Mechanical Ventilation in Pregnancy
The indications for intubation of a pregnant patient are no different than the non-pregnant patient.
The guiding principle of ventilating the pregnant patient is ensuring adequate oxygen delivery. The goal is a PaO2 of >90 mmHg.
Positive end-expiratory pressure (PEEP) should be applied to keep the FiO2 <60%, but the patient should be kept in the left lateral decubitus position to minimize the effect of PEEP on venous return.
Permissive hypercapnia, a strategy used in acute lung injury, may lead to fetal distress. If higher PaCO2 levels are being sustained in the pregnant patient, then continuous fetal monitoring is required.
Sedation with propofol and opioid drugs are safe, though the fetus may need to be intubated on delivery as these drugs cross the placenta.
Benzodiazepines should be avoided as they have been shown to increase the incidence of cleft palate.
Higher than normal peak and plateau airway pressures can be expected on the ventilator: compression of the diaphragm by the gravid uterus will increase respiratory system elastance.
Fetal viability can be maintained while a patient is on mechanical ventilation, even during maternal brain death. Delivery or termination of pregnancy does not seem to improve the respiratory status of the mother, and therefore is not recommended.