Study guide

Deeper Anatomy & Physiology

  • Upper Respiratory Tract

    • Function: Air preparation (warming, moistening, and filtering).
    • Key Players:
    • Cilia: Hair-like structures that filter out dust and debris.
    • Goblet Cells: Secrete mucus to trap dust and other particles.

  • Lower Respiratory Tract

    • Importance: Site of asthma pathology, mainly in the bronchi and bronchioles.

  • Gas Exchange

    • Location: Alveoli via pulmonary capillaries.

Specific Triggers & Host Factors

  • Host Factors:

    • Genetics: Genetic predisposition to asthma.
    • Obesity: Linked to poor prognosis in asthma patients.
    • Gender: More common in males before puberty, more common in females after puberty.

  • Environmental Irritants:

    • Examples:
    • Second-hand smoke
    • Burning leaves/trash
    • Household fragrances (e.g., candles, perfumes)

  • Allergic Sensitization:

    • Risk for Children Under 5: Those with allergies to peanuts, latex, or pet dander are at increased risk.

Critical Labs & Diagnostics (The Details)

  • ABG Expectations:

    • Early Attack:
    • Condition: Hyperventilation
    • Laboratory Results: Low $PaCO_2$, High $pH$
    • Late/Severe Attack:
    • Condition: Muscle fatigue
    • Laboratory Results: High $PaCO_2$, Low $pH$

  • Potassium Levels:

    • Concern: Frequent use of Albuterol (SABA) can cause hypokalemia (low potassium).
    • Monitoring: Nurses must monitor urea and electrolytes.

  • Peak Flow Monitoring:

    • Recommendation: Should be done daily, even when the client feels well, to establish a baseline.

Medication Delivery Nuances

  • Dry Powder Inhaler (DPI):

    • Technique: Requires a fast, deep breath; propellant not used.

  • Nebulizers (Soft Mist):

    • Function: Convert liquid into a slow-moving mist; useful for clients who cannot coordinate an MDI.

  • Spacer Use:

    • Purpose: Critical with MDIs to prevent Oral Candidiasis (Thrush) when corticosteroids are used.

Comorbidities to Watch

  • GERD:

    • Impact: Acid reflux can trigger asthma symptoms after large meals.

  • Vocal Cord Dysfunction (VCD):

    • Symptoms Mimicking Asthma: Wheezing/tightness but involves the upper airway.

  • Sleep Apnea (OSA):

    • Effect: Poor sleep quality worsens daytime asthma fatigue.

Nursing Priority Summary

  • Recognize Cues:
    • Restlessness and Anxiety: Think Hypoxia first.
    • Silent Chest: After a period of wheezing indicates the need for emergency intervention.

Defining Status Asthmaticus

  • Description: Medical emergency unresponsive to standard rescue inhalers.
    • Key Feature: Unresponsive to initial treatment.
    • Danger: Can quickly lead to acute ventilatory failure and death.

Pathophysiology: The Cellular Level

  • Involved Cells:

    • Mast cells, T lymphocytes, and epithelial cells.

  • Involved Chemicals:

    • Histamine, leukotrienes, and platelet-activating factors.

  • Mucus Plug Issue:

    • Hypertrophy of goblet cells and mucous glands leads to thick plugs that can result in asphyxia.

Clinical Manifestations (The Nursing "Cues")

  • Pulsus Paradoxus:

    • Drop in systolic blood pressure during inspiration due to extreme negative pressure in the chest.

  • Neurological Decline:

    • Indicators: Drowsiness and confusion suggest CO$_2$ buildup/hypercarbia.

  • Chest Asymmetry:

    • May indicate a collapsed lung (pneumothorax) or major plugging.

  • Vital Signs:

    • Tachycardia (fast heart rate) and tachypnea (fast breathing).

Critical Lab & Diagnostic Markers

  • Peak Flow (PEFR) & FEV:

    • Status asthmaticus confirmed if values are less than 50% of the client's personal best.

  • Potassium Monitoring:

    • Monitoring due to SABAs like Albuterol pushing potassium into cells and causing hypokalemia.

  • Acid-Base Shift:

    • Starts as Respiratory Alkalosis (breathing too fast, blowing off CO$_2$) and ends as Respiratory Acidosis (muscle fatigue, retaining CO$_2$), indicating imminent mechanical ventilation needs.

Specialized Treatments

  • Magnesium Sulfate:

    • Administered IV to relax smooth muscles in airways when other medications fail.

  • IV Fluids: Critical for managing obstructive sleep apnea (OSA).

Definition of OSA

  • Occurrence: Airway partially or completely collapses during sleep.
  • Cycle:
    • Obstruction → Decrease in blood oxygen/increase in CO$_2$ → Body arouses to reopen airway → Normal breathing resumes → Client falls back to deep sleep, cycle repeats.
  • Key Manifestation: Loud snoring followed by breathing cessation for 10 seconds or longer, typically ending with a loud snort.

Anatomy & Risk Factors

  • The Culprit: The base of the tongue commonly causing obstruction.
  • Major Risk Factor: Obesity (BMI > 30), due to fat deposits compressing the airway.
  • Other Factors: Large neck circumference, smoking, alcohol/sedative use, and male gender risk.

Diagnostic Standard for OSA

  • Polysomnography (PSG): The definitive test for diagnosing OSA.
    • Measures: EEG (brain waves), EMG (muscle tension), oxygen saturation, and ECG (heart rhythm).
    • Apnea-Hypopnea Index (AHI): Number of pauses per hour; moderate-to-severe OSA defined by $ ext{AHI} ext{ ≥ } 15$ episodes per hour.

Treatments &