Medication Summary
The goals of pharmacotherapy are to reduce morbidity and prevent complications.
Anesthetics, Topical
Class Summary
Local anesthetics are used to facilitate the procedure.
Lidocaine topical (Topicaine, Lidocin, Glydo)
Decreases permeability to sodium ions in neuronal membranes. This results in the inhibition of depolarization, blocking the transmission of nerve impulses.
Analgesics
Class Summary
Induction of anesthesia is accomplished by using opioids. Pain control is essential to quality patient care. Analgesics ensure patient comfort, promote pulmonary toilet, and have sedating properties that are beneficial for patients who experience pain.
Morphine (Duramorph, Infumorph)
Morphine sulfate is the DOC for analgesia owing to its reliable and predictable effects, safety profile, and ease of reversibility with naloxone.
Anxiolytics, Benzodiazepines
Class Summary
Indicated for patients that may experience significant anxiety before a surgery.
Lorazepam (Ativan)
Lorazepam is a sedative-hypnotic of the benzodiazepine class that has a rapid onset of effect and a relatively long half-life. By increasing the action of gamma-aminobutyric acid (GABA), a major inhibitory neurotransmitter, it may depress all levels of the central nervous system (CNS), including the limbic system and reticular formations. Lorazepam is excellent for patients who need to be sedated for longer than 24 hours.
Midazolam
Midazolam is a sedative-hypnotic of the benzodiazepine class that provides initial sedation as well as amnesia.
Diazepam (Diastat, Diastat AcuDial, Valium)
Diazepam modulates the postsynaptic effects of gamma-aminobutric acid–A (GABA-A) transmission, resulting in an increase in presynaptic inhibition. It appears to act on part of the limbic system, the thalamus, and hypothalamus, to induce a calming effect. It also has been found to be an effective adjunct for the relief of skeletal muscle spasm caused by upper motor neuron disorders.
Diazepam rapidly distributes to other body fat stores. Twenty minutes after initial IV infusion, the serum concentration drops to 20% of maximum plasma concentration (Cmax).
Individualize dosage and increase cautiously to avoid adverse effects
General anesthetics
Class Summary
These agents stabilize the neuronal membrane so the neuron is less permeable to ions. This prevents the initiation and transmission of nerve impulses, thereby producing the local anesthetic effects.
Fentanyl (Sublimaze)
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.
The parenteral form is the drug of choice for conscious-sedation analgesia. Fentanyl citrate is ideal for analgesic action of short duration during anesthesia and the immediate postoperative period. It is an excellent choice for pain management and sedation with short duration (30-60min) and is easy to titrate. The drug’s effects are easily and quickly reversed by naloxone.
Propofol (Diprivan)
Propofol is a phenolic compound unrelated to other types of anticonvulsants. It has general anesthetic properties when administered intravenously. Propofol IV produces rapid hypnosis, usually within 40 seconds. The effects are reversed within 30 minutes, following the discontinuation of infusion. Propofol has also been shown to have anticonvulsant properties.
Ketamine (Ketalar)
Ketamine acts on the cortex and limbic system, decreasing muscle spasms.
Etomidate (Amidate)
Amidate is a nonbarbiturate imidazole compound with sedative properties. It is short-acting and has a rapid onset of action; the duration of action is dose dependent (15-30 minutes). Its most useful feature as an induction agent is that it produces deep sedation while causing minimal cardiovascular effects.
The major application of amidate is induction for endotracheal intubation, particularly in patients with, or at risk for, hemodynamic compromise. Amidate has been shown to depress adrenal cortical function; however, this effect is not significant clinically during short-term administration. Since the drug is mixed in propylene glycol, continuous infusion not recommended.
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Disposable anoscope with integrated light source. Image courtesy of Welch Allyn.
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Plastic disposable anoscope with obturator in place.
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Plastic disposable anoscope with obturator removed.
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Standard lubricating jelly.
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Stainless steel anoscope. Image courtesy of Welch Allyn.
