Pediatric Medical Resuscitation – The Airway
- Mar 17th, 2015
- Geoff Jara-Almonte
Pediatric Medical Resuscitation Pearls and Pitfalls: The Airway
Author: Geoff Jara-Almonte, MD // Editor: Alex Koyfman, MD (@EMHighAK)
You are one hour into your overnight shift at a single-coverage semi-rural emergency department when you are paged overhead to the resuscitation room. As you come in you see your triage nurse rushing back with a young couple holding a boy who looks to be about two years old. He is in severe respiratory distress. You place him on the monitor, his vital signs are HR 145, SpO2 95%, tympanic temperature 36.7, he is breathing 32 times a minute. You place him in his father’s lap on the stretcher and examine him. His neck is flexed and head extended. He has supraclavicular retractions and nasal flaring. His lungs are clear, there is soft inspiratory stridor. No trismus, the oropharynx looks normal, neck is supple with no adenopathy or masses. You try and decide what is causing his respiratory distress . . .
In children the combination of history and exam is often sufficient to determine the cause of respiratory distress as well as assess the degree of severity. Particularly helpful findings include:
- Stridor- suggestive of upper airway obstruction; respiratory phase may help localize lesion:
- Inspiratory – obstruction in supraglottic area or immediately at the level of the glottis
- Biphasic – obstruction in the trachea
- Expiratory – carina or below
- Retractions may be subtle, require careful observation of unclothed child, indicate increased work of breathing. Tend to progress from inferior to superior with increasing distress.
- Tachypnea – may be the only sign of significant respiratory distress, especially in young infants. Prolonged observation is necessary, as periodic breathing can lead to under- or overestimation.
- Position – sniffing position indicates airway obstruction, tripoding usually with lower airway pathology.
- Nasal Congestion – can precipitate significant respiratory distress in neonates and infants under 4 months of age who are obligate nasal breathers
- Grunting – creates PEEP usually indicates alveolar pathology
- Nasal Flaring – reflexive activity, usually with upper airway obstruction.
- Paradoxical or see-saw breathing – chest collapse and abdominal protrusion during inspiration is an ominous sign of respiratory muscle fatigue.[i]
- Head Nodding – associated with impending respiratory failure and mortality[ii]
You decide he likely has an upper airway obstruction of some sort. You get a bit more history from the parents – they tell you he has no medical problems, and was in his usual state of health until tonight. He was playing with his older sister in her room unsupervised for about ten minutes when they heard crying. They rushed in and found him in distress. You quickly run over the differential of acquired upper airway obstruction in children . . .
- Epiglottitis – Usually febrile and toxic-appearing. Rapid onset, present after <24 hr of symptoms. Drooling, trismus, odynophagia, and respiratory distress are common presentations.
- Retropharyngeal and parapharyngeal abscesses – Often polymicrobial, associated with sore throat, high fever, muffled voice, trismus, and neck stiffness, usually less than 3y/o
- Croup – Most common cause of obstruction, peak at 2yr. Harsh barking cough, inspiratory stridor, preceded by URI. Usually worse at night and improves in cold air
- Bacterial tracheitis – usually viral prodrome, may have acute onset of respiratory distress. Febrile, sometimes toxic appearing. Difficult to differentiate from croup and epiglottitis.
- Aspirated foreign body – Sudden in onset, no associated infectious symptoms. Peak age in toddler years. Variable history of choking episode.[iii]
Based on this history you suspect an aspirated foreign body. As you are trying to decide what to do next you place him on a non-rebreather. He gets upset with the mask on his face and fights to take it off. As he is crying and becoming more distressed, you hear his stridor worsening. He begins to have severe retractions, and you notice some perioral cyanosis. His pulse ox drops to the 80s. You try and decide if it’s more important that he have the O2 mask on, or that he be comfortable . . .
Agitation and crying can precipitate worsening respiratory distress and decompensation of a tenuous patient. Crying and hyperventilation lead to increased minute ventilation, which in turn leads to increased airflow velocity across the site of obstruction. As airflow velocity increases, there is increasingly negative intraluminal pressure (Bernoulli’s principle). As intraluminal pressure drops, there is worsened dynamic inspiratory collapse of the pliable airway soft tissues, which leads to worsened obstruction and increasing distress. [iv]
Keeping your patient as calm as possible can reduce the possibility of sudden decompensation. Allow the child to maintain a position of comfort. Allow him to sit in a parent’s lap or be near a parent if at all possible. Minimize noxious stimuli such as blood-pressure cuffs, rectal thermometers, phlebotomy, and oxygen masks or nasal cannula as much as possible. Try alternatives like blow-by oxygen or nebs. Consider inhaled steroids for croup. Try to limit the number of caregivers in the room. Remember that children take their behavioral cues from their parents, and the parent will take them from you. Be as calm and reassuring as possible. Allow the child access to a favorite toy, video game, or phone.
