Post on 16-Apr-2018
transcript
12/13/2017
1
Pulmonary Assessment
Reid Blackwelder, MD, FAAFP
Professor and Chair, Family Medicine
Quillen Colege of Medicine, ETSU
Objectives
• Understand anatomy and physiology of
pulmonary assessment techniques
• Remember approaches to CXR
interpretation and ABG
• Recognize common spirometry patterns
• Know when to use provocative testing
Control of Respiration Normal Oxygen Transport from Air to Tissues
Normal Oxygen Transport from Air to Tissues
1. Nose: Filters large particles (> 10um). 2. Vocal cords: Protects from aspiration.
3. Lower airway branching: Filters intermediate particles (2–10um).
4. Alveolar: A. Ciliary function.
B. Macrophage.C. Secretory IgA.
5. Cough: Protective reflex mechanism that removes foreign particles and
mucus from the airway.
Effective cough requires:1. Cough receptors
2. Afferent fibers 3. Cough center in the brain
4. Efferent fibers (phrenic & spinal motor nerves innervate diaphragm &
intercostal muscles).
Normal Respiratory Defense
12/13/2017
2
Intial Assessment
• History
• Physical exam
– Vitals
– Include pulse ox
– Watch (or instruct team) for changes with activity
Subjective
• HPI
– Dyspnea
– Cough
– Wheeze
– Consider pulmonary and cardiac causes
• Past Medical History
– Lung problems
• Social Hx
– Smoking
– Environmental exposures
• Apnea
• Tachypnea
• Stridor
• Cough
• Wheezing
Respiratory Signs and Symptoms
Objective
• VS for tachypnea (>12-16)
• Description of habitus
– Tripod position
– Pectus
– Scoliosis
• Abnormal sounds (never listen through gown)
– Stridor
– Crackles/Rhonchi vs wheezes
– Results of maneuvers
Pulmonary Findings on Exam
Effusion Consolidation COPD Pneumothorax
Trachea Dev Contralateral None None Contralateral
Fremitus Decreased Increased Decreased Decreased
Percussion Dull Dull resonance resonance
Pectoriloquy Decreased Increased Decreased Decreased
Breath Sounds Decreased Decreased Crackles Decreased
Lung Sounds
• Nice link with basic review
• https://www.easyauscultation.com/lung-
sounds
12/13/2017
3
Special Maneuvers
• Vocal fremitus
– Ulnar edge of hand on chest wall
– Patient says “ninety-nine” or “one, two, three”
• Increased vibrations from increased density
• Decreased from fatty tissue, COPD, effusion
• Percussion
– Most students and residents do not do this well!
– Dullness from consolidation, effusion
Special Maneuvers
• Pectoriloquy/Egophony
• Spoken words are attenuated as they move
through airspace
• If consolidation present, attenuation is reduced
– Increased transmission is pectoriloquy
• Ninety-nine again
– The change in pitch is called egophony
• Patient says “eee” heard as “aay”
• Remember pneumonia is a clinical not
radiologic dx!
CXR Method
• Airway
• Bones
• Cardiac
• Diaphragm
• Effusions
• Free Air
• Gadgets
• Hilum
• Interstitium
Cardiomegaly
Effusions Effusions
12/13/2017
4
Infiltrate Where is the Infiltrate?
Infiltrate Infiltrate Patterns and Pathogens
• CXR Pattern Possible Pathogens
• Lobar S.Pneumo, Kleb, H flu, Gram Neg
• Patchy Atypicals, Viral, Legionella
• Interstitial Viral, PCP, Legionella
• Cavitary Anaerobes, Kleb, TB,
S.Aureus,fungi
• Large effusion Staph, Anaerobes, Kleb
Brief Acid-Base Review
• pH 7.47 PCO2 20 HCO3 19
– Dx?
– Respiratory alkalosis
• pH 7.25 PCO2 60 HCO3 27
– Dx?
– Respiratory acidosis
• pH 7.10 PCO2 10 HCO3 6
– Dx?
– Metabolic acidosis
pH Determines
• Acidemia (<7.35-7.40)
• Alkalemia (>7.45)
12/13/2017
5
Acidemia
• If the primary process is Metabolic
– The HCO3 must be < 24
– Metabolic Acidosis
• If the primary process is Respiratory
– The pCO2 must be > 45
– Respiratory Acidosis
Alkalemia
• If the primary process is Metabolic
– The HCO3 must be > 27
– Metabolic Alkalosis
• If the primary process is Respiratory
– The pCO2 must be << 40
– Respiratory Alkalosis
Evaluate Compensation!
