JTCS Speed Up Your Browser
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

This Article
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Add to Personal Folders
Right arrow Download to citation manager
Right arrow Permission Requests
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Miyamoto, T.-A.
Right arrow Articles by Miyamoto, K.-J.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Miyamoto, T.-A.
Right arrow Articles by Miyamoto, K.-J.

J Thorac Cardiovasc Surg 1999;118:569-570
© 1999 Mosby, Inc.

Letters to the Editor

Is alpha-stat management still justified for deep hypothermic circulatory arrest in adults?

Tadaomi-A. Miyamoto, MD

Research Department
Kokura Memorial Hospital
Kitakyushu, Japan

Koho-J. Miyamoto, MD, PhD

Assistant Professor
II Department of Physiology
University of the Ryukius
School of Medicine
Okinawa, Japan

To the Editor:

We read with great interest the article titled "Neuropsychologic Outcome After Deep Hypothermic Circulatory Arrest in Adults," by Reich and associates (J Thorac Cardiovasc Surg 199;117:156-63). The authors are to be congratulated for the timely and careful evaluation of deep hypothermic circulatory arrest (DHCA) as a means to protect the central nervous system (CNS) in adults after alpha-stat blood gas management.

Although alpha-stat blood gas management during perfusion hypothermia is widely accepted as the standard, pH-stat management is more physiologic, as observed phylogenically in nature. We would like to bring a few points to the attention of the readership:

The observed limit of 25 minutes as the dividing line between patients with and without sequelae seems to us too short, considering the rather low esophageal temperature of 12°C to 15°C. WeGo 1 studied a rabbit model of spinal cord ischemia for 60 minutes during surface-induced hypothermia managed according to pH-stat strategies. We observed that gross neurologic function can be consistently preserved at an esophageal temperature of 29.5°C. Even though CNS areas involved with neuropsychologic functions might be more vulnerable to ischemia than the spinal cord, the discrepancy seems to be out of proportion. Perfusion hypothermia for 60 minutes at 20°C under alpha-stat management without circulatory arrest followed by rewarming causes derangements in glucose use and decreased blood flow, which were attributed to rewarmingGo 2 but more likely were triggered by the hypothermia per se.Go 3 Such alterations may cause injury if long-lasting or severe enough, such as when circulatory arrest is superimposed. Whether pH-stat management would prevent those changes from occurring is not known, but the following observations are noteworthy:

  1. Although the major argument for using alpha-stat management during hypothermic perfusion in adults has been to avoid the so-called "luxury perfusion" of pH-stat strategies and the consequent increased likelihood of microembolization, pH-stat management for DHCA in children has been found to result in better neurologic outcome than alpha-stat strategies.Go 4 There are no reasons to believe that the outcome would be physiologically or metabolically any different in adults.
  2. The shift of the oxyhemoglobin dissociation curve to the left induced by the hypothermia-induced alkalosis is aggravated by the alpha-stat management. The increased affinity of hemoglobin to oxygen results in impairment of oxygen delivery, rendering the tissues hypoxic or anoxic despite adequate blood PO2.
  3. Alpha-stat management will result in extracellular alkalinity that has been found to exacerbate excitotoxic neuronal injury by sensitizing neurons to ischemic injury and to potentiate reperfusion injury.Go 5
  4. On the contrary, mild acidosis, which may be obtained by pH-stat management, decreases Ca++ influx by reducing N-methyl-D-aspartate receptor activation, glutamate neurotoxicity, and oxygen-glucose deprivation neuronal injury in cortical cultures,Go 6 as well as hippocampal neurons.Go 7
  5. In their study, all patients were given methylprednisolone (30 mg · kg–1) before undergoing DHCA. Although protective effects of methylprednisolone (30 mg · kg–1) given before ischemia were reported in 1983,Go 8 2 years later Sapolsky and Pulsinelli reported that even 10 mg · kg–1 of cortisone (glucocorticoids) potentiates ischemic injury to neurons.Go 9 To what extent and in which direction the methylprednisolone worked in patients undergoing DHCA is unknown. However, the possibility that the detrimental effect was the dominant effect cannot be ruled out when other conditions are taken into consideration simultaneously.

