GENERAL AND REGIONAL ANAESTHESIA Katarina Zadrazilova FN Brno, 2014 ..aims •What do anaesthetists do •Basic anaesthetic management •Drugs, gases, monitoring, machines The role of anaesthetist •Ensures safe anaesthesia for surgery •Is responsible for patient safety in theatre •Ensures the anaesthetic machine and drugs are checked and correct •Liase with the surgeon and scrub team – ensure that the operation can proceed smoothly •Keep an anaesthetic record •Makes a postoperative plan Anaesthetic plan •Preoperative •Intraoperative •And postoperative management Anaesthetic plan •Preoperative •Intraoperative •And postoperative management Preoperative management •Anaesthetic assessment :history and examination •Relevant investigations : lab, CXR, ECG •Optimise chronic condition •Plan for intra and post op pain refief •Discuss ev. HDU/ICU post op bed for patient •Consent the patient •Prescribe premedication • Anaesthetic assessment •Previous surgery (GA, LA, complications) •Medical hx, Medication, FH •Allergies •Last meal, drink ! •Teeth •Pregnancy •Examination: airway assessment, neck, back + general physical exam. • Risk assessment – ASA grade •I Healthy patient •II Mild systemic disease, no functional limitations •III Severe systemic disease- definite functional limitation •IV Severe systemic disease that is a constant threat to life •V Moribund patient not expected to survive 24 hours with or without operation Premedication •Sedation/anxiolysis (Benzodiazepines) •Analgesia only if pain (opioids) •Reduce airway secretions + heart rate control + hemodynamic stability •Prevent bronchospasm •Prevent and/or minimize the impact of aspiration •Decrease post-op nausea/vomiting Consent •Discuss all options GA/regional •Risks versus benefits •Complications – common, rare and serious •Make pain relief plan Complications ▫NO RISK = NO ANAESTHESIA ▫ •Common (someone in a street) ▫PONV, sore throat, backache, headache, dizziness • •Rare and serious (someone in a big town) ▫Damage to the eyes, anaphylactic shock, death, equipment failure Mortality of anaesthesia (ASA I) •Risk of death or brain damage ▫1: 100 000 – 200 000 • •Dying in a plane crash ▫1 : 200 000 •Dying in a car crash ▫1 : 5000 Anaesthetic plan •Preoperative •Intraoperative •And postoperative management Teamwork ! anaesthetist ODP surgeon scrub nurse Operating theatre •Allow surgery, ECT • •Allow diagnostic method (CT, MRI) Anaesthesia = loss of sensation •General (narcosis) •Local / regional • •Combined Anaesthesia = loss of sensation •General (narcosis) •Local / regional • •Combined AIMS OF ANAESTHESIA Triad of anaesthesia •Neuromuscular blocking agents for muscle relaxation •Analgesics/regional anaesthesia for analgesia •Anaesthetic agents to produce unconsciousness Stages of anaesthetics •Induction – putting asleep •Maintenance – keeping the patient asleep •Reversal – waking up the patient • • Intravenous anaesthetics •Onset of anaesthesia within one arm – brain circulation time – 30 sec •Effect site brain ▫Propofol ▫Thiopentale ▫Etomidate Anaesthetic gases •Isoflurane •Sevoflurane • •Halothane •Enflurane •Desflurane • •N2O – nitrous oxide Inhalational anaesthetics Anaesthetic gases •Used for maintainance, sometimes induction • •Anaesthetic ‘gases’ are administered via ▫ vaporizers • Inhalational anaesthetics Induction + maintenance Intravenous anaesthetics Muscle relaxants - NMBs •Tracheal intubation •Surgery where muscle relaxation is essential •Mechanical ventilation • •Place of effect - neuromuscular junction •History - South American Indians (kurare) • Neuromuscular blocking agents Analgesics •Simple : paracetamol, NSAID •Opioids : morhine, fentanyl ▫Via opioid receptors MORPHEUS- GREAK GOD OF DREAMS Monitoring •Basic: ▫NIBP, ECG, Sat, ETCO2, FiO2 • •Extended: ▫Nerve stimulator, temperature, diuresis, IBP, CO, CVP, perioperative acid-base, lab Standard monitoring ECG Non-invasive Blood Pressure Invasive Pressure Monitoring Gas Analysis Pulse Oximetry: