Local anesthetics block the conduction of pain impulses, affecting motor and sensory nerves. The nurse should be aware of signs of toxicity, including tachypnea, tachycardia or bradycardia, tinnitus, drowsiness, metallic taste, numbness around the mouth, paresthesias, tremors, seizures, and coma.
Regional anesthesia uses local anesthetics cause a temporary loss of sensation in a particular portion of the body. Types of regional anesthesia include a spinal, epidural, nerve block, and Bier block.
Spinal anesthesia is usually used for surgery on the lower abdomen, groin area, perineum, or lower extremities. The anesthetic agent is injected into the cerebrospinal fluid (CSF) in the subarachnoid space.
Risks include hypotension, inadvertent high level of anesthesia that causes respiratory arrest and complete paralysis, neurologic complications, spinal headache, and infection.
Epidural anesthesia can be used for abdominal, genitourinary, and lower extremity procedures. It involves injecting the anesthetic agent into the epidural space, which is outside the CSF.
Compared to a spinal, an epidural requires higher doses of anesthetic, has a slower onset and is not dependent on the patient’s position for the level of anesthesia. The provider is able to titrate the dose throughout the procedure.
Risks include hypotension, headache, respiratory depression, and neurologic complications, but are not as common as with spinal anesthesia.
Other risks include infection and a higher potential for failure than with a spinal. Another regional anesthesia is the nerve block, in which the local anesthetic is injected around a peripheral nerve.
A Bier block is an intravenous regional anesthetic, injected into the veins of an arm or leg while using a tourniquet to prevent the anesthetic from entering the systemic circulation.
This technique must be limited to two hours or less, or tissue damage can occur from the use of the tourniquet.
Let’s look at the levels of sedation… Minimal sedation uses sedatives and anxiolytics that allow the patient to remain responsive and breathe independently.
Moderate sedation and analgesia (also known as ‘conscious sedation’), is a drug-induced depression of consciousness in which the patient is able to respond purposefully to verbal commands and touch, maintain adequate spontaneous ventilation, and won’t remember anything from the procedure.
Deep sedation and analgesia is a drug-induced depression of consciousness during which patients cannot be easily aroused but respond purposefully following repeated or painful stimulation.
Independent breathing may be impaired. General anesthesia is the depression of the central nervous system by the administration of drugs or inhalation agents. Patients are not arousable, even by painful stimuli, and respiratory and cardiovascular functions are often impaired.
There are three phases of general anesthesia, including induction, maintenance, and emergence.
The intraoperative nurse is involved in the induction of emergence from general anesthesia of the patient. Induction begins with the administration of the anesthetic agents.
Endotracheal intubation is performed during this phase, while the nurse is at the patient’s bedside to provide support and to assist the anesthesiologist.
The nurse may be asked to provide cricoid pressure before intubation, which prevents aspiration and regurgitation of stomach contents by obstructing the esophagus.
Once the patient is ready for positioning, skin prep, or incision, the patient is now in the maintenance phase of anesthesia during which the anesthesiologist maintains the appropriate levels of anesthesia for the length of the procedure. When the anesthesiologist begins to waken the patient, the emergency period has begun.
The patient is extubated and the nurse needs to be available to assist the provider as needed with patient safety and comfort, since the patient may experience vomiting, shivering, or restlessness.
The intraoperative nurse also needs to beware of the thermoregulatory response of the patient during surgery. General anesthetics, muscle relaxants, and opioids can all cause a decrease in body temperature.
In the OR, the patient also loses core body heat due to the cool environment; infusion of IV fluids; cool skin prep solutions; cold, dry anesthetic gases; and escape through the surgical incision.
The intraoperative nurse needs to take measures to keep the patient warm – covering exposed areas as much as possible with warmed blankets and using warmed IV solutions will help prevent hypothermia.
Occurring less often than hypothermia, intraoperative hyperthermia, or an increase in body temperature of 3.6 degrees F per hour.
It may be caused by sepsis, infection, or less commonly, malignant hyperthermia, in which the patient’s temperature may rise1.8 to 3.6 degrees F every 5 minutes and may exceed 109.4 degrees F.
It is a potentially fatal complication of general anesthesia, when there is a genetic defect in the muscle cell membrane, making the patient more susceptible.
Along with the rising temperature, symptoms include muscle rigidity, respiratory and metabolic acidosis, and a fast heart rate.
Treatment includes immediately ceasing the causative agent, hyperventilating with 100% oxygen, cooling with ice packs or cooling blankets, restoring acid-base balance, treating hyperkalemia, and giving IV dantrolene (the antidote).
Cooling measures should be stopped when the patient’s temperature reaches 100.4 degrees F.
Caring for the patient in the intraoperative environment involves many technical activities; however, the nurse is also responsible for meeting the patient’s psychosocial needs.
The operative phrase is often short, and the patient may be sedated or unconscious most of the time.
However, the intraoperative nurse has a significant impact on the patient’s response to the surgical experience.
Surgery is a stressful experience for anyone, and providing explanations of procedures and events helps promote a sense of security and effective coping for the patient.