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Syncope and PE, manikins and CPR training

1 in 6 patients admitted for syncope may have PE

Nearly one in six patients hospitalized for a first episode of syncope were found to have a pulmonary embolism (PE), and the rate of PE was highest among those who did not have an alternative explanation for syncope, a study found.

Researchers in Italy performed a systematic workup for PE in 560 patients who visited the emergency department for a first episode of syncope and were admitted to one of 11 hospitals, regardless of whether there were alternative explanations for the syncope. PE was ruled out in patients who had a low pretest clinical probability, defined by the Wells score and a negative D-dimer assay. In all other patients, CT pulmonary angiography or ventilation-perfusion lung scanning was done.

Results appeared in the Oct. 20, 2016, New England Journal of Medicine.

In 330 of the 560 patients (58.9%), PE was ruled out on the basis of the combination of low pretest clinical probability and a negative D-dimer assay. Of the remaining 230 patients, 135 (58.7%) had a positive D-dimer assay only, three (1.3%) had a high pretest clinical probability of PE only, and 92 (40.0%) had both. PE was diagnosed in 72 of the 180 patients (40.0%) who underwent CT angiography and in 24 of the 49 patients (49.0%) who underwent ventilation-perfusion scanning. PE was also the cause of death of one patient in whom an autopsy was performed. In total, PE was confirmed in 97 patients who had a positive D-dimer assay, a high pretest clinical probability, or both (42.2%; 95% CI, 35.8% to 48.6%). In the entire cohort, the prevalence of PE was 17.3% (95% CI, 14.2% to 20.5%).

PE was detected in 52 of the 205 patients who had syncope of undetermined origin (25.4%; 95% CI, 19.4% to 31.3%) and in 45 of the 355 patients who were regarded as having a potential alternative explanation for syncope (12.7%; 95% CI, 9.2% to 16.1%). Of the latter 45 patients, 31 (68.9%) had a lobar or more proximal location of the thrombus on CT or a perfusion defect of more than 25% of the area of both lungs on ventilation-perfusion scanning.

Tachypnea was more prevalent among the patients with PE than among the patients without (45.4% vs. 7.1% of the patients), as was tachycardia (33.0% vs. 16.2%), hypotension (36.1% vs. 22.9%), clinical signs or symptoms of deep venous thrombosis (40.2% vs. 4.5%), previous venous thromboembolism (11.3% vs. 4.3%), and active cancer (19.6% vs. 9.9%). Of the 97 patients with PE, 24 (24.7%) had no clinical manifestations of the diagnosis, including tachypnea, tachycardia, hypotension, or clinical signs or symptoms of deep venous thrombosis.

“Although the prevalence of pulmonary embolism was highest among patients who presented with syncope of undetermined origin (25% of patients), almost 13% of patients with potential alternative explanations for syncope had pulmonary embolism,” the researchers wrote. “Not surprisingly, patients with dyspnea, tachycardia, hypotension, or clinical signs or symptoms of deep-vein thrombosis were more likely to have pulmonary embolism, as were those with active cancer. However, the proportion of patients who did not have these features yet had an objective confirmation of pulmonary embolism was not negligible.”

Manikins may improve CPR training

Video-only training in cardiopulmonary resuscitation (CPR) for patients' families resulted in a noninferior difference in chest compression rate but less compression depth compared to training with a video and manikin, a trial found.

Researchers performed a prospective, cluster randomized trial of CPR education for family members of inpatients with high-risk cardiac conditions. Eight hospitals were randomized to offer either video-only or video-manikin training before discharge with volunteer trainers. From February 2012 to May 2015, 1,464 subjects were enrolled and 522 subjects completed a skills assessment six months after training.

Mean chest compression rate among those trained with video-only compared with those trained with video-manikin was assessed, with a noninferiority margin of eight chest compressions per minute. Mean differences in chest compression depth were assessed as a secondary outcome. Results were published online on Oct. 4, 2016, by Circulation: Cardiovascular Quality and Outcomes and appeared in the November 2016 issue.

The mean chest compression rates were 87.7 chest compressions per minute in the video-only group and 89.3 chest compressions per minute in the video-manikin group. The researchers concluded that video-only training met the standard for noninferiority, at a mean difference of −1.6 compressions per minute (90% CI, −5.2 to 2.1). The mean chest compression depth was 40.2 mm in the video-only group and 45.8 mm in the video-manikin group, a mean difference of −5.6 mm (95% CI, −7.6 to −3.7).

The researchers said the findings suggest a potential tradeoff in efforts to teach basic CPR skills. Video-only training may offer broader dissemination potential at low cost with noninferior chest compression rate, while manikin-based instruction may result in somewhat better CPR skill performance at higher cost (and possibly less dissemination).

“If appropriate practical questions are further addressed, offering VO [video-only] CPR training to families before hospital discharge could become a routine patient and family-centered health educational opportunity in >4,000 acute care hospitals that care for patients with cardiac disease in the United States,” the authors wrote. “If implemented broadly, CPR education could be well matched to a large population at high risk of subsequent cardiac arrest, establishing an opportunity to make important gains in survival from cardiac arrest. Furthermore, being able to train individuals with VO may allow for broader, more scalable dissemination of CPR training to the lay public; however, shallower CC [chest compression] depth at 6 months suggests that additional work to optimize VO strategies may be required.”