Respiratory Distress D-2 Lecture Updated PDF

RESPIRATORY DISTRESS NICOLE EISENBERG, DDS, FACS ASSISTANT PROFESSOR AND DEPARTMENT HEAD ORAL & MAXILLOFACIAL SURGERY DIPLOMATE ABOMS GENERAL CONSIDERATIONS • To a conscious person, difficulty breathing is quite disconcerting. This section focuses on several common causes of respiratory distress...

RESPIRATORY DISTRESS NICOLE EISENBERG, DDS, FACS ASSISTANT PROFESSOR AND DEPARTMENT HEAD ORAL & MAXILLOFACIAL SURGERY DIPLOMATE ABOMS GENERAL CONSIDERATIONS • To a conscious person, difficulty breathing is quite disconcerting. This section focuses on several common causes of respiratory distress, including hyperventilation, asthma (bronchospasm), and foreign body obstruction. • Because persons in these types of respiratory distress usually remain conscious throughout the episode, this section also discusses the extremely important psychological aspects of patient management. AIRWAY OBSTRUCTION • In almost all medical emergencies involving the loss of consciousness, some degree of airway obstruction is present. • The primary cause of airway obstruction is mechanical—the tongue falling into the hypopharynx as skeletal muscle tone is lost. Two steps of basic life support—A (airway) and B (breathing)—are designed to manage this problem. • Awareness of all medical disorders the patient has helps the doctor to modify treatment to prevent or minimize exacerbation of that underlying condition. However, in some situations, such as asthma and heart failure, which represent chronic respiratory problems, the patient may experience difficulty breathing at all times. CLINICAL MANIFESTATIONS • Clinical manifestations of respiratory distress vary according to the degree of breathing difficulty present. In most cases the patient retains consciousness throughout the acute episode. • Although retention of consciousness is a positive sign, indicating that the patient is receiving at least the minimum amount of blood and O2 required for normal cerebral function, it does create an additional problem—acute anxiety. • The clinical symptoms of breathing difficulty and the sounds associated with it will vary according to the cause of the problem. • Asthmatic patients often exhibit characteristic wheezing sounds produced by turbulent airflow through narrowed bronchioles. Individuals suffering heart failure and pulmonary edema often cough and produce other sounds associated with pulmonary venous congestion. PATHOPHYSIOLOGY • The syndromes responsible for respiratory distress involve various segments of the respiratory system. • Bronchioles are the primary site of involvement in acute asthma (bronchospasm) • Hyperventilation is a more generalized problem. The site of origin of this disorder is the mind (brain) of the patient, and its clinical signs and symptoms are produced by an alteration in the chemical composition of the blood. • Acute foreign body (lower) airway obstruction (FBAO) is a potentially life-threatening situation in which a foreign body becomes impacted in the respiratory tract. • The level at which the airway becomes obstructed determines the severity of the situation and, to some degree, the manner in which it is managed. MANAGEMENT FOREIGN BODY AIRWAY OBSTRUCTION • During dental treatment there is great potential for small objects to drop into the posterior portion of the oral cavity and subsequently into the pharynx. • Because of its frequently sudden and critical nature, acute foreign body airway obstruction (FBAO) must be recognized and managed quickly. • The epidemiology of foreign bodies in the airway, pharynx, and esophagus peaks at the extremes of age. • Acute airway obstruction is the major cause of nontraumatic cardiac arrest in infants and children. • A third category of at-risk individuals are those undergoing procedures with sedation, particularly dental