Changes in Cerebral Blood Volume with Changes in Position in Awake and Anesthetized Subjects

Lovell, A.; Marshall, Alan C.; Elwell, Clare E.; Smith, Martin; Goldstone, J

doi:10.1097/00000539-200002000-00025

Cited by 34 publications

(32 citation statements)

References 20 publications

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“…The head-down position causes an increase in ICP, CBF and CBV 18,19 and a decrease in carotid artery blood flow. 20,21 All of these factors can reduce cerebral perfusion pressure, which can have a detrimental effect on cerebral tissue oxygenation.…”

Section: Discussionmentioning

confidence: 99%

The Effect of Gynaecological Laparoscopic Surgery on Cerebral Oxygenation

Lee

et al. 2006

J Int Med Res

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During gynaecological laparoscopic surgery, alterations in cerebral blood flow and intracranial pressure are frequently reported. These changes affect cerebral perfusion pressure and thus may affect cerebral oxygenation. In this prospective study, the effect of gynaecological laparoscopic surgery on cerebral oxygenation was examined by following the changes in regional cerebral oxygen saturation (rSO 2 ). Twenty-four female patients were enrolled. The mean rSO 2 was 65.5 ± 5.4% at baseline before surgery, 60.8 ± 5.6% when the patient was placed in the Trendelenburg position, 57.1 ± 9.3% after creation of pneumoperitoneum, and 64.0 ± 7.3% after the completion of surgery. During the period of pneumoperitoneum, rSO 2 fell below 50% in two hypercapnic patients. In comparison with baseline, rSO 2 declined significantly in the Trendelenburg position. The creation of pneumoperitoneum itself did not decrease the average rSO 2 value further unless the patients were hypercapnic.

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Section: Discussionmentioning

confidence: 99%

The Effect of Gynaecological Laparoscopic Surgery on Cerebral Oxygenation

Lee

et al. 2006

J Int Med Res

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“…In the present study, the ICP of SR cattle in a 30 cm head-up position was lower than that of RR cattle without the head-up position. Lovell et al report that the reduction in cerebral blood volume might be caused by a reduction in the volume of the venous and/or capillary compartments; they also suggest that changes in cerebral blood volume are unlikely to be the result of an increase in the arterial compartment, because arterial blood pressure did not change during tilting in their experiments [12]. In the present study, we observed similar results in the changing ICPs of cattle depending on head position, but arterial blood pressure showed no significant changes between the two tested groups.…”

Section: Discussionmentioning

confidence: 89%

“…In the present study, the ICPs of cattle in the sternal recumbent position were significantly lower than those of cattle in the lateral recumbent position during anesthesia. Changes in posture are known to affect the ICPs of humans and dogs [3,12,13,18]. Shah reports that the extradural pressure was greatest in the supine position and least in the prone position in human patients, the mean pressure being 22.6, 14.8 and 2.2 cmH 2 O in the supine, lateral and prone positions, respectively [18].…”

Section: Discussionmentioning

confidence: 99%

“…In the present study, the increase in ICP in the lateral recumbent position may be caused by an increase in cerebral blood volume with changes in posture. Changes in head position are known to affect ICP and cerebral blood volume in humans and cats [10,12]. In anesthetized human patients, differences have been observed between head-up and head-down tilt, specifically, cerebral blood volume was found to decrease with an 18° head-up tilt and increase with an 18° head-up tilt [12].…”

Section: Discussionmentioning

confidence: 99%

“…Changes in head position are known to affect ICP and cerebral blood volume in humans and cats [10,12]. In anesthetized human patients, differences have been observed between head-up and head-down tilt, specifically, cerebral blood volume was found to decrease with an 18° head-up tilt and increase with an 18° head-up tilt [12]. The ICP of cats was found to have increased significantly at 10 min in the head-down tilt position as compared with a control position [10].…”

Section: Discussionmentioning

confidence: 99%

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Development of a Neurosurgical Operating Table for Adult Cattle and Changes in Intracranial Pressure and Blood Pressure in Adult Cattle undergoing Long-Time Isoflurane Anesthesia

