Nasotracheal intubation over a bougie vs. non‐bougie intubation: a prospective randomised, controlled trial in older children and adults using videolaryngoscopy*
*Presented in part at the Society for Airway Management Annual Meeting, Atlanta, Georgia, USA, September 2016
*You can respond to this article at http://www.anaesthesiacorrespondence.com
video: click here.
Conventionally, nasotracheal intubation has consisted of blind nasal passage and external manipulation of the tube through the glottis (‘conventional technique’), a technique associated with a high incidence of nasal trauma. We evaluated a novel technique for routine asleep (i.e. post‐induction) nasotracheal intubation using a bougie (‘bougie technique’), which uses a nasopharyngeal airway to guide a paediatric bougie nasotracheally for use as a Seldinger tracheal intubation guide. Two hundred and fifty‐seven older children (> 8 years) and adults were randomly assigned to videolaryngoscopy‐assisted nasotracheal intubation using either the conventional or the bougie technique. The hypothesis was that the bougie technique would result in less nasopharyngeal trauma. The bougie technique was associated with significantly less nasopharyngeal bleeding than the conventional technique at both 60–90 s (55% vs. 68%; p = 0.033) and 5 min (51% vs. 70%; p = 0.002). The severity of bleeding was also significantly less with the bougie technique, with an OR for active bleeding of 0.42 (95%CI 0.20–0.87; p = 0.020) at 60–90 s and 0.15 (95%CI 0.06–0.37; p < 0.0001) at 5 min. Magill forceps were needed significantly less often with the bougie technique (9% vs. 28%, p = 0.0001) and there was no difference in first attempt and overall success rates between the two techniques (p = 0.133 and p = 0.750, respectively). Not only is nasal intubation over a bougie as successful as the conventional technique, it also significantly decreases both the incidence and severity of nasopharyngeal trauma, as well as the need for the use of Magill forceps.
Face-mask ventilation is considered a fundamental procedural skill in emergency medicine. We have historically deployed it when patients are apneic, are hypoventilating, or need assistance with oxygenation. We keep bag-mask units at the head of every bed in the emergency department.
The world of airway management has evolved since the self-inflating bag-valve mask (BVM) was first created more than 50 years ago. In elective anesthesia, the laryngeal mask airway (LMA) has entirely replaced face-mask ventilation as a strategy for airway and anesthetic management in cases with a low risk of aspiration. In fact, the laryngeal mask is now used in the majority of elective anesthesia cases worldwide. It also has a rapidly growing presence in the world of prehospital care, especially in the United Kingdom and Europe.
The tip of the laryngeal mask wedges into the upper esophagus, behind the cricoid cartilage. It provides a wedge-shaped “stopper” to the upper esophagus; it’s not quite as effective as a tracheal tube in isolating the trachea from the esophagus but is far better than pushing gas by face mask into the shared upper aero-digestive tract of the pharynx.
LMA-type devices have replaced intubation and mask ventilation in elective anesthesia because they are better for both patients and operators. The laryngeal mask “sits” itself around the curve of the tongue and stays in position. The face mask requires continued downward pressure on the mask to maintain a seal. It can also be augmented by compressive head straps. The laryngeal mask can be easily used to bag a patient with one hand stabilizing the top of the device and the other squeezing the bag. This is not the case with a face mask. Holding the mask against the face works poorly, even with an “E-C grip” (using first and seconds digits [“C”] to hold the nasal bridge of the mask and the third, fourth, and fifth digits [“E”] to hold the lower mask).
Face-mask ventilation is as ergonomically smooth as walking in ski boots. The mask seals by being pushed onto the face, but this motion also pushes the mandible, base of the tongue, and epiglottis downward. And particularly in supine patients with no muscular tone, the base of the tongue, epiglottis, and mandible fall backward, causing “collapse” of the airway. Without continuous active lifting of the angle of the mandible, the airway obstructs. Conversely, the laryngeal mask seal is achieved by the same soft tissues falling backward onto the bowl of the device. It is not the inflation of a cuff that creates a mucosal seal; the newest and best laryngeal masks have, in fact, no cuffs at all. They mirror the laryngeal anatomy.
The laryngeal mask is, in fact, the only gravity-enhanced ventilation device. Gravity and loss of tone defeat the face mask. Conversely, administration of propofol, which induces a deep loss of upper-airway tone, is far and away the most commonly used medication for laryngeal mask anesthesia. The loss of tone in a supine position is ideal for creating the laryngeal mask seal around the bowl of the device. The soft tissues of the upper airway (base of tongue, epiglottis, and perilaryngeal structures) collapse backward onto the bowl of the LMA as muscular tone about the mandible is abolished.
In addition to the ergonomic challenges of doing effective mask ventilation—trying to create a face seal while pressing against the face but pulling up on the mandible simultaneously—there are many physiologic reasons why mask ventilation in a flat position is bad for oxygenation and also why it has a high risk for regurgitation. As a face mask is squeezed over the mouth, the oropharynx gets pressurized (see Figure 1). The goal is to have air only go into the lungs as opposed to the collapsed esophagus. Unfortunately, as pressure increases, especially at about 20 cmHg, air will enter the esophagus and subsequently the stomach. This insufflation of the stomach then leads to regurgitation of stomach contents back up the esophagus to the perilaryngeal area of the hypopharynx (at the top of the esophagus). Regurgitation risk is dramatically increased by having the patient’s stomach and head on the same level or, in an obese patient, the stomach higher than the mouth when the patient is supine. As the stomach gets insufflated, gravity promotes regurgitation of stomach contents into the upper airway.
