Anaesthesia detailed ppt medical surgery

Ppt on anaesthesia

1. Anaesthesia GUIDED BY : BY Dr : Nalini M : Lingaraj A B HOD Shalyathantra : Sanjay Y

2. Anaesthesia Defination ; Anesthesia or anaesthesia is a state of controlled, temporary. An individual under the effects of anesthetic drugs is referred to as bloss of sensation or awareness that is induced for medical purposeseing anesthetized

3. Surgery has been practised for ages. However, the advent of modern techniques of anaesthesia has allowed surgery to develop by leaps and bounds. If there is a well-informed, vigilant and safe anaesthesiologist taking care of the patient, the surgeon is able to concentrate on the surgical procedure unhindered. IMPORTANCE

4. PREOPERATIVE ASSESSMENT AND PREMEDICATION . Anaesthesia is associated with changes in the internal homeostasis. Normally these are well tolerated by the different systems. However, if the patient has a pre-existing derangement, his capacity to withstand changes in his internal milieu may be limited. It is thus very important to know the preoperative condition of the patient.

5. History A detailed history of the patient with symptoms pertaining to the various systems must be elicited Physical examination A detailed physical examination is done and the relevant history specially borne in mind. General physical examination includes Vital signs: Blood pressure, heart rate, respiratory rate, temperature (and oxygen saturation, in relevant cases) PICCLE: Pallor, icterus, cyanosis, clubbing, lymphadenopathy, oedema . Airway: Examine carefully to detect any difficult airway Spine: To rule out infection over the skin covering the spine, tenderness, stiffness or fractures of spine, to check spaces.

6. Systemic examination I . Cardiovascular system Dyspnoea, angina, syncope, palpitations, pedal oedema, previously diagnosed to have a cardiac problem, effort tolerance 2.Respiratory system Cough, fever, breathlessness, chest pain, recent onset upper respiratory tract infection 3. Central Nervous System;Consciousness level, convulsions, orientation, ability to walk, speech, movement of all four limbs, bowel and bladder habits, any paraesthesia or altered sensation in the limbs. 4. Renal system; Decreased urine output, haematuria 5. Hepatic: Jaundice

7. 8 Previous medical history: Previous surgeries/ anaesthetics , any problems during the previous experience. H/o hospitalisation in the past 9 Allergy: Allergy to any drug or other substances 10 Addictions Smoking, alcohol, drug abuse 11Pregnancy Last menstrual period/possibility of pregnancy (in female patients) 12Family Relevant family history, particularly pertaining to anaesthesia

8. Assessment of airway Whenever a person becomes unconscious, the tongue and epiglottis fall back on to the pharynx and obstruct the airway. Since the anaesthesiologist makes the patient unconscious during a general anaesthetic , it is his duty to ensure that the patient's airway patency is maintained. Hence, assessment of the airway becomes important before a patient is made unconscious .

9. Investigations Haemoglobin estimation ECG Blood sugar estimation Blood urea Chest X Ray Informed Consent

10. TYPES OF ANAESTHESIA They are classified into 2 categories 1 General Anaesthesia 2 Local Anaesthesia

11. General Anaesthesia The patient is unconscious and there is a generalised and reversible depression of the central nervous system . REGIONAL ANAESTHESIA This involves injection of local anaesthetic agents in close proximity to the nerves or nerve bundles supplying the site of surgery. Regional anaesthesia can be central neuraxial block or peripheral nerve blocks.

12. The choice of anaesthesia depends on several factors : The site and duration of surgery General condition of the patient Expertise of the anaesthesiologist and

13. GENERAL ANAESTHETIC AGENTS 1 Hypnosis Ex Lorazaoem Diazepam Dose -250 mg Route-IV 2 Amnesia Ex Midazolam Anxiolytics Dose -0.03 to 0.06mg/kg 3 AnalgesiaEx Codine MethadoneDose -10mgRoute -IV)ORAL

14. General anaesthetic agents are of two main types Inhalational anaesthetic agents intravenous anaesthetic agents. INHALATIONAL ANAESTHETIC AGENTS • Volatile anaesthetics: The volatile anaesthetic agents need a vaporiser to calibrate and deliver the vapour accurately in measured doses e.g. halothane Nonvolatile anaesthetics: e.g. nitrous oxide

15. INTRAVENOUS ANAESTHETIC AGENTS Intravenously administered anaesthetic agents are more popular for induction of anaesthesia because it is more rapid and smooth than that associated with inhalational agents They can be classified into Rapidly-acting Ex thiopentone Profol Dose -4mg/kg Route -IV Slow-acting Slow actingEx Ketamine Benzodiazepines Dose 2mg/kg Route -IV

16. MONITORING IN ANAESTHESIA The administration of anaesthesia is associated with changes in the internal homeostasis of the patient, especially the cardiac and respiratory systems. Constant monitoring of the various body systems is necessary to ensure the well-being of the patient. Monitoring used in anaesthesia may be classified into: noninvasive and invasive monitoring

