The document discusses the physiological changes that occur in the respiratory system during pregnancy. There is an increase in minute ventilation leading to respiratory alkalosis. Functional residual capacity decreases while vital capacity remains unchanged. Shortness of breath is common during pregnancy. Common respiratory conditions complicating pregnancy include asthma, tuberculosis, pneumonia, and influenza. Treatment for these conditions is largely similar to non-pregnant patients with some modifications due to safety.

1. BY
DR.HAFSA

2.  Pulmonary diseases are one of the major indirect
causes of maternal death.
 Significant physiological changes occur in
pregnancy to meet metabolic needs of both
mother and fetus.

3.  Hormonal changes in pregnancy affect the URT &
upper airway mucosa, producing hyperemia,
mucosal edema, hypersecretion & increased
mucosal friability.
 Estrogen is responsible for producing tissue
edema, capillary congestion & hyperplasia of
mucous glands.
 The enlarging uterus & the hormonal effects
produce anatomical changes to the thoracic cage.
 The AP/PA & transverse diameter of the thorax
increases.
 Diaphragm function remains normal.

4.  Anatomical changes to the thorax produce a
decrease in FRC, which is reduced 10-20% by
term.
 The RV can decrease slightly during pregnancy.
 The increased circumference of the thoracic cage
allows VC to remain unchanged & TLC decreases
only minimally by term.
 Hormonal changes do not significantly affect
airway function
 Pregnancy does not change lung compliance.

5.  The MV increases significantly, beginning in the
first trimester & reaching 20-40% above baseline
at term.
 Alveolar ventilation increases by 50-70%.
 The increase in ventilation occurs because of
increased metabolic CO2 production.
 The VT increases by 30-35%.
 The respiratory rate remains relatively constant.

6.  Physiological hyperventilation results in
respiratory alkalosis with compensatory renal
excretion of bicarbonate.
 The arterial CO2 pressure reaches a plasma level
of 28-32 mmHg & bicarbonate is ↓ to 18-21
mmol/L, maintaining arterial pH in the range of
7.40-7.47.
 Mild hypoxemia might occur when the patient is
in supine position.
 Oxygen consumption ↑ at the beginning of the
trimester & ↑ by 20-33% by term because of
fetal demands & maternal metabolic processes.

7. Physiologic dyspnea.
 The increase in minute ventilation that accompanies
pregnancy is often perceived as shortness of breath.
 Shortness of breath at rest or with mild exertion is so
common that it is often referred to as physiologic
dyspnea.
Pathologic dyspnea
 Increased respiratory rate greater than 20 breaths
per minute, arterial PCO2 less than 30 or greater than
35, hypoxemia or abnormal measures on forced
expiratory spirometry, or cardiac echocardiography
 Abrupt or paroxysmal episodes of dyspnea suggest
an abnormal condition

8.  Dyspnea of pregnancy
 Allergic rhinitis
 Bronchial asthma
 Tuberculosis
 Pneumonia
 Influenza
 Anemia
 Interstitial lung disease
 Pleural diseases
 Pulmonary thromboembolism
 Amniotic fluid embolism
 Pneumothorax
 Gestational trophoblastic disease
 Peripartum cardiomyopathy
 Drugs e.g., tocolytics

9.  It is one of the most common conditions
complicating the pregnancy.
 Pregnancy is a heterogeneous immune state
affecting the course of the asthma, during which
the latter may worsen or improve or remain
stable with equal distribution.
 Prevalence of bronchial asthma in pregnancy is
about 8%-12%
 Bronchial asthma is safe during pregnancy if
controlled.

10.  PIH
 Pre eclampia
 Intrauterine growth retardation (IUGR)
 low birth weight
 premature birth
 increased elective caesarian delivery
 Exacerbations during first trimester are
associated with increased risk of congenital
malformations

11.  Diagnosis of bronchial asthma during pregnancy
is similar to that done in non pregnant state,
which includes
 History
 Clinical examination
 pulmonary function tests(PFT).

12.  Management of bronchial asthma during
pregnancy is almost similar to non
pregnant.
 Patient education
 avoidance of triggers
 Goals of bronchial asthma management
include decreasing the use of short acting
beta-2 agonists (SABA), preventing the
exacerbations and maintaining near normal
lung function
 Long acting beta-2 agonists(LABA) are used
in step up therapy only if asthma is not
controlled by medium or low dose inhaled
corticosteroids (ICS).

13.  Systemic corticosteroids are associated with
more adverse effects than inhaled and should be
used only in moderate and severe bronchial
asthma.
 Use of systemic corticosteroids in early
pregnancy is associated with cleft lip, cleft
palate, preeclampsia and gestational diabetes.

14.  Treatment of acute severe asthma in pregnancy
is almost similar to non pregnant counterparts.
 Initially the patients should be treated with
inhaled albuterol or salbutamol 2.5mg for every
20 min followed by systemic corticosteroids.
 Inhaled ipratropium bromide can be added to
this regimen.
 They are monitored for every 30-60 minutes.
Treating maternal hypoxia and continuous fetal
monitoring are more important

15.  Risk factors for tuberculosis (TB) in
pregnancy include positive family
history or past history of TB,
residence in area of high prevalence
of TB.
 Treatment of TB in pregnancy is
similar to that administered to non
pregnant women.
 Streptomycin is contraindicated
because of
and vestibular defects in fetus.
 Breast feeding is not
contraindicated in women taking
anti-TB treatment

16.  Pneumonia is one of the important causes of
indirect maternal mortality
 Most common organisms being
Streptococcus pneumoniae, Haemophilus
influenza, Mycoplasma pneumonia.
 Clinical presentation is similar to that of non-
pregnant woman but risk of respiratory
failure and empyema is increased
 Patient presents with dyspnea. Respiratory
rate is not increased
 Patients with suspected pneumonia should
get a chest radiograph with abdominal
shield.
 Other investigations are sputum microscopy,
sputum culture and serologic tests.
 Quinolones and tetracyclines should be
avoided in pregnancy

17.  It is most common viral infection in pregnancy
 resulting in increased morbidity and mortality.
 Risk of hospitalization for an acute
cardiopulmonary illness is three to four times
more likely in third trimester
 Influenza(H1N1) should be suspected in patients
not responding to routine antibiotics and in
pneumonia or respiratory failure.
 Increased risk of preterm delivery or a low-birth
weight infant, severe pneumonia, maternal
deaths have been observed

18.  It includes prevention and supportive care.
 Antipyretics should be used for the treatment of
fever as these not only reduces fetal tachycardia,
but are also been associated to be a protective
agent against congenital abnormalities.
 Dehydration should be avoided.
 The use of antiviral medications in pregnancy is
controversial.
 Neuraminidase inhibitors(zanamivir, oseltamivir)
are also used in the treatment.