Do acute stroke patients develop hypocapnia? A systematic review and meta-analysis.

PURPOSE

Carbon dioxide (CO) is a potent cerebral vasomotor agent. Despite reduction in CO levels (hypocapnia) being described in several acute diseases, there is no clear data on baseline CO values in acute stroke. The aim of the study was to systematically assess CO levels in acute stroke.

MATERIAL AND METHODS

Four online databases, Web of Science, MEDLINE, EMBASE and CENTRAL, were searched for articles that described either partial pressure of arterial CO (PaCO) and end-tidal CO (EtCO) in acute stroke.

RESULTS

After screening, based on predefined inclusion and exclusion criteria, 20 studies were retained. There were 5 studies in intracerebral hemorrhage and 15 in ischemic stroke, totalling 660 stroke participants. Acute stroke was associated with a significant decrease in CO levels compared to controls. Cerebral haemodynamic studies using transcranial Doppler ultrasonography demonstrated a significant reduction in cerebral blood flow velocities and cerebral autoregulation in acute stroke patients.

CONCLUSION

The evidence from this review suggests that acute stroke patients are significantly more likely than controls to be hypocapnic, supporting the value of routine CO assessment in the acute stroke setting. Further studies are required in order to evaluate the clinical impact of these findings.