The anatomical structure of a pediatric patient’s airway differs from an adult patient’s, so when it comes time to intubate, special care using laryngoscopes can help.
By Phyllis Hanlon
Laryngoscopy and intubation in pediatric patients have been part of the medical landscape since the 1960s. But in spite of a 50-plus-year history, airway management in pediatric patients still poses a challenge. While intubation devices have become more refined and sophisticated through the years, a child’s anatomy, developmental stage, weight, and size still impact the ease or difficulty of successfully performing the procedure.
Pediatric vs Adult Anatomy
The normal pediatric airway comprises the larynx and hyoid bones with single cartilages (ie, thyroid, cricoid, epiglottis) and paired cartilages (ie, arytenoids, corniculates, and cuneiform). A child’s larynx is more rostral and situated higher in the neck than an adult’s; the tongue is also relatively larger than an adult’s and could obstruct the clinician’s view of the airway, preventing clear visualization of the larynx.
The vocal cords are angled so nasal intubations could result in lodging the endotracheal tube in the anterior commissure rather than the trachea; the epiglottis is also shaped differently, angled away from the axis of the trachea, which complicates efforts to lift the epiglottis with the laryngoscope blade.
A child’s physiology contributes to the difficulty in intubation as well. Since the integrity of an infant’s or small child’s cartilage affects the trachea, larynx, and bronchi, dynamic airway compression might occur, which decreases the diameter of the airway and increases negative inspiratory pressure, ultimately affecting breathing. This scenario creates a cycle, which may lead to respiratory failure.
The American Society of Anesthesiologists (ASA) Practice Guidelines note that airway management in the pediatric patient may require an approach that would be used in an uncooperative patient, for instance, intubation attempts after induction of general anesthesia.
Additionally, due to the above-mentioned pediatric anatomical structures and physiology, clinicians might consider the airway in this patient population to be “difficult.” Moreover, clinicians who have access to previous medical history or medical records may better understand an existing issue in a patient; however, with a child, no such records may exist.
Another challenge clinicians face with a pediatric patient is forced residual capacity (FRC), which, in an awake infant, is similar to an adult’s when normalized to body weight. However, under anesthesia, an infant’s FRC is decreased and desaturation occurs more quickly.
Positioning can also affect FRC. Supine patients, typically the case with infants and small children, may experience a decrease of up to 30%; FRC is also affected when the contents of the abdomen push against the diaphragm. The chest wall in a pediatric patient is compliant, the thoracic cage is small, and the abdomen contains a large amount of contents. During the preoxygenation process before intubation, FRC further reduces the amount of time allowed to establish an endotracheal tube prior to desaturation.
Direct laryngoscopy has been, and still is in some cases, the gold standard for intubation with pediatric patents. Some manufacturers have designed laryngoscopes in pediatric sizes that afford improved glottic views.
However, video laryngoscopy is changing the way clinicians manage airway situations. The newer devices promise to deliver larger, brighter, and higher resolution images, which ultimately achieve the same or higher intubation success rates, often in less time, than direct laryngoscopy. Some popular models include the AirTraq optical laryngoscope, GlideScope video laryngoscope, and VividTrac Pediatric.
Pediatric Devices
The AirTraq SP offers two versions of its direct laryngoscope: an infant version and a pediatric version. These models feature a dual viewing system: a guided channel delivers ETT to the glottic opening using a wireless camera and display recorder or the user can look directly through the eyecup. The Wi-Fi camera has a rotating screen that flips to capture images from multiple positions. It records the intubations and can share real-time images with a PC, iPhone, or iPad. Both models also have an antifog system that warms the lens to body temperature.
The GlideScope AVL Preterm/Small Child video laryngoscope, from Verathon Medical, also offers a clear, real-time view of the airway and tube placement and is optimized for use in the neonatal intensive care unit (NICU), operating room, and emergency department (ED). The GlideRite stylet complements the angle of the GlideScope video laryngoscope. An on-board “4-Step Technique” tutorial facilitates proper use of the device.
Meanwhile, Vivid Medical Inc recently introduced its VividTrac Pediatric Model VT-P100 single use video laryngoscope for children ages 4 to 8. The device’s USB-based “open system” architecture makes it compatible with a variety of display options, including low cost tablets.
The video images facilitate success rates on the first attempt, and an integrated ET tube channel provides an easy way to advance the preloaded ET tube into the oral cavity and trachea. A three-foot integrated USB cord allows for more flexibility, and built-in antifogging capability ensures unobstructed viewing throughout the procedure.
