Transcranial Color Duplex Ultrasound: A Reliable Tool for Cerebral Hemodynamic Assessment in Brain Injuries

Predictive value of TCCD and regional cerebral oxygen saturation for detecting early postoperative brain injury

OBJECTIVE

This study aims to analyze the risk factors for early postoperative brain injury in patients undergoing cardiovascular surgery and explore the predictive value of transcranial color Doppler (TCCD) and regional cerebral oxygen saturation (rSO2) for detecting early postoperative brain injury in cardiovascular surgery patients.

METHODS

A total of 55 patients undergoing cardiovascular surgery with cardiopulmonary bypass in Changzhou No.2 The People's Hospital of Nanjing Medical University were included in this study. Neuron-specific enolase (NSE) concentration was measured 24 h after operation. Patients were divided into brain injury (NSE ≥ 16.3 ng/mL) and normal (0 < NSE < 16.3 ng/mL) groups according to the measured NSE concentration. The clinical outcomes between the two groups were compared, including decreased rSO2 and cerebral blood flow (as measured by TCCD) levels. The risk factors of early postoperative brain injury were analyzed by multivariate logistic regression analysis, and the significant variables were analyzed by receiver operating characteristic (ROC) analysis.

RESULTS

A total of 50 patients were included in this study, with 20 patients in the brain injury group and 30 patients in the normal group. Cardiopulmonary bypass time (min) (107 ± 29 vs. 90 ± 28, P = 0.047) and aortic occlusion time (min) (111 (IQR 81-127) vs. 87 (IQR 72-116), P = 0.010) were significantly longer in the brain injury group than in the normal group. Patients in the brain injury group had greater decreased rSO2 (%) (27.0 ± 7.3 vs. 17.5 ± 6.1, P < 0.001) and cerebral blood flow (%) (44.9 (IQR 37.8-69.2) vs. 29.1 (IQR 12.0-48.2), P = 0.004) levels. Multivariate logistic regression analysis suggested that decreased rSO2 and cerebral blood flow levels, aortic occlusion time, and history of atrial fibrillation were independent risk factors for early postoperative brain injury (P < 0.05). ROC analysis reported that the best cutoff values for predicting early postoperative brain injury were 21.4% and 37.4% for decreased rSO2 and cerebral blood flow levels, respectively (P < 0.05).

CONCLUSION

The decreased rSO2 and cerebral blood flow levels, aorta occlusion time, and history of atrial fibrillation were independent risk factors for early postoperative brain injury. TCCD and rSO2 could effectively monitor brain metabolism and cerebral blood flow and predict early postoperative brain injury.

Assessment of cerebral blood flow velocities, brain midline shift and optic nerve sheath diameter by ultrasound in patients undergoing elective craniotomy: A prospective observational feasibility study

BACKGROUND

Brain ultrasound allows measuring the cerebral flow velocity, brain midline shift and optic nerve sheath diameter. Literature is scarce in determining the feasibility to perioperatively perform these measurements altogether and the cerebrovascular behavior in patients scheduled for elective craniotomy.

METHODS

We assessed bilateral cerebral flow velocities, composite index, brain midline shift and optic nerve sheath diameter by cerebral ultrasound in patients scheduled for elective craniotomy before anesthetic induction, at extubation, and at 6 and 24 h after. The aim was to assess the feasibility of brain ultrasound in patients for elective craniotomy and to describe the changes in cerebral flow velocities, brain midline shift and optic nerve sheath diameter from baseline values at different times in the postoperative period.

RESULTS

Sixteen patients were included, of these two were excluded from analysis due to an inadequate sonographic window. There were no changes throughout the study regarding cerebral flow velocity, brain midline shift nor optic nerve sheath diameter assessments. All parameters were maintained in the physiological range without significant variations during the procedure. No perioperative complications were detected.

CONCLUSIONS

The results of our study show the feasibility to perform a perioperative assessment of cerebral flow velocity, brain midline shift or optic nerve sheath diameter jointly and successfully to obtain additional information of baseline cerebral hemodynamics in patients scheduled for elective craniotomy and their postoperative changes during the first 24 h. Future studies with lager samples are needed to address the efficacy of cerebral ultrasound as a monitoring tool.

Transcranial Color Coded Duplex Sonography Findings in Stroke Patients Undergoing Rehabilitation: An Observational Study

Background  Transcranial color-coded duplex sonography (TCCD) provides information on intracranial blood flow status in stroke patients and can predict rehabilitation outcomes.

Objective  This study aimed to assess middle cerebral artery (MCA) parameters using TCCD in MCA territory stroke patients admitted for rehabilitation and correlate with clinical outcome measures.

Materials and Methods  Patients aged 18 to 65 years with a first MCA territory stroke, within 6 months of onset were recruited. The clinical outcome scales and TCCD parameters were assessed at both admission and discharge. The scales used were the Scandinavian stroke scale (SSS), Barthel Index (BI), modified Rankin Scale (mRS), Fugl–Meyer upper extremity scale (FMA-UE), modified motor assessment scale (mMAS) scores. TCCD parameters measured were MCA peak systolic, end diastolic, mean flow velocities (MFV), and index of symmetry (SI) and were correlated with clinical scores.

