Asthma in Pregnancy. Asthma. Chronic Airway Inflammation. Objective Measures of Airflow. Peak exp. flow rate (PEFR)

Transcription

1 Chronic Airway Inflammation Asthma in Pregnancy Robin Field, MD Maternal Fetal Medicine Kaiser Permanente San Francisco Asthma Chronic airway inflammation increased airway responsiveness to a variety of stimuli airflow obstruction that is partially or completely reversible Dx: Episodic symptoms of airway obstruction & objective measure of reversible airway obstruction Prevalence and morbidity from asthma increasing Asthma occurs in 4 8 % of pregnancies Objective Measures of Airflow Forced expiratory volume in 1 second (FEV 1 ) Single best measure of airflow Requires spirometry Peak exp. flow rate (PEFR) Measures large airway function PEFR correlates well with FEV 1 Measured with inexpensive peak flow meter Predicted values: l/min PEFR doesn t change during pregnancy 1

2 Management Principals of Asthma During Pregnancy Incidence of Asthma Attacks (Thorax 1996; 51:411) Objective monitoring of lung function Avoiding or controlling asthma triggers Patient education Individualized pharmacologic treatment Inhaled corticosteroids preferred Step-care therapeutic approach Ultimate goal: prevent hypoxic episodes Persistent Asthma Class and Complication Rates (Schatz. J Allergy Clin Immun. 2003, 112:283) Severity Classification Exacerbation Rate Hospitalization Rate Mild 12.6% 2.3% Moderate 29.7% 6.8% Severe 51.9% 26.9% Mild Intermittent Asthma Symptoms: twice per week or less Nocturnal Symptoms: 2x per month Lung Function: FEV 1 or PEFR 80% predicted PEFR variability < 20% 2

3 Mild Persistent Asthma Symptoms >2x per week but <1 a day Exacerbations may affect activity Nocturnal symptoms: > 2x per month Lung function: FEV 1 or PEFR 80% predicted PEFR variability 20-30% Moderate Persistent Asthma Daily symptoms Regular medications necessary to control symptoms Nocturnal symptoms: > 1 x per week Lung function FEV 1 or PEFR 60-80% predicted PEFR variability >30% Severe Persistent Asthma Continuous symptoms Frequent exacerbations Regular oral corticosteroids needed to control symptoms Frequent nocturnal symptoms Lung function FEV 1 or PEFR <60% predicted PEFR variability >30% Asthma: Pharmacologic Therapy Long - term control medications Anti-inflammatory agents most effective Inhaled corticosteroids Quick - relief medications Short-acting inhaled β 2 -agonists Use of > canister a month indicates need to intensify anti-inflammatory medications Step-care approach to asthma therapy 3

4 Asthma: Patient Education Basic facts about asthma Roles of medication Self monitoring Skills: inhaler use Environmental control measures When & how to take rescue measures Common Triggers of Asthma Infections URI sinusitis Allergens pollens dust mites danders cockroach antigens Occupational agents Exercise Irritants tobacco smoke air pollutants Drugs NSAIDs beta blockers Food additives Weather GERD Menses Asthma Therapy In Pregnancy Tailor therapy to individual needs Integrate asthma care with OB care Asses asthma status during OB visits Use step-care approach to therapy Preference for inhalation drugs Preference for drugs with long history of use during pregnancy Asthma Therapy in Pregnancy (NIH NAEPP Treatment Update 2004) Anti-inflammatory agents inhaled corticosteroids Budesonide preferred during pregnancy Cromolyn sodium oral corticosteroids Bronchodilators short acting inhaled beta 2 agonists Albuteral perferred during pregnancy long acting bronchodilators Salmeteral or formoterol 4

5 Inhaled Corticosteroids Most effective medication for the long-term control of persistent asthma No significant risk of systemic effects in low to medium doses Adverse effects are minimized by use of spacer with MDI, and rinsing mouth Not equipotent on a microgram basis Brand Names of Common Inhaled Corticosteroids Beclomethasone: - Beclovent, Vanceril, QVAR Triamcinolone: Azmacort Budesonide: Pulmicort Fluticasone: Flovent Flunisolide: AeroBid Metered Dose Inhaler: MDI Common Inhaler Mistakes Failure to exhale before breathing in Inhaling too fast Breathing in through nose Breathing in first, activating second Stop breathing in after activation Pressing inhaler repeatedly during breath in Uneven and/or too shallow inhalation 5

6 MDI with Spacer Tube Brand Names of Some Typical Asthma Meds (FDA category) Albuterol MDI (C): Proventil, Ventolin Metaproterenol MDI (C): Alupent Salmeterol MDI (C): Seravent Theophylline (C): Slo-bid, Theo-Dur Montelukast (B): Singulair Zafirlukast (B): Accolate Zileuton (C): Zyflo General Principles of Asthma Step-Care Medications titrated to minimum doses required for control Step up if control not maintained Doses may be outside package labeling Rescue course of systemic steroids may be needed at any step Mild intermittent Asthma (step 1) No daily medication needed Short acting inhaled β 2 -agonists: Albuterol As needed for symptoms If used > 2x a week, need long term control with low-dose inhaled corticosteroid 6

