Overview of Procedural Sedation
Procedural sedation, previously referred to as ‘conscious sedation,’ is a set of techniques and medications used to help a person bear painful or unpleasant procedures. It also aims to prevent any unwanted memories after undergoing these procedures. Along with reducing pain perception, procedural sedation also makes the procedure more likely to be successful, cuts down the procedure time, and enhances safety for the patient and the medical personnel. A variety of medicines, psychological tactics, and physical actions are used to achieve this effect.
According to the American College of Emergency Physicians (ACEP), procedural sedation, often combined with analgesics (painkillers), aims to induce a state that lets the patient tolerate uncomfortable procedures while maintaining heart and lung function. It seeks to produce a reduced level of awareness that allows the patient to independently manage oxygenation (breathing in enough oxygen) and airway control.
In different situations, the implementation of procedural sedation shows considerable variability, is practiced with different skill levels, and has caused controversy in the past. This practice is not limited to anesthesiologists; it is also frequently employed by emergency clinicians, intensive care specialists, and several nursing specialists. Therefore, this information aims at laying out a standard method of practice, addressing controversies, and providing additional resources from external sources to enrich your understanding.
Different guidelines have been proposed for practicing procedural sedation, with variations between them. For instance, unlike the guidelines suggested by the American Society of Anesthesiologists (ASA), guidelines by the American Society for Gastrointestinal Endoscopy (ASGE) do not consider the use of capnography monitoring (a technique that monitors the concentration of carbon dioxide in exhaled air) useful during procedural sedation.
It’s important to understand that sedation (helping the patient remain still), analgesia (relieving pain), and dissociation (creating a feeling of physical and mental separation) are different concepts. Procedural sedation combines these concepts based on the patient’s anxiety level and pain intensity to provide optimal sedation and analgesia. This technique is most commonly used for noninvasive or minimally invasive procedures, mostly conducted outside of an operating room, such as in emergency departments, dentistry, radiology, and gastrointestinal endoscopy.
Different tools have been developed to measure sedation level, both in the operating room and in other settings. The Ramsay scale, for example, describes six categories from anxious, agitated, or restless, to unresponsive to painful stimuli. It is widely used but doesn’t distinguish effectively between intentional and unintentional responses. Several tools have been modified to better align with guidelines, such as the Observer’s Assessment of Alertness/Sedation (OAA/S) scale, which is easy to use but not very effective in differentiating deep levels of sedation.
In practice, the most commonly acknowledged terms for sedation depth are minimal (also known as anxiolysis), moderate (also known as conscious sedation), deep, and dissociative. Essentially, with minimal sedation, the patient remains awake but calm and responsive. With moderate sedation, the patient’s consciousness is reduced, but they can respond to verbal requests or touch and breathe normally. Deep sedation renders the patient mostly unresponsive, and they may require breathing support. Dissociative sedation creates a sort of trance where patients remain conscious but unaware of pain and will not remember the procedure afterwards, though they can still follow commands.
Furthermore, it is generally understood that due to variations in people’s sensitivity to medications and pre-existing health conditions, patients might end up being more sedated than planned. Therefore, the medical professional needs to be prepared for this possibility.
Anatomy and Physiology of Procedural Sedation
One of the most serious complications of certain health conditions is respiratory failure, which can be caused by a blocked airway or difficulties with breathing. Therefore, it’s incredibly important for your doctor to know specifically about the structure of your airways, any unique features they might have, and if you’ve had any problems with them in the past. One tool that doctors often use to check this is the Mallampati score.
In order to figure out if there might be any challenges with helping you breathe (also known as ventilation), your doctor needs to thoroughly check certain characteristics. These might include unusual or uneven facial features; a beard; being very underweight, which can cause your cheeks to sink in and teeth to fall out; facial injuries like cuts through the cheek or broken bones; limited neck movement and a mouth that opens less than about two inches, which can make it difficult to access the airways; and being overweight, which can pose a challenge to ventilation even if none of the other features are present.
