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Effect of alpha-stat vs. pH-stat strategies on cerebral oximetry during moderate hypothermic cardiopulmonary bypass

Published online by Cambridge University Press:  07 July 2006

M. Nauphal ,
M. El-Khatib ,
S. Taha ,
S. Haroun-Bizri ,
M. Alameddine  and
A. Baraka
M. Nauphal
Affiliation:
American University of Beirut, Department of Anesthesiology, Beirut, Lebanon
M. El-Khatib
Affiliation:
American University of Beirut, Department of Anesthesiology, Beirut, Lebanon
S. Taha
Affiliation:
American University of Beirut, Department of Anesthesiology, Beirut, Lebanon
S. Haroun-Bizri
Affiliation:
American University of Beirut, Department of Anesthesiology, Beirut, Lebanon
M. Alameddine
Affiliation:
American University of Beirut, Department of Anesthesiology, Beirut, Lebanon
A. Baraka
Affiliation:
American University of Beirut, Department of Anesthesiology, Beirut, Lebanon
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Extract

Summary

Background and objectives: This study was undertaken to compare the effect of alpha-stat vs. pH-stat strategies for acid–base management on regional cerebral oxygen saturation (RsO2) in patients undergoing moderate hypothermic haemodilution cardiopulmonary bypass (CPB). Methods: In 14 adult patients undergoing elective coronary artery bypass grafting, an awake RsO2 baseline value was monitored using a cerebral oximeter (INVOS 5100). Cerebral oximetry was then monitored continuously following anaesthesia and during the whole period of CPB. Mean ± SD of RsO2, CO2, mean arterial pressure and haematocrit were determined before bypass and during the moderate hypothermic phase of the CPB using the alpha-stat followed by pH-stat strategies of acid–base management. Alpha-stat was then maintained throughout the whole period of CPB. Results: The mean baseline RsO2 in the awake patient breathing room air was 59.6 ± 5.3%. Following anaesthesia and ventilation with 100% oxygen, RsO2 increased up to 75.9 ± 6.7%. Going on bypass, RsO2 significantly decreased from a pre-bypass value of 75.9 ± 6.7% to 62.9 ± 6.3% during the initial phase of alpha-stat strategy. Shifting to pH-stat strategy resulted in a significant increase of RsO2 from 62.9 ± 6.3% to 72.1 ± 6.6%. Resuming the alpha-stat strategy resulted in a significant decrease of RsO2 to 62.9 ± 7.8% which was similar to the RsO2 value during the initial phase of alpha-stat. Conclusion: During moderate hypothermic haemodilutional CPB, the RsO2 was significantly higher during the pH-stat than during the alpha-stat strategy. However, the RsO2 during pH-stat management was significantly higher than the baseline RsO2 value in the awake patient breathing room air, denoting luxury cerebral perfusion. In contrast, the RsO2 during alpha-stat was only slightly higher than the baseline RsO2, suggesting that the alpha-stat strategy avoids luxury perfusion, but can maintain adequate cerebral oxygen supply-demand balance during moderate hypothermic haemodilutional CPB.

Keywords

OXIMETRY, cerebralCARDIOPULMONARY BYPASSCARDIAC SURGERYBLOOD GAS ANALYSIS, alpha-stat, pH-statHYPOTHERMIAHAEMODILUTION
Type
EACTA Original Article
Information
European Journal of Anaesthesiology , Volume 24 , Issue 1 , January 2007 , pp. 15 - 19
Copyright
© 2006 European Society of Anaesthesiology

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References

Murkin J. Con: blood gases should not be corrected for temperature during hypothermic cardiopulmonary bypass: α-stat mode. J Cardiothorac Anesth 1988; 2: 705–707.Google Scholar
Tinker JH, Campos JH. Pro: blood gases should be corrected for temperature during cardiopulmonary bypass: pH-stat mode. Cardiothorac Anesth 1988; 2: 701–704.Google Scholar
Rhan H. Body temperature and acid–base regulation. Pneumonologie 1974; 151: 87–94.Google Scholar
Ream AK, Reitz BA, Silverberg G. Temperature correction of PCO2 and pH in estimating acid–base status: an example of the emperor's new clothes? Anesthesiology 1982; 56: 41–44.Google Scholar
Murkin JM, Farrar JK, Tweed WA, McKenzie FN, Guiraudon G. Cerebral autoregulation and flow/metabolism coupling during cardiopulmonary bypass: the influence of PaCO2. Anesth Analg 1987; 66 (9): 825–832.Google Scholar
Yao FS, Tseng CC, Ho CY et al. Cerebral oxygen desaturation is associated with early postoperative neuropsychological dysfunction in patients undergoing cardiac surgery. J Cardiothorac Vasc Anesth 2004; 18 (5): 552–558.Google Scholar
O'Dwyer C, Porough D, Johnston W. Determinants of cerebral perfusion during cardiopulmonary bypass. J Cardiothorac Vasc Anesth 1996; 1: 54–65.Google Scholar
Holzschuh M, Woertgen C, Metz C, Brawanski A. Dynamic changes of cerebral oxygenation measured by brain tissue oxygen pressure and near infrared spectroscopy. Neurol Res 1997; 19: 246–248.Google Scholar
Edmonds HL, Rodriguez RA, Audenaert SM et al. The role of neuromonitoring in cardiovascular surgery. J Cardiothorac Vasc Anesth 1996; 10: 15–23.Google Scholar
Lozano S, Mossad E. Cerebral function monitors during pediatric cardiac surgery: can they make a difference. J Cardiothorac Vasc Anesth 2004; 18: 645–656.Google Scholar
Daubeney PE, Pilkington SN, Janke E et al. Cerebral oxygenation measured by near-infrared spectroscopy: comparison with jugular bulb oximetry. Ann Thorac Surg 1996; 61: 930–934.Google Scholar
Jobsis-Vander Vliet FF. Non-invasive, near-infrared monitoring of cellular sufficiency in vivo. Adv Exp Med Biol 1985; 191: 833–841.Google Scholar
Samra SK, Stanley JC, Zelenock GB et al. An assessment of contributions made by extracranial tissues during cerebral oximetry. J Neurosurg Anesth 1999; 11: 1–5.Google Scholar
Baraka A, Baroody M, Haroun S et al. Continuous venous oximetry during cardiopulmonary bypass: influence of temperature changes, perfusion flow, and hematocrit levels. J Cardiothorac Vasc Anesth 1990; 1 (4): 35–38.Google Scholar
Larach DR, High KM, Derr JA et al. Carbon dioxide elimination during total cardiopulmonary bypass in infants and children. Anesthesiology 1988; 69 (2): 185–191.Google Scholar
Duebener LF, Hagino I, Schmitt K et al. Effects of hemodilution and phenylephrine on cerebral blood flow and metabolism during cardiopulmonary bypass. J Cardiothorac Vasc Anesth 2004; 18: 423–428.Google Scholar