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From the Department of Anaesthetics and Intensive Care Medicine, University of Wales College of Medicine, Heath Hospital, Heath Park, Cardiff, UK.
Address correspondence to: Dr. M. Shaaban Ali, Department of Anaesthesia, University of Wales College of Medicine, Cardiff CF14 4XN, UK. Phone: 0044-29-20-743110; Fax: 0044-29-20-747203; E mail: msali58{at}hotmail.com
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Abstract |
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Methods: Seventeen patients undergoing warm coronary artery bypass surgery were studied. NIRS was continuously monitored and was averaged before CPB, five, 20, 40, 60 min on CPB, five minutes before end of CPB and ten minutes after CPB to coincide with SjO2 measurements. Bypass temperature was maintained at 34–37°C.
Results: Bland and Altman analysis showed a bias (TOI–SjO2) of -6.7%, and wide limits of agreement (from 16% to -28%) between the two methods. In addition, mean TOI was lower than mean SjO2 during and after CPB. We observed a statistically significant correlation between arterial carbon dioxide and SjO2 measurements (r2=0.33; P=0.0003), but the former did not correlate with TOI values (r2=0.001; P=0.7).
Conclusion: Our results demonstrate a lack of agreement between SjO2 and TOI for monitoring cerebral oxygenation during cardiac surgery. We conclude that the two methods are not interchangeable.
CONTINUOUS or intermittent jugular bulb oxygen saturation (SjO2) measurements have been used to assess cerebral oxygenation during cardiac surgery.1 SjO2 50% (desaturation) has been detected during rewarming from cold cardiopulmonary bypass (CPB),2,3 and in the first 40 min of warm CPB (temperature 37°C).4 In addition, SjO2 50% during rewarming is associated with impaired cognitive function after CPB surgery.2
The unique ability of light in the near infrared range (700–1300 nm) to detect the oxygenation of living tissues was first described by Jobsis in 1977.5 Since that time, NIRS has emerged as a promising in vivo technique and as a continuous cerebral oxygenation monitor during cardiac surgery.6 NIRS has been used to study the changes in cerebral oxygenation in children and adults undergoing CPB surgery with or without deep hypothermic arrest7–9 and to monitor cerebral hemodynamics.10 In addition, it might be useful as a cerebral oxygenation monitor in patients undergoing carotid endarterectomy.11
The NIRO-300 is a new NIRS monitor introduced recently by Hamamatsu Photonics, Japan, which uses spatially-resolved spectroscopy (SRS) to provide not only the usual measurements of change in hemoglobin concentration, but also an absolute signal of the tissue oxygenation index (TOI) which is related to the averaged regional hemoglobin saturation.12,13 The SRS technique incorporates several detectors housed in a single probe placed over an area of 8 x 8 mm, and 4–5 cm from the light source fibre. A combination of these multi-distance measurements of optical attenuation with the usual multi-wavelength spectroscopy data allows calculation of the relative concentrations of deoxyhemoglobin and oxyhemoglobin in the illuminated tissue and therefore an index of the mean tissue hemoglobin saturation.13
The aim of this study was to evaluate the intra-operative use of the NIRO-300 for monitoring of TOI which may provide a non-invasive alternative to SjO2 monitoring in patients undergoing warm CABG, and to determine if the two methods are interchangeable.
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Methods |
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CPB was established using a membrane oxygenator and a roller pump with an arterial line filter. Perfusion was non-pulsatile with a flow rate of 2.4 L•min–1•m–2 body surface area. A pH-stat carbon dioxide management strategy (blood gas measurements corrected to body temperature) was employed. Nasopharyngeal temperature was maintained at 34–37°C and intermittent, antegrade warm blood cardioplegia (temperature 37°C) was administered to all patients. During CPB, anesthesia was maintained by isoflurane 0.5–1%.
The jugular bulb catheter (Hydrocath 16 G, 15–20 cm) was placed by retrograde cannulation of the right internal jugular vein and its position was checked radiologically. SjO2 samples were measured by a co-oximeter (Radiometer ABL 520, Radiometer, Ltd, Copenhagen, Denmark).