You decide to allow him to take off the mask. You have the father hold it and give blow-by oxygen. Over the next few minutes he stops crying. His stridor and retractions improve a little. But he remains distressed, and seems worse than when he came in. You consider trying the Heimlich maneuver or looking in the mouth to see if there is a foreign body you could remove, but then you wonder if that would be a good idea . . .
The preferable treatment for a child with a partially obstructing foreign body is endoscopic or surgical removal in the OR under controlled circumstances. So long as it remains a partial obstruction – the child is breathing, crying, or phonating and has adequate mental status – it is best to disturb him as little as possible. Allow him to remain in a position of comfort, keep him and the parents calm, and get him to the OR as soon as possible. If the child is coughing that is probably the most effective way to clear an obstructing foreign body. Relief maneuvers or attempts at removal risk converting a partial obstruction to complete. Meanwhile prepare your equipment and team in case he does decompensate.[v]
You decide your first priority is to avoid making things worse. You leave him sitting on his father’s lap. You page ENT and continue to observe him as you wait. He is having increasingly frequent periods where he will desat to the 80s. You realize he may decompensate before ENT arrives. You wonder if there is anything else you could try at this point. . .
Heliox may have a benefit in upper airway obstruction secondary to croup.[vi] It has been tried in cases of foreign body obstruction with some success in at least one case.[vii] Consider this for a patient with an incomplete obstruction and signs of distress.
You decide to call for heliox, but your RT says it will be at least 20 minutes until they can get there. Suddenly the child stops making any noise, you see he is not making any effective respiratory effort. You realize he now has a complete obstruction. His father looks at you terrified; the boy looks wide-eyed and scared. Your nurse looks at you expectantly…
In a conscious patient with a complete airway obstruction, the first step is to attempt relief maneuvers to try and expel the foreign body. In patients over one year old perform abdominal thrusts. In patients younger than one year, do chest compressions so as to avoid injuring the liver.[viii] Do not perform a blind finger sweep.
You guide the father out of the way and get behind the patient. You give several hard abdominal thrusts, but without any relief. After several thrusts the child goes limp in your arms. You realize he has lost consciousness. You need to do something else. . .
If the patient loses consciousness, the next step is to attempt direct- or video laryngoscopy for visualization and removal of the foreign body. Use a Magill forceps, Kelly clamps, or any other instrument on hand to remove it if seen. Paralysis is indicated only if the jaw is clenched. Laryngoscopy should not be delayed for sedation. Remember the characteristics of the pediatric airway that may make DL different than in adults.
- Relatively Large Occiput – the optimal position for bagging and intubation is still the sniffing position with the external auditory canal level with the sternal notch. Infants and small children will likely need a shoulder roll. School-aged children may need no support, and adolescents may need support under the head as in adults.
- The Epiglottis – traditional teaching advocates use of the Miller blade to better control the redundant, floppy and omega-shaped epiglottis, however a recent study found the Mac blade, when used to lift the vallecula, gave as good of a view as the Miller[ix]. Use whichever blade and technique you are most familiar with.
- More anterior larynx – when intubating focus on looking anteriorly rather than going deeper.
- Smaller field of view – ensure that you introduce the ETT from the side rather than directly down your field of view. Use a pediatric stylet, but beware that the tip of the stylet does not project beyond the end of the tube to avoid traumatizing the airway.
- Micrognathia – may be subtle, but can make intubation much more difficult. The forehead, maxilla and chin should all lie in the same plane. If the chin is posterior to this plane, there is some degree of micrognathia, suspect a difficult airway.[x]
- Short Airway – there is a much shorter distance between the vocal cords and carina. Simple hyperflexion or -extension of the head can dislodge the tube and potentially result in inadvertent extubation. Secure the tube well and consider a cervical collar to stabilize the head, especially during transport.[xi]
You quickly place a small shoulder roll and take the #2 Mac and slowly advance it along the tongue until you have the tip in the vallecula. You lift the epiglottis and have a good view of the cords but do not encounter any foreign body. You look up and see his SpO2 is 60%. You pull out the laryngoscope and try and decide what to do next . . .
