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The S troke O xygen S upplementation PILOT Study. C. Roffe, K. Ali, A. Warusevitane, S. Sills, S. Pountain, P Jones, R Gray, P. Crome North Staffordshire Combined Healthcare Trust University Hospital of North Staffordshire Brighton and Sussex University Hospital
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The Stroke Oxygen Supplementation PILOT Study C. Roffe, K.Ali, A. Warusevitane, S. Sills, S. Pountain, P Jones, R Gray, P. Crome North Staffordshire Combined Healthcare Trust University Hospital of North Staffordshire Brighton and Sussex University Hospital University Hospital Birmingham Keele University The North Staffordshire Medical Institute
Background Incidence of hypoxia 63% in the first 2 days Sulter et al, J Neurol Sci 2000;179:65-9.
Oxygen saturation within the first 72 hours of acute stroke Roffe et al, Stroke 2003;34:2641-2645.
Adverse effects of hypoxia after stroke IEarly deterioration 381 consecutive patients with acute stroke Oxygen saturation <90 doubles risk of early deterioration. Silva et al, Cerebrovasc Dis 2001;11(suppl 4):70
Adverse effects of hypoxia after stroke IIIncreased mortality • N=153 assessed from arrival and during transfers till ward admission • Hypoxia defined as SpO2<90 for >10% of assessment phase • Oxygen saturation lowest during transfers • Hypoxic pts are more likely to have a history of chest problems • Hypoxia doubles mortality, but no longer significant if corrected for stroke severity • No effect on long-term disability Rowat et al. Cerebrovasc Dis 2006;21:166-172.
Unexpected nocturnal hypoxia in stroke patients Time spent with an oxygen saturation <90% at night 52% more than 5 minutes 23% more than 30 minutes 15% more than 1 hour Roffe et al, Stroke 2003;34:2641-2645
Experimental Evidence • 100% oxygen increases oxygen delivery to the ischaemic brain in mice • Infarct size at 2 days reduced by 45% Shin, H. K. et al. Brain 2007 130:1631-1642 • 95% O2 reduced neurological deficit and infarct size in rats Liu et al J Cereb Blood Flow Metab. 2006;26:1274-84.
Routine oxygen supplementation No oxygen Oxygen No oxygen Oxygen Oxygen No oxygen All strokes Mild strokes SSS>40 (top) Severe strokes SSS £ 40 (bottom) Ronning and Guldvog, Stroke 1999;30:2033-37.
Selective high dose (45L/min) short burst oxygen supplementation Methods— • acute stroke <12 h and perfusion-diffusion "mismatch" on MRI • RCT of high-flow oxygen via mask for 8 hours (n=9) vs room air (n=7) Results— • Oxygen tended to improve stroke scale scores at 4 h and 1 week, and significantly at 24 h, but there was no significant difference at 3 months. • MRI lesion volumes were significantly reduced at 4 hours, but not subsequent time points. • Cerebral blood volume and blood flow within ischemic regions improved • More petechial hemorrhages (50% w oxygen vs 17% w room air) Singhal et al . Stroke. 2005;36:797-802.
National and international Stroke Guidelines UK National Clinical Guidelines for Stroke Arterial oxygen concentration should be maintained within normal limits 2004 Give Oxygen to maintain oxygen saturation at or above 95% 2008 European Stroke Initiative Recommendations for Stroke Management 2-4L/min when indicated in 2003 Oxygen if saturation<92% in 2007 American Stroke Association Guidelines Oxygen if saturation <95% in 2003 and 2005 Oxygen if saturation </=92% in 2007 National Clinical Guidelines for Stroke. RCP 2004, 2008, NICE 2008, EUSI 2004, ESO 2007; ASA, Stroke. 2003;34(4):1056-83, 2005;36:916-23, 2007;38:1655-1711.
StrokeOxygen PILOT Study Routine oxygen supplementation during the first three days after an acute stroke Prospective randomized open study
Effect of oxygen supplementation on oxygen saturation SpO2: oxygen saturation a Time corrected to a standard 8 hour night *p<0.05, **p<0.01, ***p<0.01
Neurological Outcomeat 1 week NIHSS: National Institute for Health Stroke Scale; ***p<0.001
Outcomes at 6 months mRS modified Rankin Scale;
Conclusion 1 This pilot study demonstrates • That routine oxygen supplementation effectively increased oxygen saturation when given in a non- intensive clinical environment • That oxygen supplementation was well tolerated without observable adverse effects • That the outcomes are feasible and deliver over 95% returns at 1 week (clinical) and 6 months (questionnaire)
Conclusion 2 This pilot study was not powered to look at neurological or functional outcomes or to do subgroup analyses Results so far are that routine oxygen supplementation • Led to a small but statistically significant improvement in neurological outcome at 1 week • Had no significant effect on mortality and functional outcome at 6 months A larger study is required to determine whether routine oxygen supplementation is effective in reducing neurological deficit and improving functional outcome