Pre-anesthetic Medication (Premedication) - Al-Noor University College - PDF

Al – Noor University College Department of anesthesiology ‫) ﺍﻟﻤﺮﺣﻠﺔ ﺍﻟﺜﺎﻧﻴﺔ‬3(‫ﻣﺤﺎﺿﺮﺓ ﺗﺨﺪﻳﺮ‬ ‫ ﻧ ﺰ ﺍ ﺭ ﺍ ﻟ ﺤ ﻴ ﺎ ﻟﻲ‬. ‫ﺩ‬ Pre-anesthetic medication) premedication) It is the term applied to t...

Al – Noor University College Department of anesthesiology ‫) ﺍﻟﻤﺮﺣﻠﺔ ﺍﻟﺜﺎﻧﻴﺔ‬3(‫ﻣﺤﺎﺿﺮﺓ ﺗﺨﺪﻳﺮ‬ ‫ ﻧ ﺰ ﺍ ﺭ ﺍ ﻟ ﺤ ﻴ ﺎ ﻟﻲ‬. ‫ﺩ‬ Pre-anesthetic medication) premedication) It is the term applied to the administration of drugs prior to the general anesthesia so as to make anesthesia safer for the patient and to minimize adverse effects of anesthesia. The aims of pre-medication are: 1- Relief anxiety and apprehension preoperatively and facilitate smooth induction of anesthesia and potentiate the action of anesthetic drug so less dose is needed 2-. Reduce postoperative nausea and vomiting 3- Reduce salivary and bronchial secretions; 4- - Produce analgesia before surgery and provide a background of analgesia during operation and early 7  postoperative period. 5- - Produce amnesia. 6- Reduce volume and increase the pH of gastric acid secretion and prevent aspiration. 7- To reduce the undesirable vagal reflexes e.g. sever bradycardia. 8- Maintain hemodynamic stability. Premedication is usually given intramuscularly 1-3hr. pre- operatively and also can be given orally at the night of operation. Route of administration: 1- Orally 2- Intramuscular 3-intravenous 4-intranasal 5- Dermal Factor to be considered before premedication 1-Patient’s Physical status 2- Age 3- Level of anxiety and pain 7  4- Type of Surgery 5- Time of surgery 6- History of drug allergy, nausea, vomiting Anxiolytics, sedation and amnesia: Careful discussion of the patient's concerns is essential, including the pre-operative assessment. Sedation is a ranging from minimum anxiolytic to a state of deep sedation but not including G A. Drugs Used for Sedation 1- Benzodiazepines: are the usual agents used as they provide anterograde amnesia, relief of anxiety and light sedation. If given orally 1-2 hours before surgery they have only a small effect on cardiorespiratory function but large doses can result in delay recovery. In day-case surgery, short-acting benzodiazepines (eg, temazepam) are often preferred. Temazepam is given orally; the dose is 20-40 mg.30-60 min. before surgery Lorazepam is longer acting and effective for amnesia. 2 mg i.m. 7 Midazolam is also commonly used, and is associated with a faster recovery time than diazepam, Dose: 1 - 2.5 mg slow IV Diazepam dose 5-10 mg orally. Its uses are not recommended for premedication in children. 2- Barbiturates: e.g.: phenobarbitone 30 mg. orally 3- Promethazine 25 mg. i.m. Amnesia: Especially in the young patient or those having repeated surgery. The most effective agent is Lorazepam and midazolam Factors limiting giving sedatives 1-Extremes of age. 2-Head injury 3- Minimal cardio- pulmonary reserve 4- Hypovolemia. 5- Full stomach. Analgesia: Analgesic drugs given pre-operatively reduce the preoperative acute severe pain also reduce the required dose of anaesthetic agent and to provide postoperative analgesia. Analgesic drugs used include: opioids, paracetamol, non-steroidal 7 anti-inflammatory drugs (NSAIDs). NSAIDs are commonly used, particularly in day surgery, unless there are contra-indications. Opioids are usually the agents of choice in the presence of acute severe pain. Opioids also cause variable sedation and cardiorespiratory depression. All opioids can cause nausea and vomiting. Opioids may also precipitate bronchospasm or anaphylaxis. 1-Opioids drugs include: Morphine 8-12 mg. i.m. Pethidine 50-100 mg. i.m. Fentanyl 0.05-0.1 mg. I.m. or i.v. 2- NSAIDS: e.g. Diclofenac 50- 75 mg. orally or i.m. 3- Paracetamol 500 mg orally Anti-emetics: Antiemetic drugs are used to reduce the incidence of postoperative nausea and vomiting (PONV). Aspiration 7 Risk Factors for Aspiration 1- Emergency cases 2- Type of surgery 3- Recent meal 4- Trauma 5- Pregnancy 6- Pain and stress Preventative measure for nausea and vomiting: 1- Fasting 2- Reduce gastric volume, and Increase gastric PH: this is done by : a) H2 receptor antagonist eg. Ranitidine 150-300 mg. orally or famotidine 20-40 mg. Orally given at the night of operation b) Proton pump inhibitor e.g. omeprazole 20-40 mg, given 3-4 hrs. Preoperatively. c) Antacid such as sodium citrate 15-30 minutes before induction. 3- Increase gastric motility Metoclopramide 10 mg. given i.m. used as anti-emetic and as prokinetic gastric emptying agent prior to emergency operation. 7 Domperidone 10 mg. orally also can be used. Anti –salivary and Anti-vagal effect: Anticholinergic drugs are given to reduce salivary and bronchial secretion, and to reduce the undesirable vagal reflex (eg. Bradycardia, and hypotension.) Atropine 0.5 mg. i.m. Hyoscine 0.5 mg. i.m Continuation and discontinuation of drugs before surgery: Continuation Beta blocker including Ant hypertension Bronchodilators Anti- epileptics , Insulin Discontinuation MAO-inhibitors Anti-coagulants Oral hypoglycemic ACE inhibitors Aspirin. oral contraceptive. 7