Before undergoing surgery, it is common for patients to feel anxious or nervous. To help alleviate this anxiety, medications known as preoperative sedatives are often administered prior to the procedure. Preoperative sedatives, also called pre-meds, serve the purpose of producing a calming effect so that the patient remains relaxed before and during the surgery. They can help reduce apprehension, fear, and restlessness that many individuals experience when facing an impending surgical operation. The use of preoperative sedatives provides a number of benefits, which will be discussed in detail throughout this article.
What are Preoperative Sedatives?
Preoperative sedatives belong to a class of medications called central nervous system depressants. This means they work by depressing or slowing down the activity of the brain and central nervous system, inducing feelings of relaxation and calm. There are several different types of sedatives that may be used before surgery, including:
Benzodiazepines
Benzodiazepines are one of the most common classes of pre-meds prescribed. They work by enhancing the effects of the neurotransmitter GABA in the brain which leads to sedation, hypnosis, anxiety relief, amnesia, and muscle relaxation. Some examples of benzodiazepine drugs used before surgery include:
- Midazolam (Versed)
- Diazepam (Valium)
- Alprazolam (Xanax)
- Lorazepam (Ativan)
Barbiturates
Barbiturates are an older class of sedative medications. They are not used as commonly today as benzodiazepines but may still be prescribed as pre-meds in some cases. Examples of barbiturates used preoperatively include:
- Pentobarbital (Nembutal)
- Secobarbital (Seconal)
- Thiopental (Pentothal)
Propofol
Propofol induces sedation, hypnosis, and amnesia. It starts working very quickly and also wears off rapidly after administration is stopped. This makes it a popular choice for pre-med sedation before short surgical procedures.
Ketamine
In lower doses, ketamine provides pain relief and sedation without compromising respiration or blood pressure. It may be preferred over other sedatives in certain situations, like for patients who have trouble breathing.
Dexmedetomidine
Dexmedetomidine provides sedation and pain relief without causing significant respiratory depression. It has anxiolytic and analgesic effects as well, making it useful for pre-med sedation.
Opioids
Opioid pain medications like morphine, fentanyl, or hydromorphone are sometimes administered with other pre-meds for their synergistic sedative and analgesic effects. They can help enhance the calming and pain-relieving actions of medications like benzodiazepines.
Uses and Benefits of Preoperative Sedation
There are a number of reasons why sedatives are commonly prescribed prior to surgical procedures. Some of the main uses and benefits of preoperative sedative medications include:
- Reducing anxiety and fear – Sedatives help patients feel relaxed and less anxious before surgery.
- Inducing amnesia – Some sedatives cause short-term memory loss so patients don’t remember being scared or in pain.
- Improving patient compliance – Calmer patients are more likely to follow instructions from doctors and nurses.
- Facilitating induction of general anesthesia – Sedatives prep the body for the anesthetic drugs used during surgery.
- Providing pain relief – Pre-meds like opioids have analgesic effects to prevent pre-surgery discomfort.
- Allowing for lower doses of anesthetics – Sedation beforehand means less anesthesia required during the procedure.
- Preventing side effects from anesthesia – Lower anesthetic doses mean fewer adverse effects like nausea.
- Aiding with recovery – Sedation before surgery promotes relaxation and sleep after the operation.
By reducing anxiety and providing a smoother transition through the surgical experience, preoperative sedatives can benefit both the patients undergoing surgery as well as the medical staff caring for them.
Guidelines for Administering Preoperative Sedatives
While preoperative sedatives provide many advantages, they must be prescribed and administered appropriately to ensure proper dosing and minimize risks. Some general guidelines surround their use include:
- Tailoring the regimen to each patient’s health status and needs.
- Choosing the optimal medication or combination of medications.
- Adjusting doses based on the patient’s age, weight, medical conditions, and prior response to sedatives.
- Administering at the right time – typically 30-60 minutes before surgery.
- Monitoring vital signs closely after giving pre-meds.
- Having emergency equipment and medications available in case of oversedation.
- Performing cognitive and reflex testing to gauge the level of sedation.
- Using the lowest effective doses to avoid excessive sedation.
Following procedure protocols and individualizing treatment helps maximize the preoperative sedative benefits while minimizing adverse reactions.
Most Commonly Prescribed Preoperative Sedatives
The types of sedative medications used preoperatively can vary depending on factors like the patient’s health status, type of surgery, physician preferences, and hospital protocols. However, there are a few drugs that are used very frequently as pre-meds:
| Medication | Drug Class | Common Brand Names |
|---|---|---|
| Midazolam | Benzodiazepine | Versed |
| Fentanyl | Opioid | Sublimaze, Actiq |
| Propofol | Hypnotic | Diprivan |
| Dexmedetomidine | Sedative | Precedex |
| Ketamine | Dissociative anesthetic | Ketalar |
These medications are commonly used because they reliably provide sedation, amnesia, and anxiolysis when given in proper doses. They are also relatively fast acting and short duration, which is advantageous for procedures.
Specific Medications
While many different preoperative sedatives may be administered, there are a few specific drugs that are especially common and effective for pre-medication:
Midazolam
Midazolam is a benzodiazepine that is one of the most frequently prescribed pre-meds. Trade names include Versed and Dormicum. Midazolam has rapid onset of action and short duration, making it ideal for use before short surgery. It provides sedation, amnesia, and anxiety relief. Midazolam can be given intravenously or intramuscularly. Common dosing is around 2-5 mg in adults. It is metabolized quickly so effects wear off within 1-2 hours.
