Basic information on the Graphics displayed on the Ventilators. Prepared to educate about the graphics to train the professionals who work with Ventilators.
Basic information on the Graphics displayed on the Ventilators. Prepared to educate about the graphics to train the professionals who work with Ventilators.
Reexpansion pulmonary edema is a serious complication after sudden expansion of collapsed lung.Re-expansion pulmonary edema is an uncommon complication following drainage of a pneumothorax , pleural effusion or removal of any space occupying lesion.
The incidence referred is less than 1%, andmortality can reach up to 20%.
Various types of Pulmonary function tests, physiology , how to do spirometry, how to interpret, precautions while doing it, newer pfts : described in this ppt.
Reexpansion pulmonary edema is a serious complication after sudden expansion of collapsed lung.Re-expansion pulmonary edema is an uncommon complication following drainage of a pneumothorax , pleural effusion or removal of any space occupying lesion.
The incidence referred is less than 1%, andmortality can reach up to 20%.
Various types of Pulmonary function tests, physiology , how to do spirometry, how to interpret, precautions while doing it, newer pfts : described in this ppt.
Knee anatomy and clinical tests 2024.pdfvimalpl1234
This includes all relevant anatomy and clinical tests compiled from standard textbooks, Campbell,netter etc..It is comprehensive and best suited for orthopaedicians and orthopaedic residents.
Explore natural remedies for syphilis treatment in Singapore. Discover alternative therapies, herbal remedies, and lifestyle changes that may complement conventional treatments. Learn about holistic approaches to managing syphilis symptoms and supporting overall health.
Recomendações da OMS sobre cuidados maternos e neonatais para uma experiência pós-natal positiva.
Em consonância com os ODS – Objetivos do Desenvolvimento Sustentável e a Estratégia Global para a Saúde das Mulheres, Crianças e Adolescentes, e aplicando uma abordagem baseada nos direitos humanos, os esforços de cuidados pós-natais devem expandir-se para além da cobertura e da simples sobrevivência, de modo a incluir cuidados de qualidade.
Estas diretrizes visam melhorar a qualidade dos cuidados pós-natais essenciais e de rotina prestados às mulheres e aos recém-nascidos, com o objetivo final de melhorar a saúde e o bem-estar materno e neonatal.
Uma “experiência pós-natal positiva” é um resultado importante para todas as mulheres que dão à luz e para os seus recém-nascidos, estabelecendo as bases para a melhoria da saúde e do bem-estar a curto e longo prazo. Uma experiência pós-natal positiva é definida como aquela em que as mulheres, pessoas que gestam, os recém-nascidos, os casais, os pais, os cuidadores e as famílias recebem informação consistente, garantia e apoio de profissionais de saúde motivados; e onde um sistema de saúde flexível e com recursos reconheça as necessidades das mulheres e dos bebês e respeite o seu contexto cultural.
Estas diretrizes consolidadas apresentam algumas recomendações novas e já bem fundamentadas sobre cuidados pós-natais de rotina para mulheres e neonatos que recebem cuidados no pós-parto em unidades de saúde ou na comunidade, independentemente dos recursos disponíveis.
É fornecido um conjunto abrangente de recomendações para cuidados durante o período puerperal, com ênfase nos cuidados essenciais que todas as mulheres e recém-nascidos devem receber, e com a devida atenção à qualidade dos cuidados; isto é, a entrega e a experiência do cuidado recebido. Estas diretrizes atualizam e ampliam as recomendações da OMS de 2014 sobre cuidados pós-natais da mãe e do recém-nascido e complementam as atuais diretrizes da OMS sobre a gestão de complicações pós-natais.
O estabelecimento da amamentação e o manejo das principais intercorrências é contemplada.
Recomendamos muito.
Vamos discutir essas recomendações no nosso curso de pós-graduação em Aleitamento no Instituto Ciclos.
Esta publicação só está disponível em inglês até o momento.
Prof. Marcus Renato de Carvalho
www.agostodourado.com
These lecture slides, by Dr Sidra Arshad, offer a quick overview of physiological basis of a normal electrocardiogram.
