oxygen and perfusion

What is the definition of perfusion?

The flow of blood through arteries and capillaries delivering nutrients and oxygen to cells.

Name the four chambers of the heart.

Right atrium, Right ventricle, Left atrium, Left ventricle.

Which four valves control blood flow through the heart?

Tricuspid, Pulmonic, Mitral, Aortic.

List the components of the heart’s electrical pathway in order.

Sinoatrial (SA) node → Atrioventricular (AV) node → Bundle of His → Purkinje fibers.

During which phase do the ventricles contract to eject blood and what heart sound is produced?

Systole; it produces S1.

During which phase do the ventricles relax to fill with blood and what heart sound is produced?

Diastole; it produces S2.

In systemic circulation, what type of blood do arteries carry?

Oxygenated blood to the body.

In pulmonary circulation, what type of blood do veins carry?

Oxygenated blood back to the heart.

What is cardiac output (CO)?

The amount of blood pumped by the ventricles in one minute.

How does heart rate (HR) normally affect cardiac output?

If HR increases, cardiac output generally increases—unless HR exceeds 150 beats/min, which decreases filling time and CO.

Why is adequate cardiac output critical for tissue health?

Without sufficient CO, oxygen and nutrients cannot reach cells, leading to perfusion problems.

What complications can result from impaired perfusion?

Ischemia, cell injury, and cell death.

Name three health-related factors that negatively influence perfusion.

Obesity, atherosclerosis, and decreased tissue elasticity with aging.

Which common lifestyle behaviors reduce perfusion effectiveness?

Sedentary lifestyle, smoking, and vaping.

Give two examples of medications that can depress cardiopulmonary function.

Opioids and certain cardiac medications (e.g., beta-blockers).

Define ischemia.

Decreased oxygen supply related to insufficient blood flow, often caused by atherosclerosis.

What causes angina?

Pain resulting from an imbalance between the heart’s oxygen supply and demand.

List four advanced perfusion problems covered across the curriculum.

Heart failure, myocardial infarction (MI), cerebrovascular accident (CVA)/transient ischemic attack (TIA), pulmonary embolism.

Which vital assessments are prioritized when evaluating perfusion?

Full set of vital signs, system-specific assessments, pain, and changes from baseline.

What patient positions can improve cardiopulmonary perfusion?

High Fowler’s and orthopneic positions.

Identify four medications commonly anticipated for acute cardiopulmonary perfusion issues.

Oxygen, Morphine, Nitroglycerin, Aspirin (ASA).

When should CPR be initiated?

Only when a person has no detectable pulse.

Describe the CAB sequence used in CPR.

Compressions → Airway → Breathing.

What equipment should be obtained immediately during a cardiac arrest in a healthcare setting?

Crash cart and automated external defibrillator (AED).

Which interventions improve peripheral tissue perfusion?

Elevating legs, administering anticoagulants, using sequential compression devices (SCDs), and encouraging ambulation/leg exercises.

How is an SCD sleeve properly applied?

Wrap with a two-finger space between the sleeve and the leg; remove for assessment, bathing, or ambulation.

Which psychological factor can adversely affect perfusion?

Anxiety.

Why must nurses reassess vital signs after any perfusion intervention?

To evaluate the client’s response and determine if outcome criteria are met or if further action is required.

Pulse Oximetry (SpO₂)

Non-invasive monitoring technique that estimates arterial oxygen saturation continuously.

Hemoglobin Saturation

Percentage of hemoglobin binding sites in the bloodstream occupied by oxygen; may be normal even when hemoglobin level is low.

Spring-Tension Sensor

Reusable pulse-ox probe held in place by a clip; skin must be checked every 2 hours for pressure injury.

Adhesive Finger/Toe Sensor

Disposable stick-on pulse-ox probe; inspect skin at least every 4 hours for irritation.

Tissue Necrosis

Skin and underlying tissue death caused by prolonged pressure from sensors or probes.

Non-Disposable Sensor Cleaning

Decontaminating reusable pulse-ox probes per manufacturer’s instructions to prevent cross-infection.

Capillary Refill

Time for color to return to blanched nail bed; documented with pulse-ox reading to indicate peripheral perfusion.

