asthma in pregnancy

By La Lura White MD

Maternal Fetal Medicine

*ASTHMA IN PREGNANCY


*Asthma:

* Chronic disease.

*Increased airway responsiveness.

*Can occur spontaneously or in response to various stimuli.

* Physical exertion, allergens, medications, infection, emotions and stress.


* In response to contact with a triggering agents:

* Mast cells of the immune system, which are found in loose connective tissue release vasoactive chemical mediators:

*Histamine

*Bradykinin

*Leukotrienes

*Cytokines

* Prostaglands


* Mast cells cause neutrophils, lymphocytes and eosinophils to infiltrate the cells of the bronchial lining.

* Cause bronchoconstriction, vascular congestion and increases in capillary and mucosal edema.

* Impaired mucociliary action and increased mucus production and airway resistance.

*Airway obstruction that is partially or completely reversible.

*Development of symptoms.


*Symptoms:

* Wheezing

*SOB

*Cough

*Chest tightness

*Difficulty breathing


*Diagnosis:

*History of symptoms.

* Spirometry :evaluation: measures airflow

*Records the amount and the rate of air that you breathe in and out over a period of time.


*Volume-time curve: showing volume (liters) along the Y-axis and time (seconds) along the X-axis

*FEV1 is the volume of air that can forcibly be blown out in one second, after full inspiration


*Dx:

*Symptoms

*Improvement in FEV1 after administration of a short-acting inhaled B2-agonist.


*Asthma complicates 4–8% of pregnancies.

*Prevalence of and morbidity from asthma are increasing, although asthma mortality rates have decreased .

* Asthma symptoms peak in the late second or early third trimester. (29-36 weeks).

*Less severe during the last month of pregnancy.


*1/3 aggravate

*1/3 improve (gradual improvement throughout pregnancy)

*1/3 does not change

*Most return to their prepregnancy baseline within 3 months postpartum

*Most severe disease most likely to worsen during pregnancy

*The severity of symptoms in first pregnancy is similar in subsequent pregnancies.


*THE EFFECTS OF PREGNANCY ON ASTHMA

*Asthma has been associated with considerable maternal morbidity.

* In a large prospective study:

*Mild asthma had an exacerbation rate of 12.6% and hospitalization rate of 2.3%.

* Moderate asthma had an exacerbation rate of 25.7% and hospitalization rate of 6.8%.

* Severe asthmatics had exacerbation of 51.9% and hospitalization rate 26.9%.

* One of the most important conclusions to be made from this study is that pregnant asthmatic patients, even with mild or well-controlled disease, need to be monitored .


*Well-controlled, asthma can be associated with excellent maternal and perinatal pregnancy outcomes.

*Severe and poorly controlled asthma: (FEV1 < 80%)

* Increased prematurity

* Increased cesarean delivery rate

*Preeclampsia

*Growth restriction (SGA)

* Increased maternal morbidity/ mortality

*Hypertension

*Existing studies on the effects of asthma on pregnancy

*outcomes have had inconsistent results with regard to

*maternal and perinatal outcomes


*Risk Factors

*Younger

*Unmarried

*Lower socioeconomic status

*Ethinic: Hispanic, Latino or African-American

*Obesity


*National Asthma Education and Prevention Program (NAEPP)categorize asthma:

*Mild intermittent

*Mild persistent

*Moderate persistent

*Severe asthma


*Mild Intermittent Asthma

*Symptoms twice per week or less.

*Nocturnal symptoms twice per month or less.

*PEFR or FEV1 80% predicted or more

*Variability less than 20%


*Mild Persistent Asthma

*Symptoms more than twice per week but not daily.

*Nocturnal symptoms more than twice per month.

*PEFR or FEV1 80% predicted or more

*Variability 20–30%


*Moderate Persistent Asthma

*Daily symptoms

*Nocturnal symptoms more than once per week

*PEFR or FEV1 more than 60% to less than 80% predicted

*Variability more than 30%

*Regular medications necessary to control symptoms


*Severe Asthma

*Continuous symptoms and frequent exacerbations.

*Frequent nocturnal symptoms.

*PEFR or FEV1 60% predicted or less.

*Variability more than 30%.

*Regular oral corticosteroids necessary to control symptoms.


*Management Goal

*Treat airway inflammation.

* Decrease airway responsiveness.

* Prevent asthma symptoms and exacerbations.

*Maintain adequate oxygenation to the fetus by preventing hypoxic episodes in the mother.


*Optimal management:

*Avoiding or controlling asthma triggers (Allergens (pet dander, house dust, strong perfumes, smoking)

*85% of asthma patients test skin positive to common allergens.

*Allergen-impermeable pillow and mattress covers, weekly washing bedding in hot water, air sanitizers/humidifiers, leave when vaccuming is done, etc.


