JOURNAL HOME CME HOME THIS MONTH PAST ISSUES ETOC COLLECTIONS AUTHORS REVIEWERS EDITORIAL BOARD FEEDBACK RSS HELP
		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Abstract Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a colleague Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via ISI Web of Science (24) Citing Articles via Google Scholar Google Scholar Articles by Yoshitani, K. Articles by Furuya, H. Search for Related Content PubMed PubMed Citation Articles by Yoshitani, K. Articles by Furuya, H. Related Collections Monitoring (Non-cardiac) Technology

---

TECHNOLOGY, COMPUTING, AND SIMULATION

A Comparison of the INVOS 4100 and the NIRO 300 Near-Infrared Spectrophotometers

Kenji Yoshitani, MD^*, Masahiko Kawaguchi, MD^*, Kazuyuki Tatsumi, MD, Katsuyasu Kitaguchi, MD^*, and Hitoshi Furuya, MD^*

*Department of Anesthesiology, Nara Medical University, Nara, Japan; and Department of Anesthesia, Seikeikai Hospital, Osaka, Japan

Address correspondence and reprint requests to Kenji Yoshitani, MD, Department of Anesthesiology, Nara Medical University, 840 Shijo-cho, Kashihara, Nara 634-8522, Japan. Address e-mail to nkenji{at}mva.biglobe.ne.jp

	Abstract

Top Abstract Introduction Methods Results Discussion References

 
We determined whether two different devices for measuring near-infrared spectroscopy (NIRS)—the INVOS 4100 and the NIRO 300—produce similar cerebral oxygenation data during the CO₂ challenge test. Nineteen patients anesthetized with sevoflurane, 67% nitrous oxide in oxygen, and fentanyl were studied. A series of measurements of regional cerebral oxygen saturation (rSO₂), measured by the INVOS 4100, and tissue oxygen index (TOI), measured by the NIRO 300, were performed in the following conditions: 1) normocapnia (PaCO₂, 35–45 mm Hg); 2) hypocapnia (PaCO₂, 25–35 mm Hg); 3) normocapnia; and 4) hypercapnia (PaCO₂, 45–55 mm Hg). Hemodynamic variables, including arterial blood gases and cerebral blood flow velocity, were measured at the same time with transcranial Doppler. The values and percentage changes of rSO₂ and TOI were compared by using regression analysis and Bland and Altman analysis. The rSO₂ showed a significant positive correlation with TOI (r = 0.58, P < 0.01). The percentage change of rSO₂ also showed a significant positive correlation with the percentage change of TOI during the CO₂ challenge (r = 0.85, P < 0.01). Bland and Altman analysis revealed a bias of -0.5% with 2 SD of 15.6% when comparing the rSO₂ value with the TOI value, and it showed a bias of -3.4% with 2 SD of 15.2% when comparing the percentage change of rSO₂ with the percentage change of TOI, indicating unacceptable disagreement of these data. These results indicate that cerebral oxygen saturation and its relative change during the CO₂ challenge may vary depending on the type of NIRS used. Because the measurement technique and algorithm were different in each device, we should carefully consider the clinical application of the values produced by NIRS.

IMPLICATIONS: Near-infrared spectroscopy (NIRS) has been proposed as a noninvasive clinical method for assessing cerebral oxygenation. The acceptable reliability and validity of NIRS values have not been established despite their widespread use. The INVOS 4100 and the NIRO 300 can display cerebral oxygen saturation as regional cerebral oxygen saturation and tissue oxygenation index, but they produce differing results.

	Introduction

Top Abstract Introduction Methods Results Discussion References

 
Cerebral oximetry is a method of measuring brain tissue oxygen saturation noninvasively by near-infrared spectroscopy (NIRS), the data from which may be important clinically. This technique has been validated in clinical studies, as well as in experimental animals (1–3). However, doubts have been expressed concerning the accuracy of the measured values. Because there is no "gold standard," validation of the values has been difficult. Several investigators have suggested that cerebral oximetry by NIRS is affected significantly by changes in extracranial blood flow, despite the capacity of detecting tissue hypoxia deep in the scalp (4–6). Furthermore, there are a variety of commercially available NIRS instruments for clinical use. They use different technologies and methods to provide cerebral oxygenation data. Although previous studies have tried to compare various instruments, an appropriate analysis has not been used to assess the degree of agreement among these devices (7–9). There seems to be little agreement, for example, as to how to establish the criteria of cerebral oxygenation for each device. Currently at least two commercially available instruments—the INVOS 4100 (Somanetics, Troy, MI) and the NIRO 300 (Hamamatsu Photonics, Hamamatsu, Japan)—can display cerebral oxygen saturation. To determine whether these two devices produce similar cerebral oxygen saturation data, we compared the values obtained by these two instruments during the fluctuation of cerebral blood flow induced by CO₂ challenge tests.

