By William K. Alcorn
The use of non- invasive cardiac output technology to complement blood pressure monitoring will revolutionize the care of critically injured patients in the hospital at all levels, said a trauma surgeon at St. Elizabeth Health Center who headed a study on the issue.
The study validated the use of Cheetah Medical’s NICOM Bioreactance Technology noninvasive cardiac output technology in Level I trauma surgery, said Dr. C. Michael Dunham, who led the project. The findings of the study, the first to validate the noninvasive technology in a trauma setting, were published in August in the Journal of Trauma and Acute Care Surgery.
The study, conducted at the St. Elizabeth Level I Trauma Center in 2011, also found that the noninvasive cardiac output technology more quickly gives doctors a better idea of what is causing low blood pressure, thus enabling the physicians to diagnose and treat the patient more quickly and accurately, Dr. Dunham said.
The bottom-line effect is that the most seriously injured trauma patients stayed in the hospital an average of three fewer days compared with when only blood-pressure monitoring is used, said Dr. Dunham, assistant director of trauma and critical care services at SEHC.
A Niles resident, Dr. Dunham received his bachelor and medical degrees at the University of Tennessee. His general surgery residency was at the University of Tennessee Medical Center and his fellowship in trauma surgery and critical care at the Maryland Institute for Emergency Medical Services Systems, also known as the Baltimore Shock Trauma Center, where he worked for 14 years.
Cheetah Medical’s system has four sensor pads, each containing an outer transmitting sensor and an inner one for receiving signals from the patient’s body, which are applied around the heart on the chest and/or back, much like an electrocardiogram.
The sensor pads relay signals to a device that continuously monitors the movement of blood in the veins, arteries and heart chambers.
Previous studies have proven the value of monitoring cardiac output in trauma patients to predict and diagnose patient conditions. However, most methods are invasive and are accurate only in limited, controlled situations.
Invasive blood pressure and heart-output monitoring involve physically inserting a catheter — a tube — into an artery, vein or a heart chamber. A catheter is more time consuming to set up than the Cheetah NICOM, which is noninvasive and painless and has no risk of infection, as there is with any surgery, Dr. Dunham said.
The Cheetah NICOM Bioreactance Technology, which has been around for about five years and used in surgery and the intensive-care unit but not in a trauma center, has made it possible to monitor cardiac output more quickly with a noninvasive procedure.
The study by Dr. Dunham and his team is the first to comprehensively examine the use of NICOM technology in trauma patients. The St. Elizabeth trauma team began using NICOM routinely in severely injured trauma patients in fall 2010.
For purposes of the study, approved by the hospital’s Institutional Review Board, NICOM was used in 270 consecutive trauma patients from late in March and all of April and May 2011.
“Historically, cardiac output monitoring was reserved for the intensive-care unit. We moved it to the emergency department, which is the earliest-care phase in the hospital for trauma patients,” Dr. Dunham said.
Investigators found that NICOM measurements better predicted complications such as major blood loss and mortality, than blood pressure alone; and that cardiac output helped doctors identify the difference between patients with and without blood loss.
In 90 percent of all patients, it took an average of only eight minutes after arrival at the emergency department for cardiac output to be obtained. Set-up with NICOM is about 5 minutes compared to the labor-intensive use of a catheter, which takes 20 minutes to 60 minutes to prepare, Dr. Dunham said.
Also, the team compared records of the 270 patients in the test to trauma patients from the same time periods in previous years and found that for the 95 percent of patients in the most common trauma severity categories, the average length of hospital stay was three days shorter for NICOM patients.
“In trauma, we need to quickly diagnose complex injuries and rapidly make treatment decisions,” said Dr. Dunham.
“With little time to prepare and investigate, we constantly look for more information about the patient,” Dr. Dunham added. “The results of our study show that hemodynamic [blood circulation] monitoring with the Cheetah NICOM system gives us significantly more information than traditional monitoring methods within minutes of the patient’s arrival that we normally had access to only in intensive care settings.
“This strategy empowers the trauma team with valuable information that speeds therapeutic decisions and, in our experience, leads to improved outcomes and reduced length of hospital stay compared to using traditional measures such as blood pressure.
“The results from this study imply that trauma programs should seriously consider incorporating noninvasive hemodynamic and cardiac output monitoring,” Dr. Dunham said.