PULMONARY DISEASES (AB) Flashcards
Which hormone is responsible for pulmonary changes during pregnancy, especially in the first trimester?
Progesterone
What happens to vital capacity during pregnancy?
It increases by approximately 20% by late pregnancy.
What is vital capacity?
The total amount of exhaled air after a forced expiration.
What happens to expiratory reserve volume during pregnancy?
It decreases from 1300 mL to approximately 1100 mL.
Why does tidal volume increase by approximately 40% during pregnancy?
Due to respiratory stimulation by progesterone.
Why is lung compliance reduced in pregnancy?
Because the enlarged uterus pushes the diaphragm, reducing lung expansion.
How much does minute ventilation increase during pregnancy?
By 30 to 40% due to increased tidal volume.
What happens to arterial PO2 during pregnancy?
It increases from 100 to 105 mmHg.
Why does arterial PCO2 decrease from 40 to 32 mmHg in pregnancy?
Due to increased metabolic demands and hyperventilation.
What happens to residual volume in pregnancy?
It decreases by approximately 20% from 1500 mL to 1200 mL.
Why is chest wall compliance reduced during pregnancy?
Due to the expanding uterus and increased intra-abdominal pressure.
What pulmonary function change begins at 14-16 weeks AOG?
Forced vital capacity and peak expiratory flow progressively increase.
What is total lung capacity (TLC)?
The entirety of gas in the lungs at any given time.
What are the components of total lung capacity?
Vital capacity (VC) and residual volume (RV).
What is tidal volume (TV)?
The volume of air that goes in and out of the lungs in a normal, relaxed breathing.
What is inspiratory reserve volume (IRV)?
The amount of air inhaled beyond the tidal volume.
What is expiratory reserve volume (ERV)?
The amount of air exhaled beyond the tidal volume.
What is residual volume (RV)?
The air that remains in the alveoli after a forceful expiration.
What lung capacities cannot be measured directly?
Those that involve residual volume (RV), such as functional residual capacity (FRC) and total lung capacity (TLC).
What are common risk factors for asthma exacerbations in pregnancy?
Respiratory viral infections, discontinuation of treatment, smoking, psychological stress, GERD, allergic rhinitis.
How does pregnancy affect asthma severity?
1/3 of cases improve, 1/3 remain the same, 1/3 worsen.
What weeks of gestation are asthma exacerbations most common?
Between 17-34 weeks (mean 25 weeks).
What are the potential maternal complications of asthma in pregnancy?
Maternal hypoxia, preeclampsia, preterm labor, low birth weight, need for cesarean delivery.
What are the fetal effects of maternal asthma?
Oligohydramnios, low birth weight, premature delivery, fetal demise, meconium staining.