	Methods

Top Abstract Introduction Methods Results Discussion References

 
Nineteen patients (7 women and 12 men, aged 22 to 76 yr) scheduled for elective orthopedic or gynecologic surgery during general anesthesia were enrolled in the study. After institutional approval, informed consent was obtained from each patient. Patients with a history of cerebrovascular disease were excluded. No preanesthetic medication was administered. Anesthesia was induced with fentanyl 4 µg/kg IV, propofol 2 mg/kg IV, and vecuronium 0.2 mg/kg IV, and the trachea was intubated. The lungs were mechanically ventilated to maintain PaCO₂ between 35 and 45 mm Hg. Anesthesia was maintained with 1% sevoflurane and 67% nitrous oxide in oxygen. The usual monitoring equipment was used, including a radial artery catheter for direct arterial blood pressure measurement and a nasopharyngeal thermistor for monitoring body temperature, which was maintained between 35.5°C and 36.5°C by using a warming blanket.

Regional cerebral oxygen saturation (rSO₂) and tissue oxygen index (TOI) were measured with the INVOS 4100 and the NIRO 300, respectively. For the measurement of rSO₂, the cerebral oximeter probe was placed on the right forehead, with the caudal border approximately 1 cm above the eyebrow and the medial edge at the midline. The INVOS 4100 uses two wavelengths of near-infrared light (730 and 810 nm) and measures the ratio of oxyhemoglobin (HbO₂) to total hemoglobin (HbT), which is a percentage value of rSO₂. The sensor contains a light-emitting diode (LED) and two detectors located 30 and 40 mm from the LED, allowing removal of the extracranial contribution of scattered light by the application of a subtraction algorithm. The proximal detector receives less of a signal from deeper brain tissue, whereas the distal detector measures the saturation of all of the tissue, including skin, muscle tissue, skull, and brain. If the signal detected by the proximal detector is subtracted from that of the distal detector, the ratio of the two can give a mean value for cerebral saturation.

The NIRO 300 monitor uses four wavelengths of near-infrared right (775, 825, 850, and 904 nm), and the sensor contains a laser diode and three detectors placed at 4 or 5 cm from the source of emitting light. It can measure a TOI (%), which is the ratio of HbO₂ to HbT. The NIRO 500, the earlier model of the NIRO 300, monitored only changes in Hb concentration and the redox state of cytochrome oxydase with a modified Beer-Lambert equation (10). Furthermore, the NIRO-300 uses the specially resolved spectrometer (SRS), which combines the multidistance measurements of optical attenuation and makes it possible to calculate the absolute concentration of HbO₂ and Hb in the tissue. Then, the TOI (%) is rapidly calculated. In contrast with the modified Beer-Lambert equation, the values derived by SRS are not affected by differential path-length factors.

A 2-MHz pulsed Doppler ultrasound device (Companion TCD System; EME, Überlingen, Germany) was used for transcranial measurements of blood flow velocity of the right middle cerebral artery (MCA). Insonation of the MCA was initiated at a depth of 45 mm. Confirmation of MCA identity was achieved by increasing insonation depth to visualization of the bidirectional flow pattern typical of the bifurcation of the internal carotid artery into the MCA and anterior cerebral artery. After individual adjustment of Doppler variables such as gain, sample volume, and power of ultrasound, the probe was handheld and fixed during the measurement.

