Chapter 9 Ventilation Assistance Flashcards
Essential nursing interventions (3)
- Maintain adequate airway
- Ensure adequate ventilation
- Ensure adequate oxygenation
Respiratory A & P
- Function is?
- Lungs
- Upper airway
- Lower airway
- Function is gas exchange
- Lungs
- Left: two lobes
- Right: three lobes
- Upper airway
- Nasal cavity
- Pharynx
- Lower airway
- Larynx
- Trachea
- Right and left mainstem bronchi, bronchioles, and alveoli
Physiology of Breathing
- Rest
- Inspiration
- Expiration
- Rest:
- Intrapleural pressure < atmospheric
- Intraalveolar = atmospheric
- Inspiration:
- Intrapleural pressure more negative
- Intraalveolar negative = airflow
- Expiration:
- Passive when intrapulmonary
pressure exceeds atmospheric
- Passive when intrapulmonary
Gas Exchange
- Ventilation =
- Diffusion of O2 and CO2 at?
- Oxygenated blood is?
- Diffusion of O2 and CO2 occurs at?
- Ventilation = movement of O2 and CO2 in and out of alveoli
- Diffusion of O2 and CO2 at pulmonary capillary
- Oxygenated blood perfused or transported to the tissues
- Diffusion of O2 and CO2 occurs at cellular level
* Transport of CO2 to the right side of the heart
* Diffusion based on concentration gradients
Regulation of Breathing
- Respiration is stimulated by?
- COPD patients?
- Respiration stimulated by elevated CO2
- Not true for COPD
- Stimulus is hypoxia
- Rationale for low oxygen in patients with COPD
- Work of Breathing (WOB)
- Amount of effort required to maintain ventilation
- Respiratory pattern changes automatically
- WOB increases, more energy needed
- WOB high, leads to muscle fatigue and eventually respiratory failure
Compliance
- What is it?
- Types
- Distensibility or stretch
- Determined by elasticity, “recoil”
- Elastic recoil and compliance are inversely related
- Types
- Static—measured under condition of no airflow (inspiratory hold)
- Dynamic—measured while gases flowing
Resistance
- Opposition to gas flow in the airways
- Airway length
- Airway diameter
- Small tube
- Spasms
- Mucus
- Flow rate of gases
- Increased breathing effort
Lung Volumes and Capacities (2)
- Assess baseline function
- Monitor responses
Selected Measures
- Tidal Volume (TV)
- Functional Residual Capacity (FRC)
- Vital Capacity (VC)
- Tidal Volume (TV)
- Normal breath; 500 mL or 5 to 7 mL/kg
- Functional Residual Capacity (FRC)
- Volume of gas remaining in the lungs at normal resting expiration
- Average: 2300 mL
- Vital Capacity (VC)
- Maximum volume of gas forcefully expired after maximum inspiration
- Average: 4600 mL
Health History (8)
- Tobacco pack per year history
- Occupational history
- Sputum production
- Shortness of breath, dyspnea, cough, anorexia, weight loss, and chest pain
- Oral and inhalant respiratory medicines
- OTC drugs
- Allergies: medication and environmental
- Last chest x-ray and tuberculosis screen
Physical Examination
- Inspection
- Respiratory rate
- Inspection
- Head, neck, fingers, and chest
- Accessory muscles, sternal retractions, nasal flaring, asymmetrical chest movements, open-mouth breathing, and gasping breaths
- Respiratory rate
- Tachypnea: rate > 20
- Bradypnea: rate < 10
- Assess rate and depth and altered patterns
Abnormal Breathing Patterns (4)
- Cheyne-Stokes: cyclical with apneic periods
- Biot’s: cluster breathing
- Kussmaul’s: deep, regular, and rapid
- Apneustic: gasping inspirations
Cheyne-Stokes
Respirations gradually increase in depth, then become more shallow; followed by a period of apnea
Biot’s
Highly irregular breathing pattern with abrupt pauses between efforts
Kussmaul’s
Respiration faster and deeper without pauses
Apneustic
Respirations prolonged, gasping, followed by extremely short, inefficient expiration
Palpation
-Evaluate (5)
- Chest wall excursion
- Tracheal deviation
- Chest wall tenderness
- Subcutaneous crepitus
- Tactile fremitus
Percussion
- Resonance:
- Dullness:
- Flatness:
- Hyperresonance:
- Tympany:
- Resonance: normal lung sound
- Dullness: denser than normal tissue
- Flatness: air is absent
- Hyperresonance: increased amount of air
- Tympany: air-filled area
Auscultation
- Assess?
