 OXYGENATION & RESPIRATORY PHYSIOLOGY – STUDY NOTES

 KEY CONCEPTS
 RESPIRATORY PHYSIOLOGY

MODULE 14 

STRUCTURE & FUNCTION OF THE RESPIRATORY SYSTEM
VENTILATION, PERFUSION, AND DIFFUSION
 PULMONARY CIRCULATION

NURSING INTERVENTIONS TO PROMOTE 


RESPIRATORY GAS EXCHANGE
OXYGEN & CARBON DIOXIDE TRANSPORT

HEALTHY PHYSIOLOGIC RESPONSES 


REGULATION OF RESPIRATION
CARDIOVASCULAR PHYSIOLOGY
 CORONARY ARTERY CIRCULATION
 BLOOD FLOW REGULATION
 CONDUCTION SYSTEM
 FACTORS AFFECTING OXYGENATION
 CONDITIONS AFFECTING CHEST WALL MOVEMENT
 ALTERATIONS IN RESPIRATORY FUNCTIONING
 ALTERATIONS IN CARDIAC FUNCTIONING
 ALTERED CARDIAC OUTPUT
 IMPAIRED VALVULAR FUNCTION
 MYOCARDIAL ISCHEMIA
 ASSESSMENT
OXYGENATION & RESPIRATORY PHYSIOLOGY  NURSING DIAGNOSES
 IMPLEMENTATION
 ACUTE CARE INTERVENTIONS
 SUCTIONING TECHNIQUES
KEY CONCEPTS  TRACHEAL CARE
 SUCTIONING METHODS
 Oxygen is essential for sustaining life.  ARTIFICIAL AIRWAYS
 MAINTENANCE AND PROMOTION OF LUNG EXPANSION
 Blood oxygenation depends on:  MAINTENANCE AND PROMOTION OF OXYGENATION
 HOME OXYGEN THERAPY
o Ventilation (air movement in and out of the  RESTORATION OF CARDIOPULMONARY FUNCTIONING
 RESTORATIVE AND CONTINUING CARE
lungs)  FLUID, ELECTROLYTE, AND ACID-BASE BALANCE
 COMPONENTS OF FLUID BALANCE
o Perfusion (circulation of oxygenated blood to  FLUID IMBALANCES
tissues) 

ELECTROLYTE BALANCE
ELECTROLYTE IMBALANCES
o Transport of respiratory gases (exchange and 

ACID-BASE BALANCE
ACID-BASE IMBALANCES
movement of O₂ and CO₂)  NURSING DIAGNOSIS
 IMPLEMENTATION
 Neural & chemical regulators adjust the rate and  INTRAVENOUS (IV) THERAPY
 VASCULAR ACCESS DEVICES (VADS)
depth of respiration to meet tissue oxygen demands.  BLOOD TRANSFUSION
 RESTORATIVE CARE
 The cardiovascular system delivers oxygen to the
body and removes carbon dioxide.

RESPIRATORY PHYSIOLOGY
 Respiratory gas exchange occurs between the environment and the blood.
 Respiration = exchange of O₂ and CO₂ during cellular metabolism.
 Airways carry oxygen to the alveoli, where it is exchanged for carbon dioxide.
 Alveolar-capillary membrane:
o O₂ → blood
o CO₂ → alveoli (to be exhaled)

STRUCTURE & FUNCTION OF THE RESPIRATORY SYSTEM

 Gas movement in and out of lungs depends on pressure changes.
 Inspiration:
o Diaphragm & external intercostal muscles contract
o Creates negative pleural pressure → air drawn in
 Work of Breathing:
o Effort required to inhale/exhale
o Influenced by:
 Surfactant: prevents alveolar collapse
 Atelectasis: collapse of alveoli
 Compliance: lung stretchability
 Airway resistance: ease of airflow
 Lung Volumes:
o Tidal volume: normal breath
o Residual volume: air remaining after full exhalation
o Forced vital capacity: max air exhaled after deep inhalation

VENTILATION, PERFUSION, AND DIFFUSION

 Ventilation: movement of gases in and out of lungs
 Perfusion: cardiovascular system pumps oxygenated blood to tissues and returns deoxygenated blood to lungs
 Diffusion: exchange of gases (O₂ & CO₂) at alveolar and tissue levels

PULMONARY CIRCULATION
 Transports blood to/from alveolar-capillary membrane for gas exchange.