Learning objectives:
1. Define an electrocardiogram (ECG) and electrocardiography
2. Describe how dipoles generated by the heart produce the waveforms of the ECG
3. Describe the components of a normal electrocardiogram of a typical bipolar leads (limb II)
4. Differentiate between intervals and segments
5. Enlist some common indications for obtaining an ECG
Study Resources:
1. Chapter 11, Guyton and Hall Textbook of Medical Physiology, 14th edition
2. Chapter 9, Human Physiology - From Cells to Systems, Lauralee Sherwood, 9th edition
3. Chapter 29, Ganong’s Review of Medical Physiology, 26th edition
4. Electrocardiogram, StatPearls - https://www.ncbi.nlm.nih.gov/books/NBK549803/
5. ECG in Medical Practice by ABM Abdullah, 4th edition
6. ECG Basics, http://www.nataliescasebook.com/tag/e-c-g-basics
Prix Galien International 2024 Forum ProgramLevi Shapiro
June 20, 2024, Prix Galien International and Jerusalem Ethics Forum in ROME. Detailed agenda including panels:
- ADVANCES IN CARDIOLOGY: A NEW PARADIGM IS COMING
- WOMEN’S HEALTH: FERTILITY PRESERVATION
- WHAT’S NEW IN THE TREATMENT OF INFECTIOUS,
ONCOLOGICAL AND INFLAMMATORY SKIN DISEASES?
- ARTIFICIAL INTELLIGENCE AND ETHICS
- GENE THERAPY
- BEYOND BORDERS: GLOBAL INITIATIVES FOR DEMOCRATIZING LIFE SCIENCE TECHNOLOGIES AND PROMOTING ACCESS TO HEALTHCARE
- ETHICAL CHALLENGES IN LIFE SCIENCES
- Prix Galien International Awards Ceremony
Acute scrotum is a general term referring to an emergency condition affecting the contents or the wall of the scrotum.
There are a number of conditions that present acutely, predominantly with pain and/or swelling
A careful and detailed history and examination, and in some cases, investigations allow differentiation between these diagnoses. A prompt diagnosis is essential as the patient may require urgent surgical intervention
Testicular torsion refers to twisting of the spermatic cord, causing ischaemia of the testicle.
Testicular torsion results from inadequate fixation of the testis to the tunica vaginalis producing ischemia from reduced arterial inflow and venous outflow obstruction.
The prevalence of testicular torsion in adult patients hospitalized with acute scrotal pain is approximately 25 to 50 percent
Couples presenting to the infertility clinic- Do they really have infertility...Sujoy Dasgupta
Dr Sujoy Dasgupta presented the study on "Couples presenting to the infertility clinic- Do they really have infertility? – The unexplored stories of non-consummation" in the 13th Congress of the Asia Pacific Initiative on Reproduction (ASPIRE 2024) at Manila on 24 May, 2024.
Title: Sense of Taste
Presenter: Dr. Faiza, Assistant Professor of Physiology
Qualifications:
MBBS (Best Graduate, AIMC Lahore)
FCPS Physiology
ICMT, CHPE, DHPE (STMU)
MPH (GC University, Faisalabad)
MBA (Virtual University of Pakistan)
Learning Objectives:
Describe the structure and function of taste buds.
Describe the relationship between the taste threshold and taste index of common substances.
Explain the chemical basis and signal transduction of taste perception for each type of primary taste sensation.
Recognize different abnormalities of taste perception and their causes.