The LMA, in contradistinction to a face mask, provides some isolation of the esophagus and larynx. The tip of an LMA-type device wedges into the upper esophagus. It’s not a complete isolation like a cuffed tube in the trachea, but by “corking” the top of the esophagus, there is some protection from gas entering the esophagus. Additionally, the bowl of the LMA is sitting directly under the laryngeal inlet, so the amount of pressure needed to get oxygen into the lungs is less than what is used typically with a face mask, having to start from outside the mouth and flow around the tongue.
In addition to the ergonomic difficulties of face-mask ventilation, problems creating an effective seal, and issues delivering oxygen into the lungs at low pressure, mask ventilation in a supine position has many disadvantages in terms of oxygenation.
In a flat position, the abdominal contents push the diaphragm upward, reducing the functional residual capacity of the lungs. Additionally, the posterior lung segments collapse.
Unlike pressurization of the oropharynx, pressurization of the nasopharynx causes passive opening of the airway as the soft palate is pushed away from the posterior pharynx (see Figure 1). Combining nasal oxygen with pulling on the mandible is an incredibly easy and fast way to open the upper airway. Oxygen shoots from the nasopharynx, down into the upper airway, and into the trachea. In the patient who is upright, the diaphragm drops and the lungs expand. Through the miracle of hemoglobin, oxygen is drawn down the trachea as it gets absorbed across the alveolar capillary membrane even without positive pressure ventilation (apneic oxygenation).
I used to bag patients as my initial response to hypoxemia in the emergency setting. Now, I put Oxygen On, Pull on the mandible, and Sit the patient up (OOPS). I have done this in the setting of oversedation and narcotic overdose, which resulted in complete apnea, and oxygenation improves quickly. I sometimes augment nasal oxygen at the top of the flow meter 15+ liters with a non-rebreather to boost oxygen flow >30 lpm.
In cardiac arrest, I used to bag patients while preparing to intubate. Now, I use passive apneic oxygenation and, if necessary, place an LMA-type device to run the initial portion of the code.
My current use of mask ventilation is only when I want to deliver some positive end-expiratory pressure (PEEP; PEEP valves should be on every BVM). This is generally only used when inducing patients for intubation. I gently ventilate for a couple of breaths when I use muscle relaxants to confirm that I can bag the patient and to expand the alveoli during the onset phase of muscle relaxants. I always do so in a head-elevated position (at least ear-to-sternal notch). I am careful to use low pressure, low volumes, and low rates, except in situations of compensatory respiratory alkalosis. My use of face-mask ventilation in these settings is generally with a nasal cannula, which helps stent the airway open and augment flow. I choose to perform face-mask ventilation in this situation, as opposed to an LMA, because I am worried about the LMA device being inserted too early, which could trigger active vomiting before rapid-sequence intubation medications kick in.
The role of face-mask ventilation in emergency situations is rapidly diminishing. I believe the first response to hypoxia should always be Os up the nose, either a standard nasal cannula combined with a non-rebreather to get flows >30 lpm or special high-flow, warm, humidified nasal cannula systems. Sit the patient upright as much as possible and pull on the mandible. In cardiac arrest, passive oxygenation and an LMA-type device should be used preferentially over bagging a patient in a flat position. If you have to use a face mask to provide PEEP (ie, BVM with a PEEP valve or continuous positive airway pressure mask), always do so in an upright position.
ACEP Now – http://www.acepnow.com/article/emergency-physicians-abandon-face-mask-ventilation/
Ease and difficulty of pre-hospital airway management in 425 paediatric patients treated by a helicopter emergency medical service: a retrospective analysis.
Pre-hospital paediatric airway management is complex. A variety of pitfalls need prompt response to establish and maintain adequate ventilation and oxygenation. Anatomical disparity render laryngoscopy different compared to the adult. The correct choice of endotracheal tube size and depth of insertion is not trivial and often challenged due to the initially unknown age of child.
Data from 425 paediatric patients (<17 years of age) with any airway manipulation treated by a Swiss Air-Ambulance crew between June 2010 and December 2013 were retrospectively analysed. Endpoints were: 1) Endotracheal intubation success rate and incidence of difficult airway management in primary missions. 2) Correlation of endotracheal tube size and depth of insertion with patient’s age in all (primary and secondary) missions.
In primary missions, the first laryngoscopy-guided endotracheal intubation attempt was successful in 95.3% of cases, with an overall success rate of 98.6%. Difficult airway management was reported in 10 (4.7%) patients. Endotracheal tube size was frequently chosen inadequately large (overall 50 of 343 patients: 14.6%), especially and statistically significant in the age group below 1 year (19 of 33 patients; p < 0.001). Tubes were frequently and distinctively more deeply inserted (38.9%) than recommended by current formulae.
Difficult airway management, including cannot intubate and cannot ventilate situations during pre-hospital paediatric emergency treatment was rare. In contrast, the success rate of endotracheal intubation at the first attempt was very high. High numbers of inadequate endotracheal tube size and deep placement according to patient age require further analysis. Practical algorithms need to be found to prevent potentially harmful treatment.
