Retrospective analysis of the hemodynamic consequences of prehospital supplemental oxygen in acute stroke

• Published in: The American journal of emergency medicine Vol. 38; no. 10; pp. 2125 - 2129
• Main Authors: Dylla, Layne, Cushman, Jeremy T., Abar, Beau, Benesch, Curtis, Jones, Courtney M.C., O'Banion, M. Kerry, Adler, David H.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.10.2020; Elsevier Limited
• Subjects: Acute ischemic stroke; Aged; Aged, 80 and over; Analysis of Variance; Arterial Pressure - drug effects; Arterial Pressure - physiology; Blood flow; Blood pressure; Cardiovascular disease; Cerebral blood flow; Coronary vessels; Edema; Emergency; Emergency medical care; Emergency Service, Hospital - organization & administration; Female; Heart rate; Hemodynamics; Hemodynamics - drug effects; Hemodynamics - immunology; Humans; Hyperoxia; Hypotension; Hypoxia; Ischemia; Male; Medical records; Metabolism; Metabolites; Middle Aged; Mortality; Oxygen; Oxygen - adverse effects; Oxygen - pharmacology; Oxygen - therapeutic use; Oxygen Inhalation Therapy - methods; Oxygen Inhalation Therapy - standards; Oxygen Inhalation Therapy - statistics & numerical data; Oxygenation; Prehospital; Pulse oximetry; Regression analysis; Retrospective Studies; Stroke; Stroke - drug therapy; Stroke - physiopathology; Sulfur dioxide; Variance analysis; Vital signs; CPP; CBF; HR; SD; DBP; NIPPV; bpm; ED; SBP; CAD; MV; EMS; AIS; NRBM; TIA; Prehospital; CVA; mRS; GWTG-S; PaO2; Acute ischemic stroke; Hyperoxia; sO2; MAP; COPD; PVD; coronary artery disease; mechanical ventilation; Get with the Guidelines-Stroke; systolic blood pressure; peripheral vascular disease; emergency medical services; modified Rankin Scale; non-invasive positive pressure ventilation; diastolic blood pressure; supplemental oxygen; heart rate; beats per minute; PaO 2; mean arterial pressure; transient ischemic attack; chronic obstructive pulmonary disorder; emergency department; cerebrovascular accident; partial arterial pressure of oxygen; acute ischemic stroke; cerebral blood flow; sO 2; non-rebreather mask; cerebral perfusion pressure; standard deviation
• ISSN: 0735-6757; 1532-8171; 1532-8171
• DOI: 10.1016/j.ajem.2020.07.021

Hyperoxia, the delivery of high levels of supplemental oxygen (sO2) despite normoxia, may increase cerebral oxygenation to penumbral tissue and improve stroke outcomes. However, it may also alter peripheral hemodynamic profiles with potential negative effects on cerebral blood flow (CBF). This study examines the hemodynamic consequences of prehospital sO2 in stroke. A retrospective analysis of adult acute stroke patients (aged ≥18 years) presenting via EMS to an academic Comprehensive Stroke Center between January 1, 2013 and December 31, 2017 was conducted using demographic and clinical characteristics obtained from Get with the Guidelines-Stroke registry and subjects' medical records. Outcomes were compared across three groups based on prehospital oxygen saturation and sO2 administration. Chi-square, ANOVA, and multivariable linear regression were used to determine if sO2 was associated with differences in peripheral hemodynamic profiles. All subjects had similar initial EMS vitals except for oxygen saturation. However, both univariate and multivariable analysis revealed that hyperoxia subjects had slightly lower average ED mean arterial pressures (MAP) compared to normoxia (Cohen's d = 0.313). Prehospital-initiated hyperoxia for acute stroke is associated with a small, but significant decrease in average ED MAP, without changes in heart rate, compared to normoxia. While limited by the inability to link changes in peripheral hemodynamical profiles directly to changes in CBF, this study suggests that hyperoxia may result in a relative hypotension. Further studies are needed to determine if this small change in peripheral vascular resistance translates into a clinically significant reduced CBF.