Thursday, March 5, 2009


The first concern in the management of a patient in critical condition is adequacy of the airway. Partial or complete airway obstruction must be overcome quickly. In some cases, such as an airway obstructed by a tongue, simple maneuvers will suffice. In other cases, particularly those in which myriads of obstructing agents are combining to block the airway, the task will be formidable. The tongue, dentures, swollen or distorted tissues, blood, and vomitus are common obstructing agents that make intubation difficult. Clearing obstructing agents may be made more difficult by muscular activity due to reflex stimulation or patient efforts to improve oxygenation. Moreover, the neck motion required for suction and intubation must be carefully managed in the face of potential cervical spine instability.
The wide availability of pulse oximetry monitors has greatly improved our ability to monitor oxygenation for patients at risk of airway or ventilatory compromise. Clinically subtle deterioration is much more quickly and easily recognized using the monitors. They have become standard equipment in emergency departments, intensive care units, and operating rooms to allow early recognition of patient deterioration.

Airway Maneuvers
Partial or complete airway obstruction resulting from lax musculature and tongue occlusion of the posterior pharynx may be overcome by a variety of maneuvers. The relative benefits of various airway-opening maneuvers have been examined. In a study of 120 anesthetized patients whose airways were obstructed by their tongues, Guildner compared the ease of performance of the neck-lift and head-tilt method, the jaw-thrust method, and the chin-lift method. He concluded that the chin lift was the easiest to perform and produced the greatest airway patency of the three methods tested. Besides offering greater patency, the chin-lift method has the additional advantage that neck extension is unnecessary.
Partial airway obstruction in the patient with a decreased level of consciousness is commonly due to posterior displacement of the tongue. This may be recognized readily in the presence of snoring or stridor, but an apneic patient or one who is moving minimal air may not exhibit any audible evidence of airway obstruction. Some type of jaw-thrust or chin-lift maneuver should be performed on every unconscious patient to ensure airway patency. When uncertain about cervical spine status, the neck must be maintained in the neutral position. If the patient was found with a flexed or extended neck, the neck should first be restored to neutral position with gentle longitudinal traction. The chin-lift or jaw-thrust method is then performed. A combination of these maneuvers usually clears airways obstructed as a result of the position of the neck itself. The neck-lift and head-tilt maneuver, as described in cardiac life support courses, should not be used when cervical spine injury is suspected, because the extension of the spine produced during the maneuver endangers the spinal cord.
Clearing the airway of foreign material requires more than a simple jaw thrust. The occasional patient who presents with complete airway obstruction secondary to food aspiration may be treated with abdominal thrusts as described in basic cardiac life support.
Partial or complete airway obstruction can be the result of upper airway hemorrhage, accumulation of the patient's own secretions, vomitus, or fractured dentition. When deciding on airway-clearing maneuvers, one must take these circumstances into account. Neck extension must be avoided or carefully minimized if the probability of a cervical spine injury is high. When stability of the spine is a concern, application of the abdominal thrust should be limited to the supine method described for unconscious victims. The abdominal thrust carries significant risks, compelling the rescuer to weigh the benefits of its application.

The Chin-Lift Maneuver
The rescuer places the tips of the fingers, volar surface superiorly, beneath the patient's chin. The jaw is lifted gently forward. The patient's mouth is opened by drawing down on the lower lip with the thumb of the same hand. Mouth-to-mouth resuscitation or other means of positive-pressure ventilation is provided if the patient is not ventilating spontaneously.

The Jaw-Thrust Maneuver
The jaw-thrust maneuver is the second choice, again because neck extension is not necessary. Forward traction on the mandible is achieved by using two hands to grasp the mandibular rami and pull them forward.

