Comprehensive Nursing Review: Med-Surg, Cardiac, and Electrolyte Emergencies

Course Logistics and Academic Policies

• Course Closing and Access:
      * The course will officially close on Monday once students begin taking the exam.
      * Students must retrieve any desired materials or content from the course site before Monday.
      * The course is scheduled to reopen on Thursday afternoon, likely around $03:00$.
      * Early reopening is considered a "gift," and late reopening is attributed to administrative stress.
• Concurrent Course Access:
      * Medical-Surgical (Med Surg), Obstetrics (OB), and Pathophysiology (Patho) courses are designed to reopen at the same time. Writing courses may also reopen then, though they are generally of less concern to students.
• Grade Release Policy:
      * Exam grades will not be released until Thursday.
      * Instructors (specifically Doctor Hurley) will not disclose individual grades even if students demonstrate high anxiety or "beg" in their offices.
      * Consistency is maintained because sharing information with one student leads to wider dissemination among the cohort.

Electrolyte Imbalances and Assessment Findings

• Case Study Introduction (Mr. Lee):
      * Symptoms: Vomiting and diarrhea for a couple of days; wife reports confusion.
      * Medications: Furosemide and Lisinopril.
      * Comorbidity Identification: Use of Furosemide and Lisinopril suggests hypertension, heart failure, or blood pressure issues.
      * Vital Signs: Blood pressure is $90/52$, Heart rate is $116$. Down in weight.
• Specific Electrolyte Manifestations:
      * Hypernatremia: Primarily associated with disorientation.
      * Hypokalemia: Associated with U waves on an ECG. (Note: ECG waves may appear peaked or non-peaked in various states).
      * Hypocalcemia: Associated with "tension" (positive Trousseau's or Chvostek's signs).
• Intravenous (IV) Fluid Classifications:
      * $2.5\%$ Dextrose (D2.5): Initially classified as hypertonic; however, once the dextrose is metabolized, the solution becomes hypotonic.
      * $0.45\%$ Sodium Chloride: Categorized as a hypotonic solution.
• Potassium Administration Safety Protocols:
      * Peripheral IV maximum rate: $10\,mEq$ per hour.
      * Central Line maximum rate: Up to $40\,mEq$ per hour.
      * Requires continuous telemetry monitoring if giving up to $40\,mEq$.
      * Potassium should be diluted; never given as a bolus.

Cardiovascular Dysrhythmias and Clinical Interventions

• Electrical Conduction Pathway:
      * The normal flow of electricity: SA node $\rightarrow$ AV node $\rightarrow$ Bundle of His $\rightarrow$ Purkinje fibers.
      * This pathway creates ventricular contraction.
• Ventricular Tachycardia (V-Tach):
      * Characterized by a wide QRS complex.
      * The pattern is consistent and predictable from complex to complex, despite appearing "ugly."
      * No clear P waves are present, indicating the atrium is not participating in regular conduction.
• Clinical Management of V-Tach:
      * Stable (With Pulse): Priority intervention is cardioversion.
      * Unstable (Pulseless): Priority interventions are CPR and defibrillation as soon as possible.
• Ventricular Fibrillation (V-Fib):
      * Described as chaotic with no "rhyme or reason" to the rhythm.
      * It is a shockable, pulseless rhythm.
      * Management involves immediate CPR and use of an AED/Defibrillator.
• Atrial Fibrillation (A-Fib) and Atrial Flutter:
      * Atrial Flutter: Notable for a "jagged saw-tooth" pattern. The ratio of atrial beats to QRS complexes can vary (e.g., $3:1$, $4:1$, or $5:1$).
      * Risk: The atrium does not fill or empty completely, causing stagnant, pooling blood. This significantly increases the risk for Pulmonary Embolism (PE) or stroke.
      * Intervention: Requires anticoagulation therapy.
• Premature Ventricular Contractions (PVCs):
      * Wide, "ugly" QRS complexes that appear early compared to the regular rhythm.
      * Multifocal PVCs: Look different from one another because the impulse originates from different spots.
      * Cause/Irritability factors: Hypoxia, abnormal potassium or magnesium levels, or fluid status issues.

Respiratory Management and Arterial Blood Gases (ABGs)

• Respiratory Acidosis:
      * One of the most common clinical findings.
      * Normal Bicarbonate ($HCO_3$) range: $22$ to $26$.
      * In acute scenarios, kidneys take hours to days to compensate; a bicarb value within the normal range (e.g., $23$) during an acute change indicates respiratory acidosis is likely uncompensated or partially compensated.
• Acute Respiratory Failure and Pulmonary Edema:
      * Clinical signs: Saturation at $82\%$ on $6$ liters of oxygen, crackles in lungs, breathlessness, and confusion.
      * Intervention: Lasix (Furosemide) administered via IV push for rapid diuresis to move fluid from the lungs into the bloodstream/kidneys.
      * Escalated care: Prepare for mechanical ventilation and intubation followed by a repeat ABG.
• Breathing and Perfusion:
      * Hypovolemia can cause rapid breathing. This is a delivery issue, not an oxygen availability issue. The body breathes faster to compensate for low tissue perfusion.
      * Respiratory rate is often the first "red flag" for worsening status.

