Effect on the Cushing response of different rates of expansion of a supratentorial mass

1978 ◽  
Vol 49 (1) ◽  
pp. 61-70 ◽  
Author(s):  
Abdul Hamid Zidan ◽  
John P. Girvin
Keyword(s):  
Heart Rate ◽  
Full Range ◽  
Blood Gases ◽  
Systemic Arterial Pressure ◽  
Critical Volume ◽  
Experimental Conditions ◽  
Content Type ◽  
Cerebral Dysfunction ◽  
Cushing Response ◽  
Supratentorial Mass

✓ The effects on the three components (respiration, blood pressure, and heart rate) of the Cushing response (CR) were studied in cats by the continuous expansion of a supratentorial balloon. The rate of expansion was varied over the range of 0.006 to 0.6 ml/min, during which systemic arterial pressure, heart rate, respiratory rate, and blood gases were monitored. For the different rates the time the CR took to develop, and the balloon volume required for that development were measured. The final volume (“critical volume”) for eliciting the CR was more or less constant over the full range of rates of infusion (balloon expansion), a fact that supports the Monro-Kellie doctrine. This constancy of critical volume (CCV) gives rise to a highly statistically significant relationship between the rate of infusion and the latency to the production of the CR, and it is described by a power curve. Thus the development of cerebral dysfunction under these experimental conditions is independent of the rate of expansion and only dependent upon this critical volume. Exceptions to this concept of a critical volume, at the extreme of rates of expansion of lesions in patients, are predicted.

Acute intracranial hypertension and brain-stem blood flow

1984 ◽  
Vol 60 (3) ◽  
pp. 566-571 ◽  
Author(s):  
Seigo Nagao ◽  
Norio Sunami ◽  
Takumi Tsutsui ◽  
Yutaka Honma ◽  
Fumiyuki Momma ◽  
...  
Keyword(s):  
Blood Flow ◽  
Intracranial Hypertension ◽  
Brain Stem ◽  
Inferior Colliculus ◽  
Medulla Oblongata ◽  
Systemic Arterial Pressure ◽  
Content Type ◽  
Cushing Response ◽  
The Mean ◽  
Mass Lesions

✓ This study has been carried out to evaluate the effect of supratentorial mass lesions on the local cerebral blood flow (CBF) of the brain stem. Local CBF of the thalamus, inferior colliculus, and medulla oblongata, and supra- and infratentorial pressure were serially measured in 52 cats with intracranial hypertension produced by supratentorial balloon expansion. The mean control local CBF's in the thalamus, inferior colliculus, and medulla oblongata were 37.5, 42.1, and 30.7 ml/100 gm/min, respectively. At 20 to 30 mm Hg of supratentorial pressure, the local CBF of the thalamus started to decrease, and at 20 mm Hg of infratentorial pressure, the local CBF of the inferior colliculus began to decrease. Finally, at 40 to 60 mm Hg of infratentorial pressure, the local CBF of the medulla oblongata was affected. At the beginning of uncal herniation, indicated by anisocoria, the mean local CBF of the inferior colliculus abruptly decreased from 33.7 to 19.6 ml/100 gm/min in 16 cats. The Cushing response was evoked at a mean supratentorial pressure of 93.4 mm Hg and infratentorial pressure of 49.9 mm Hg in 16 cats. When the systemic arterial pressure was increased to the highest level in 13 cats, the mean local CBF of the medulla oblongata did not show significant change (a decrease from 22.8 to 20.9 ml/100 gm/min). The results suggest that at the beginning of uncal herniation, the local CBF of the upper brain stem markedly decreased. During the Cushing response, the local CBF of the medulla oblongata did not change significantly.

Experimental neurogenic pulmonary edema

1981 ◽  
Vol 54 (5) ◽  
pp. 627-631 ◽  
Author(s):  
Julian T. Hoff ◽  
Merry Nishimura ◽  
Jose Garcia-Uria ◽  
Sandra Miranda
Keyword(s):  
Pulmonary Edema ◽  
Intracranial Hypertension ◽  
Perfusion Pressure ◽  
Systemic Arterial Pressure ◽  
Neurogenic Pulmonary Edema ◽  
Content Type ◽  
Systemic Arterial Hypertension ◽  
Cushing Response ◽  
Intraventricular Infusion ◽  
Sympathetic Discharge

✓ Neurogenic pulmonary edema (NPE) was produced consistently in normal cats by increasing intracranial pressure with an intraventricular infusion of mock cerebrospinal fluid. The usual elevation of systemic arterial pressure (SAP) that follows severe intracranial hypertension (the “Cushing response”) was controlled by blood withdrawal at variable rates to achieve and maintain constant cerebral perfusion pressure (CPP) in three groups of cats of 50, 20, and 0 mm Hg, respectively, for 30 minutes. In this model, NPE occurs in the absence of increased SAP and in the presence of decreasing CPP. These results indicate that systemic arterial hypertension is not an essential stimulus for the development of NPE, and suggest that the lungs are directly affected by the intense sympathetic discharge evoked by severe intracranial hypertension.

