Extra Topic 2.6 -- Pulmonary Edema Flashcards
A 23-year-old pregnant patient at 33 weeks gestation, who is receiving terbutaline for premature labor, presents with respiratory distress. On exam, you hear crackles bilaterally.
What do you think could be the cause of her distress?
(A 23-year-old pregnant patient at 33 weeks gestation, who is receiving terbutaline for premature labor, presents with respiratory distress. On exam, you hear crackles bilaterally.)
The bilateral crackles on exam are suggestive of pulmonary edema,
which could be associated with the use of terbutaline, preeclampsia, pulmonary embolism, or a previously unrecognized cardiac condition.
Although a rare complication, terbutaline use has been associated with pulmonary edema.
Preeclampsia, a condition associated with pregnancy, may result in pulmonary edema secondary to increased vascular permeability.
Pregnancy is associated with hypercoagulability and, often, reduced mobility, predisposing these patients to pulmonary embolism, which can also cause pulmonary edema.
Finally, the physiologic changes of pregnancy result in increased intravascular volume and cardiac output, potentially unmasking or exacerbating a previously unrecognized cardiac condition.
How would you treat pulmonary edema?
Would you intubate this patient?
(A 23-year-old pregnant patient at 33 weeks gestation, who is receiving terbutaline for premature labor, presents with respiratory distress. On exam, you hear crackles bilaterally.)
I would begin by [identify and treating] / [establishing] the underlying cause of the edema.
If I thought the cause was cardiogenic in origin (i.e. myocardial ischemia, cardiomyopathy, or a dysrhythmia), I would consider using diuretics, inotropic agents, beta-blockers, or afterload reducing agents, as indicated.
If I believed her pulmonary edema was non-cardiogenic in origin, I might simply provide diuretic therapy and fluid restriction.
In either case, I would consider providing ventilatory support with PEEP.
While intubation and mechanical ventilation may prove necessary, I would first consider using CPAP.
Xtra Q: Would you intubate the patient?
(make an assumption)
“If her respiratory distress were severe enough, I would consider intubating and applying PEEP.”
How does PEEP help with pulmonary edema?
(A 23-year-old pregnant patient at 33 weeks gestation, who is receiving terbutaline for premature labor, presents with respiratory distress. On exam, you hear crackles bilaterally.)
PEEP improves oxygenation and pulmonary function by redistributing alveolar fluid to areas that are less involved in gas exchange, and by recruiting collapsed alveoli that are contributing to pulmonary shunting.
However, if I were concerned about possible left ventricular dysfunction (i.e. myocardial ischemia or cardiomyopathy), I would apply positive pressure ventilation and PEEP with caution to prevent worsening cardiac function secondary to decreased preload (positive intrathoracic pressure decreases blood return to the heart through the inferior vena cava).
It would also be important to avoid over-inflation of alveoli, which could result in barotrauma, increased capillary permeability, and potentially worsening pulmonary edema.
Doesn’t PEEP just hyperinflate the already open alveoli and risk barotrauma?
(A 23-year-old pregnant patient at 33 weeks gestation, who is receiving terbutaline for premature labor, presents with respiratory distress. On exam, you hear crackles bilaterally.)
While PEEP has the potential to hyperinflate already open alveoli,
the goal is to achieve optimum PEEP where collapsed alveoli are recruited and hyperinflation with subsequent barotrauma is avoided.
