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These gross pathology images show a fleshy papillary mass with white pinhead-sized spots on the surface, filling the nasal cavity and oropharynx and thereby presenting a difficult airway, in a geriatric patient with recurrent rhinosporidiosis.
Emergency airway management is significantly associated with life-threatening complications and other adverse events, particularly when it takes place outside the setting of a surgical suite.[1,2] Many factors must be taken into account to ensure a timely, safe, and successful intubation in individuals with respiratory distress, including the patient's anatomy, physiology, and comorbid conditions.
See the following slides for discussions of these and other important considerations of emergency airway management in three groups who may present challenges to intubation—the elderly, obese, and pediatric populations.
Images courtesy of Khan I, Gogia S, Agarwal A, Swaroop A. Case Rep Otolaryngol. 2014;2014:609784. [Open access.] PMID: 25574413, PMCID: PMC4276699.
The patient whose contrast coronary angiogram is shown would likely be at high risk for cardiac ischemia during intubation. The image demonstrates a right anterior oblique cranial view of the left coronary system. The red arrow indicates diffuse disease in the mid and distal left anterior descending artery; the yellow arrow reveals a 60% lesion in the mid-circumflex coronary artery.
Geriatric Patients
An elderly person who presents in respiratory distress may require invasive airway management. To ensure a safe and effective intubation, clinicians must be aware of, and evaluate, a variety of potential preexisting conditions—such as the presence of a long-term smoking history, obstructive sleep apnea (OSA), hypertension, and/or coronary artery disease—which are very prevalent in seniors and which can increase their susceptibility to complications during airway management. In addition, physiologic and anatomic changes that occur with aging may cause airway management to be more difficult in the elderly.[3,4]
Adapted image courtesy of Charoenpanichkit C, Hundley WG. J Cardiovasc Magn Reson. 2010;12:59. [Open access.] PMID: 20977757, PMCID: PMC2984575.
The resting mid left ventricular short-axis slices of dobutamine stress cardiac magnetic resonance images (CMRIs) demonstrate no perfusion abnormalities in the left image, whereas the right image reveals perfusion abnormalities in the inferior (red arrow) and anterolateral (yellow arrow) regions of the left ventricle.
Physiologic challenges in elderly patients
Understanding the physiology of geriatric patients can aid clinicians in mitigating potential problems with airway management in these patients. For example, the cardiopulmonary system demonstrates its age during stress, such as during intubation. In elderly patients, the arteries become more stiff and myocardial compliance decreases with age, which results in left ventricular hypertrophy and diastolic failure.[4]
Images courtesy of Charoenpanichkit C, Hundley WG. J Cardiovasc Magn Reson. 2010;12:59. [Open access.] PMID: 20977757, PMCID: PMC2984575.
The barium esophagram on the left displays a dilated esophagus with a retained column of barium and "bird beaking" that is suggestive of achalasia; the barium esophagram on the right depicts end-stage achalasia with retained food and barium as well as a tortuous esophagus.
Elderly patients are particularly sensitive to laryngeal manipulation during airway management and may experience unpredictable swings in blood pressure and heart rate.[4] These sudden changes are more likely to induce myocardial ischemia and pulmonary edema in this population.[4] In addition, reduced chest wall compliance, smaller airways, and decreased diffusion capacity occur with aging, thereby limiting gas exchange and increasing airway resistance, which results in a greater likelihood of hypoxia and air trapping.[4,5]
Physiologic systems other than the cardiopulmonary system also affect geriatric airway management. As the body ages, esophageal motility decreases and peristalsis is slower and weaker; these, in turn, raise the risk of aspiration and subsequent ventilatory difficulty or, potentially, pneumonitis or pneumonia.[4]
Images courtesy of Patel DA, Kim HP, Zifodya JS, Vaezi MF. Orphanet J Rare Dis. 2015;10:89. [Open access.] PMID: 26198208, PMCID: PMC4509143.
The coronal brain MRIs show the difference between a healthy brain (left) and a brain in a patient with Alzheimer disease (right). The brain depicting Alzheimer disease exhibits severe atrophy of the cerebral cortex (i), severely enlarged ventricles (ii), and extreme shrinkage of the hippocampus (iii).