Arai

Yoshioka

Suzuki

et al. 2006

The Journal of Veterinary Medical Science

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ABSTRACT. We developed a neurosurgical operating table for restraining adult cattle in the sternal recumbent position during long-time inhalation anesthesia, and examined intracranial pressure (ICP), blood pressure and blood gases during isoflurane anesthesia. We confirmed that the maintenance of inhalation anesthesia, the restraint of cattle in the sternal recumbent position and bringing the cattle out of anesthesia could all be carried out safely using the operating table we produced. For the purposes of the present experiment, the cattle were divided into 2 groups: the SR group, which underwent sternal recumbency for 8 hr under isoflurane anesthesia using the neurosurgical operating table, and the RR group, which underwent right lateral recumbency for 3 hr under isoflurane anesthesia on a standard operating table. The mean ICP was found to be significantly lower in the SR group than in the RR group during anesthesia, and PaO 2 was significantly higher in the SR group. In the SR group, no complications such as regurgitation or ruminal tympany occurred for 8 hr after the induction of anesthesia, and recovery from anesthesia was uneventful. In contrast, all RR cattle showed ruminal tympany and regurgitated ruminal fluid at 3 hr after the induction of anesthesia. Thus, the neurosurgical operating table developed in the present study may be useful for long-time anesthesia and neurosurgery of adult cattle. Although small domestic animals such as goats and calves have been employed in neuroscientific research [7,14,25], such research is rarely carried out in large domestic animals such as adult cattle since safe methods for doing so have not yet been established. Central nervous system (CNS) disease such as hydrocephalus, intraorbital lymphoma and intraorbital abscess is reported in cattle [23]. These CNS diseases may require neurosurgical correction for functional recovery. In order to perform neurosurgery of cattle, inhalation anesthesia must be maintained for long periods of time [4]. In adult cattle, inhalation anesthesia is generally carried out in the lateral recumbent or dorsal recumbent position. When the posture of the animal is changed from the standing position to the lateral or dorsal recumbent position, heart rate, respiratory rate and plasma cortisol levels increase, while PaO 2 decreases [9,20,21]. In addition, general anesthesia and recumbency in cattle cause complications such as regurgitation and ruminal tympany. Therefore, in adult cattle, it is difficult to maintain inhalation anesthesia for long periods of time in the lateral recumbent or dorsal recumbent position. Furthermore, it is important to monitor and control intracranial pressure (ICP) during neurosurgery, but very little research has been conducted on changes in ICP in cattle [2].The purposes of this study were to develop a neurosurgical operating table for restraining adult cattle in the sternal recumbent position during long-time inhalation anesthesia, and to examine ICP, blood pressure and blood gases in isoflurane-anesthetized adult...

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Impact of Head‐Down Position on Cerebral Blood Flow in Healthy Subjects: An Arterial Spin‐Labeling MR Perfusion Study

Mejdoubi

Pavilla

Colombani

et al. 2019

Magnetic Resonance Imaging

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Background: A head-down (HD) position is used in some stroke centers to maintain cerebral perfusion (CP) in stroke patients. Purpose: To assess CP in healthy volunteers in the supine and HD (-15 ) positions. Study Type: Prospective. Population: Eighteen healthy subjects of 53 (AE8) years old. Field Strength/Sequence: 1.5T / arterial spin-labeling (ASL) in the supine position and after 4 minutes of HD position. Assessment: Regions of interest from reconstructed cerebral blood-flow (CBF) maps: subcortical nuclear gray matter (accumbens, amygdala, caudate, hippocampus, pallidum, putamen, thalamus), cortical gray matter (cGM), and white matter (WM). We also monitored hemodynamic parameters. Statistical Tests: Shapiro-Wilk test, analysis of variance (ANOVA) tests, Student's t-tests, and Pearson correlation analysis. Results: CBF was higher in women compared to men, whatever the position (mean difference of 17% in supine, and 13% in HD position). From supine to HD position, CBF was decreased in all regions (mean decrease of -7%). Simultaneously, mean arterial pressure and systolic blood pressure increased (respectively P = 0.004 and P < 0.001). Data Conclusion: The CBF decrease, despite increased hemodynamic parameters, may indicate efficient cerebral autoregulation. Our results seem to reflect only early cerebral autoregulation stages but may open the way towards a more precise understanding of CP. Level of Evidence: 1 Technical Efficacy: Stage 2

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Changes in Cerebral Blood Volume with Changes in Position in Awake and Anesthetized Subjects

Cited by 34 publications

References 20 publications

The Effect of Gynaecological Laparoscopic Surgery on Cerebral Oxygenation

The Effect of Gynaecological Laparoscopic Surgery on Cerebral Oxygenation

Development of a Neurosurgical Operating Table for Adult Cattle and Changes in Intracranial Pressure and Blood Pressure in Adult Cattle undergoing Long-Time Isoflurane Anesthesia

Impact of Head‐Down Position on Cerebral Blood Flow in Healthy Subjects: An Arterial Spin‐Labeling MR Perfusion Study

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