Anesthesia and Pain Control Medications ppt

Risk Factors Affecting Pain Control in Perioperative Settings

• Preoperative pain is known to negatively impact postoperative outcomes.
• Anxiety prior to surgery can exacerbate pain perception and discomfort.
• Genetics can play a role in individual pain responses and susceptibility to chronic pain.
• Opioid tolerance can result in inadequate pain relief from standard doses.
• Females generally report higher levels of perioperative pain compared to males.
• Pain involves inflammatory and neuropathic components that can influence its management.
• Central and peripheral sensitization mechanisms contribute to chronic neuropathic pain.

Anesthetic Requirements

• Increased anesthesia needs can stem from chronic alcohol use, infancy, red hair (likely due to genetics), dehydration, and hyperthermia.
• Decreased requirements may occur in acute alcohol use, elderly patients, hyponatremia, hypothermia, severe anemia, hypercarbia, hypoxia, and during pregnancy.

Drug Therapy Used for Anesthesia

• Pre-anesthetic medications include benzodiazepines, barbiturates, antihistamines, and phenothiazines to mitigate anxiety and pain.
• Inhalational anesthetics and intravenous anesthetics like barbiturates, etomidate, and propofol are core to anesthesia practices.
• Neuromuscular blocking agents are administered at the end of the anesthetic process to facilitate procedures such as intubation.

Benzodiazepines

• Act quickly, help reduce anxiety, and enhance the safety profile of local anesthetics.
• Agents include:
  • Diazepam: prolonged action.
  • Lorazepam: intramuscular and intravenous options.
  • Midazolam: rapid onset and short duration, ideal for procedures like colonoscopies.

Barbiturates

• Rapid sedative effect, but can lead to disorientation, especially in pain contexts.
• Example agents include pentobarbital and thiopental, which may cause cardiac and respiratory depression.

Inhalational Anesthetics

• Used for induction but provide minimal analgesia.
• Agents such as nitrous oxide, sevoflurane, and isoflurane are effective but can have adverse effects like nausea and malignant hyperthermia.

Dexmedetomidine

• An alpha-2 receptor agonist with sedative, anxiolytic, and analgesic properties, used primarily in ICUs and brief procedures.

Etomidate

• Rapid-acting hypnotic agent with no analgesic properties, commonly used during intubations and for conscious sedation.

Ketamine

• Provides dissociative anesthesia and is effective for pain management, especially in emergency situations.
• An adverse effect includes potential hallucinations.

Opioids

• Function primarily through mu receptors to inhibit pain signals.
• Commonly used opioids include morphine, fentanyl, and hydromorphone, with known risks of respiratory depression and constipation.

Local Anesthetics

• Block sodium channels to interrupt nerve signal conduction.
• Two types: amino amides (e.g., lidocaine, bupivacaine) and amino esters (e.g., procaine).
• Can be used for infiltration or nerve blocks in surgeries.

Regional Anesthesia Techniques

• Epidural anesthesia involves injection into the epidural space and is often used during labor.
• Spinal anesthesia injects local anesthetic into the cerebrospinal fluid, typically for lower body surgeries.

Post-operative Nausea and Vomiting (PONV)

• PONV incidence ranges from 22% to 38%, with several risk factors including gender, prior history, and opioid use.
• Multimodal prevention strategies are essential, incorporating both pharmacologic and non-pharmacologic therapies.

Pharmacologic Treatments for PONV

• Effective agents include serotonin antagonists (e.g., ondansetron), neurokinin inhibitors (e.g., aprepitant), and steroids (e.g., dexamethasone).
• Antihistamines and butyrophenones are also used, with sedative side effects in the latter.

Summary

• Comprehensive pain management in the perioperative period utilizes a variety of anesthetic techniques and medications, including local, regional, and systemic approaches.
• Multimodal strategies to prevent PONV and improve overall patient experience are crucial for favorable surgical outcomes.