Combitube, Self-Inflating Bulb, and Colorimetric Carbon Dioxide Detector to Advance Airway Management in the First Echelon of the Battlefield, The

Military Medicine, May 2006 by Rich, James M, Thierbach, Andreas, Frass, Michael

Combat lifesavers and Army medics are regular combat soldiers who possess skills that enable them to provide lifesaving assistance to combat casualties. Although their training is not equal to that of paramedics, combat lifesavers and Army medics are trained to assess casualties for airway obstruction, as well as the presence or absence of spontaneous ventilation. They are also familiar with the same basic airway maneuvers that are required for blind insertion of the esophageal-tracheal double-lumen airway (ETDLA). Use of the ETDLA in combination with an esophageal detector device and a colorimetric carbon dioxide detector would require skill similar to that which they already possess in performing many mission-essential and combat lifesaver tasks. Because the U.S. Army has introduced the ETDLA for use, it is important that providers at all echelons understand the dynamics of the ETDLA. Inclusion of the ETDLA, esophageal detector device, and colorimetric carbon dioxide detector in combination with the bag-valve ventilation device could provide a viable alternative to mouth-to-mouth rescue breathing with the oral airway, as currently used by combat lifesavers on the battlefield. Improved airway management, in conjunction with other lifesaving measures, could potentially improve survival rates for combat casualties and assist in stabilizing them for evacuation to higher echelons of combat medical care.

Echelons of Combat Care

Since World War II, delivery of combat medical care has been separated into five echelons. Central to the U.S. Army echelon system is the interval process of stabilizing a patient with only the care necessary for either return to duty or evacuation to the next higher echelon. This is known as "phased wound management." Initiating care as soon as possible after wounding is known as "fix forward." Medical supplies, medical personnel, and medical care increase proportionately at each higher echelon of care.1 Echelon I is located forward of the battalion aid station to beyond the forward line of own troops. Triage is not available in echelon I, and care is provided exclusively by Army medics, combat lifesavers, self-aid, or buddy-aid. As long as signs of life are apparent, soldiers expend maximal effort to help buddies in the first echelon. '~3 The combat lifesaver role was developed to allow the concept of "fix forward" to begin in echelon I, beginning the process of phased wound management. Normally, each squad, team, crew, or equivalent-sized unit has one member trained to function as a combat lifesaver. Combat lifesavers are regular nonmedical soldiers who receive additional instruction in advanced first aid.12 Emergency care is rendered as soon as possible after injury occurs, and care ranges from simple to involved techniques.12 Intervention of these nonmedical soldiers is intended to help sustain the casualty until advanced measures can be applied at higher echelons of care. These soldiers bridge the gap between self-aid/buddyaid and the care given by combat medics.1

Airway Management Techniques Currently Used by Combat Lifesavers

Currently, only basic airway management techniques are used by combat lifesavers. These include the Heimlich maneuver, chin lift, jaw thrust, head tilt, and use of an oropharyngeal airway to facilitate mouth-to-mouth rescue breathing.2 This system provides only minimal airway control, marginal lung ventilation, and a high risk of gastric regurgitation and pulmonary aspiration.

Endotracheal intubation remains the standard method for airway control and protection. Tracheal intubation facilitates positive-pressure lung ventilation and provides the best protection of the airway and lungs from aspiration of gastric contents. However, training in endotracheal intubation requires time and resources that are beyond the scope of combat lifesaver training. Furthermore, tracheal intubation is a perishable skill that requires continued practice.4 In addition, the logistics and infection control challenges of maintaining a functional laryngoscope for extended periods in the field are impractical. Finally, the light emission from a laryngoscope could cause exposure to enemy fire.

Proposal for Improvement of Airway Management by Combat Lifesavers

Advanced airway devices that can be used by nonmedical attendants such as combat lifesavers currently exist. When applied in a systematic way, they can rapidly reverse airway obstruction, prevent respiratory arrest, and limit the risk of gastric aspiration, as well as the debilitating sequelae of hypoxemia, acidemia, and aspiration pneumonia.

The use of an esophageal-tracheal double-lumen airway (ETDLA) (Tyco Healthcare, Pleasanton, California) (Fig. 1) in combination with a self-inflating bulb5,6 and a colorimetric carbon dioxide detector7,8 and bag-valve device offers an improved standard of airway control, mirroring that of endotracheal intubation. The combined use of these portable "off-the-sheir airway adjuncts facilitates effective airway management and lung ventilation without the training needed to learn endotracheal intubation.8-10 The colorimetric carbon dioxide detector may be attached between the tube and the bag-valve immediately after intubation (Fig. 2). In the presence of a perfusing cardiac rhythm, the color of the membrane changes between purple and yellow in the presence of carbon dioxide, thus confirming trachea! ventilation. The disadvantage is that, in the presence of a nonperfusing cardiac rhythm, carbon dioxide may not be transported across the alveolar-capillary membrane in sufficient amounts to cause the membrane to change colors. In this situation, the self-inflating bulb (Fig. 3) should be used to determine which port of the ETDLA is providing tracheal ventilation.11 The self-inflating bulb can confirm tracheal ventilation within 4 seconds and has a low incidence of false-negative or false-positive results.6,12 It is collapsed, attached to the port of the ETDLA, and released (Fig. 4A). Rapid refill signifies communication with the trachea, and a continued collapsed state indicates communication with the esophagus (Fig. 4B). American Heart Association 2005 guidelines classify both the exhaled carbon dioxide detector and the esophageal detector device as Ua with regard to confirmation of endotracheal intubation.11 Class Ua designates a therapeutic option for which the weight of evidence is in favor of usefulness and efficacy.13 Because of insufficient evidence in the literature, neither has received a class Ua recommendation for use with advanced airways such as the ETDLA11; however, we have found both devices to work consistently well with the ETDLA.