asthma in pregnancy dr muhammad akram khan qaim khani
TRANSCRIPT
ASTHMA IN PREGNANCY
BYDR MUHAMMAD AKRAM
MATERNITY AND CHILDREN HOSPITALMAUSADIA, JEDDAH
WHO DEFINITION OF ASTHMA "A chronic inflammatory disorder of the
airways in which many cells play a role, in particular mast cells, eosinophils, and T lymphocytes. In susceptible individuals this inflammation causes recurrent episodes of wheezing, breathlessness, chest tightness, and cough particularly at night and/or in the early morning. These symptoms are usually associated with widespread but variable airflow limitation that is at least partly reversible either spontaneously or with treatment. The inflammation also causes an associated increase in airway responsiveness to a variety of stimuli."
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Pathophysiology
A peak flow meter at home the convenience and ease of
use measure the PEFR (peak
expiratory flow rate) by taking a deep breath and then blowing into a tube on the meter as hard and as fast as patient can.
every day, sometimes several times a day, and keep track of these rates over time --are compared with charts that list normal values for sex, race, and height.
A spirometer in a doctor's office gives a more accurate measure of
lung function diagnose asthma, classify its severity,
and help decide what is the best way to treat asthma
done periodically The total volume patient exhale is
called "forced vital capacity," or FVC measures the volume of air patient
exhale in the first second. (This is referred to as "forced expiratory volume in one second," or FEV1.)
Patient will be given a bronchodilator and repeat the measerment
• You would not consider managing hypertension without a sphygmomanometer, or diabetes without a glucometer –
• accurate and objective assessmentand management of asthma is not possible without a spirometer or peak flow meter
The Peakflow or Peak Expiratory Flow or PEF indicates how severe the asthma crisis is:
PEF values to keep in mind :Normal for a man : 600 l/minNormal for a woman : 450 l/min
Values depending on severity (in % of normal value):
Acute asthma Serious crisis Light/moderate crisis
PEF impossibleor 30% ( 180 l/min)
PEF = 30 to 50%(180 to 300 l/min)
PEF 50%( 300 l/min)
MANAGING ASTHMA: PEAK FLOW CHART
People with moderate or severe asthma should take readings:Every morningEvery eveningAfter an
exacerbationBefore inhaling
certain medications
Source: “What You and Your Family Can Do About Asthma” by the Global Initiative For Asthma Created and funded by NIH/NHLBI
Sputum esinophilia.Chest X-Ray (For DD , complications).Skin tests (For Allergen Identification) .Bronchoprovocation (For Suspected Cases).
Several types of bronchoprovocation testing are available to assess airway responsiveness in specific patient situations, including pharmacologic challenge, exercise challenge, eucapnic voluntary hyperpnea, food additive challenge, and antigen challenge.
INVESTIGATIONS
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DIFFERENTIAL DIAGNOSIS
All that wheezes is not asthma
CHF COPD Upper airway obstruction Tumor Laryngeal edema ...etc
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Classification of Severity
CLASSIFY SEVERITYClinical Features Before Treatment
Symptoms NocturnalSymptoms
FEV1 or PEF
STEP 4Severe
Persistent
STEP 3Moderate Persistent
STEP 2Mild
Persistent
STEP 1Intermittent
ContinuousLimited physical activity
DailyAttacks affect activity
> 1 time a week but < 1 time a day
< 1 time a weekAsymptomatic and normal PEF between attacks
Frequent
> 1 time week
> 2 times a month
2 times a month
60% predictedVariability > 30%
60 - 80% predicted Variability > 30%
80% predictedVariability 20 - 30%
80% predictedVariability < 20%
The presence of one feature of severity is sufficient to place patient in that category.
GOALS OF THERAPY Minimal or no chronic symptoms day or night Minimal or no exacerbations No limitations on activities; no school/work
missed Maintain (near) normal pulmonary function Minimal use of short-acting inhaled beta 2
agonist Minimal or no adverse effects from
medications
STEPWISE APPROACH Review treatment every 1 to 6 months, and
gradually step down treatment If asthma controlled not maintained, then a
step up in treatment may be warranted
REASONS FOR POOR ASTHMA CONTROL Inhaler Technique Compliance Environment Also assess for an alternative diagnosis “All that wheezes is not asthma, and not all
asthma wheezes”
FACTORS AFFECTING COMPLIANCE Support of health care professional and
family Route of drug administration (inhaled vs.
oral) Complexity of drug regimens Side effects of medications $$ Cost $$
• Pregnancy does not increase the frequency or severity of asthma.• Progesterone reduces spasm and relaxes
smooth muscle. Bronchi are widened and mucus regulated. (Progesterone receptors are widely present in submucosal tissue.)