Cognitive impairment, common in the elderly, may interfere with patient compliance during an awake intubation.[4] In addition, many of the anesthetic agents used for intubation are associated with a higher risk of delirium. Delirium has been shown to significantly increase morbidity and mortality in the geriatric population.[4]
Seniors also frequently have preexisting chronic kidney disease,[6] which can cause a hypertensive response during intubation.[4] This hypertensive response may result in an acute kidney injury, pulmonary edema, or heart failure.
Images courtesy of Zhang Y, Dong Z, Phillips P, et al. Front Comput Neurosci. 2015;9:66. [Open access.] PMID: 26082713, PMCID: PMC4451357.
These computed tomography (CT) scans are from the same patient with recurrent rhinosporidiosis discussed in slide 1. The coronal (left) and sagittal (right) slices reveal extension of the tumor in the nasopharynx and oropharynx.
Anatomic challenges in elderly patients
The nasal and oral cavities also change with aging and may present unique challenges to intubation.[4] An increased incidence of nasal polyps may impede nasopharyngeal airway placement or nasal intubation. Loose teeth pose a choking hazard if displaced, and a lack of teeth significantly increases the difficulty of preintubation mask ventilation. In addition, the dry, frail lips of an elderly person are more likely to tear during an intubation attempt, and the reduced elasticity of the skin around the mouth and the weakening of perioral musculature makes bag-valve-mask ventilation more technically challenging.[4]
In the oropharynx, the presence of tumors or scars from previous removal(s) of neoplasms may obscure identifying anatomic landmarks (eg, vocal cords).[4] Moreover, once identified, the epiglottis of a geriatric patient is often more difficult to manipulate, in part related to delayed functioning, limited movement, or lack of downward movement.[4]
Images courtesy of Khan I, Gogia S, Agarwal A, Swaroop A. Case Rep Otolaryngol. 2014;2014:609784. [Open access.] PMID: 25574413, PMCID: PMC4276699.
The photograph shows a large cervical multinodular goiter.
Proper positioning for intubation often requires manipulation of the patient's neck. Elderly patients are more likely to have C-spine pathology, such as arthritis or osteophytes, thyroid masses, or previous neck surgery, all of which affect the neck's range of motion and ability to be optimally positioned.
Image courtesy of Berri T, Houari R. Pan Afr Med J. 2013;16:138. [Open access.] PMID: 24847400, PMCID: PMC4024433.
The neck radiograph reveals a dental bridge lodged in the pharygolarynx (arrow). On video-assisted laryngoscopy, the partial denture was seen to almost completely cover the vocal cords, and its clasps pierced the pharyngeal wall.
Optimizing the geriatric intubation
Preintubation optimization of all patients' respiratory status is critical to successful intubation and ventilation. If time allows, reversible conditions should be addressed and potential challenges should be evaluated.[4] For example, while the medical team prepares for the intubation, clinicians may administer bronchodilators to a patient with airway obstruction, start antibiotics in a patient with a respiratory infection, and/or remove any dentures because they pose a risk of obstructing the airway.[4] Clinicians should consider the use of a Miller blade (a straight laryngoscopy blade) to mitigate a large, floppy epiglottis.
Image courtesy of Hidaka H, Suzuki T, Toyama H, Kurosawa S, Nomura K, Katori Y. Head Face Med. 2014;10:23. [Open access.] PMID: 24919781, PMCID: PMC4059481.
This image capture of a videolaryngoscopic view shows the epiglottis uploaded (elevated) on the tip of the laryngosopy blade (arrow) in a straight blade technique. This technique is occasionally used to expose the vocal cords in patients with suboptimal glottic visualization.
To prevent unpredictable tachycardia during airway management, clinicians may consider the use of esmolol or a short-acting beta blocker.[4,7] For induction, particularly in a labile patient, etomidate may be more appropriate than propofol, as etomidate has been shown to be more hemodynamically stable. In a hypertensive patient, propofol may be considered; however, its blood pressure effects are difficult to predict and hypotension is a risk.[4,7]
If bag-valve-mask ventilation is unsuccessful because of a patient's anatomy, consider insertion of a laryngeal mask airway (LMA) while preparing for definitive airway management.[8]
Video laryngoscopy should be considered for all patients with an anticipated difficult airway undergoing intubation.[4,9] This procedure has a high success rate and is more gentle on fragile elderly lips and oral cavities.[4]
Image courtesy of Cavus E, Thee C, Moeller T, Kieckhaefer J, Doerges V, Wagner K. BMC Anesthesiol. 2011;11:6. [Open access.] PMID: 21362173, PMCID: PMC3060123.