PS Releases Exhaustive Guidelines for Post-Op PainThe American Pain Society (APS) has released comprehensive new guidelines for pain management following surgery. Studies have shown that a majority of patients who undergo surgery report inadequate postoperative pain relief, which could affect their quality of life and increase their risk for postsurgical complications and persistent pain, according to the APS. “The intent of the guideline is to provide evidence-based recommendations for better management of postoperative pain, and the target audience is all clinicians who manage pain resulting from surgery,” said Roger Chou, MD, lead author and head of the Oregon Evidence-based Practice Center, in a press release.
The evidence-based guidelines contain 32 recommendations for clinicians and supports the use of a multimodal approach to pain management, which includes a variety of analgesic medications and techniques and non-pharmacologic interventions.The guidelines were developed by a multidisciplinary expert panel on management of postoperative pain. The guidelines are published in The Journal of Pain (2016;17(2):131-157).
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Endotracheal intubation remains the standard of care when definitive control of the airway is required.1 Unlike intubation in elective anesthesia, patients in an emergency department requiring airway access are assumed to have a full stomach and are therefore at risk for aspiration during intubation.2
In these patients, laryngoscopy itself may cause fluids from the esophagus to flood the pharyngeal cavity.1 Indeed, pulmonary aspiration occurs in 4% to 20% of all emergency intubations.3,4 This is especially a risk in patients with acute epistaxis, gastrointestinal bleeding, or a history of airway trauma.5-7
Aspiration of as little as one fourth of a mouthful (0.4 mL/kg) of stomach contents may cause severe pulmonary injury or even death.8 Moreover, the presence of oropharyngeal fluids in the airway obstructs the view of the vocal cords, resulting in repeated and often unsuccessful attempts at direct visualization of the larynx, interrupted by urgent suctioning of the oropharynx. Attempts at mask ventilation to maintain oxygenation may force fluids and particles into the lung. Standard airway management algorithms deal with this scenario in a cursory manner or not at all.9,10
Defaulting to the emergency establishment of surgical airway through a cricothyroidotomy—a procedure not practiced commonly by many emergency physicians—may also not be a suitable alternative. Even with successful cricothyroidotomy, air leaks from the larynx may prevent adequate lung ventilation. A cricothyroidotomy airway does not protect the lungs from aspiration of blood, airway secretions and stomach contents. There may not be any alternative but to deal with the massive fluid accumulation.
In this manuscript, we present 4 maneuvers to resolve the problem of rapid fluid accumulations in the pharynx obscuring laryngeal visualization. We expect that at least some of these methods are known to many critical care workers, but we suspect that few know them all. Indeed, we did not find them in our review of the published literature and standard textbooks. Our aim is to present the methods together to enlarge the repertoire of front-line health care workers in managing heavy secretion loads during attempts at airway access.
Murphy Eye Suction
The Murphy “eye” is a port at the distal end of an endotracheal tube (ETT) that was historically intended to provide right upper lobe lung ventilation in the case of inadvertent right main bronchus intubation. Although this port is unlikely to provide any benefit for its intended use, it can be used to hold a tracheal suction catheter while an assistant occludes the catheter’s bypass port to provide suction at the tip (Figures 1 and 2). The ETT is then used as a wand to direct the suction ports of the suction catheter. When the larynx is in clear view, the suction tip can be passed through the larynx and act as a guide for the ETT. The tracheal suction catheter can then be withdrawn before the ETT cuff is inflated. Alternatively, when there is good visualization, an assistant can withdraw the suction catheter immediately prior to passing the ETT through the laryngeal opening.
ETT as a Suction Wand
Should fluid accumulation exceed the suctioning capacity of the tracheal catheter or contain suspended solid food particles and/or clots, the ETT itself can be turned into a suction wand by attaching its proximal end directly to the suction tubing (Figure 2 and Appendix). Note that there is no suction applied to the lung when the ETT is in the trachea if the proximal hole is not occluded. If tracheal suction is required, it should be performed with a tracheal suction catheter passed down the ETT to avoid atelectasis and lung damage.
It may be difficult to decide on optimal patient positioning during laryngoscopy. Head-up tilt may reduce fluid being regurgitated from the stomach. The disadvantage of this position is that fluid coming from the nasopharynx or mouth will pool in the pharynx. Very little accumulation of fluid is required to obstruct the view of the larynx. Furthermore, if the operator is standing at the head of the bed, it is much more difficult to view the larynx during laryngoscopy if the head of the patient’s bed is tilted up.
Consider instead tilting the patient’s head down. Until the nasopharynx is filled with fluid, the air-fluid level will be in the nasopharynx, leaving the larynx exposed, and reducing the risk for aspiration. If there are no contraindications (such as craniofacial trauma11), one can additionally pass a nasopharyngeal airway and attach suction tubing with a hole cut in the distal portion of the tubing to provide continuous drainage (Figure 3). The tip of the nasopharyngeal airway can remain in the nasopharynx during attempts at laryngeal intubation, as it does not obscure the view of the larynx or obstruct the advancement of the ETT. Continuous suction at the level of the pharynx may allow continued visualization of the larynx with less head-down tilt.
