Extração cerebral de oxigênio: um modelo prático e suas aplicações clínicas

Cruz, Julio

doi:10.1590/S0004-282X1997000100005

Resumos

A extração cerebral de oxigênio (ECO2) constitui uma medida fisiológica pratica, com múltiplas aplicações clínicas. Esta variável é calculada simplesmente como a diferença artério-jugular das saturações da oxi-hemoglobina (de sangue arterial e do bulbo jugular). Por se tratar de medida global, a ECO2 não permite detecção de alterações regionais do hemometabolismo cerebral. Todavia, sempre que se lidar com modificações predominantemente (não exclusivamente) globais, a ECO2 fornece informação fidedigna sobre o balanço (ou acoplamento) entre o consumo cerebral de oxigênio e o fluxo sangüíneo cerebral.

extração cerebral de oxigênio; hemometabolismo cerebral; oxigenação cerebral

Cerebral extraction of oxygen (CEO2) represents a practical physiologic measure, with multiple clinical applications. This variable is calculated as the arterio-jugular difference in oxyhemoglobin saturation (from arterial blood and from the jugular bulb). Because it involves global measurements, the CEO2 does not allow detection of regional abnormalities in cerebral hemometabolism. However, when dealing with predominantly (not exclusively) global changes, the CEO2 provides accurate information on the balance (or coupling) between cerebral consumption of oxygen and cerebral blood flow.

cerebral extraction of oxygen; cerebral hemometabolism; cerebral oxygenation

Extração cerebral de oxigênio: um modelo prático e suas aplicações clínicas

Cerebral extraction of oxygen: a practical model and its clinical applications

Julio Cruz

Associate Professor of Neurosurgery, Department of Neurosurgery, Allegheny University of the Health Sciences, Philadelphia, Pennsylvania, U.S.A.

RESUMO

A extração cerebral de oxigênio (ECO₂) constitui uma medida fisiológica pratica, com múltiplas aplicações clínicas. Esta variável é calculada simplesmente como a diferença artério-jugular das saturações da oxi-hemoglobina (de sangue arterial e do bulbo jugular). Por se tratar de medida global, a ECO₂ não permite detecção de alterações regionais do hemometabolismo cerebral. Todavia, sempre que se lidar com modificações predominantemente (não exclusivamente) globais, a ECO₂ fornece informação fidedigna sobre o balanço (ou acoplamento) entre o consumo cerebral de oxigênio e o fluxo sangüíneo cerebral.

Palavras-chave: extração cerebral de oxigênio, hemometabolismo cerebral, oxigenação cerebral.

ABSTRACT

Cerebral extraction of oxygen (CEO₂) represents a practical physiologic measure, with multiple clinical applications. This variable is calculated as the arterio-jugular difference in oxyhemoglobin saturation (from arterial blood and from the jugular bulb). Because it involves global measurements, the CEO₂ does not allow detection of regional abnormalities in cerebral hemometabolism. However, when dealing with predominantly (not exclusively) global changes, the CEO₂ provides accurate information on the balance (or coupling) between cerebral consumption of oxygen and cerebral blood flow.

Key words: cerebral extraction of oxygen, cerebral hemometabolism, cerebral oxygenation.

Texto completo disponível apenas em PDF.

Full text available only in PDF format.

AGRADECIMENTOS

O autor agradece muito a seus pais, Julio Adamor Cruz (in memoriam) e Hermendina Xavier Cruz, por 25 anos de apoio integral e inestimável durante o processo educacional; a Rotary Foundation of Rotary International, pela Bolsa de Pós-Graduação de um ano (1980-81) que lhe permitiu a adaptação inicial nos Estados Unidos; e aos médicos(as), enfermeiras(os), cientistas, e técnicos(as) que contribuíram para o desenvolvimento deste trabalho.

Aceite: 12-outubro-1996.

Julio Cruz,M.D.,Ph.D. - Department of Neurosurgery, Allegheny University - Broad & Vine, Mail Stop 455, Philadelphia, PA 19102-1192, USA. FAX: (1215) 762 3132.