Peripheral Nerve Stimulation: •Mix gases, ventilate, preserve heat and moisture •High pressure • central gas supply/ cylinder •Low pressure system •Flowmeters •Vaporisers •Breathing circuit: ▫bag + tubes ▫valves (uni directional) ▫CO2 absorber •Ventilator Anaesthetic machine Airway management •Indication for intubation: •Need of relaxation or PPV •Full stomach • •Orotracheal intubation, nasotracheal intubation with direct laryngoscopy •Tracheotomy •Laryngeal mask •Cricothyreotomy INTUBATION - Always consider why you are exposing the patient to the risk, albeit small, of intubation- a.) protection from gastric aspiration and secretions b.)access and maintenance-in difficult airway and difficult surgical positions/procedures c.) provide positive pressure ventilation- can be done for shorter periods with a mask or LMA d.) oxygenation- to provide a controlled concentration of oxygen up to 100%, also provides for complete scavenging e.) secretions- facilitates removal of secretions via suctioning Intubation Laryngeal Mask Anaesthesia = loss of sensation •General (narcosis) •Local / regional • •Combined Local anaesthetic •Reversible block • •Sodium ion canal (Na+ to cell) • •A: myelinated ▫a (alfa): motor function, reflex activity a proprioception ▫b (beta): touch, pressure ▫g (gama): muscular tonus ▫d (delta): PAIN and sense of heat •B: thin, myelinated preganglion-nerve fibre, autonomic function, smooth muscle of vessels •C: non-myelinated, PAIN Nerve fibre •Somatic sensory - loss of cutaneous sensation (numbness), proprioception •Motor nerve - loss of movement ▫(if it is a motor nerve) in the distribution of the peripheral nerve • Autonomic nerves - vasodilation and warmth What does the block of nerves lead to? > Local anaesthetics •Potentially toxic! •CNS ▫Convulsion, coma, depression of breath! –Perioral tingling, iron taste, somnolence, vertigo, tinitus (ringing), nystagmus, visual disturbance •Cardiovascular system ▫Hypotension, bradycardia, colaps of circulation, asystoly or ventricular fibrilation! Local anaesthetics •Esters •Amides • •Examples: lidokain, trimecain (Mesocain), • bupivakain (Marcaine), prokain, • artikain (Ultracain, Supracain), • ropivakain (Naropin) Use of RA •Analgesia, e.g. fractured femur, fractured ribs •As the sole anaesthetic for surgery with or without sedation, e.g. hand surgery •In combination with GA, e.g. total knee replacement •For postoperative analgesia • When to use regional techinques 1.Patient safety – frail elderly, comorbidities 2.Patient satisfaction – ealy oral intake, no PONV, no sore throat 3.Surgical outcome - awake craniotomy • Most common regional anaesthesia •Caesarian section ▫Patient safety –Control of airway ▫Patient satisfaction –Awake during the delivery of the child –Presence of partner ▫Surgical outcome –Intraoperative bleeding is reduced –Reduced stress response Local anaesthesia •Local anaesthesia ▫ Superficial (topic, mucosa) ▫ ▫Infiltration • 1_01 4_12 Neuroaxial blocks Central neuroaxial block •Indication: ▫Surgery bellow umbilicus ▫Combined anaesthesia for abdom. surgery ▫Continual technic for postoperative pain relief ▫Labour analgesia and anaesthesia •Contraindication ▫Patient´s refusal ▫Local infection ▫Hypotension, hypovolemia, shock ▫Valve stenosis - fixed cardiac output ▫Coagulopathies (warfarin, heparin) Systemic effect of central blockade •Cardiovascular system ▫Sympathetic block –Hypotension –Reduced venous return –Relative hypovolemia •Ventilation: small influence •Urination: urinary retention 3_02 3_04 3_05 3_03 Lumbal epidural block [USEMAP] Peripheral blocks •Single nerves •Nerve plexuses Plexus brachialis 1_01 1_03 Stimulator 3_15 Anaesthetic plan •Preoperative •Intraoperative •And postoperative management Postoperative care •ICU/HDU or ward •Monitoring according to type of surgery and patient’s condition •Post-operative pain control •Lab check up •Infusion therapy, blood loss monitoring Questions ? ana_1_075_anaphylaxis_13_01_med