NIRO-300 probes were applied over the right supra-orbital region with an inter-optode distance of 5 cm. Continuous monitoring of TOI was averaged to synchronize with the SjO2 measurements at the following time points: before CPB, five, 20, 40, 60 min on CPB, five minutes before end of CPB and ten minutes after CPB. Jugular bulb samples were taken at a rate of 0.5 ml•min–1 to avoid extracranial contamination.14
Statistical analysis
All results were analysed with SPSS version 7.5 for Windows. The Bland and Altman analysis with limits of agreement15 was used to study the agreement between the TOI and SjO2. We decided that ± 5% would be a clinically acceptable difference between the two methods (SjO2 and TOI) while still supporting the conclusion that the two methods are interchangeable.
Differences from baseline for SjO2, TOI were assessed by Wilcoxon signed rank test.
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Results |
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A total of 118-paired measurements of TOI and SjO2 were analysed. The mean difference (bias) between measurements was -6.7% (TOI - SjO2) with wide limits of agreement (15 to -28%), more than the chosen tolerable clinical difference (± 5%). Correlation between the two methods was poor (r2=0.166; Table
and Figure 1). When this variation was split into between-and within-patient measurements, Bland and Altman analysis for the means of the 17 cases also showed a bias of -6.74%, with limits of agreement that were closer, but still wider than acceptable (8 to -21%). Correlation between the two methods improved somewhat (r2=0.237; Table).
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), the bias between TOI and SjO2 was zero, with intermediate limits of agreement (± 16%). The correlation between the two methods was a little better than for all individual measurements (r2=0.132). We observed a statistically significant correlation between individual measurements of SjO2 and arterial carbon dioxide tension (PaCO2) (r2=0.333, P=0.0003). However, TOI did not correlate with PaCO2 (r2=0.001, P=0.7).
A few patients had one or two episodes of cerebral desaturation (50%), but no measurement was less than 44% and never were SjO2 and TOI both below 50%.
At each time point during and after CPB, the mean TOI is lower than the corresponding mean SjO2 (Figure 2). Mean TOI was significantly decreased during and after CPB, and mean SjO2 increased significantly at 20 and 40 min on CPB compared to pre-bypass levels (Figure 2). All patients made an uneventful recovery on the first post-operative day.
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Comparison of SjO2 and regional cerebral oxygen saturation measured by another NIRS machine (INVOS 3100®, Somanetics Inc., Troy, MI) has been performed.16–20 The design of the Somanetics device differs considerably from others. It has two receivers at different distances from the light emitter to correct for surface tissue overlying the brain. A single absolute value of regional cerebral oxygen saturation is calculated by an algorithm which is thought to be independent of path length.16–20
Daubeney et al.16 studied 29 children undergoing cardiac catheterization and 11 children during cardiac surgery. They found a significant correlation between the individual measurements (n=147) of the two methods (r2=0.476, P <0.0001) but the authors did not perform a Bland and Altman analysis. Although, Brown et al.17 reported a minimal bias of -0.46%, the limits of agreement between the two methods were considerable (~ ± 25%) during adult cardiac surgery, a finding consistent with our results. Furthermore, poor agreement between the two methods of cerebral oxygenation were detected in head injury patients18,19 as well as in patients resuscitated from cardiac arrest.20
Sapire et al.21 found a good correlation (r2=0.63, P <0.001) between the changes from baseline of SjO2 and regional oxygenation monitored by another NIRS (RunMan, NIM, Philadelphia, PA) device. Yet, correlation was poor in some patients, and in others, there was a delay between the two measurements.21 The authors also suggested that this time difference might be a result of the difference between regional oxygenation in the area of the brain monitored by NIRS and the global oxygen saturation measured by jugular bulb catheter.
Several factors may contribute to the observed lack of agreement. First, NIRS cerebral monitoring measures TOI in a small region of the cranial microvasculature, whereas SjO2 reflects a more global measurement. Thus, any inhomogeneous distribution of blood or metabolic activity will reduce the agreement between the two methods.17 Second, the actual TOI signal is the average of arterial (25%), capillary (5%) and venous blood (70%). In addition, contamination from the extracranial tissues may be a contributing factor.
