U P P E R R E S P I R A T O R Y T R A C T D I S O R D E R S

Upper Respiratory System Overview and Principles of Clinical Feedback

• Course and Survey Feedback Principles:

  • Midterm just-in-time surveys serve to optimize instruction and course structure.
  • Constructive criticism requires identifying specific areas needing improvement alongside practical suggestions for resolution (e.g., avoiding vague negative statements such as "I hate Doctor Cobb" which offer no actionable insight into student dissatisfaction or pedagogical improvement).

• Anatomical Division of the Respiratory System:

  • Upper Respiratory Tract: Anatomically located above the sternal notch and clavicles (above the glottis/epiglottis).
  • Lower Respiratory Tract: Anatomically located below the sternal notch, extending into the trachea, bronchi, bronchioles, and alveoli.

Upper Respiratory System Physiology and Pathophysiology

• Anatomical Structures and Functions:

  • Pharynx: Serves as a shared passageway for swallowed food/liquids and inhaled air entering the digestive system and lower respiratory tract, respectively.
  • Larynx: Houses the vocal cords for vocalization/speech production and the epiglottis.
  • Epiglottis: A flap-like cartilaginous structure that folds downward over the vocal cords and larynx during swallowing to prevent aspiration of foreign material into the lungs, thereby preventing aspiration pneumonia.
  • Nasal Passages and Paranasal Sinuses: Responsible for warming, filtering, and humidifying air. Sinuses can become fluid-filled during infectious or inflammatory states, causing congestion and severe pressure pain.

• Pathophysiology of the Common Cold (Viral Upper Respiratory Infection):

  • Host Defense Mechanism: The immune response recruits white blood cells (WBCs) to the upper respiratory mucosa, stimulating the secretion of thick mucus to trap viral pathogens and prevent pulmonary migration.
  • Sore Throat (Pharyngitis): Primarily caused by postnasal drip draining down the posterior pharynx rather than primary bacterial infection (e.g., streptococcal pharyngitis). Pharynx appears red and swollen.
  • Cough: Triggered when postnasal mucus contacts throat cough receptors. Coughing serves as a protective mechanism to expel trapped pathogens and secretions before they enter the lower airways.
  • Sinus Pressure and Headache: Caused by fluid accumulation and inflammatory edema within the frontal and maxillary sinuses across the forehead and cheeks.
  • Fever Threshold: Body temperature of $100.4^\text{o}\text{F}$ ($38.0^\text{o}\text{C}$) or higher constitutes a clinical fever. Low-grade fevers may accompany viral colds.
  • Associated Manifestations: Fatigue, hoarse voice (occurring during tissue recovery/healing), and painful, swollen cervical and submandibular lymph nodes.
  • Non-Pharmacological Relief: Systemic hydration (drinking abundant fluids to thin secretions), warm saltwater gargles (alleviates throat inflammation and discomfort), and over-the-counter (OTC) analgesics/antipyretics.

• Pathophysiology of Allergic Rhinitis:

  • Etiology: Non-infectious, immune-mediated (Type I hypersensitivity) response triggered by environmental allergens (e.g., ragweed during fall; tree/grass pollen during spring).
  • Histamine Response: Exposure to allergens induces massive IgE-mediated histamine release from mast cells.
  • Vasodilation: Histamine causes widespread nasal vasodilation, resulting in marked mucosal swelling and nasal obstruction.
  • Vascular Permeability: Increased capillary permeability yields watery nasal drainage (rhinorrhea).
  • Nerve Stimulation: Direct stimulation of sensory nerve endings by histamine produces intense sneezing and itching of the eyes, nose, and palate.
  • Postnasal Drip: Stimulation of mucous glands yields clear postnasal drainage and throat irritation.
  • Clinical Differentiating Features:
    • Common Cold: Viral origin, self-limiting duration ($5\,\text{days}$ to $7\,\text{days}$), may feature fever, typically lacks eye itching.
    • Allergic Rhinitis: Chronic/recurrent duration tied to allergen exposure, lacks fever, characterized by prominent ocular itching and clear rhinorrhea.