An equally careful prospective study using pH-stat management may result in longer than the 25-minute dividing time limits observed with alpha-stat strategies or may decrease the relative role of age as a risk factor. The long-debated issue of which blood gas management protocol is preferable during hypothermic perfusion needs to be resolved.

12/8/100286

References

  1. Miyamoto TA, Miyamoto KJ, Ohno N. Objective assessment of CNS function within 6 hours of spinal cord ischemia in rabbits. J Anesth 1998;12:189-94.
  2. Miyano H, Inagaki M, Hashimoto N, Shishido T, Kawada T, Miyake Y, et al. Regional cerebral blood flow during rewarming of cardiopulmonary bypass correlates with posthypothermic regional glucose use. J Thorac Cardiovasc Surg 1998;116:503-10.[Abstract/Free Full Text]
  3. Miyamoto TA, Miyamoto KJ. Regional cerebral blood flow and regional glucose use during rewarming after hypothermic cardiopulmonary bypass. J Thorac Cardiovasc Surg 1999;117:1228-9.[Free Full Text]
  4. du Plessis AJ, Jonas RA, Wypij D, Hickey PR, Riviello J, Wessel DL, et al. Perioperative effects of alpha-stat versus pH-stat strategies for deep hypothermic cardiopulmonary bypass in infants. J Thorac Cardiovasc Surg 1997;114:991-1001.[Abstract/Free Full Text]
  5. Giffard RG, Weiss JH, Choi DW. Extracellular alkalinity exacerbates injury of cultured cortical neurons. Stroke 1992;23:1817-21.[Abstract/Free Full Text]
  6. Giffard RG, Monyer H, Christine CW, Choi DW. Acidosis reduces NMDA receptor activation, glutamate neurotoxicity, and oxygen-glucose deprivation neuronal injury in cortical cultures. Brain Res 1990;506:339-42.[Medline]
  7. Tombaugh GC, Sapolsky RM. Mild acidosis protects hippocampal neurons from injury induced by oxygen and glucose deprivation. Brain Res 1990;506:343-5.[Medline]
  8. Taylor MD, Palmer GC, Callahan AS III. Protective action by methylprednisolone, allopurinol and indomethacin against stroke-induced damage to adenylate cyclase in gerbil cortex. Stroke 1983;15:329-35.[Abstract/Free Full Text]
  9. Sapolsky RM, Pulsinelli WA. Glucocorticoids potentiate ischemic injury to neurons: therapeutic implications. Science 1985;229:1397-400.[Abstract/Free Full Text]



This article has been cited by other articles:


Home page
 Asian Cardiovasc. Thorac. Ann.Home page
Y. Yang, Z. Li, L. Yang, M. Jackson, A. Turner, and J. Ye
Effect of pH Management on Brain Perfusion During Retrograde Cerebral Perfusion
Asian Cardiovasc Thorac Ann, December 1, 2006; 14(6): 495 - 500.
[Abstract] [Full Text] [PDF]

Home page
 Ann. Thorac. Surg.Home page
J. Ye, Z. Li, Y. Yang, L. Yang, A. Turner, M. Jackson, and R. Deslauriers
Use of a pH-stat strategy during retrograde cerebral perfusion improves cerebral perfusion and tissue oxygenation
Ann. Thorac. Surg., May 1, 2004; 77(5): 1664 - 1670.
[Abstract] [Full Text] [PDF]

This Article
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Add to Personal Folders
Right arrow Download to citation manager
Right arrow Permission Requests
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Miyamoto, T.-A.
Right arrow Articles by Miyamoto, K.-J.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Miyamoto, T.-A.
Right arrow Articles by Miyamoto, K.-J.

HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
ANN THORAC SURG ASIAN CARDIOVASC THORAC ANN EUR J CARDIOTHORAC SURG
J THORAC CARDIOVASC SURG ICVTS ALL CTSNet JOURNALS