The “Blind” Advance
The fourth strategy is most suitable if the source of the fluid is the gastrointestinal tract, especially in the presence of a large amount of particulate material in the pharynx. In this case, the ETT is advanced blindly and the cuff is inflated (Figure 4). A suction catheter is then passed down the ETT and aspirated. If air is aspirated (confirming that the ETT is in the trachea), then after suitable airway toilet, the patient may be ventilated by applying positive pressure to the self-inflating bag. If gastric fluid is aspirated, or if the catheter tip becomes occluded (indicating that the esophagus has collapsed around the suction catheter openings), then:
- a piece of tape is placed over the ETT connector, occluding the lumen of the tube;
- the ETT is advanced so that the ETT connector is flush with the mouth;
- the cuff is inflated with at least 10 cc of air;
- the pharynx is suctioned thoroughly;
- the patient is ventilated by applying positive airway pressure to the face mask with a self-inflating bag; and
- position is confirmed by listening for air entry in the lungs and over the stomach.
Once the patient is adequately ventilated, then:
- a gastric tube is passed through the ETT to decompress the stomach; and
- the ETT is left in place to prevent regurgitation of stomach contents.
This optimizes the conditions for a second attempt at endotracheal intubation using a direct or indirect method.
The 4 methods that we describe are designed to supplement the standard repertoire of methods of managing difficult airways and potentially circumvent the need for a surgical airway. Passing the tracheal suction catheter through the Murphy eye is certainly the fastest to implement. Its major limitation, however, is the diameter of the suction tubing, which limits the rate of fluid aspiration.
Using the ETT itself as a suction wand provides a larger bore for aspiration in the presence of massive pharyngeal flooding from the stomach, large particles such as food, or viscous mucous secretions12 that tend to clog even the standard Yankauer suction wand. Moreover, by modifying the ETT such that it also acts as a suction device, the clinician is able to maintain constant visualization of the vocal cords while advancing an ETT.
Placing the patient in a steep head-down tilt reduces pooling at the larynx and may also decrease the likelihood of aspiration of fluid. Its major limitations are that it may not be useful for viscous secretions, and head-down tilt makes the operator position for laryngoscopy more awkward.
Finally, the improvised combined airway can actually be a first-line approach with massive flooding of the airway, especially with vomit. The ventilation approach is similar in concept to several commercially available double-lumen endoesophageal tubes (Combitube).
A major concern during all emergency endotracheal intubations is the risk for aspiration of fluids or particulate matter into the lungs. In a study examining the incidence of cardiac arrest during emergency intubations, it was found that 83% of cases were associated with profound hypoxemia (oxygen saturation <70%) during the airway procedure,13 which is likely to occur with fluid aspiration after multiple failed intubation attempts. The airway maneuvers presented here may be considered in all emergency patients who are at risk for fluid aspiration, as the time taken to switch between an ETT and a suction wand may be the determining factor for the success of laryngeal intubation or the extent of aspiration.
While clearly these are improvised methods that require some time to assemble, they can be prospectively assembled and placed on designated airway carts throughout the emergency department to allow their use when needed, with minimal disruption.
In summary, we present 4 airway maneuvers intended to help manage fluid accumulations in the pharynx during attempts at endotracheal intubation. Our intention is to increase the repertoire of techniques for managing difficult airways of front-line health care workers in the emergency department.
- Kabrhel C, Thomsen TW, Setnik GS, et al. Videos in clinical medicine. Orotracheal intubation. N Engl J Med. 2007;356(17):e15.
- Taryle DA, Chandler JE, Good JT Jr, et al. Emergency room intubations—complications and survival. Chest. 1979;75(5):541-543.
- Oswalt JL, Hedges JR, Soifer BE, et al. Analysis of trauma intubations. Am J Emerg Med. 1992;10(6):511-514.
- Thibodeau LG, Verdile VP, Bartfield JM. Incidence of aspiration after urgent intubation. Am J Emerg Med. 1997;15(6):562-565.
- Viducich RA, Blanda MP, Gerson LW. Posterior epistaxis: clinical features and acute complications. Ann Emerg Med. 1995;25(5):592-596.
- Perry M, Dancey A, Mireskandari K, et al. Emergency care in facial trauma—a maxillofacial and ophthalmic perspective. Injury. 2005;36(8):875-896.
- Carducci B, Lowe RA, Dalsey W. Penetrating neck trauma: consensus and controversies. Ann Emerg Med. 1986;15(2):208-215.
- DePaso WJ. Aspiration pneumonia. Clin Chest Med. 1991;12(2):269-284.
- Practice guidelines for management of the difficult airway: an updated report by the American Society of Anesthesiologists Task Force on Management of the Difficult Airway. Anesthesiology. 2003;98(5):1269-1277.
- Walls RM. The emergency airway algorithms. In: Walls RM, Murphy MF, Luten R, eds. Manual of Emergency Airway Management. 2nd ed. Philadelphia, PA: Lippincott Williams and Wilkins; 2004.
- Ellis DY, Lambert C, Shirley P. Intracranial placement of nasopharyngeal airways: is it all that rare? Emerg Med J. 2006;23(8):661.
- Vandenberg JT, Lutz RH, Vinson DR. Large-diameter suction system reduces oropharyngeal evacuation time. J Emerg Med. 1999;17(6):941-944.
- Mort TC. The incidence and risk factors for cardiac arrest during emergency tracheal intubation: a justification for incorporating the ASA Guidelines in the remote location. J Clin Anesth. 2004;16(7):508-516.
Literature and Discussion:
Many injuries sustained during anaesthesia are due to human error and may be avoided through high standards of clinical practice. Ocular injury occurs during 0.1- 0.5 % of general anaesthetics when eyes are taped and is usually corneal in nature1,2. This incidence has been reported at 44% in one study of untaped eyes during general anaesthesia3.Eye injuries account for 2% of medico-legal claims against anaesthetists in Australia and United Kingdom1,3 and 3% in the USA4.