Analgesic and Antipyretic Therapy: Acetaminophen

• Acetaminophen (Tylenol):
  • Indications: Relief of mild-to-moderate pain (e.g., body aches, facial/sinus pressure) and reduction of fever ($\ge 100.4^\text{o}\text{F}$).
  • Maximum Daily Dose Limit: Must not exceed $4\,\text{g/day}$ ($4000\,\text{mg/day}$) across all combined sources to prevent acute liver failure.
  • Hepatotoxicity and Monitoring:
    • Requires baseline and periodic monitoring of liver function tests (LFTs), specifically AST and ALT.
    • Clinical Signs of Liver Damage: Jaundice (yellowing of skin and sclera), pale/clay-colored stools, ascites (abdominal swelling from fluid retention), right upper quadrant abdominal pain.
  • Overdose Risk in Over-the-Counter (OTC) Products:
    • Many OTC multi-symptom cold/flu formulations (e.g., TheraFlu, DayQuil, Mucinex FastMax) contain combination formulations featuring $3$ to $4$ active ingredients, including acetaminophen.
    • Clients taking multiple OTC cold preparations concurrently face severe risks of inadvertent toxicity.
    • Clinical Case Highlight: An ICU patient who intentionally ingested an acetaminophen overdose developed permanent structural liver damage despite calling EMS shortly after ingestion.

Anticholinergic Side Effect Profile

• Anticholinergic Toxicity Mnemonic:

  • "Can't see, can't pee, can't spit, can't poop."

• Physiological Manifestations:

  • "Can't see": Mydriasis (pupillary dilation) and loss of accommodation, resulting in blurry vision due to drying of ocular lubrication.
  • "Can't pee": Urinary retention secondary to detrusor muscle relaxation and internal urethral sphincter constriction.
  • "Can't spit": Xerostomia (dry mouth) caused by inhibition of salivary gland secretions.
  • "Can't poop": Decreased gastrointestinal motility and intestinal secretions, producing severe constipation.

Antihistamine Pharmacotherapy

• First-Generation Antihistamines: Diphenhydramine (Benadryl):

  • Mechanism of Action: Non-selectively blocks central and peripheral Histamine-1 ($H_1$) receptors, competing with histamine to suppress vasodilation, capillary permeability, rhinorrhea, and sneezing. Crosses the blood-brain barrier.
  • Routes of Administration: Oral (PO), Intramuscular (IM), Intravenous (IV).
  • Adverse Effects: Profound CNS depression/sedation, residual dizziness, severe anticholinergic effects (dry mouth, urinary retention, constipation, blurred vision).
  • Drug Interactions: Alcohol and other CNS depressants (e.g., benzodiazepines, opioids), which produce additive, life-threatening CNS depression.
  • Contraindications and Precautions:
    • Newborns and Breastfeeding Females: Dries up glandular secretions, severely reducing or stopping breast milk supply.
    • Older Adults: High sensitivity to central effects, prolonged drug elimination due to age-related renal/hepatic decline; high risk for extreme sedation, cognitive delirium, and falls.
    • Pediatric Clients: High risk of profound CNS effects or paradoxical excitation; no established safe dosing guidelines for children under $2\,\text{years}$ of age.
    • Narrow-Angle Glaucoma: Anticholinergic ocular effects increase intraocular pressure.
    • Benign Prostatic Hyperplasia (BPH) / Enlarged Prostate: Anticholinergic urinary retention exacerbates bladder outlet obstruction.
  • Client Education: Administer at bedtime; strictly avoid driving, operating machinery, climbing ladders, or traveling (e.g., road trips); report severe palpitations or visual changes; avoid all alcohol intake.