Mina Farr, founder, president, and CEO of Vivid Medical, explained that VividTrac is equipped to handle all airways with equal dexterity.
“The beauty of our device is that both difficult and normal airways look pretty much the same with the VividTrac Grade 1 view of the airway, and our channels help guide the tube into the trachea very easily. So unlike other devices with which you may see the airway then encounter challenges with tube placement, our device works more like a ‘point and shoot camera,’” she said.
“As you insert the device and see the airway, the tube is guided in the same direction, so all you have to do is advance the tube in the channel with minor alignment of the tube or device to pass the tube through the vocal chords.” Farr added that even the most anterior airways look normal to the user so the method is the same in all cases.
Unlike many other models, VividTrac does not require the user to tilt the patient’s head, do a jaw thrust, or use force to perform the intubation.
“The patient can thus be intubated while wearing a C-collar or, if in an accident, without any neck manipulation,” said Farr. “Also, since our display is independent of the VividTrac computer, tablet, or mobile phone, the patient can be intubated in any position, even inside a rolled away car, before the neck and C-spine are secured.”
The “no force” technique is well tolerated, even in awake patients, and makes VividTrac one of the safest devices on the market today, she added.
Most devices with a metal stylet ET tube require clinical experience since the user must guide the tube with a free hand motion. Farr pointed out that the VividTrac already has the tube in the channel and is visible 100% of the time.
“So it is very easy to guide the tube in, and a lot faster to do intubation with the VividTrac,” she added. “Our device allows, for the most part, a single-handed operation, meaning the other hand can be used to introduce suction concurrent to intubation or to grab foreign objects out of the child’s mouth prior to intubation under visualization.”
Farr added, “Since we do not need a stylet, oxygen can be attached to the ET tube that is inside the VividTrac channel ‘during the intubation.’ This allows oxygen to be available concurrently.”
Farr recommended training on a manikin for a few minutes before using the device on a patient. The training and patient-use videos at the company’s eLearning site also can help acclimate the user to the device’s capabilities.
“In practice, it takes about one to three intubations for our users to be very comfortable with the VividTrac,” she said. During the procedure, VividTrac records video, which can readily be transferred to patient medical records or used for educational and training purposes.
Video vs Direct Laryngoscopy
Researchers have conducted several studies in an attempt to discern differences between video and direct laryngoscopy. A 2012 study1 examined first-attempt intubation success and glottic visualization in children using video laryngoscopy versus direct laryngoscopy. In this cross-sectional study, 26 fellows and faculty in pediatric emergency medicine performed 156 intubations on simulators.
First attempt success rates were 88%, 79%, and 60% in neonates, infants, and adults, respectively. Additionally, findings showed a significantly improved percentage of glottic opening (POGO) score in all three simulators with video laryngoscopy. Overall, video laryngoscopy was found to be superior to direct laryngoscopy.
On the other hand, researchers from Shanghai found contradictory results in their meta-analysis2 of randomized controlled trials in infants, neonates, and children that compared video laryngoscopy to direct laryngoscopy. The study evaluated 14 studies involving AirTraq, GlideScope, Storz, TruView, AWS, Bullard, and McGrath pediatric laryngoscopes.
The analysis found that although video laryngoscopy improved glottic visualization in the majority of children with normal airways or potentially difficult intubations, the time to intubate (TTI) was longer when compared with direct laryngoscopy. Additionally, video laryngoscopy was associated with a higher failure rate.
The study authors pointed out that further studies are needed to determine the efficacy and safety of video laryngoscopy when used by nonexperts and in pediatric patients with airway problems.
A 2011 study3 focused on the GlideScope and issued mixed results. The authors found the device inferior to standard laryngoscope when used by pediatric residents under simulated normal and difficult airway conditions. However, the findings cited the GlideScope as potentially safer for upper jaw injury and advantageous in managing the complicated airway.
Game Changer
Earlier this year, the JHB Hope Foundation, a global outreach ministry and part of Jesus House Baltimore, donated a pediatric GlideScope to Northwest Hospital, a LifeBridge Health Center, in Randallstown, Md. Jonathan S. Thierman, MD, Emergency Department Physician, explained that the hospital’s ED sees some 60,000+ patients every year, 14% of whom are pediatric patients.
The pediatric GlideScope will serve a true need and make a big impact at the facility, he said. “We don’t often do [pediatric] intubation and previously didn’t have that tool. But when we do need it, it will be extraordinarily helpful.”