Key Topics:
Significance of Taste Sensation:
Differentiation between pleasant and harmful food
Influence on behavior
Selection of food based on metabolic needs
Receptors of Taste:
Taste buds on the tongue
Influence of sense of smell, texture of food, and pain stimulation (e.g., by pepper)
Primary and Secondary Taste Sensations:
Primary taste sensations: Sweet, Sour, Salty, Bitter, Umami
Chemical basis and signal transduction mechanisms for each taste
Taste Threshold and Index:
Taste threshold values for Sweet (sucrose), Salty (NaCl), Sour (HCl), and Bitter (Quinine)
Taste index relationship: Inversely proportional to taste threshold
Taste Blindness:
Inability to taste certain substances, particularly thiourea compounds
Example: Phenylthiocarbamide
Structure and Function of Taste Buds:
Composition: Epithelial cells, Sustentacular/Supporting cells, Taste cells, Basal cells
Features: Taste pores, Taste hairs/microvilli, and Taste nerve fibers
Location of Taste Buds:
Found in papillae of the tongue (Fungiform, Circumvallate, Foliate)
Also present on the palate, tonsillar pillars, epiglottis, and proximal esophagus
Mechanism of Taste Stimulation:
Interaction of taste substances with receptors on microvilli
Signal transduction pathways for Umami, Sweet, Bitter, Sour, and Salty tastes
Taste Sensitivity and Adaptation:
Decrease in sensitivity with age
Rapid adaptation of taste sensation
Role of Saliva in Taste:
Dissolution of tastants to reach receptors
Washing away the stimulus
Taste Preferences and Aversions:
Mechanisms behind taste preference and aversion
Influence of receptors and neural pathways
Impact of Sensory Nerve Damage:
Degeneration of taste buds if the sensory nerve fiber is cut
Abnormalities of Taste Detection:
Conditions: Ageusia, Hypogeusia, Dysgeusia (parageusia)
Causes: Nerve damage, neurological disorders, infections, poor oral hygiene, adverse drug effects, deficiencies, aging, tobacco use, altered neurotransmitter levels
Neurotransmitters and Taste Threshold:
Effects of serotonin (5-HT) and norepinephrine (NE) on taste sensitivity
Supertasters:
25% of the population with heightened sensitivity to taste, especially bitterness
Increased number of fungiform papillae
micro teaching on communication m.sc nursing.pdfAnurag Sharma
Microteaching is a unique model of practice teaching. It is a viable instrument for the. desired change in the teaching behavior or the behavior potential which, in specified types of real. classroom situations, tends to facilitate the achievement of specified types of objectives.
ARTIFICIAL INTELLIGENCE IN HEALTHCARE.pdfAnujkumaranit
Artificial intelligence (AI) refers to the simulation of human intelligence processes by machines, especially computer systems. It encompasses tasks such as learning, reasoning, problem-solving, perception, and language understanding. AI technologies are revolutionizing various fields, from healthcare to finance, by enabling machines to perform tasks that typically require human intelligence.
3. INDICATIONS FOR
PULMONARY FUNCTION TEST
• Detect mechanical dysfunction of the respiratory system
• Quantify the degree of dysfunction detected
• Define the nature of dysfunction
– Obstructive
– Restrictive
– Mixed
• Follow the course of diseases
• Evaluate the effect of therapeutic interventions
Kendig’s Disorders of the Respiratory Tract in Children 8th Edition
4. INDICATIONS FOR SPIROMETRY
• Diagnostic:
– To evaluate symptoms, signs or abnormal laboratory tests
– To measure the effect of disease on pulmonary function
– To screen individuals at risk of having pulmonary disease
– To assess pre-operative risk
– To assess prognosis
– To assess health status before beginning strenuous physical activity
program
Eur Respir J 2005: 26: 319-338.
5. INDICATIONS FOR SPIROMETRY
• Monitoring:
– To assess therapeutic intervention
– To describe the course of disease that affect lung function
– To monitor people exposed to injurious agents
– To monitor for adverse reactions to drugs with known pulmonary toxicity
• Disability/impairment evaluations
– To assess patients as part of a rehabilitation program
– To assess risks as part of an insurance evaluation
– To assess individuals for legal reasons
Eur Respir J 2005: 26: 319-338.
6. INDICATIONS FOR SPIROMETRY
• Public health
– Epidemiological surveys
– Derivation of reference equations
– Clinical research
Eur Respir J 2005: 26: 319-338.
9. SPIROMETRY
• Volume displacement spirometer
– Water seal spirometer
– Dry rolling seal spirometer
– Bellows-Type Spirometers
• Flow-sensing spirometer
– Pneumotachometer or pressure differential type
– Thermistor , hot-wire anemometer
– Turbine flow sensor
– Ultrasonic flow sensor
Jones and Bartlett. Chapter1: Forced Spirometry and Related Tests
10. SPIROMETRY IN CHILDREN
• Age at least 5-6 years up
– Ability to perform maneuver follow command
– Able to take deep breaths, cough and blowout forcefully
• Experienced technicians
• Environment:
- Bright, pleasant atmosphere
- Quiet and free of distraction
- Room not use for other unpleasant procedure
- May be permit parents in room (but not disturb the test)
Kendig’s Disorders of the Respiratory Tract in Children 8th Edition
11. SUBDIVISIONS OF LUNG VOLUME
Kendig’s Disorders of the Respiratory Tract in Children 8th Edition
12. PROCEDURES FOR RECORDING
FORCED VITAL CAPACITY
• Check the spirometer calibration
• Explain the test Prepare the subject
• Ask about smoking, recent illness, medication use, etc.