1. Cruz J, Allen SJ, Miner ME. Hypoxic insults in acute brain injury (abstr). Crit Care Med 1985,13:284.
2. Cruz J, Miner ME, Allen SJ, Alves WM Gennarelli TA. Continuous monitoring of cerebral oxygenation in acute brain injury: injection of mannitol during hyperventilation. J Neurosurg 1990;73:725-730.
3. Cruz J, Gennarelli TA, Hoffstad OJ. Lack of relevance of the Bohr effect in optimally ventilated patients with acute brain trauma. J Trauma 1992;33:304-311.
4. Cruz J, Jaggi JL, Hoffstad OJ. Cerebral blood flow and oxygen consumption in acute brain injury with acute anemia: an alternative for the cerebral metabolic rate of oxygen consumption ? Crit Care Med 1993;21:1218-1224.
5. Cruz J. Combined continuous monitoring of systemic and cerebral oxygenation in acute brain injury: preliminary observations. Crit Care Med 1993;21:1225-1232.
6. Cruz J. An additional therapeutic effect of adequate hyperventilation in severe acute brain trauma: normalization of cerebral glucose uptake. J Neurosurg 1995;82:379-385.
7. Cruz J. Relationship between early patterns of cerebral extraction of oxygen and outcome from severe acute traumatic brain swelling: cerebral ischemia or cerebral viability ? Crit Care Med 1996;24:953-956.
8. Cruz J. Adverse effects of pentobarbital on cerebral venous oxygenadon of comatose patients with acute traumatic brain swelling: relationship to outcome. J Neurosurg 1996;85:758-761.
9. Gibbs EL, Lennox WG, Nims LF, Gibbs FA. Arterial and cerebral venous blood: arterial-venous differences in man. J Biol Chem 1942;144:325-332.
10. Kety SS, Schmidt CF. The nitrous oxide method for the quantitative determination of cerebral blood flow in man: theory, procedure, and normal values. J Clin Invest 1948;27:476-483.
11. Muizelaar JP, Marmarou A, Ward JD, Kontos HA, Choi SC, Becker DP, Gruemer H, Young HF. Adverse effects of prolonged hyperventilation in patients with severe head injury: a randomized clinical trial. J Neurosurg 1991 ;75:731 -739
12. Rosner MJ, Rosner SD, Johnson AH. Cerebral perfusion pressure: management protocol and clinical results. J Neurosurg 1995;83:949-962.
13. Uzzell BP, Obrist WD, Dolinskas CA, Langfitt WD. Relationship of acute CBF and ICP findings to neuropsychological outcome in severe head injury. J Neurosurg 1986;65:630-635

Datas de Publicação

Publicação nesta coleção
10 Nov 2010
Data do Fascículo
1997

This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.

[1] 1. Cruz J, Allen SJ, Miner ME. Hypoxic insults in acute brain injury (abstr). Crit Care Med 1985,13:284.

[2] 2. Cruz J, Miner ME, Allen SJ, Alves WM Gennarelli TA. Continuous monitoring of cerebral oxygenation in acute brain injury: injection of mannitol during hyperventilation. J Neurosurg 1990;73:725-730.

[3] 3. Cruz J, Gennarelli TA, Hoffstad OJ. Lack of relevance of the Bohr effect in optimally ventilated patients with acute brain trauma. J Trauma 1992;33:304-311.

[4] 4. Cruz J, Jaggi JL, Hoffstad OJ. Cerebral blood flow and oxygen consumption in acute brain injury with acute anemia: an alternative for the cerebral metabolic rate of oxygen consumption ? Crit Care Med 1993;21:1218-1224.

[5] 5. Cruz J. Combined continuous monitoring of systemic and cerebral oxygenation in acute brain injury: preliminary observations. Crit Care Med 1993;21:1225-1232.

[6] 6. Cruz J. An additional therapeutic effect of adequate hyperventilation in severe acute brain trauma: normalization of cerebral glucose uptake. J Neurosurg 1995;82:379-385.

[7] 7. Cruz J. Relationship between early patterns of cerebral extraction of oxygen and outcome from severe acute traumatic brain swelling: cerebral ischemia or cerebral viability ? Crit Care Med 1996;24:953-956.

[8] 8. Cruz J. Adverse effects of pentobarbital on cerebral venous oxygenadon of comatose patients with acute traumatic brain swelling: relationship to outcome. J Neurosurg 1996;85:758-761.

[9] 9. Gibbs EL, Lennox WG, Nims LF, Gibbs FA. Arterial and cerebral venous blood: arterial-venous differences in man. J Biol Chem 1942;144:325-332.

[10] 10. Kety SS, Schmidt CF. The nitrous oxide method for the quantitative determination of cerebral blood flow in man: theory, procedure, and normal values. J Clin Invest 1948;27:476-483.

[11] 11. Muizelaar JP, Marmarou A, Ward JD, Kontos HA, Choi SC, Becker DP, Gruemer H, Young HF. Adverse effects of prolonged hyperventilation in patients with severe head injury: a randomized clinical trial. J Neurosurg 1991 ;75:731 -739

[12] 12. Rosner MJ, Rosner SD, Johnson AH. Cerebral perfusion pressure: management protocol and clinical results. J Neurosurg 1995;83:949-962.

[13] 13. Uzzell BP, Obrist WD, Dolinskas CA, Langfitt WD. Relationship of acute CBF and ICP findings to neuropsychological outcome in severe head injury. J Neurosurg 1986;65:630-635

Brasil

Brasil

Extração cerebral de oxigênio: um modelo prático e suas aplicações clínicas

Cerebral extraction of oxygen: a practical model and its clinical applications

Resumos

Datas de Publicação