Why do People Need Procedural Sedation
Procedural sedation (PS) and analgesia (PSA) are performed when a patient needs a procedure that might cause a lot of discomfort. The level of sedation needed depends on how much pain the patient will likely experience and whether they need to stay still during the surgery. For instance, a bone treatment that needs joint reduction and muscle relaxation will require a deeper level of sedation than a less painful procedure. Doctors also take into account the patient’s vital signs, such as breathing and blood pressure measurements. For instance, a patient who could be seriously affected by a pause in breathing or a drop in blood pressure might be better off with a special sedative technique rather than moderate to deep sedation.
Also, doctors review the patient’s health history for chronic diseases (like heart or lung diseases) and their stability, drug history, and allergies before recommending for a sedation. This is to assess the risk concerning the proposed sedation and the procedure.
One popular system doctors use to assess a patient’s health before a procedure or sedation is the ASA Physical Status scoring:
* ASA Class 1: A healthy patient with no diagnosed illnesses or medical conditions. This doesn’t include very young or very old patients but generally means they are in good health and can tolerate normal physical activity.
* ASA Class 2: Patients with a minor chronic condition like well-controlled hypertension (high blood pressure) or diabetes, smoking without chronic obstructive pulmonary disease (COPD), minor obesity, pregnancy.
* ASA Class 3: Patients with a serious but controlled disease, like congestive heart failure (CHF or a weak heart), stable angina (chest pain), prior heart attack, poorly controlled hypertension, severe obesity, chronic kidney disease, a lung disease with occasional symptoms.
* ASA Class 4: Patients with uncontrolled or end-stage diseases that are life-threatening. Such conditions may include unstable angina, symptomatic COPD, symptomatic CHF, liver and kidney failure.
* ASA Class 5: Patients who aren’t expected to live without the operation, generally requiring immediate surgery to survive. These might include multi-organ failure, infection-induced body shock with unstable blood pressure, hypothermia, poorly controlled blood clotting disorder.
* ASA Class 6: A patient declared brain-dead whose organs are being harvested for donor purposes.
Additionally, the letter ‘E’ added to any ASA physical class means there’s an emergency. An emergency procedure is one where delaying the treatment could lead to a significant risk to the patient’s life or a specific body part.
When a Person Should Avoid Procedural Sedation
PSA, or procedural sedation and analgesia, might not be suitable in some situations for various reasons:
– If the healthcare professional conducting the sedation isn’t trained enough to handle emergencies like securing an unstable airway (which means keeping the airway open with tools from intubation to cricothyrotomy), PSA cannot be used.
– PSA shouldn’t be used if required monitoring and resuscitation tools are not at hand.
– If the patient requires a longer or more complex surgical procedure, they might be better off with general anesthesia in a surgical room.
– If a patient has a high ASA risk score, indicating they are at risk during anesthesia, the services of an experienced anesthetist might be safer than PSA. Particularly, use of PSA is not recommended for patients who are classified as ASA class II or IV, and are unstable (unless they need immediate intervention like ventricular tachycardia conversion).
– Patients with allergies or sensitivities to medications used in PSA should not receive PSA.
Patients at a high risk of aspiration, such as those under the influence of alcohol, should also avoid PSA. Regarding how long patients should fast before undergoing procedural sedation, you can refer to the same guidelines used for general anesthesia. These suggest 2 hours for clear fluids (excluding alcohol) and 6 hours for solid foods. Infants can be given breast milk up to 4 hours before the procedure. However, if a patient ate fried or fatty foods or meat, they might need to fast for 8 or more hours.
Equipment used for Procedural Sedation
Before starting a procedure that requires anesthesia, such as Procedural Sedation and Analgesia (PSA), the medical team needs to have certain pieces of equipment ready to use. This equipment includes:
* A functioning intravenous line (IV) through which fluids and medications can be delivered into the body.
* The necessary medications and equipment in case of a cardiac emergency, or heart-related problem.
* Different types of equipment to deliver oxygen to the patient, ranging from a simple nasal cannula (a small tube that fits into the nostrils) to high-flow oxygen masks.
