CORRESPONDENCE But in all these studies, it is not easy to set a cut-off point Letter: Early Moderate Hyperoxemia does of arterial oxygen tension as PaO fluctuates relatively quickly. not Predict Outcome after Aneurysmal In the current study, an average of PaO was used and it to a Subarachnoid Hemorrhage certain extent demonstrated the whole oxygenation state, but it To the Editor: still cannot comprehensively reflect the volatility of PaO . We have read with interest the observational cohort study For this reason, we boldly put forward a new index: PaO - by Lång et al evaluating the impact of hyperoxia on Glasgow load (Figure), which can more comprehensively demonstrate the scale score and mortality at 3-month in patients with aneurysmal fluctuation of PaO from a mathematical standpoint. Of course, subarachnoid hemorrhage (SAH). In contrast to several studies, the cut-off point of PaO (60 mm Hg) in this schematic diagram no significant correlation was found between moderate hyperoxia is set at random and needs to be reappraised. As a new index, the (97.5-150 mm Hg) and unfavorable outcomes in this study. deficiency is obvious as the utility has not been demonstrated in Efforts have been made to assess the relationship between previous studies, but we still hope these suggestions will be helpful different PaO levels and mortality in patients with brain 2 for future researches. injury, including SAH, ischemic stroke, traumatic or sponta- neous intracranial hemorrhage. But the conclusions were contro- Disclosure versial, which could partly be explained by different definitions of The authors have no personal, financial, or institutional interest in any of the 2,3 hyperoxia, heterogeneity of patients. drugs, materials, or devices described in this article. For a patient with brain injury, oxygen is routinely supplied to avoid hypoxemia. Under this circumstance, hyperoxia was Kailei Du, MM common but always temporal as the oxygen supply concentration Yanfei Shen, MD be adjusted. Thus, using only one specific PaO value within Intensivecareunit, 2,4,5 24 h to represent the whole oxygen situation would increase Dongyang People’s Hospital, the risk of bias conclusion, which may also contribute to the Jinhua City, Zhejiang, controversial conclusions. People’s Republic of China REFERENCES 1. Lang M, Raj R, Skrifvars MB, et al. Early moderate hyperoxemia does not predict outcome after aneurysmal subarachnoid hemorrhage. Neurosurgery. 2016;78(4):540-545. 2. Rincon F, Kang J, Maltenfort M, et al. Association between hyperoxia and mortality after stroke: a multicenter cohort study. Crit Care Med. 2014;42(2):387- 3. Fallenius M, Raj R, Reinikainen M, Bendel S, Skrifvars MB. Association between high arterial oxygen tension and long-term survival after spontaneous intracerebral hemorrhage. Crit Care Med. 2016;44(1):180-187. 4. Raj R, Bendel S, Reinikainen M, et al. Hyperoxemia and long-term outcome after traumatic brain injury. Crit Care. 2013;17(4):R177. 5. Young P, Beasley R, Bailey M, et al. The association between early arterial oxygenation and mortality in ventilated patients with acute ischaemic stroke. Crit Care Resusc. 2012;14(1):14-19. 10.1093/neuros/nyx033 FIGURE. Definition of PaO -load: the red area is termed as PaO -load. 2 2 E252 | VOLUME 80 | NUMBER 5 | MAY 2017 www.neurosurgery-online.com
Neurosurgery – Oxford University Press
Published: May 1, 2017
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