• Studies suggest that 11-18% of pregnant women with asthma will have at least one emergency department visit for acute asthma and of these 62% will require hospitalization1.
• One third of the asthmatic women feel better during pregnancy.
_______________________________________________________1. Schatz M, Zeiger RS, Hoffman CP, Harden K, Forsythe A, Chilingar L, et al.
Perinatal outcomes in the pregnancies of asthmatic women: a prospective controlled analysis. Am J Respir Crit Care Med 1995;151(4):1170-4
PHYSIOLOGICAL CHANGES IN RESPIRATORY SYSTEM IN PREGNANCY
Lung Volumes and Capacities Tidal volumes increases gradually(35-50%). Total lung capacity is reduced (4-5%) by the
elevation of the diaphragm. FRC (Functional Residual Capacity) and RV
(Residual Volume) decrease by about 20%.
Effects of Labour on the Pulmonary System There is a further decrease in FRC during the early
phase of each uterine contraction
ABG PREGNANT AND NON PREGNANT
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EFFECT OF ASTHMA ON PREGNANCYSPECIALLY IF UNTREATED WELLMATERNAL ED visits hospitalizations hyperemesis vaginal hemorrhage & accidental
haemorrhage due to severe coughing
CS respiratory failure PIH death
FETAL Oligohydroamnios LBW premature delivery fetal demise Meconium stainingNEONATAL neonatal hypoxemia low newborn
assessment scores perinatal mortality
DRUG THERAPY IN PREGNANCYIn general, the drugs used to treat asthma are
safe in pregnancy. Quick relief medications Long-term control medications
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QUICK RELIEF ‘RELIEVER’ MEDICATIONS β2-agonists Salbutamol (Albuterol), terbutaline Methylxanthines Aminophylline, Theophylline Anticholinergics Ipratropium & Tiatropium bromide
MOA: Bronchodilators
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LONG TERM ‘CONTROLLER ’ MEDICATIONS Corticosteroids Leukotriene modifiers Zafirlukast, Montelukast,Zileuton Mast cell stabilisers Nedocromil/Cromolyn Long acting β2-agonists Salmeterol, Formoterol, Bambuterol Methylxanthines Theophylline Anticholinergics Ipratropium bromide
Bronchodilators
MOA:
Prevent or reverse inflammation
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QUICK RELIEF AGONISTS MOA: 1. receptors G protein cAMP
Bronchodilatation 2. mucociliary transport 3. release of mediators Short acting (30-90 min.) (epinephrine,
isoproterenol, isoetharine) Adv: Immediate action Disadv: Only by inhalation or parenteral
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Long acting(4-6 h): Selective 2-agonists terbutaline, fenoterol, Salbutamol(albuterol)
Adv: Highly specific, No cardiac side effect except high doses
Can be given by all routes Disadv: Tremors Salbutamol: 2-4 mg oral, 0.5 mg im/s.c, 100-200 g/puff
Preferred route inhalation, equivalent to iv in severe asthma
Terbutaline: 0.25 mg sc or inhalation, 5 mg oral
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Ultra long(9 to 12 h): Salmeterol & formoterol
For nocturnal and exercise-induced asthma Adv: Anti-inflammatory activities Disadv: Not recommended for acute episodes Salmeterol: 25 g/puff MDI, 2 puffs BD.
‘SEROFLO’ ROTACAPS (Salm + fluticasone), MDI
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METHYLXANTHINESMedium potency bronchodilators with ? anti-inflammatory properties.
2nd line drugRarely used in acute conditionAdv: “Controller class”, Single evening dose nocturnal symptoms
Theophylline: 100-300 mg TDS Aminophylline: Slow iv 250-500 mg
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GLUCOCORTICOIDSInd: Acute illness with failure of optimal bronchodilators
Chronic disease with frequent recurrence & severity
Inhaled for long term control of asthma
Adv:Most potentMax. antiinflammatory
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MP Dose: 120-180 mg iv QD 7-60 mg daily OD am as needed for control Prednisolone Dose: 60 mg QDS. Taper ½ q 5th day after 10-12
days of acute episode S/E: Long delay to peak action Interrrupted growth, Gastric ulcer.
