Effects of hypercapnia, hypocapnia, and hyperoxemia on brain morphometrics determined by use of T1-weighted magnetic resonance imaging in isoflurane-anesthetized dogs.
Summary of "Effects of hypercapnia, hypocapnia, and hyperoxemia on brain morphometrics determined by use of T1-weighted magnetic resonance imaging in isoflurane-anesthetized dogs."
Objective-To evaluate the effects of various combinations of Paco(2) and Pao(2) values on brain morphometrics. Animals-6 healthy adult dogs. Procedures-A modified Latin square design for randomization was used. Dogs were anesthetized with propofol (6 to 8 mg/kg, IV), and anesthesia was maintained with isoflurane (1.7%) and atracurium (0.2 mg/kg, IV, q 30 min). Three targeted values of Paco(2) (20, 40, and 80 mm Hg) and 2 values of Pao(2) (100 and 500 mm Hg) were achieved in each dog, yielding 6 combinations during a single magnetic resonance (MR) imaging session. When the endpoints were reached, dogs were given at least 5 minutes for physiologic variables to stabilize before T1-weighted MR images were obtained. Total brain volume (TBV) and lateral ventricular volume (LVV) were calculated from manually drawn contours of areas of interest by use of a software program, with each dog serving as its own control animal. Three blinded investigators subjectively evaluated the lateral ventricular size (LVS) and the cerebral sulci width (CSW). Brain morphometric values were compared among the target blood gas states. Results-No significant differences in TBV were found among target states. The LVV was significantly greater during hypocapnia, compared with hypercapnia at the same Pao(2) value. With regard to the subjective evaluations, there were no significant differences among evaluators or among combinations of Pao(2) and Paco(2) values. Conclusions and Clinical Relevance-The changes observed in LVV during hypocapnia and hypercapnia may serve as a potential confounding factor when neuromorphometric evaluations are performed in anesthetized dogs. (Am J Vet Res 2010;71:1011-1018).
Department of Clinical Studies, Ontario Veterinary College, University of Guelph, Guelph, ON N1G 2W1, Canada.
This article was published in the following journal.
Name: American journal of veterinary research
- PubMed Source: http://www.ncbi.nlm.nih.gov/pubmed/20807139
- DOI: http://dx.doi.org/10.2460/ajvr.71.9.1011
Medical and Biotech [MESH] Definitions
Threshold Limit Values
Standards for limiting worker exposure to airborne contaminants. They are the maximum concentration in air at which it is believed that a particular substance will not produce adverse health effects with repeated daily exposure. It can be a time-weighted average (TLV-TWA), a short-term value (TLV-STEL), or an instantaneous value (TLV-Ceiling). They are expressed either as parts per million (ppm) or milligram per cubic meter (mg/m3).
A phenotypic outcome (physical characteristic or disease predisposition) that is determined by more than one gene. Polygenic refers to those determined by many genes, while oligogenic refers to those determined by a few genes.
Clinical manifestation consisting of a deficiency of carbon dioxide in arterial blood.
A clinical manifestation of abnormal increase in the amount of carbon dioxide in arterial blood.
Tissue NECROSIS in any area of the brain, including the CEREBRAL HEMISPHERES, the CEREBELLUM, and the BRAIN STEM. Brain infarction is the result of a cascade of events initiated by inadequate blood flow through the brain that is followed by HYPOXIA and HYPOGLYCEMIA in brain tissue. Damage may be temporary, permanent, selective or pan-necrosis.
The roles of the alveolar and systemic CO₂ on the lung mechanics were investigated in dogs subjected to cardiopulmonary bypass. Low-frequency pulmonary impedance data (Z(L)) were collected in open-c...
Cerebral vessels may regulate cerebral blood flow by responding to changes in carbon dioxide (CO(2)) through nitric oxide (NO) production. To better determine the role of NO production by human adult...
Cerebrovascular reactivity to vasodilatory hypercapnic and vasoconstrictive hypocapnic challenges is known to be altered in several hemodynamic disorders, which is often attributable to changes in smo...
We investigated the effects of hypocapnia in normal subjects on airway tone while controlling airway cooling and drying. We hypothesized that airway tone is positively related to the degree of hypocap...
BACKGROUND: Cerebral blood flow (CBF) measurements are helpful in managing patients with traumatic brain injury (TBI), and testing the cerebrovascular reactivity to CO(2) provides information about in...
Prospective, controlled, randomized crossover volunteer study to investigate the effect of hyperoxemia due to inhalation of oxygen (80% inspiratory fraction) via reservoir-face-mask on blo...
This study will evaluate magnetic resonance imaging (MRI ) methods for measuring changes in the brain's blood flow during hypercapnia (a condition of excess carbon dioxide in the blood)....
The proposed study will measure the decrease in time to meet discharge criteria from the PACU and a reduction in the incidence of adverse events when hypercapnic hyperpnoea is used during...
The objective of this pilot study is to develop and evaluate a whole body MRI technique for detecting cancer metastases. The whole body MRI will include T1-weighted and T2-weighted phase-...
For some upper ureteral and renal stones,ureteroscopic lithotripsy needs to be performed under general anesthesia with interrupted suspension of mechanical ventilation, which could result...