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. OXICITY 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.

26. 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

27. 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.

28. 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.

29. 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:

30. COMPLICATIONS OF GENERAL ANAESTHESIA
• Respiratory
• Airway obstruction
• Bronchospasm
• Respiratory failure.
• Cardiovascular
• Hypertension

31. COMPLICATIONS OF LOCAL ANAESTHESIA
• Head ache
• Blured vison
• Shivering
• Weekness

32. 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