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Trauma has assumed epidemic proportion. 10% of global road accident deaths occur in India. Hypoxia and airway mismanagement are known to contribute up to 34% of pre-hospital deaths in these patients. A high degree of suspicion for actual or impending airway obstruction should be assumed in all trauma patients. Objective signs of airway compromise include agitation, obtundation, cyanosis, abnormal breath sound and deviated trachea. If time permits, one should carry out a brief airway assessment prior to undertaking definitive airway management in these patients. Simple techniques for establishing and maintaining airway patency include jaw thrust maneuver and/or use of oro- and nas-opharyngeal airways. All attempts must be made to perform definitive airway management whenever airway is compromised that is not amenable to simple strategies. The selection of airway device and route- oral or -nasal, for tracheal intubation should be based on nature of patient injury, experience and skill level.
The global status report on road safety published in May, 2011 by world health organization noted that India had the maximum (125,000) deaths due to trauma on roads. This is 10% of global road accident death. The report also adds that “at least 2.2 millions sustain serious injuries each year”. Unfortunately, a majority of trauma survivors are either confined to bed or wheel chair for the rest of their lives due to either brain or spinal injury.
The tragedy of India is that 78% of the victims are men in the age group of 20 to 44 years, causing significant impact on productivity.
Why do these trauma victims die? This is predominantly due to hypoxia and airway mismanagement which are known to contribute up to 34% of pre-hospital deaths in these patients.
The best strategy to salvage patients with trauma is to provide them with immediate trauma care, including airway management in the pre-hospital setting and advance trauma care within the first hour of trauma or the so-called Golden Hour.
The aim of this article is to review the more recent theoretic and practical information that pertains to airway management in victims of trauma. This shall include identifying causes of difficulties in airway management, prediction of airway difficulties and the best strategies in terms of airway devices, techniques or maneuvers that may be useful in the management of airway in the trauma setting.
Airway mismanagement in trauma victims may be attributed to any one or combination of the following causes:
An inadequate airway would lead to asphyxia that may progress to cerebral hypoxia, brain damage and finally death.
What are the locations at which airway mismanagement occurs in these trauma patients? The answer to this includes airway mismanagement can occur at the accident site or the trauma centre. Causes of airway mismanagement at the accident site include the following:
Causes of airway difficulties leading to airway mismanagement at the trauma centre may include the following:
All or some of these factors, as well as poor airway skills of the operator themselves, result in a difficulty in managing the airway in 7 to 10% of trauma patients. To avoid airway mismanagement, it is essential that the physician or paramedic attending to the patient is well trained, remains calm and does not panic. One should strictly follow the A, B, C……. rules of Advanced Trauma Life Support guidelines.
Potential trauma patients who can have inadequacy of airway include patients with:
Not all these patients will have a compromised airway. The following steps shall help to identify the obstructed airway of some of these potential patients:
Patients with any or combination of the above should be presumed to have an inadequate obstructed airway needing appropriate management. All patients of trauma should be suspected to have an altered or compromised airway till ruled out. They should continue to receive supplemental oxygen and have cervical immobilisation done using manual-in-line stabilisation during examination and airway management.
While trying to identify an inadequate airway, take the opportunity to take a SAMPLE history if patient's condition permits. This includes the following:
The 8th edition advanced trauma life support (ATLS) guidelines strongly suggest that if the patient is well oxygenated and is reasonably stable (i.e., does not need to be intubated in the next 2 to 3 minutes), a methodical stepwise plan to assess for difficult airway should be made. For ease of remembrance, one is encouraged to use the following mnemonic for assessing the difficult airway in these patients: LEMON and BONES.
Difficult mask ventilation may be anticipated if the patient has 2 or > of the following parameters in the mnemonic.
Once it has been identified that the patient has an inadequate airway, one can adopt:
However, before initiating any of the airway maintenance strategies, it is essential to clear any blood clot and mucous from the oral cavity and nose. Remove foreign bodies such as broken dentures or avulsed teeth. One should also control the tongue position in case of symphyseal bilateral fracture of the mandible. Words of caution when suctioning the oral cavity: never suction further than you can see, always suction on the way out, never suction for longer than 15 seconds and always oxygenate the patient before and after suctioning.
This includes Head tilt and Chin lift (avoid in patients with cervical trauma)/jaw thrust or the use of basic adjuncts such as oropharyngeal airway in unresponsive patients without gag reflex, and/or nasopharyngeal airway in patients with more active reflexes but without evidence of fracture of base of skull.
This includes either ETI or a surgical airway. Indications for definitive airway strategy include the following:
Options for achieving ETI may include any one of the following airway aids depending on the situation, device availability and presence of operator with necessary expertise.