Affect of General Anaesthesia on Eyes
General anaesthesia reduces the tonic contraction of the orbicularis oculi muscle, causing lagophthalmos ie. the eyelids do not close fully in 60% of patients1.
In addition, general anaesthesia reduces tear production and tear-film stability, resulting in corneal epithelial drying and reduced lysosomal protection. The protection afforded by Bell’s phenomenon (in which the eyeball turns upwards during sleep, protecting the cornea) is also lost during general anaesthesia5.
Mechanism of Injury
Corneal abrasions are the most common injury; they are caused by direct trauma, exposure keratopathy3,6,7or chemical injury6,8.
An open eye increases the vulnerability of the cornea to direct trauma from objects such as face masks, laryngoscopes, identification badges, stethoscopes, surgical instruments, anaesthetic circuits, or drapes.
Exposure keratopathy refers to the drying of the cornea with subsequent epithelial breakdown9. When the cornea dries out it may stick to the eyelid and cause an abrasion when the eye reopens10.
Chemical injury can occur if cleaning solutions such as Betadine, chlorhexidine or alcohol are inadvertently spilt into the eye, such as when the face or mouth is being prepped for surgery2,3.
Therefore, the anaesthetist must ensure that the eyes are fully closed and remain closed throughout the procedure, in order to avoid exposure keratopathy. Seemingly trivial contact can result in corneal abrasion and the risk of this occurring is markedly increased if exposure keratopathy is already present3.
Corneal abrasions can be excruciatingly painful in the postoperative period, may hamper postoperative rehabilitation and may require ongoing ophthalmological review and after care. In extreme cases there may be partial or complete visual loss.
Methods to Prevent Eye Injuries
Methods to prevent perioperative corneal injuries include simple manual closure of the eyelids, taping the eyelids shut, use of eye ointment (although this is controversial, see below), bio-occlusive dressings and suture tarsorrhaphy. However, none of the protective strategies are completely effective; vigilance is always required ie. the eyes need to be inspected regularly throughout surgery to check they are closed1.
Problems with current methods
For many years, in most western countries, the eyes of patients undergoing general anaesthesia have been routinely taped or stuck down with adhesive dressings in an attempt to combat these problems.
Unfortunately many of the adhesives used on medical products today are temperature and time sensitive ie. their adhesive strength may increase or decrease when applied to a 37 degree Celsius body11 and the longer they are applied, the greater the variability in their adhesiveness. What may seem the perfect adhesive strength before application can change as the operation progresses; leading to failure of stick or “over stickiness”. In the former case, the eyelids may move apart and in the latter, may cause bruising, eyelid tears and eyelash removal.
Rolls of tapes are often “laying around” the operating theatre and may not be hygienically clean12. Most of these tapes are translucent and so it is not possible to see if the patient’s eyes are opened or closed throughout the case. It is not uncommon for the eyelids to move open as the case progresses, even with adhesive tapes stuck onto them.
In a practical sense, these medical tapes/dressings may be difficult to remove from a patient because their ends can become stuck flush with the skin.
As noted above, there have been several studies looking at the efficacy and safety of eye ointments/lubricants as adjuncts with tape or as a stand-alone management for intra-operative eye closure. Unfortunately many in common use have problems. Petroleum gel is flammable and is best avoided when electrocautery and open oxygen are to be used around the face. Preservative-free eye ointment is preferred, as preservative can cause corneal epithelial sloughing and conjunctival hyperemia8; they have been implicated in blurred vision in up to 75% of patients.
They do not protect from direct trauma5,13.
Adverse Outcomes Associated With Intra-operative Injuries
|Increased length of stay.||Due to ophthalmology consults required, associated infections and treatment13|
|Increased costs.||Due to increased length of stay, cost of treating the complications14|
|Pain and discomfort for patient.||Corneal abrasions are extremely painful for the patient and the treatment consists of drops and ointments applied in the eye which may cause discomfort for the patient13,14|
The University of Texas Medical School at Houston
Director of Advanced Airway Management
Memorial Hermann Hospital–Texas Medical Center
Executive Director 2009-Present, Society for Airway Management
Dr. Hagberg has received grant support from Ambu, Karl Storz Endoscopy, Mallinckrodt, and MedcomFlow, and is also an unpaid consultant for Ambu, Covidien, and SonarMed.
Editor’s note: All acronyms are listed on page 28.
Management of the difficult airway remains one of the most relevant and challenging tasks for anesthesia care providers. This review focuses on several of the alternative airway management devices/techniques and their clinical applications, with particular emphasis on the difficult or failed airway. It includes descriptions of many new airway devices, several of which have been included in the ASA Difficult Airway Algorithm.1
Alternative Airway Devices
A common factor preventing successful tracheal intubation is the inability to visualize the vocal cords during the performance of DL. Many devices and techniques are now available to circumvent the problems typically encountered with a difficult airway using conventional DL.
Endotracheal Tube Guides
Several ET guides have been used to aid in intubation or extubation, including both reusable/disposable and solid/hollow introducers, stylets, and tube exchangers (Table 1).
In the past decade, many lighted stylets have been developed, including light wands, which rely on transillumination of the tissues of the anterior neck to demonstrate the location of the tip of the ET—a blind technique, unless combined with DL, and visual scopes, which use fiber-optic imagery and allow indirect visualization of the airway. They also can be used alone or in conjunction with DL (Table 2).