At least 15 min after the beginning of surgery, during which stable hemodynamic variables were maintained, a series of measurements of rSO₂ and TOI were performed at the following points after an accommodation period of approximately 15 min: 1) during normocapnia (PaCO₂, 35–45 mm Hg) (the sensor of the INVOS 4100 was placed on the right forehead, and rSO₂ was measured 5 min after the attachment; just after the measurement of rSO₂, the sensor of the NIRO 300 was replaced on the same place and TOI was measured); 2) during hypocapnia (PaCO₂, 25–35 mm Hg) induced by adjusting the respiratory rate (TOI was measured with the sensor of the NIRO 300 as it was during normocapnia; the sensor of the INOVS 4100 was then replaced, and rSO₂ was measured 5 min after the attachment); 3) during normocapnia (PaCO₂, 35–45 mm Hg) (rSO₂ was measured with the sensor of the INVOS 4100 as it was during hypocapnia, and TOI was measured similarly with the replaced sensor of the NIRO 300); and 4) during hypercapnia (PaCO₂, 45–55 mm Hg) induced by adjusting the respiratory rate (TOI was measured, and then rSO₂ was similarly measured). Hemodynamic variables, including arterial blood gases and the mean blood flow velocity of the MCA, were also measured at a midpoint of each period.

Data were expressed as mean ± SD. Hemodynamic data were analyzed by one-way analysis of variance for repeated measures. The Bonferroni test was used for post hoc pairwise comparisons. The values and percentage changes in measured rSO₂ and TOI were compared by using regression analysis. The analysis of agreement is based on the methods proposed by Bland and Altman (11). These assess the extent of the agreement between two different methods of clinical measurements by calculating the mean of the differences between the values obtained by the two methods: bias and the SD of the differences.

	Results

Top Abstract Introduction Methods Results Discussion References

 
Mean arterial pressure, heart rate, body temperature, and Hb remained unchanged during the period of CO₂ challenge tests (Table 1). The values of TOI and rSO₂ and the percentage values of TOI and rSO₂ of control were similar during hypocapnia (Table 2). In contrast, during hypercapnia, percentage values of TOI of control were significantly lower than percentage values of rSO₂ (P < 0.05). The blood flow velocity of MCA significantly decreased during hypocapnia and increased during hypercapnia compared with normocapnia (P < 0.05). There was a significant positive correlation between the values of TOI and rSO₂ (r = 0.58, P < 0.01) and between the percentage values of TOI and rSO₂ of control (r = 0.85, P < 0.01) (Figs. 1 and 2).

View larger version (15K): [in this window] [in a new window]   Figure 1. A, Plot of regional cerebral oxygen saturation (rSO2) against tissue oxygen index (TOI) with the regression line; rSO2 and TOI values are significantly correlated with a regression equation. B, Plot of percentage changes of rSO2 against percentage change of TOI with the regression line; percentage change of rSO2 and TOI values are significantly correlated with a regression equation.

View larger version (17K): [in this window] [in a new window]   Figure 2. A, Plot of the error (regional cerebral oxygen saturation [rSO2] - tissue oxygen index [TOI]) against the mean of the rSO2 and TOI by using the method of Bland and Altman. The plot indicates that the rSO2 and the TOI are not closely associated because the limits of agreement are wide clinically. Precision was defined as 2 SD about the mean error (the bias). B, Plot of error (percentage change of rSO2 - percentage change of TOI) against the mean of the percentage change of rSO2 and percentage change of TOI by using the method of Bland and Altman. The plot indicates that the percentage change of rSO2 and the percentage change of TOI are not closely associated because the limits of agreement are wide clinically. Precision was defined as 2 SD about the mean error (the bias).

	Discussion

Top Abstract Introduction Methods Results Discussion References

 
NIRS is a method of continuous noninvasive monitoring of cerebral oxygenation (12,13). Previous studies of commercially available devices for clinical use mainly compared the INOVS 3100 and the NIRO 500. The INVOS 3100, approved by the United States Food and Drug Administration, displays rSO₂ directly. The NIRO 500 displays a change in HbT concentration and HbO₂ concentration and does not show the percentage value. It was difficult to compare the two apparatuses directly. Several studies (8,9) processed the NIRO 500 data to derive rSO₂ to compare the INVOS 3100 and the NIRO 500. The NIRO 500 measures the degree of change of HbO₂ concentration from an unknown baseline. On the other hand, the INOVS 3100 measures the ratio of HbO₂ to HbT at one time, not the degree of change. The comparison would not have been made accurately in the previous studies. The NIRO 300, which uses a new NIRS method of SRS, provides a TOI as a percentage value in rSO₂ in addition to the originally measured values of the NIRO 500. TOI is an absolute one-time value and is not the degree of the change. TOI, therefore, leads to a more accurate comparison among the INVOS 4100, the new model of the INVOS 3100, and the NIRO 300.