Direct rigid laryngoscopy using a straight or a curved blade laryngoscope is still the most successful aid in performing ETI in patients with trauma. This is because we have vast experience with its daily use; vision is not hampered in the presence of blood/secretion/vomitus, and it is robust enough while dealing with an uncooperative/combative patient. It has been erroneously believed that direct conventional laryngoscopy is associated with significant movement of the cervical spine. Cadaveric and studies done on live trauma patients have failed to support this assumption. Today, there is enough evidence that a gentle direct laryngoscopy with MILS is not associated with any aggravation of spinal cord injury.[12,13]
Video laryngoscopes such as GlideScope™ (Verathon, Bothell, Washington), TruviewPCD™ (Truphatek, Israel), McGrath™Aircraft Medical Ltd., Edinburgh, UK) and others give the ability to view the images on a monitor, thereby providing immediate feedback to an assistant applying external laryngeal manipulation. In addition, videolaryngoscopic techniques also have a great potential for teaching the art of airway management in trauma patients. But these techniques have their share of disadvantages such as blurring of view in presence of blood and secretions besides being expensive.
Fibre optic tracheal intubation is considered to be the preferred method for intubating a patient with an unstable cervical spine. Least cervical spine movement is associated with fibreoptic tracheal intubation. In the emergency department, the success rate of this airway aid ranges between 50 and 90%.[16–18] However, one should remember that it is most likely to fail in the presence of blood, secretion and vomitus or in an uncooperative, combative patient.
Lightwand (Trachlight™: Laerdal Medical Corp., Wappingers Falls, New York) is a safe, effective, rapid and inexpensive intubating device. Lightwand tracheal intubation is a suitable airway aid in trauma patients where intubation is to be done in the neutral position or with minimal head extension. Its second major advantage is that its success is not significantly impacted by the presence of blood and secretion. However, since this method of intubation is a blind approach, it should be avoided in patients with expanding neck masses or laryngopharyngeal trauma.
Intubating LMA/C-Trach™-aided tracheal intubation has been used in trauma patients for achieving tracheal intubation. They require minimal head and neck movement while placing them into the patient's oropharynx and facilitate ETI as the patient is being simultaneously ventilated. However, Brimacombe et al. have demonstrated that its use may be associated with significant displacement of the unstable cervical vertebra. Intubating laryngeal mask airway (LMA) has been noted to cause greater cervical vertebra displacement as compared with conventional orotracheal intubation. Hence, one should be cautious in its use in patients with cervical injury.
Bullardlaryngoscope™ (Circon Corp., Stamford, Connecticut), UpsherScope™ (Mercury Medical, Clearwater, Florida) or WuScope™ (Achi Corp., San Jose, California)-aided tracheal intubation have the advantage of conventional fibreoptic scope. In addition, they are more robust and need less intensive training. Because of their anatomically curved shape, they are especially suited for patients with cervical spine injury as no head and neck movement is necessary for their use. Cricoid pressure and inline stabilisation of the head and neck does not seem to interfere with the utility of Bullard™ scope. Like any other fibreoptic laryngoscopes, these are handicapped by their inability to aid visualisation of the larynx in the presence of blood, vomitus or secretions. However, WuScope™ is partly protected from this handicap as its optical system is relatively protected in its tubular blade.
Blind nasotracheal intubation, though still a part of ATLS, has very few indications in trauma patients. One such indication may be limited mouth opening as all other devices detailed above require a mouth opening of at least 2 cm for orotracheal intubation. In such situation, nasotracheal intubation may be attempted if surgical airway is not immediately indicated. One should remember that it should be undertaken only by expert personnel. Contraindications to nasotracheal intubation are significant midface trauma and coagulopathy.
Once tracheal intubation has been achieved, it is essential to confirm correct tracheal tube placement. This is done by either visualising the tracheal tube pass through the vocal cords or using other methods such as watching the chest move and auscultating 5 points on the patient's chest; CO2 detector and a chest X-ray. Capnography (continuous CO2 detection with a waveform) is the recommended method now. Only when it is not available, capnometry (single measurement of CO2) should be resorted. Once correctly placed, do not forget to secure the endotracheal tube lest it gets displaced.
Gum elastic bougie is an underutilised airway aid in the setting of trauma airway management. Its advantage lies not only in making a difficult intubation possible when only a portion of laryngeal inlet or epiglottis alone is visualised, but its use is also not affected by the presence of blood and secretion.[10,22,23] All trauma care operators should be satisfied with a Cormack and Lehane's class 2 or 3 view and use a bougie to aid tracheal intubation rather than use force to obtain class 1 view and aggravate cervical injury.