Fentanyl
Fentanyl is a fast acting synthetic opioid analgesic. It is given via intravenous injection as a pre-medication, often together with a benzodiazepine like midazolam. Fentanyl provides pain relief and enhances the sedative effects of other drugs. Doses for pre-med use are typically 25-100 mcg for adults. Effects begin within 5 minutes and last 30-60 minutes. Fentanyl helps improve preoperative comfort and perioperative hemodynamic stability.
Propofol
Propofol induces sedation rapidly when administered intravenously, usually taking effect within 40 seconds. It has short duration with the effects wearing off quickly after the infusion is stopped. Propofol decreases anxiety and provides amnesia and pain relief as well. It can depress breathing at higher doses so lower doses are used for pre-med sedation. Typical dosing is around 10-40 mg in adults. The fast onset and offset makes it ideal for short surgical cases.
Dexmedetomidine
Dexmedetomidine provides sedation and anxiety relief without significantly depressing the respiratory system, making it useful in some higher risk patients. It offers analgesic properties too. Dexmedetomidine is given intravenously with doses around 0.2-1 mcg/kg over 10-15 minutes. It has a quick onset and the sedative effects dissipate within 15 minutes. Dexmedetomidine helps maintain hemodynamic stability as well.
Ketamine
Ketamine is a unique drug that provides analgesia, sedation, and amnesia. It causes a dissociative, trance-like state while maintaining respiratory drive. Ketamine is given intravenously or intramuscularly, with doses around 0.5-1 mg/kg typically used as a premed. It takes effect rapidly and lasts around 10-15 minutes. Ketamine is useful for sedation and pain control in higher risk patients.
Preoperative Sedation in Pediatric Patients
Sedative pre-medication is common for pediatric patients undergoing surgery as well. Anxiety and agitation are frequent in children preoperatively. Appropriate sedative techniques provide comfort, facilitate separation from parents, and aid with induction of anesthesia. Some considerations for preoperative sedative use in pediatric patients include:
- Younger children often require higher weight-based drug doses compared to adults.
- Oral routes are preferred when possible to avoid injections.
- Medications like midazolam are commonly used.
- Ketamine is advantageous for sedation and pain control in pediatric cases.
- Drug combinations synergistically enhance sedation while minimizing adverse effects.
- Doses should be titrated to each child’s response and needs.
- Family members can be present until children become sedated.
Sedating anxious children before surgery improves the preoperative experience for the patients and medical staff alike. Appropriately prescribed and monitored pre-meds provide pediatric patients with comfort, amnesia, and anxiolysis before their procedures.
Intravenous Versus Oral Administration
Preoperative sedatives can be given through various routes of administration. Two of the most common include:
Intravenous
Many pre-meds like midazolam, propofol, fentanyl, and dexmedetomidine are formulated for intravenous injection. This allows rapid absorption directly into the bloodstream. IV administration provides faster onset of drug effects compared to oral ingestion. It also allows more precise dosing and titration to reach the desired level of sedation. Intravenous pre-meds are preferred when a quick, predictable response is needed right before surgery.
Oral
Some sedatives like benzodiazepines are available in formats like tablets that can be taken orally. Oral sedative pre-medication has a slower onset compared to IV drugs. However, oral preoperative sedatives can be given further in advance of surgery. For example, a sedative tablet could be administered the night before or 1-2 hours before an operation. This is convenient for outpatient cases. Oral pre-meds are also useful for pediatric patients to avoid frightening injections before surgery.
The route of preoperative sedative administration depends on factors like the surgery timing, desired speed of onset, patient preferences, and medication formulations available. IV injections provide rapid effects, while oral pre-meds allow more flexibility with dosing schedules.
Preoperative Sedation in Outpatient Surgery
Many surgeries today are performed on an outpatient basis, with patients going home the same day as their procedure. Preoperative anxiolysis and sedation continue to play an important role for many outpatient surgeries. However, some special considerations apply in these ambulatory cases:
- Short-acting medications like midazolam are preferred drugs.
- Lower doses minimize side effects and aid discharge recovery.
- Oral sedative pre-medication allows for administration before arrival.
- Patients need longer recovery times before discharge.
- Discharge instructions must include warnings about sedative effects.
- Patients should not drive or perform complex tasks after receiving pre-meds.
By selecting optimal medications, doses, and routes of administration, preoperative sedation can be provided safely and effectively even for surgeries involving same-day discharge. This improves ambulatory surgery experiences for appropriately selected patients.
Side Effects and Risks
While preoperative sedatives have many advantages, they can also carry risks of potential side effects and adverse reactions:
- Excessive sedation or loss of consciousness
- Respiratory depression and airway obstruction
- Hypotension and low blood pressure
- Paradoxical reactions like agitation or delirium
- Nausea and vomiting
- Headache
- Prolonged drowsiness after surgery
- Confusion and impaired cognition
- Increased risk of falls
To help mitigate these risks:
- Appropriate doses should be used for each patient’s health status.
- Patients require close monitoring of vital signs and sedation levels.
- Preoperative testing can identify patients with increased risk for complications.
- Sedatives should be avoided in some high-risk groups like those with severe lung disease or sleep apnea.
- Rescue agents and equipment must be readily available to intervene for adverse reactions like severe respiratory depression.
While not completely without risks, preoperative sedation provides significant benefits that usually outweigh the potential downsides when administered judiciously.
Conclusion
Preoperative sedation involves administering medications like benzodiazepines and propofol before surgical procedures. This provides anxiety relief, amnesia, and comfort for patients facing operations. Pre-med sedation facilitates anesthesia and improves the perioperative experience. Intravenous drugs like midazolam and fentanyl are most commonly used due to their rapid onset. Oral sedatives may be preferred in some outpatient settings. While beneficial, pre-meds can also cause side effects so proper dosing and monitoring are essential. Overall, judicious sedative premedication remains an integral part of quality, patient-centered surgical care.