Cerebrovascular responsiveness to CO2 in Haemophilus influenzae type b meningitis in rabbits
| Autor: | Ivor David Berkowitz, David A. Wilson, Anthony J. Slater, Richard J. Traystman |
|---|---|
| Rok vydání: | 1994 |
| Předmět: |
Male
medicine.medical_specialty Physiology medicine.medical_treatment Blood Pressure Inflammation Oxygen Consumption Hypocapnia Reference Values Physiology (medical) Internal medicine medicine Animals Normocapnia Cerebral perfusion pressure Saline Meningitis Haemophilus business.industry Brain Carbon Dioxide medicine.disease Haemophilus influenzae Endocrinology Cerebral blood flow Organ Specificity Regional Blood Flow Cerebrovascular Circulation Anesthesia Rabbits medicine.symptom Cardiology and Cardiovascular Medicine business Meningitis Hypercapnia circulatory and respiratory physiology |
| Zdroj: | American Journal of Physiology-Heart and Circulatory Physiology. 266:H1755-H1761 |
| ISSN: | 1522-1539 0363-6135 |
| DOI: | 10.1152/ajpheart.1994.266.5.h1755 |
| Popis: | The effect of experimental meningitis on regional cerebral blood flow (rCBF), cerebral metabolic rate for oxygen (CMRO2), and cerebrovascular responsiveness to CO2 was determined in pentobarbital-anesthetized rabbits. The animals were inoculated intracisternally with saline (control) or log-phase Haemophilus influenzae type b (Hib). Eighteen hours later rCBF was determined with radiolabeled microspheres at normocapnia, hypocapnia, and hypercapnia. Cerebrovascular responses to hypocapnia and hypercapnia were assessed by calculating the change in cerebrovascular resistance per millimeter mercury change in PaCO2. At all CO2 levels, meningitis (M) was associated with elevated CBF compared with control (C: 47.5 +/- 3.0, M: 60.9 +/- 4.5 ml.100 g-1.min-1 at normocapnia, P < 0.01). Regional differences were present. In forebrain, the hyperemia in meningitis was confined to the superficial cortical grey matter. When compared with control, meningitis was not associated with altered vasoreactivity during hypocapnia (C: -0.026 +/- 0.006, M: -0.026 +/- 0.008 mmHg.ml-1 x 100 g-1.min-1.mmHg PaCO2(-1)) or hypercapnia (C: -0.037 +/- 0.004, M: -0.026 +/- 0.008 mmHg.ml-1 x 100 g.min.mmHg PaCO2(-1)). CMRO2 in meningitis was not significantly different from control (C: 3.53 +/- 0.29, M: 3.51 +/- 0.22 ml O2.100 g-1.min-1). These findings indicate that cerebrovascular responsiveness to CO2 is preserved in experimental Hib meningitis. Furthermore, enhanced CBF together with unchanged CMRO2 indicates that "luxury" cerebral perfusion is present in this model of bacterial meningitis. |
| Databáze: | OpenAIRE |
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