• Second-Generation Antihistamines: Cetirizine (Zyrtec):

  • Mechanism of Action: Selectively blocks peripheral $H_1$ receptors. Poor penetration of the blood-brain barrier.
  • Key Clinical Advantages: Significantly less CNS sedation and drowsiness compared to diphenhydramine.
  • Clinical Role Comparison: Diphenhydramine remains the drug of choice for severe acute allergic reactions or anaphylaxis due to the availability of parenteral (IV/IM) formulations; cetirizine is preferred for daily chronic allergic rhinitis.
  • Adverse Effects and Considerations: Low incidence of mild sedation (clients should evaluate individual tolerance prior to driving), mild anticholinergic effects, lactation suppression (contraindicated/caution in breastfeeding).
  • Target Populations: Preferred antihistamine agent for older adults and pediatric clients needing daily therapy due to lower fall and cognitive risk profiles.

Antitussive Pharmacotherapy

• Opioid Antitussives: Codeine:

  • Mechanism of Action: Acts directly on the medullary cough center in the brainstem, binding to mu-opioid receptors to suppress the cough reflex pathway and decrease coughing frequency and intensity.
  • Indications: Intractable, painful, non-productive coughs causing severe rib pain (costochondritis) or profound exhaustion and sleep deprivation.
  • Pre-Administration and Post-Administration Assessments:
    • Measure baseline respiratory rate, oxygen saturation ($SpO_2$), heart rate, blood pressure, and sedation level.
    • Perform and document pain/cough reassessment exactly $30\,\text{minutes}$ following oral administration.
  • Adverse Effects: Respiratory depression, CNS depression, severe drowsiness, hypotension, bradycardia, constipation, nausea, vomiting, dizziness.
  • Safety Precautions: Keep side rails elevated, ensure the call light is within immediate reach, assist with ambulation, measure oral liquid doses precisely using a calibrated medicine cup, administer with food or milk to reduce gastric upset.
  • Contraindications and Cautions:
    • Children Under $12\,\text{Years}$ of Age: High risk of fatal respiratory depression.
    • Asthma and Chronic Obstructive Pulmonary Disease (COPD): Suppressing the cough reflex prevents clearing of bronchial secretions, causing mucus plugging and secondary pneumonia.
    • Post-Tonsillectomy or Adenoidectomy: Increased bleeding and airway complication risks.
    • Head Trauma or Increased Intracranial Pressure (ICP): CNS depression masks neurological changes and worsens hypercapnia.
    • Substance Misuse History: Potential for abuse and dependence.
  • Antidote: Naloxone (opioid antagonist) for life-threatening respiratory depression or unresponsiveness.

• Non-Opioid Antitussives: Dextromethorphan (Robitussin):

  • Mechanism of Action: Directly suppresses the medullary cough center in the brainstem without binding to opioid receptors.
  • Indication: Short-term management of dry, non-productive coughs caused by throat/postnasal irritation.
  • Administration Requirement: Avoid drinking liquids immediately following oral liquid administration to prevent washing away or diluting the mucosal coating/medication.
  • Adverse Effects: Mild drowsiness, dizziness, nausea, euphoria, nystagmus, mydriasis. Serious/rare: Serotonin syndrome, hallucinations, extreme agitation.
  • Drug Interactions: Monoamine Oxidase Inhibitors (MAOIs), Selective Serotonin Reuptake Inhibitors (SSRIs), and other CNS depressants. Concurrent use with SSRIs/MAOIs significantly increases serotonin syndrome risk.
  • Contraindications and Cautions:
    • Productive Cough: Must not be suppressed.
    • Children Under $4\,\text{Years}$ of Age: Contraindicated. Non-pharmacological measures must be used (nasal saline flushes, cool/warm-mist humidifiers, steam exposure from a hot shower).
    • Diabetes Mellitus: Standard cough syrups contain high sugar content to mask bitterness, causing significant blood glucose elevation (especially during illness stress). Low-sugar/sugar-free formulations must be selected.
    • Hepatic Impairment, Older Adults, and Lactation.

