Asthma

Question 1

How does pregnancy affect the respiratory system?

Answer 1

Compensated respiratory alkalosis, incr in O2 demand, decreased FRC and TLC, respiratory rate remains unchanged
Ddx: FEV1

Question 2

What is mild intermittent asthma?

Answer 2

FEV1>80%, well-controlled, less than 2 episodes/week. Use SABA like albuterol

Question 3

What is mild persistent asthma?

Answer 3

> 2 episodes/week but NOT daily. FEV1>80%, use low dose steroids: pulmicort (budesonide), flovent (fluticasone) and prn albuterol

Question 4

What is moderate persistent asthma?

Answer 4

daily sx, nocturnal sx>1/week. Limitations in nl activity. 60-80%. Medium low dose steroids (incr puffs, use 3-6 puffs), LABA (salmeterol)

Question 5

What is severe persistent asthma?

Answer 5

continuous sx. Limits activity. Peak <65%. High dose steroids (solumedrol) and oral steroids.

Question 6

When would you discharge patient home after asthma exacerbation?

Answer 6

If peak expiratory flow >70%, 60 min after last tx w/ no distress

Question 7

What are indications for ICU admission and intubation?

Answer 7

• signs of respiratory distress
• Inability to maintain O2>92% despite HFNC, PO2<60, PCO2>45, pH<7.35, RR >30-40, maternal exhaustion, AMS.
• If recently received oral steroids, need IV hydrocortisone q8 to avoid adrenal crisis.

Question 8

How do you counsel on asthma in pregnancy?

Answer 8

Depends on asthma severity. Mild=good outcomes. severe/poorly controlled: incr prematurity, need for CS, FGR, maternal morbidity.

Question 9

What are effects of pregnancy on asthma?

Answer 9

Mild asthma: exacerbation of 12%, hospitalization 2%
Moderate asthma: exacerbation 25% and hospitalization 7%
Severe asthma: 51% and hospitalization 26%
Symptoms variable during pregnancy, can improve or stay the same

suboptimal control associated with incr maternal/fetal risk. Incr risk low birth weight and prematurity.

Question 10

How do you diagnose asthma?

Answer 10

Sx: wheezing, chest cough, SOB, triggers (allergens, exercise, infections), wheezing on auscultation supports diagnosis.

Formal ddx: spirometry demonstrating airway obstruction that is partially reversible (>12% incr in FEV1 after bronchodilator). If clinically seems like asthma but can’t demonstrate reversible airway obstruction, can do trial of asthma therapy. If positive response, it’s asthma.

Question 11

Differential diagnosis of respiratory sx during pregnancy?

Answer 11

Dyspnea of pregnancy, GERD, chronic cough from postnatal drip, bronchitis.
Dyspnea of pregnancy vs. asthma: DOP has lack of cough, wheezing, airway obstruction

Question 12

How to assess pts with asthma during pregnancy?

Answer 12

Routine eval of pulmonary function. Spirometry preferable. Worsening sx evaluated w/ peak flow measurements. Identify prior hospitizatlions, iCU admissions, intubations, oral corticsteroid requirements. And effect of prior pregnancy on asthma control.

Question 13

What is rescue therapy for asthma during pregnancy?

Answer 13

albuterol=1st choice. Short acting B2 agonist.
- mechanism of action: bronchial smooth muscle relaxation and inhibiting immediate hypersensitivity mediator release, particularly from mast cells
- Up to 2 treatments at 20 min interval. Counsel on use: when have exacerbation of sx (cough, chest tightness, dyspnea, wheezing).

Question 14

What is add-on controller therapy? When is it added?

Answer 14

LABA (long-acting B2 agonist): when not controlled with use of medium-dose inhaled corticosteroids. Salmeterol and Formoterol.

Question 15

How do you manage asthma?

Answer 15

Mild intermittent: albuterol as needed
Mild persistent: albuterol prn + ICS (Preferred ICS=budesonide. alternative is cromolyn, leukotriene-R antagonist or theophylline- bronchodilator)
Mod persistent: ICS + LABA (Salmeterol or Formeterol)
Severe persistent: high-dose ICS + LABA (salmeterol) + oral corticosteroid. Alternative: high dose iCS + theophylline + oral corticosteroid.

Question 16

What are nonpharmacologic approaches for asthma?

Answer 16

Avoid allergens, irritants (smoking). If GERD, smaller meals, elevate head of bed. Reduce mold, dust mites, environmental triggers. Educate about asthma, skills for self-monitoring, correct use of asthma, plans for long-term management, how to manage worsening asthma.

Question 17

How do you assess acute asthma?

Answer 17

H&P, pulse ox. FEV1 <70% sustained for 1hr, no distress and reassuring fetal status can be discharged
Incomplete response (FEV1 50-70%, individualize dispo.

Question 18

What should discharge regimen be after acute asthma episode?

Answer 18

SABA 2-4 puffs q3-4. Oral corticosteroids (Prednisone 40-60 daily for 3-10d). Outpatient follow up within 5 days.

Question 19

What is fetal surveillance for asthma?

Answer 19

Considere US/APT if moderate or severe. IF poorly controlled or mod-to severe, serial US for fetal growth at 32w

Question 20

How do you counsel asthma patients about labor?

Answer 20

Continue asthma medications. Adequate anesgelsia to decor risk of bronchospasm. If systemic corticosteroids , need stress dose steroids (hydrocortisone 100mg q8 and 24hr pp), delivery may benefit respiratory status if has mature fetus.

Hemabate/Carboprost is a prostaglandin analogue which causes smooth muscle contraction and can precipitate bronchospasm. Indomethacin can also do that.

Question 21

What is acute management of asthma?

Answer 21

• continuous O2 monitoring and vitals (SpO2>95%)
• continuous fetal monitoring
• Oxygen by facemark
• Albuterol 5mg q20min for 3 doses
• if inadequate response, use ipatroium bromide
• if poor response, systemic (oral or IV) steroids.

-f FEV1<50%, impending respiratory arrest:
- iCU admission and intubation

Question 22

What are risks of systemic steroid use in pregnancy?

Answer 22

Maternal:
- inc risk PTD and PEC

Fetal:
- incr risk cleft lip/palate if 1st trimester
- LBW