Cerebral blood flow change with fluid resuscitation in acute ischemic stroke

In acute ischemic stroke (AIS), cerebral autoregulation becomes dysfunctional, impacting the brain's ability to maintain cerebral blood flow (CBF) at adequate levels. Reperfusion of affected and nearby brain tissue in AIS is currently the aim of treatment in AIS, but the effectiveness of fluid resuscitation on increasing the CBF is debated. We investigated the hypothesis that early fluid resuscitation with normal saline bolus would improve CBF velocity in the initial resuscitation of patients with AIS. We conducted a prospective, quasi-experimental study on 30 patients in the early stages of AIS management. Patients had a National Institutes of Health Stroke Scale (NIHSS) score of 3 or higher. Patients met inclusion criteria if they were 18-90 years old and had time of stroke onset within 12 h. Patients with a severe underlying disability, hemorrhagic stroke, advanced directives for comfort care/hospice, as well as pregnant patients were excluded. Noninvasive hemodynamic monitoring was performed. We performed transcranial Doppler (TCD) insonation of the middle cerebral arteries (MCAs) to measure CBF velocity. Each patient received a 500-ml normal saline crystalloid bolus as a standardized intervention, then had hemodynamic and TCD measurements repeated. Analysis was limited to patients with stroke confirmed with neuroimaging. Mean flow velocity (MFV) was compared before and postreceiving the bolus in the MCA ipsilateral to the ischemic location. Thirty patients were analyzed who had confirmed AIS. The mean age was 53 ± 13 years, 50% were female, and the median NIHSS was 6 (interquartile range: 4-7). Outcomes measured included various cerebrovascular and cardiovascular parameters. Infusion of 500-mL normal saline bolus produced increases in systolic blood pressure (+7 mmHg, 95% confidence interval [CI] 0.6-13 mmHg) and stroke volume (SV) index (+2.2 ml/m2, 95% CI 0.3-4.1 ml/m2). The mean change in MFV was not statistically significant (+0.3 cm/s, 95% CI-3.7-4.3 cm/s). An adjusted model showed higher age and lower baseline SV index were not associated with improved MFV following administration of the fluid bolus. Our prospective study of AIS patients revealed that a fluid bolus improves hemodynamic parameters, but did not significantly increase CBF velocity. clinicaltrials.gov (identifier: NCT02056821).