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."

2 May 2023

5

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

May 2, 2023 10

DIFFERENTIAL DIAGNOSIS

All that wheezes is not asthma

CHF COPD Upper airway obstruction Tumor Laryngeal edema ...etc

2 May 2023

11

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

2 May 2023

20

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

2 May 2023

22

QUICK RELIEF ‘RELIEVER’ MEDICATIONS β2-agonists Salbutamol (Albuterol), terbutaline Methylxanthines Aminophylline, Theophylline Anticholinergics Ipratropium & Tiatropium bromide

MOA: Bronchodilators

2 May 2023

23

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

2 May 2023

24

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

2 May 2023

25

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

2 May 2023

26

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

2 May 2023

27

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

2 May 2023

28

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

2 May 2023

29

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.

2 May 2023

30

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

2 May 2023

31

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

2 May 2023

32

Disadv: Hep. Enz. Interact with the drugs metabolised by liver +ve responders < 50 % No response in 1 month STOP

2 May 2023

33

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