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Inhaled steroids Persistent symptoms & control
inflammation Facilitate the long-term prevention need for oral steroids Minimize acute occurrences &
hospitalizationsBeclomethasone: 100,200,250 gBudesonide: 200, 400 g BD- QIDFluticasone: 25,50,125 g inhalation,
rotacaps 100-250 g BD Dose needs to be individually titrated
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LEUKOTRIENE RECEPTOR ANTAGONISTS Zafirlukast, Montelukast, MOA: Inhibit or antagonise competitively against LTD4
receptor Modest bronchodilator to asthma exercise induced & nocturnal symptoms Montelukast: 10 mg OD Zafirlukast: 20 mg BD
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Disadv: Hep. Enz. Interact with the drugs metabolised by liver +ve responders < 50 % No response in 1 month STOP
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MAST CELL STABILISERSNedocromil Na, Cromolyn Na MOA: Inhibit degranulation of mast cells Reduce symptoms Lower airway reactivity Ind: Atopic patients with seasonal disease Exercise or cold induced asthma Adv: Can be given 15-20 minutes b/f contact as it can
abolish late reaction Cromolyn: 1mg/puff, 2 puffs QDS Nedocromil: 4 mg or 2 puffs BD
Steroid tablets Use as normal when indicated. Steroid tablets
should never be withheld because of pregnancy. First trimester exposure to oral steroids may
slightly increase the risk of cleft lip/palate2. The benefits of treatment outweigh the risks.
___________________________________2.Czeizel AE, Rockenbauer M. Population-based case control
study of teratogenic potential of corticosteroids. Teratology 1997;56(5):335-40.
Treatment ProtocolDIAGNOSIS BASED ON SYMPTOMS & OBJECTIVE ASSESSMENT
ASSESS SEVERITYMILD MODERATE SEVERE
ENVIRONMENTAL CONTROL AND EDUCATION
ADDITIONAL THERAPY
INHALED CORTICOSTEROIDS
INHALED SHORT-ACTING BETA2-AGONIST PRN
New Asthma Treatment Algorithm
BREAST FEEDING Women with asthma are encouraged to
breastfeed. Asthma medications are safe to be used as
normal during lactation.
SAFETY OF ASTHMA THERAPY DURING LACTATION(1)
SAFETY OF ASTHMA THERAPY DURING LACTATION(2)
MANAGEMENT OF ACUTE ASTHMA IN PREGNANCY Give drug therapy for acute asthma as for
the non-pregnant patient. High flow oxygen. Acute severe asthma in pregnancy is an
emergency and should be treated vigorously in hospital.
Continuous fetal monitoring
OBSTETRICAL MANAGEMENT• For induction of labor, oxytocin is preferred
over various prostaglandin (PG) preparations.• Intravaginal or intracervical PGE2 gel has not
been reported to cause bronchospasm but IV can cause
• Lumbar epidural analgesia reduces oxygen consumption and minute ventilation during the first and the second stages of labor and may considerably advantageous to patients with asthma
• If general anesthesia is needed:- Pretreatment with atropine may provide a bronchodilating effect.
- Ketamine is the agent of choice for anesthesia induction
• Use of non steroidal may be dangerous
General versus regional anesthesia
• Whenever possible if RA can do, it is preferred to general
• Avoid GA as possible in patients at risk of aspiration of gastric contents:
Emergency surgery in non fasting patient Gastroesophageal reflux Marked obesity Bowel obstruction Gastroparesis (trauma or diabetes) Pregnancy, or other factors increasing
intragastric pressure
DURING DELIVERY Only about 1 in 10 women with asthma have symptoms
during delivery. The increase in plasma epinephrine that occurs during
labor and delivery may contribute to the absence of asthma symptoms during this critical time period
MANAGEMENT DURING LABOUR Acute asthma is rare in labour. Continue usual asthma medications. Avoid general anesthesia if possible. Avoid prostaglandin F2α ( Dinoprost for induction )
and ergometrine (Synto) Women receiving steroid tablets at a dose
exceeding prednisolone 7.5mg per day for more than 2 weeks prior to delivery should receive parenteral hydrocortisone 100mg 6-8 hourly during labour.
ADVICE TO MOTHER Importance and safety of continuing their asthma
medications during pregnancy to ensure good asthma control.
The harm of severe or chronically under-treated asthma outweighs any small risk from the medications.
SELF-MANAGEMENT OF ASTHMA OUTPATIENT MANAGEMENT OF ASTHMA
Teach the patient self-management (Level of Evidence=A; The patient should have good knowledge of self-
management. The components of successful self-management are
acceptance of asthma and its treatment effective and compliant use of drugs
a PEF meter and follow-up sheets at home written instructions for different problems As a part of controlled self-management the patient can be
given a PEF follow-up sheet with individually determined alarm
limits and the following instructions (Level of Evidence=B; If the morning PEF values are 85% of the patient´s earlier
optimal value, the dose of the inhaled corticosteroid should be doubled for two weeks.
If the morning PEF values are below 50 - 70% of the optimal value the patient can start a course of prednisolon 40 mg daily for one week and contact the doctor by telephone.
REFERRENCE BRITISH GUIDELINE ON THE MANAGEMENT OF ASTHMA
(UPDATED 2009) UptoDate 2011 Asthma in Pregnancy by Timothy Hoskins, M.D.October 5,
2005