Download Oxygenation

Chapter 40: Oxygenation
Bonnie M. Wivell, MS, RN, CNS
Structure and Function of the Heart
• Right ventricle pumps
blood through the
pulmonary circulation
• Left ventricle pumps
blood through the
systemic circulation
• The circulatory system
exchanges respiratory
gases, nutrients, and
waste products between
the blood and tissues
Myocardial Pump
• Four chambers: 2 atria, 2 ventricles
• Fill with blood during diastole, empty during systole
• CAD and cardiomyopathy result in decreased pumping
action and decreased stroke volume
• Frank-Starling’s law: the more stretch on the ventricle
muscle, the greater the contraction and the greater the
stroke volume
▫ Diseased heart = contractile response resulting in insufficient
stroke volume → “back up” in pulmonary → Left heart failure
▫ “back up” in circulation → Right heart failure
Myocardial Blood Flow
• Blood flow is unidirectional
• Diastole = AV valves (mitral and tricuspid) open
and blood flows from higher pressure atria to
relaxed ventricles
• Represents S1 or the first heart sound
• Systole = Semilunar (aortic and pulmonic)
valves open, and blood flows from the ventricles
into the aorta and pulmonary artery
• Closer of semilunar valves represents S2
• Murmur caused by regurge from diseased valve
Coronary Artery Circulation
• Supplies the myocardium with oxygen and nutrients and
removes waste
• Left and right coronary arteries rise from the aorta just
above and behind the aortic valve through the coronary
openings
• The left coronary artery, the most abundant blood
supply, feed the left ventricle, which does most of the
heart’s work
• Cardiac Function
• http://www.youtube.com/watch?v=D3ZDJgFDdk0&feat
ure=related
Blood Flow Regulation
• Cardiac Output (CO) = amount of blood ejected
form the left ventricle each minute
• CO changes according to the oxygen and
metabolic needs of the body
• CO = SV x HR
• Stroke Volume (SV) = amount of blood ejected
from the left ventricle with each contraction
• Preload = amount of blood in the LV at the end
of diastole
• Afterload = the resistance to LV ejection
Conduction System
• Heart’s conduction
system generates
impulses needed to pump
blood
• Trace the impulse
• http://www.youtube.com
/watch?v=nK0_28q6Wo
M&NR=1
Normal Sinus Rhythm
Respiratory System
• Lungs transfer O2 from
atmosphere to aveoli
• Ventilation
• Perfusion
• Diffusion
• Respirations
• http://www.youtube.com
/watch?v=hpgCvW8PRY&feature=rela
ted
Work of Breathing
• Intrapleural pressure is negative or different than the atmosphere
▫ Punctured lung – lung collapses
• Inspiration – active process stimulated by chemical receptors in
aorta (O2, CO2)
• Expiration – passive process that depends on elastic recoil
• Surfactant – a chemical produced in the lungs to maintain the
surface tension of the alveoli and keep them from collapsing
• Decreased surfactant from disease can develop atelectasis
• Difficulty breathing – use accessory muscles (elevation of the
clavicles)
• Seen in COPD, causes fatigue
• Compliance – ability of the lungs to distend or to expand in
response to increased intraalveolar pressure; decreased compliance
increases airway resistance
Lung Volumes
Pulmonary Circulation
Respiratory Gas Exchange
• Diffusion – thickness of membrane affects the
rate of diffusion
• Pulm edema, pulm infiltrates, pulm effusion
• Ventilation – amount of O2 entering the lungs
• Perfusion – blood flow to lungs and tissues
• What influences capacity of blood to carry
oxygen?
• Venous blood transports the majority of CO2
Regulation of Respiration
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Neural regulators
Cerebral Cortex
Medulla Oblongata
Chemical regulation
Chemoreceptor
Factors Affecting Oxygenation
• Decrease in Hgb (O2 carrying capacity)
▫ Anemia – s/s fatigue, decreased activity
tolerance, SOB, pallor, tachycardia
• Decreased inspired O2 concentration
• Hypovolemia
• Increase metabolic rate increases O2 demand
▫ Normal in pregnancy, wound healing, and
exercise as the body is building tissue
▫ Fever
Conditions Affecting Chest Wall
Movement
• Pregnancy – baby pushes up against diaphragm
resulting in dyspnea
• Obesity
• MSK abnormalities – pectus excavatum, kyphosis,
lordosis, or scoliosis
• Trauma – multiple rib fractures develop into a flail chest
(unstable chest wall); incisions
• Neuromuscular diseases – Myasthenia gravis, Guillain
Barre syndrome, poliomyelitis
• CNS – brain or spinal cord injury, phrenic nerve damage
→ diaphragm does not descend properl → reduces
inspiration
• Influence of chronic disease (COPD) influences the body
to produce more RBCs (polycythemia vera)
Disturbances in Cardiac Functioning
• Disturbances in conduction – Dysrhythmias
• Altered CO
▫ Left-sided heart failure: decreased CO, pulmonary
congestion
▫ Right-sided heart failure: result of pulm disease or long
term left-sided failure; increase pulm vascular resistance;
congestion in systemic circulation (edema)
• Impaired valvular function – stenosis
• Myocardial ischemia
▫ Angina
▫ MI – females and elderly present differently
Alterations in Respiratory Function
