First EDition: Liquid Nicotine Risks, more
Microsensor Perfectly Distinguished Coagulopathy Patients From Controls
AMY KARON
FRONTLINE MEDICAL NEWS
Using less than a drop of blood, a portable microsensor provided a comprehensive coagulation profile in <15 minutes and perfectly distinguished various coagulopathies from normal blood samples—handily beating the results from both activated partial thromboplastin time (aPTT) and prothrombin time (PT).
Dubbed ClotChip, the disposable device detects coagulation factors and platelet activity using dielectric spectroscopy, Evi X. Stavrou, MD, said at the annual meeting of the American Society of Hematology. The development points the way for comprehensive, rapid, point-of-care (POC) assessment of critically ill or severely injured patients and those who need ongoing monitoring to evaluate response to anticoagulant therapy, she added.
Existing POC coagulation assays have several shortcomings, Dr Stavrou, of Case Western Reserve University, Cleveland, said during a press briefing at the conference. They are relatively insensitive, fail to measure platelet activity, or are only approved for specific subgroups of patients, such as those on warfarin, she specified.
To develop an alternative, Dr Stavrou and her associates added a parallel-plate capacitive sensing structure to an inexpensive, disposable microfluidic biochip designed to test 9 microliters (less than one drop) of blood. They built the microsensor from biocompatible and chemically inert materials to minimize the chances of artificial contact activation.
To test the device, the researchers used calcium dichloride to induce coagulation in whole blood samples from 11 controls with normal aPTT and PT values. Time curves of output from the microsensor showed that coagulation consistently peaked within 4.5 to 6 minutes.
Next, the investigators tested blood from 12 patients with coagulopathies, including hemophilia A, hemophilia B, acquired von Willebrand factor defect, and congenital hypodysfibrinogenemia. These samples all yielded abnormal curves, with prolonged times to peak that ranged between 7 and 15 minutes—significantly exceeding those of healthy controls (P = .002).
By plotting rates of true positives against rates of true negatives, the researchers obtained areas under the receiver-operating curves of 100% for ClotChip, 78% for aPTT, and 57% for PT. In other words, ClotChip correctly identified all cases and controls in this small patient cohort, while neither aPTT nor PT did.
Finally, the researchers used the microsensor to measure coagulation activity in normal blood samples that they treated with prostaglandin E2 to inhibit platelet aggregation. Normalized permittivity (an electrical measure) was significantly lower than in untreated control samples (P = .03), but time-to-peak values were the same in both groups. This finding confirms the chip can identify abnormal platelet function, Dr Stavrou said. “ClotChip is sensitive to the complete hemostasis process, exhibits better sensitivity and specificity than conventional coagulation assays, and discriminates between coagulation and platelet defects,” she concluded.
The investigators are recruiting volunteers for an expanded round of testing for the device, and are working to optimize construction to further enhance its sensitivity.
Survey: Overprescribing Is the Cause of the Opioid Crisis
M. ALEXANDER OTTO
FRONTLINE MEDICAL NEWS
Almost a third of doctors blamed overprescribing as the cause of the opioid crisis, according to a survey of 225 US primary care, emergency medicine, and pain management physicians by InCrowd, an online physician survey company.
Respondents said their and other physicians’ overprescribing is the single biggest factor fueling the leap in opioid abuse over the past 5 years.
“We were told…that [opioids] wouldn’t be addictive in the great majority of patients. This was obviously wrong,” said a Utah EP in practice for 38 years. Meanwhile, 24% of the respondents cited aggressive patient drug-seeking as the primary cause, and 18% blamed drug dealers.
In short, the survey pointed out what front-line doctors think needs to be fixed as the nation combats prescription opioid abuse and the subsequent heroin epidemic. Their insights “should be a rallying cry” for changes in 2017, said epidemiologist Diane Hayes, PhD, president and cofounder of InCrowd.
Making pain the “fifth vital sign” and allowing patients to downgrade doctors on surveys if they don’t prescribe or refill opioid prescriptions compounded the situation. Lengthy waits for specialists with better pain options, many of whom are not covered by Medicaid or the Affordable Care Act, also added to the problem, survey respondents said.
“We’re caught in the middle” between the Joint Commission on Accreditation of Healthcare Organization’s fifth vital sign and overprescribing, a primary care physician (PCP) said.
Seventy-three percent of survey respondents said that they want opioid alternatives, noting exasperation with nonsteroidal anti-inflammatory drugs, physical therapy, and exercise. About half recommend behavioral health interventions, while 20% recommend vitamin and herbal supplements. Only 10% recommend medical marijuana, probably because it is inaccessible to most US patients. Meanwhile, the respondents said they want opioid prescribing “hemmed in.” Almost two-thirds wanted refill limits and more frequent refill evaluations, and many agreed that there needs to be a weaning protocol before the drugs are even started. Some wanted to limit advertising.
Easton Jackson, MD, a PCP in West Valley City, Utah, who answered the survey, helped make the answers real by sharing his thoughts.
“We need to recognize that…people don’t set out to get addicted to opioids….We need to educate [patients] and assist them with their expectations. They need to understand that they’re going to have pain from surgery and injuries. Our goal isn’t to make them pain-free. It’s to manage their pain,” he said.
“We as physicians need to write for fewer pills and in lower doses. We need to see our patients back sooner. If it’s not working, stop increasing the dose and instead taper the patient off the medication. We need to be familiar with the adjuvant therapies. As easy as it is to say, ‘send them all to the pain specialist,’ there simply aren’t enough of them around,” Dr Jackson said.
Physician respondents to InCrowd’s opioid survey have practiced an average of 25 years, and were scattered around the United States. They filled out the four-question survey during October 27 to 28, 2016. They signed up to receive and answer InCrowd’s questions, and were paid nominally for their time.
Half (50%) of respondents estimated that they prescribed opioids to <10% of their patients; 38% said they prescribed to less than half of their patients; and 12% estimated they prescribed opioids to more than half of their patients.