procedures or emergency intubation. FOREIGN BODY AIRWAY OBSTRUCTION • Despite best efforts at prevention, small objects, such as inlays, alloy, burs, or pieces of debris, may fall into the oropharynx of a patient and may subsequently be swallowed or aspirated. • When objects are swallowed, they usually enter the gastrointestinal (GI) tract. During the act of swallowing, the epiglottis seals the tracheal opening so that liquid and solid materials enter the esophagus, not the trachea. • More than 90% of swallowed foreign objects that successfully pass through the esophagus into the stomach and intestines pass completely through the GI tract without complications. • Objects aspirated into either the right or left main-stem bronchus can produce infection, lung abscess, pneumonia, and atelectasis. PREVENTION • The use of two major preventive measures— a rubber dam and oral packing. These measures significantly minimize the occurrence of swallowed or aspirated foreign objects. • Other preventive measures include patient positioning, the dental assistant, suction, Magill intubation forceps, and the use of ligature. RUBBER DAM Rubber dam effectively isolates the operative field from the oral cavity and airway, preventing foreign objects from being swallowed. The use of rubber dam is recommended in all possible situations. Unfortunately, use of the rubber dam during many dental procedures, such as periodontics and surgery, is not feasible. ORAL PACKING A pharyngeal curtain, created by the spreading of 4-inch by 4-inch gauze pads across the posterior portion of the oral cavity, effectively prevents small particles or liquids from entering into the airway LIGATURE The use of ligature (dental floss) can aid in the prevention of aspirated or swallowed objects and in their retrieval from the posterior regions of the oral cavity and pharynx. Dental floss should be secured to rubber dam clamps, endodontic instruments, cotton rolls, gauze pads; around pontics in fixed bridges; or to other small objects placed in the oral cavity during dental treatment The presence of dental floss lessens the possibility that a patient may swallow an object or inadvertently leave the dental office with a cotton roll remaining in the buccal fold. MANAGEMENT • Try to retrieve the object if it is visible in the oral cavity or have the patient remove it. • If the object cannot be seen (i.e., if the patient “swallows” it), radiographs are warranted to determine its location; the patient should not be permitted to leave the office without arrangements being made for these radiographs. (Patient will need CXR and KUB to see where the object went; lungs or abdomen) MANAGEMENT OF ASPIRATED FOREIGN BODY • Signs and symptoms include the sudden onset of coughing, choking, wheezing, and shortness of breath. More than 90% of patients who aspirate exhibit these signs and symptoms within 1 hour of aspiration. MANAGEMENT OF ASPIRATED FOREIGN BODY • If it is determined that the object is in the tracheobronchial tree, its most likely location is in the right bronchus. Compared with the left bronchus, the right main-stem bronchus takes a more direct path at the bifurcation of the trachea. • The right main bronchus branches off the trachea at a 25degree angle, whereas the left main bronchus branches off at a 45-degree angle. • Retrieval of the object from the bronchus may involve the use of a fiberoptic bronchoscope to locate (visualize) the object and bronchoscopy to retrieve it. • If bronchoscopy is unsuccessful (a rare occurrence), a surgical procedure known as thoracotomy may be necessary. RECOGNITION OF AIRWAY OBSTRUCTION • Acute upper-airway obstruction in the conscious person occurs most often while the patient is eating. • There are two categories of foreign body airway obstruction: complete and partial obstruction. • For management purposes, partial