Respiratory Disorders and Management Flashcards

Key Respiratory Definitions

• Anoxia: Absence of oxygen.

• Apnea: The cessation of respiratory movements.

• Dyspnea: A subjective sense of shortness of breath.

• Hypernea: A level of ventilation that is greater than normal minute ventilation while precisely meeting metabolic demands.

• Hyperventilation: Ventilation that exceeds metabolic demands.

• Hypoventilation: Ventilation that fails to meet metabolic demands.

• Hypoxia: A deficiency of oxygen in the inspired air.

• Orthopnea: The inability to breathe except in an upright position.

• Tachypnea: A respiratory rate that is greater than normal.

• Torr: A unit of pressure equal to $1\,mm\,Hg$.

• Ventilation: The total volume of air exchanged per minute.

General Principles of Respiratory Difficulty

• Primary Factor of Obstruction: The tongue is the primary factor that produces airway obstruction during a loss of consciousness.

• Common Potential Causes:
      * Hyperventilation.
      * Vasopressure syncope.
      * Asthma.
      * Heart failure.
      * Hypoglycemia.

• Major Triggering Factor: Stress is the major factor leading to the acute exacerbation of respiratory disorders.

• Prevention Strategies:
      * Pretreatment evaluation.
      * Modification of dental therapy.
      * Stress reduction protocol.

Clinical Foundations and Pathophysiology

• Clinical Manifestations:
      * Manifestations vary depending on the specific cause.
      * The patient usually remains conscious.
      * The patient may develop acute anxiety.
      * The sounds heard during respiration depend on the underlying cause.

• Pathophysiology by Condition:
      * Asthma: Affects the bronchioles.
      * Heart Failure: Specifically related to pulmonary edema.
      * Hyperventilation: Psychogenic in nature and directly affects blood chemistry.
      * Acute Lower Airway Obstruction: Severity and symptoms depend upon where the object becomes lodged.

Management of Respiratory Difficulty

• Immediate Action Steps:
      1. Recognize the problem.
      2. Terminate the dental procedure.
      3. Position the patient.
      4. Begin Basic Life Support (BLS).
      5. Monitor vital signs.
      6. Manage specific signs and symptoms.
      7. Initiate definitive management.

• Basic Life Support (BLS) Protocol:
      1. Position the patient.
      2. Perform a head tilt.
      3. Assess airway and breathing.
      4. Perform the jaw thrust maneuver if indicated.
      5. Re-assess airway and breathing.
      6. Provide artificial ventilation if needed.

Foreign Body Airway Obstruction (FBAO)

• Occurrence: Objects "lost" in the pharynx are usually swallowed or coughed up. Sit-down, four-handed dentistry has increased the possibility of objects falling into the oropharyngeal area.

• Prevention: The use of a rubber dam and oral packing may prevent swallowing or aspirating objects in dentistry.

• Complications of Swallowed Objects:
      * Gastrointestinal (GI) blockage.
      * Abscess.
      * Perforation.
      * Peritonitis (inflammation in the lining of the abdomen).

• Management of an Object in the Oropharynx:
      1. Do not allow the patient to sit up.
      2. Position the head down and encourage coughing.
      3. Take radiographs to determine location (e.g., Panoramic radiograph/PAN).
      4. Determine if the location is abdominal rather than bronchial.
      5. Seek medical consultation.

• Management of an Object in the Trachea:
      1. Do not allow the patient to sit up.
      2. Place the patient in a head-down position.
      3. Encourage coughing.
      4. Administer back blows.
      5. Obtain a radiograph to determine location.
      6. Accompany the patient to the emergency room.
      7. Note: The probable location is the right bronchus.
      8. Removal via bronchoscopy or thoracoscopy.

Clinical Indicators of Obstructed Airway

• Signs of Obstruction:
      * Patient gasps for breath with great effort.
      * Suprasternal retraction.
      * No noise (in complete obstruction).
      * The patient grabs their throat.
      * Patient may panic and flee.

• Timelines:
      * Approximately $2\,\text{minutes}$ of consciousness after complete obstruction.
      * Brain damage occurs in $3$ to $5\,\text{minutes}$ without air.

• Initial Management:
      * External subdiaphragmatic compression (abdominal thrust/Heimlich maneuver).

