A catheter-based ultrasound technique can measure heart function in children undergoing surgery with similar effectiveness as the more traditional method of inserting a probe around the patient's aorta, according to a study published online March 18 in Anesthesiology.
Cardiac output is a key vital sign monitored in surgical patients, but tracking it via physical examination of critically ill children can be inexact, particularly since the methods used are adapted from adult patients, wrote a team led by Dr. Theodor Sigurdsson of the University Hospital of Lund in Sweden. Using ultrasound for this purpose shows promise.
"The hypothesis of the study is that blood dilution detected by ultrasound is comparable with the reference method, perivascular flow probe around the aorta to determine cardiac output," the group wrote.
The study included 43 children between the ages of 1 month and 44 months who underwent corrective cardiac surgery. The children's heart function was evaluated both with a traditional perivascular flow probe and with a minimally invasive ultrasound technique that used catheters in their jugular veins and radial arteries to measure blood dilution following saline injection. After surgery, the patients underwent five consecutive cardiac measurements using both methods.
The ultrasound sensors showed a similar precision for measuring cardiac output when compared with the results obtained using the perivascular flow probe, the group found. The mean value for cardiac output measured by ultrasound was 1.28 L/min, while the mean value for cardiac output measured by perivascular flow probe was 1.20 L/min.
The technique is promising because it is easy to use with children who have these catheters already in place for surgery, Sigurdsson said in a statement about the study released by the American Society of Anesthesiologists (ASA).
"Our results demonstrate that this technology was not only easily adaptable in young children but also very accurate and precise," he said.
But more research is needed, and the technology for monitoring cardiac output in children needs to develop, according to an accompanying editorial written by lead author Dr. Christine Trieu and colleagues from the University of Los Angeles (UCLA) Medical Center.
"Despite the encouraging results from this study, there are still many challenges in developing the ideal cardiac output monitor for pediatric patients," Trieu et al wrote. "The perfect pediatric cardiac output monitor would have to be size unlimited, accurate, reproducible, continuous, have a rapid response time, [be] noninvasive, user-friendly, operator independent, [and] cost-effective. ... No such device is in existence for either adult or pediatric patients yet. However, if we can overcome ... an unfavorable industrial interest and strict research constraints ... then innovation will surely drive the invention of such a device in the future."
![Examples of ultrasound findings and techniques. (A) Images in a 39-year-old male patient with a mass in the left thigh. The mass is heterogeneous on the B-mode US image (compared with the patient in D) and showed increased microvascularity (superb microvascular imaging [SMI]) and shear-wave elastography (SWE) values. Undifferentiated pleomorphic sarcoma was diagnosed at biopsy (with pleomorphic rhabdomyosarcoma in surgical specimen). (B) Images in an 18-year-old male patient with a mass in the left leg. The mass is hypoechoic on the B-mode image, with no other findings suggestive of malignancy. The lesion is in contact with the cortex of the tibia, which is slightly irregular. CT revealed a doubtful anteromedial tibial erosion. The microvascular study demonstrated high vascularization, suggestive of malignancy. Periosteal Ewing sarcoma was diagnosed with both histologic and immunohistochemical confirmation. (C) Images in a 69-year-old female patient with a lump growing on the outside of the left leg. Multiple SWE examinations were performed (please note the high values obtained in the measurements, whereas the color map highlights the stiffness relative to adjacent tissues). SMI showed areas of increased vascularization to target for sampling. Undifferentiated spindle cell sarcoma was diagnosed at biopsy, with residual leiomyosarcoma in the surgical specimen after neoadjuvant therapy. (D) Images in a 56-year-old female patient with a mass in the right thigh. The mass is heterogeneous at both B-mode ultrasound (similar to patient A) and MRI (coronal T2-weighted spectral attenuated inversion recovery [SPAIR]; T1-weighted pre-contrast and postcontrast imaging), which even shows uptake after the administration of paramagnetic contrast material, which is traditionally suggestive of malignancy. Low values at SMI and elastography are suggestive of benignity. Spindle cell lipoma was diagnosed at biopsy, with atypical spindle cell lipomatous tumor in the surgical specimen.](https://img.auntminnie.com/mindful/smg/workspaces/default/uploads/2026/08/images-radiol250278fig2.APCFLSvX6p.jpg?auto=format%2Ccompress&dpr=2&fit=crop&h=167&q=70&w=250)