Results  Fourteen patients were recruited with median age of 56.5 years, median duration of stroke was 42.5 days. Mean flow velocities of affected and unaffected MCA were 46.2 and 50.7 cm/s, respectively. Flow velocities and SI did not change between the two assessments. There was significant improvement in clinical outcome scores at discharge. Significant correlation was observed for patient group with SI > 0.9 at admission with FMA-UE, SSS, and BI scores at discharge ( p  < 0.05).

Conclusion  Flow velocity parameters did not change during in-patient rehabilitation. Patients with symmetric flow at admission had improved clinical outcomes measure scores at discharge. Thus SI can predict rehabilitation outcomes in stroke survivors.

Transcranial color-coded duplex sonography assessment of cerebrovascular reactivity to carbon dioxide: an interventional study

Background

The investigation of CO₂ reactivity (CO₂-CVR) is used in the setting of, e.g., traumatic brain injury (TBI). Transcranial color-coded duplex sonography (TCCD) is a promising bedside tool for monitoring cerebral hemodynamics. This study used TCCD to investigate CO₂-CVR in volunteers, in sedated and mechanically ventilated patients without TBI and in sedated and mechanically ventilated patients in the acute phase after TBI.

Methods

This interventional investigation was performed between March 2013 and February 2016 at the surgical ICU of the University Hospital of Zurich. Ten volunteers (group 1), ten sedated and mechanically ventilated patients (group 2), and ten patients in the acute phase (12–36 h) after severe TBI (group 3) were included. CO₂-CVR to moderate hyperventilation (∆ CO₂ -5.5 mmHg) was assessed by TCCD.

Results

CO₂-CVR was 2.14 (1.20–2.70) %/mmHg in group 1, 2.03 (0.15–3.98) %/mmHg in group 2, and 3.32 (1.18–4.48)%/mmHg in group 3, without significant differences among groups.

Conclusion

Our data did not yield evidence for altered CO₂-CVR in the early phase after TBI examined by TCCD.

Trial registration

Part of this trial was performed as preparation for the interventional trial in TBI patients (clinicaltrials.gov NCT03822026, 30.01.2019, retrospectively registered).

[Clinical efficacy of restrictive fluid management in patients with severe traumatic brain injury]

OBJECTIVE

To investigate the effects of restrictive fluid management in patients with severe traumatic brain injury (sTBI).

METHODS

Between January, 2019 and June, 2020, we randomly assigned 51 postoperative patients (stay in the ICU of no less than 7 days) with sTBI into treatment group (n=25) with restrictive fluid management and the control group (n=26) with conventional fluid management. The data of optic nerve sheath diameter (ONSD), middle cerebral artery pulsatility index (MAC- PI), neuron-specific enolase (NSE) level, inferior vena cava (IVC) diameter, Glascow Coma Scale (GCS) score, mean arterial blood pressure, heart rate, and fluid balance of the patients were collected at ICU admission and at 1, 3 and 7 days after ICU admission, and the duration of mechanical ventilation, ICU stay, and 28-day mortality were recorded.

RESULTS

The cumulative fluid balance of the two groups were positive on day 1 and negative on days 3 and 7 after ICU admission; at the same time points, the patients in the treatment group had significantly greater negative fluid balance than those in the control group (P < 0.05). In both of the groups, the ONSD and MCA-PI values were significantly higher on day 1 than the baseline (P < 0.05), reached the peak levels on day 3, and decreased on day 7; at the same time point, these values were significantly lower in the treatment group than in the control group (P < 0.05). No significant difference was found in NSE level on day 1 between the two groups (P>0.05); on day 3, NSE level reached the peak level and was significantly higher in the control group (P < 0.05); on day 7, NSE level was lowered the level of day 1 in the treatment group but remained higher than day 1 level in the control group. The 28-day mortality rate did not differ significantly between the two groups (16.00% vs 23.08%, P>0.05); the duration of mechanical ventilation, length of ICU stay, and the number of tracheotomy were all significantly shorter or lower in the treatment group than in the control group (P < 0.05).

CONCLUSIONS

Restrictive fluid management can reduce cerebral edema and improve the prognosis but does not affect the 28-day mortality of patients with sTBI.

Multimodality Neuromonitoring in Adult Traumatic Brain Injury: A Narrative Review

Neuromonitoring plays an important role in the management of traumatic brain injury. Simultaneous assessment of cerebral hemodynamics, oxygenation, and metabolism allows an individualized approach to patient management in which therapeutic interventions intended to prevent or minimize secondary brain injury are guided by monitored changes in physiologic variables rather than generic thresholds. This narrative review describes various neuromonitoring techniques that can be used to guide the management of patients with traumatic brain injury and examines the latest evidence and expert consensus guidelines for neuromonitoring.