pulmonary function, kidneys and urinalysis, liver and pancreas, endocrine, heart, lipid

what are pulmonary function tests (PFTs)

assessments of lung function that are composed of many different components

spirometry is performed to reveal the presence of

obstructive disease

lung volumes determine the presence of

restrictive disease

diffusion capacity tests ascertain the

adequacy of gas exchange

true or false: significant bronchodilator response on spirometry testing can differentiate between COPD and asthma

false (response is common in both)

postbronchodilator spirometry is necessary to determine

the presence of persistent airflow obstruction and the degree of disease severity

restrictive lung diseases are a decrease in

lung volume; defined by a decrease in TLC

ventilation

movement of air in and out of the lungs

perfusion

movement of blood through the lungs

diffusion

gas exchange that occurs in alveoli across a thin membrane separating capillary blood from exchanged air

bronchi are responsible for

delivering inspired air to the lungs

lungs are in the

pleural cavity in the thorax

the right lung has ___ lobes, the left lung has ____ lobes

3, 2

why are PFTs clinically useful

-diagnosis of respiratory diseases

-classification of diseases

-therapeutic decision making

-monitoring disease progression

obstructive lung diseases

reversible or persistent blockage in airways; decreased flow rate of air but little impact on total volume per breath

examples of obstructive lung diseases

asthma, COPD, cystic fibrosis

restrictive lung diseases

lungs limited in amount of air they contain; decreased total volume of air but little impact on flow rate of air

examples of restrictive lung diseases

kyphosis, sarcoidosis, idiopathic pulmonary fibrosis, myasthenia gravis

what does spirometry measure

air movement in and out of lungs during forced maneuvers (FVC, FEV1)

when is spirometry used

diagnosis of asthma and COPD

what is FVC

forced vital capacity - total volume of air forcefully and rapidly exhaled in one breath

what is FEV1

forced expiratory volume in 1 second - total volume of air a patient is able to exhale in the first second during maximal effort

what does FEV1 indicate

the severity of the obstructive disease

FEV1/FVC is the

percentage of the FVC expired in one second

in COPD, chronic

airway obstruction as an FEV1/FVC ratio is

<70%

what are volume time curves

plot of volume exhaled over time (spirometry)

what does a normal volume time curve look like

rise rapidly and smoothly

plateau within 3-4 seconds

types of PFTs

- Spirometry

- Plethysmography (lung volume assessment)

- Diffusing capacity

- 6 minute walk test (exercise testing)

- Peak flow

- bronchial provocation

what are flow volume curves / loops

diagram with flow on Y axis and volume expired on X axis

what does a normal flow volume curve look like

rapid rise, slow (almost linear) decline

what does bronchodilator reversibility measure

measures air movement in and out of lungs during forced maneuvers (spirometry) after inhalation of SABA (short acting B 2 agonist)

when are bronchodilator reversibility tests used

to measure disease responsiveness to bronchodilator therapy

pulse oximetry measures

oxygen saturation of blood (SpO2)

when is pulse oximetry used

any setting where hypoxemia can occur

what is a normal SpO2

>95%

what does body plethysmography measure

lung volumes

When is body plethysmography used?

When spirometry shows decreased FVC, but FEV1/FVC is within normal limits (suggests restrictive lung disease)

to identify air trapping or hyperinflation (obstructive)

tidal volume (TV)

amount of air that moves in and out of lung during inspiration

residual volume (RV)

air left in the lungs after a maximal expiratory effort

inspiratory reserve volume (IRV)

air inspired after maximal effort

expiratory reserve volume (ERV)

air expired after active expiratory effort

total lung capacity (TLC)

tidal volume (TV) + residual volume (RV) + inspiratory reserve volume (IRV) + expiratory reserve volume (ERV)

vital capacity (VC)

amount of air exhaled after a maximal inspiration

what does diffusion capacity (of the lung for carbon dioxide) measure

measure of gas exchange (DLco)

what is a normal DLco

>70% predicted

what causes decreased DLco

diseases with decreased blood flow or damaged alveoli

high DLco is representative of

asthma or pulmonary hemorrhage

normal DLco can be associated with what diseases

with restriction: morbid obesity, pleural effusion, neuromuscular weakness

with obstruction: asthma, chronic bronchitis

when is exercise testing used to assess pulmonary function

to confirm or rule out exercise induced bronchospasm and to evaluate effectiveness of medications

types of exercise tests used to assess pulmonary function

spirometry during exercise

six minute walk test

what does the bronchial provocation test measure

reactivity of airways to agents that induce airway narrowing

when are bronchial provocation tests used

-aid in asthma diagnosis (spirometry and symptoms not enough)

