G Model RESUS-5931; No. of Pages 1
ARTICLE IN PRESS Resuscitation xxx (2014) xxx–xxx
Contents lists available at ScienceDirect
Resuscitation journal homepage: www.elsevier.com/locate/resuscitation
Letter to the Editor Regional cerebral oxygen saturation monitoring during cardiac arrest Sir, The paper by Ahn et al.1 and the accompanying editorial make interesting reading, but there is an addition factor that needs to be considered when interpreting data when using near-infrared spectroscopy (NIRS). As saturations fall, this methodology becomes unreliable. This is seen with pulse oximetry; when saturations fall below 75%, it becomes inaccurate and unreliable.2,3 Similar findings have been reported when using NIRS to monitor cerebral oxygenation. In a calibration study on healthy volunteers,4 at low saturations, especially below 50%, there was poor correlation between cerebral haemoglobin oxygen saturation and jugular venous saturation. In the current study, the majority of readings of regional cerebral oxygen saturation (rSO2 ) in patients during cardiac arrest were below 50%. No evidence is provided of calibration of the device used at these low values. Furthermore there is also evidence that in healthy volunteers, cerebral oxygenation may be influenced by arterial carbon dioxide concentration5,6 but no information is provided to indicate if this was controlled in patients in this study. Before making claims that rSO2 may be a real-time, non-invasive marker of quality of resuscitation, more evidence is required demonstrating that it is accurately measuring what is happening at a tissue level in the brains of patients during a cardiac arrest and what factors need to be taken into account when interpreting the data.
References 1. Ahn A, Nasir A, Malik H, D’Orazi F, Parnia S. A pilot study examining the role of regional cerebral oxygen saturation monitoring as a marker of return of spontaneous circulation in shockable (VF/VT) and non-shockable (PEA/Asystole) causes of cardiac arrest. Resuscitation 2013;84:1713–6. 2. Trivedi NS, Ghouri AF, Lai E, Shah NK, Barker SJ. Pulse oximeter performance during desaturation and resaturation: a comparison of seven models. J Clin Anesth 1997;9:184–8. 3. Carter BG, Carlin JB, Tibballs J, Mead H, Hochmann M, Osborne A. Accuracy of two pulse oximeters at low arterial hemoglobin-oxygen saturation. Crit Care Med 1998;26:1128–33. 4. Pollard V, Prough DS, DeMelo AE, Deyo DJ, Uchida T, Stoddart HF. Validation in volunteers of a near-infrared spectroscope for monitoring brain oxygenation in vivo. Anesth Analg 1996;82:269–77. 5. Pollard V, Prough DS, DeMelo AE, Deyo DJ, Uchida T, Widman R. The influence of carbon dioxide and body position on near-infrared spectroscopic assessment of cerebral hemoglobin oxygen saturation. Anesth Analg 1996;82: 278–87. 6. Tateishi A, Maekawa T, Soejima Y, et al. Qualitative comparison of carbon dioxide-induced change in cerebral near-infrared spectroscopy versus jugular venous oxygen saturation in adults with acute brain disease. Crit Care Med 1995;23:1734–8.
Carl Gwinnutt Salford Royal Hospital Foundation Trust, 9 Coleridge Barns, Chillington, Kingsbridge, Devon TQ7 2HR, United Kingdom E-mail address: [email protected] 24 December 2013 Available online xxx
Conflict of interest statement The author declares there is no conflict of interest.
http://dx.doi.org/10.1016/j.resuscitation.2013.12.037 0300-9572/© 2014 Elsevier Ireland Ltd. All rights reserved.
Please cite this article in press as: Gwinnutt C. Regional cerebral oxygen saturation monitoring during cardiac arrest. Resuscitation (2014), http://dx.doi.org/10.1016/j.resuscitation.2013.12.037
ARTICLE IN PRESS Resuscitation xxx (2014) xxx–xxx
Contents lists available at ScienceDirect
Resuscitation journal homepage: www.elsevier.com/locate/resuscitation
Letter to the Editor Regional cerebral oxygen saturation monitoring during cardiac arrest Sir, The paper by Ahn et al.1 and the accompanying editorial make interesting reading, but there is an addition factor that needs to be considered when interpreting data when using near-infrared spectroscopy (NIRS). As saturations fall, this methodology becomes unreliable. This is seen with pulse oximetry; when saturations fall below 75%, it becomes inaccurate and unreliable.2,3 Similar findings have been reported when using NIRS to monitor cerebral oxygenation. In a calibration study on healthy volunteers,4 at low saturations, especially below 50%, there was poor correlation between cerebral haemoglobin oxygen saturation and jugular venous saturation. In the current study, the majority of readings of regional cerebral oxygen saturation (rSO2 ) in patients during cardiac arrest were below 50%. No evidence is provided of calibration of the device used at these low values. Furthermore there is also evidence that in healthy volunteers, cerebral oxygenation may be influenced by arterial carbon dioxide concentration5,6 but no information is provided to indicate if this was controlled in patients in this study. Before making claims that rSO2 may be a real-time, non-invasive marker of quality of resuscitation, more evidence is required demonstrating that it is accurately measuring what is happening at a tissue level in the brains of patients during a cardiac arrest and what factors need to be taken into account when interpreting the data.
References 1. Ahn A, Nasir A, Malik H, D’Orazi F, Parnia S. A pilot study examining the role of regional cerebral oxygen saturation monitoring as a marker of return of spontaneous circulation in shockable (VF/VT) and non-shockable (PEA/Asystole) causes of cardiac arrest. Resuscitation 2013;84:1713–6. 2. Trivedi NS, Ghouri AF, Lai E, Shah NK, Barker SJ. Pulse oximeter performance during desaturation and resaturation: a comparison of seven models. J Clin Anesth 1997;9:184–8. 3. Carter BG, Carlin JB, Tibballs J, Mead H, Hochmann M, Osborne A. Accuracy of two pulse oximeters at low arterial hemoglobin-oxygen saturation. Crit Care Med 1998;26:1128–33. 4. Pollard V, Prough DS, DeMelo AE, Deyo DJ, Uchida T, Stoddart HF. Validation in volunteers of a near-infrared spectroscope for monitoring brain oxygenation in vivo. Anesth Analg 1996;82:269–77. 5. Pollard V, Prough DS, DeMelo AE, Deyo DJ, Uchida T, Widman R. The influence of carbon dioxide and body position on near-infrared spectroscopic assessment of cerebral hemoglobin oxygen saturation. Anesth Analg 1996;82: 278–87. 6. Tateishi A, Maekawa T, Soejima Y, et al. Qualitative comparison of carbon dioxide-induced change in cerebral near-infrared spectroscopy versus jugular venous oxygen saturation in adults with acute brain disease. Crit Care Med 1995;23:1734–8.
Carl Gwinnutt Salford Royal Hospital Foundation Trust, 9 Coleridge Barns, Chillington, Kingsbridge, Devon TQ7 2HR, United Kingdom E-mail address: [email protected] 24 December 2013 Available online xxx
Conflict of interest statement The author declares there is no conflict of interest.
http://dx.doi.org/10.1016/j.resuscitation.2013.12.037 0300-9572/© 2014 Elsevier Ireland Ltd. All rights reserved.
Please cite this article in press as: Gwinnutt C. Regional cerebral oxygen saturation monitoring during cardiac arrest. Resuscitation (2014), http://dx.doi.org/10.1016/j.resuscitation.2013.12.037