7 Mild Persistent Asthma (step 2) Daily medication for long - term control Low-dose inhaled corticosteroid Budesonide preferred during pregnancy Alternative Rx: cromolyn, leukotriene receptor antagonist, or sustained release theophylline to serum concentration of 5-12 µg/ml Self monitoring with peak flow meter and written action plan Quick relief Short acting inhaled β 2 -agonists (Albuterol preferred) Increasing or daily use indicates need for step-up in long - term control therapy Moderate Persistent Asthma (step 3) Daily medication: two preferred options available 1. Either combination of low-dose inhaled corticosteroid and long acting β 2 -agonists (salmeterol or formoterol) or 2. Medium-dose inhaled corticosteroid Alternative Rx: low or medium-dose inhaled corticosteroid and either theophylline or leukotriene receptor antagonist Quick relief Short acting inhaled β 2 -agonists increasing or daily use indicates need for step-up in long - term control therapy Severe Persistent Asthma (step 4) recommend consultation with asthma specialist Written Action Plan Daily medications for long - term control High-dose inhaled corticosteroid and long acting bronchodilator (salmeterol or formoterol) and, if needed, corticosteroid tablets Alternative Rx: high-dose inhaled corticosteroid and sustained release theophylline Quick relief Short acting inhaled beta 2 agonists increasing or daily use indicates need for stepup in long - term control therapy Green Zone High Yellow Zone Low Yellow Zone Red Zone % of best PEFR 65-80% of best PEFR 50-65% of best PEFR < 50% of best PEFR 7

8 Written Action Plan Green Zone: % of best PEFR asthma is well controlled High Yellow Zone: 65-80% of best PEFR increase inhaled corticosteroid to 4 puffs qid increase inhaled bronchodilator to 2-6 puffs every 1-2 hours till back in green zone call provider if dropping into this zone frequently Written Action Plan (cont...) Low Yellow Zone: 50-65% of best PEFR increase inhaled corticosteroid to 6 puffs qid increase inhaled bronchodilator to 2-6 puffs every 20 min x3, then 2-6 puffs every 2-3 hours for rapid control of symptoms call provider if not improved in hours Written Action Plan (cont...) Red Zone: less than 50% of best PEFR THIS IS AN EMERGENCY! Begin prednisone mg right away Albuterol: 4-6 puffs every minutes up to 3x Call provider If not significantly improved, go to ER or L&D Risk Factors for Fatal Asthma Prior intubation or ICU admission 2 or more asthma hospitalizations in past year 3 or more asthma ER visits in past year Hospital or ER asthma care in past month Current use of systemic corticosteroids History of syncope or seizure due to asthma Serious psychiatric/psychosocial problems 8

9 Emergency Treatment of Pregnant Asthmatic Oxygen: keep O 2 sat > 95% Short acting inhaled beta 2 agonist nebulizor generally favored onset of action less than 5 minutes three doses q 20 min. can be safely given Systemic corticosteroids if no improvement with beta 2 - agonist if exacerbation occurred while on oral steroids Hospitalize Pregnant Asthmatic If FEV 1 remains < 40% predicted If FEV 1 remains 40-70% predicted with: persistent symptoms evidence of pneumonia past history of severe asthma on systemic steroids at time of exacerbation prolonged increase in symptoms prior to visit non-reassuring fetal assessment Discharge Pregnant Asthmatic When there s no or minimal wheezing If FEV 1 remains 60-70% of predicted When on oral and/or inhaled medications 24 hour observation after medicine adjusted shows no deterioration After asthma education provided With follow-up appointment in 3-7 days Asthma Pharmacotherapy Long term control inhaled corticosteroids (Budesonide) long acting β 2 -agonists theophylline (serum 5-12 µg/ml) leukotriene receptor antagonists cromolyn Quick Relief short acting β 2 -agonist (Albuterol) systemic corticosteroids 9

10 Components of Asthma Care Preferred Step Therapy of Asthma During Pregnancy Objective measures for assessment Avoid or control asthma triggers Establish medication plans: step-care Educate asthmatics to become partners in management Category Mild Intermittent Mild Persistent Mod. Persistent Severe Persistent Step Therapy All categories: Inhaled short-acting beta agonist as needed (Albuterol preferred) Low dose inhaled corticosteroid (Budesonide preferred) Medium dose inhaled corticosteroid OR Low dose inhaled corticosteroid plus long-acting beta agonist High dose inhaled corticosteroid plus long-acting beta agonist Prednisone if needed 10