Metabolic Acidosis
✶Decrease in pCO2 = 1.3 (decrease in
HCO3)
✶pCO2 will not go < 10
✶Max compensation takes 12-24 hrs
A Patient with DKA
✶HCO3 8, and pCO2 20
✶Decrease in pCO2 = 1.3 (24 – 8)
= 20.8
✶pCO2 = 40 – 20.8
= 19
✶Compensated Metabolic Acidosis
A Patient with DKA
✶HCO3 8, and pCO2 28
✶Decrease in pCO2 = 1.3 (24 – 8)
= 20.8
✶pCO2 = 40 – 20.8
= 19
✶Inadequately compensated Metabolic
Acidosis
✶Possible etiology?
Causes of Respiratory Acidosis
• CNS depression
• Sedative OD
• Acute airway obstruction
• COPD
• Pulmonary edema/infection
• Neuromuscular disorders
• Cardiopulmonary arrest
12/13/2017
6
Causes of Respiratory Alkalosis
• Anxiety (hyperventilation)
• CNS tumor/infection/stroke
• Pulmonary emboli
• Pneumonia
• Drugs
Salicylates, catecholamines, progesterone
• Hypoxia
• Fever
• Sepsis
Lung Volumes
IRV
TV
ERV
• 4 Volumes
– Inspiratory reserve
– Tidal
– Expiratory reserve
– Residual
• 4 Capacities
– Inspiratory
– Functional residual
– Vital
– Total Lung
RV
IC
FRC
VC
TLC
RV
Residual volume (RV)
• Volume of air remaining in the lungs at the
end of maximal expiration.
• Normally accounts for about 25% of TLC
• Increased in airway narrowing with
– Air trapping (Asthma)
– Loss of elastic recoil (emphysema).
• Decreased with
– Increased elastic recoil (pulmonary fibrosis)
Pulmonary Function
Office Spirometry…
• Do it!
• Critical for diagnosis
and management
• Convenient
• A procedure so you
can charge for it
Forced Expiratory Volume (FEV)
12/13/2017
7
FEV1Volume of air which can be forcibly exhaled
from the lungs in the first second of a forced
expiratory maneuver.
Flow-Volume Loop: Air Flow vs. Volume
Graphic representation ofthe inspiratory andexpiratorymaneuvers
Effort
Dependentflow-limiting
segment at upper
airways
Effort
Independentflow limiting
segment at
lower airways
FEF 25%
Peak Flow
• Obstruction
Flow-Volume Loop
• Restriction
Flow-Volume Loops
Flow-Volume Loops Patterns of ImpairmentObstructive Restrictive
Normal/Big lungs Small lungs
Low Flow Normal Flow
FVC Nl or
FEV1
FEV1/FVC
TLC Nl or
RV
For low FVC, measure lung volumes
12/13/2017
8
Spirometry
NormalLow FEV1/FVC Low FVC
Obstructive Suspect asthma Restrictive
Bronchodilator Trial
FEV1
Asthma
No Change
COPD
DLCO
Nl: Bronchitis Emphysema
DLCO
Methacholine Challenge
FEV1
Asthma
FEV1 Nl
Normal
Bronchoprovocation Testing
• PFTS are tools in the diagnosis of asthma
– Measurement of peak expiratory flow rate
– Spirometry
• May be normal between symptomatic
episodes
• Asthma has characteristic variable airflow
limitation
– Symptoms may only occur with certain
exposures, activity
Bronchoprovocation Testing
• Assesses Bronchial HyperResponsiveness
to external triggers (BHR)
• Excessive response to an aerosolized
provocation that triggers little or no
response in a normal person
• Distinguishes most patients with asthma
– Useful if dx of asthma in question
– Establish dx of occupational asthma
Methacholine challenge testing
• Cholinergic agonist, induces bronchoconstriction
• Patient inhales one or more increasing
concentrations of Methacholine
• Spirometry before and after
• Test stopped if FEV1 decreases > 20% of
baseline
• Negative if does not decrease by 20% with max
dose: makes dx asthma very unlikely
Exercise testing
• Inhale dry, cool air during exercise
– Ambient room temp 68-77 F
– 50% relative humidity
• Treadmill or bicycle
– Exercise at target HR for at least 4 minutes
• Spirometry before and after over periods of time
• Abnormal is fall in FEV1 by 10%
– More than 15% suggests exercise induced
bronchospasm