Correlation between cerebral co-oximetry (rSO2) and outcomes in traumatic brain injury cases: A prospective, observational study

Evaluation of Morlet Wavelet Analysis for Artifact Detection in Low-Frequency Commercial Near-Infrared Spectroscopy Systems

Regional cerebral oxygen saturation (rSO2), a method of cerebral tissue oxygenation measurement, is recorded using non-invasive near-infrared Spectroscopy (NIRS) devices. A major limitation is that recorded signals often contain artifacts. Manually removing these artifacts is both resource and time consuming. The objective was to evaluate the applicability of using wavelet analysis as an automated method for simple signal loss artifact clearance of rSO2 signals obtained from commercially available devices. A retrospective observational study using existing populations (healthy control (HC), elective spinal surgery patients (SP), and traumatic brain injury patients (TBI)) was conducted. Arterial blood pressure (ABP) and rSO2 data were collected in all patients. Wavelet analysis was determined to be successful in removing simple signal loss artifacts using wavelet coefficients and coherence to detect signal loss artifacts in rSO2 signals. The removal success rates in HC, SP, and TBI populations were 100%, 99.8%, and 99.7%, respectively (though it had limited precision in determining the exact point in time). Thus, wavelet analysis may prove to be useful in a layered approach NIRS signal artifact tool utilizing higher-frequency data; however, future work is needed.

Effects of ultrasound-guided stellate ganglion block on the balance of the supply and demand of cerebral oxygen during permissive hypercapnia in patients undergoing shoulder arthroscopy in beach chair position

OBJECTIVE

To investigate the effects of ultrasound-guided stellate ganglion block (SGB) on the supply and demand balance of cerebral oxygen in patients with permissive hypercapnia (PHC) undergoing shoulder arthroscopy in a beach chair position (BCP).

METHOD

In this prospective study, a total of 86 patients who had shoulder arthroscopy were enrolled and divided into the stellate ganglion block group (SG group, n=43) and the control group (CN group, n=43) using a random number table method. Ultrasound-guided SGB was performed on patients' operation side at the 6th cervical vertebra (C6) anterior transverse tubercle level. Patients in the SG group were injected with 6ml mixture of 0.25% ropivacaine hydrochloride and 1% lidocaine hydrochloride, and those in the CN group with an equal amount of 0.9% normal saline (NS). The patients of both groups were placed in BCP for shoulder arthroscopy, and rapid induction of endotracheal intubation was performed for assisted or mechanical ventilation. Ventilation strategy was adjusted to gradually increase pulmonary end-tidal CO₂ (P_ETCO₂) during surgery. The rSO₂ levels of patients in both groups were recorded 10 min after being placed in supine position in the operation room (T0), 10 min after SGB (T1), 10 min after anesthesia induction in supine position (T2), 10 min after anesthesia induction in beach chair position (T3), 30 min after P_ETCO₂ was stabilized at 35 to 40 mmHg (T4) during surgery, and 30 min after P_ETCO₂ was stabilized at 45 to 50 mmHg (T5), respectively. The cerebral oxygen metabolic measures, including saturation of jugular bulb venous oxygen (SjvO₂), difference in artery-jugular venous oxygen content (DajvO₂) and cerebral oxygen extraction rate (CERO₂) of patients in the two groups at the time point mentioned above were compared. Hemodynamic parameters including arterial carbon dioxide partial pressure (PaCO₂), mean arterial pressure (MAP), heart rate (HR) and Saturation of Pulse Oxygen (SpO₂) were recorded. Cerebral desaturation episodes, nausea, vomiting and the use of vasoactive drugs during surgery were also recorded. The Mini-Mental State Examination score (MMSE) was recorded 1 day before and after surgery.

RESULTS

There was no significant difference in the comparison of SjvO₂, Da-jvO₂, CERO₂, PaCO₂, MAP, HR and SpO₂ between the two groups at T0-T5 (P>0.05); no significant differences were found in intra-group comparison of SjvO₂, Da-jvO₂, CERO₂ at T0-T4 (P>0.05); the level of SjvO₂ at T5 was higher than that at T4, and the levels of Da-jvO₂ and CERO₂ at T5 were markedly lower than those at T4 (P<0.05). No significant differences were found in the inter-group comparison of MAP, HR and SpO₂ at T0-T5 (P>0.05), while PaCO₂ was significantly higher at T4 than that at T5 (P<0.05). The rSO₂ levels of patients in both groups significantly decreased at T3, as compared with those at T0 (P<0.05); the rSO₂ levels markedly increased at T5 than those at T4 (P<0.05); and the rSO₂ levels showed more significant increase in SGB group than those in the CN group as the level of P_ETCO₂ rose.