Heart Rate Variability, Homeostasis, and Brain Function

2012 ◽  
Vol 26 (4) ◽  
pp. 178-203 ◽  
Author(s):  
Francesco Riganello ◽  
Sergio Garbarino ◽  
Walter G. Sannita
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
Vegetative State ◽  
Communication Disorders ◽  
Affective States ◽  
Experimental Conditions ◽  
Cardiovascular Research ◽  
Sensory Stimuli ◽  
Additional Information ◽  
Brain Injured

Measures of heart rate variability (HRV) are major indices of the sympathovagal balance in cardiovascular research. These measures are thought to reflect complex patterns of brain activation as well and HRV is now emerging as a descriptor thought to provide information on the nervous system organization of homeostatic responses in accordance with the situational requirements. Current models of integration equate HRV to the affective states as parallel outputs of the central autonomic network, with HRV reflecting its organization of affective, physiological, “cognitive,” and behavioral elements into a homeostatic response. Clinical application is in the study of patients with psychiatric disorders, traumatic brain injury, impaired emotion-specific processing, personality, and communication disorders. HRV responses to highly emotional sensory inputs have been identified in subjects in vegetative state and in healthy or brain injured subjects processing complex sensory stimuli. In this respect, HRV measurements can provide additional information on the brain functional setup in the severely brain damaged and would provide researchers with a suitable approach in the absence of conscious behavior or whenever complex experimental conditions and data collection are impracticable, as it is the case, for example, in intensive care units.

Identifying Patterns in Complex Field Data

2017 ◽  
Vol 225 (3) ◽  
pp. 268-284 ◽  
Author(s):  
Andrew J. White ◽  
Dieter Kleinböhl ◽  
Thomas Lang ◽  
Alfons O. Hamm ◽  
Alexander L. Gerlach ◽  
...  
Keyword(s):  
Heart Rate ◽  
Panic Disorder ◽  
Latent Class ◽  
Treatment Protocol ◽  
Situational Factors ◽  
Self Report ◽  
Complex Field ◽  
Cluster Assignment ◽  
Experimental Conditions ◽  
Conventional Analysis

Abstract. Ambulatory assessment methods are well suited to examine how patients with panic disorder and agoraphobia (PD/A) undertake situational exposure. But under complex field conditions of a complex treatment protocol, the variability of data can be so high that conventional analytic approaches based on group averages inadequately describe individual variability. To understand how fear responses change throughout exposure, we aimed to demonstrate the incremental value of sorting HR responses (an index of fear) prior to applying averaging procedures. As part of their panic treatment, 85 patients with PD/A completed a total of 233 bus exposure exercises. Heart rate (HR), global positioning system (GPS) location, and self-report data were collected. Patients were randomized to one of two active treatment conditions (standard exposure or fear-augmented exposure) and completed multiple exposures in four consecutive exposure sessions. We used latent class cluster analysis (CA) to cluster heart rate (HR) responses collected at the start of bus exposure exercises (5 min long, centered on bus boarding). Intra-individual patterns of assignment across exposure repetitions were examined to explore the relative influence of individual and situational factors on HR responses. The association between response types and panic disorder symptoms was determined by examining how clusters were related to self-reported anxiety, concordance between HR and self-report measures, and bodily symptom tolerance. These analyses were contrasted with a conventional analysis based on averages across experimental conditions. HR responses were sorted according to form and level criteria and yielded nine clusters, seven of which were interpretable. Cluster assignment was not stable across sessions or treatment condition. Clusters characterized by a low absolute HR level that slowly decayed corresponded with low self-reported anxiety and greater self-rated tolerance of bodily symptoms. Inconsistent individual factors influenced HR responses less than situational factors. Applying clustering can help to extend the conventional analysis of highly variable data collected in the field. We discuss the merits of this approach and reasons for the non-stereotypical pattern of cluster assignment across exposures.