Viewing stylets provide a view from the tip of the ET. Whereas the view from a VL is at the end of the laryngoscope, viewing stylets provide a view from the tip of the ET for steering the ET through the cords. The stylet size for this device allows it to be placed within an ET as an independent instrument, or as an adjunct to VL or DL. Additionally, some can be used to place an ET through intubating supraglottic ventilatory devices for visualization of ET placement through the SGA (Table 2).
Video-assisted techniques have become pervasive in various surgical disciplines, as well as in anesthesiology. As more VLs are introduced into clinical practice, and as airway managers become more skillful with the technique of video-assisted laryngoscopy, it could well become standard procedure for patients with known or suspected difficult airways. It also may become the standard for routine intubations as the equipment and users’ skills improve and the cost of the devices decreases, with the potential for important savings in time and decreased morbidity in patients. It is beyond the scope of this review to discuss all of the laryngoscopes that have been manufactured; thus, only some of the most recently developed blades will be described (Table 3).
Indirect Rigid Fiber-Optic Laryngoscopes
These laryngoscopes were designed to facilitate tracheal intubation in the same population that would be considered for flexible fiber-optic bronchoscopy, such as patients with limited mouth opening or neck movement. Relative to the flexible FOBs, they are more rugged in design, control soft tissue better, allow for better management of secretions, are more portable (with the exception of the new portable FOBs), and are not as costly. Intubation can be performed via the nasal or oral route and can be accomplished in awake or anesthetized patients (Table 4).
Supraglottic Ventilatory Devices
The Laryngeal Mask Airway (Teleflex) is the single most important development in airway devices in the past 25 years. Since its introduction into clinical practice, it has been used in more than 300 million patients worldwide. Other supraglottic ventilatory devices are available for routine or rescue situations. The most recently developed supraglottic ventilatory devices have a gastric channel or are intended to be used as a conduit for fiber-optic–guided intubation (Table 5).
Special Airway Techniques
For managing patients in whom a difficult airway is suspected or anticipated, securing the airway before induction of general anesthesia adds to the safety of anesthesia and helps minimize the possibility of major complications, including hypoxic brain damage and death. To perform awake intubation, the patient must be adequately prepared for the procedure. Good topical anesthesia is essential to obtund airway reflexes and can be provided by various topical agents and administrative devices (Table 6). Other relatively new devices can be used to best position patients and maintain an open airway during awake intubation (Table 7).
Atomizing devices currently available for delivering topical anesthesia to nasal, oral, pharyngeal, laryngeal, and tracheal tissues include the DeVilbiss Model 15 Medical Atomizer (DeVilbiss Healthcare), the Enk Fiberoptic Atomizer Set (Cook Medical), the LMA MADgic Laryngo-Tracheal Atomizer (Teleflex), and the LMA MADgic Airway (Teleflex). Although any technique of tracheal intubation can be performed under topical anesthesia, flexible fiber-optic intubation is most commonly used.
Flexible Fiber-Optic Intubation
Flexible fiber-optic intubation is a very reliable approach to difficult airway management and assessment. It has a more universal application than any other technique. It can be used orally or nasally for both upper and lower airway problems and when access to the airway is limited, as well as in patients of any age and in any position. Technological advances—including improved optics, battery-powered light sources, better aspiration capabilities, increased angulation capabilities, and improved reprocessing procedures—have been developed. The Airway Mobilescope (MAF; Olympus) is a portable, flexible endoscope with expanded viewing and recording capability, incorporating a monitor, LED light source, battery, and recording device in a single unit. A completely disposable system, the aScope (Ambu) also is available. Rescue techniques, such as DL and placing a retrograde guidewire through the suction channel, may be performed if the glottic opening cannot be located with the scope, or if blood or secretions are present. Insufflation of oxygen or jet ventilation through the suction channel may provide oxygen throughout the procedure, and allow additional time when difficulty arises in passing the ET into the trachea.
Retrograde intubation (Table 6) is an excellent technique for securing a difficult airway either alone or in conjunction with other airway techniques. Every anesthesia care provider should be skilled in employing this simple, straightforward technique. It is especially useful in patients with limited neck mobility that is associated with cervical spine pathology or in those who have suffered airway trauma. Cook Medical has 2 retrograde intubation sets: a 6.0 Fr for placing tubes of ≥2.5 mm ID, and a 14.0 Fr for placing tubes of ≥5.0 mm ID.
Transtracheal Jet Ventilation
TTJV is a well-accepted method for securing ventilation in rigid and interventional bronchoscopy, and there are several commercial manual jet ventilation devices available (Table 6). The Enk Oxygen Flow Modulator (Cook Medical) is recommended for use when jet ventilation is appropriate but not available. An MRI Conditional 3.0 Tesla manual jet ventilator (Anesthesia Associates, AincA) is also now available to enable TTJV in the MRI suite for both planned and emergency procedures (Table 6).
Cricothyrotomy (Table 8), a lifesaving procedure, is the final option for “cannot-intubate, cannot-ventilate” patients according to all airway algorithms, whether they concern prehospital, ED, ICU, or surgical patients. In adults, needle cricothyrotomy should be performed with catheters at ≥4 cm and ≤14 cm in length. A 6.0 Fr reinforced fluorinated ethylene propylene Emergency Transtracheal Airway Catheter (Cook Medical) has been designed as a kink-resistant catheter for this purpose. Percutaneous cricothyrotomy involves using the Seldinger technique to gain access to the cricothyroid membrane. Subsequent dilation of the tract permits passage of the emergency airway catheter. Surgical cricothyrotomy is performed by making incisions through the cricothyroid membrane using a scalpel, followed by the insertion of an ET. This is the most rapid technique and should be used when equipment for the less-invasive techniques is unavailable and speed is particularly important.