*Patient education:

*Teach early recognition of signs and symptoms.

*Improve compliance with medication.

*Seek prompt treatment when necessary.

*Prompt management of:

allergic rhinitis

sinusitis

gastroesophageal reflux

*May exacerbate asthma symptom.s


*Monitoring lung function:

*Spirometer

*FEV1 after a maximal inspiration is the single best measure of pulmonary function.

*The Peak Expiratory Flow Rate (PEFR) correlates well with the FEV1.

*Measured reliably with inexpensive, disposable, portable peak flow meters.

* Insight to course of asthma throughout the day.

*Help detect early signs of deterioration.

*Twice daily.

*Upon awakening and after 12 hr. *ASTHMA

IN PREGNANC

Y


*The typical PEFR in pregnancy should be 380–550 L/min.

*Patient should establish her “personal best” PEFR, then calculate her individualized PEFR.

*Green Zone more than 80% of personal best.

*Yellow Zone 50 to 80% of personal best.

*Red Zone less than 50% of personal best PEFR.


*Adequate pharmacologic therapy

*Well controlled:

*No limitations of activity.

*None or minimal daytime symptoms.

*No nocturnal symptoms.

*No (or minimal) need for rescue medication.

*Normal lung function.

*No exacerbations.


*Step wise management to therapy: step up to more intensive therapy if not controlled.

* Based on asthma severity (initial assessment.)

* Level of control (subsequent evaluations).

*Treat asthma aggressively.

*Attaining peak expiratory flow rate or forced expiratory volume in 1 second of 70% or > predicted value.

* ASTHMA IN PREGNANCY

*Step-care

*Use least amount of drug to control a patient’s asthma.

* Increases number and frequency of medications with increasing asthma severity.

* Safer to be treated appropriately than have asthma symptoms and exacerbations.

*Maintaining adequate oxygenation of the fetus.

*Prevention of hypoxic episodes in the mother.


*Pharmacology Management

*Relievers

*Controllers


*Relievers

*Bronchodilators: short-acting inhaled β 2-adrenergic receptor agonist used for the relief of bronchospasm.

*Short-acting: rapid relief of symptoms by relaxing airways and reducing bronchospasm.

*No anti-inflammatory action.

*They do not block the development of airway hyperresponsiveness.

*Ex: Albuterol (Proventil, Ventolin, Salbutamol)

* Metaproterenol (Alupent)


*Controllers:

*Control inflammation and treat disease.

*Reduce the risk of Asthma attack and airway remodeling.

*Mainly anti-inflammatory.

*Inhaled corticosteroids

*LABA

*Cromolyn

*Theophylline

*Leukotrene antagonists


*Glucocorticoids:

* Inhaled:

*Preferred treatment for all persistent asthma levels.

*Anti-inflammatory reduce pulmonary response to allergens.

*Beclomethasone (Qvar)

* ** Budesonide (Pulmicort) Class B

* Fluticasone (Flovent)


*Longer-acting bronchodilators. (LABA)

*Used for long term control of asthma, usually in combination with an inhaled glucocorticoid. (Advair, Symbicort).

*Not for rapid relief of symptoms.

*Ex: Salmeterol (Servent)

* Formoterol (Foradil)


*Cromolyn sodium:

* Is virtually devoid of significant side effects

*Blocks both the early and late phase pulmonary response to allergen challenge.

* Preventing the development of airway hyperresponsiveness.

*Alternative treatment for mild persistent asthma.

*Does not have any intrinsic bronchodilator or antihistaminic activity.


*Theophylline

* Alternative treatment for mild persistent.

* Adjunctive treatment for the management of moderate and severe persistent asthma during pregnancy.

*Adverse theophylline effects including, insomnia, heartburn, palpitations, and nausea, may be difficult to differentiate from typical pregnancy symptoms.

* High doses have been observed to cause jitteriness, tachycardia, and vomiting in mothers and neonates.

*New dosing guidelines have recommended that serum theophylline concentrations be maintained at 5–12 µg/mL during pregnancy.

(Yeh TF, Pildes RS. Transplacental aminophylline toxicity in a neonate [letter]. Lancet 1977;1:910).49


*Leukotriene Moderators

* Arachidonic acid metabolites reduce bronchospasm, mucous secretion and increased vascular permeabilit.y

*Improve pulmonary function significantly as measured by FEV1.

* An alternative treatment for mild persistent and an adjunctive treatment for the management of moderate and severe persistent asthma.

*Ex: zafirlukast (Accolate)

* montelukast (Singulair)

*Pregnancy category B.

* Minimal data regarding the efficacy or safety of these agents during human pregnancy.