* A suction device used to clear the airway.
* Various airway equipment, such as a bag valve mask (used to assist breathing), a laryngeal mask airway (inserted into the throat to keep the airway open), a bougie (a thin, flexible surgical instrument), devices for performing laryngoscopy (examining the larynx or voice box), and endotracheal tubes (inserted into the windpipe to assist breathing).
Sometimes during these procedures, harmful effects might occur due to the use of certain medications. For this, doctors keep reversal drugs on hand which can end the effects of medications like opioids and benzodiazepines. Naloxone and flumazenil are examples of these drugs and can cancel out the effects of fentanyl (a type of opioid) and midazolam (a type of benzodiazepine), respectively. However, doctors take caution with the use of flumazenil, as it can cause severe seizures, particularly in patients with substance abuse problems or a history of seizure disorders.
Finally, doctors also need to have different monitoring equipment to keep track of the patient’s heart, blood pressure, blood oxygen level (measured using a pulse oximeter), breathing rate, and the amount of carbon dioxide exhaled (measured using an EtCO2 monitor).
Who is needed to perform Procedural Sedation?
In a perfect world, two medical professionals would handle your treatment. One would focus on the main procedure you’re there for, while the other would handle things like making sure you’re relaxed, keeping an eye on your health, and making sure everything goes smoothly. Sadly, there are quite a few situations where having two professionals isn’t possible, especially when the treatment was unplanned. This is more often the case in places that are remote or don’t have a lot of resources. If there’s only one professional available to handle your treatment, they’ll be ready to stop the procedure and take care of you if you should need it.
The healthcare professionals who are a part of PSA (a quick, safe treatment that requires you to be asleep) have to be experienced in a few areas:
- Selecting the right patient for the treatment
- Having advanced skills in managing your airway (a must-have if they’re going to be doing these procedures)
- Knowing how to handle and give the right medication
- Keeping track of your health during the treatment
- Tackling any complications that might come up
Preparing for Procedural Sedation
Before carrying out a procedure requiring sedation (PSA), careful planning should be made. Ideally, these plans should be practiced in a simulated setting before the actual procedure.
When preparing, it helps to adhere to standard steps or procedures – this can act as a guide or checklist. This checklist can be something like the one offered by the World Health Organization. Below are some items you’d typically find on such a checklist:
- Check the patient’s identity, the procedure they will undergo, and ensure they’ve given informed consent.
- Clearly map out the area on the patient’s body where the procedure will take place or mark the side of the body if necessary.
- Have necessary medications ready – this includes drugs that can reverse the effects of other drugs if needed. An example of this is naloxone, which can be used to reverse the effects of opioids. Some may lack reversal drugs but can be managed with “agents/adjuncts” like bag-mask in case propofol is used.
- Ensure all monitoring devices like heart rate monitors (EKG), oxygen saturation monitors (SaO2), and carbon dioxide output monitors (EtCO2) are working, and be aware of any possible misinformation they may present (For example, the SaO2 monitor can drop during automatic blood pressure checks due to temporary interruptions in blood flow). High levels of EtCO2 are preferred because they indicate that the patient is not breathing deeply enough sooner than SaO2 can.
- Check for any potential issues or unusual features with the patient’s airway (using simulation scores like Mallimpati).
If the patient wears contact lenses, these need to be removed before the procedure, especially if nitrous oxide will be used. Everyone on the medical team needs to know and understand their roles – having these key images on display can help with this.
Once the procedure is over and the patient is in recovery, each team member must confirm their part of the procedure was successful and that the patient is stable before leaving the procedure room.
How is Procedural Sedation performed
Doctors often use medications to ensure patients are relaxed, numb to pain, and possibly forget the medical procedure they’re about to undergo. The perfect drug for this purpose will quickly take effect but won’t last too long, allowing patients to recover and go home swiftly. Often, doctors use a combination of drugs. For instance, midazolam (which makes you relaxed and forgetful but doesn’t numb pain) is often combined with an opioid like fentanyl.