Obese Patients
Morbidly obese patients pose another set of challenges to intubation and ventilation.[3,9] In one study of more than 12,400 patients, significantly more complications occurred during intubation in obese patients than in their average-sized counterparts, and these complications were more likely to lead to morbidity and mortality.[10]
Image courtesy of ASTIER / BSIP / Visuals Unlimited, Inc.
Illustrated and clinical examples of the modified Mallampati classification for oropharyngeal visualization are shown.
Preparing the airway of obese patients
If time permits prior to airway management, additional evaluations with the physical examination can aid clinicians in gauging the probable difficulty of the intubation. A Mallampati classification is obtained by inspecting the patient's pharynx and assessing their neck mobility; a higher classification indicates an increased risk for a more challenging intubation.[11]
One study demonstrated that the ratio of the neck circumference and thyromental distance (NC/TM) also improves predictions of a difficult laryngoscopy.[11] Obese patients with a large neck circumference as well as a short neck (NC/TM ratio ≥5.0) were more likely to have a challenging intubation.
Adapted images courtesy of (1) Medscape (illustrations) and (2) Huang HH, Lee MS, Shih YL, Chu HC, Huang TY, Hsieh TY. BMC Gastroenterol. 2011;11:12. [Open access.] PMID: 21324124, PMCID: PMC3045355 (clinical photographs).
An obese patient is undergoing video laryngoscopy in this photograph.
Anatomic challenges in obese patients
Many anatomic factors in overweight patients are associated with an increased level of difficulty for intubation, including the following[10,12]:
Image courtesy of Wikimedia Commons/DiverDave.
This patient has OSA and is connected to a continuous positive airway pressure (CPAP) machine via a nasal mask.
The increased incidence of OSA in obese patients raises the level of difficulty of airway management and subsequent ventilation.[8,12] These patients also have greater airway resistance, further compounding the decreased functional residual capacity and reduced lung compliance caused by their weight.[12]
Patients with a history of OSA should be positioned in reverse Trendelenburg to decrease the pressure on the posterior pharynx and to improve airway patency.[8,12] Prior to intubating a patient with OSA, consider providing CPAP for preoxygenation.[4,7-9]
Image courtesy of Wikimedia Commons/Halicki.
The image shows a CPAP mask hooked up to its air hose.
Optimizing the intubation in obese patients
Obesity also creates challenges to bag-valve-mask ventilation. Although bariatric patients should be preoxygenated prior to intubation, it is important for clinicians to be aware that preoxygenation is less effective in this population.[7,8]
If feasible, providing CPAP may improve the success of preoxygenation.[7] An oropharyngeal airway should be inserted prior to bag-valve-mask ventilation and, if staffing is available, the two-provider technique should be used, in which one person holds the mask with both hands and the other person ventilates the patient.[8,13]
Image courtesy of Wikimedia Commons/Joe Mabel.
The jaw-thrust maneuver to open the airway and improve ventilation is illustrated.
Positioning of obese patients
Obese patients should be positioned with the head-tilt/chin-lift and jaw-thrust maneuvers.[7,8] Although the fat pad on the patient's posterior neck may prove troublesome in the performance of these maneuvers, the techniques should still be attempted.
Adapted image courtesy of Wikimedia Commons/Bruce Blaus.
Obese patients have a reduced oxygen reserve and an increased rate of oxygen consumption.[14] Furthermore, the supine position decreases the functional residual capacity of their lungs—raising the risk of hypoxia during intubation—and the weight of their chest wall reduces lung compliance.[14] In addition, obese patients are at high risk for aspiration during intubation due to excess weight on the diaphragm from displacement of abdominal contents into the thoracic cavity. A reverse Trendelenburg position helps to improve these situations.[8,9,14,15] Preoxygenation should be considered if the patient is a candidate.
Bag-valve mask ventilation also increases the risk of aspiration and apnea in obese patients, because proper positioning for optimal ventilation may be difficult to achieve. The use of several folded blankets, elevation pillows, or a "ramp" beneath the head, shoulders, and upper body may aid in optimal positioning (see the next slide).[9,14,15]
Image by Sam Shlomo Spaeth for Medscape.