If you do not encounter the foreign body on DL, the next step is to attempt ventilation with the BVM. Positive pressure ventilation may be successful even in cases of apparently complete obstruction because it avoids creating negative intraluminal pressure and dynamic inspiratory collapse.
- The tongue is larger relative to the mouth, and the airway is more likely to obstruct from posterior displacement of the tongue. This can be easily corrected with manual positioning or an oral airway. Manipulate only the bony prominences; even minimal external pressure on the trachea or glottic structures can cause collapse of the airway.
- Make sure you have the appropriate sized bag – the neonatal bag will not provide adequate tidal volumes for older toddlers and children; the adult bag will give far too much volume and risk baro- and volutrauma.
You perform a careful head-tilt and chin lift and try bagging, but there is no air entry. You quickly grab an oral airway and place it. You try bagging again, but still there is no air entry. His SpO2 is 52% now and his HR has dropped to 100. You ask your nurse to draw up 0.01 mg/kg of epinephrine anticipating an impending PEA arrest. You realize the situation is dire and you have only a few things left to try . . .
If you suspect a relatively soft foreign body such as a piece of meat or a balloon, removal by deep tracheal suctioning could be attempted next. Use an ETT cut transversely just proximal to the side port; attach this to a meconium aspirator connected to wall suction. Intubate the trachea, advance slowly occluding the suction port of the aspirator, if you feel a sudden resistance to inflow of air from the tube, slowly withdraw. If not successful you can remove the suction apparatus, inflate the balloon, and attempt to ventilate.[xii]
Walls recommends forcible right mainstem intubation of the foreign body as the next step. He describes two techniques
- In children – insert the tube with stylet as far as it will go, then withdraw to the appropriate ETT depth and attempt to ventilate[xiii]
- In adults – intubate to appropriate depth and attempt to ventilate. If unsuccessful, replace stylet, advance tube as far as possible, and try again to ventilate (in case the foreign body is soft or friable and you have pushed through it with the tube). If still unsuccessful withdraw to the appropriate ETT depth and attempt to ventilate again[xiv].
- If at this point you still cannot ventilate there are two situations which are potentially survivable: either the tube has become obstructed by the foreign body, or there is a unilateral mainstem obstruction and a contralateral tension pneumothorax. Consider replacing the tube and attempting bilateral thoracostomies.
You again insert the laryngoscope and identify the cords. You insert the 4.5 tube with the stylet and advance it as far as possible. Once you feel firm resistance you slowly withdraw until you see the two parallel marks on the tube at the glottis. You withdraw the stylet and start to ventilate. You meet significant resistance. You try to stay focused as the pulse ox alarm goes off and his heart rate drops to toward 60. You withdraw the tube and see some hot-dog meat stuck in the end. You grab a new tube out of the airway box and re-intubate him. This time when you attempt to ventilate he bags fairly easily. You have good EtCO2. You fight your urge to bag too fast, and slowly his sats improve to 95% and his heart rate comes up.
Your ENT consultant comes in and takes him to the OR and is able to remove several large chunks of hot dog from the right mainstem bronchus. The child makes a complete recovery. Afterward during the debriefing, your nurse asks why you didn’t do a surgical airway.
If on direct laryngoscopy you do not see a supraglottic foreign body or anything immediately below the cords, then the obstruction is likely in the trachea or at the level of the carina; a surgical airway is unlikely to be beneficial in this scenario – cricothyrotomy either open or needle – will bypass an obstruction only if it lies in the small space below the cords but above the cricoid cartilage. It is more likely that an obstruction not visible from above lies more proximally. A surgical airway is not likely to be more effective than endotracheal intubation, however it remains a possibility as a last ditch effort.[xv]
Open cricothyrotomy is contraindicated in children under 10 years of age due to underdevelopment of the cricothyroid membrane. The preferred surgical airway technique for children under 10 years of age is needle cricothyrotomy. A full review of the technique is beyond the scope of this discussion however there are a few pearls to keep in mind:
- Be familiar with your equipment before you need it. Commercial jet ventilation systems can be confusing to set up.