• Goal: PaCO2 between 35-45 mm Hg and PaO2 95-100
mm Hg
• Hyperventilation: state of ventilation in excess of that
required to eliminate the CO2 produced by cellular
metabolism; sometimes chemically induced (salicylate
poisoning, amphetamines)
• Hypoventilation: alveolar ventilation is inadequate to
meet the body’s O2 demand or to eliminate sufficient
CO2; atelectasis
• Hypoxia: inadequate tissue oxygenation at the cellular
level; cyanosis (central vs peripheral)
COPD vs Asthma
• Physiology, emphysema
• http://www.youtube.com/watch?v=aktIMBQSXMo
• http://www.youtube.com/watch?v=82gn_rDRpHk
Developmental Factors
• Infants and toddlers: at risk for URIs which are usually
not dangerous
• School-age children and adolescents: second hand
smoke exposure, may start smoking
• Young and middle-age adults: multiple risk factors such
as unhealthy diet, lack of exercise, stress, OTC and RX
meds not used as intended, illegal substances, and
smoking
• Older adults: calcification of heart valves, SA node and
costal cartilages; osteoporosis changes size and shape of
thorax
Lifestyle
• Modify risk factors
▫ Weight reduction
▫ Smoking cessation
▫ Low-cholesterol, low-Na+
diet
▫ Management of HTN
▫ Moderate exercise
• Substance abuse
• Stress
• Environmental factors
Nutrition
• Cardio-protective nutrition
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Fiber
Whole grains
Fresh fruit
Vegetables
Nuts
Antioxidants
Lean meats, fish, chicken
Omega-3 fatty acids
Assessment
• Nursing History
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Pain
Fatigue
Smoking
Dyspnea/Orthopnea
Cough/hemoptysis
Wheezing
Environmental or
geographical exposures
Respiratory infections
Allergies
Health risks
Medications
Physical Exam
• Inspection – symmetry, breathing patterns,
chest movement, barrel shape in COPD
• Pink puffers/Blue bloaters
• Palpation
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Thoracic excursion
Tenderness
Tactile fremitus, thrills, heaves, PMI
CMS, edema
• Percussion
• Auscultation
Diagnostic Tests
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CBC
Cardiac Enzymes
Myoglobin
Serum Electrolytes
Cholesterol
Sputum (AFB, C/S,
Cytology)
• ECG
• Stress test (Exercise
vs Thallium)
• Cardiac cath
• PFTs
• Bronchoscopy
• Lung Scan
• Thoracentesis
Nursing Diagnosis
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Activity intolerance
Anxiety
Decreased cardiac input
Fatigue
Impaired gas exchange
Ineffective airway
clearance
• Risk for infection
• Impaired spontaneous
ventilation
• Impaired verbal
communication
• Ineffective breathing
pattern
• Ineffective health
maintenance
• Risk for imbalanced fluid
volume
Planning
• Goals and outcomes
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Pt. will have clear lungs to auscultation
Pt. will achieve bilateral lung expansion
Pt. will have a productive cough
Pt. will have maintain/improve pulse ox
• Setting priorities
• Collaborative care
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Family members
Colleagues
Other specialists
Pulmonary rehab
Implementation
• Health Promotion
▫ Vaccinations
• Healthy Lifestyle Behavior
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Low-fat, high-fiber diet
Reduce stress
Exercise
Maintain a good BMI
Monitor cholesterol, triglycerides, HDL, LDL
Eliminate smoking
Avoid pollutants/second hand smoke
Adequate hydration and sodium intake (especially if on
diuretics
Acute Care
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Dyspnea management
Airway maintenance
Mobilization of pulmonary secretions
Hudification
Nebulization
Chest physiotherapy (CPT)
▫ Postural drainage (see pages 932-933)
• Suctioning
▫ Oropharyngeal, nasopharyngeal, orothracheal,
nasotracheal
Acute Care Continued
• Artificial airways (for decreased LOC)
• Oral airway (displaces tongue)
• Endotracheal and tracheal airway (high risk for
infection)
• Maintenance and promotion of lung expansion
▫ Positioning (turn, cough, deep breath)
▫ Incentive Spirometry (IS)
Procedures
• Thoracentesis
▫ http://www.youtube.com/watch?v=6-9WY2dbpc&feature=related
• Chest tube insertion
▫ http://www.youtube.com/watch?v=B0wGmWn8
Ubs&feature=related
• Pleur-Evac
▫ http://www.youtube.com/watch?v=-I4bj0qwhM0
Chest Tubes
• Pneumothorax – a collection of air in the pleural space;
loss of negative pressure in the intrapleural space
• Spontaneous, or trauma
• Often caused by the rupture of an air-filled sac in the lung,
called a bleb or bulla
• From procedure such as insertion of central line
• Hemothorax – accumulation of blood and fluid in the
pleural cavity usually as a result of trauma
• Tension pneumo – air pressure builds in the pleural
space, collapsing the lung and creating a life-threatening
event
Oxygen Therapy
• Goal
• Purpose
• Safety
Methods of Delivery
• Nasal cannula
• Simple face mask
• Venturi mask
• Home O2
▫ Compressed
▫ Liquid
▫ Concentrator
Restorative and Continuing Care
• Hydration
• Coughing techniques
• Respiratory muscle training
• Breathing exercises
▫ Pursed-lip breathing to blow off CO2
• Diaphragmatic breathing
Evaluation