CONCLUSION

Permissive hypercapnia resulting from proper ventilation can significantly increase the rSO₂ levels in patients who undergo shoulder arthroscopy in BCP, the effect of which was enhanced by SGB on patients' operation side to maintain well-balanced demand and supply of cerebral oxygen. (China Clinical Trial Registry, registration number ChiCTR2000033385, https://www.chictr.org.cn).

A Standardized Multimodal Neurological Monitoring Protocol-Guided Cerebral Protection Therapy for Venoarterial Extracorporeal Membrane Oxygenation Supported Patients

Background

The main objective of this study was to investigate the role of a multimodal neurological monitoring (MNM)-guided protocol in the precision identification of neural impairment and long-term neurological outcomes in venoarterial extracorporeal membrane oxygenation (VA-ECMO) supported patients.

Methods

We performed a cohort study that examined adult patients who underwent VA-ECMO support in our center between February 2010 and April 2021. These patients were retrospectively assigned to the “with MNM group” and the “without MNM group” based on the presence or absence of MNM-guided precision management. The differences in ECMO-related characteristics, evaluation indicators (precision, sensitivity, and specificity) of the MNM-guided protocol, and the long-term outcomes of the surviving patients were measured and compared between the two groups.

Results

A total of 63 patients with VA-ECMO support were retrospectively assigned to the without MNM group (n = 35) and the with MNM group (n = 28). The incidence of neural impairment in the without MNM group was significantly higher than that in the with MNM group (82.1 vs. 54.3%, P = 0.020). The MNM group exhibited older median ages [52.5 (39.5, 65.3) vs. 31 (26.5, 48.0), P = 0.008], a higher success rate of ECMO weaning (92.8 vs. 71.4%, P = 0.047), and a lower median duration of building ECMO [40.0 (35.0, 52.0) vs. 58.0 (48.0, 76.0), P = 0.025] and median ECMO duration days [5.0 (4.0, 6.2) vs. 7.0 (5.0, 10.5), P = 0.018] than the group without MNM. The MNM-guided protocol exhibited a higher precision rate (82.1 vs. 60.0%), sensitivity (95.7 vs. 78.9%), and specificity (83.3 vs. 37.5%) in identifying neural impairment in VA-ECMO support patients. There were significant differences in the long-term outcomes of survivors at 1, 3 and 6 months after discharge between the two groups (P < 0.05). However, the results showed no significant differences in ICU length of stay (LOS), hospital LOS, survival to discharge, or 28-day mortality between the two groups (P > 0.05).

Conclusion

The MNM-guided protocol is conducive to guiding intensivists in the improvement of cerebral protection therapy for ECMO-supported patients to detect and treat potential neurologic impairment promptly, and then improving long-term neurological outcomes after discharge.

Effect of Respiratory Physiological Changes on Optic Nerve Sheath Diameter and Cerebral Oxygen Saturation in Patients With Acute Traumatic Brain Injury

BACKGROUND

Severe traumatic brain injury (TBI) results in raised intracranial pressure (ICP). Ultrasonographic measurement of the optic nerve sheath diameter (ONSD) is a noninvasive method for the assessment of raised ICP. Manipulation of positive end-expiratory pressure (PEEP) and end-tidal carbon dioxide (ETCO2) are often used to optimize ICP and improve oxygenation in TBI patients. This study evaluated the effects of PEEP and ETCO2 on ONSD and regional cerebral oxygen saturation (rScO2) in patients with acute TBI.

METHODS

A total of 14 patients (11 males) aged older than 18 years with acute severe TBI were included in this study. ONSD and rScO2 were assessed before and after changes in PEEP from 5 to 10 cm H2O and in ETCO2 from 40 to 30 mm Hg on both pathologic and nonpathologic sides.

RESULTS

Increasing PEEP and reducing ETCO2 resulted in changes in ONSD and rScO2 on both pathologic and nonpathologic sides. On the pathologic side, ONSD and rScO2 were highest with a PEEP of 10 cm H2O:ETCO2 40 mm Hg combination and lowest with PEEP of 5 cm H2O:ETCO2 30 mm Hg (ONSD 5.24±0.49 vs. 4.27±0.36 mm, P<0.001; rScO2 70.7±9.91% vs. 66.3±9.75%, P<0.001); both PEEP and ETCO2 had significant effects on ONSD and rScO2 (P<0.001). On the nonpathologic side, ONSD and rScO2 were highest and lowest with PEEP of 10 cm H2O:ETCO2 40 mm Hg and PEEP of 5 cm H2O:ETCO2 30 mm Hg combinations, respectively (ONSD: 4.93±0.46 vs. 4.02±0.40 mm, P<0.001; rScO2: 74.77±8.30% vs. 70.69±8.12%, P<0.001). ETCO2 had a significant effect on rScO2 (P<0.001), but the impact of PEEP on rScO2 was not statistically significant (P=0.05).

CONCLUSION

Increasing PEEP resulted in significant increases in ONSD and rScO2, whereas reducing ETCO2 significantly decreased ONSD and rScO2.