Journal Watch
description
Transcript of Journal Watch
Journal WatchJournal WatchJeffrey P Schaefer, MD
May 8, 2007
Today's ArticleToday's Article
• This article is ‘overwhelming’ !!!
BackgroundBackground• we believe that body organs
respond to emotional state
• asthma patients may experience ‘stress-associated breathlessness’ without increased airway obstruction
• mental state may alter measurements of breathing
ObjectivesObjectives• strained breathing may trigger
breathlessness in asthma patients
• asthma patents will feel more breathless with the same breathing pattern or with a stress induced breathing pattern
MethodsMethods• ‘Study of Harm’
– normals: exposure ? ‘disease’– asthma: exposure ? ‘disease’
• Exposure arithmetic task
• Disease altered breathing• breathlessness
PatientsPatients• Well Children 9-13 years (7)• Children with Asthma 9-14 yr (8)
– stable disease and free of infx x 1 mo– FEV1 > 70% of predicted– continue inhaled corticosteroid– STOP bronchodilator x 24 hr– informed consent
Exposure ‘subtraction’Exposure ‘subtraction’
MeasurementsMeasurements• magnetometer respiration band• electromyography electrodes• Borg breathlessness scale
ResultsResults
Timing of Resp Muscle Timing of Resp Muscle ActivityActivity
• Phase Angle– maximum EMG should occur at
maximum chest expansion
– at baseline:– asthmatic children
• reduce EMG activity earlier in inspiration• tend to have abdominal strain in
inspiration whereas normal have abdominal strain in expiration
• these effects diminish during arithmetic (distracted)
‘‘phase reversal’ with math*phase reversal’ with math*A & B* A & B* chest expansion chest expansion
C & D* C & D* frontal diaphragm EMG frontal diaphragm EMG
• no sig difference this was a ‘wash’
What does What does this all mean?this all mean?
Author’s remarksAuthor’s remarks• asthmatic children tend to ‘control
their breathing’ possibly to reduce turbulent airflow / irritation
• breathing became ‘closer to normal’ during arithmetic
• WHY?– distraction probably not– interaction between CNS and
breathing in the setting of disability?
• Are the results of the study valid?– comparison groups similar except for factor
under consideration?– similar measurements in both groups?– follow-up sufficient?– temporal relationship correct?– dose response gradient?
• What are the results?– association between exposure and outcome?– precision of risk estimate?
• Will the results help me in caring for my patients?– applicable to my practice?– magnitude of the risk?– stop the exposure?