Renal Function and Oncology-Related Electrolytes

• Acute Kidney Injury (AKI):
      * Presentation: Tall peaked T-waves, elevated potassium (Hyperkalemia).
      * Etiology: Can be caused by rapid deterioration of kidney function or dehydration (puking/diarrhea).
      * Management: Requires managing potassium levels above all else. For extreme elevations (e.g., in Tumor Lysis Syndrome), dialysis is necessary.
• Hyperkalemia in Clinical Practice:
      * One of the most common clinical occurrences alongside hypoglycemia.
      * Tumor Lysis Syndrome: Chemotherapy kills cells (good and bad). Cell destruction releases potassium (which lives abundantly inside cells) into the serum. This process continues even after chemotherapy administration ends.
• Antidiuretic Hormone (ADH) Dynamics:
      * Diabetes Insipidus (DI): Insufficient ADH leads to massive urination of water but few solutes. Results in very low specific gravity. Mnemonic: "In DI, you get dry and you can die."
      * Syndrome of Inappropriate Antidiuretic Hormone (SIADH): Excessive ADH leads to water retention. Results in concentrated urine with many solutes and very little water.

Cardiac Diagnostics and Post-Operative Care

• Cholesterol Lab Thresholds:
      * Total Cholesterol: Desired below $200$.
      * LDL: Desired below $100$.
      * HDL: Desired above $60$.
• Cardiac Catheterization (Percutaneous Coronary Intervention - PCI):
      * Pre-procedure: Check Creatinine levels to establish baseline kidney function before administering nephrotoxic contrast dye. Assess for shellfish/iodine allergy. Patients should ideally be NPO for $8$ hours, though emergencies may bypass this.
      * Post-procedure: Assess pedal pulses (specifically the femoral artery used for access) to ensure no clotting. Monitor the access site for bleeding (patients can bleed to death quickly from a major artery). Administer fluids to flush dye and prevent intra-renal injury.
• Nitroglycerin Test: Used to differentiate between a Myocardial Infarction (MI) and Angina. If symptoms and ECG changes resolve with Nitro, it is likely Angina.
• Medication Management:
      * Beta Blockers: Reduce contractility and block the Sympathetic Nervous System (SNS). Patients may feel exhausted during initial weeks because the heart cannot "squeeze harder or beat faster" in response to stress.
      * Anticoagulation: Mechanical heart valves require lifelong anticoagulation (e.g., Warfarin/Coumadin). Biologic valves typically do not. Newer drugs like Xarelto do not require frequent INR monitoring compared to Coumadin.

Musculoskeletal and Neurological Complications

• Buck's Extension Traction:
      * A form of skin traction (non-invasive).
      * Goal: Fatigues the large muscles around a joint (like the hip) to prevent muscle spasms and reduce pain until surgery can occur.
• ORIF (Open Reduction Internal Fixation):
      * Indicates the use of screws, plates, and foreign bodies to stabilize a fracture.
• Stroke and MRI Safety:
      * Classic stroke sign: New confusion and facial drooping.
      * MRI screening: Medical hardware is generally safe, but shrapnel or bullets are dangerous due to magnetic pull.
      * In acute stroke, a CAT scan is preferred over MRI because it is faster.

Questions & Discussion

• Question (Prioritization): Who do you see first?
      * Answer: The patient with unstable angina (unpredictable, unresolvable chest pain) takes priority over stable conditions like pericarditis where pain is expected.
• Question (Triage): Patient with heart rate of $40$?
      * Answer: This is a concern as it falls below the typical threshold of $50$ or $60$, suggesting poor perfusion.
• Question (MRI/Pace Makers): Do pacemakers interfere with MRIs or everyday electronics?
      * Answer: Modern pacemakers are generally safe around microwaves. Post-surgery, patients should avoid lifting the arm on the affected side for a month or two to allow the leads to scar into place. They should carry a business card identifying the device for airport security.
• Question (Hypertonic Solution Risks): Why are hypertonic solutions dangerous?
      * Answer: They cause rapid fluid shifts. In the pulmonary system, this can lead to "flash pulmonary edema" as fluid moves from the high concentration in the vessels to the lower concentration in the tissue/alveoli. They must be given slowly (e.g., $50-70\,cc/hr$) in controlled settings like the ICU.
• Question (Infection Risk): What is the highest risk factor for a UTI?
      * Answer: The presence of an indwelling catheter. The device allows bacteria to travel directly into the bladder. Catheters should be removed as soon as possible.
• Question (Aneurysm Response): What if a patient with a known aneurysm has back pain?
      * Answer: Immediately check blood pressure to assess intravascular status and potential rupture. Assessment (feeling for a mass) is secondary to vitals.
• Question (Infective Endocarditis): Why does it cause dyspnea?
      * Answer: Vegetations on the heart valves can break off (microemboli) and travel to the pulmonary system, acting like a Pulmonary Embolism (PE).