In our study, according to IVC diameter measurements we found that 34.1% of acute ischemic stroke patients admitted to ED were dehydrated. We also determined that dehydration is associated with poor prognosis in anterior circulation occlusions.
Rowat et al. [5] found that 36% of the patients with stroke had dehydration at the time of the first admission. The fact that our hospital is closer to the stroke center in our region may have contributed to the lower number of patients in our study who had dehydration. In the study by Rowat et al., 62% of the patients were found to be dehydrated at some point of time during their follow-up at the hospital. Several other similar studies have also suggested that intravascular volume is low in patients with ischemic stroke [3, 6]. Dehydration or decreased intravascular volume has been reported to be associated with adverse effects and outcomes in patients with acute ischemic stroke [5]. The resulting dehydration may predispose such patients to central nervous system hypoperfusion, which may exacerbate ischemic brain damage and lead to an increased propensity for renal dysfunction and thrombosis. As hypotension is typically linked to hypovolemia, the clinical picture is further complicated by the fact that 75% of patients with acute ischemic stroke present with elevated blood pressure [9].
A study by Liu et al. found that dehydration was associated with poor neurological outcomes and high treatment costs [21].
Candidates for endovascular or thrombolytic therapy may receive fast-acting antihypertensive drugs during the acute phase. In patients with low intravascular volume, this therapy can cause decreased cerebral perfusion and adverse effects. The detection of patients with low volume based on the IVC diameter, which is measured using bedside US, can be useful for earlier development and implementation of treatment strategies. IVC is a vessel with high compliance. Several studies have attempted to relate intrapleural pressure changes that occur during the respiratory cycle and measurements of IVC diameter to the volume status. Nette et al. reported that norepinephrine infusion in hemodialysis patients with low blood volume increased their SBP; however, it did not cause a significant change in their IVC diameter. This suggested that IVC diameter measurements are highly correlated with intravascular volume [22]. A study by Nagdev et al. on patients who underwent central venous catheterization found that an IC of > 50% was highly associated with low central venous pressure [15]. To the best of our knowledge, only one study (i.e., the study by Miller et al.) that used IVC measurements to evaluate intravascular volume in patients presenting with acute ischemic stroke found 63% of patients with low volume [23]. In contrast, our study found 34.1% of the patients to be hypovolemic. The study by Miller et al. had the important limitation of not including conditions that may affect IVC diameter measurements, such as right heart failure and pulmonary hypertension, in the exclusion criteria (23). In our study, the group with normal volume, based on CI measurements, had a mean SBP of 159 ± 35 mmHg, and the low volume group had a mean SBP of 163 ± 29 mmHg; there was no significant correlation between their mean SBP values. This suggests that although patients with low intravascular volume are expected to be hypotensive or normotensive, both groups have similar mean SBP values; therefore, the use of blood pressure as an indicator can be misleading for physicians during the assessment of volume status in patients presenting to the ED with acute ischemic stroke.
Most studies investigating the effect of dehydration on prognosis in patients with ischemic stroke found that dehydration was related to poor outcome. In addition, a study by Nadav et al. found that dehydration increased the risk of ischemic stroke in hospitalized patients [24].
Assessing intravascular volume in patients with stroke using IVC measurements helps identify patients who require fluid therapy. Dehydration is a cause of increased mortality in patients with stroke, and early fluid resuscitation may improve the prognosis in such patients.
Our study has some limitations. First, we did not use an invasive method, such as central venous pressure, for comparisons while evaluating the intravascular volume. As reported in the meta-analysis by Orso et al. [25], studies on the subject are heterogeneous, and ultrasound is clinician dependent. Finally, this study had a single-center design because our hospital is the stroke center in our region. This may have affected patient selection.