Weak or Absent Signal

Pulse-ox display issue often caused by poor circulation, hypotension, cuffs, restraints, or cold extremity.

Vasoconstrictive Drugs

Medications that narrow blood vessels and can produce inaccurate SpO₂ readings.

Ear Oximetry Sensor

Specialized probe used on the pinna or lobe when fingers are unsuitable or perfusion is poor.

Peripheral Vascular Disease

Circulatory disorder that decreases arterial blood flow and may distort pulse-ox accuracy.

Nail Polish Interference

Dark or opaque varnish on nails that blocks light transmission and lowers reading reliability.

Intravascular Dyes

Agents such as methylene blue or indocyanine green that absorb light and falsely lower SpO₂ values.

Chronic Bronchitis & Emphysema

COPD conditions in which pulse oximetry can be less reliable.

Over-the-Counter Pulse Oximeter

Low-cost consumer device not FDA-reviewed and unsuitable for medical decision-making.

Forehead or Ear Sensor Advantage

Probe sites that give better readings than digits in patients with low cardiac output.

Oropharyngeal Suctioning

Removal of secretions from mouth and throat; may be delegated to trained assistive personnel.

Nasopharyngeal Suctioning

Sterile catheter insertion through nostril to remove upper airway secretions; uncomfortable and often prescribed.

Y-Port Suction Catheter

Sterile suction catheter with control port allowing intermittent suction during insertion and withdrawal.

Suction Pressure Limits

Maximum negative pressure: 150 mm Hg adults/adolescents, 125 mm Hg children, 100 mm Hg infants.

Hyperoxygenation

Temporary increase in supplemental O₂ before suctioning to prevent suction-induced hypoxemia.

Sterile Technique

Aseptic method used during nasopharyngeal suctioning to avoid introducing pathogens into airway.

Semi-Fowler Position

Head-of-bed elevated 30–45°; preferred for conscious patient during suctioning to ease breathing.

Lateral Position

Side-lying posture used for unconscious patients to prevent airway obstruction and promote secretion drainage.

Water-Soluble Lubricant

Gel applied to suction catheter tip to ease passage and reduce mucosal trauma.

Analgesic Premedication

Pain medicine administered prior to suctioning to decrease procedure-related discomfort.

Delegation Considerations

Decision process analyzing patient needs and staff qualifications before assigning suctioning to LPN/LVN or AP.

Personal Protective Equipment (PPE)

Gloves, mask, goggles, or face shield (N95 if indicated) worn to prevent exposure during suctioning.

Suction Kit Components

Includes sterile catheter, sterile gloves, sterile container, saline or water, lubricant, and connecting tubing.

Pulse Oximeter Reading < 93%

Indicates inadequate oxygenation; prompts assessment of tubing connection, flow-meter setting, and patient’s respiratory status.

Flow Meter

Device attached to an oxygen source that regulates the prescribed liter flow to a face mask or cannula.

Dyspnea

Subjective sensation of breathing difficulty; must be assessed when oxygen saturation drops or patient reports shortness of breath.

Face Mask Fit

Mask must seal snugly around the patient’s face to deliver the ordered oxygen concentration effectively.

Skin Breakdown Over Ears/Face/Head

Reddened areas caused by tight elastic bands; prevented by adequate padding and proper strap tension.

Oxygen Supports Combustion

Oxygen accelerates fire; no smoking and strict safety precautions are required wherever oxygen is in use.

Oxygen Concentrator

Electrical device that extracts oxygen from room air for continuous home therapy; must be grounded and kept ventilated.

Liquid Oxygen Tank

Portable home oxygen source containing liquefied O₂; requires secure, upright placement away from heat.

“No Smoking” Signs

Visible reminders placed in homes using oxygen to reduce fire risk.

Assistive Personnel (AP) Limitation

Tracheostomy care cannot be delegated to AP; may be assigned to LPN/LVN only in stable situations per policy.

Personal Protective Equipment (PPE)

Includes gloves, mask, goggles/face shield, N95 as indicated; protects staff during tracheostomy care and suctioning.

Outer Cannula

Permanent portion of a tracheostomy tube that remains in the stoma and holds the inner cannula.

Disposable Inner Cannula

Replaceable sterile insert that fits inside the outer cannula; removed and discarded during tracheostomy care.