obstruction is subdivided into two categories: partial obstruction with good air exchange or partial obstruction with poor air exchange. COMPLETE AIRWAY OBSTRUCTION • Phase 1: (1-3 minutes). Patient is conscious, struggling, paradoxical respirations without air movement or voice. Universal Chocking Sign • Phase 2: (2-5 minutes). Patient will lose consciousness, decreased respirations and vital signs. • Phase 3: (Greater than 5 minutes.) Patient will be in cardiovascular arrest, and then death. PARTIAL AIRWAY OBSTRUCTION • A forceful cough often may be elicited from a victim with good air exchange. • Wheezing may be noted between coughs. • The victim with partial obstruction and good air exchange should be allowed to continue coughing and to breathe without any physical intervention by rescuers. • Those with poor air exchange exhibit weak, ineffectual cough reflexes and a characteristic “crowing” sound during inspiration. • Voice sounds may be absent or altered because the vocal cords cannot appose normally. BASIC AIRWAY MANEUVERS Head Tilt-Chin Lift Jaw Thrust ESTABLISHING AN EMERGENCY AIRWAY WHEN A PATIENT’S AIRWAY IS OBSTRUCTED • Establishment of a patent airway becomes the immediate goal of treatment. A variety of procedures exist to accomplish this goal. • Two procedures tracheostomy and cricothyrotomy require surgical intervention and thus considerable knowledge and technical skill to be carried out effectively. • A third procedure, which is nonsurgical, is the procedure of choice for the initial management of all obstructed airways when basic life support techniques prove inadequate. • This is the external subdiaphragmatic compression technique, known as the abdominal thrust, or the Heimlich maneuver. NONINVASIVE PROCEDURE: BACK BLOWS • The 2010 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care modified classification of victims of FBAO as follows: (1) The choking victim 1 year of age and older (child and adult) and (2) the infant. • Back slaps remain an integral part of the protocol for obstructedairway management in the infant. • When back slaps are performed on the infant, the infant is straddled over the rescuer’s arm with the head lower than the trunk and with the head supported by the rescuer’s firm hold on the infant’s jaw. • Using the heel of the hand, the rescuer delivers up to five back slaps forcefully between the infant’s shoulder blades while resting the other hand on the thigh. • Each slap should be delivered with sufficient force to attempt to dislodge the foreign body. NONINVASIVE PROCEDURE: ABDOMINAL THRUST (HEIMLICH MANEUVER) • Manual thrusts to the upper abdomen (Heimlich maneuver [abdominal thrust]) or lower chest (chest thrust) are designed to produce a rapid increase in intrathoracic pressure, acting as an artificial cough that can help dislodge a foreign body. • The objective of each single thrust should be to relieve the obstruction. • Today this maneuver is the recommended primary technique for relief of foreign body airway obstruction in victims 1 year of age and older. NONINVASIVE PROCEDURE: CHEST THRUST • The chest thrust is an alternative—in special situations only—to the Heimlich maneuver as a technique for opening an obstructed airway. • There is no substantial difference in the effectiveness of these techniques when performed properly. • Chest thrusts should be used for obese patients if the rescuer is unable to encircle the victim’s abdomen. • If the choking victim is in the late stages of pregnancy, the rescuer should use chest thrusts instead of abdominal thrusts. INVASIVE PROCEDURE: CRICOTHYROTOMY • Cricothyroid membrane puncture (cricothyrotomy) involves establishment of an opening in the airway at the level of the cricothyroid membrane and is an accepted means of emergency airway access. • Cricothyrotomy is easier and quicker than tracheostomy, and