-evaluate drug therapy on airway hyperactivity

-evaluation of drug effectiveness

-when PFTs are normal but disease is suspected

what does peak expiratory flow rate (PEFR) measure

maximum airflow rate

when is PEFR used

to determine severity of asthma exacerbations

what do carbon monoxide breath tests measure

how much CO is in the lungs and how much is attached to Hgb in blood

what is a negative value for CO breath tests

< 10 ppm

what test is thought to motivate smokers in quitting

CO breath tests

also calculating lung age using FEV1

PFT results associated with chronic obstructive lung diseases

decreased: FEV1, FEV1/FVC

decreased/normal: FVC

normal/increased: RV, TLC

PFT results associated with reversible obstructive lung disease (asthma)

all results are normal

PFT results associated with restrictive lung diseases

decreased: FEV1, FVC, RV, TLC

normal/increased: FEV1/FVC

PFT results of mixed obstructive and restrictive lung diseases

decreased: FEV1, FVC, TLC

decreased/normal: FEV1/FVC

RV can be increased, normal, or decreased

urea is a byproduct of

hepatic protein metabolism

BUN represents

the concentration of nitrogen in the serum

prerenal causes of elevated BUN and SCr

Dehydration, blood loss, shock, CHF, hypotension

intrarenal causes of elevated BUN and SCr

Acute or chronic renal failure due to any cause, glomerulonephritis, acute tubular necrosis, severe hypertension

postrenal causes of elevated BUN and SCr

Obstruction of ureter, bladder neck, or urethra due to stones, enlarged prostate, or stricture

drugs that increase BUN

Corticosteroids, tetracyclines

ACE inhibitors, APAP, acyclovir, diuretics, antibiotics , NSAIDs

causes of low BUN

malnourishment, excess intravascular volume, liver damage

causes of low serum creatinine

aging, malnourishment

creatinine is a waste product of

creatine and creatine phosphate; produced in muscle

kidneys are responsible for maintaining

homeostasis within the body

-excretion of water/solutes

-maintain BP

-mineral metabolism

-RBC production

functional unit of kidneys

nephron

tubules of the kidney

Renal corpuscle → proximal convoluted tubule → nephron loop → distal convoluted tubule → collecting duct

normal GFR

about 125 mL/min

GFR is a measure

of kidney excretory function

exogenous markers of GFR

inulin clearance, Iothalamate and Cr-EDTA clearance

endogenous markers of GFR

cystatin C, serum creatinine, urea

what is the gold standard for measuring GFR in adults

inulin clearance

what is inulin

Fructose polysaccharide freely filtered through glomerulus without being metabolized, secreted, or absorbed

what does Iothalamate and Cr-EDTA clearance involve

Injection of radioactive marker, repeated blood sampling, and timed urine collection

inulin clearance normal ranges

Men: 125 + 15 (SD) mL/min/m2

Women: 110 + 15 (SD) mL/min/m2

normal range for Iothalamate and Cr-EDTA clearance

87-141 mL/min/SA

why is cystatin C considered more sensitive than serum creatinine in tracking changes to renal function

unaffected by diet and muscle mass

what is cystatin C

Indirect reflection of GFR

Protease inhibitor filtered by glomerulus but not reabsorbed or secreted

normal range for serum creatinine

0.6-1.2 mg/dL

normal range for blood urea nitrogen

8-23 mg/dL

BUN levels associated with uremic syndrome

>100 mg/dL

severe renal failure

azotemia

elevated BUN

there is an _______ relationship between SCr and renal function

inverse

direct measurement of creatinine clearance requires

24 hour urine collection

ways to estimate CrCl

Cockcroft - gault equation

MDRD equation

stage 1 of CKD

GFR (mL/min/1.73m2) = >90

Normal or kidney damage and normal GFR

stage 2 of CKD

GFR (mL/min/1.73m2) = 60-89

Slightly diminished GFR with kidney damage

stage 3 of CKD

GFR (mL/min/1.73m2) = 30-59

Moderately decreased GFR with kidney damage

stage 4 of CKD

GFR (mL/min/1.73m2) = 15-29

Significantly decreased GFR with kidney damage

stage 5 of CKD

GFR (mL/min/1.73m2) = <15

Kidney failure or on dialysis

three types of urinalysis testing

macroscopic, microscopic, chemical

macroscopic urinalysis considers

general appearance, color

microscopic urinalysis considers

cells, casts, crystals

chemical urinalysis considers

bile, protein, pH, specific gravity, bilirubin, urobilinogen, blood/hemoglobin, leukocyte esterase, nitrite, glucose, ketones