 2 hour before surgery in selected patient. before surgery in selected patient.  Some use NG tube before operation.  Antacide, H2 recepter antagonists, Anticholinergics, gastrokinetic agents. 

Nausea & vomiting (pon & v) Difficult to prevent especially in predisposed patient :  Higher in women than men.  Operation on eye & ear surgery, laparoscopic procedure.  Previous history of nausea & vomiting.  History of motion sickness.  Anesthetic technique (volatile maintenance more emetic than iv propofol maintenance ) General measures:  Strongly consider propofol for induction, avoid nitrous, minimize narcotic use, preoperative clear liquid, slow movement postop.  Muscarinic antagonist : hyoscine, cyclizine, promethazine.  Dopamine antagonist : prochlorperazine, droperidol, metachlopramine.  5HT. Antiserotinine Ondansetron.

AAAAlteration of autonomic reflexes: P Parasympathic stimulation can lead to hypotension, bradycardia / or even asystole mediated by the vagus nerve. TTTTriggers includes: t traction on the extraocular muscles. Surgical dilation of the cervix or of anal sphincter. Repeated doses of suxamethonium. Laryngoscopy in children. Opiod anlagesia; halothan. GGGGlycopyrronium 0.2 mg iv at induction / atropine.

 Sympathetic stimulation can lead to hypertension & increase myocardial oxygen demand … ischemia in susceptible patient.  Triggers includes: Laryngoscope & tracheal intubations. Laryngoscope & tracheal intubations. Surgical stimulation & pain.Surgical stimulation & pain. Drugs like kitamine, coccaine & adrenaline in local anesthetic agents.Drugs like kitamine, coccaine & adrenaline in local anesthetic agents.  Treatment: Clonidine in doses of 5 mg/kg.Clonidine in doses of 5 mg/kg. Opioid: fentanyl, alfentanil, sufentanil.Opioid: fentanyl, alfentanil, sufentanil. Beta blocker: proponolol, esmolol.Beta blocker: proponolol, esmolol. Xylocaine iv.Xylocaine iv.

 Prevention of bronchospasm  Patients with known bronchospasm, the following may be considered: Anticholiergics- Continue inhaled pre-op if patient taking these medications. Anticholiergics- Continue inhaled pre-op if patient taking these medications. Atropine: mg also works well but may cause significant tachycardia.Atropine: mg also works well but may cause significant tachycardia. Contiuation of oral & inhaled (beta-2 agonists).Contiuation of oral & inhaled (beta-2 agonists). Continuation / administrration of inhaled & oral steroids.Continuation / administrration of inhaled & oral steroids.