Decongestant Pharmacotherapy

• Decongestants: Phenylephrine and Pseudoephedrine:
  • Mechanism of Action: Stimulates Alpha-1 ($\alpha_1$) adrenergic receptors on vascular smooth muscle, triggering local vasoconstriction of dilated nasal mucosal blood vessels to reduce swelling and edema.
  • Indications: Nasal congestion secondary to common colds or allergic rhinitis.
  • Strict Maximum Duration Limits:
    • Intranasal Spray (e.g., Afrin / Phenylephrine): Maximum limit of $5\,\text{days}$. Usage beyond $5\,\text{days}$ induces rebound congestion (rhinitis medicamentosa), resulting in persistent severe tissue swelling.
    • Oral (PO) Route: Maximum limit of $7\,\text{days}$. Symptoms persisting beyond $7\,\text{days}$ necessitate medical evaluation for secondary bacterial infections.
  • Adverse Effects: Severe hypertension, reflex bradycardia, cardiac dysrhythmias, exacerbation of angina or heart failure, CNS stimulation (restlessness, insomnia).
  • Drug Interactions: MAOIs (within $14\,\text{days}$), other sympathomimetics/stimulants, and caffeine (exacerbates blood pressure and heart rate elevations).
  • Contraindications: Severe hypertension, coronary artery disease, cardiac dysrhythmias, first trimester of pregnancy (reduces uteroplacental perfusion), concurrent MAOI therapy.
  • Nasal Spray Administration Technique: Point the spray nozzle slightly outward toward the lateral nasal wall/blood vessels rather than straight up or backward down the throat to optimize vascular contact and prevent swallowing.
  • Regulatory and Efficacy Differences:
    • Pseudoephedrine: Restricted behind the pharmacy counter requiring driver's license ID verification due to misuse as a precursor for illegal methamphetamine synthesis.
    • Phenylephrine: Available OTC without ID verification; however, FDA panels note oral phenylephrine is substantially less clinically effective than oral pseudoephedrine (though highly effective intranasally).
    • Hypertension Alternative: Formulations such as Coricidin HBP (containing acetaminophen and chlorpheniramine without adrenergic decongestants) are designed for hypertensive clients.

Expectorants and Mucolytics

• Expectorants: Guaifenesin (Mucinex):

  • Mechanism of Action: Decreases mucus viscosity (thickness) and increases respiratory tract fluid volume, allowing dry or trapped bronchial mucus to be coughed up more effectively. Does not suppress the cough reflex.
  • Indications: Respiratory disorders characterized by thick, tenacious mucus and non-productive or poorly productive coughs.
  • Administration Protocols: Take each dose with a full glass ($8\,\text{oz}$) of water. Maintain high daily systemic fluid intake to facilitate mucokinesis.
  • Maximum Duration Limit: Maximum $7\,\text{days}$ of continuous use without medical reassessment.
  • Adverse Effects: Gastrointestinal discomfort, nausea, dry mouth, dizziness, headache.
  • Cautions: Renal impairment (monitor BUN, serum creatinine, and urine output for oliguria/dark concentrated urine).
  • Clinical Misconceptions: Guaifenesin thins airway mucus to aid expectoration; it does not directly relieve nasal vascular congestion.

