By Renee DiIulio

Point-of-care testing (POCT) has been embraced by a medical community that equates new technology with better patient care. Providers of medical care are under pressure to provide care more quickly than in the past, and many see POCT as a solution to remove patient bottlenecks. However, James H. Nichols, PhD, DABCC, FACB, said there is a proliferation of misinformation about POCT. Nichols, associate professor of pathology at Tufts University School of Medicine in Boston and director of clinical chemistry at Baystate Health System in Springfield, Mass, gave the keynote address, “Finding Value at the Bedside: Evidence-Based Practice for POCT,” at the 20th International Symposium on Critical Care and Point-of-Care Testing in Wurzburg, Germany. “Faster is often understood to mean better outcomes without the research to back this conclusion,” he said.

James H. Nichols, PhD, DABCC, FACB

Evidence-Based Medicine
Evidence-based medicine (EBM) represents a new age in health care. Nichols traced medicine’s development through the ages, from its dawn with humors, astrology, and bloodletting, through its dark period characterized by belief-based treatments, into an enlightenment with the discovery of the pathologic basis of disease, and followed by subsequent growth with advances in prevention, diagnosis, and treatment.

Now, as patient knowledge, costs, and resource shortages increase, so has the need for fact-based medical decisions. Doctors find themselves facing greater lawsuit risks, questions about alternative therapies, higher pressure for faster turnaround, and an increasing amount of available information with less time to sort through it all—thus the age of EBM.

Nichols said the Centre for Evidence-Based Medicine in Toronto defines EBM as “the integration of best research evidence with clinical expertise and patient values.” Nichols elaborated on the pieces of this definition, noting that the “best research evidence” includes clinically relevant research from the basic sciences as well as “patient-centered research into accuracy and precision diagnostic tests, the power of prognostic markers, and the efficacy/safety of therapeutic, rehabilitative, and preventive regimens.” Clinical expertise combines the “ability to use clinical skills and past experience” with the identification of a “patient’s unique health state, diagnosis, risks, and benefits of interventions,” in addition to their personal values and expectations. And finally, patient values encompass a “patient’s unique preferences, concerns, and expectations,” which must be integrated into clinical decisions.

Research cited by Nichols1 estimates that only 20% to 25% of medical decisions are evidence based.

Low Use Belies Large Need
One possible reason for the low use of EBM is that physicians do not have the time to review the best research evidence on their own. In relation to POCT, “each lab must research new test requests to determine clinical utility, cost effectiveness, and management and reimbursement issues,” said Nichols.

According to Nichols, EBM offers fact-based support for medical decision-making, reducing subjectivity and practice variability. “Clinicians, staff, and laboratorians need guidance to apply POCT in the most effective manner for patient benefit. This guidance should be based on a concurrence of the scientific evidence to date,” he said.

POCT Recommendation Language

• A — Strongly recommend POCT (Good evidence POCT improves important clinical outcomes, benefit outweighs risk)
• B — Recommend POCT (Fair evidence support)
• C — No recommendation (Fair outcomes, but balance of benefit and harm too close to justify)
• D — Recommend against POCT (Fair evidence against)
• I — Insufficient evidence to recommend for or against POCT

Guidelines Drive Evolution
The need for evidence-based practice is the motivation for the National Academy of Clinical Biochemistry’s Laboratory Medicine Practice Guidelines (LPMGs). In 2002, the organization, whose mission includes the development of LPMGs for the application of clinical biochemistry to medical diagnosis and therapy, began its development of guidelines for POCT. As chair of the Evidence-Based Practice for POCT Organizing Committee and its pH focus group, Nichols was able to share the organization’s process and progress.

The committee first formed 13 focus groups on specific topics. The groups included clinicians, laboratorians, industry professionals, and representatives of professional societies.

In spring 2003, the groups developed specific and appropriate clinical questions. They include:

  • What is the effect on outcome when comparing POCT to core lab testing for screening patients for disease X in the emergency room?
  • Does POCT for disease X improve outcome in patients compared to core lab testing?

Nichols provided the systematic review for the formation of the questions. The key components are:

  • How: clinical application (screening, diagnosis, management)
  • What: comparison being measured (core versus POCT)
  • Where: patient population or clinical setting (ED, home, clinic)
  • Why: outcome (clinical, operational, economical)

During the summer and winter of 2003, the groups conducted systematic reviews of the literature, which were limited to peer-reviewed articles in English with abstracts using human subjects. Once a study was determined to be eligible, it was graded based on its design, internal and external validity, literature synthesis, and link to the outcome. Five recommendation levels were used once the research had been reviewed (see sidebar).

The draft recommendations were published online this spring. The committee will publicize its findings this summer. In the fall, revisions will be made based on feedback with publication of the final recommendations expected in spring 2005.

LPMG Findings on pH
In keeping with the development plan, Nichols shared his findings on pH. Three questions were asked:

  1. Does the use of pH paper for assisting the placement of nasogastric tubes, compared to clinical judgment (air and pressure) improve the placement of tubes on inpatient, endoscopy, home care, and nursing home patients?
  2. Does continuous gastric pH monitoring, compared to random gastric pH determinations, improve patient symptoms and severity in the management of achlorhydria and gastric reflux in inpatient and endoscopy patients?
  3. Is one brand of pH paper better than another in improving patient symptoms and time to treatment of chemical burns in emergency and urgent care patients, and in improving the accuracy of nasogastric tube placement in inpatient, endoscopy, home care, and nursing home patients?

In answer to these questions, LPMG offered the following recommendations:

  1. The use of pH testing to assist in the placement of nasogastric tubes is recommended. The choice of measuring pH with an intragastric electrode or testing tube aspirates with a pH meter or pH paper will depend on consideration of the clinical limitations of each method, and there is conflicting evidence over which method is better (Class II—prospective comparative trials and expert opinion).
  2. The intermittent use of pH paper on gastric aspirates in the diagnosis of gastric reflux disease in favor of continuous monitoring is not recommended. The role of pH testing to manage acid suppression therapy is controversial. Although the use of pH testing is common on critical care units, there is a lack of evidence that pH monitoring to adjust drug dosage improves either morbidity or mortality in these patients (Class II—well-designed case controlled and correlation trials and consensus opinion).
  3. LPMG does not recommend one brand of pH paper over another for use in the treatment of chemical burns or placement of nasogastric tubes (Grade III—case reports and opinion).

Survival of the Fittest
These recommendations, like the other POCT guidelines, will be useful for three reasons, according to Nichols:

  1. To sort the facts from conjecture when implementing and utilizing POCT devices.
  2. To establish proven applications from off-label and alternative uses of POCT.
  3. To define the mechanisms and strategies for optimizing patient outcome.

In essence, they will assist doctors in applying EBM and moving medicine along into its next age.

Renee Dilulio is a contributing writer for Clinical Lab Products.

Reference
1. Booth A. What proportion of healthcare is evidence based? [resource guide]. Available at http://www.shef.ac.uk/scharr/ir/percent.html. Accessed July 19, 2004.