Observatory and Fast Facts

July 21, 2021

Tool helps when to test for bacteria in critically ill pediatric patients

Researchers at Johns Hopkins Medicine have developed a new bedside tool that helps clinicians better determine when to test for bacteria in endotracheal tubes being used for critically ill patients in the pediatric intensive care unit (PICU). The findings were reported in the journal Pediatrics.

To diagnose potentially serious bacterial respiratory infections in a PICU patient receiving invasive mechanical ventilation with an endotracheal tube, physicians and nurses often obtain secretions from inside the tube (known as an endotracheal aspirate) and culture it in the laboratory. The problem with these endotracheal aspirate cultures (EACs) is they may lead to a case of mistaken identity that could do the patient more harm than good, says study lead author Anna Sick-Samuels, MD, MPH, Pediatric Infectious Disease Specialist at Johns Hopkins Children’s Center and Assistant Professor of Pediatrics at the Johns Hopkins University School of Medicine.

“The human respiratory tract is far from a sterile environment, so bacteria cultured from aspirated samples may just be part of the body’s normal microflora and not be causing an infection that needs antibiotics,” says Sick-Samuels. “However, the detection of any bacteria in these cultures is often misinterpreted as a sign of a ventilator-associated infection, which then may result in unnecessary — and potentially harmful — antibiotic treatment.”

To address the problem, Sick-Samuels and her colleagues developed a clinical decision support algorithm for use in the PICU. The algorithm is a simple flow chart of progressively more definitive, “yes or no” criteria by which clinicians can make an informed, rather than speculative, decision about whether an EAC is needed.

For a PICU patient with a tracheostomy (a surgically created airway directly into the trachea) or an endotracheal tube in place for more than 48 hours, Sick-Samuels explains that the algorithm asks clinicians to consider obtaining an EAC only if:

  • The patient has an increased quantity of secretions in the tracheostomy or endotracheal tube over time.
  • There is at least one additional supporting sign of infection, such as fever greater than 38 degrees Celsius (100.4 degrees Fahrenheit), an increase in white blood cell counts, or a chest X-ray that indicates a developing pneumonia.
  • The patient has not had another EAC within the past 3 days.

Surgery before chemotherapy for aggressive ovarian cancer patient

Certain patients have a better chance of a cure through surgical removal of a tumor before chemotherapy, instead of the reverse, a new study shows. Led by researchers at NYU Langone’s Perlmutter Cancer Center and Dana-Farber Cancer Institute, the study used a mathematical tool to examine how doctors should coordinate available treatments for high-grade serous ovarian cancer (HGSC).

Ovarian cancer is the eighth most common cancer and a major cause of cancer death in women worldwide. HGSC constitutes roughly 70 percent of ovarian malignancies and has the worst prognosis. Patients with the condition typically have surgery and chemotherapy, but there has been long-standing controversy over the best order of treatment.

Published online in Proceedings of the National Academy of Sciences, the new analysis argues that patients who can have “complete debulking” surgery first, with chemotherapy added after (termed primary debulking surgery or PDS), should have a superior outcome to the other main treatment option: giving patients a few cycles of chemotherapy to shrink the tumor before surgery (neoadjuvant chemotherapy, or NACT).

“The issue of whether PDS or NACT should be used was highly controversial, and a major reason for it lies in the different characteristics of patients in different clinical studies,” says study first author Shengqing Gu, PhD, Graduate from University of Toronto and now Instructor at Dana-Farber Cancer Institute. “We therefore built a mathematical model to simulate HGSC clinical course, which allows us to compare treatment outcomes in the same virtual patients and examine which group of patients may respond differently to PDS versus NACT.”

The researchers found that in patients who are well enough for surgery, debulking provides better results because it has the best chance of removing cancer cells resistant to chemotherapy. For patients who are too ill for debulking surgery, the study suggests that a shorter period of initial chemotherapy, rather than the currently recommended interval, might provide a greater benefit. The current analyses suggest several questions that future randomized clinical trials should examine. These include how much the influence of the time gap between surgery and subsequent chemotherapy may affect treatment outcome, whether there is a link between the number of initial chemotherapy cycles and outcomes, and whether a complete secondary surgery on relapsed tumor improves prognosis.