– Measure weight and height without shoes
• Wash hands
• Instruct and demonstrate the test to the subject, to include
– Correct posture with head slightly elevated
– Inhale rapidly and completely
– Position of the mouthpiece (open circuit)
– Exhale with maximal force
ATS/ERS Task Force Standardization of Spirometry, Eur Resp J 2005.
13. • Perform maneuver (closed circuit method)
• Have subject assume the correct posture
• Attach nose clip, place mouthpiece in mouth and close lips around the
mouthpiece
• Inhale completely and rapidly with a pause of ,1 s at TLC
• Exhale maximally until no more air can be expelled while maintaining an upright
posture
• Repeat instructions as necessary, coaching vigorously
• Repeat for minimum of 3 maneuvers; no more than 8
• Check test repeatability and perform more maneuvers as necessary
ATS/ERS Task Force Standardization of Spirometry, Eur Resp J 2005.
PROCEDURES FOR RECORDING
FORCED VITAL CAPACITY
14.
15. INTERPRETING PFT
1. Acceptability of test
2. Flow volume curve/loop
3. Parameter
– FVC
– FEV1
– FEV1/FVC ratio
– FEF25-75%
4. Reversibility
17. FREE FROM ARTIFACT
– No cough, early terminate
– Maximal effort
– No leak, obstructed mouthpiece
ATS/ERS Task Force Standardization of Lung Function Test, Eur Resp J 2005.
19. START OF TEST CRITERIA
• Extrapolated volume < 5% of FVC or 0.15 L (which is greater)
ATS/ERS Task Force Standardization of Lung Function Test, Eur Resp J 2005.
20. END OF TEST CRITERIA
1) Cannot or should not continue further exhalation: marked discomfort, near
syncope
2) No change in volume-time curve (< 0.025 L) for at least 1 sec and exhaled
duration
≥ 3 sec in children < 10 yr
≥ 6 sec in children > 10 yr
ATS/ERS Task Force Standardization of Lung Function Test, Eur Resp J 2005.
21. INTERPRETING PFT
1. Acceptability of test
2. Flow-Volume curve/loop
3. Parameter
– FVC
– FEV1
– FEV1/FVC ratio
– FEF25-75%
4. Reversibility
22. QUALITY OF FLOW-VOLUME LOOP
(a) a rapid rising to peak
flow
(b) fairly smooth curve,
continuous decrease in
flow
(c) terminates at a flow
within 0 to 0.1 L/s of
zero flow or ideally at
zero flow
TLC
RV
Kendig’s Disorders of the Respiratory Tract in Children 8th Edition
23. FLOW-VOLUME CURVE
Steep slope and decrease volume Scoop out with decrease slope
Restrictive lung defect Obstructive lung defect
24.
25.
26. INTERPRETING PFT
1. Acceptability of test
2. Flow volume curve/loop
3. Parameter
– FVC
– FEV1
– FEV1/FVC ratio
– FEF25-75%
4. Reversibility
27. FORCED VITAL CAPACITY (FVC)
“Maximal volume of air exhaled from maximally forced
expiration as effort from a maximal inspiration”
• Normal host: FVC ~ VC (difference < 200 ml)
• Depend on effort and adequate exhalation
Disease with low FVC
- Restrictive lung disease from chest wall, lung parenchyma,
respiratory muscle
- Severe airflow obstruction with air trapping
- Inadequate exhalation
28. FORCED EXPIRATORY VOLUME IN
1 SEC (FEV1)
“Maximal volume of air exhaled in first second of forced expiration”
• Less variation (normal 10-15%)
• Good correlation with PEFR
• Good for diagnosis, follow up and evaluate reversibility
Disease with low FEV1
• obstructive lung disease (large airway)
• restrictive lung disease from chest wall, lung parenchyma,
respiratory muscle
• increase age, poor effort
31. FEV1/FVC RATIO (FEV1%)
“Maximal volume of air exhaled in the first second of forced expiration
compared to FVC”
• More sensitive than FEV1 for detecting mild airway obstruction
• More variation than FEV1 less benefit for F/U or assess reversibility
test
• Advantage for DDx obstructive and restrictive lung disease
33. NORMAL VALUES OF LUNG
FUNCTION
• <80% predicted is still quite commonly applied to FVC, FEV1,TLC, etc.