RESPIRATORY GAS EXCHANGE

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  Diffusion is the key process for O₂/CO₂ exchange in alveoli and tissues.

OXYGEN & CARBON DIOXIDE TRANSPORT

 Oxygen transport system involves both the lungs and cardiovascular system.
 Carbon Dioxide (CO₂):
o A byproduct of cellular metabolism
o Diffuses into RBCs
o Rapidly converted to carbonic acid (H₂CO₃)
o Carbonic acid dissociates into:
 Hydrogen ion (H⁺)
 Bicarbonate ion (HCO₃⁻)
o Hemoglobin buffers H⁺
o Bicarbonate (HCO₃⁻) diffuses into plasma

REGULATION OF RESPIRATION
Neural Regulation
 CNS: Controls the rate, depth, and rhythm of breathing.
 Cerebral Cortex: Allows voluntary control of respiration (e.g., holding breath).
Chemical Regulation
 Regulates respiration based on:
o CO₂, O₂, and pH levels in the blood.
 Chemoreceptors detect these changes and signal the nervous system to adjust breathing.

CARDIOVASCULAR PHYSIOLOGY
Cardiopulmonary Circulation
 Deoxygenated blood flows to the right side of the heart and then to the lungs for oxygenation.
 Oxygenated blood returns to the left side of the heart and is pumped to the body tissues.
Structure and Function
 The right ventricle pumps deoxygenated blood to the lungs.
 The circulatory system allows for gas exchange, nutrient delivery, and waste removal at the tissue level.

Myocardial Pump
 The heart consists of two atria and two ventricles.
 Starling’s Law: The more the heart muscle stretches, the stronger the contraction.

Myocardial Blood Flow

 Blood flows one way through four heart valves:
o S1: Closure of mitral and tricuspid valves.
o S2: Closure of aortic and pulmonic valves.

CORONARY ARTERY CIRCULATION

 Coronary arteries supply oxygen and nutrients to the myocardium and remove waste products.

Systemic Circulation
 Arteries and veins transport oxygen, nutrients, and remove waste throughout the body.

BLOOD FLOW REGULATION

 Cardiac Output (CO): The volume of blood pumped by the left ventricle per minute.
o Formula: CO = Stroke Volume × Heart Rate
 Stroke Volume: Amount of blood ejected per heartbeat.
 Preload: The pressure from the volume of blood in the ventricles at the end of diastole.
 Afterload: The resistance the left ventricle must overcome to eject blood.

CONDUCTION SYSTEM
 Transmits electrical impulses that regulate the heartbeat.
 Normal Sinus Rhythm (NSR): Begins at the SA node and follows the normal conduction pathway.
o P wave: Atrial depolarization
o PR interval: Delay at the AV node
o QRS complex: Ventricular depolarization
o QT interval: Duration of ventricular activity
o
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 FACTORS AFFECTING OXYGENATION
PHYSIOLOGICAL FACTORS
 Decreased oxygen-carrying capacity (e.g., anemia)
 Hypovolemia (low blood volume)
 Decreased inspired oxygen concentration (e.g., high altitude)
 Increased metabolic rate (e.g., fever, exercise)
CONDITIONS AFFECTING CHEST WALL MOVEMENT
 Pregnancy
 Obesity
 Neuromuscular diseases
 Musculoskeletal abnormalities
 Trauma
 CNS disorders
Chronic Diseases
 Conditions such as COPD, heart failure, or anemia that impair oxygenation and respiratory function.

ALTERATIONS IN RESPIRATORY FUNCTIONING

Hypoventilation
 Inadequate alveolar ventilation.
 Body does not get enough oxygen or fails to eliminate enough CO₂.
Hyperventilation
 Breathing faster or deeper than needed.
 Results in excess elimination of CO₂ beyond metabolic requirements.
Hypoxia
 Low oxygen levels in tissues at the cellular level.
 Can result from hypoventilation, anemia, or poor circulation.
Cyanosis
 Bluish discoloration of the skin and mucous membranes.
 Indicates severe hypoxia or poor oxygenation.