• Mucolytics: Acetylcysteine (Mucomyst):

  • Mechanism of Action: Cleaves disulfide bonds in mucoproteins, directly liquefying extremely thick, tenacious airway secretions.
  • Indications:
    • Respiratory: Adjunctive therapy for severe, viscous mucus in chronic pulmonary conditions (e.g., cystic fibrosis, chronic bronchitis/COPD).
    • Toxicology: Antidote for acute acetaminophen hepatotoxicity (given PO or IV).
  • Routes of Administration: Inhalation (nebulizer), Oral (PO), Intravenous (IV).
  • Adverse Effects and Nursing Interventions:
    • Rotten Egg Odor: Nebulized formulations release a strong sulfur odor resembling rotten eggs, often triggering severe nausea or vomiting.
    • Antiemetic Measures: Administer prophylactic antiemetics or provide alcohol swab inhalation (sniffing isopropyl alcohol wipes) to control nausea.
    • Airway Reactivity: Risk of acute bronchospasm, chest tightness, wheezing, and dyspnea, particularly in clients with asthma.
    • IV Administration Risks: High risk of severe anaphylactoid reactions and acute bronchospasm; requires continuous monitoring of respiratory status and $SpO_2$.
  • Drug Interactions: Oral acetylcysteine inactivates and reduces the effectiveness of co-administered oral activated charcoal.

Clinical Decision-Making Exercises: "Dose or No Dose" Case Scenarios

• Scenario 1:

  • Patient Profile: $68\,\text{year-old}$ male with nasal congestion and sinus pressure for $4\,\text{days}$. History of hypertension; takes lisinopril daily.
  • Vitals/Assessment: BP $168/92\,\text{mmHg}$, HR $88\,\text{bpm}$, RR $18\,\text{breaths/min}$, Temp $99.1^\text{o}\text{F}$. Congested nasal mucosa, no respiratory distress.
  • Medication Order: Phenylephrine $10\,\text{mg}$ PO every $4\,\text{hours}$ PRN.
  • Decision: No Dose.
  • Rationale: Phenylephrine is an alpha-1 agonist causing systemic vasoconstriction, which worsens uncontrolled hypertension ($168/92\,\text{mmHg}$).

• Scenario 2:

  • Patient Profile: $73\,\text{year-old}$ female with allergic rhinitis. History of narrow-angle glaucoma and urinary retention; lives alone.
  • Vitals/Assessment: Sneezing, runny nose, reports feeling forgetful recently.
  • Medication Order: Diphenhydramine $25\,\text{mg}$ PO every $6\,\text{hours}$.
  • Decision: No Dose.
  • Rationale: Diphenhydramine possesses potent anticholinergic effects that exacerbate narrow-angle glaucoma and urinary retention, and increases fall and delirium risks in an elderly client living alone.

• Scenario 3:

  • Patient Profile: $36\,\text{year-old}$ female with cough and fatigue. History of major depressive disorder taking sertraline $100\,\text{mg}$ daily; recently started linezolid for a skin infection.
  • Vitals/Assessment: Temp $100.4^\text{o}\text{F}$, HR $104\,\text{bpm}$, BP $136/82\,\text{mmHg}$, RR $18\,\text{breaths/min}$. Dry cough, restless, agitated, jittery, diaphoretic, mild hand tremors.
  • Medication Order: Dextromethorphan syrup PRN for cough.
  • Decision: No Dose.
  • Rationale: Combining dextromethorphan with sertraline (SSRI) and linezolid (MAOI properties) severely increases the risk of precipitating or worsening life-threatening serotonin syndrome (manifested by agitation, diaphoresis, tachycardia, and tremors).

• Scenario 4:

  • Patient Profile: $52\,\text{year-old}$ male with cough and shortness of breath. $35\,\text{pack-year}$ smoking history, chronic bronchitis (COPD).
  • Vitals/Assessment: Temp $100.8^\text{o}\text{F}$, HR $102\,\text{bpm}$, RR $22\,\text{breaths/min}$, $SpO_2 = 92\%$ on room air. Thick yellow-green sputum, coarse bilateral crackles, productive cough every few minutes.
  • Medication Order: Codeine cough syrup PRN.
  • Decision: No Dose.
  • Rationale: Codeine suppresses the cough reflex in a client with chronic bronchitis (COPD) and a productive cough, leading to retained pulmonary secretions, mucus plugging, and secondary pneumonia.

