8 General Anesthetics.ppt.pptx pharmacology

**Title: General Anesthesia: An Overview**

**Description:**

Welcome to this comprehensive presentation on general anesthesia. This PowerPoint aims to provide a thorough understanding of the principles, practices, and considerations associated with general anesthesia in medical settings.

**Key Topics Covered:**
- **Introduction to General Anesthesia:** Definition, history, and significance in modern medicine.
- **Mechanism of Action:** How general anesthetics work at the molecular level to induce unconsciousness and analgesia.
- **Types of Anesthetics:** Overview of different agents used, including inhalational and intravenous anesthetics.
- **Administration Techniques:** Methods of delivering anesthetic agents and monitoring patients during anesthesia.
- **Preoperative Assessment:** Important considerations and patient evaluations before administering general anesthesia.
- **Intraoperative Management:** Techniques and strategies for maintaining anesthesia and managing potential complications.
- **Postoperative Care:** Recovery process, monitoring, and addressing common side effects or complications.
- **Safety and Risks:** Potential risks associated with general anesthesia and strategies to minimize them.
- **Recent Advances:** Latest developments and research in the field of general anesthesia.

This presentation is designed for medical students, practitioners, and anyone interested in gaining a deeper insight into the field of anesthesiology. It combines fundamental concepts with practical information, making it a valuable resource for both learning and reference.

1. General Anesthetics Dr.Sajjad Ali DPT(RIU),MS-OMPT*(RIU)

2. General Anesthetics Anesthetics are categorized as general or local, depending on whether or not the patient remains conscious when the anesthetic is administered.

3. Ideal anesthetic agent Loss of consciousness and sensation. Amnesia (i.e., no recollection of what occurred during the surgery). Skeletal muscle relaxation 4 . Inhibition of sensory and autonomic reflexes. 5. A minimum of toxic side effects 6 . Rapid onset of anesthesia

4. Stages of depth General Anesthesia Stage I . Analgesia. The patient begins to lose somatic sensation but is still conscious and somewhat aware of what is happening. Stage II . Excitement (Delirium). The patient is unconscious and amnesiac but appears agitated and restless.

5. Stages and depth of General Anesthesia Stage III. Surgical Anesthesia. this level is desirable and begins with the onset of regular, deep respiration. Stage IV. Medullary Paralysis. cessation of spontaneous respiration and cardiovascular collapse ensues . If this stage is inadvertently reached during anesthesia , respiratory and circulatory support must be provided or the patient will die.

6. Route of Administration IV: rapid onset, poor/lack of control of dose adjustment. Inhilational : Delayed onset and good adjustment. So, combination of both…at first IV then Inhilational .

7. Inhalation Anesthetics Gas/ Volatile liquid. Must be easily absorb in air/Oxygen. Easily adjusted. Given through Mask. Volatile liquids Halothane Isoflurane Methoxyflurane Desflurane & Sevoflurane newer agents. Gas Nitrous oxide (nitrogen monoxide)

8. Intravenous Anesthetics Barbiturates Methohexital Thiopental Fast and safe. Benzodiazepines Diazepam Lorazepam Midazolam Opioids Fentanyl derivatives Hydromorphone Meperidine Morphine Nalbuphine Oxymorphone Pentazocine

9. Pharmacokinetics Highly lipid soluble…easily distributed. Stored in adipose tissues…slow release. Biotransformation in Liver. Eliminated through lungs/kidneys. If pulmonary / hepatic disease…delayed elimination.

10. Mechanisms of Action Increase GABA activity Decrease acetylcholine activity Dec. transmission in nociceptive pathways. Inhibit excitatory effects of glutamate.

11. Mechanisms of Action decrease activity of neurons in the reticular activating system in the brain…produce unconsciousness and lack of memory (amnesia) during surgery. Inhibit neuronal function in the spinal cord…produce immobility and inhibit motor responses to painful stimuli .

12. Adjuvent in General anaesthesia Preoprative medicines NM blockers

13. PREOPERATIVE PREMEDICATION: Sedatives: Benzodiazepines : Decrease anxiety and tension; provide sedation and amnesia Opioids : Decrease anxiety; facilitate induction of anesthesia Antihistamines : sedative & antiemetic effects. Antacids : Reduce gastric acidity .

14. Neuromuscular Blockers Uses proper positioning on the operating table Action By blocking the postsynaptic acetylcholine receptor located at the skeletal neuromuscular junction.

15. NM blockers Tubocurarine (long) Atracurium ( int ) Doxacurium (long) Mivacurium (short) Pancuronium (long) Succinylcholine ( ultrashort )

16. Neuromuscular Blockers Adverse effects Tachycardia Muscle pain and weakness Residual paralysis

17. Residual effects the residual effects are attributed to genetic differences in the enzymes responsible for metabolizing the neuromuscular blocker.If these enzymes are deficient or absent, the patient cannot adequately metabolize the blocker, hence paralysis continues for days or even weeks. In other patients, residual effects may occur if the patient has a concurrent neuromuscular condition such as a spinal cord injury, peripheral neuropathies, intracranial lesions , or muscle pathologies.

18. THANK YOU