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HMSW Researchers Investigate Respiratory Problems in High-Risk, Obese Patients

FORT WORTH, Texas — Researchers at  Harris Methodist Southwest Hospital, in conjunction with  researchers at Presbyterian Hospital of Dallas, say a special type of sensor may better warn of potentially deadly breathing problems and sleep apnea in high-risk, obese patients after surgery. Their findings are published in the February edition of the American Journal of Nursing.

A pulse oximeter, which attaches to the finger, has been the sensor typically used by hospitals to monitor patient oxygen levels. But the new study, led by nurse researcher Les Rodriguez, M.P.H., R.N., a clinical education specialist at Harris Methodist Southwest Hospital, shows that an advanced breathing system, called capnography, better monitors patients’ breathing, warns of potentially deadly sleep apnea and at the same time delivers oxygen through a nose piece.

“Some people who are sedated and given pain medications for surgery have trouble breathing on their own after the procedure. This is especially true for obese patients, who also have a higher rate of sleep apnea,” Rodriguez said. “This is an important area of research as treating obese patients with sleep apnea becomes more and more common.”

Clinicians have long known that these high-risk patients are at more risk for breathing problems when receiving pain medications after surgery. But doctors and nurses weren’t always sure the best way to monitor them, according to the new research.

Based on the findings, Presbyterian Hospital of Dallas now has 25 of the capnography machines available for high-risk patients.

“This study’s findings suggest that capnography may help identify early changes in respiratory function better than pulse oximetry and respiratory rate assessment by observation, which are the current standard means of assessing patients’ breathing,” Rodriguez said.

Rodriguez co-authored the paper with Rob Hutchison, PharmD, pain management and palliative care specialist at Presbyterian Hospital of Dallas.

Sleep apnea, in which the upper airway can become partly or completely occluded during sleep, places hospitalized patients at higher risk for respiratory complications because the drugs used to sedate patients for surgery can relax the pharynx and increase the chances of airway obstruction. Sometimes fatal heart and respiratory problems can result from sleep apnea.

“While more research is needed to determine the role of electronic monitoring in preventing respiratory depression in these types off patient, capnography may become a preferred tool for safe pain management in patients after surgery,” Hutchison said. 

The research looked at 54 postoperative patients who had orthopedic surgery and were receiving pain medications and at risk for sleep apnea. The results found that respiratory problems were detected at a significantly higher rate in the capnography group.  In total, 146 episodes of respiratory depression were detected during the 36 hours on the general care nursing unit: 140 in the capnography group and six in the control group.

Pauses in breathing while sleeping, an indicator of sleep apnea risk, were detected in the capnography group at twice the rate as in the control group.

“We discovered that this monitoring breathing system not only provides breathing assistance and monitors oxygen levels in the patient, it also warns of the their sleep apnea problems,” Rodriguez said. “We think that’s a significant finding that could help clinicians better treat these high-risk patients.”

About Harris Methodist Southwest Hospital
Harris Methodist Southwest Hospital is affiliated with Texas Health Resources and has served the residents of southwest Tarrant County since 1987. A full-service hospital built with its patients in mind, Harris Methodist Southwest offers comprehensive health care services. The personal approach to health care includes 24-hour emergency services, women’s services, inpatient and outpatient services, rehabilitation services, diagnostic services and a variety of education classes.

About Texas Health Resources
Texas Health Resources is one of the largest faith-based, nonprofit health care delivery systems in the United States and the largest in North Texas in terms of patients served.  THR controls 13 affiliated hospitals and a medical research organization, and is a corporate member or partner in seven additional hospitals and surgery centers.  THR’s family of hospitals includes Harris Methodist Hospitals, Arlington Memorial Hospital and Presbyterian Healthcare System.  For more information about Texas Health Resources, visit

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