Airway and Ventilation Emergencies

pressure reduction with parenteral measures is not necessary but oral antihypertensives can be recommended.

If there are symptoms, some of these will be confusion, seizures, stroke-like symptoms, shortness of breath, chest pain, and sometimes evidence of acute azotemia, such as nausea and lethargy. Fundoscopy will be crucial to the evaluation as well as a mental status evaluation, urinalysis, lung and heart examination, and jugular venous distention. Papilledema will be an early finding. Those with neurological symptoms need a CT of the head. ECG will show acute ischemia or ventricular hypertrophy.

The goal is to reduce the mean arterial pressure by 20 to 25 percent in an hour or two using IV drugs like labetalol, nicardipine, nitroprusside, or fenoldopam. These drugs are helpful because they are titratable. It is not necessary to normalize the blood pressure acutely.

AIRWAY AND VENTILATION EMERGENCIES

In most medical situations, except for cardiac arrest, airway management takes priority in an emergency setting. There are three steps. The first is clearing the upper airway of mucus or other obstruction. The second is using a mechanical device, such as an oropharyngeal airway or nasal airway to maintain an open passage. The third is assisting the patient in ventilations.

Once ventilations are established, about six to eight milliliters per kilogram should be given per breath, along with a ventilatory rate of 8 to 10 breaths per minute. Even slower rates are recommended when air trapping is involved, such as COPD or asthma exacerbations. There are hemodynamic advantages to keeping the respiratory rate low.

The head tilt-chin lift and jaw-thrust maneuvers will help maximize airway patency. In cases of possible cervical fracture, the jaw lift maneuver, which involves drawing the mandible forward, will help to open the airway. Dentures, blood, and secretions can be removed manually or can be removed through suction. A Magill forceps can remove deeper material.

True airway obstruction might involve subdiaphragmatic abdominal thrusts, also called the Heimlich maneuver. Chest thrusts are instead done on very obese or pregnant patients until the airway clears or until unconsciousness occurs. This is done by standing behind the patient with fists clenched around the upper abdomen. Upward thrusts are given repeatedly in order to clear the blockage.

The unconscious patient with an obstructed airway is given CPR in order to increase the intrathoracic pressure. The oropharynx should be evaluated so that any foreign bodies can be removed with the fingers or with a Magill forceps. If the obstruction is below the vocal cords, the best way to remove the obstruction is to do CPR.

Infants should not have the Heimlich maneuver but should be held prone and be given five back thrusts followed by five chest thrusts, also in the prone and head-down position. This should be done repetitively until the obstruction is relieved.

Ventilation of the emergency patient can be done in several ways. Once an oropharyngeal airway or nasal airway is provided, a bag-valve-mask can be used, which ventilates the patient by providing firm pressure on the patient’s face so that air up to 100 percent inspired oxygen can be given. The biggest downside of this is that, if done for longer than five minutes, gastric distention can occur unless an NG tube is placed.

A laryngeal mask airway can be used to secure an airway for ventilation. These avoid the necessity of getting a good facial seal and can allow either an NG tube or endotracheal tube to be passed through it. Its biggest advantage is that it can be used if the endotracheal tube cannot be effectively passed. Vomiting and aspiration can happen if the gag reflex is intact. It is a good bridging device before a definitive airway can be established.

Endotracheal intubation can provide a definitive airway and will protect the airway. Pre-ventilation should involve several minutes of 100 percent oxygen. Other ways to ventilate the patient should always be available. A laryngoscope is used to visualize the cords so that the ET tube can be passed and later secured to the patient’s face. Suctioning prior to visualization may be necessary. Some patients will need vagolytic drugs, muscle relaxants, and sedatives if they are not completely unconscious. Use a