Evaluating the Patient Before Anesthesia - Day of Surgery Premedication
Sedatives and Analgesics
The goal for administering sedatives and analgesics before surgery is to allay the patient's anxiety, to decrease pain during administration of regional anesthesia and preoperative line placement, and to facilitate smooth induction of anesthesia. It has been shown that the requirement for these drugs can be reduced by a thorough preoperative visit by an anesthesiologist. The dose of sedatives and analgesics must be reduced or withheld in a patient who is elderly, debilitated, or acutely intoxicated. The dose should also be decreased in a patient with upper airway obstruction, central apnea, neurologic deterioration, severe pulmonary disease, or valvular heart disease.
- Benzodiazepines. Benzodiazepines are highly effective in the treatment of anxiety. They also produce exceptional amnesia.
- Midazolam. Midazolam (Versed), 1 to 3 mg intravenously or intramuscularly, is a short-acting benzodiazepine that provides excellent anterograde amnesia and sedation. It should not be given to a sedated patient with an unsecured airway as it may cause significant respiratory depression, especially in combination with an opioid.
- Lorazepam. Lorazepam (Ativan), 1 to 2 mg orally or intravenously, may also be used but may cause more prolonged amnesia and postoperative sedation. It should not be given intramuscularly.
- Barbiturates. Barbiturates are rarely used for preoperative sedation; however, pentobarbital (Nembutal) is occasionally used by nonanesthesiologists for sedation during diagnostic procedures.
- Opioids. Opioids may be given preoperatively to a patient who has, or is anticipated to have, significant pain or to a patient who is opioid dependent. A patient coming from an inpatient ward may already be on morphine, hydromorphone, or meperidine and thus have a higher perioperative opioid requirement. The opioid-dependent patient should receive sufficient premedication to overcome tolerance and to prevent perioperative withdrawal. Intravenous fentanyl is appropriate for use immediately prior to induction as its effects are rapid and intense, but short lived.
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