Craniocerebral missile injuries in the monkey: an experimental physiological model

1972 ◽  
Vol 36 (1) ◽  
pp. 43-49 ◽  
Author(s):  
Arthur M. Gerber ◽  
Robert A. Moody
Keyword(s):  
Rhesus Monkeys ◽  
Common Factor ◽  
Blood Gases ◽  
Physiological Model ◽  
Content Type ◽  
Epidural Compression ◽  
The Brain ◽  
Strong Suspicion ◽  
Fine Print ◽  
Carotid Flow

✓ Experiments were carried out on rhesus monkeys to determine what physiological parameters were most closely correlated with death due to craniocerebral missile injuries. Observations of intracranial pressure, blood pressure, carotid flow, blood gases, respiratory rate, depth and volume, and electroencephalograms were made. These parameters were compared in survivors and nonsurvivors as were the pathological injuries. The most important single parameter that correlated with death was the drop in carotid flow. As this same correlation has been observed in epidural compression experiments in the monkey, there is a strong suspicion that reduced blood flow to the brain as measured by carotid flow is a common factor in craniocerebral missile injuries and epidural compression injuries.

Effect of stimulation of the medullary reticular formation on cerebral vasomotor tonus and intracranial pressure

1987 ◽  
Vol 66 (4) ◽  
pp. 548-554 ◽  
Author(s):  
Seigo Nagao ◽  
Tsukasa Nishiura ◽  
Hideyuki Kuyama ◽  
Masakazu Suga ◽  
Takenobu Murota
Keyword(s):  
Intracranial Pressure ◽  
Reticular Formation ◽  
Cerebral Blood Volume ◽  
Systemic Arterial Pressure ◽  
Brain Swelling ◽  
Dorsomedial Nucleus ◽  
Medullary Reticular Formation ◽  
Content Type ◽  
Fine Print ◽  
Stimulation Of

✓ The authors report the results of a study to evaluate the effect of stimulation of the medullary reticular formation on cerebral vasomotor tonus and intracranial pressure (ICP) after the hypothalamic dorsomedial nucleus and midbrain reticular formation were destroyed. Systemic arterial pressure (BP), ICP, and local cerebral blood volume (CBV) were continuously recorded in 32 cats. To assess the changes in the cerebral vasomotor tonus, the vasomotor index defined by the increase in ICP per unit change in BP was calculated. In 29 of the 32 animals, BP, ICP, and CBV increased simultaneously immediately after stimulation. The increase in ICP was not secondary to the increase in BP, because the vasomotor index during stimulation was significantly higher than the vasomotor index after administration of angiotensin II. The vasomotor index was high during stimulation of the area around the nucleus reticularis parvocellularis. In animals with the spinal cord transected at the C-2 vertebral level, ICP increased without a change in BP. These findings indicate that the areas stimulated in the medullary reticular formation play an important role in decreasing cerebral vasomotor tonus. This effect was not influenced by bilateral superior cervical ganglionectomy, indicating that there is an intrinsic neural pathway that regulates cerebral vasomotor tonus directly. In three animals, marked biphasic or progressive increases in ICP up to 100 mm Hg were evoked by stimulation. The reduction of cerebral vasomotor tonus and concomitant vasopressor response induced by stimulation of the medullary reticular formation may be one of the causes of acute brain swelling.

The effects of mass-induced intracranial pressures on arterial hypertension and survival in awake cats

1972 ◽  
Vol 37 (5) ◽  
pp. 514-527 ◽  
Author(s):  
Stanley J. Goodman ◽  
Donald P. Becker ◽  
John Seelig
Keyword(s):  
Intracranial Pressure ◽  
Systemic Hypertension ◽  
Content Type ◽  
Arterial Blood ◽  
Mass Size ◽  
Intracranial Pressures ◽  
Relationship Of ◽  
The Relationship ◽  
Awake Cats ◽  
Supratentorial Mass

✓ Intracranial pressures above and below the tentorium, arterial blood pressure, heart rate, and respiratory rate were recorded continuously before, during, and after expansion of a supratentorial mass in awake unsedated cats. In general, as the mass enlarged, the intracranial pressure rose; however, considerable variation was observed among animals with respect to specific mass size and associated intracranial pressures. There was considerable variation in the relationship of supratentorial pressure to infratentorial pressure. No animal survived that had sustained a mass-induced pressure exceeding 1100 mm H2O, and survival was shorter with greater pressures. Systemic hypertension occurred always and only when the infratentorial pressure exceeded 600 mm H2O, regardless of the magnitude of the associated supratentorial intracranial pressure. The methodological limitations of previous studies of mass-induced intracranial hypertension appear to have been substantially reduced by the technique described.