• Fixed values (80% of predicted FVC, 0.7 for FEV1/FVC) estimated based on
middle age adults, erroneous clinical decision in children, sex bias
• Using reference data in interpretation of results
– z-score (-1.645) = 5th percentile Lower limit of normal
– The true LLN = age- and/or height-dependent, varying percent values in
different individuals
ARCCM Vol.196 Dec 1, 2017.
35. FORCED EXPIRATORY FLOW RATE
AT 25-75% OF FVC (FEF 25-75%)
“Mean forced expiratory flow between 25% and 75% of the FVC”
• Maximum mid-expiratory flow
• The hypothesis that reduced mid-expiratory flow =specific for
small airways disease has been shown to be incorrect
• The limitation of instantaneous and mid expiratory flows: make
the recommendation to disregards this value
• Discordance between FEF25-75% and FEV1 to detect air flow
obstruction
Eur Respir J 2014; 43: 1051-1058.
36. FEF 25-75%
FVC
Calculated by determining the slope of the line drawn connecting
points on the spirogram at 25% to 75% of expiratory vital capacity
△V
△T
38. SEVERITY OF DYSFUNCTION
Parameters Obstructive
(FEV1)
Restrictive
(TLC)
Normal ≥ 80% ≥ 80%
Mild 60-79% 70-79%
Moderate 40-59% 50-69%
Severe < 40% < 50%
Kendig’s Disorders of the Respiratory Tract in Children 7th Edition 2006
39. INTERPRETING PFT
1. Acceptability of test
2. Flow volume curve/loop
3. Parameter
– FVC
– FEV1
– FEV1/FVC ratio
– FEF25-75%
4. Reversibility
40. AIRWAY REACTIVITY TEST
• Bronchodilator challenge “reversibility test”
- most choice of an aerosolized bronchodilator (albuterol, metaproterenol,
isoetharine, isoproterenol, or ipratropium bromide)
• Bronchoconstrictor challenge: methacholine challenge test, histamine,
leukotriene, prostaglandin
• Exercise challenge
Kendig’s Disorders of the Respiratory Tract in Children 8th Edition
41. REVERSIBILITY TESTING
• Post-bronchodilator response
• Method:
1. Three acceptable tests of FEV1, FVC and PEF recorded
2. Inhaled bronchodilator administration
• 100 mcg of Albuterol / Salbutamol X 4 doses (30 sec interval) (4
puff of salbutamol)
• Anticholinergic agent (ipratropium bromide) 40 mcg X 4 doses
3. Three additional acceptable tests are recorded
• 10-15 min later for short-acting B2 agonists
• 30 min later for short-acting anticholinergic agents
ATS/ERS Task Force Standardization of Lung Function Test, Eur Resp J 2005.
42. PREPARING BEFORE REVERSIBILITY
TEST
Medications Time to withhold (hr)
Regular β2 agonist 4-8
Ipratropium bromide 4-8
Cromolyn sodium 8-12
Sustained action β2 agonist 12
Methylxanthines 12
Slow-release methylxanthines 24
Inhaled steroids no need
43. % Change = Postdrug – Predrug
Predrug
x 100
Parameters Minimum significant changes from
baseline (%)
FVC +10
FEV1 +12
FEF25-75% + 25
PEFR + 12
Pediatr Clin North Am 1992; 39:1243-59.