ALTERATIONS IN CARDIAC FUNCTIONING

DISTURBANCES IN CONDUCTION
 Abnormal electrical impulses that do not originate from the SA node.
 Examples:
o Dysrhythmias
o Atrial fibrillation
o Paroxysmal supraventricular tachycardia
o Ventricular dysrhythmias
ALTERED CARDIAC OUTPUT
 Heart’s ability to pump blood effectively is impaired.
 Types:
o Left-sided heart failure: Blood backs up in the lungs (pulmonary symptoms).
o Right-sided heart failure: Blood backs up in the body (peripheral edema).
IMPAIRED VALVULAR FUNCTION
 Valves do not open or close properly.
 Affects unidirectional blood flow and increases cardiac workload.
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 
MYOCARDIAL ISCHEMIA
 Decreased blood flow to the heart muscle.
 Conditions:
o Angina: Chest pain due to temporary ischemia.
o Myocardial infarction (MI): Heart attack due to prolonged ischemia causing tissue damage.
ASSESSMENT
NURSING HISTORY
Focus on identifying respiratory or cardiovascular issues:
 Symptoms: Pain, fatigue, dyspnea (difficulty breathing), cough, wheezing
 Lifestyle factors: Smoking, allergies, exposure to infections
 Medical history: Respiratory infections, medications, chronic diseases
 Health risks: Environmental or occupational exposures
Physical Examination
 Inspection: Observe skin/mucous membrane color, LOC (level of consciousness), breathing pattern, chest movement,
appearance, and circulation.
 Palpation: Assess the chest, feet, legs, and peripheral pulses.
 Percussion: Detect abnormal fluid, air, or diaphragmatic movement.
 Auscultation: Listen for normal/abnormal heart and lung sounds.
Diagnostic Tests
 Blood tests
 Chest X-rays
 Tuberculosis (TB) skin test

NURSING DIAGNOSES
Common nursing problems related to respiratory and cardiac issues:
 Activity intolerance
 Decreased cardiac output
 Fatigue
 Impaired gas exchange
 Impaired verbal communication
 Ineffective airway clearance
 Risk for aspiration
 Ineffective breathing pattern
 Ineffective health maintenance

IMPLEMENTATION

HEALTH PROMOTION
 Vaccinations: Flu and pneumococcal vaccines
 Healthy lifestyle: Avoiding risk factors, balanced diet, regular exercise
 Reduce exposure: Avoid secondhand smoke, pollutants, and harmful chemicals
ACUTE CARE INTERVENTIONS
 Dyspnea management: Provide comfort and support breathing
 Airway maintenance
 Mobilizing secretions:
o Hydration
o Humidification
o Nebulization
o Coughing and deep breathing
o Chest percussion

SUCTIONING TECHNIQUES
1. Oropharyngeal and Nasopharyngeal Suctioning
 For patients who can cough but can't clear secretions.
2. Orotracheal and Nasotracheal Suctioning
 For patients unable to cough up secretions and do not have an artificial airway.
3. Tracheal Suctioning
 Used in patients with an artificial airway (e.g., tracheostomy).

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 TRACHEAL CARE
SUCTIONING METHODS
 Open suctioning: Involves removing the suction catheter and reusing
it for each suctioning attempt.
 Closed suctioning: The catheter remains in place, reducing risk of infection
and maintaining sterile conditions.

ARTIFICIAL AIRWAYS
Oral Airway
 Prevents tracheal obstruction by preventing the tongue from blocking the airway.
Endotracheal and Tracheal Airways
 Short-term use: To ventilate, relieve upper airway obstruction, protect from aspiration, or
clear secretions.
Tracheostomy
 Long-term airway assistance: A surgical incision is made into the trachea for long-term
ventilation or airway support.