Here’s a simple explanation of the drugs commonly used:
Midazolam helps you relax and forget the procedure. It is usually given in the following quantities: starting with 2 to 2.5 mg and adding 1 mg every 2 to 5 minutes as needed. This drug typically starts working within 2 to 3 minutes and reaches its peak effect in about 5 to 10 minutes. Its effects usually wear off after about 1.5 to 2.5 hours. Midazolam can sometimes cause changes in thinking and memory, especially in older adults.
Fentanyl is a pain-relieving medicine given in small doses and adjusted as needed. It works in about 1 to 2 minutes and lasts for about half an hour to an hour.
Ketamine is another option. It starts working in about 1 minute and usually lasts between 5 to 15 minutes. Be aware that this medicine can sometimes cause side effects such as agitation upon waking, spasms of the voice box, and vomiting. It can also cause hallucinations, particularly in children, it’s best to avoid giving this medication to those predisposed to psychotic behavior.
Etomidate only works for about 5 to 7 minutes. Like midazolam, it can sometimes affect thinking and memory. It also doesn’t provide pain relief.
Propofol starts working after 15 to 30 seconds and stops working after 1 to 3 minutes. This medicine can cause slow or shallow breathing, but this can easily be managed with oxygen support. It can also cause a drop in blood pressure, which can be handled with IV fluids and ensuring you sit up slowly.
Dexmedetomidine starts working in about 3 to 5 minutes and works for about 15 minutes. This medicine doesn’t cause any breathing problems, but there’s debate over how effective it is as a sedative.
Methohexital begins working in about 15 to 30 seconds and lasts for about 4 to 7 minutes. It may cause shallow breathing or a drop in blood pressure, so breathing support or IV fluids may need to be provided.
Nitrous oxide, also known as laughing gas, is a relaxed, pain-relieving gas often used in dentistry. It works quickly and doesn’t last too long. It rarely causes nausea or vomiting and doesn’t affect normal reflexes. Nitrous oxide is usually given alongside oxygen, and although the amount a patient needs can vary, it generally shouldn’t exceed 50% of the gas mixture.
Possible Complications of Procedural Sedation
One basic idea when giving medical treatment is making sure we use the right medicine, in the right amount, for the right patient. Sometimes, this might mean using a stronger drug that works for less time, or picking a simpler treatment if there’s a chance of complications. This might seem a bit odd, but it’s a key part of our modern guidelines for giving medication to help patients relax for a procedure (sedation).
For instance, using a combination of drugs that work for a long time at high doses (like fentanyl and lorazepam) might seem safer than using propofol for short-term procedures. But this thinking can lead to mistakes and show misunderstanding of medical best practices. Avoiding this is really important for those in charge of giving medical staff their qualifications and for training bodies. This is because creating rules that aren’t based on medical evidence can result in risky shortcuts that could threaten the patient’s safety.
The point is, if complications arise during the procedure or the sedation part, it’s much easier and quicker to deal with complications from propofol than from fentanyl or lorazepam.
What Else Should I Know About Procedural Sedation?
Procedural sedation and analgesia (PSA) is a technique used to help patients bear short, painful procedures more comfortably. The key thing to remember is that it’s crucial for it to be done in a safe environment where the medical staff is ready to step in and handle any side effects of the sedation.
Breathing difficulties can occur as a result of PSA, so it’s important to watch this closely – a particular instrument, called an EtCO2 monitor, can help with this. It’s also okay if the medical team has to assist with the patient’s breathing, using a device known as a bag valve mask; this isn’t a negative outcome, it’s a necessary step to ensure the patient’s well-being.
Sometimes, sedation can cause low blood pressure. This is why it’s crucial to have an intravenous (IV) line set up to be able to quickly provide fluids that can bring blood pressure back up. Also, it’s safer to be cautious when changing the patient’s posture from lying down to sitting, as this can cause a drop in blood pressure as well. Plus, the medical team must be experienced in handling potential complications like vomiting.
