Premedication Anesthesia Techniques PDF

# Premedication **Al-Nukhba University College** **Anesthesia Techniques** **2^nd grade** **Anesthesia 1** **Date:** 9/11/2024 **Duration:** two hours **Lec.no:** 3 **BY:-** **Dr.Baydaq F.Mirza** **MBChB,FICMS/ANESTHESIA.IC** ## Introduction **Preoperative medication consists of:** -...

# Premedication **Al-Nukhba University College** **Anesthesia Techniques** **2^nd grade** **Anesthesia 1** **Date:** 9/11/2024 **Duration:** two hours **Lec.no:** 3 **BY:-** **Dr.Baydaq F.Mirza** **MBChB,FICMS/ANESTHESIA.IC** ## Introduction **Preoperative medication consists of:** - psychological - pharmacological preparation. **How the patient should be like before entering OT:** - free from apprehension - sedated - arousable - cooperative. ## Goals of preoperative medication - Relief of anxiety - Sedation - Amnesia - Analgesia - Drying of airway secretions - Prevention of autonomic reflex response - Reduction of gastric fluid volume and increased pH - Antiemetic effects - Reduction of anesthetic requirements - Facilitation of smooth induction of anesthesia - Prophylaxis against allergic reactions. ## Psychological preparation **Non-pharmalogical antedote to apprehension:** - preoperative visit - interview ## Adminstration of premedication - 1-2 hr before the surgery - night before. ### Prescribed medications: - 2 hours prior to surgery - small sip of water (<30ml) orally ## I. Anxiolytics / Sedative / Hypnotic ### Benzodiazepines (still commonly used) - Diazepam - Lorazepam - Midazolam - Alprazolam ### Barbiturates (not used much) - Secobarbital - Pentobarbital ## Midazolam - Water soluble benzodiazepine with painless administration - Amnesic effects are more potent than sedative effects. - choice of drug for out patient surgery and pediatric premedication - Capable of crossing the BBB with effects ranging from tranquillization to full anesthesia. - Respiratory depressant - Hazardous in hypovolemic patients. - Patients with decreased intracranial compliance show little or no change in ICP with midazolam ## II. Opioid analgesics - Morphine - Pethidine - Fentanyl **They differ in duration of action; can be given parentally.** - administered preoperatively for sedation - control hypertension during tracheal intubation - analgesia ## Fentanyl - Potent narcotic analgesic; 100 times more potent than morphine - Metabolised in liver and excreted through urine and feces - Respiratory depression and rigidity of respiratory muscles which can be satisfactorily treated with naloxone **For preoperative analgesia, the use of IV fentanyl is preferred :** - rapid onset - short duration - Fentanyl is also available as transdermal patches. ## III. Anticholinergic drugs **Three drugs are in use as preanesthetic:** - Atropine - Hyoscine - Glycopyrrolate **While the first two are tertiary amines that cross the BBB, glycopyrrolate is a quateranry amine which does not cross BBB and is not absorbed from GI tract.** ## Clinical effects of anticholinergics - **Antisialogogue effects:** Glycopyrrolate and hyoscine are more potent than atropine, reduce secretions and bradycardia after succinylcholine - **Sedative and amnesic effect:** In combination with morphine, hyoscine produces powerful sedative and amnesia effects - **Prevention of reflex bradycardia:** Atropine is used to prevent oculocardiac reflex in eye surgery and is used to prevent halothane bradycardia ## Side effects of anticholinergics - **CNS toxicity:** Atropine produces central anticholinergic syndrome of the CNS, producing restlessness, agitation, somnolence and convulsions - **Physostigmine** 1-2 mg /V reverses the effects when given with glycopyrrolate - Reduction in lower oesophageal sphincter tone - Tachycardia & Hyperthermia - Mydriasis and cycloplegia - Unpleasant and excessive drving of mouth ## V. Prevention of pulmonary aspiration - No drug or combination is absolutely reliable in preventing the risk of aspiration - Patients with no apparent risk of aspiration, these drugs are not recommended - Cimetidine and Ranitidine are the two drugs in common clinical use which when used as premedication may increase the gastric pH higher than 2.5 and decrease the gastric volume < 25 mL ## Factors predisposing to aspiration: - Emergency surgery - Inadequate anesthesia - Abdominal pathology - Obesity - Opioid premedication - Neurological deficit - Lithotomy - Difficult intubation/airway - Hiatal hernia ## Summary of fasting recommendations to reduce the risk of pulmonary aspiration | Ingested material | Minimum fasting period (hrs) | |---|---| | Clear liquids | 2 | | Breast milk | 4 | | Infant formula | 6 | | Non human milk | 6 | | Light meal (toast and clear liquids) | 6 | ## Premedication in pediatric patient - Includes age-specific psychological preparation and an emphasis on oral medications when sedation is desired. - Topical anesthetic creams are often prescribed for children before cannulation ## Preop Medication instruction guideline **Medication to be continued on day of Surgery:** - Anti hypertensive - Diuretics - Cardiac medication - Antidepressant – antianxiety - Thyroid, asthma medication - Steroids (oral & inhaled) ## Medications to be discontinued before surgery - Aspirin: * 7 days before surgery - NSAIDs: * 48 hrs before plastic retinal surgery - Oral hypoglycemic drugs: * on the day of surgery - Insulin: * 1/3rd dose in morning - Warfarin: * 4 days before surgery - Heparin: * 4 – 6 hrs before surgery - MAO inhibitors: * 2 weeks before surgery ## Conclusion ## Q&A