jagdkampf
02-24-02, 13:23
The basic airway modalites are first response measures and generally considered to be short term measures. The intermeadiate airway modalites are designed for use in difficult positions or where more prolonged respiratory support is necessary until definitive airway treatment is started. They can also be useful in controlling the airway when a difficult airway makes endotracheal intubation unlikely.
(1) The esophageal obturator airway
This is a tube that is pushed down the mouth and into the esophagus. A balloon is then inflated which blocks the esophagus. A mask assembly is pushed over the end of the extruding tube to seal the mouth and nose and ventilation is done via the connector at the end of the tube. These have fallen from favor in recent years because of the possibility of damage to the esophagus and because of the possibility of introducing the obturator into the trachea, thus occluding the airway. I don't recommend these because of the above pitfalls and generally they are difficult to use in an emergency.
(2) The laryngeal mask airway (LMA)
These were introduced in the anesthesia community but are beginning to find there way to EMS units. They are part of the difficult airway algorithm in ACLS now as well. They are a long tube with a rather bizzare looking inflatable ovoid mask at the end. The opposite end looks much like an endotracheal tube with the inflation bulb. These are inserted in the deflated position (technique varies a bit from practicioner to practicioner) by pushing the mask assembly into the mouth and down the oropharynx until it stops. The inflation bulb is filled with a set amount of air depending on the size of the LMA. The ovoid cuff creates a seal around the glottis and provides a very good airway. They range in size from 2.5 - 5 and are used in infants, children and adults. The down side is that they do not prevent aspiration of stomach contents, and they require some practice to acheive competency in placement and that they are not intended to be use for more than short periods of time (usually 2 hours or less).
(3) The combi-tube
This is my preferred airway device for field use. They are easy to use and very effective. The combi-tube is a tube with 2 cuffs and 2 lumens. The lower cuff is a low volume/high pressure cuff and the upper cuff is a high volume/low pressure cuff. The upper end of the tube has 2 lumens that resemble 2 endotracheal tubes melded together. To use this device you push it in through the mouth and down the oropharynx until a set reference point is reach. Then the lower cuff is inflated and ventilation through the lower lumen is attempted. If breath sounds are heard the tube is secured and no other measures are needed. You now have an endotracheal tube. If no breath sounds are heard and gurgling is heard over the epigastrium then the upper high volume/low pressure cuff is inflated and ventilation is attempted via the other lumen. This should provide you with breath sounds. The advantage of this system is in it's simplicity. Although, it sounds difficult, they are quite easy to use and we keep 2 different sizes on our emergency airway cart. The other advantage is that they separate the esophagus from the airway and provide a lumen to aspirate stomach contents with an NG tube. The only disadvantage I have seen so far is that I have not found them in pediatric sizes, although they may exist.
There may be other intermeadiate modalities out there but I am not familiar with them. If anyone knows of other devices, please include them here. Any questions?
Jag
(1) The esophageal obturator airway
This is a tube that is pushed down the mouth and into the esophagus. A balloon is then inflated which blocks the esophagus. A mask assembly is pushed over the end of the extruding tube to seal the mouth and nose and ventilation is done via the connector at the end of the tube. These have fallen from favor in recent years because of the possibility of damage to the esophagus and because of the possibility of introducing the obturator into the trachea, thus occluding the airway. I don't recommend these because of the above pitfalls and generally they are difficult to use in an emergency.
(2) The laryngeal mask airway (LMA)
These were introduced in the anesthesia community but are beginning to find there way to EMS units. They are part of the difficult airway algorithm in ACLS now as well. They are a long tube with a rather bizzare looking inflatable ovoid mask at the end. The opposite end looks much like an endotracheal tube with the inflation bulb. These are inserted in the deflated position (technique varies a bit from practicioner to practicioner) by pushing the mask assembly into the mouth and down the oropharynx until it stops. The inflation bulb is filled with a set amount of air depending on the size of the LMA. The ovoid cuff creates a seal around the glottis and provides a very good airway. They range in size from 2.5 - 5 and are used in infants, children and adults. The down side is that they do not prevent aspiration of stomach contents, and they require some practice to acheive competency in placement and that they are not intended to be use for more than short periods of time (usually 2 hours or less).
(3) The combi-tube
This is my preferred airway device for field use. They are easy to use and very effective. The combi-tube is a tube with 2 cuffs and 2 lumens. The lower cuff is a low volume/high pressure cuff and the upper cuff is a high volume/low pressure cuff. The upper end of the tube has 2 lumens that resemble 2 endotracheal tubes melded together. To use this device you push it in through the mouth and down the oropharynx until a set reference point is reach. Then the lower cuff is inflated and ventilation through the lower lumen is attempted. If breath sounds are heard the tube is secured and no other measures are needed. You now have an endotracheal tube. If no breath sounds are heard and gurgling is heard over the epigastrium then the upper high volume/low pressure cuff is inflated and ventilation is attempted via the other lumen. This should provide you with breath sounds. The advantage of this system is in it's simplicity. Although, it sounds difficult, they are quite easy to use and we keep 2 different sizes on our emergency airway cart. The other advantage is that they separate the esophagus from the airway and provide a lumen to aspirate stomach contents with an NG tube. The only disadvantage I have seen so far is that I have not found them in pediatric sizes, although they may exist.
There may be other intermeadiate modalities out there but I am not familiar with them. If anyone knows of other devices, please include them here. Any questions?
Jag