Medication Summary
The aims of premedication are to reduce morbidity, prevent complications, and minimize myocardial oxygen demands by reducing heart rate and systemic arterial pressure.
Anxiolytics, Benzodiazepines
Class Summary
Administration of intravenous midazolam in the operating room can reduce anxiety, tachycardia, and hypertension.
Midazolam
Midazolam is a short-acting benzodiazepine with a rapid onset of action. It depresses all levels of the CNS (eg, limbic and reticular formation), possibly by increasing activity of GABA.
Opioid Analgesics
Class Summary
Induction of anesthesia is accomplished by using high doses of opioid (usually fentanyl or alfentanil) to maximize cardiovascular stability.
Fentanyl citrate (Duragesic, Abstral, Actiq, Fentora, Onsolis)
Fentanyl citrate is a synthetic opioid that has 75-200 times more potency and a much shorter half-life than morphine sulfate. It has fewer hypotensive effects than morphine and is safer in patients with hyperactive airway disease because of minimal or no associated histamine release. By itself, fentanyl citrate causes little cardiovascular compromise, although the addition of benzodiazepines or other sedatives may result in decreased cardiac output and blood pressure.
Fentanyl citrate is highly lipophilic and protein-bound. Prolonged exposure to it leads to accumulation of the drug in fat and delays the weaning process. Consider continuous infusion because of the medication's short half-life.
Alfentanil (Alfenta)
Ultra short acting analgesic that inhibits ascending pain pathways, increases pain threshold, and alters pain perception.
Anticholinergics, Respiratory
Class Summary
Anticholinergic agents can inhibit salivation and excessive secretions of the respiratory tract before surgery. These agents also control upper airway secretions.
Glycopyrrolate (Robinul, Cuvposa)
Glycopyrrolate acts in smooth muscle, the central nervous system (CNS), and secretory glands, where it blocks the action of ACh at parasympathetic sites.
Atropine (AtroPen)
Atropine is an antimuscarinic agent that inhibits the action of acetylcholine at parasympathetic sites in smooth muscle, the CNS and secretory glands.
Prokinetic Agents
Class Summary
Prokinetics are promotility agents, proposed for use with severe constipation-predominant symptoms.
Metoclopramide (Reglan, Metozolv)
Metoclopramide is characterized by remarkable stimulation of gastric emptying without stimulating gastric, pancreatic, or biliary secretions. Increases lower esophageal sphincter tone. Metoclopramide can be given two hours before the procedure.
Histamine H2 Antagonists
Class Summary
H2 blockers are reversible competitive blockers of histamine at H2 receptors, particularly those in the gastric parietal cells (where they inhibit acid secretion). The H2 antagonists are highly selective, they do not affect the H1 receptors, and they are not anticholinergic agents.
Histamine 2 (H2)–receptor antagonists should be administered preoperatively to prevent increase in gastric secretion during the procedure.
Ranitidine (Zantac)
This agent inhibits histamine stimulation of H2 receptors in gastric parietal cells, which reduces gastric acid secretion, gastric volume, and hydrogen ion concentrations. Histamine 2 (H2)–receptor antagonists should be administered preoperatively to prevent increase in gastric secretion during the procedure.
Famotidine (Pepcid)
Famotidine competitively inhibits histamine at the H2 receptors in gastric parietal cells, reducing gastric acid secretion, gastric volume, and hydrogen concentrations. Histamine 2 (H2)–receptor antagonists should be administered preoperatively to prevent increase in gastric secretion during the procedure.
Nizatidine (Axid, Axid AR)
This agent competitively inhibits histamine at the H2 receptor of the gastric parietal cells, resulting in reduced gastric acid secretion, gastric volume, and reduced hydrogen concentrations. Histamine 2 (H2)–receptor antagonists should be administered preoperatively to prevent increase in gastric secretion during the procedure.
Cimetidine (Tagamet HB 200)
This agent inhibits histamine at H2 receptors of gastric parietal cells, which results in reduced gastric acid secretion, gastric volume, and hydrogen concentrations. Histamine 2 (H2)–receptor antagonists should be administered preoperatively to prevent increase in gastric secretion during the procedure.
Alpha/Beta Adrenergic Agonists
Class Summary
These agents may be used to treat nasal congestion.
Ephedrine
Ephedrine releases tissue stores of norepinephrine, which when applied nasally produces local vasoconstriction resulting in nasal decongestion.
Local Anesthetics, Amides
Class Summary
Local anesthetics are used for local pain relief.
Lidocaine (Xylocaine with epinephrine)
Lidocaine 1-2% with or without epinephrine (1:100,000 or 1:200,000 concentration) is used. Lidocaine is an amide local anesthetic used in 1-2% concentration. The 1% preparation contains 10 mg of lidocaine for each 1 mL of solution; the 2% preparation contains 20 mg of lidocaine for each 1 mL of solution. Lidocaine inhibits depolarization of type C sensory neurons by blocking sodium channels. Epinephrine prolongs the duration of the anesthetic effects from lidocaine by causing vasoconstriction of the blood vessels surrounding the nerve axons.
Benzocaine, butamben, and tetracaine (Cetacaine)
These agents inhibit the conduction of nerve impulses by decreasing the neuronal membrane's permeability to sodium ions.
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The upper airway is divided into three regions depending on its major sensory innervations
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The anatomical relationship of the glossopharyngeal nerve
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Anatomy of the larynx showing the innervations from the branches of the vagus
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Nasal packing is done with cotton pledgets
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Superior laryngeal nerve block. The hyoid bone is held by the thumb and index fingers of the operator and displaced towards the side to be blocked
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Trans tracheal block. An intravenous cannula is inserted at the cricothyroid membrane