17. NONINVASIVE MONITORING Basic noninvasive monitoring includes clinical observation of the patient Adequate cardiac output. Heart rate Blood pressure INVASIVE MONITORING Direct Arterial pressure monitoring Central venous pressure monitoring

18. LOCAL ANAESTHESIA Local anaesthetics are drugs when injected around the nerves block impulse conduction distal to the site of injection and produce analgesia and anaesthesia in that area . They are classified into two main categories Aminoesters : Procaine, chloroprocaine , tetracaine Aminoamides : Lignocaine, bupivacaine, ropivacaine Local anaesthetic exists in two forms: Ionised and nonionised . The nonionised form is lipophilic and crosses the phospholipid membrane more easily. The ionised form is hydrophilic and blocks the channel in the open state and blocks nerve transmission

19. Factors influencing activity Higher the lipid solubility, higher is its ability to penetrate the lipoprotein membrane and hence greater is its potency . Toxicity of local anaesthetics If significant amount of local anaesthetics reach the tissues of heart and brain, they exert the same membrane stabilising effect as on peripheral nerve, resulting in progressive depression of function. The toxicity of local anaesthetics is dose-dependent. These drugs always produce central nervous system (CNS) toxicity first. As the plasma level rises, cardiovascular toxicity and collapse occur. bupivacaine has a greater potential for cardiotoxicity.

20. Clinical features of local anaesthetic toxicity The clinical effects and their relation to plasma level Plasma CNS toxicity Concentration (µg/ml) 5 Tingling, numbness, tinnitus, light- 5-10 Slurred speech, muscle twitching 10 Loss of consciousness 10-15 Convulsions 15 Coma 20 Respiratory arrest

21. toxicity of local anaesthetics depends on several factors 1. Amount of drug injected 2. Site of injection-vascularity 3 . Addition of vasoconstrictors 4 . Rapidity of injection 5. Nature of drug given 6. Presence of associated conditions such as low cardiac output or renal failure.

22. Prevention of toxicity Do not exceed recommended doses Avoid injecting large boluses at once. Small boluses, given slowly to achieve the desired effect are safer.

23. Treatment of local anaesthetic toxicity The toxicity of local anaesthetics manifests as CNS depression and convulsions. Maintenance of airway, breathing and circulation must be a priority. These convulsions generally last for a short period of time. • Patency of the airway must be maintained. • Oxygen by face mask. • Ventilation, if apnoea occurs. • Convulsions are treated with intravenous diazepam or thiopentone in incremental doses. • Cardiovascular collapse with ephedrine, inotropes and vasoconstrictors, and CPR as needed.

24. SPINAL AND EPIDURAL ANAESTHESIA When the local anaesthetic is injected into the cerebrospinal fluid bathing the spinal cord, it is called spinal anaesthesia (subarachnoid block). When the local anaesthetics are injected into the epidural space to block the nerves that emerge from the spinal cord, it is called epidural anaesthesia .

25. Spinal anaesthesia I. Done in the lumbar region only 2 . Confirmation of correct placement of needle by ensuring free flow of CSF 3. A small amount of local anaesthetic is used 4. Onset of neural blockade is fast. So also side-effects 5. All the nerves are blocked below the level of anaesthesia 6. Limited duration. Continuous spinals are not routinely used

26. BRACHIAL PLEXUS BLOCK Injection of local anaesthetics injected around the brachil plexus produces analgesia and even surgical anaesthesia is the upper limb. The brachial plexus can be blocked by fou different approaches: interscalene , supraclavicular, infra clavicular or the axillary. Of these, the supraclavicular and the axillary techniques are the most popular . Drugs • Lignocaine plain not exceeding 5 mg/kg • Lignocaine with adrenaline 7 mg/kg or • Bupivacaine not exceeding 2.5 mg/kg may be used.

27. Indications • Intraoperative analgesia and postoperative pain relief in adults and children. • Sole anaesthetic in adults for procedures on the upper limb. Contraindications • Absence of consent • Local infection • Bleeding tendencies Complications • Haematoma • Intravascular injection of local anaesthetics • Pneumothorax.

28. COMPLICATIONS IN ANAESTHESIA The practice of anaesthesia has become very safe due to better preoperative evaluation and preparation, careful choice of patients, better monitoring, availability of safer drugs and safer anaesthetic techniques. The incidence of complications has come down drastically. However complications can still occur. The perioperative (pre-, intra-, and postoperative periods) complications can be classified as follows :

29. Complications of general anaesthesia Respiratory Airway obstruction Bronchospasm Respiratory failure. Cardiovascular Hypertension

30. Complications of Local anaesthesia Head ache Blured vison Shivering Weekness

31. Some importatant questions 1Types of local anaesthesia 2 Spinal anaesthesia,its indication, contraindications and complications 3 local anaesthetic drugs 4General anaesthesia 5 Epidural and spinal anaesthesia

32. THANK YOU