TOI, which includes arteriolar blood, would normally be expected to be higher than SjO2. However, mean TOI was less than SjO2 both during and after CPB (Figure 2). This could be explained by higher SjO2 compared with TOI because jugular bulb saturation incorporates blood from deeper brain structures that extract less oxygen than the neocortex monitored by NIRS,22 or it could be due to the impact of extracranial tissue on NIRS signals.18–22
The suggestion that extracranial tissue makes a major contribution to NIRS signals has been extensively documented in theoretical and laboratory studies of light transport in a multi-layer media.23 These have been supported by clinical experimental data, which indicate that cerebral blood flow measured by NIRS is three times greater when the probe is placed on the dura than when it is measured through the scalp.24 More recently, Young et al.25 found that removal of skull bone and dura from the NIRS light path caused a significant reduction in detected intensity (up to 14-fold decrease). These authors suggested that the skull and/or its interface with other layers might act as an optical channel distorting the behaviour of NIRS light in the human head.
If the disagreement between TOI and SjO2 is due to regional desaturations, it could be assumed that SjO2 is less sensitive for detection of regional cerebral ischemia: whereas a normal SjO2 does not guarantee that there is no regional cerebral ischemia, a low SjO2 may be indicative of global or focal ischemia, or both.26
The lack of correlation between TOI and PaCO2 is consistent with the studies of Germon et al.22,27 Using another NIRS machine (INVOS 3100®) device, they were not able to detect changes in cerebral oxygenation as a result of cerebral hyperemia due to hypercapnia. By contrast, Tateishi et al.28 studied nine patients with head trauma and found that the direction and magnitude of changes in cerebral oxyhemoglobin concentration measured by NIRS and SjO2 in response to changes in PaCO2 were similar in eight of the patients. However, in one patient, despite an increase in SjO2 by 20% in response to increased PaCO2, the response of oxyhemoglobin was negligible. This might indicate a local difference in CO2 responsiveness.
Our results show that the two methods are not interchangeable. Which one is "right"remains a subject of controversy, since both methods probably measure different entities.
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Acknowledgments |
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Footnotes |
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Accepted for publication January 16, 2001.
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2 Croughwell ND, Newman MF, Blumenthal JA, et al. Jugular bulb saturation and cognitive dysfunction after cardiopulmonary bypass. Ann Thorac Surg 1994; 58:1702–8.[Abstract]
3 Croughwell ND, Frasco P, Blumenthal JA, Leone BJ, White WD, Reves JG. Warming during cardiopulmonary bypass is associated with jugular bulb desaturation. Ann Thorac Surg 1992; 53: 827–32.[Abstract]
4
Cook DJ, Oliver WC Jr, Orszulak TA, Daly RC. A prospective, randomized comparison of cerebral venous oxygen saturation during normothermic and hypothermic cardiopulmonary bypass. J Thorac Cardiovasc Surg 1994; 107: 1020–9.
5
Jöbsis FF. Noninvasive, infrared monitoring of cerebral and myocardial oxygen sufficiency and circulatory parameters. Science 1977; 198: 1264–7.
6 Nollert G, Shin’oka T, Jonas RA. Near-infrared spectrophotometry of the brain in cardiovascular surgery. Thorac Cardiovasc Surg 1998; 46: 167–75.[Medline]
7
Kurth CD, Steven JM, Nicolson SC, Jacobs ML. Cerebral oxygenation during cardiopulmonary bypass in children. J Thorac Cardiovasc Surg 1997; 113: 71–9.
8 Nollert G, Möhnle P, Tassani-Prell P, Reichart B. Determinants of cerebral oxygenation during cardiac surgery. Circulation 1995; 92(suppl II): II-327–II-33.