Faceplate

Flange of the tracheostomy tube resting against the neck; must be stabilized during cannula changes to prevent trauma.

Sterile Normal Saline

Isotonic solution used to cleanse the stoma and surrounding skin without irritation.

Suction Catheter

Sterile tube inserted into the tracheostomy to remove secretions before cannula change, preventing airway blockage.

Semi-Fowler Position

Head-of-bed 30–45°; facilitates breathing and cannula access in conscious tracheostomy patients.

Hydrocolloid/Polyurethane Foam Dressing

Advanced dressing placed under the tracheostomy flange to reduce skin injury and may stay in place longer.

Tracheostomy Holder (Velcro Collar)

Adjustable strap securing the tracheostomy tube; should allow only two fingers between collar and neck.

Accidental Extubation

Unintentional removal of the tracheostomy tube, prevented by stabilizing the faceplate during collar changes.

Sterile Technique

Method maintaining object sterility; essential when handling new inner cannulas and cleansing tracheostomy sites.

Plastic Disposal Bag

Receptacle placed within reach to discard contaminated inner cannulas and dressings without leaving sterile field.

Grounding Electrical Equipment

Safety measure for oxygen concentrators to prevent sparks that could ignite oxygen-rich environments.

Smoke Detectors & Fire Extinguisher

Required home safety devices when oxygen therapy is present; local fire department should be notified.

Delegation Guidelines (Appendix A)

Framework used by nurses to decide if tracheostomy care tasks can be safely assigned to LPN/LVN based on patient stability.

Albuterol

A short-acting β2 bronchodilator given PO or by inhalation to relieve bronchospasm; may cause tremors, anxiety, or palpitations.

Theophylline (Aminophylline)

A xanthine bronchodilator administered PO, IV, or rectally; requires serum-level monitoring due to risk of tachycardia, nausea, and seizures.

Corticosteroids (e.g., Prednisone, Dexamethasone)

Anti-inflammatory agents used PO, IV, inhaled, or intranasal; can cause fluid retention, hyperglycemia, and mood swings.

Diphenhydramine

First-generation antihistamine (H1 receptor antagonist) taken PO; often causes drowsiness, dry mouth, and urinary retention.

Cetirizine

Second-generation antihistamine (H1 antagonist) taken PO; produces headache with minimal sedation and few anticholinergic effects.

Fexofenadine

Non-sedating antihistamine (H1 antagonist) taken PO; dries respiratory mucosa and may cause nausea.

Zafirlukast

Leukotriene receptor antagonist taken PO to prevent—not treat—asthma attacks; can raise liver enzymes.

Montelukast

Once-daily leukotriene receptor blocker for long-term asthma control; taken PO and not for acute bronchospasm.

Bronchodilator

Drug class that relaxes airway smooth muscle to improve airflow (e.g., albuterol, theophylline).

Antihistamine (H1-receptor antagonist)

Medication that blocks histamine-1 receptors to reduce allergy symptoms (e.g., diphenhydramine, cetirizine).

Leukotriene Receptor Antagonist

Medication that blocks leukotriene-mediated bronchoconstriction and inflammation (e.g., montelukast).

Low-Flow Oxygen Device

Equipment that delivers variable FiO₂; total inhaled oxygen depends on patient’s breathing pattern (e.g., nasal cannula, simple mask).

High-Flow Oxygen Device

Equipment that delivers a fixed, precise FiO₂ meeting or exceeding patient inspiratory demand (e.g., Venturi mask, high-flow nasal cannula).

Fraction of Inspired Oxygen (FiO₂)

Percentage of oxygen in the gas a patient inhales; typical room air FiO₂ is 21%.

Nasal Cannula

Low-flow tubing with two prongs supplying 1–6 L/min (≈24–44% FiO₂); check prong placement frequently.

Simple Face Mask

Low-flow mask delivering 5–8 L/min (≈40–60% FiO₂); minimum 5 L/min to flush exhaled CO₂.

Nonrebreather Mask

Low-flow mask with reservoir bag giving 10–15 L/min (≈80–95% FiO₂); valves must stay patent.

Venturi Mask

High-flow, fixed-performance mask that mixes air and O₂ through venturi barrels to deliver 24–40% FiO₂ precisely.