• Management of Partial Obstruction:
      * If air exchange is good, leave the patient alone and encourage coughing.

• Signs of Poor Air Exchange:
      * Weak, ineffective cough.
      * High-pitched "crowing" sound.
      * Increased respiratory difficulty.
      * Ashen-gray skin.
      * Cyanosis of nail beds and mucous membranes.

• Manual Non-Invasive Techniques:
      * Back blows.
      * Manual thrusts.
      * Finger sweeps.

Surgical and Emergency Airways

• Tracheotomy:
      * A surgical procedure employed for long-term airway maintenance.
      * Not well suited for emergency airway establishment.

• Cricothyrotomy:
      * The preferred method for establishing emergency airways.
      * Easier, quicker, and associated with fewer complications.
      * Anatomy involved: Thyroid gland, Notch at cricothyroid membrane, "Adam's apple" (prominentia laryngeal), Vocal cords, Thyroid cartilage, and Cricoid cartilage.

• Additional Obstruction Management:
      * Administer oxygen.
      * Summon medical assistance.
      * Transport to an emergency facility.

Hyperventilation

• Definition: Ventilation in excess of that required to maintain normal blood $PaO_2$ and $PaCO_2$. It is characterized by an increase in the frequency and/or depth of respiration.

• Epidemiology: One of the most common emergencies in dental practice. Most common in ages $15$ to $40$, with no gender predilection.

• Causes:
      * Extreme anxiety (particularly in patients who attempt to hide fear).
      * Pain.
      * Metabolic acidosis.
      * Drug intoxication.
      * Hypercapnia.
      * Cirrhosis.
      * Organic CNS disorders.

• Consciousness: More commonly produces impaired consciousness rather than total unconsciousness.

• Prevention:
      * Recognize and manage anxiety.
      * Observe for signs of anxiety.
      * Monitor vital signs (often above baseline).
      * Utilize stress reduction protocol.

• Clinical Manifestations:
      * Tightness in the chest and feeling of suffocation.
      * Lightheadedness or giddiness.
      * Increased apprehension (which worsens the severity).
      * Palpitations.
      * Precordial discomfort.
      * Epigastric discomfort.
      * Numbness and tingling of extremities.
      * Muscular twitching.
      * Carpopedal tetany.
      * Possible loss of consciousness.
      * Respiration rate of $25$ to $30\,\text{breaths per minute}$.

• Pathophysiology:
      * Anxiety increases respiratory rate/depth and blood levels of circulating catecholamines.
      * Increased respiration leads to excessive "blowing off" of carbon dioxide ($CO_2$), increasing blood pH (Respiratory Alkalosis).
      * Reduced $PaCO_2$ to abnormally low levels (hypocapnia) causes vasoconstriction, leading to dizziness and increased coronary artery vascular resistance (chest pain).
      * Elevated catecholamines cause palpitations.
      * Decreased ionized calcium in the blood leads to neuromuscular irritability.

• Management:
      1. Terminate dental procedure.
      2. Position patient upright.
      3. Remove materials from the mouth.
      4. Calm the patient.
      5. Correct respiratory alkalosis using a brown paper bag; oxygen is NOT indicated.
      6. Drug management: Intravenous Diazepam or Midazolam if necessary.
      7. Follow-up: Determine the cause and treat anxiety via psychosedation.

Asthma

• Definition: A clinical state of hyperactivity of the tracheobronchial tree characterized by recurrent paroxysms of dyspnea and wheezing resulting from bronchospasm, bronchial wall edema, and hypersecretion of mucous glands.

• Types of Asthma:
      * Extrinsic (Allergic) Asthma: Common in children and young adults; inherited allergic disposition; Type I hypersensitivity reaction involving IgE antibodies; triggered by allergens; may become asymptomatic in adulthood or chronic.
      * Intrinsic Asthma: Typically in adults over $35$; triggered by nonallergic factors like infection; also known as idiopathic or infective asthma; symptoms occur between acute episodes; poorer prognosis.
      * Mixed Asthma: A combination of both extrinsic and intrinsic factors.
      * Status Asthmaticus: The most severe clinical form; a true medical emergency; non-responsive to usual therapy; can lead to death.