A diagrammatic representation of the appropriate positioning of an obese patient for intubation is shown.
Obese patients should be positioned with a ramp to align their ears with their sternal notch.[9,14,15] Blankets, pillows, or foam blocks may also be used to achieve this position, which is different from the sniffing position recommended for average-sized patients. The "ramped" position not only helps to improve the view on direct laryngoscopy, it also increases the success of bag-valve-mask ventilation.[9,14,15]
As noted earlier, obese patients, particularly the morbidly obese, are at high risk for aspiration. A reverse Trendelenburg position reduces the force pushing on the diaphragm and lowers the risk of aspiration.
Video laryngoscopy should be considered in all obese patients because it improves visualization of the airway.[15]
Image by Sam Shlomo Spaeth for Medscape.
The patient shown was a candidate for cricothyrotomy owing to the presence of the following: morbid obesity, pendulous overhanging tissue, and challenging neck anatomy (no neck and thyroid cartilage positioned in the sternal notch).
Surgical airway in obese patients
Cricothyrotomy is generally a last resort for patients who require an airway but who cannot be intubated or ventilated through any other means.[9,14] Following all the steps to optimize intubation in an obese patient should help avoid the need for a surgical airway. Nonetheless, a cricothyrotomy kit and a clinician experienced in performing this procedure should be readily available at the time of intubation.
This critical procedure is exceptionally challenging in obese patients.[9,13,14] Prior to cricothyrotomy, clinicians should expect to have difficulty identifying anatomic landmarks due to the presence of excess adipose tissue; therefore, they should prepare for a technically difficult surgical airway.[9,13,14]
Image courtesy of Rehm CG, Wanek SM, Gagnon EB, Pearson SK, Mullins RJ. Crit Care. 2002;6(6):531-5. [Open access.] PMID: 12493076, PMCID: PMC153438.
The presence of a steeple sign on this chest radiograph is indicative of croup.
Pediatric Patients
Children may require intubation for unique reasons, and pediatric intubation can create unique challenges to clinicians.
Young patients may present to the emergency department with stridor, an inspiratory sound indicative of a narrowed upper airway.[16] The differential diagnosis for stridor includes viral croup, bacterial tracheitis, and epiglottitis. The introduction of the Haemophilus influenza type B vaccine in the 1980s significantly reduced the incidence of epiglottitis, but this life-threatening condition still occurs, most commonly in children between the ages of 2 and 8 years.
A child with epiglottitis should be deemed to have an airway emergency; consider immediate intubation in the operating room.[16]
Image courtesy of Dr Kelly Marshall, CHOA at Scottish Rite.
On chest radiography, administration of a small amount of barium helped to reveal a swallowed radiolucent object (plastic guitar pick) in the upper esophagus of a child.
Children with foreign body airway obstruction may also present with stridor.[16] Even if the child does not have a known ingestion, clinicians should suspect foreign body ingestion or aspiration in the setting of a persistent cough or wheezing/stridor that does not improve with the use of bronchodilators.
Note that although many foreign bodies may not be visible on chest radiographs, obstructive emphysema and atelectasis may be seen.[16]
Image courtesy of Raymond K Tan, MD, and Gregory Conners, MD, MPH.
Intercostal muscle retractions in this infant demonstrate respiratory distress.
Physiologic challenges in pediatric patients
There are differences between the adult and pediatric cardiopulmonary systems.[17] Consider the following; compared to adults:
All of these factors put the infant at high risk for respiratory failure and make the infant a good candidate for early intervention.[17]
Image courtesy of Wikimedia Commons/Bob J Galindo.
The diagrams illustrate a child whose airway is not in the best position for intubation (left) and one whose airway is optimal for direct laryngoscopy with the aid of a towel (right).
Anatomic challenges in pediatric patients
Proper positioning plays a key role in the success of the pediatric intubation.[18] Children have a large occiput and a relatively short neck, posing a challenge for positioning their airway for optimal laryngoscopy. Thus, for children younger than 2 years, place a rolled towel under their shoulders to account for their large occiputs, thereby increasing extension of the head and improving opening of the airway.[18,19] For children older than 2 years, place them in the sniffing position.[18]
The anatomy of the pediatric airway also differs from that of the adult.[18] Unlike adults, whose airways are most narrow at the level of the vocal cords, the pediatric airway is narrowest at the cricoid ring. If clinicians encounter resistance of the endotracheal tube after its passage through the vocal cords, switching to a smaller endotracheal tube should be considered.[18]
Image by Sam Shlomo Spaeth for Medscape.