9 Rigg CD, Clutton-Brock TH. Near-infrared spectroscopy changes during hypothermic circulatory arrest with retrograde cerebral perfusion. Anaesthesia 1997; 52: 356–63.[Medline]
10 Fallon P, Roberts I Kirkham FJ, et al. Cerebral hemodynamics during cardiopulmonary bypass in children using near-infrared spectroscopy. Ann Thorac Surg 1993; 56: 1473–7.[Abstract]
11 Williams IM, Picton AJ, Hardy SC, Mortimer AJ, McCollum CN. Cerebral hypoxia detected by near infrared spectroscopy. Anaesthesia 1994; 49: 762–6.[Medline]
12 Kirkpatrick PJ, Smielewski P, Lam JMK, Al-Rawi P. Use of near infrared spectroscopy for the clinical monitoring of adult brain. J Biomed Opt 1996; 1: 363–72.
13
Owen-Reece H, Smith M, Elwell CE, Goldstone JC. Near infrared spectroscopy. Br J Anaesth 1999; 82: 418–26.
14 Matta BF, Lam AM. The rate of blood withdrawal affects the accuracy of jugular venous bulb. Oxygen saturation measurements. Anesthesiology 1997; 4: 806–8.
15 Bland JM, Altman DG. Statistical methods for assessing agreement of two methods of clinical measurement. Lancet 1986; 1: 307–10.[Medline]
16
Daubeney PEF, Pilkington SN, Janke E, Charlton GA, Smith DC, Webber SA. Cerebral oxygenation measured by near infrared spectroscopy: comparison with jugular bulb oximetry. Ann Thorac Surg 1996; 61: 930–4.
17 Brown R, Wright G, Royston D. A Comparison of two systems for assessing cerebral venous oxyhaemoglobin saturation during cardiopulmonary bypass in humans. Anaesthesia 1993; 48: 697–700.[Medline]
18 Lewis SB, Myburgh JA, Thornton EL, Reilly PL. Cerebral oxygenation monitoring by near-infrared spectroscopy is not clinically useful in patients with severe closed-head injury: a comparison with jugular venous bulb oximetry. Crit Care Med 1996; 24: 1334–8.[Medline]
19 Minassian AT, Poirier N, Pierrot M, et al. Correlation between cerebral oxygen saturation measured by near-infrared spectroscopy and jugular oxygen saturation in patients with severe closed head injury. Anesthesiology 1999; 91: 985–90.[Medline]
20 Buunk G, van der Hoeven JG, Meinders AE. A comparison of near-infrared spectroscopy and jugular bulb oximetry in comatose patients resuscitated from a cardiac arrest. Anaesthesia 1998; 53: 13–9.
21 Sapire KJ, Gopinath SP, Farhat G, et al. Cerebral oxygenation during warming after cardiopulmonary bypass. Crit Care Med 1997; 25: 1655–62.[Medline]
22 Germon TJ, Young AER, Manara AR, Nelson RJ. Extracerebral absorption of near infrared light influences the detection of increased cerebral oxygenation monitored by near infrared spectroscopy. J Neurol Neurosurg Psychiatry 1995; 58: 477–9.[Abstract]
23 Okada E, Firbank M, Delpy DT. The effect of overlying tissue on the spatial sensitivity profile of near- infrared spectroscopy. Phys Med Biol 1995; 40: 2093–108.[Medline]
24
Owen-Reece H, Elwell CE, Harkness W, et al. Use of near infrared spectroscopy to estimate cerebral blood flow in conscious and anaesthetized adult subjects. Br J Anaesth 1996; 76: 43–8.
25
Young AER, Germon TJ, Barnett NJ, Manara AR, Nelson RJ. Behaviour of near-infrared light in the adult human head: implications for clinical near-infrared spectroscopy. Br J Anaesth 2000; 84: 38–42.
26 Matta B. Advances in monitoring cerebral oxygenation. Curr Opin Anaesth 1996; 9: 365–70.
27
Germon T, Kane NM, Manara AR, Nelson RJ. Near infrared spectroscopy in adults: effects of extracranial ischemia and intracranial hypoxia on estimation of cerebral oxygenation. Br J Anaesth 1994; 73: 503–6.
28 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.[Medline]
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