• Scenario 5:

  • Patient Profile: $27\,\text{year-old}$ female with seasonal allergic rhinitis every spring. Works as a day-shift hospital nurse.
  • Vitals/Assessment: BP $118/72\,\text{mmHg}$, HR $74\,\text{bpm}$, RR $16\,\text{breaths/min}$. Sneezing, clear rhinorrhea, itchy eyes, no fever, lungs clear.
  • Medication Order: Cetirizine $10\,\text{mg}$ PO daily.
  • Decision: Dose.
  • Rationale: Cetirizine is a second-generation non-sedating antihistamine appropriate for allergic rhinitis symptoms that will not impair the client's cognitive or motor functioning during her nursing work shifts.

• Scenario 6:

  • Patient Profile: $56\,\text{year-old}$ male with fever and body aches. History of chronic alcohol use ($3$ to $4\,\text{drinks/day}$); taking OTC cold remedies for $2\,\text{days}$.
  • Vitals/Assessment: Temp $101.23^\text{o}\text{F}$, fatigue, mild right upper quadrant abdominal discomfort. BP $128/78\,\text{mmHg}$, HR $88\,\text{bpm}$, RR $18\,\text{breaths/min}$.
  • Laboratory Results: $AST = 165\,\text{U/L}$, $ALT = 182\,\text{U/L}$.
  • Medication Order: Acetaminophen $650\,\text{mg}$ PO for fever.
  • Decision: No Dose.
  • Rationale: The client exhibits elevated liver enzymes ($AST = 165\,\text{U/L}$, $ALT = 182\,\text{U/L}$), right upper quadrant pain, chronic alcohol intake, and prior OTC cold medication exposure, placing him at extreme risk for severe hepatotoxicity from acetaminophen.

• Scenario 7:

  • Patient Profile: $48\,\text{year-old}$ male with cough and chest congestion following an upper respiratory infection for $5\,\text{days}$. No chronic lung disease.
  • Vitals/Assessment: BP $124/80\,\text{mmHg}$, HR $82\,\text{bpm}$, RR $18\,\text{breaths/min}$, Temp $99.4^\text{o}\text{F}$. Frequent cough producing thick white sputum; reports difficulty expectorating mucus; scattered rhonchi on auscultation.
  • Medication Order: Guaifenesin $600\,\text{mg}$ PO every $12\,\text{hours}$.
  • Decision: Dose.
  • Rationale: Guaifenesin is indicated as an expectorant to decrease mucus viscosity and assist in clearing thick sputum in acute non-chronic respiratory infections; no contraindications exist.

• Scenario 8:

