Medical teams use a variety of different types of anesthesia depending on the procedure and patient. Although the goal is always the same, to keep a patient safe, comfortable, and pain-free, the best option could be one of the following three types of anesthesia.
General anesthesia renders the patient unconscious, and the vital functions of the body including respiration and hemodynamic support will require the assistance of a well trained anesthesiologist. Anesthesiologists use general anesthesia most during major procedures such as heart surgeries and major abdominal operations. These surgeries would not be possible without general anesthesia to manage the patient’s pain. The speed of the surgeon was far more significant back in the days when the only thing available was whiskey and “biting the bullet”! Today, General anesthesia can be administered via face mask, endotracheal tube or other airway devices such as a laryngeal mask airway (LMA) using gas anesthetics in the form of methylated ethers commonly used or through the use of intravenous agents such as propofol.
Unlike propofol which has antiemetic properties, exposure to volatile gas anesthetics is a risk factor for postoperative nausea and vomiting (PONV). When a patient wakes up, they may suffer from nausea, vomiting, or chills. If a patient has a history of motion sickness or a prior history of PONV, it’s important to tell the anesthesiologist so that they can treat patients accordingly with additional medications to help prevent these symptoms.
Sedation is classified into 3 levels. Mild (Anxiolysis), Moderate (Conscious Sedation) and Deep sedation. This anesthetic choice is used for minor surgeries or procedures when general anesthesia isn’t necessary. When a patient receives sedation, they are in a sedated/relaxed state and depending on the varying level of sedation may or may not be conscious or able to follow verbal commands or have a purposeful response to a painful stimulus. In most cases the patient will not remember the procedure after “waking up”. Sedation is normally used for procedures like biopsies, cataract surgery and colonoscopies.
During Minimal Sedation, or Anxiolysis, patients will be able to respond to verbal commands. Their cognitive function and physical coordination will be decreased, but the sedation will not hinder their airway reflexes, and ventilatory and cardiovascular functions.
Moderate Sedation/Analgesia, or Conscious Sedation, is a drug-induced depression of consciousness. The patient will still be able to respond to verbal commands, but may also require minimal tactile stimulation to do so. The patient normally retains their cardiovascular function, and does not usually require any airway interventions.
When a patient receives Deep Sedation/Analgesia, they enter a drug-induced loss of consciousness and cannot be easily aroused. They may not be able to independently maintain ventilatory function, and may need assistance in maintaining a patent airway. Their cardiovascular function, however, is usually unaffected and does not require hemodynamic support.
Regional anesthesia includes a variety of different neuraxial blocks, such as a femoral nerve block or popliteal fossa block for lower extremity surgery or interscalene, supraclavicular and axillary block for upper extremity surgery. A transversus abdominal plane (TAP) block is commonly used for abdominal surgery or c-sections. These nerve blocks utilize ultrasound guidance and nerve stimulators to pinpoint the target nerve at which point a moderate volume of local anesthetic is injected into the area resulting in a “numbing” effect in the distribution of the nerve involved, usually blocking both sensation and motor function. This type of anesthesia is normally used during procedures that require more than a simple local anesthetic and can be used as the sole anesthetic in combination with sedation, but in many cases nerve blocks are used in conjunction with general anesthesia for postoperative pain control.
Additionally, regional anesthesia includes epidural and spinal anesthesia. In the case of epidurals, a catheter is placed and medication is infused at a constant rate and can be adjusted accordingly over time. They are most often used during labor and delivery and can be left in place for days as needed. In this way, the pain is blocked but the mother is still awake enough to follow directions and push when it’s time for the delivery. Spinal blocks typically involve a single shot directly into the cerebral spinal fluid and usually last 1 to 3 hours. Spinal anesthesia delivers a more dense and reliable block than an epidural. Spinals are most often used during cesarean deliveries (c-sections). Regional anesthesia has the additional benefit of avoiding many of the risks and side effects of general anesthesia..
Patients should be aware of the different types of anesthesia and the risks and benefits of each in order to make an informed decision about what option is best for their specific surgery. The anesthesiologist can help choose the right option depending on the surgeon’s and patient’s preferences as well as the type of surgery/procedure.