Overview of Laryngeal Mask Airway
A laryngeal mask airway (LMA) is a device, sometimes disposable or reusable, that’s used to keep an open passage for breathing. It’s used during the administration of anesthesia or as a life-saving tool for managing difficult or blocked breathing cases. It’s like a guideline chart for handling challenging breathing situations published by many anesthesiology societies worldwide.
The device was introduced into medical practice in the 1980s, primarily used in the operating room. But now, it is widely used in emergency departments, intensive care units, even in outdoor medical situations.
Compared to a bag-valve-mask, which is a breathing device used during emergencies, LMAs are easier to handle effectively, especially for basic life support providers. They can even replace intubation, which is a procedure to insert a flexible tube into the windpipe to maintain an open airway, when performed by advanced life support providers. Some versions of the LMA can even assist with placing the tube into the windpipe. [1][2][3]
Anatomy and Physiology of Laryngeal Mask Airway
The LMA or laryngeal mask airway is a device used to help people breathe by going through the mouth and into the part of the throat near the vocal cords. It creates a seal around the opening of the windpipe to allow for air to be pumped in. Health professionals use a trick to remember the challenges they might face when using this method: they call it “RODS”.
RODS stands for Restriction, Obstruction/Obesity, Disrupted or Distorted anatomy, and Short thyromental distance. ‘Restriction’ means that sometimes, breathing might be hard because of an airway that’s too narrow or a mouth that doesn’t open wide enough for the device to pass through.
‘Obstruction/Obesity’ means that if a patient has a blockage in their throat or are overweight, it will be difficult to correctly position the device. This is due to the fact that overweight patients often have more flesh in their throat, and this might not allow the device to sit properly. Also, larger patients may need more air pressure to breathe, which increases the chances of air leaking.
‘Disrupted or distorted’ means that if a patient’s throat has been changed from its usual shape, it may be difficult to put the device in the right place. And finally, ‘Short thyromental distance’ talks about patients with small lower jaw spaces. This can be hard because the positioning of the tongue can make it harder to use these kinds of devices.
Why do People Need Laryngeal Mask Airway
A laryngeal mask airway (LMA) is a tool used to help a person breathe. It can be used in a hospital setting during surgery, especially for patients who have been prepared ahead of time with empty stomachs. In emergency situations, healthcare providers might use the LMA as a temporary means to help a person breathe until a breathing tube can be inserted. This could be the case in situations where a person’s heart has stopped beating (cardiac arrest), or if the patient is so difficult to intubate that they aren’t getting enough oxygen.
The LMA is a good alternative to use in place of a face mask connected to a breathing bag. One of the reasons for this is that it helps to reduce the risk of filling the stomach with air, which in turn decreases the chance of vomiting and inhaling stomach content into the lungs (a condition known as aspiration). However, while it can reduce the risk of aspiration, an LMA isn’t as protective as a tube inserted directly into the windpipe (endotracheal tube).
An LMA is an effective way of helping a person breathe and should be used unless it’s not working in patients needing prolonged help with breathing.
LMAs are also a suitable tool for use in children and adults, as well as individuals who are overweight.
When a Person Should Avoid Laryngeal Mask Airway
The LMA, or laryngeal mask airway, can be a great substitute for having a tube placed into your windpipe to help you breathe, especially if you haven’t eaten beforehand. This method is used for selected patients and can sometimes lead to fewer complications than traditional intubation. However, there can still be serious complications, such as laryngospasm (uncontrollable muscle contractions in the throat), nausea, vomiting, aspiration (breathing in foreign material), and coughing. The LMA may trigger the gag reflex so it’s not advisable to use it if a patient is awake or aware.
Using the LMA may not be the best choice for everyone. It may not be suitable for patients with poor lung compliance (meaning the lungs are less flexible or unable to fully expand), high airway resistance (which makes it hard to breathe), disease in the throat, risk of inhaling food or fluid into the lungs, or obstruction in the airway located below the voice box (larynx).
Equipment used for Laryngeal Mask Airway
Laryngeal Mask Airway (LMA) is a type of breathing device doctors use during medical procedures. It’s a tube with an inflatable part shaped like an ellipse (elongated circle) that goes over a region in your throat called the supraglottic area. This helps keep your airway open so you can breathe better. It enables your breathing to happen naturally or through machine assistance.
While the first model of the LMA was reusable, the need for sterilization and the high price have pushed medical professionals towards using cheaper, single-use LMAs. These come in a range of different designs from a variety of manufacturers.
The first type of LMA had a design that included crossbars over the opening to stop the epiglottis (a flap in the throat) from slipping into it accidentally. However, this feature made inserting a breathing tube through the LMA difficult. These first-generation devices are still widely used due to their affordability and low rate of complications.
There’s a newer, second-generation LMA which is designed to create a better seal in the throat, without the need for crossbars. This new design allows easy tube insertion, and the ability to release or remove stomach contents safely. Some models even include a built-in bite block to prevent patients from biting down on the device.
A distinct model of LMA, known as the LMA Fastrach or the ILMA, was specifically created for situations where a breathing tube has to be inserted without the help of medical imaging. Offering both reusable and disposable versions, it has an additional handle for accurate positioning and a bar meant to lift the epiglottis out of the way for easy tube insertion. This particular LMA needs to be used with specific endotracheal tubes that come packaged with it.
Another unique LMA is the I-Gel device, which offers a non-inflatable, pre-shaped cuff. Made from a gel-like material, it doesn’t require inflation for placement, which might make it easier to insert. It also allows for the use of standard breathing tubes. The I-Gel is versatile, and can be used on patients of any age, from infants to adults.
