Evaluation of Local Skeletal Muscle Blood Flow in Manipulative Therapy by Diffuse Correlation Spectroscopy

Manipulative therapy (MT) is applied to motor organs through a therapist’s hands. Although MT has been utilized in various medical treatments based on its potential role for increasing the blood flow to the local muscle, a quantitative validation of local muscle blood flow in MT remains challenging due to the lack of appropriate bedside evaluation techniques. Therefore, we investigated changes in the local blood flow to the muscle undergoing MT by employing diffuse correlation spectroscopy, a portable and emerging optical measurement technology that non-invasively measures blood flow in deep tissues. This study investigated the changes in blood flow, heart rate, blood pressure, and autonomic nervous activity in the trapezius muscle through MT application in 30 volunteers without neck and shoulder injury. Five minutes of MT significantly increased the median local blood flow relative to that of the pre-MT period (p < 0.05). The post-MT local blood flow increase was significantly higher in the MT condition than in the control condition, where participants remained still without receiving MT for the same time (p < 0.05). However, MT did not affect the heart rate, blood pressure, or cardiac autonomic nervous activity. The post-MT increase in muscle blood flow was significantly higher in the participants with muscle stiffness in the neck and shoulder regions than in those without (p < 0.05). These results suggest that MT could increase the local blood flow to the target skeletal muscle, with minimal effects on systemic circulatory function.

Increased interhemispheric asymmetry of cerebral blood flow in comatose adult patients on extracorporeal membrane oxygenation

Extracorporeal membrane oxygenation (ECMO) is a mechanical circulatory support method that is associated with a high burden of neurologic injury, but neurologic examination and imaging of this population presents prohibitive medical and logistical challenges. Diffuse correlation spectroscopy (DCS) can measure relative cerebral blood flow (rBF) non-invasively at the bedside. In this study we observed interhemispheric differences in rBF in response to mean arterial pressure (MAP) changes in adult ECMO recipients. Thirteen patients were recruited (ages 21-78, 7 with cardiac arrest, 4 with acute heart failure, 2 with acute respiratory distress syndrome). They were dichotomized via Glasgow Coma Scale Motor score (GCS-M) into comatose (GCS-M ≤ 4; n=4) and non-comatose (GCS-M > 4; n=9) groups. Comatose patients had more interhemispheric rBF asymmetry (ASYM_rBF) vs. non-comatose patients over a range of MAP values, (29% [IQR 23-34%] vs. 11% [IQR 8-13%], p=0.009). ASYM_rBF in comatose patients resolved near a MAP range of 70-80 mm Hg, while rBF remained symmetric through a wider MAP range in non-comatose patients. Associations between post-oxygenator pCO2 or pH vs. ASYM_rBF individually did not meet significance, though the linear model slopes were different between comatose and non-comatose subgroups. Here we have demonstrated asymmetric cerebral autoregulation in comatose ECMO patients.

Noninvasive Optical Monitoring of Cerebral Blood Flow and EEG Spectral Responses after Severe Traumatic Brain Injury: A Case Report

Survivors of severe brain injury may require care in a neurointensive care unit (neuro-ICU), where the brain is vulnerable to secondary brain injury. Thus, there is a need for noninvasive, bedside, continuous cerebral blood flow monitoring approaches in the neuro-ICU. Our goal is to address this need through combined measurements of EEG and functional optical spectroscopy (EEG-Optical) instrumentation and analysis to provide a complementary fusion of data about brain activity and function. We utilized the diffuse correlation spectroscopy method for assessing cerebral blood flow at the neuro-ICU in a patient with traumatic brain injury. The present case demonstrates the feasibility of continuous recording of noninvasive cerebral blood flow transients that correlated well with the gold-standard invasive measurements and with the frequency content changes in the EEG data.