- If using an IV angiocath, use 14 gauge or larger
- The end of the catheter is several millimeters behind the end of the needle, so it is possible to advance the tip of the needle into the trachea and aspirate air while the tip of the catheter remains in the soft tissue. Attempting to advance the catheter in this position risks creating a false tract in the pretracheal soft tissue. Consider passing a wire through the needle and advancing the catheter over this with the needle in place to avoid this complication.
- After removal of the needle confirm again that the catheter is in the trachea before attempting to ventilate. Insufflation of air into the soft tissue of the neck will significantly distort the anatomy and make further attempts at a percutaneous or surgical airway extremely difficult or impossible
- In children less than 4 – 6 years of age, avoid jet ventilation instead ventilate with a BVM attached to the catheter. Caution should be used if jet ventilating older children due to the risk of barotrauma. Children up to 10 years or 30kg can likely be adequately ventilated with a BVM rather than jet device.[xvi]
- To connecttheBVM to the catheter:
- Use a 3.0mm ETT adapter with the angiocath directly
- Attach a 3mL syringe to the catheter, and use an 8.0 ETT adapter.[xvii]
- The peak pressure required to oxygenate through an angiocath are well above what is allowed by the pop-off valves on most BVM. Make sure you disable it.
- In the setting of complete upper airway obstruction, expired air can only exit through the catheter. Allow long expiratory times, there is significant risk of breath-stacking and barotrauma
The following algorithm for management of airway foreign body in a pediatric patient is adapted from Walls et al Manual of Emergency Airway Management[xviii]
1: Partial obstruction => to OR for bronchoscopy and removal (consider heliox to temporize)
↓ Progresses to Complete
2: Relief Maneuvers: chest thrust < 1y/o, abdominal thrusts if > 1yo
↓ loses consciousness
3: Direct laryngoscopy and attempt at removal
4: Attempt to ventilate → if successful, to OR
5a: Consider tracheal suction → if successful, to OR
5: Intubate and attempt to advance FB into mainstem bronchus → if successful to OR
6: Needle cricothyrotomy → if successful to OR
|Pediatric Airway Equipment Sizing|
|Blade||6 -11kg – #112- 23 kg – #223 – 40 kg – #3|
|ETT||4 + (Age in years / 4) [Subtract 0.5 – 1 if using a cuffed tube[xix]]|
|ETT depth||– 3x tube size(Age in years / 2) + 12
– Double lines of the tube at the glottis
|Oral Airway||Measure from mouth to angle of mandible|
|Nasal Airway||Tip of nose to tragus|
|LMA||Package has recommended weight ranges|
The pediatric bougie cannot be used with tubes smaller than 4.0[xxii]
[i] Fleisher, Gary R., and Stephen Ludwig, eds. Textbook of pediatric emergency medicine. Lippincott Williams & Wilkins, 2010. p 560
[ii] Tiewsoh, Karalanglin, et al. “Factors determining the outcome of children hospitalized with severe pneumonia.” BMC pediatrics 9.1 (2009): 15
[iii] Marx, John A., et al., eds. Rosen’s Emergency Medicine-Concepts and Clinical Practice,. Elsevier Health Sciences, 2010. pp 2104-14
[iv] Walls, Ron M., and Michael Francis Murphy, eds. Manual of Emergency Airway Management. Lippincott Williams & Wilkins, 2012. Pp 276 – 280
[v] Walls, pp 316 – 317
[vi] Moraa, Irene, et al. “Heliox for croup in children.” status and date: New search for studies and content updated (conclusions changed), published in 12 (2013).
[vii] Brown, Lance, et al. “Heliox as a temporizing measure for pediatric foreign body aspiration.” Academic emergency medicine 9.4 (2002): 346-347.
[viii] Rosen’s p2113
[ix] Varghese, Elsa, and Ratul Kundu. “Does the Miller blade truly provide a better laryngoscopic view and intubating conditions than the Macintosh blade in small children?.” Pediatric Anesthesia (2014).
[x] Walls, Ch 25,26
[xi] Walls, p 285
[xii] Ruiz, E, et al. The Benchmark Laboratory Manual for Emergency Medicine; 8th ed. Hennepin County Medical Center pp. 63-4
[xiii] Wall, p318
[xiv] Walls pp420-22
[xv] Walls p318
[xvi] Walls pp298-99
[xvii] Fleischer p. 81
[xviii] Walls, p 319
[xix] Fleischer p 10
[xx] Walls Ch 24
[xxi] Fleischer p 11