the incidence of complications is significantly lower. • In addition, no significant anatomic structures are found near the cricothyroid membrane. HYPERVENTILATION • Hyperventilation is defined as ventilation in excess of that required to maintain normal blood PaO2 (arterial oxygen [O2] tension) and PaCO2 (arterial carbon dioxide [CO2] tension) • It is produced by an increase in the frequency or depth of respiration, or both. • Hyperventilation, a not uncommon emergency in the dental office, almost always is a result of extreme anxiety. • In most instances the hyperventilating patient remains conscious throughout the episode. • Loss of consciousness secondary to hyperventilation is extremely rare. • Hyperventilation more commonly produces an altered level of consciousness; victims report feeling faint, lightheaded, or both but do not lose consciousness. HYPERVENTILATION • Acute anxiety is the most common predisposing factor for hyperventilation. • Hyperventilation can be prevented most effectively through the recognition and management of anxiety. • The vital signs of apprehensive patients may deviate from the normal, or baseline, values for that individual. • Blood pressure is elevated, with the systolic pressure rising more than the diastolic. The heart rate is increased, potentially to a degree significantly higher than the baseline. • In addition, the patient’s respiratory rate increases above the normal adult rate of 14 to 18 breaths per minute, whereas the depth of respiration may be either deeper or more shallow than normal. HYPERVENTILATION • As hyperventilation continues, the chemical composition of the blood changes, and the patient begins to feel lightheaded or giddy, which intensifies the apprehension even more. • Increased apprehension leads to an increase in the severity of the episode, and a vicious cycle begins. • The goal in managing this situation is to break this cycle. • Normal respiratory rate for the adult is 14 to 18 breaths per minute. • During hyperventilation the respiratory rate may easily exceed 25 to 30 breaths per minute, even approaching 50 to 60 breaths per minute. HYPERVENTILATION MANAGEMENT • The management of hyperventilation is directed at correcting the respiratory problem and reducing the patient’s anxiety level. • Step 1: Remove the presumed cause of anxiety • Step 2: Position the patient in an upright position • Step 3: Remove any foreign materials from the mouth • Step 4: Calm the patient, speak in a relaxed manner and have the patient start taking slower breaths • Step 5: Correct the Respiratory Alkalosis (increased in PaCO2) by having the patient breath in and out of a paper bag or cupped hands. ASTHMA • Extreme sensitivity of the airways characterized by: • • • • Abnormal generation and clearance of secretions Abnormally sensitive cough reflex Extrinsic • • • • Increased contractile response of the respiratory smooth muscle Also known as Allergic Asthma affects 50% pf patients with asthma. In children and young adults with an inherited allergic predisposition Approximately 50% of asthmatic children become asymptomatic before reaching adulthood Intrinsic • • • • • • Adults over 35yo Non-allergic factors are causative Smoking, Respiratory infection, physical exertion, air pollution, occupational chemical exposure. Usually without history of allergies Viral illnesses worsen airway reactivity of asthmatic and non-asthmatic pts Psychological and physiologic stress can contribute to episodes PREDISPOSING FACTORS FOR ASTHMA ASTHMA CLASSIFICATION MIXED: A COMBINATION OF INTRINSIC AND EXTRINSIC ASTHMA MAJOR PRECIPITATING FACTOR IS INFECTION, ESPECIALLY RESPIRATORY TRACT INFECTIONS STATUS ASTHMATICUS Most severe form of Asthma Airway distress that cannot be corrected with Albuterol Rescue inhaler True medical emergency Can be rapidly fatal QUESTIONS TO ASK