I recently started a new job on a paramedic ambulance to precept paramedic and EMT students. As I was going through and getting myself acquainted with the supplies and layout of the truck, I noticed that all of the pediatric endotracheal tubes up to size 6 were uncuffed. This was a little surprising to me. Why, you ask? When I first began my career, standard practice was to place an uncuffed ETT in all pediatric patients under 8 years of age. This has changed. In my current practice of transporting critically ill and injured pediatric patients to pediatric hospitals, the receiving physicians now prefer cuffed ETT’s. If our pediatric patients have an uncuffed tube in place, they usually replace it with a cuffed tube. This is not an isolated case. The National Emergency Airway Registry for Children evaluated 15 North American pediatric intensive care units to see which type of ETT was being utilized the most. Their study revealed that more than 90% of intubations were performed utilizing cuffed ETT’s. Though this is obviously the current trend, let’s consider the pros and cons of each type.
The narrowest point of a developing pediatric airway is the nondistensible cricoid cartilage. A properly sized uncuffed ETT will be large enough to create a good seal and small enough not to put pressure on the surrounding tissue; potentially creating a hypoperfusion injury. A larger size uncuffed ETT with a larger internal diameter can be placed when compared to a cuffed ETT that would require a smaller size due to the presence of a balloon. A larger uncuffed ETT provides less airway resistance and easier tracheal suctioning. Unfortunately, an uncuffed ETT is difficult to size correctly for each individual patient. The most commonly used formula is the modified Cole formula [4+ (age/4], but not all pediatric airways conform to this calculation. A study done by Khine et al. found that uncuffed ETT’s had to be changed out 30% of the time in children less than 2 and 18% of the time in children over 2. Too large of an ETT increases the risk of laryngeal damage, and too small of an ETT creates air leaks around the tube. Even a “correctly” sized ETT may have significant leaks. Initially, the leak around the tube may be minimal. Unfortunately, with the administration of sedatives and neuromuscular blockers, the air leak can increase. Even minor head movements can worsen the leak. Large air leaks lead to unreliable ventilation, oxygenation, airway pressure monitoring, and ETCO2 readings. Another major concern with cuffless ETT’s is the increased risk of fluid and emesis migrating around the tube, leading to aspiration. Fortunately, the use of a cuffed ETT can overcome most of these complications associated with cuffless tubes.
One of the main fears of using a cuffed ETT is causing damage to the surrounding tissue where the actual balloon is placed. This fear is based on the fact that damaged tissue can cause swelling on extubation, subsequently leading to stridor. In reality, studies have shown that there is absolutely no difference in post-extubation stridor when comparing ETT types. The exchange rate of cuffed tubes were actually 95% lower than uncuffed tubes. The sizing of cuffed ETT’s seems to be more reliable than that of uncuffed tubes. One study showed that the Khine formula [(age/4)+3] used to size cuffed ETT’s, compared to the modified Cole formula, resulted in 99% of tubes being appropriately sized. The modified Cole formula only achieved a 77% success rate. Accidental extubation is a top concern with any ETT type, especially in the pre-hospital setting. In theory, a cuffed ETT placed below the cricoid cartilage is less likely to be pulled out. This idea is based on the fact that the ETT balloon provides more resistance when pulled. A cuffless ETT provides no resistance, so it is more easily dislodged. Unfortunately, there is potential risk for airway damage with both types. With that considered, there is no significant data that shows cuffed ETT’s induce more injury.
A cuffed endotracheal tube reduces risks of aspiration, dislodgment, air leaks, and provides more reliable monitoring. The most reputable pediatric facilities in the world are now utilizing cuffed ETT’s the majority of the time. Unfortunately, this standard of care has not made it to some EMS agencies or non-pediatric specific emergency departments. Is this due to a lack of information, or is it because uncuffed ETT’s were the previous standard? As we know, there is a natural fear in going against what you were initially taught.
I am interested to hear from you. What does your service currently use, and what are your thoughts on the matter? Please be respectful when responding to this blog. Also, always remember to use your medical director and approved protocols to direct your practice before any information in this blog.
Crankshaw, D., McViety, J., & Entwistle M. (2014). A review of cuffed vs uncuffed endotracheal tubes in children. Pediatric Anesthesia and Critical Care Journal, 2(2), 70-73. doi:10.14587/paccj.2014.16
Litman, R. S., & Maxwel, L. G. (2013). Cuffed versus uncuffed endotracheal tubes in pediatric anesthesia: the debate should finally end. Anesthesiology, 118(3), 500-501. doi:10.1097/ALN.0b013e318282cc8f
Taylor, C., Subaiya, L., & Corsino, D. (2011). Pediatric cuffed endotracheal tubes: an evolution of care. The Oschner Journal, 11(1), 52-56. Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3096176/
Wiess, M. (2007). Uncuffed Versus Cuffed Endotracheal Tubes. Abstract SPA-APA Meeting San Francisco 2007. Retrieved from http://www2.pedsanesthesia.org/meetings/2007annual/syllabus/Faculty_Manuscripts/Weiss-Uncuffed%20versus%20cuffed.pdf