Can you undergo anesthesia with heart palpitations?
Heart palpitations do not preclude a patient from receiving anesthesia. However, an individual with such a condition has to be investigated before the injection of anesthetics.
During anesthesia, it's common for heart rhythm changes to occur. One-third of the patients will become arrhythmic during intubation [1]. Also, during the sedation, the patient can develop dysrhythmia, but usually it does not require any treatment [2].
The probability of heart rate disturbance during the surgery depends on the type of drugs used to induce sleep [3]. Because of this fact, the drug schedule has to be adjusted in cases of heart palpitations.
What is anesthesia?
Anaesthesia is a pharmacological procedure that desensitizes the body of pain and sedates the patient to sleep. Its effects, such as the loss of feeling and awareness, are used in invasive procedures and surgeries. The group of medications used is known as anesthetics. They are administered in various ways, such as injection, inhalation, topical lotion, spray, eye drops, or skin patches [4].
The process of anesthesia involves several key steps. All of them are designed to ensure the safety and comfort of the patient throughout a surgical procedure.
The whole process starts with the preoperative evaluation, which is necessary to assess the patient’s health status. During the patient’s assessment, the medical history is taken and other needed laboratory findings are evaluated. This not only helps in the determination of the most suitable anesthesia technique but also allows for the identification of possible risks and complications [1].
After the patient passes the preoperative assessment, he can be admitted to the operation room. Here the first effective step occurs—the induction phase. During this phase, the patient is put into unconsciousness. Two ways of drug administration are used: intravenously or inhalation of gas [3, 2].
Once unconscious, the maintenance phase begins. To hold the patient in a stable sleep during the whole surgery, a continuous administration of anesthetic drugs is set. The anesthesiologist or nurse anesthetist closely monitors the patient's vital signs. Close monitoring allows medication adjustment according to the changes in the patient’s physiological state [5, 4].
When the surgeon is at the end of the operation, the reversal phase is introduced. Here, the anesthesia is gradually withdrawn, allowing the patient to regain consciousness. This phase also requires careful monitoring to ensure the patient's safety and comfort [1].
The last phase is the recovery phase. It occurs after the surgery is over and involves monitoring the patient as the effects of the anesthesia fade completely away. This includes assessing the patient's vital signs, pain levels, and overall physical condition [6].
What exact drugs are used in anaesthesia?
Anaesthesia involves the use of multiple drugs, typically four to six, to ensure loss of consciousness, analgesia, and neuromuscular blockade [11]. These drugs can be classified into several categories:
1. Narcotic Analgesics/Opioids: These include drugs like fentanyl, alfentanil, sufentanil, and remifentanil [12].
2. Induction Agents: These are drugs used to induce anaesthesia. Examples include propofol and etomidate [14], [13].
3. Muscle Relaxants/Neuromuscular Blocking Agents: These drugs are used to relax muscles during surgery. An example is cisatracurium [13].
4. Inhalation Anesthetics: These are gases or vapors inhaled by patients to induce or maintain general anesthesia. Examples include isoflurane [13].
5. Local Anesthetics: These are used to numb a specific area of the body. Examples include bupivacaine, ropivacaine, levobupivacaine, and lidocaine [16], [15].
6. Adjuvants: These are drugs used in combination with anesthetics to enhance their effect. Examples include opioids and alpha 2-sympathomimetics [17].
It's important to note that the exact drugs used can vary based on the patient's condition, the type of surgery, and the anesthesiologist's preference [11], [15].
What is the impact of anesthesia on the heart?
Anaesthesia works in neurons, so it can have a significant impact on the heart, which is also, to a certain degree, nerve-controlled. The effects vary depending on the type of anesthesia utilized and its duration, as well as on the patient's pre-existing heart conditions.
Spinal or epidural anesthesia (regional type) can affect cardiovascular function due to the blockade of the sympathetic nervous system [11]. This inhibition of the excitatory autonomic nervous system can have both beneficial and detrimental impacts on the heart. The effect depends on the underlying cardiac condition.
In patients with myocardial ischemia, epidural anesthesia decreases myocardial work and heart rate. Thanks to lower work, the myocardial oxygen demand lowers, which has a positive influence on decreasing cardiac stress. However, in patients with heart failure, where the heart does not fulfill the body’s blood demand, the situation is the opposite. The changes induced by anesthesia may worsen the hemodynamic condition, leading to low blood pressure and shock [11].
In general anesthesia, agents like halothane, sevoflurane, or propofol can also impact the heart. For instance, propofol can cause a mild impairment in left ventricular relaxation [12]. This lowers the volume, which can fill this lower chamber, decreasing the volume of the heart stroke. Halothane was found to decrease myocardial blood flow and oxygen consumption [13]. This situation is helpful during anesthesia. However, prolonged halothane anesthesia above 4.5 hours performed on dogs was found to increase myocardial oxygen uptake [14].
The proper choice of the drugs used is crucial. Especially in patients with heart diseases, proper control during anesthesia is important to avoid life-threatening situations.
How does anesthesia work on the body?
Anaesthesia works by inducing a reversible inhibition of neuronal activity in the body. It is achieved by the administration of anesthetics. Those pharmacological agents target specific central nervous system receptors. Once they bind to their brain receptors, they modulate remote brain areas and interfere with global neuronal networks, leading to a controlled and reversible loss of consciousness [7, 8].
There are three types of anesthesia. Local anesthesia works only locally, often on the skin, and it does not induce unconsciousness. Another type is regional anesthesia, which is administered to block the sensation of large regions. An example of this procedure is spinal or peripheral nerve anesthesia. The last is the general anesthesia performed before big operations.
General anesthesia is a balance of hypnosis, amnesia, analgesia, and immobility, including the inhibition of noxious autonomic reflexes. It is achieved by the administration of a combination of inhaled anesthetic gases and intravenous drugs [9, 3].
At the cellular level, anesthetics act through a variety of mechanisms. Local anesthetics, like lidocaine, inhibit sodium-specific ion channels in the neuronal cell membrane. The stoppage of sodium transport across the neuronal membrane interrupts the action potential and thus inhibits signal conduction. This process is reversible, but for the time of the inhibition, the nerves are not able to conduct the pain impulse to the brain [10].