Tracheostomy (Table 9) establishes transcutaneous access to the trachea below the level of the cricoid cartilage. Emergency tracheostomy may be necessary when acute airway loss occurs in children under the age of 10 or those whose cricothyroid space is considered too small for cannulation, as well as in individuals whose laryngeal anatomy has been distorted by the presence of pathologic lesions or infection.
Percutaneous dilatational tracheostomy is the most commonly performed tracheostomy technique, yet it is still considered invasive and can cause trauma to the tracheal wall. Translaryngeal tracheostomy, a newer tracheostomy technique, is considered safe and cost-effective, and can be performed at the bedside. It may be beneficial in patients who are coagulopathic. Surgical tracheostomy is more invasive, and should be performed on an elective basis and in a sterile environment.
Most airway problems can be solved with relatively simple devices and techniques, but clinical judgment born of experience is crucial to their application. As with any intubation technique, practice and routine use will improve performance and may reduce the likelihood of complications. Each airway device has unique properties that may be advantageous in certain situations, yet limiting in others. Specific airway management techniques are greatly influenced by individual disease and anatomy, and successful management may require combinations of devices and techniques.
- ASA Difficult Airway Algorithm. Anesthesiology. 2013;118:251-270
- American Society of Anesthesiologists Task Force on Management of the Difficult Airway. Practice guidelines for management of the difficult airway: an updated report by the American Society of Anesthesiologists Task Force on Management of the Difficult Airway. Anesthesiology. 2003;98(5):1269-1277.
- Miller CG. Management of the difficult intubation in closed malpractice claims. ASA Newsletter. 2000;64(6):13-19.
- Davis L, Cook-Sather SD, Schreiner MS. Lighted stylet tracheal intubation: a review. Anesth Analg. 2000;90(3):745-756.
- Frass M, Kofler J, Thalhammer F, et al. Clinical evaluation of a new visualized endotracheal tube (VETT). Anesthesiology. 1997;87(5):1262-1263.
- Tuckey JP, Cook TM, Render CA. Forum. An evaluation of the levering laryngoscope. Anaesthesia. 1996;51(1):71-73.
- Cooper RM. Use of a new videolaryngoscope (GlideScope) in the management of a difficult airway. Can J Anesth. 2003;50(6):611-613.
- Agro F, Barzoi G, Montecchia F. Tracheal intubation using a Macintosh laryngoscope or a GlideScope in 15 patients with cervical spine immobilization (letter). Br J Anaesth. 2003;90(5):705-706.
- Gorback MS. Management of the challenging airway with the Bullard laryngoscope. J Clin Anesth. 1991;3(6):473-477.
- Bjoraker DG. The Bullard intubating laryngoscopes. Anesthesiol Rev. 1990;17(5):64-70.
- Wu TL, Chou HC. A new laryngoscope: the combination intubating device. Anesthesiology. 1994;81(4):1085-1087.
- Verghese C. Airway management. Curr Opin Anaesthesiol. 1999;12(6):667-674.
- Benumof JL. Laryngeal mask airway and the ASA difficult airway algorithm. Anesthesiology. 1996;84(3):686-699.
- Patel P, Verghese C. Delayed extubation facilitated with the use of a laryngeal mask airway in the intensive care unit. Anaesthesia. 2000;55(4):396.
- Brimacombe J, Keller C, Hörmann C. Pressure support ventilation versus continuous positive airway pressure with the laryngeal mask airway: a randomised, crossover study of anesthetized adult patients. Anesthesiology. 2000;92(6):1621-1623.
- Dörges V, Ocker H, Wenzel V, et al. The laryngeal tube: a new simple airway device. Anesth Analg. 2000;90(5):1220-1222.
- Gaitini LA, Vaida SJ, Somri M, et al.. A comparison of the Cobra, Perilaryngeal Airway, and Laryngeal Mask Airway Unique in spontaneously breathing adult patients. Anesthesiology. 2004;101:A518.
- Gupta B, McDonald JS, Brooks JH, et al. Oral fiberoptic intubation over a retrograde guidewire. Anesth Analg. 1989;68(4):517-519.
- Sivarajan M, Stoler E, Kil HK, et al. Jet ventilation using fiberoptic bronchoscopes. Anesth Analg. 1995;80(2):384-387.
- Audenaert SM, Montgomery CL, Stone B, et al. Retrograde-assisted fiberoptic tracheal intubation in children with difficult airways. Anesth Analg. 1991;73(5):660-664.
- Klain M, Smith RB. High-frequency percutaneous transtracheal jet ventilation. Crit Care Med. 1977;5(6):280-287.
- Enk D, Busse H, Meissner A, et al. A new device for oxygenation and drug administration by transtracheal jet ventilation. Anesth Analg. 1998;86(25):S203.
- Safar P, Penninckx J. Cricothyroid membrane puncture with special cannula. Anesthesiology. 1967;28(5):943-948.
- Safar P, Bircher NG. Cardiopulmonary Cerebral Resuscitation (3rd ed.). London, England: WB Saunders; 1988.