MAINTENANCE AND PROMOTION OF LUNG EXPANSION

Ambulation
 Walking encourages deep breathing and lung expansion.
Positioning
 Proper positioning reduces pulmonary stasis, maintains good ventilation, and
ensures oxygenation.
Incentive Spirometry
 Encourages deep breathing to increase lung volume and improve oxygenation.
Invasive Mechanical Ventilation
 Life-saving technique used when artificial airways are in place (e.g., endotracheal tube or tracheostomy).
 Indications: Severe respiratory failure or compromised airway.
Noninvasive Ventilation
 Maintains positive airway pressure and improves ventilation without intubation.
o CPAP: Continuous Positive Airway Pressure.
o BiPAP: Bilevel Positive Airway Pressure.
Chest Tube
 Used for conditions like pneumothorax (air in chest cavity) and hemothorax (blood in chest cavity).
 Special considerations: Careful monitoring and proper positioning.

MAINTENANCE AND PROMOTION OF OXYGENATION

Oxygen Therapy
 Indications: To relieve or prevent hypoxia.
Safety Precautions
 Always adhere to safety guidelines when administering oxygen.
Oxygen Supply
 Portable tanks or wall-piped system.
Methods of Oxygen Delivery
 Nasal cannula: Delivers low-flow oxygen.
 Oxygen mask: Higher flow, used for more concentrated oxygen.
Oxygen Masks
 Simple Face Mask: Short-term oxygen delivery.
 Plastic Face Mask with Reservoir Bag: Provides higher concentrations of oxygen.
 Venturi Mask: Delivers precise concentrations of oxygen.

HOME OXYGEN THERAPY

Indications
 PaO₂ ≤ 55 mm Hg or SaO₂ ≤ 88% at rest, during exertion, or with exercise.
Administered via:
 Nasal cannula or face mask.
 T-tube or tracheostomy collar if the patient has a permanent tracheostomy.
Benefits

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  Helps chronic cardiopulmonary disease patients improve oxygenation and quality of life.

RESTORATION OF CARDIOPULMONARY FUNCTIONING

Cardiopulmonary Resuscitation (CPR)
 Steps:
1. Circulation: Ensure blood flow through chest compressions.
2. Airway: Open the airway to facilitate breathing.
3. Breathing: Provide rescue breaths.
4. Defibrillation: Use an automated external defibrillator (AED) if needed to restore normal heart rhythm.

RESTORATIVE AND CONTINUING CARE

Cardiopulmonary Rehabilitation
 Components:
o Controlled physical exercise
o Nutrition counseling
o Relaxation and stress management
o Medications
o Oxygen therapy
o Systemic hydration and compliance to improve overall cardiopulmonary health.
Respiratory Muscle Training
 Strengthening respiratory muscles to improve lung function.
Breathing Exercises
 Pursed-lip breathing: Slows the breathing rate and improves oxygen exchange.
 Diaphragmatic breathing: Enhances lung ventilation and oxygenation by engaging the diaphragm.

FLUID, ELECTROLYTE, AND ACID-BASE BALANCE

Overview
 Body fluids: Surround and are inside cells. They contain electrolytes (e.g., sodium, potassium) and have a certain level of
acidity (pH).
 Fluid, electrolyte, and acid-base balance are crucial for the health and function of body systems, influencing cell function
and systemic stability.
Characteristics of Body Fluids:
 Volume: The amount of fluid in the body.
 Osmolality: The concentration of solutes in the fluid.
 Composition: The types of electrolytes in the fluid (e.g., sodium, potassium).
 pH: The degree of acidity or alkalinity of body fluids.
Regulatory Mechanisms
 The body uses mechanisms to maintain balance:
o Antidiuretic hormone (ADH): Regulates fluid retention by kidneys.
o Renin-angiotensin-aldosterone system: Regulates blood pressure and fluid balance.
o Atrial natriuretic peptide (ANP): Helps to reduce blood volume and pressure.
Fluid Balance
 Fluid Intake: The amount of fluid taken in (oral, IV, etc.).
 Fluid Distribution: The movement of fluid between compartments (e.g., blood vessels, cells).
 Fluid Output: The loss of fluid through kidneys, lungs, skin, etc.
Fluid Balance
COMPONENTS OF FLUID BALANCE
1. Fluid Intake:
o Regulated by thirst, which is triggered when plasma osmolality increases.
o Average intake: ~2300 mL/day.
2. Fluid Distribution:
o Extracellular (outside cells) and intracellular (inside cells) fluid compartments.
o Vascular (in blood vessels) and interstitial (between cells) spaces.
3. Fluid Output:
o Fluids are lost through kidneys, skin, lungs, and the GI tract.
o Insensible loss: Not measurable (e.g., evaporation from skin).
o Sensible loss: Measurable loss (e.g., urine, sweat).
Hormonal Influences on Fluid Balance
 Antidiuretic hormone (ADH): Regulates water retention in kidneys.
 Renin-angiotensin-aldosterone system (RAAS): Controls fluid balance and blood pressure.
 Atrial natriuretic peptide (ANP): Reduces blood volume and pressure.