  • Patient Profile: $72\,\text{year-old}$ male with seasonal allergic rhinitis, Stage 4 chronic kidney disease, and benign prostatic hyperplasia (BPH) taking tamsulosin daily.
  • Vitals/Assessment: BP $132/78\,\text{mmHg}$, HR $80\,\text{bpm}$, RR $16\,\text{breaths/min}$. Sneezing, runny nose, itchy eyes; reports decreased urine output over the past $2\,\text{days}$.
  • Laboratory Results: Serum $Creatinine = 3.2\,\text{mg/dL}$, GFR = 25\,\text{mL/min/1.73m}^2$.\n * **Medication Order**: Cetirizine 10\,\text{mg} PO daily.\n * **Decision**: **No Dose**.\n * **Rationale**: The client has severe renal impairment (GFR = 25\,\text{mL/min/1.73m}^2$,$Creatinine = 3.2\,\text{mg/dL}), active oliguria, and BPH. Cetirizine requires renal dose adjustments and carries anticholinergic urinary retention risks that compound his clinical status.\n\n* **Scenario 9**:\n * **Patient Profile**: 62\,\text{year-old} female with cough, shortness of breath, and history of severe asthma with multiple prior hospitalizations for bronchospasm.\n * **Vitals/Assessment**: RR 26\,\text{breaths/min}$, HR$110\,\text{bpm}$,$SpO_2 = 90\% on room air. Thick mucus production, audible wheezing, dyspnea at rest, accessory muscle use.\n * **Medication Order**: Acetylcysteine nebulized treatment.\n * **Decision**: **No Dose**.\n * **Rationale**: Nebulized acetylcysteine can precipitate acute, life-threatening bronchospasms in clients with asthma, especially those currently presenting with active wheezing and respiratory distress.\n\n* **Scenario 10**:\n * **Patient Profile**: 46\,\text{year-old}$male with nasal congestion for$3\,\text{days}$. History of borderline hypertension (not on meds); drinks$3$to$4\,\text{cups} of coffee daily.\n * **Vitals/Assessment**: BP 138/88\,\text{mmHg}$, HR$92\,\text{bpm}$, RR$16\,\text{breaths/min}. Moderate nasal congestion, clear rhinorrhea, mild sinus pressure, no fever.\n * **Medication Order**: Phenylephrine 10\,\text{mg}$PO every$4\,\text{hours} PRN.\n * **Decision**: **Dose with Caution / Close Monitoring (Borderline Risk)**.\n * **Rationale**: While not strictly contraindicated since he is not diagnosed with severe uncontrolled hypertension, phenylephrine poses vasoconstrictive risks. He requires extensive education to reduce caffeine (a compounding stimulant), monitor blood pressure frequently, and report palpitations.\n\n* **Scenario 11**:\n * **Patient Profile**: 49\,\text{year-old}$female with persistent cough for$10\,\text{days} producing thick sputum. History of type 2 diabetes mellitus with poor glycemic control.\n * **Vitals/Assessment**: Temp 100.2^\text{o}\text{F}$, HR$90\,\text{bpm}$, RR$18\,\text{breaths/min}. Reports fatigue; denies chest pain.\n * **Medication Order**: Guaifenesin syrup PRN for cough.\n * **Decision**: **No Dose**.\n * **Rationale**: Standard liquid cough syrups contain high concentrations of sugar that exacerbate poor glycemic control in diabetic clients. Additionally, symptoms lasting 10\,\text{days}$exceed the$7\,\text{day} limit and require provider evaluation for underlying bacterial infection.\n\n* **Scenario 12**:\n * **Patient Profile**: 54\,\text{year-old} female with worsening cough and difficulty clearing secretions. History of chronic bronchitis; no history of asthma or drug allergies.\n * **Vitals/Assessment**: BP 126/80\,\text{mmHg}$, HR$88\,\text{bpm}$, RR$20\,\text{breaths/min}$,$SpO_2 = 95\% on room air. Thick, tenacious sputum, difficulty expectorating, coarse lower-lobe crackles, no wheezing. Labs normal.\n * **Medication Order**: Acetylcysteine nebulized treatment.\n * **Decision**: **Dose**.\n * **Rationale**: Acetylcysteine is indicated to break down thick, tenacious mucoprotein bonds in chronic bronchitis. With no history of asthma or active bronchospasm, the benefit of liquefying secretions outweighs the risk.\n\n* **Scenario 13**:\n * **Patient Profile**: 28\,\text{year-old} female with allergy symptoms. No chronic illnesses; social weekend alcohol use; works as a night-shift restaurant server.\n * **Vitals/Assessment**: BP 118/74\,\text{mmHg}$, HR$78\,\text{bpm}$, RR$16\,\text{breaths/min}. Sneezing, itchy eyes, runny nose; reports difficulty sleeping due to symptoms.\n * **Medication Order**: Diphenhydramine 25\,\text{mg}$PO every$6\,\text{hours}$$ PRN.
  • Decision: Dose with Education.
  • Rationale: Diphenhydramine is appropriate for allergic rhinitis and can assist with her reported sleep difficulties, provided she is educated never to take it prior to driving or starting her work shift, and to avoid alcohol co-ingestion.