*Mild intermittent

*Mild persistent

*Moderate persistent

*Severe persistent

*PRN Salbutamol

*Inhaled corticoteroid

*Inhaled corticoteroid + LABA

*Inhaled corticoteroid + LABA


*Oral Corticisreroids

*Burst may be needed for exacerbations.

*Especially if inciting incident can be identified.

*Oral prednisone 40-60 mg/d X 7 days

*Then taper over 7-14 days.

*Data on risk of congenital anomalies conflicting, ? Cleft lip/palate if < 13 weeks.


*Management

* Patients with moderate and severe asthma should be considered high risk for pregnancy complications.

*Adverse outcomes can be increased by underestimation of asthma severity and undertreatment of asthma.

* The first prenatal visit should include a detailed medical history with attention to medical conditions that could complicate the management of asthma, including active pulmonary disease.

* Question smoking history, presence and severity of symptoms, episodes of nocturnal asthma, days of work missed, emergency care visits, hospitalizations and intubations.

* The type and amount of asthma medications.


*Identifying and avoiding asthma triggers.

* Scheduling of prenatal visits based upon clinical severity

* Pulmonary function (FEV1 or PEFR) are recommended.

*Because asthma has been associated with intrauterine growth restriction and preterm birth, it is useful to establish pregnancy dating accurately

by first trimester ultrasonography where possible.


*Antepartum Survellience

*Pregnancies complicated by moderate or severe asthma:

* Ultrasound for fetal growth

*Antenatal assessment of fetal well-being (about 32 weeks).

*Asthma medications should be continued during labor.

*Encourage breastfeeding.


* Home Management of Asthma Exacerbations

*An asthma exacerbation that causes minimal problems for the mother may have severe sequelae for the fetus.

* Indeed, abnormal fetal heart rate tracing may be the initial manifestation of an asthmatic exacerbation.

*Therefore, asthma exacerbations in pregnancy should be aggressively managed.

*Patients should be given an individualized guide for decision making and rescue management.

* Educated to recognize signs and symptoms of early asthma exacerbations

such as coughing, chest tightness, dyspnea, or wheezing.

20% decrease in their PEFR.


*Patients should use inhaled albuterol 2–4 puffs every 20 minutes up to one hour.

*A good response is considered if symptoms are resolved or become subjectively mild and normal activities can be resumed.

* PEFR is more than 70% of personal best. May continue inhaled albuterol 2–4 puffs MDI every 3–4 hours as needed.

*The patient should seek further medical attention if the response is incomplete, or if fetal activity is decreased.


*Incomplete response:

*PEFR is 50–80% predicted.

* Persistent wheezing and shortness of breath, then repeat albuterol treatment 2–4 puffs MDI at 20-minute intervals up to two more times.

* If repeat PEFR 50–80% predicted or if decreased fetal movement, contact caregiver or go for emergency care.


*Poor response:

*PEFR less than 50% predicted, or severe wheezing and shortness of breath, or decreased fetal movement.

*Repeat albuterol 2–4 puffs by MDI and

obtain emergency care.


*Emergency Department and Hospital-Based Management of Asthma Exacerbation

*Initial assessment and treatment

• History and examination (auscultation, use of accessory muscles, heart rate, respiratory rate

*Peak expiratory flow rate (PEFR) or forced expiratory volume in 1 second (FEsaV1), oxygen saturation, ABG if < 95%.

* Initiate fetal assessment (consider fetal monitoring and/or biophysical profile if fetus is potentially viable)


*• Albuterol by metered-dose inhaler or nebulizer, up to three doses in first hour

*• Oral corticosteroid if no immediate response or if patient recently treated with systemic corticosteroid.

*• Oxygen to maintain saturation more than 95%

*• Repeat assessment: symptoms, physical examination, PEFR, oxygen saturation

*• Continue albuterol every 60 minutes for 1–3 hours provided there is improvement

*• Continue fetal assessment


*Good response

*• FEV1 or PEFR 70% or more

*• Response sustained 60 minutes after last treatment

*• No distress

*• Physical examination is normal

*• Reassuring fetal status

*• Discharge home


*Incomplete response

*• FEV1 or PEFR 50% or more but less than 70%

*• Mild or moderate symptoms

*• Continue fetal assessment until patient is stabilized

*• Monitor FEV1 or PEFR, oxygen saturation, pulse

*• Individualize decision for hospitalization


*Poor response

*• FEV1 or PEFR less than 50%

*• Pco2 more than 42 mm Hg

*• Physical examination: symptoms severe, drowsiness, confusion

*• Continue fetal assessment

*• Admit to intensive care unit Intravenous corticosteroid


*Early assessment

*Implement patient education and involvement

*Aggressively manage

*Close surveillance

*Aware of worsening conditions

*Treat all phases of asthma as potential complications

asthma in pregnancy

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