Generality
Conscious anesthesia is a form of anesthesia that produces relaxation and controls the painful sensation, without inducing loss of consciousness.
Obtained with sedative, analgesic, hypnotic and / or anesthetic drugs, conscious anesthesia is used for minor surgery (eg reconstructive surgery operations) and mildly invasive diagnostic procedures (eg endoscopy or colonoscopy).
Conscious anesthesia is becoming an increasingly adopted practice, because it combines safety with efficacy, does not induce the loss of the senses at the time of its execution, produces a mild confusional state that quickly disappears, and does not necessarily require the presence of an anesthesiologist.
What is Conscious Anesthesia?
Conscious anesthesia, or conscious sedation, is a particular form of anesthesia which, in patients, induces relaxation and abolition of pain sensitivity, without causing loss of consciousness.
In other words, conscious anesthesia is anesthesia that settles and makes patients insensitive to pain, while keeping them completely awake and alert.
Conscious anesthesia is a decidedly lighter variant than general anesthesia, in which the patient loses consciousness and falls asleep.
Indications
Conscious anesthesia is used in minor surgery procedures and in mildly invasive diagnostic techniques, ie circumstances of limited duration which, in the absence of any anesthetic practice, would cause pain for which it would be excessive not to adopt any countermeasure, as would be excessive to resort to general anesthesia.
Conscious Anesthesia and Minor Surgery
Among the minor surgery procedures for which conscious anesthesia is an excellent resource, include:
- Minor foot operations;
- The minor operations at the level of the skin;
- The operations for the reduction of minor bone fractures;
- Plastic or reconstructive surgery (eg: myringoplasty and reconstruction of the ear lobe);
- The transvenous installation of a cardiac pacemaker;
- Operations to reduce joint dislocations;
- Ophthalmological surgery, such as the application of intraocular lenses or blepharoplasty;
- Dental surgery (eg reduction of a dental abscess) and reconstructive-dental (eg: dental implant).
Slightly Invasive Conscious and Diagnostic Anesthesia
In the diagnostic field, conscious sedation is a practice increasingly exploited on the occasion of:
- Endoscopy . It is the diagnostic technique that, through the use of an instrument equipped with a camera (endoscope), allows the esophagus, the stomach and the very first part of the intestine to be viewed from the inside.
- Colonoscopy . Similar to the instrumentation used for endoscopy, it is the diagnostic technique that allows us to study the various tracts of the large intestine (colon, sigma and rectum) from the inside.
- Bronchoscopy . Based on the use of an instrument very similar to that used for endoscopy and colonoscopy, it is the diagnostic procedure that allows the analysis from within of the airways of greater caliber (larynx, trachea and bronchi).
- Cystoscopy . It is the diagnostic procedure aimed at exploring from inside the walls of urethra and, above all, bladder. The tool for its implementation broadly follows that of endoscopy and other previously mentioned practices.
- Transesophageal echocardiogram . It is the ultrasound of the heart that involves the insertion in the esophagus of the ultrasound probe fundamental for this type of radiological examination.
Compared to the classic transthoracic echocardiogram (where there is an external use of the ultrasound probe), the transesophageal echocardiogram provides much more detailed images, but it is also more invasive.
- Angiography . It is the radiological diagnostic test (it uses X-rays), which allows to study morphology, course and any abnormalities of blood and lymphatic vessels.
- Breast biopsy . It is the diagnostic procedure that consists in the collection and in the laboratory analysis of a sample of cells belonging to the mammary gland. It is essential for the diagnosis of breast cancer.
Preparation
Before being able to receive conscious anesthesia - generally, a few days before - the patient must undergo some medical checks, to find out if there is any obstacle to the aforementioned practice; moreover - but, in this case, near the procedure that foresees the use of conscious sedation - it will have to respect some fundamental norms for the good outcome of the same conscious anesthesia and for its own safety.
Medical check: what do they consist of?
The medical checks carried out in anticipation of conscious anesthesia consist of:
- Blood test and urine test . They allow to assess the general state of health of the patient (presence of infections, renal function etc.).
- Physical examination . It is a general medical examination, during which the doctor evaluates, in the patient, parameters, such as arterial pressure, temperature, heart rate, etc.
- History . it is the investigation that allows to establish if the patient is taking drugs (of particular interest are the drugs that modify the coagulability of the blood); is allergic to some medicines that could be used for conscious sedation; has been subjected to other types of anesthesia in the past and, if so, which ones; suffers from some chronic or genetic disease; etc.
As a rule, the medical checks in question must take place a week before the alleged date of the operation under conscious anesthesia, so that there is plenty of time to: carefully evaluate the blood and urine samples; make temporary changes to any pharmacological assumptions; finally, in case of impediments to conscious anesthesia (eg allergy to a certain drug used to obtain the latter), discuss solutions.
