Treatment depends on disease severity. No therapeutic regimen for management of pregnant asthmatics is universally accepted (Bain, 2014). 3-Agonists help abate bronchospasm, and corticosteroids treat inflammation. Regimens recommended for outpatient management are listed in Figure 51-2. For mild asthma, inhaled 3-agonists as needed are usually suicient. For persistent asthma, inhaled corticosteroids are administered every 3 to 4 hours. The goal is to reduce the use of 3-agonists for symptomatic relie. A case-control study from Canada with a cohort of more than 15,600 nonpregnant women with asthma showed that inhaled corticosteroids reduced hospitalizations by 80 percent (Blais, 1998). At Parkland Hospital, Wendel and
FIGURE 51-2 Stepwise approach to asthma treatment.oICS = inhaled corticosteroids; LABA = long-acting 3-agonists; OCS = oral coticosteroids. (Modified from Barnes PJ: Asthma. In Kasper D, Fauci A, Hauser SL, et al (eds): Harrison's Principles of Internal Medicine, 19th ed. New York, McGraw-Hili Education, 2015, p 1669.) sions for severe exacerbations with inhaled steroids.
corticosteroids became available. Minimal beneit is gained with use of these compounds and they have a high rate of side efects. However, some theophylline derivatives are considered useful for oral maintenance therapy if the initial response to inhaled corticosteroids and 3-agonists is not optimal (Dom browski, 2004b).
zileuto n, zairlukast, and montelukast. hese drugs are given orally or by inhalation for prevention, but they are not efec tive for acute disease (Barnes, 2015). For maintenance, they are used in conjunction with inhaled corticosteroids to allow minimal dosing. Approximately half of asthmatics will improve with these drugs. hese agents are not as efective as inhaled corticosteroids, and there is little experience with their use in pregnancy (Fanta, 2009).
mast cell degranulation. They are inefective for acute asthma and are used primarily to treat childhood asthma.
• Management of Acute Asthma
Treatment of acute asthma during pregnancy is similar to that for the nonpregnant asthmatic. Importantly, the threshold for hospitalization is signiicantly lower. Intravenous (IV) hydration may help clear pulmonary secretions, and supplemental oxygen is given by mask. The therapeutic aim is to maintain the P02 >60 mm Hg, and preferably normal, along with 90to 95-percent oxygen saturation. Baseline pulmonary function testing includes FEV) or PEFR. Continuous pulse oximetry and electronic fetal monitoring, depending on gestational age, may provide useful information. Antibiotics are not given unless there is concomitant pneumonitis, which is caused by the same organisms discussed on page 992 (T erraneo, 2014).
First-line therapy for acute asthma includes a short-acting 3-adrenergic agonist, such as terbutaline, albuterol, isoetharine, epinephrine, isoproterenol, or metaproterenol, which is given subcutaneously, taken orally, or inhaled. In severely ill women, these drugs can be given IV (Barnes, 2015). They bind to speciic cell-surface receptors and activate adenylyl cyclase to increase intracellular cyclic AMP and modulate bronchial smooth muscle relaxation. Long-acting preparations are used for outpatient therapy.