Cerebral Oxygen Monitoring during Neonatal
Cardiopulmonary Bypass and Deep Hypothermic Circulatory Arrest

Abstract

Background: This study was undertaken to investigate the physiological effects of cardiopulmonary bypass (CPB) and deep hypothermic circulatory arrest (DHCA) on cerebral oxygen metabolism estimated by near-infrared spectroscopy (NIRS). Methods: Ten newborn piglets (2.1 to 2.6 kg) were monitored with right frontal NIRS; the right jugular bulb was cannulated for intermittent sampling of jugular venous blood. All animals underwent CPB, cooling to a core temperature below 15° C, 60 minutes of DHCA followed by subsequent reperfusion and rewarming. Continuously recorded NIRS data and intermittent jugular venous blood values were compared. Results: NIRS performance was examined over the jugular venous oxygen saturation (SjvO₂) range of 40 to 98 %, a linear correlation was found between SjvO2 and NIRS-derived regional cerebral oxygen saturation (rSO₂) (r = 0.91, p < 0.001). A correlation was observed between the cellular oxidation NIRS-parameter cytochrome oxidase aa3 (CytOx) slope during the DHCA period in relation to rectal and nasopharyngeal temperature immediately before the onset of DHCA (r = 0.75 and 0.85, p < 0.001). Conclusions: This study suggests that NIRS-measured hemoglobin oxygenation parameters may reflect functional changes in cerebral hemodynamics and brain tissue oxygenation, while CytOx values represent related effects on intracellular oxidative metabolism.

Key words

Cerebral oxygen metabolism - Near-infrared spectroscopy - Cardio pulmonary bypass - Deep hypothermic circulatory arrest - Newborn piglets

References

• 1 Shoemaker W C. Oxygen transport and oxygen metabolism in shock and critical illness. Invasive and noninvasive monitoring of circulatory dysfunction and shock.  Crit Care Clin. 1996;  12 939-969
• 2 Jonas R A. Neurological protection during cardiopulmonary bypass/deep hypothermia.  Pediatr Cardiol. 1998;  19 321-330
• 3 Gruz J. The first decade of continuous monitoring of jugular bulb oxyhemoglobin saturation: management strategies and clinical outcome.  Crit Care Med. 1998;  26 344-351
• 4 Gopinath S P, Valadka A B, Uzura M, Robertson C S. Comparison of jugular venous oxygen saturation and brain tissue Po₂ as monitors of cerebral ischemia after head injury.  Crit Care Med. 1999;  27 2337-2345
• 5 Kern F H, Jonas R A, Mayer J E, Hanley F L, Castaneda A R, Hickey P R. Temperature monitoring during CPB in infants: Does it predict efficient brain cooling?.  Ann Thorac Surg. 1992;  54 749-754
• 6 McCullough J N, Zhang N, Reich D L. et al . Cerebral metabolic suppression during hypothermic circulatory arrest in humans.  Ann Thorac Surg. 1999;  67 1895-1899
• 7 Jöbsis F. Noninvasive, infrared monitoring of cerebral and myocardial oxygen sufficiency and circulatory parameters.  Science. 1977;  198 1264-1267
• 8 McCormick P W, Stewart M, Goetting M G, Balakrishnan G. Regional cerebrovascular oxygen saturation measured by optical spectroscopy in humans.  Stroke. 1991;  22 596-602
• 9 Brazy J E. Cerebral oxygen monitoring with near-infrared spectroscopy: Clinical application to neonates.  J Clin Monit. 1991;  7 325-334
• 10 Greeley W J, Bracey V A, Ungerleider R M. Recovery of cerebral metabolism and mitochondrial oxidation state is delayed after hypothermic circulatory arrest.  Circulation. 1991;  84 (Suppl. III) 400-406
• 11 Bucher H U. Detection of cellular hypoxia by monitoring cytochrome oxidase with near-infrared spectrophotometry. In: Ehrly AM, Fleckenstein W, Landgraf M., eds Clinical oxygen pressure measurement III. Berlin: Blackwell 1992: 15-24
• 12 Elwell C E, Owen-Reece H, Cope M, Wyatt J S, Edwards A D, Delpy D T, Reynolds E OR. Measurement of cerebral haemodynamics using near-infrared spectroscopy.  Acta Neurochir (Suppl). 1993;  59 74-80
• 13 du Plessis A J, Newburger J, Jonas R A. et al . Cerebral oxygen supply and utilization during infant cardiac surgery.  Ann Neurol. 1995;  37 488-497
• 14 Levy W J, Levin S, Chance B. Near-infrared measurement of cerebral oxygenation. Correlation with electroencephalographic ischemia during ventricular fibrillation.  Anesthesiology. 1995;  83 738-746
• 15 Kurth C D, Steven J M, Swedlow D. New frontiers in oximetry.  Am J Anesthesiol. 1996;  23 169-175
• 16 Abdul-Khaliq H, Troitzsch D, Berger F, Lange P E. Comparison of regional transcranial oximetry with near-infrared spectroscopy (NIRS) and jugular venous bulb saturation for the monitoring of cerebral oxygenation in infants and children.  Biomed Techn (Berl). 2000;  45 328-332
• 17 Wray S, Cope M, Deply D T, Wyatt J S, Reynolds E OR. Characterization of near infrared absorption spectra of cytochrome aa3 and haemoglobin for the non-invasive monitoring of cerebral oxygenation.  Biochim Biophys Acta. 1988;  933 184-192
• 18 Tsuji M, Naruse H, Volpe J, Holtzmann D. Reduction in cytochrome aa3 measured by near-infrared spectroscopy predicts cerebral energy loss in hypoxic piglets.  Pediatr Res. 1995 ;  37 253-259
• 19 Cooper C E, Cope M, Springett R. et al . Use of mitochondrial inhibitors to demonstrate that cytochrome oxidase near-infrared spectroscopy can measure mitochondrial dysfunction noninvasively in the brain.  J Cereb Blood Flow Metab. 1999;  19 27-38
• 20 Springett R, Newman J, Cope M, Delpy D T. Oxygen dependency and precision of cytochrome oxidase signal from full NIRS of the piglet brain.  Am J Physiol (Heart Circ Physiol). 2000;  279 H2202-H2209

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