- Environment
- Approach
- Assess breath sounds, presence of adventitious lung sounds, voice sounds
- Quiet environment
- Systematic approach
Breath Sounds
- Normal
- Advenitious
- Normal
- Bronchial
- Bronchovesicular
- Vesicular
- Adventitious sounds
- Crackles
- Rhonchi
- Wheezes
- Pleural friction rub
- Stridor
Arterial Blood Gases
- Adequacy of oxygenation and ventilation
- Acid-base status
- Interpret in conjunction with:
- Clinical history
- Physical assessment
Oxygenation
- PaO2─partial pressure of oxygen dissolved in arterial blood
- SaO2─amount of oxygen bound to hemoglobin
- PaO2─partial pressure of oxygen dissolved in arterial blood
- Normal value 80 to 100 mm Hg
- Decreases in elderly
- Value < 60 mm Hg treated
- Value < 40 mm Hg is life threatening
- SaO2─amount of oxygen bound to hemoglobin
- Normal value 92% to 99%
- Frequently measured via pulse oximetry (SpO2)
Hypoxemia:
decreased oxygenation of arterial blood
Hypoxia:
decreased oxygenation at tissue level
PaO2 and SaO2 Relationship
- Oxyhemoglobin dissociation curve
- Critical zone: PaO2 < 60 mm/Hg
- Shifts of oxyhemoglobin dissociation curve
- Acidosis: release of oxygen to tissues
- Alkalosis: hemoglobin holds on to oxygen
pH
- Concentration
- Normal range
- Concentration of hydrogen ions (H+)
- Normal range 7.35 to 7.45
- pH < 7.35 = acidosis
- pH > 7.45 = alkalosis
PaCO2
- What is it?
- Normal value
- Partial pressure of carbon dioxide in arterial blood
- Normal value 35 to 45 mm Hg
- PaCO2 > 45 mm Hg = Acidosis
- PaCO2 < 35 mm Hg = Alkalosis
HCO3— Bicarbonate
- What is it?
- Normal value
- Concentration of sodium bicarbonate in the blood
- Normal value is 22 to 26 mEq/L
- HCO3 < 22 = Acidosis
- HCO3 > 26 = Alkalosis
Buffer System
- Maintain body’s pH
- Substances that change the pH when either acids or bases are added
Bicarbonate Buffer System
- Most common
- Activated as H+ ions increase
- Increased H+ ions combined with HCO3 to form carbonic acid (H2CO3)
- Carbonic acid breaks down into H2O and CO2
Respiratory Buffer System
- Excretes excess CO2 from system when metabolic disorder occurs
- Immediate action
Base Excess or Base Deficit
- Normal range
- Base deficit occurs when?
- Base excess occurs when?
- The normal range for base deficit/base excess is −2 to +2 mEq/L.
- Base deficit occurs when all body’s buffers are used up – Acidosis
- Base excess occurs when the body’s buffers are increased - Alkalosis
Compensation
1)
2)
3)
1) None
2) Partial: mechanisms occurring; pH abnormal
3) Complete: mechanisms occurring; pH normal range
Interpretation of ABGs
STEP 1: Look at each number and label
STEP 2: Evaluate oxygenation
STEP 3: Determine acid-base status. Evaluate the pH
STEP 4: Determine the primary cause of the acid-base status (respiratory or metabolic)
STEP 5: Determine compensation (absent, partial, or complete)
Oxygenation
- Pulse oximetry (SpO2) noninvasive measure
- Value of 90% = PaO2 60 mm Hg
- Ensure accurate readings
- Limit movement
- Avoid edematous areas
- Effect of sunlight, fluorescent light, nail polish, artificial nails, and dyes
- Periodic ABGs to compare value with SaO2
Assessment of Ventilation
- End-tidal Co2 (ETCO2)
- CalorimetricCo2 detector
- End-tidalCO2 (ETCO2)
- Must compare with ABGs and use for trending
- Values tend to be 2 to 5 mm Hg less than PaCO2
- CalorimetricCO2 detector
- Disposable devices