Acute Respiratory Failure and Obstetrics

OVERVIEW

Important causes:

• asthma
• pulmonary oedema (multiple causes)
• infection
• aspiration
• venous air embolism
• amniotic fluid embolism
• pneumomediastinum/ pneumothorax
• influenza

Asthma

• can use B2 agonists and corticosteroids without adverse fetal outcome

APO

• determine cause -> can be from tocolysis with beta-agonists
• NIV, diuresis, O2
• ETT if required
• can be due to tocolytics

ARDS

• low TV and permissive hypercapnia -> fetal acidosis which reduces oxygen binding to fetal Hb -> try and keep PaCO2 < 45, PaO2 > 70mmHg (no human trials on this to confirm this management)
• few case reports using NO
• delivery of fetus doesn’t appear to result in marked improving in respiratory failure

Acid Aspiration

• high risk: decreased gastric emptying, increased gastric acidity and volume, increased abdominal pressure
• bronchoscopy for large pieces
• no role for steroids or BAL
• only use antibiotics in proven infection

Venous Air Embolism

• can occur at any time but more common at caesarian section
• air enters subplacental venous sinuses
• sudden SOB, CP, tachycardia, hypoxia -> cardiac arrest
• mill wheel murmur, ST depression
• FiO2 1.0, left lateral and head down, aspirate CVL if in RV, hyperbaric O2 in those with paradoxical cerebral embolism

Influenza

• pregnant patients were notable for severe presentations during the swine flu outbreak
• expeditious delivery associated with improved
• treat with tamiflu

RESPIRATORY DISTRESS IN LABOUR AND CARDINAL SIGNS

• Peripartum cardiomyopathy: cardiomegaly, S3
• Venous thromboembolism with PE: swollen, painful calf, R heart failure, ECG – S1Q3T3, ST, R strain, CTPA – filling defect
• AFE: Haemodynamic collapse, DIC, seizure, bleeding
• Air embolism: hypotension, cardiac mill wheel murmur
• Pre-eclampsia: HTN, proteinuria
• Tocolytic pulmonary oedema: Tocolytic administration, rapid improvement
• Aspiration pneumonitis: Hx od vomiting or silent aspiration, CXR findings
• Pneumomediastinum: occurs during delivery
• Other causes as in non-pregnant patient