AIRWAY MANAGEMENT OVERVIEW

Under normal breathing, the lungs inflate under a slight vacuum when the chest wall muscles and diaphragm expand; causing air to enter and inflate the lungs under a gentle vacuum. Chest compressions performed during CPR result in passive-oxygen delivery as oxygen is forced out of the lungs during chest compression and drawn into the lungs during chest recoil.  Systemic and pulmonary perfusion is reduced during CPR resulting in minimal ventilation required to maintain adequate perfusion.  Thus, passive oxygen delivery resulting from chest compressions on a patient with a patent airway may be sufficient for the first several minutes of CPR.  Using various manual resuscitation methods during CPR results in positive-pressure ventilation.  During positive-pressure ventilation the lungs are force-inflated with pressurized air or oxygen. This inherently leads to risk of various complications, many of which depend on whether the manual resuscitator is being used with a face mask or ET tube. Complications are related to over-inflating or over-pressurizing the patient, resulting in gastric insufflation, volutrauma, and/or barotrauma.  Recently, it has been suggested that positive pressure ventilation may also interfere with circulation during CPR.  Overall, rescue breathing is less important than chest compression during the first several minutes of CPR because blood flow, rather than arterial oxygen content, is the limiting factor in oxygen delivery to the heart and brain during cardiac arrest.  Therefore, rescue breathing and oral tracheal intubation (OTI) should not delay or interrupt initial CPR and defibrillation during care of a patient in cardiac arrest.  Current recommendations suggest that if OTI will interrupt chest compressions for more than 10 seconds, ALS providers should consider using a supraglottic device (SGD) or defer placement until the patient fails to respond to initial CPR and defibrillation attempts. 1

Airway emergencies resulting from trauma to the larynx are uncommon.  Major medical centers report that only 8% of trauma involves the larynx; and of those, only 10% are attributable to athletics.  Laryngeal injuries resulting from athletics most often result from blunt trauma resulting from being hit by a ball or puck, from a direct blow, such as a punch or close lining, or from contact with other environmental hazards such as goal posts. 2 However, there is an apparent relationship between head and neck injury and laryngeal injuries that cannot be overlooked.  When evaluating athletes for potential head and neck injuries, sports medicine teams should have a high index of suspicion of corresponding laryngeal injury to ensure that a distracting head or neck injury does not result in overlooking injury to the larynx that may result in latent airway complications. 3  Therefore, sports medicine teams should include a systematic evaluation of the larynx in their head and neck injury assessment algorithm.3

Injury to the larynx has no clear presentation pattern.  However, the onset of hoarseness, dyspnea, difficulty swallowing, stridor, and subcutaneous emphysema is indicative of potential acute or latent airway complications.  The onset of airway complications secondary to trauma warrants immediate transport because traditional prehospital airway management techniques, including adjunct airways, may be ineffective or even contraindicated with severe injury to the larynx.  Traditional prehospital airway management techniques may be ineffective when there is trauma to the larynx because they do not bypass the larynx or may be contraindicated during instances where injury to the larynx has resulted in cartilaginous fracture or separation.2,3

Airway emergencies in athletics secondary to laryngeal injury are uncommon.  The more likely cause of an airway emergency in athletics is an upper airway obstruction.  Upper airway obstructions may be caused by a foreign object or may be tongue-based.  Foreign object upper airway obstructions in athletics are likely to be caused by an athlete’s mouth guard.  Tongue-based upper airway obstructions are common when an athlete is rendered unconscious allowing the tongue to fall back against the posterior pharyngeal wall.  Other medical conditions, such as anaphylaxis or laryngospasm, may also result in an upper airway obstruction.2,3

The onset of an upper airway obstruction or injury to the larynx will require the medical team to initiate airway management techniques to establish and maintain a patent airway.  The techniques used to establish, support, and maintain a patent airway will differ based on the qualifications of the medical staff present.  Athletic trainers are qualified to provide airway management using BLS airway adjuncts, including oropharyngeal and nasopharyngeal airways, bag ventilation mask, oxygen, and suction.  Airway management physicians and paramedics are qualified to use more advanced airway management techniques, including intubation using an endotrachial tube (ET), oesophageal tracheal combitube (OTC) laryngeal tube (LT), laryngeal tube with integrated suction tube (LTS), laryngeal mask airways (LMA), ProSeal laryngeal mask airways (PLMA), video laryngoscopes, and rapid sequence intubation (RSI).

Currently, the LMA, LT, and the OTC are the best evaluated and most commonly used advanced airway devices in the pre-hospital athletic environment.  The standard LMA and the PLMA have been shown to be effective during emergency airway management.  However, of concern with the LMA is the lack of reliable protection against aspiration.  The effectiveness of the inflatable LMA to provide reliable protection against aspiration has yet to be determined.  The OTC, though advocated for during prehospital emergency airway management, is limited by high airway morbidity and possible serious complications. 4,5

Stomach Inflation / Lung Aspiration

During positive-pressure ventilation, the intent is for the force-delivered air or oxygen to inflate the lungs.   However, air entering the patient also has access to the stomach via the esophagus.  If the resuscitator is squeezed too hard or too fast, the airflow may be too rapid for the lungs to absorb, resulting in the excess air being diverted to the stomach.   The resulting gastric inflation can lead to vomiting and subsequent aspiration of stomach contents into the lungs.  When stomach inflation leads to vomiting of highly acidic stomach acids, delivery of subsequent breaths can force these caustic acids down into the lungs where they cause life-threatening or fatal lung injuries.

Lung Injury and Air Embolism

When an endotracheal (ET) is placed, one of the key advantages is that a direct air-tight passageway is provided from the output of the manual resuscitator to the lungs, thus eliminating the possibilities of inadvertent stomach inflation or lung injuries from gastric acid aspiration. However, this places the lungs at increased risk from separate lung injury patterns caused by accidental forced over-inflation, called volutrauma and/or barotrauma. Sponge-like lung tissue is delicate, and over-stretching can lead to adult respiratory distress syndrome.  Lung volutrauma, may also result in pneumothorax