• Dental Management:
      * Prevent acute exacerbations.
      * Review medications and take a dialogue history.
      * Stress reduction protocol.
      * Contraindications: Barbiturates and narcotics are contraindicated.
      * Eliminate allergens from the office and avoid drugs that precipitate attacks.

• Clinical Manifestations of Episodes:
      * Mild: Gradual or sudden onset; chest congestion; coughing spells; wheezing; dyspnea; increased anxiety; elevated heart rate; normal to elevated blood pressure.
      * Severe: Intense dyspnea and orthopnea; cyanosis of mucous membranes/nail beds; perspiration; face/torso flushing; use of accessory muscles of respiration; soft tissue retraction; fatigue; mental confusion.

• Pathophysiology: Continuous hyperactivity of bronchi provoked by immune reactions or toxins/irritants. Stress, temperature, and infection are contributory. Airway resistance increases due to obstruction.

• Management:
      * Mild: Terminate therapy, position comfortably, administer bronchodilator (Epinephrine, Isoproterenol, or Metaproterenol).
      * Acute/Severe: Administer bronchodilator and oxygen; parental Epinephrine; intravenous Aminophylline and corticosteroids; summon medical assistance; allow full recovery before discharge.

Heart Failure and Pulmonary Edema

• Definitions and Classifications:
      * Heart Failure: Cardiac function abnormality where the heart fails to pump adequate blood volume for tissue requirements.
      * Left Heart Failure: Associated with pulmonary vascular congestion.
      * Right Heart Failure: Associated with venous and capillary engorgement.
      * Congestive Heart Failure (CHF): A combination of both left and right heart failure.
      * Pulmonary Edema: Acute condition with excess serous fluid in alveolar spaces/interstitial tissues; accompanied by extreme breathing difficulty.

• Predisposing Factors: Increased workload of the heart and damage to muscular walls (Hypertension, Coronary Artery Disease, Myocardial Infarction, cardiac valvular deficiencies).

• Clinical Signs/Symptoms:
      * Shortness of breath; Chest pain; Fatigue; Weight gain.
      * Ankle swelling; Nocturia (waking up to urinate); Using extra pillows for sleep (to address orthopnea).
      * Cardiac medications: Digitalis, diuretics.
      * Physical findings: Ashen-gray skin; Cyanotic membranes; Prominent jugular veins.

• Left Heart Failure Specifics: Weakness; Dyspnea; Cough/expectoration; Nocturia; Orthopnea; Paroxysmal nocturnal dyspnea (PND); Pale, sweating cold skin; Hyperventilation.

• Right Heart Failure Specifics: Systemic venous congestion; Peripheral (dependent) edema; Cyanosis; Prominent jugular veins; Hepatomegaly (liver engorgement) and Splenomegaly (spleen engorgement); Anorexia, nausea, vomiting; Insomnia and irritability.

• Acute Pulmonary Edema Specifics: Acute onset; Slight dry cough; Wheezing (termed "cardiac asthma"); Dyspnea/orthopnea; Feeling of suffocation; Frothy pink sputum.

• Management: Position upright; Administer oxygen; Monitor vital signs; Alleviate apprehension; Summon medical assistance.

Differential Diagnosis Clinical Correlations

• Age as an Indicator:
      * Under age $10$: likely Asthma.
      * Age $12$ to $40$: likely Hyperventilation or Asthma.
      * Age $50$ to $60$ (Men): likely Heart Failure.
      * Age $60$ to $70$ (Women): likely Heart Failure.

• Effect of Positioning:
      * Supine position worsens Heart Failure.
      * Asthma and Hyperventilation are generally not affected by positioning.

• Breath Sounds:
      * Wheezing: Asthma, PND, Pulmonary Edema, or partial airway obstruction.
      * Moist/Wet Respiration: Heart Failure or Acute Pulmonary Edema.

• Other Clinical Indicators:
      * Shortness of Breath: Present in all forms of respiratory difficulty.
      * Accessory Muscle Use: Asthma or Acute Pulmonary Edema.
      * Chest Pain: Hyperventilation.
      * Increased Vital Signs: Present in all cases of respiratory distress.

• Duration of Episodes:
      * Heart Failure: Improves with repositioning (unless pulmonary edema is present).
      * Asthma: Not terminated until the patient is medicated.
      * Hyperventilation: Manageable without drugs.