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 FLUID IMBALANCES
Extracellular Fluid (ECF) Imbalances
1. Volume Imbalance: Refers to a deficit or excess in extracellular fluid.
2. Osmolality Imbalance: Refers to abnormalities in the concentration of solutes in the fluid.
o Hypernatremia ("water deficit"): High sodium concentration.
o Hyponatremia ("water excess"): Low sodium concentration.
Clinical Dehydration
 Combination of ECV deficit (extracellular fluid volume deficit) and hypernatremia (high sodium).

ELECTROLYTE BALANCE
Electrolyte Intake and Absorption
 Electrolytes like potassium (K+), calcium (Ca²+), magnesium (Mg²+), and phosphate (Pi) are primarily absorbed from food
and fluids.
Electrolyte Distribution
 Plasma concentrations of these electrolytes are very low compared to their concentrations inside cells and bones, which is
necessary for normal muscle and nerve function.
Electrolyte Output
 Electrolytes are lost through urine, feces, sweat, vomiting, and drainage (e.g., through fistulas).

ELECTROLYTE IMBALANCES
1. Potassium (K+) Imbalances:
o Hypokalemia: Low potassium levels.
o Hyperkalemia: High potassium levels.
2. Calcium (Ca²+) Imbalances:
o Hypocalcemia: Low calcium levels.
o Hypercalcemia: High calcium levels.
3. Magnesium (Mg²+) Imbalances:
o Hypomagnesemia: Low magnesium levels.
o Hypermagnesemia: High magnesium levels.
ACID-BASE BALANCE
Key Concepts
 Acid-Base Regulation: The body regulates acid-base balance through acid production, buffering, and excretion
mechanisms.
 Acid and Base: Acids release hydrogen ions (H+), and bases take up H+ ions.
 pH Scale:
o Range: 1.0 (very acid) to 14.0 (very base).
o Neutral pH: 7.0.
o Normal arterial blood pH: 7.35 to 7.45.
 Importance: Maintaining pH within this range is crucial for optimal cell function.
Acid Production
 Carbonic Acid Formation:
o Formula: CO2 + H2O ↔ H2CO3 ↔ H+ + HCO3-
o Carbon dioxide and water combine to form carbonic acid, which dissociates into hydrogen ions and bicarbonate.
Acid Buffering
 Buffers: Pairs of chemicals that help maintain a stable pH.
o Example: HCO3- + H+ ↔ H2CO3 (bicarbonate + hydrogen ions ↔ carbonic acid).
o This system prevents pH fluctuations by neutralizing excess acids or bases.
Excretion Systems
 Lungs: Excrete carbonic acid (CO2 and water are expelled when breathing out).
 Kidneys: Excrete metabolic acids (all acids except carbonic acid).

ACID-BASE IMBALANCES
Acidosis Types
1. Respiratory Acidosis:
o Caused by alveolar hypoventilation (insufficient ventilation).
o Lungs can't excrete enough CO2, leading to excess carbonic acid and decreased pH.
2. Metabolic Acidosis:
o Caused by an increase in metabolic acids or a decrease in bicarbonate.
o The kidneys can't excrete enough metabolic acids, leading to increased acid levels and decreased pH.
o Results in decreased level of consciousness.

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Alkalosis Types
1. Respiratory Alkalosis:
o Caused by alveolar hyperventilation (excessive breathing).
o Lungs excrete too much CO2, leading to a deficit of carbonic acid and increased pH.
2. Metabolic Alkalosis:
o Caused by a direct increase in bicarbonate or a decrease in metabolic acid.
o Leads to increased blood bicarbonate and higher pH.