The results of this study showed that there was a good correlation between the values of rSO₂ and TOI and the percentage changes of rSO₂ and TOI during the CO₂ challenge test. However, Bland and Altman analysis revealed an unacceptable disagreement between the INVOS 4100 and the NIRO 300 during the CO₂ challenge test. A good correlation does not necessarily show an agreement between the values and their relative changes with the INVOS 4100 and the NIRO 300, but it indicates that their values change proportionally during the CO₂ challenge test (10). Although these instruments could measure CO₂-induced cerebrovascular reactivity individually (14,15), it seems likely that their values were not equivalent. The disagreement of measured data between the INVOS 4100 and the NIRO 300 can probably be explained by several factors. First, there is a difference in technical method between the INVOS 4100 and the NIRO 300. The INVOS 4100 measures the ratio of light absorption of HbO₂ and HbT and calculates a value for the mean cerebral saturation, avoiding quantification of change in Hb concentration. Servic et al. (16) described a method for determining the ratio of the absorption coefficients by using two wavelengths first. A further variant of this type of instrument is the INVOS 4100. However, the NIRO 300 provides an absolute measurement of tissue Hb concentration by using the SRS method. The multidistance approach of four wavelengths brings about an absolute measurement of cerebral Hb oxygen saturation. The difference of the two devices might create the discrepancy between the measured values. Second, the effect of extracranial blood flow on rSO₂ varies with the circumstances. Germon et al. (5) demonstrated that the INVOS 3100 cerebral oximeter was affected significantly by changes in extracranial blood flow oxygenation, which may affect its reliability in clinical practice. However, Cho et al. (6) reported that the responses to CO₂ change of the NIRO 500 tended to be greater than those of the INVOS 3100. They suggested that the subtraction method of the INVOS 3100 that effectively removes contamination by skin and bone leads to the fewer responses of the NIRO 500. Although the effect of extracranial blood flow on the data is still controversial (17), this might lead to the difference between the two devices. Third, instruments using LEDs as light sources, such as the INVOS, are more prone to error because the broad emission bandwidth (30 to 40 nm) means that an average extinction over this range must be used in the calculation. On the other hand, the laser diodes used in the NIRO 300 have a narrow emission wavelength that is only a few nanometers wide (12). This might affect the measured values of the two devices. The sensors for the INVOS 3100 and the NIRO 500 were placed on opposite sides at the same time in previous studies (7–9). The emerging light from the sources of the INVOS 3100 with wide bandwidth may interfere with the emerging light of the NIRO 500. Al-Rawi et al. (18) indicated that the NIRO 300 detector connection to the patient, being of a low voltage, was more prone to electrical interference from other monitoring equipment. The intensity of the emerging light would not be detected accurately. Therefore, we did not attach the sensors of these devices on opposite sides in this study.

NIRS methods in reflectance mode were accompanied by a path-length factor. The modified Beer-Lambert method used by the INVOS 4100 first needs to estimate path length. This factor appears in both the numerator and denominator of the ratio and cancels itself out, so that rSO₂ is considered not to be affected by the path-length factor. In the SRS method used by the NIRO 300, multidistance measurements of optical attenuation make it possible to be free from the path-length factor. The NIRO 500—a previous model of the NIRO 300—was limited in clinical use by the path-length factor and measured only the changes in Hb concentration from an unknown baseline. The SRS method makes it possible to quantify the absolute concentration of oxy- and deoxyhemoglobin and to calculate TOI. Although the measured values of the INVOS 4100 and the NIRO 300 may not be affected by path length, the difference of calculation method between the two devices might explain the discrepancy of measured values.

In this study, to exclude the effect of interference by the emerging light of the INVOS 4100 and to measure rSO₂ and TOI at the same side, the sensor of the INVOS 4100 was replaced with the NIRO 300 sensor. Therefore, the measured values of the INVOS 4100 and the NIRO 300 might be influenced by the replacement of the sensor, although it was replaced at the same site by marking the position. However, there were no significant differences between the measured values at first and second normocapnia. Furthermore, in several cases, after the last measurement of hypercapnia, patients were returned to normocapnia and the rSO₂ was measured. There were no significant differences among the values at the three time points of normocapnia. Therefore, we believe that the influence of sensor replacement on the results would be small.

In summary, we compared the INVOS 4100 and the NIRO 300 in detecting cerebrovascular CO₂ reactivity. The INVOS 4100 and the NIRO 300 showed a significant linear relation between the values of rSO₂ and TOI in response to CO₂ alteration. However, Bland and Altman analysis revealed that the individual values and the relative changes of the two apparatuses were not equivalent. These findings suggest that the degree of reduction of these values in response to improper oxygenation may differ depending on the device used. Although little is known about the ability of rSO₂ to detect dangerous levels of desaturation in a clinical setting, we may need to determine it for each device.