Post drug test : PFT at 15 minutes after inhaled bronchodilator inhalation
BRONCHODILATOR RESPONSE TEST
45. CLINICAL APPLICATIONS OF PEAK
FLOW METER
• Serial measurements of PEFR are essential
• Monitoring, not diagnostic
• Single value is of very limited use
• Highly effort dependent
• Height variation
46. INDICATION FOR USE PEAK FLOW
METER
Asthma (age > 5yr, moderate to severe)
Consider long-term daily peak flow monitoring:
—moderate or severe persistent asthma (Evidence B)
—history of severe exacerbations (Evidence B)
—patients who poorly perceive airflow obstruction and
worsening asthma (Evidence D)
47. TECHNIQUE
• The peak flow meter should read zero
• Standing up straight or sitting upright
• Take in as deep a breath as possible
• Place the peak flow meter in the mouth, with the tongue
under the mouthpiece
• Close the lips tightly around the mouthpiece
• Blow out as hard and fast as possible
• Write down the number obtained
• Repeat the process two more times.
Write down the highest number obtained.
Do not average the numbers
48. PEFR (L/Min) = [ 5 x Height (cm) ] - 400
Polgar G., Promadhat V., Pulmonary function
testing in children: techniques and standards.
Philadelphia: WB Saunders, 1971
49. PEFR INTERPRETATION
Zone PEFR
(% Personal best)
Actions
GREEN 80-100 Continue routine Rx
↓ meds
YELLOW
(Acute exacerbation)
50-80 ↑ Rx
↑ maintenance Rx
RED
(Severe exacerbation)
<50 Immediate
bronchodilator, call Dr. if
no improvement
50. DIURNAL VARIATION OF PEFR
Daily variability (%) = PEFRevening- PEFRmorning x 100
½ (PEFRmorning + PEFRevening )
more than 20% indicates a poor controlled asthma
54. INTERPRETATION
Condition VA KCO or DLCO/VA DLCO
Incomplete lung
expansion
Discrete loss of alveolar
units
Diffuse loss of alveolar
units
Emphysema
Pulmonary vascular
disease
Normal
High pulmonary blood
volume
Normal
Alveolar hemorrhage
55. SEVERITY CLASSIFICATION
• Normal DLCO 80 – 120% of predicted
• Grades of severity in DLCO reduction
• Diffusion defect
Grading DLCO
(%Predicted)
Normal > 80
Mild 60 – 80
Moderate 40 – 60
Severe < 40
56. • ↑ Chemical reaction between Hb and CO
– Polycythemia
– Left-to-right shunt
– Increase cardiac output
– Pulmonary / alveolar hemorrhage
– ↓ FiO2
– Exercise immediately before DLCO test
– Supine position
– Obesity
– Increase altitude
HIGH DLCO ADJUSTED
57. LOW DLCO ADJUSTED
• ↓ Membrane transfer
– ↓ Respiratory effort
– Respiratory m. weakness
– Thoracic deformity
preventing full inflation
– Interstitial disease
– Lung resection
– Emphysema
– Smoking
• ↓ Chemical reaction
between Hb and CO
• Anemia
• Pulmonary emboli
• ↑HbCO
• ↑Inspired O2 (FiO2)
• Combined
• Pulmonary edema
• Pulmonary vasculitis
• Pulmonary hypertension
59. AIRWAY HYPERRESPONSIVENESS
• Airway hyperresponsiveness (AHR) to exogenous stimuli - characteristic
feature of asthma
• When assessed with nonselective direct-acting stimuli such as histamine or
methacholine - defined as increase in both magnitude and the ease of induced
bronchoconstriction
Middleton’s 8th Edition
60. AIRWAY HYPERRESPONSIVENESS
• Increase in the magnitude of
bronchoconstriction = progressive elevation of
the plateau response on the concentration-
response (or dose-response) curve
• Increase in the ease of developing
bronchoconstriction = leftward shift of the
concentration response curve.
• Left shift = reduced provocation concentration
or dose producing a 20% fall in forced
expiratory volume in 1 second (FEV1), called
PC20 or PD20
• Hyperresponsiveness measured by the PC20 or
PD20 reflecting the leftward shift of the curve
Middleton’s 8th Edition
61. INDICATIONS
• To exclude or confirm a suspected diagnosis of asthma (when inconclusive
spirometry, especially in those with normal or near-normal lung function
values)
• Screening applicants for situations where AHR would present a high safety
risk, such as commercial diving, submarine service and some occupational
exposures
• Diagnosis of occupational asthma (specific inhalation challenges)
Eur Respir J 2017.
