Effects of bodyposition on arterial oxygenation in acute stroke patients

Abstract

OBJECTIVE: Hypoxemia is an important factor that increases cerebral damage in acute stroke patients. In conjunction with the growing importance of stroke intensive care units, there has been an increase in studies reporting on the correlation between oxygenation and the body position in acute stroke patients with hemiparesis. This study was planned to evaluate the relationship between oxygen saturation (SaO2) and position in acute stroke patients.

METHODS: : Acute stroke patients followed in the Neurology Department of Ankara Numune Hospital between July 2000 and June 2001 were included in this study.

The SaO2, pulse and blood pressure values were recorded initially, and at the 15th, 30th and 60th minutes in patients lying on either their paretic or healthy side in the lateral decubitus position on the 1st, 3rd and 7th days. Characteristics of the lesions were determined on computerized tomography (CT). Clinical parameters (consciousness, degree of paresis, functional disability, coma scores, and prognosis) were also recorded.

RESULTS: The 50 patients (19 male, 31 female) included in this study with the diagnosis of acute stroke had a mean age of 68.32±12.02. CT imaging revealed hematoma in 19 of the patients, infarct in 30 and hemorrhagic infarct in 1.

Arterial oxygen saturation (SaO2) values of the subjects recorded initially and at the 15th, 30th and 60th min from the healthy side in the lateral decubitus position in the first day of stroke were found to be higher than the paretic side (p<0.05 initially; p=0.002 15th min; p=0.013 30th min; and p=0.024 60th min). In female patients, SaO2 values were found to be lower than male patients in both recumbent positions (p=0.017 and p=0.020). SaO2 values in the hematoma group were lower than in the infarct group (p=0.038). SaO2 values of patients who died were lower than of those alive on the 3rd day (p=0.013 initially; p=0.012 30th min; p=0.020 60th min). SaO2 values in the sustained recumbent position demonstrated improvement over time (p=0.042).

There was no relation between position and the pulse rate, whereas systolic blood pressure values were found to be higher in patients lying on the healthy side (p=0.013 initially; p=0.009 15th min; p=0.017 30th min).

CONCLUSION: Our findings suggest that positioning of the patient in the lateral decubitus position on the healthy side may provide optimal oxygen saturation in addition to medical treatment.