PATIENTS WITH ASTHMA DO YOU HAVE OR HAVE YOU HAD ASTHMA, TUBERCULOSIS, EMPHYSEMA, OR OTHER LUNG DISEASES? DO YOU HAVE OR HAVE YOU HAD ALLERGIES TO DRUGS, FOODS, MEDICATIONS, LATEX? Common cause of asthma attacks is allergens (extrinsic) Singulair – for severe allergies ARE YOU TAKING DRUGS, MEDICATIONS, OVER-THE-COUNTER MEDICINES (INCLUDING ASPIRIN), OR NATURAL REMEDIES? Inhalers: Rescue (Albuterol) vs Daily DETERMINING THE SEVERITY ASTHMA What causes you to wheeze? When was your last asthma attack? Have you ever had an attack you couldn’t break with your inhaler? Have you ever been hospitalized for your Asthma? Do you use your other inhalers every day like you are supposed to? MEDICAL MANAGEMENT OF ASTHMA: DRUG THERAPIES ASTHMA: MEDICATIONS SHORT ACTING BETA-2 AGONISTS – Albuterol, Rescue inhaler, Bronchodilator • Used to prevent wheezing or asthma attacks when patient will be exposed to an exacerbating factor. • • • • Used to break asthma attack Short Acting – 3 to 6 hours – peak action at 2 hours Can use repeatedly for an asthma attack If 3 doses does not break attack call for emergency squad ASTHMA: MEDICATIONS INHALED CORTICOSTEROIDS Fluticasone, Mometasone, Budesonide • • • Reduce airway inflammation therefore reducing airway reactivity Must be used daily to be effective Reduce the risk of exacerbations due to triggers ASTHMA MEDICATIONS • Immune Modulators • Cromolyn sodium – used in mild to moderate Asthma • Blocks Histamine release from Mast cells • Used preventatively for Asthma correlated with allergens • Montelukast – Singulair, Leukotriene modifier that opposed the release and/or influence of inflammatory mediators. ASTHMA MEDICATIONS LONG ACTING BETA-2 AGONISTS Salmeterol, Formoterol • • More severe Asthma • Combo inhalers with corticosteroids such as Symbicort, Dulera, Advair Usually used in combination with other therapies DENTAL CONSIDERATIONS • MAINTAIN THE PATIENT’S PULMONARY STATUS AS CLOSE TO NORMAL AS POSSIBLE • PREVENT ACUTE EPISODES DURING TREATMENT • SPECIFICALLY: ALLEVIATE EMOTIONAL STRESS AND ANXIETY. PATIENT MAY NEED SEDATION SUCH AS NITROUS OXIDE OR IV SEDATION • BETWEEN 3% AND 19% OF ASTHMATIC PATIENTS ARE SENSITIVE TO ASPIRIN ADMINISTRATION • AMERICAN SOCIETY OF ANESTHESIOLOGISTS (ASA) PHYSICAL CLASSIFICATION SYSTEM • • Well-Controlled patient is ASA 2 • Patients that have symptoms at rest are ASA 4 Patients that have acute episodes or have required emergency medical care or hospitalizations are ASA 3 BREATHING INSPIRATION VS EXPIRATION • DIFFERENT TYPES OF INFLAMMATORY DISEASES AND OBSTRUCTIONS AFFECT DIFFERENT PHASES OF BREATHING • WHEEZING IS THE SOUND PRODUCED BY TRYING TO PULL AIR INTO AIRWAYS WITH INCREASING OBSTRUCTION/INFILTRATES/NARROWING • ASTHMA ATTACKS ARE PRIMARILY AN OBSTRUCTION OF EXPIRATION – AIR TRAPPING IN LUNGS • AS OBSTRUCTION CONTINUES EXCESSIVE ENERGY IS SPENT TRYING TO EXHALE TRAPPED AIR • RESPIRATORY FAILURE ENSUES DUE TO MUSCLE FATIGUE OF ACCESSORY MUSCLES OF BREATHING HOW TO RECOGNIZE RESPIRATORY DISTRESS ESPECIALLY CONCERNING IS USE OF ACCESSORY MUSCLES TO BREATH/CHEST FLARING “TRIPOD” POSITION LEANING FORWARD WITH HANDS ON KNEES OPEN MOUTH BREATHING NASAL FLARING ESPECIALLY IN CHILDREN BRONCHOSPASM • SMOOTH MUSCLE IS PRESENT THROUGHOUT THE ENTIRE TRACHEOBRONCHIAL TREE. • BRONCHIAL SMOOTH MUSCLE TONE IS REGULATED BY THE VAGUS NERVE, WHICH WHEN STIMULATED, CAUSES CONSTRUCTION (BRONCHOSPASM), AND BY THE SYMPATHETIC NERVOUS SYSTEM, WHICH PRODUCES DILATION (BRONCHODILATION) • IN NON-ASTHMATIC PATIENTS, BRONCHIAL SMOOTH MUSCLE PROTECTS THE LUNGS FROM FOREIGN STIMULI (BRONCHIAL SMOOTH MUSCLE CONSTRICTION) • IN THE ASTHMATIC, THE RESPONSE IS EXAGGERATED (INCREASED CONSTRUCTION) PRODUCING CLINICAL SIGNS AND SYMPTOMS OF RESPIRATORY DISTRESS. • ASTHMATIC PATIENTS ALSO HAVE BRONCHIAL WALL EDEMA AND HYPERSECRETION OF MUCUS GRANDS. MANAGEMENT OF ASTHMA ATTACK