	Acknowledgments

 
The authors thank Professor Norio Kurumatani, Department of Hygiene, Nara Medical University, for his assistance in statistical analysis and preparing the manuscript.

	References

Top Abstract Introduction Methods Results Discussion References

 

1. Jobsis FF. Noninvasive infrared monitoring of cerebral and myocardial oxygen sufficiency and circulatory parameters. Science 1977; 198: 1264–7.[Abstract/Free Full Text]
2. Brazy JE, Lewis DV, Mitnick MH, et al. Noninvasive monitoring of cerebral oxygenation in preterm infants: preliminary observations. Pediatrics 1985; 75: 217–25.[Abstract/Free Full Text]
3. Wyatt JS, Cope M, Delpy DT, et al. Measurement of optical pathlength for cerebral near infrared spectroscopy in newborn infants. Dev Neurosci 1990; 12: 140–4.[ISI][Medline]
4. Harris DNF, Bailey SM. Near infrared spectroscopy in adults. Anaesthesia 1993; 48: 694–6.[ISI][Medline]
5. Germon TJ, Kane NM, Manara AR, et al. Near-infrared spectroscopy in adults: effects of extracranial ischaemia and intracranial hypoxia on estimation of cerebral oxygenation. Br J Anaesth 1994; 73: 503–6.[Abstract/Free Full Text]
6. Cho H, Nemoto EM, Yonas H, et al. Cerebral monitoring by means of oximetry and somatosensory evoked potentials during carotid endarterectomy. J Neurosurg 1998; 89: 533–8.[ISI][Medline]
7. Cho H, Nemoto EM, Sanders M, et al. Comparison of two commercially available near-infrared spectroscopy instruments for cerebral oximetry. J Neurosurg 2000; 93: 351–4.[ISI][Medline]
8. Grubhofer G, Tonninger W, Keznickl P, et al. A comparison of the monitors INVOS 3100 and NIRO 500 in detecting changes in cerebral oxygenation. Acta Anaesthesiol Scand 1999; 43: 470–5.[ISI][Medline]
9. Gomersall CD, Leung PL, Gin T, et al. A comparison of the Hamamatsu NIRO 500 and the INVOS 3100 near-infrared spectrophotometers. Anaesth Intensive Care 1998; 26: 548–57.[ISI][Medline]
10. Corp M, Delpy DT. A system for long-term measurement of cerebral blood and tissue oxygenation in newborn infants by near-infrared transillumination. Med Biol Eng Comput 1998; 26: 289–4.
11. Bland JM, Altman DG. Statistical methods for assessing agreement between two methods of clinical measurement. Lancet 1986; 1: 307–10.[ISI][Medline]
12. Wahr JA, Tremper KK, Samra S, et al. Near-infrared spectroscopy: theory and applications. J Cardiovasc Anesth 1996; 10: 406–18.
13. Owen-Reece H, Elwell CE, Harkness W, et al. Use of near infrared spectroscopy to estimate cerebral blood flow in conscious and anesthetized adult subjects. Br J Anaesth 1996; 76: 43–8.[Abstract/Free Full Text]
14. Smielewski P, Kirkpatrick P, Minhas P, et al. Can cerebrovascular reactivity be measured with near-infrared spectroscopy? Stroke 1995; 26: 2285–92.[Abstract/Free Full Text]
15. Terborg C, Gora F, Weiller C, et al. Reduced vasomotor reactivity in cerebral microangiopathy: a study with near-infrared spectroscopy and transcranial Doppler sonography. Stroke 2000; 31: 924–9.[Abstract/Free Full Text]
16. Servic E, Chance B, Leigh J, et al. Quantitation of time and frequency resolved optical spectra for the determination of tissue oxygenation. Anal Biochem 1991; 195: 330–51.[ISI][Medline]
17. Edwards AD, Richardson C, Van Der Zee P, et al. Measurement of hemoglobin flow and blood flow by near-infrared spectroscopy. J Appl Physiol 1993; 74: 1884–9.
18. Al-Rawi PG, Smielewski P, Hobbiger H, et al. Assessment of spatially resolved spectroscopy during cardiopulmonary bypass. J Biomed Opt 1999; 4: 208–16.