According to Thierman, pediatric patients who present at Northwest with asthma or respiratory syncytial virus (RSV) exacerbations are typically sent to Sinai Hospital in Baltimore, another LifeBridge Health Center, which has a dedicated pediatric emergency department.
In the past, Northwest used direct laryngoscopy when needed for pediatric patients. “It’s so difficult to intubate a young child. We didn’t have video laryngoscopy before. The GlideScope takes the procedure to a whole new level. It’s a game changer for intubating airways,” Thierman added.
Northwest Hospital already had a GlideScope for adults and all staff had been trained on the device. “We used video GlideScope to visualize and remove a bagel in an adult patient’s airway. The procedure was a lifesaver that day for the patient,” Thierman said. The device should be of significant importance since children often ingest items that cause choking, he added.
When it came to selecting a particular model, Northwest Hospital chose GlideScope, citing it as an “industry leader.” Thierman added, “Also, we already had half the system. It was a matter of getting the blades to connect to the current system.”
Clinicians at Northwest use video laryngoscopy routinely with normal airways to ensure a high comfort level, should a patient with a difficult airway need intubation. “If you use it all the time for a normal airway, it’ll make use on a difficult airway easier,” said Thierman, pointing out that children, by nature, can be challenging to intubate.
While the hospital is thrilled with the donation, getting used to the device does take some time, according to Thierman. “The physician is manipulating the tool while standing upright, looking at the screen instead of peering into the patient. You’re watching the impact on the screen while using your hands. When you get used to it though, it makes a big difference,” he said.
Additionally, using video laryngoscopy becomes a team effort. “You have four sets of eyes watching and confirming tube placement. If one physician sees swollen glands or some other obstruction, he can let others know. You have more confidence with that kind of support.”
Although clinicians have no control over a child’s anatomy, physiology, and physical structure, they have a variety of tools from which to choose when pediatric intubation becomes necessary.
RT
Phyllis Hanlon is a contributing writer to RT. For further information, contact [email protected].
| Pediatric Nasal Intubation A clinician from Boston Children’s Hospital discusses the use of endoscopy during pediatric nasal intubation. By Phyllis Hanlon As a nurse practitioner at Boston Children’s Hospital, Micayla Hinds, MSN, CPNP, PNP in ENT, has performed her share of pediatric intubations. She does most of these procedures on an outpatient basis when patients present with possible adenoid hypertrophy, reflux, vocal chord function/structure or Eustachian tube function/structure. Hinds pointed out that the majority of laryngoscopy she performs is flexible and done through the nose. “I am most familiar with and prefer the Storz flexible endoscopes,” she noted. While a distal chip scope provides a clearer image than a flexible fiberoptic laryngoscope, Hinds noted that children have difficulty tolerating the latter devices. Although she is experienced, Hinds explained that working with children requires not only technical and clinical skills, but also the ability to calm anxiety. “When having to use a flexible endoscope to perform a laryngoscopy on a child, the biggest challenge is cooperation and fear of the unknown,” she said. “I am a pediatric nurse practitioner, so have never done this on an adult, but when observing the procedure in an adult, I do notice that they are much more cooperative and less scared [than children] for the most part.” Just as with any type of intubation tool, training on endoscopes involves lots of practice and becoming familiar with the equipment, according to Hinds. While complications during nasal intubation procedures are usually minimal, there are some potential adverse effects. Mild to moderate bleeding and damage to surrounding structures, such as retropharyngeal perforation could occur, Hinds said. |
References
- Donoghue AJ, Ades AM, Nishisaki A, Deutsch ES. Video laryngoscopy versus direct laryngoscopy in simulated pediatric intubation. Ann Emerg Med. 2013;61(3):271-7. doi: 10.1016/j.annemergmed.2012.09.008. Epub 2012 Oct 18.
- Sun Y, Lu Y, Huang Y, Jiang H. Pediatric video laryngoscope versus direct laryngoscope: a meta-analysis of randomized controlled trials. Paediatr Anaesth. 2014;24(10):1056-65. doi: 10.1111/pan.12458. Epub 2014 Jun 24.
- Fonte M, Oulego-Erroz I, Nadkarni L, et al. A randomized comparison of the GlideScope video laryngoscope to the standard laryngoscopy for intubation by pediatric residents in simulated easy and difficult infant airway scenarios. Pediatr Emerg Care. 2011;27(5):398-402. doi: 10.1097/PEC.0b013e318217b550.