What to do and what not to do just before Conscious Anesthesia
On the day the conscious sedation procedure takes place, the patient must:
- Be at full fast for at least 6-8 hours . This means that, for interventions under conscious anesthesia scheduled for the morning, the last meal granted is the dinner of the previous evening. The exception is water, which is "free" up to 2-3 hours before the practice of conscious anesthesia;
- Introduce yourself accompanied by a family member or close friend . The family member (or friend) is used to support the patient at the end of the procedure, just before returning home and during the return home. However slight, in fact, conscious sedation alters, in a totally temporary way, the reflexes and the ability to concentrate, which are needed to be independent and carry out activities such as driving.
How is it done?
Doctors obtain conscious anesthesia by administering a mix of sedative, analgesic, hypnotic and / or anesthetic agents, appropriately dosed.
The possible routes of drug administration for the implementation of conscious anesthesia are: the intravenous route (injection of drugs into a vein), the intramuscular route (injection of drugs into muscle tissue), the oral route (drug ingestion) and the inhalation (delivery of drugs through a special mask).
timing
To obtain conscious sedation - that is to benefit from its relaxing and anti-pain effects - a wait of 5-10 minutes at most is sufficient, except in particular cases.
Conscious anesthesia has a limited duration in time, a duration that is in any case sufficient for the execution of therapeutic and diagnostic procedures for which the anesthetic practice in question is indicated.
When does the wait for conscious anesthesia get longer?
If the route of administration is oral, the wait to observe the first effects of conscious anesthesia can vary from 30 to 60 minutes, depending on the drugs used.
Drugs for Conscious Anesthesia: the details
The drugs most used in the implementation of conscious anesthesia include:
- Propofol . It is an anesthetic / hypnotic.
- Ketamine . It is an analgesic.
- Midazolam . It is a short-term analgesic, with also anxiolytic effects;
- Fentanyl . It is an analgesic with mild sedative effects;
- Dexmedetomidine . It is a sedative / analgesic.
As already stated, to achieve conscious sedation it is necessary to appropriately combine two or more of the aforementioned drugs.
The choice of the drug combination is up to the doctor and it is not at all accidental, but it depends on the characteristics of the patient (age, weight, allergies to drugs etc.).
The combination of drugs most popular in obtaining conscious anesthesia is between a sedative (in particular, midazolam) and an analgesic (in particular, fentanyl).
What are the patient's feelings during Conscious Anesthesia?
Once the drugs for conscious anesthesia have taken action, it is very likely to see a reduction in respiratory rate and a slight drop in blood pressure .
However, these changes must not scare, because they are normal consequences of the drugs in use and because they are subject to continuous monitoring by a member of the medical staff (who constantly checks that the vital parameters of the patients do not vary too much).
During procedures under conscious anesthesia, the medical staff connects the patient to machinery and devices for measuring and monitoring blood pressure, blood oxygen levels, heart rate and respiratory rate.
The patient, therefore, finds himself in a security situation .
Who's running it?
Conscious anesthesia is a practice that can be performed either by the doctor who will take care of the therapeutic or diagnostic procedure, or by an anesthesiologist (ie a doctor who specializes in anesthesiology).
After the Procedure
At the end of the procedures performed under conscious anesthesia, it is customary for the patient to feel slightly sleepy and confused, have a slight headache and feel sick to his stomach .
All these sensations are fleeting and disappear in the hours following the anesthetic practice.
Normally, those who have received conscious anesthesia can return home 1-2 hours after the end of the procedure, which has seen the use of the anesthetic practice in question.
Before returning home
Prassi wants that, while waiting to return home, the patient subjected to conscious sedation is subjected to periodic monitoring (every 15 minutes) of blood oxygen levels and blood pressure.
At home
Once discharged, the patient returning from conscious anesthesia should:
- Eat in a healthy and balanced way to recover at its best;
- Stand at rest until the following day, when the forces will be completely restored;
- Avoid driving and engaging in other activities that require a certain concentration;
- Avoid drinking alcohol;
- If subjected to surgery, carefully follow the instructions of the attending physician.
Risks and Complications
Conscious anesthesia is a very safe procedure, where "very safe" means that it rarely gives rise to side effects or even more rarely to serious complications.
Side effects and complications: what are they?
When something in the practice of conscious anesthesia does not go as it should, the patient could develop:
- Respiratory depression;
- Hypoxia;
- hypercapnia;
- Urticaria and allergic reactions;
- Temporary paresthesia;
- Muscle weakness;
- Local vasoconstriction;
- Hypotension;
- Visual hallucinations;
- Heart rate changes.
The precise picture of possible side effects and possible complications depends on the drugs used for conscious sedation, in how many such medicines do not all present the same risks.
Contraindications
Conscious anesthesia does not present particular contraindications ; however, it is good to specify that, in people with an allergy to the drugs necessary for its implementation, specific anti-allergic countermeasures must be adopted.
Results
Conscious anesthesia is an increasingly widespread medical practice (obviously within the limits of its indications), because it has many advantages; indeed:
- Conscious anesthesia is much appreciated by patients, as these, to its implementation, remain conscious and, once the principals have vanished, they do not feel the same annoying sensations of a "stronger" anesthesia as general anesthesia;
- Conscious anesthesia combines safety with efficacy;
- Conscious anesthesia does not necessarily require the presence of an anesthesiologist.