Who is needed to perform Laryngeal Mask Airway?
Originally, the use of Laryngeal Mask Airways (devices used for keeping your airway open when you are put under anesthesia) was only handled by anesthesia providers – the professionals who are responsible for putting patients asleep during surgery. However, now, even people who are new to inserting these airways, professionals delivering emergency medical services, nurses, advanced healthcare providers, and doctors of many specialities have shown success in placing these devices. This success across a variety of medical personnel means that more people can ensure your safety and comfort during procedures that require anesthesia.
Preparing for Laryngeal Mask Airway
Before having a laryngeal mask airway (LMA) inserted, patients should ideally not have eaten anything for a certain period of time and have had a check for any factors that might make the procedure more difficult or which may suggest the procedure is not suitable. However, in emergency situations this may not be possible and the LMA can still be used as a backup plan. Different sizes of LMAs are available, and the size a doctor will choose typically depends on the patient’s weight. The package and the device itself usually have the suggested weight range printed on them. As a general guide for adults: size three is for those who weigh 30 to 50 kg, size four for those who weigh 50 to 70 kg, and size five for those who weigh more than 70 kg. If a patient’s weight is between two sizes, doctors will typically choose the larger size because it will provide a more effective seal, which is important for the success of the procedure.
How is Laryngeal Mask Airway performed
Before we start, the tool needs to be placed on a flat surface. To prepare it, we have to pump up and then totally deflate the cuff. This helps us make sure that the cuff isn’t wrinkled or folded. We’ll apply a type of lubricant that dissolves in water on both sides of the tool to make it slide in easily.
Next, if there’s no risk of causing injury to your neck, your neck will be stretched out slightly, like when you’re sniffing something. If needed, we could apply pressure to your jaw to help the process. The tool, also known as an LMA, will be gently pushed beyond your tongue.
Applications of backward pressure using the index finger and pressing the device against the hard upper part of your mouth ensure that it goes in fully. After that, the other hand is used to continue pushing the device inwards until it can no longer go any further.
Then, the collar/cuff of the device will be pumped up with specific amounts of air, depending on its size – around 20ml of air for a small-sized one, 30ml for a medium one, and about 40ml for the largest size. The amount of air might have to be adjusted to get a good seal and minimize any leaks of air.
After the cuff has been inflated, we check to make sure the device has been put in properly by connecting it to a special mask and delivering breaths, listening for breath sounds, and/or using tools that monitor carbon dioxide levels.
Sometimes, a tube, known as an endotracheal tube (ETT), may be inserted through most newly developed LMAs to help you breathe. These newer LMAs usually don’t have any bars or blockages at the end of the cuff, and usually seal better than older LMAs. There’s a particular LMA known as the Fastrach that’s meant for inserting the tube without needing to see where it’s going, and it’s more successful compared to the older versions. But, it might still fail in some cases. So, we often prefer to insert the tube under direct vision, using a tool called a flexible bronchoscope.
Regular endotracheal tubes might not be long enough to reach past your vocal cords when inserted through an LMA. To fix this problem, we could use a tube exchanger that slides over a flexible bronchoscope, or use a longer, special tube called a nasal RAE tube.
Possible Complications of Laryngeal Mask Airway
Sometimes when doctors try to insert a laryngeal mask airway (LMA), which is a device to help you breathe, the end of it might curl upwards. This can make it hard to put the LMA exactly where it needs to go. Some experts suggest filling the inflatable part of the LMA a little bit before putting it in or starting with the LMA upside-down and rotating it into place. These methods might stop the LMA from curling up. But, so far, there’s not enough evidence to say if these techniques actually work. Pushing the LMA in too forcefully might scrape the throat or cause it to bleed, and the LMA might fill the stomach with air. It’s also unclear if the LMA can stop contents from the stomach from being inhaled into the lungs.
So, if there’s a risk of vomiting and these stomach contents being aspirated (breathed into the lungs), the LMA should only be used temporarily or as a last resort. It should not replace a technique called endotracheal intubation, where a tube is inserted into the windpipe through the mouth or nose. It might also be hard to keep a proper seal if the patient’s breathing has high pressure. The LMA might move out of place during cardiopulmonary resuscitation (CPR) or if the patient is moved during transport. It’s important to keep the LMA in the middle.
LMAs are not a good first-choice for helping morbidly obese patients breathe because these patients need high airway pressure, which might cause leaks around the LMA. Also, if these patients breathe on their own through an LMA while under anesthesia, they might not breathe enough due to their position and the weight of their abdomen.
Fortunately, the chance of having problems with LMAs is low, and it’s less than the chance of problems with endotracheal intubation and using a bag valve mask, which is a device used to pump air into a patient who’s not breathing.
What Else Should I Know About Laryngeal Mask Airway?
LMAs, or Laryngeal Mask Airways, are devices used to help patients breathe. They have been found to work as well as other methods of managing a patient’s breathing during CPR (Cardiopulmonary Resuscitation). They can also be used effectively in children.
The success rate for a procedure called “blind intubation,” where a tube is inserted through an LMA to help a patient breathe, varies from 60 to 99%. This depends on the specific type of LMA used and the skill level of the medical professional. The best results are usually seen with an LMA model called “Fastrach”. However, this procedure is ideally done with the help of flexible fiber-optic guidance, a device that allows for improved visualization during the procedure.
An important thing to note is that LMAs shouldn’t be the final solution if there are difficulties securing patient’s airway, or pathway for breathing. LMAs have the potential to move out of place when transitioning from a temporarily stable situation to another breathing emergency. Therefore, they should be used as a temporary measure until a more secure airway is established using a device called an endotracheal tube.