This article has been cited by other articles:

				A. Farouk, M. Karimi, M. Henderson, J. Ostrowsky, E. Siwik, and H. Hennein Cerebral regional oxygenation during aortic coarctation repair in pediatric population. Eur. J. Cardiothorac. Surg., July 1, 2008; 34(1): 26 - 31. [Abstract] [Full Text] [PDF]

				S. J. Howell Carotid endarterectomy Br. J. Anaesth., July 1, 2007; 99(1): 119 - 131. [Abstract] [Full Text] [PDF]

				J. D. Tobias Cerebral Oximetry Monitoring Provides Early Warning of Hypercyanotic Spells in an Infant with Tetralogy of Fallot J Intensive Care Med, March 1, 2007; 22(2): 118 - 120. [Abstract] [PDF]

				P. G. Al-Rawi and P. J. Kirkpatrick Tissue Oxygen Index: Thresholds for Cerebral Ischemia Using Near-Infrared Spectroscopy Stroke, November 1, 2006; 37(11): 2720 - 2725. [Abstract] [Full Text] [PDF]

				B. D. Kussman, D. Wypij, J. A. DiNardo, J. Newburger, R. A. Jonas, J. Bartlett, E. McGrath, and P. C. Laussen An Evaluation of Bilateral Monitoring of Cerebral Oxygen Saturation During Pediatric Cardiac Surgery Anesth. Analg., November 1, 2005; 101(5): 1294 - 1300. [Abstract] [Full Text] [PDF]

				K. Yoshitani, M. Kawaguchi, M. Iwata, N. Sasaoka, S. Inoue, N. Kurumatani, and H. Furuya Comparison of changes in jugular venous bulb oxygen saturation and cerebral oxygen saturation during variations of haemoglobin concentration under propofol and sevoflurane anaesthesia Br. J. Anaesth., March 1, 2005; 94(3): 341 - 346. [Abstract] [Full Text] [PDF]

				D. B. Andropoulos, S. A. Stayer, L. K. Diaz, and C. Ramamoorthy Neurological Monitoring for Congenital Heart Surgery Anesth. Analg., November 1, 2004; 99(5): 1365 - 1375. [Abstract] [Full Text] [PDF]

				D. B. Andropoulos, L. K. Diaz, C. D. Fraser Jr., E. D. McKenzie, and S. A. Stayer Is Bilateral Monitoring of Cerebral Oxygen Saturation Necessary During Neonatal Aortic Arch Reconstruction? Anesth. Analg., May 1, 2004; 98(5): 1267 - 1272. [Abstract] [Full Text] [PDF]

				D. B. Andropoulos, S. A. Stayer, E. D. McKenzie, and C. D. Fraser Jr Regional low-flow perfusion provides comparable blood flow and oxygenation to both cerebral hemispheres during neonatal aortic arch reconstruction J. Thorac. Cardiovasc. Surg., December 1, 2003; 126(6): 1712 - 1717. [Abstract] [Full Text] [PDF]

				N. Nagdyman, T. P. K. Fleck, P. Ewert, H. Abdul-Khaliq, M. Redlin, and P. E. Lange Cerebral oxygenation measured by near-infrared spectroscopy during circulatory arrest and cardiopulmonary resuscitation Br. J. Anaesth., September 1, 2003; 91(3): 438 - 442. [Abstract] [Full Text] [PDF]

				D. B. Andropoulos, S. A. Stayer, E. D. McKenzie, and C. D. Fraser Jr Novel cerebral physiologic monitoring to guide low-flow cerebral perfusion during neonatal aortic arch reconstruction J. Thorac. Cardiovasc. Surg., March 1, 2003; 125(3): 491 - 499. [Abstract] [Full Text] [PDF]

This Article Abstract Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a colleague Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via ISI Web of Science (24) Citing Articles via Google Scholar Google Scholar Articles by Yoshitani, K. Articles by Furuya, H. Search for Related Content PubMed PubMed Citation Articles by Yoshitani, K. Articles by Furuya, H. Related Collections Monitoring (Non-cardiac) Technology

Anesthesia & Analgesia® is published for the International Anesthesia Research Society® by Lippincott Williams & Wilkins with the assistance of Stanford University Libraries' HighWire Press®. Copyright 2006 by the International Anesthesia Research Society. Online ISSN: 1526-7598   Print ISSN: 0003-2999