67. BRONCHIAL PROVOCATION TEST
• Bronchoconstrictor challenge: methacholine
• Methacholine from 0.0625 - 16 mg/mL are given by nebulization
in stepwise progression
• Pulmonary function at baseline and after each increasing dose of
methacholine until FEV1 decreases by 20% or the maximum dose
(16 mg/mL) is reached
Result: dose of methacholine that produce decline 20% of FEV1 >> lower
dose indicative of greater degrees of airway response
Kendig’s Disorders of the Respiratory Tract in Children 8th Edition
72. DIRECT CHALLENGE TESTS
• AHR increase: inflammatory stimuli (and allergens), occupational sensitizers, viral infections
• AHR improve: environmental control, anti-inflammatory medications, spontaneously
• Deep inhalations to TLC followed by a breathhold causes bronchoprotection in asthmatic patients
with mild AHR (e.g., PC20 > 2 mg/mL) false-negative
• Pediatrics population – age > 6 years, cut points same as adults
• 3 Important points for interpretation of direct (methacholine) challenges
– Normal FEV1
– Requirement of clinical currency and exposures (past few days) of suspicious symptoms
– Avoidance of deep inhalation during methacholine inhalation
Middleton’s 8th Edition
73. INDIRECT CHALLENGE TESTS
• Direct challenges more sensitive
• Indirect challenges more specific for asthma, probably correlate
better with asthma severity, activity
Middleton’s 8th Edition
75. EXERCISE-INDUCED
BRONCHOCONSTRICTION
• Single, relatively high-dose challenge of near-maximal exercise for about 6 minutes
• Treadmill (> cycle ergometer)
• Dry and cool air (< 50% relative humidity, < 25 C)
• Target HR = 80 - 90% of predicted maximum (220 - age)
Positive: > 10% drop of FEV1
Middleton’s 8th Edition
76. EUCAPNIC VOLUNTARY HYPERPNEA
• Inhale dry air with 5% CO2 for 6 minutes, targeting a minute ventilation of 30 × FEV1,
equivalent to 85% of the calculated maximum voluntary ventilation (MVV)
• Measure FEV1 before and after EVH for up to 10 or 15 minutes
Positive: > 10% drop of FEV1
• Mechanism of bronchoconstriction: osmotic challenge from excessive drying of airway mucosa
same to EIB
• EVH - current test of choice recommended by the International Olympic Committee for the
assessment of athletes with EIB
Middleton’s 8th Edition
77. HYPERTONIC SALINE
• Indirect challenges more specific for asthma, probably correlate better with asthma severity,
activity complementary to hi
• Inhaling 4.5% saline from a high-output ultrasonic nebulizer (1-2 mL/min) for doubling
amounts of time ranging from 0.5-8 minutes
• Measure FEV1 at time points similar to those of the histamine and methacholine challenges
• Mechanism of bronchoconstriction: osmotic effect
Middleton’s 8th Edition
78. ADENOSINE CHALLENGE
• Adenosine or adenosine monophosphate nonosmotic release of mast cell mediators
• Methods identical to that for histamine and methacholine except for concentrations used
(doubling concentrations up to 400 mg/mL)
Middleton’s 8th Edition
79. DRY POWDER MANNITOL
• Osmotic challenge
• The doses are 0 (placebo control), 5, 10, 20, 40, 80, 160, 160, and 160 mg, giving a cumulative
dose-response curve ranging from 0 to 635 mg
• Endpoint = targeted 15% fall in FEV1 measured 1 minute after each dose
• Interval between doses should be 2 minutes or only slightly longer
• Mannitol PD15 > 635 mg = Normal
Middleton’s 8th Edition
81. SUMMARY
• Direct (e.g., methacholine) challenges with no deep inhalations - tests of choice
Negative: rule out clinically current asthma with reasonable certainty
Positive: support a diagnosis of asthma
• Negative direct challenges in possible EIB should be followed by more specific test
• Indirect challenges (e.g., EVH, mannitol) - tests of choice
– Assess EIB especially for regulatory agencies (e.g., athletic, military, SCUBA diving)
– Assess asthma control, monitoring asthma treatment
– Differentiating asthma from other airway disease (COPD)
– Inferring exposure to a sensitizer in evaluation of occupational asthma
• Positive indirect challenge and a methacholine PC20 < 1 mg/mL (normal spirometry) probably high
specificity and PPV for asthma
Middleton’s 8th Edition