Clinical Pulmonary Medicine
Pulmonary embolism in pregnancy: A diagnostic conundrum
Pulmonary embolism (PE) is the 6th leading cause of maternal mortality in the United States. The clinical signs and symptoms of PE are usually nonspecific and often overlap with the normal physiologic changes of pregnancy. Due to low specificity and sensitivity of D-dimer test, pregnant patients with suspected PE often undergo CT pulmonary angiography (CTPA) and ventilation-perfusion scanning, both of which can cause radiation exposure to mother and fetus.
To answer whether pregnancy-adapted YEARS algorithm (Van der Hulle T et al. Lancet. 2017;390:289) can be safely used to avoid diagnostic imaging, Artemis Study Investigators prospectively studied three criteria from YEARS algorithm in combination with a D-dimer level (Van der Pol et al. N Engl J Med. 2019;380:1139. The three criteria included clinical signs of deep-vein thrombosis (DVT), hemoptysis, and PE as the most likely diagnosis. PE was considered ruled out when none of the three criteria were present and D-dimer was less than 1000 ng/mL or if one or more of the criteria were met and D-dimer was less than 500 ng/mL. Patients in whom D-dimer was greater than 1000 ng/mL or in those with D-dimer greater than 500 ng/mL and had 1 or more of the YEARS algorithm criteria present, PE could not be ruled out and underwent CTPA. A modification of the criteria was done only for patients who had clinical signs of DVT at baseline. These patients underwent compression ultrasonography and if a clot was found, CTPA was not performed and patients were started on anticoagulation therapy. Those with negative DVT studies were subclassified based on D-dimer levels as the study population above. Patients in whom pulmonary embolism was not ruled out underwent CTPA. Of these 299 patients, 16 (5.4%) were confirmed to have PE at baseline.
In the remaining 195 patients in whom PE was ruled out on the basis of study protocol, a 3-month follow-up diagnosed one patient (0.51%) with VTE. Using pregnancy-adapted YEARS algorithm, CTPA was avoided in 39% of the patients of which 65% were in their first trimester when the radiation exposure can be most harmful to the fetus.
Muhammad Adrish, MD, FCCP
Steering Committee Member
Munish Luthra, MD, FCCP
Steering Committee Member
Cardiovascular Medicine and Surgery
Physical examination of low cardiac output in the ICU
Rapid evaluation of shock requires identifying signs of tissue hypoperfusion and differentiating between cardiogenic, obstructive, hypovolemic, and vasodilatory etiologies. Cardiac abnormalities may also contribute to mixed shock states in a broad array of critically ill patients. Left ventricular dysfunction in inpatients correlates with physical exam, with a 2.0 positive likelihood ratio and 0.41 negative likelihood ratio (Simel DL, Rennie D, eds. The Rational Clinical Examination: Evidence-Based Clinical Diagnosis. 2009). Accurate clinical assessment of cardiac output, however, is a fraught endeavor. In a recently published large series of patients with unplanned ICU admission, atrial fibrillation, systolic blood pressure (BP) < 90, altered consciousness, capillary refill time >4.5 seconds at the sternum, or skin mottling over the knee predicted low cardiac output with specificity >90%. Of 280 patients with a cardiac index of < 2.2 L/min/m2, less than half had any one of these findings (Hiemstra, et al. Intensive Care Med. 2019;45:190).