Straight-type Miller laryngoscopy blades are shown on the left; curved-type Macintosh laryngoscopy blades appear on the right.
Children have a larger tongue-to-mandible ratio than adults; thus, their tongues may obstruct the view of the larynx. Many children also have large tonsils and adenoids that prevent proper visualization of the glottic opening.[18] In addition, the epiglottis of young children are larger, floppier, and more curved than those of adults.
For these reasons, clinicians should consider using a straight laryngoscopy blade for pediatric intubation[17]—although studies proving its superiority to a curved blade are lacking.
An anterior airway in young children can also create a challenging laryngoscopy and produce an obstacle to placing the endotracheal tube; the risk of trauma to the anterior crux of the vocal folds from difficult insertion is increased.[17]
Images courtesy of Wikimedia Commons/DiverDave (left) and Wikipedia/Sasata (right).
The photograph shows a pediatric patient with Pierre Robin syndrome. Note the small lower jaw (arrow).
The highest prevalence of difficult pediatric intubations occurs in children who undergo cardiac or oral/maxillofacial surgery.[17] Consider the following[17]:
Photograph (left) courtesy of Sogaard M, Tumer Z, Hjalgrim H, et al. BMC Med Genet. 2005;6:21. [Open access.] PMID: 15904506, PMCID: PMC1174871. Illustration (right) by Sam Shlomo Spaeth for Medscape.
The photograph demonstrates the use of the Broselow Tape for determining appropriate pediatric endotracheal tube size.
Sizing of the endotracheal tube in pediatric patients
Proper endotracheal tube sizing is essential for intubating children. The appropriate tube size is printed on the Broselow Pediatric Emergency Tape ("Broselow Tape"), or it can be calculated.
If clinicians have difficulty intubating a child using the appropriate tube size, a second intubation attempt may be made with a smaller tube.[19] Cuffed endotracheal tubes are preferred in children older than 3 years, as these types of tubes improve ventilation and prevent aspiration. Cuffed tubes may be considered in younger children.[19]
Use of an endotracheal tube that is too large not only puts the patient at risk for an airway injury but also for intubation into the right mainstem bronchus.[19] However, an endotracheal tube that is too small can result in poor ventilation and/or an unplanned tube displacement. Therefore, multiple sizes of endotracheal tubes should always be readily available during an intubation.[20]
Image courtesy of Wikimedia Commons/Stkittschris.
An example of a pediatric LMA is depicted, with the adult fingers used for scale.
Ventilation of pediatric patients
Bag-valve-mask ventilation may be problematic in children owing to anatomic and/or physiologic challenges. If difficulty in ventilation is encountered, place an oropharyngeal airway and resume ventilation.[17]
Laryngospasm (more common in children), inadequate anesthesia, and poor positioning can also complicate bag-valve-mask ventilation in this population. If increased sedation and improved positioning do not resolve the issue, consider the use of a supraglottic airway (eg, an LMA) as a rescue airway.[8,16] However, avoid using an LMA in patients who have a full stomach, have suffered recent trauma, or have high ventilator requirements.[17] Note that although LMAs are very helpful as airway adjuncts, these airways can be misplaced, and they can cause local trauma to the airway.
Image courtesy of courtesy of Nicole Cimino-Fiallos, MD.
This child is undergoing repair of a cleft palate, which is a known risk factor for a difficult intubation.
Surgical airway in pediatric patients
If all airway maneuvers fail and a child is cannot to be intubated or ventilated, clinicians must consider establishing a surgical airway.
In patients older than 8 years, clinicians can proceed with the same cricothyrotomy procedure as that used in the adult population. However, in those younger than 8 years, anatomic changes in the positioning of the cricothyroid membrane and the hyoid bone make cricothyrotomy technically challenging; therefore, a needle cricothyrotomy in combination with jet ventilation is preferred in this age group.[19] Needle cricothyrotomy should be considered a temporizing measure; a definitive airway plan must be identified for these children.[19]
Image courtesy of United States Army/Specialist Nashaunda Tilghman.
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