- Wong EK, Bradrick JP. Surgical approaches to airway management for anesthesia practitioners. In: Hagberg CA, ed. Handbook of Difficult Airway Management. Philadelphia, PA: Churchill Livingstone; 2000:209-210.
- Gibbs M, Walls R. Surgical airway. In: Hagberg CA, ed. Benumof’s Airway Management 2nd ed. Philadelphia, PA: Mosby Elsevier; 2007:678-696.
- Sarpellon M, Marson F, Nani R, et al. Translaryngeal tracheostomy (TLT): a variant technique for use in hypoxemic conditions and in the difficult airway [in Italian]. Minerva Anesth. 1998;64(9):393-397.
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3-D video simulates severe bleeding for combat medics’ training
Fluid dynamics principles used to calculate and model highly realistic anatomy and bleeding from a shrapnel wound
Yesterday at 6:00 PM (source: http://www.ems1.com/ems-products/Bleeding-Control/articles/33158048-3-D-video-simulates-severe-bleeding-for-combat-medics-training/?nlid=&utm_source=iContact&utm_medium=email&utm_content=TopNewsRelated1Title&utm_campaign=EMS1Member)
BOSTON — A 3-D simulation of hemorrhage, caused by shrapnel in a human lower leg, was created as a training aide for combat medics.
The video, presented at the fluid dynamics meeting of the American Physical Society by UCLA investigators, adapts smoothed particle hydrodynamics and a 3-D reconstruction of the skin, bone and internal tissue of a lower leg.
The team simulated a lower leg shrapnel wound because of the frequency of those injuries on the battlefield and because the geometry of the leg is relatively easy to model, reported the New Scientist.
“We’re genuinely hopeful that our simulations will enhance the educational experience for medical trainees,” said Jeff Eldredge, who led the work. “We are solving the governing equations of fluid dynamics and tissue mechanics, so these are truly physics-based simulations.”
In the future the research team hopes to add treatments, like tourniquets and drugs, to allow medics to see the real-time impacts on hemorrhage control.
Heater–cooler devices are used during cardiothoracic surgeries, as well as other medical and surgical procedures to warm or cool a patient to optimize medical care and improve patient outcomes. These devices include water tanks that provide temperature-controlled water to external heat exchangers or warming/cooling blankets through closed circuits. Although the water in the circuits does not come into direct contact with the patient, there is the potential for contaminated water to enter other parts of the device or be aerosolized through the device’s exhaust vent into the environment and to the patient, according to the FDA.
- Strictly adhere to the cleaning and disinfecting instructions provided in the manufacturer’s device labeling. Ensure you have the most current version of the manufacturer’s instructions for use readily available to promote adherence.
- Do not use tap water to rinse, fill, refill or top off water tanks, as this may introduce NTM organisms. Use only sterile water or water that has been passed through a filter of less than or equal to 0.22 μm.
- When making ice needed for patient cooling during surgical procedures, use only sterile water or water that has been passed through a filter of less than or equal to 0.22 μm. Deionized water and sterile water created through reverse osmosis are not recommended because it may corrode metal components of the system.
- Direct the heater–cooler’s vent exhaust away from the surgical field to mitigate the risk of aerosolizing heater–cooler tank water into the sterile field and exposing the patient.
- Establish regular cleaning, disinfection and maintenance schedules for heater–cooler devices.
- Develop and follow a comprehensive quality control program for maintenance, cleaning and disinfection of heater–cooler devices.
- Immediately remove from service heater–cooler devices that show discoloration or cloudiness in the fluid lines/circuits, which may indicate bacterial growth. Consult the hospital infection control officials to perform the appropriate follow-up measures, and report events of device contamination to the manufacturer.
- Consider performing environmental, air, and water sampling and monitoring if heater–cooler contamination is suspected.
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All-in-one superabsorbent stretcher pad cover and patient transfer device
The superabsorbent, tear-proof stretcher pad cover and patient transfer device has numerous advantages in any situation requiring patient
First: up to 2.5 Liters (2.64 US quarts) of potentially infectious fl uid, is reliably absorbed and stored in the collection core. Stretcher, beds, and
treatment tables stay clean and dry. Cleaning the stretcher after using Trumla is typically much quicker and easier.
Secondly, because of the reinforced edges on the pad cover, patients weighing up to 210 kg (462 lbs) can be easily and securely transferred.
The Trumla® pad cover can also remain with the patient during transfer from the emergency vehicle to the hospital, where it can then be safely
disposed of. A clean and secure solution that benefi ts both patients and medical professionals.
● Demonstrated to absorb up to 2,5 liters (2.64 US quarts)
● Proven to trap germs
● Rip-proof up to 210 kg body weight (approx. 463 pounds)
● Reliable patient transfer device, size 220 x 100 cm
● Easy disposal
● Enormous potential to save time and costs when cleaning the vehicle and stretcher
● Shorter downtime for EMVs, quicker turnaround to be operational again
The process of cleaning and preparing an ambulance, including the stretchers, for use again after an emergency call requires a great deal of time and effort. Depending on the amount and consistency of the fl uid that has been exuded during patient transport, cleaning the vehicle and stretchers can take up to and sometimes longer than half an hour. The total costs for cleaning and disinfecting materials, personnel, and missed revenue due to being grounded can quickly add up. Using the superabsorbent stretcher pad Trumla® can significantly decrease these expenses.