The Abdominal Thrust
The abdominal thrust is a method to relieve a completely obstructed airway. The technique was popularized by Dr. Henry Heimlich and is commonly referred to as the Heimlich maneuver. The technique is most effective when a solid food bolus obstructs the larynx. Although a subject of controversy, a role for the maneuver has not been found for the resuscitation of near-drowning victims.
The conscious patient with an obstructed airway exhibits increased respiratory effort, anxiety, aphonia, and, occasionally, cyanosis. In the conscious patient, the maneuver is performed with the rescuer positioned behind the upright patient. The rescuer's arms are circled about the patient's midsection with the radial side of the clenched fist placed in the epigastrium of the patient. Care is exercised to position the fist midway between the umbilicus and the xiphoid of the patient. After proper positioning, the rescuer grasps the fist with the opposite hand and delivers an inward and upward thrust to the abdomen. A successful maneuver will cause the obstructing agent to be expelled from the patient's airway by the force of air exiting the lungs.
An unconscious, supine patient must be handled differently: the rescuer kneels next to the patient's pelvis facing cephalad. The palmar bases of the hands are placed in an overlapping fashion on the epigastrium at the same spot as that used in the upright patient. Inward, upward thrusts are delivered in this fashion with the same objective.
Abdominal thrusts are relatively contraindicated in pregnant patients and others with protuberant abdomens. A chest thrust similarly to that delivered in closed chest massage may be used instead. The upright patient may be delivered a chest thrust by placing the fist over the sternum. Experimental primate models of infant airway obstruction show higher peak airway pressures with chest thrusts than with abdominal thrusts; a combined (simultaneous) chest and abdominal thrust produce even higher peak airway pressures. [6] Hence, a combined maneuver should be considered in the case of total airway obstruction that is unresponsive to simple abdominal thrusts.
Visceral injury can occur with the Heimlich maneuver. Excessive force may be responsible in such cases. In others, incorrect placement of the hands may play a role. Nonetheless, the technique can be life saving and should be used when needed. Attention to proper execution may limit complications.

Positioning the patient who has sustained multiple trauma can be a problem. Spinal injury and airway access priorities dictate that the patient should be kept in the supine position while immobilized on a backboard. Turning the patient on the side allows upper airway hemorrhage, secretions, and vomitus to drain externally rather than to collect in the patient's mouth, which can lead to aspiration and airway obstruction.
Guidelines for patient positioning must take into account the status of the patient's spine and the use of gravity to enable secretions to drain rather than accumulate in the airway. The following is a judicious approach to airway management in a patient with spontaneous respiration:

  1. Initial airway maintenance accomplished by the chin-lift maneuver and the application of cervical stabilization
  2. Immobilization of the patient on a spinal backboard.
  3. With the position of the neck controlled, transportation of the patient on the side to facilitate airway drainage.

Patient positioning and airway opening and clearing maneuvers are often inadequate to achieve the degree of airway patency desired. Ongoing hemorrhage, vomitus, and particulate debris often require suction to clear and maintain the respiratory passage. Three basic types of suctioning tips are available . Each is suited to different types of airway obstruction problems.
Dental tip suction is most useful for clearing particulate debris from the upper airway. Vomitus is most readily cleared with this tip because it is least likely to become obstructed itself by particulate matter. The tonsil tip (Yankauer) suction device is used most effectively to clear upper airway hemorrhage and secretions. Its design is intended to prevent the obstruction of its tip by tissue and clot. The rounded tip is also less traumatic to soft tissues.
Unfortunately, the catheter tip suction device is the one most readily available in many hospitals. Often it is the only type of suction available. This device is inferior to the other catheter tips for suctioning before the patient has been intubated. After intubation, it works well for suctioning the trachea and bronchi through the tracheal tube. The dental tip device should be used during the resuscitation period and should be ready at the bedside. The dental tip allows rapid clearing of both particulate matter and hemorrhage, thereby expediting airway control.
Optimally, stabilization of the patient with multiple injuries will involve use of all three types of suction tips. The tonsil or dental tip should be attached to the suction source during the interval between patient evaluations because it is most likely to be the one needed on short notice. Both the tonsil tip and catheter tip should be stored next to the suction source so they can be attached when needed. It is essential that all physicians and nurses know the location of suction equipment and know how to turn it on during an emergency. In the resuscitation rooms, the equipment should be connected and ready to operate and not kept in cabinets or wrapped in difficult-to-open packaging material . Interposition of a suction trap at the base of the dental tip suction device prevents clogging of the tubing with particulate debris. A trap that fits directly onto a tracheal tube has been described; use of this device allows effective suctioning during intubation.
Although no specific contraindications to airway suctioning exist, complications of incorrectly performed suctioning may be significant. Nasal suction is seldom required to improve oxygenation (except in infants), because most adult airway obstruction occurs in the mouth and oropharynx. Vigorous nasal suction can induce epistaxis and further complicate an already difficult situation. Suctioning that is prolonged may not be recognized during an emergency, but it should be avoided because it may lead to significant hypoxia, especially in children. Suctioning should not exceed 15-second intervals, and the provision of supplemental oxygen before and after suctioning should be routine . Basilar skull fractures can allow the inadvertent placement of nasal suction tubes in the brain. Extreme care should be exercised when a basilar skull or facial fracture is suspected, because communication between nasal and intracranial cavities may exist.
Generally, it is best to perform suctioning under direct visual inspection or with the aid of the laryngoscope. Forcing a suction tip blindly into the posterior pharynx can injure tissue or convert a partial obstruction to a complete obstruction.
Complications may be avoided by anticipating problems and providing appropriate care during suctioning maneuvers. Epistaxis may be avoided by limiting the force applied during suctioning. Vasoconstrictor drops or spray, such as 0.25% phenylephrine, constrict the nasal mucosa and reduce the injury potential in patients who require repeated nasopharyngeal suctioning. The rescuer must be aware that the patient may develop transient pupillary dilation if the vasoconstrictor solution drips into the conjunctival space. Naigow and Powasner found that suctioning induced hypoxia in dogs consistently and that it was best avoided by hyperventilating the animals before and after suctioning.