Physical Assessment of Fluid and Acid-Base Balance

1. Daily Weights:
o Used to assess fluid status (should be measured under consistent conditions).
2. Fluid Intake and Output (I&O):
o Track the 24-hour fluid intake (all liquids taken orally or via IV) and output (urine, diarrhea, vomitus, drainage,
etc.).
3. Laboratory Studies: Used for diagnostic purposes, including pH, electrolytes, and gas exchange.

NURSING DIAGNOSIS
 Decreased cardiac output
 Acute confusion
 Impaired gas exchange
 Excess fluid volume
 Risk for electrolyte imbalance
 Deficient knowledge regarding disease management
 Risk for injury
 Deficient fluid volume

IMPLEMENTATION
Health Promotion
 Educate patients about fluid replacement and the risks of fluid and electrolyte imbalances.
Acute Care
 Enteral and parenteral fluid replacement:
o Use of crystalloids (electrolyte-containing fluids).
o Colloids (e.g., blood components).
o Total Parenteral Nutrition (TPN) for specific nutritional needs.

INTRAVENOUS (IV) THERAPY

IV Therapy: Crystalloids
 Crystalloid solutions are commonly used in IV therapy.
Types of Solutions
1. Isotonic:
o Solution with the same osmolarity as the blood plasma
(e.g., Normal Saline 0.9% NaCl).
o Used to maintain fluid balance without changing the cell
volume.
2. Hypotonic:
o Solution with lower osmolarity than the blood plasma (e.g.,
0.45% NaCl).
o Helps rehydrate cells by moving water into them.
3. Hypertonic:
o Solution with higher osmolarity than the blood plasma (e.g., 3% NaCl).
o Draws water out of cells, used for specific conditions like cerebral edema.
Caution
 Rapid or excessive infusion of any IV fluid can cause serious complications like fluid overload or electrolyte imbalances.

VASCULAR ACCESS DEVICES (VADS)

Equipment for IV Therapy
 Vascular Access Devices (VADs): Essential tools used to access the blood vessels for IV infusion.
 Other Equipment:

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 o Tourniquets, clean gloves, dressings, IV fluid containers, tubing, and electronic infusion devices (EIDs) (also called
infusion pumps).

Initiating IV Therapy

Steps for Initiating an IV Line

1. Maintaining the System:
o Ensure the IV system remains sterile and intact.
2. Changing IV Fluid Containers and Tubing:
o Periodically change fluid containers, tubing, and dressings.
3. Assisting with Self-Care:
o Help patients with activities of daily living if they need assistance with their IV
setup.
Complications of IV Therapy
 Common issues include:
o Fluid overload
o Infiltration: Fluid leakage into surrounding tissue.
o Extravasation: Leakage of caustic drugs into tissues.
o Phlebitis: Inflammation of the vein.
o Local infection
o Bleeding at the infusion site

BLOOD TRANSFUSION

Blood Component Therapy

 IV administration of whole blood or blood components (e.g., red blood
cells, platelets, plasma).
Blood Types and Groups
 Blood transfusion requires careful matching of blood groups and types to
prevent adverse reactions.
Autologous Transfusion
 Autologous transfusion refers to the patient donating their own blood for
future use.
Transfusion Reactions and Adverse Effects
 Monitor for reactions such as fever, chills, or difficulty breathing.

Interventions for Electrolyte and Acid-Base Imbalances

1. Electrolyte Imbalances:
o Support prescribed therapies: Administer medications or treatments as ordered.
o Correct acid-base imbalance: Help restore the balance by following medical protocols.
o Ensure patient safety: Monitor for signs of electrolyte disturbances or complications.
2. Acid-Base Imbalances:
o Arterial Blood Gases (ABGs): Help assess the patient's acid-base status and guide treatment.

RESTORATIVE CARE
Home IV Therapy
 Some patients may require continued IV therapy at home for chronic conditions or long-term treatment.
Nutrition Support
 Offer nutrition support, particularly in patients with conditions affecting their ability to eat or absorb nutrients.
Medication Safety
 Ensure that
medications
(including OTC drugs
and herbal
preparations
) are safe and
appropriate
for the patient's
condition.

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