Surgical airway should be resorted when there is severe glottis oedema and/or oropharyngeal haemorrhage, fracture of the larynx and when endotracheal tube fails to be passed through the vocal cords. 1% of trauma patients requiring intubation require a surgical airway. Surgical airway techniques include cricothyrotomy. Cricothyrotomy can be performed using the following three techniques:
Percutaneous tracheostomy (PCT) is not recommended in the trauma setting. This is essentially because for performing PCT, one needs to hyperextend the patient's neck. This can have disastrous consequences if the patient has a cervical injury. This procedure can be dangerous and is time-consuming and hence not advocated.
The role of semi-definitive devices (supraglottic airway devices) has been clearly defined in the management of trauma patients in the 8th edition of ATLS. A simplified approach to definitive airway management in trauma patients in presented in Figure 1. The three devices which are recommended include LMA, Combitube and laryngeal tube (LT).
The LMA is considered a useful airway device in any patient where definitive airway could not be established. However, LMA is not considered a definitive airway device. ATLS strongly recommends that physicians should plan for a definitive airway when patient with this device arrives in the emergency department. It has been recognised that for proper placement of LMA, appropriate training is essential.
The LT is supraglottic airway device with capabilities similar to LMA. As with the LMA, LT is not considered a definitive airway device. Like the LMA, LT is placed without direct visualisation of the glottis and does not require significant manipulation of the head and neck. Unlike the combitube and ETI, LT offers improved insertion success and lesser placement time.
It is still recommended as a semi-definitive airway device to be used in trauma patients where facilities for definitive airway do not exist or have failed. It is a time purchase device and all attempts should be made to switch over to a definitive airway device at the earliest. Unlike the LT, it may rarely enter into the trachea. In such circumstances, an immediate switch over to the other proximal lumen should be done for initiating correct ventilation.
Miscellaneous issues during the airway management of trauma patient. These issues include the following: role of cricoid pressure and cervical immobilisation, dealing with a combative patient and dilemma of awake tracheal intubation.
Cricoid pressure, the “Sellick's maneuver,” is not mentioned in the 8th edition of ATLS course manual except as a single line under rapid sequence intubation. Although it has been used to prevent regurgitation of gastric contents, it is known to distort the laryngeal view and displace unstable cervical spine. If still utilised, cricoid pressure should be reduced or altogether removed, if felt that it is hampering tracheal intubation or placement of supraglottic device.
In a non-randomised comparative evaluation of three techniques of cervical spine immobilisation (rigid cervical collar, tape across forehead with sandbags on either side of the neck and manual-in-line-stabilisation) on laryngoscopic view of the glottis during laryngoscopy, Heath noted poor laryngoscopic view (grade 3 or 4 of Cormack and Lehane's) in 64% patients when cervical immobilisation was attempted using rigid collar or tape across forehead as compared with only 22% when using MILS. Hence, MILS should be the favoured technique of cervical spine immobilisation in patient with suspected neck trauma.
Patients with trauma may be combative as a result of intoxication (alcohol or drugs), but other equally important factors are because they are hypoxic, hypercarbic, head injured, frightened, disoriented or are in severe pain. One should also remember that there may be underlying medical condition such as hypoglycaemia contributing to their combative behaviour. Addressing all these contributing factors should go side by side to airway management. Physical and chemical restraint during airway management should be restricted to patients in whom the above factors have been either ruled out or have been adequately attended. Physical restraint may be achieved by placing the patient on a long spine board with a cervical collar, tape and sandbags. However, if the patient continues to struggle, he can potentially injure his spine and warrants further action. In the haemodynamically stable patient, haloperidol, 5 mg, can be given in repeated doses intravenously every 5 minutes with observation for effect.
A commonly held belief in the 1970s and 1980s was that definitive airway management in an awake patient protects the injured cervical spine as the non-paralysed neck muscle tone acts as a splint. There is no evidence to support this assumption. In fact, such patients can significantly aggravate their cervical injury due to coughing, bucking, gagging or struggling. In the National Emergency Airway Registry, a multicentre study of more than 15,000 emergency intubations, a phase-two data analysis of trauma intubations showed that 80% of patients underwent rapid sequence induction and intubation using muscle relaxant without cervical damage.
Rapid sequence induction and tracheal intubation under anaesthetic, sedative and neuromuscular blocking drug is still considered hazardous. However, if the situation justifies the risk of administering these drugs, one should assure that skilled personnel are available to perform tracheal intubation.
Following steps should be strictly adhered to while carrying out rapid sequence intubation:
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Conflict of Interest: None declared.