Artificial Airways
Indications and Contraindications
Once the airway has been established through various maneuvers and suctioning, the patient may require further temporary support to maintain airway patency. The semiconscious patient who is breathing with an adequate rate and tidal volume at the time of the chin-lift maneuver may develop hypoxia because of recurrent obstruction if the maneuver is discontinued. Oxygen supplementation and an artificial airway may be all the support that is necessary. The use of an artificial airway also allows more efficient use of rescuer skills and relief from fatigue that is caused by the continuous application of chin-lift or jaw-thrust maneuvers.
Positive-pressure ventilation with a bag-valve-mask (BVM) device may be necessary to bolster the patient's inadequate ventilatory effort or to provide total ventilation in cases of apnea. By maintaining airway patency, artificial airways facilitate spontaneous and bag-mask ventilation.

Airway Placement Technique
The simplest artificial airways are the oropharyngeal and nasopharyngeal airways . Both are intended to prevent the tongue from obstructing the airway by falling back against the posterior pharyngeal wall. The oral airway may also prevent teeth clenching. The oropharyngeal airway may be inserted by either of two procedures. In the first procedure, the airway is inserted in an inverted position along the patient's hard palate. When it is well into the patient's mouth, the airway is rotated 180° and advanced to its final position along the patient's tongue, with the distal end of the airway lying in the hypopharynx. The second procedure involves the performance of a jaw-thrust maneuver, either manually or with a tongue blade, and the simple advancement of the airway into the mouth to its final position. No rotation is performed when the airway is placed in this manner. Once inserted, the oral airway may have to be taped in place to prevent expulsion by the patient's tongue.
The nasopharyngeal airway is placed by gently advancing the airway into a nostril, directing the tip along the floor of the nose toward the nasopharynx. When in final position, the flared external end of the airway should rest at the nasal orifice. Either of these two airways provides airway patency similar to that in a correctly performed chin-lift maneuver, but the nasal airway may be better tolerated by the semiconscious patient.

Few complications are encountered in the use of these airways. The oropharyngeal airway may cause obstruction if during its placement the tongue is pushed against the posterior pharyngeal wall. Care in placement will prevent this occurrence. In the patient whose reflexes are intact, the gag reflex may stimulate retching and emesis, and the semiconscious patient may not tolerate the oropharyngeal airway. If gagging is a persistent problem, the airway should be removed and a nasal airway or tracheal intubation should be considered. If the patient with airway compromise is comatose and lacks a gag reflex, the oropharyngeal airway should not be used as a definitive airway; tracheal intubation should be used instead. The oropharyngeal airway will keep the mouth partially open if an orogastric tube is placed for gastric lavage or suction, and it will prevent clenching of the teeth, which can obstruct an orotracheal tube.
The nasopharyngeal airway may offer an advantage over the oropharyngeal airway in that the nasopharyngeal airway is less likely to induce gagging. The same considerations that apply to nasal suctioning apply to placement of the nasopharyngeal airway. That is, care must be exercised not to induce epistaxis, and extreme caution is indicated in patients with a suspected basilar skull fracture or facial injury. All patients with oral or nasal pharyngeal airways should be observed constantly, because these devices are temporary measures and cannot substitute for tracheal intubation.