Nocturnal headache: systemic arterial pressure and heart rate during sleep

Cephalalgia ◽  
1983 ◽  
Vol 3 (1_suppl) ◽  
pp. 54-57 ◽  
Author(s):  
Fabio Cirignotta ◽  
Giorgio Coccagna ◽  
Tommaso Sacquegna ◽  
Emiliana Sforza ◽  
Giuseppe Lamontanara ◽  
...  
Keyword(s):  
Heart Rate ◽  
Arterial Pressure ◽  
Rem Sleep ◽  
Continuous Monitoring ◽  
Systemic Arterial Pressure ◽  
Fréquence Cardiaque ◽  
The Awakening ◽  
Sono Stati ◽  
Autonomic Instability ◽  
Polygraphic Recording

In order to evaluate autonomic nervous system changes occurring before nocturnal headache attacks, we studied three subjects (one male, two females) suffering from chronic migraine. All three patients underwent a nocturnal polygraphic recording including continuous monitoring of systemic arterial pressure and heart rate. Two subjects showed increases and irregularities of arterial pressure before awakening with headache. These changes began during N–REM sleep and lasted during REM sleep preceding the awakening with headache. Heart rate did not change before the attacks. These findings do not support the hypothesis that autonomic instability during REM sleep represents the precipitating factor of the attacks. On a étudié avec des méthodes polygrafiques trois sujets (1 homme et deux femmes) souffrant d'hémicranie chronique avec des crises nocturnes. Chez deux malades les crises étaient précédées d'augmentation et d'irrégularité de la tension artérielle. Ces modifications commençaient pendant le sommeil N-REM et contineaient pendant le sommeil REM qui précédait le réveil avec hémicranie. La fréquence cardiaque n'a pas subi de modification avant les crises. Les résultats obtenus ne confirment l'hypothèse selon laquelle le facteur causant les crises est l'instabilité anticronique à la fase REM. Sono stati studiati con metodiche poligrafiche 3 soggetti (1 maschio e 2 femmine) affetti da emicrania cronica con attacchi notturni. In 2 di essi gli attacchi erano preceduti da incrementi ed irregolarità della pressione arteriosa. Tali modificazioni iniziavano durante il sonno N-REM e perduravano nel corso del sonno REM che precedeva il risveglio con cefalea. La frequenza cardiaca non si modificava prima dell'attacco. I risultati ottenuti non confermano l'ipotesi che il fattore precipitante gli attacchi emicranici sia l'instabilità anticronica della fase REM.

scholarly journals Adaptations in traditional courtyard houses in Baghdad, Iraq

2017 ◽  
Vol 35 (4) ◽  
pp. 348-363 ◽  
Author(s):  
Rand H.M. Agha ◽  
John M. Kamara
Keyword(s):  
Design Methodology ◽  
Full Range ◽  
Physical Structure ◽  
Structured Interviews ◽  
Content Type ◽  
Case Study Analysis ◽  
Physical Spaces ◽  
Adaptation Model

Purpose The purpose of this paper is to investigate the adaptations that have been made to traditional courtyard houses (TCHs) in Baghdad, Iraq. The aim is to develop an understanding of various factors in the adaptation of these buildings to suit contemporary lifestyles, which will contribute to the wider field of building adaptability. Design/methodology/approach Empirical evidence was collected through case studies of 12 TCHs in the Al-Kadhimiya area of Baghdad, which involved a physical survey of buildings and semi-structured interviews with 24 occupants. Findings Case study analysis show that building adaptability involves both a change to physical spaces and also to lifestyles; with the latter being more likely when there are limitations in how much change can be made to the physical structure. Research limitations/implications The focus of this research is mainly on users’ adaptation of spaces and therefore does not consider the full range of stakeholders involved in the adaptation process. The findings also only apply to the cases considered and may not be applicable to other house types or locations. Originality/value Studies on building adaptability mostly focus on the ease of change to the building fabric, although the role of users is acknowledged. This study provides insights into the complexity and variety of changes that users can make, which are influenced by lifestyles and driven by the need for comfort. These insights are represented in an adaptation model, which can serve as a basis for further research.

Influence of occupational heat stress on labour productivity – a case study from Chennai, India

2016 ◽  
Vol 65 (2) ◽  
pp. 245-255 ◽  
Author(s):  
Jeremiah Chinnadurai ◽  
Vidhya Venugopal ◽  
Kumaravel P ◽  
Paramesh R
Keyword(s):  
Climate Change ◽  
Heart Rate ◽  
Heat Stress ◽  
Pearson Correlation ◽  
Labour Productivity ◽  
Productivity Loss ◽  
Threshold Limit Value ◽  
Control Measures ◽  
Economic Losses ◽  
Content Type

Purpose – Raise in temperatures due to climate change is likely to increase the heat stress in occupations that are physically exerting and performed outdoors which might potentially have adverse health and productivity consequences. The purpose of this paper is to estimate the productivities in construction work under the influence of heat stress using the predicted mean vote (PMV) index. Design/methodology/approach – Field studies were conducted during May 2014 which is summer time in Chennai. Continuous heart rate of workers and wet bulb globe temperature measurements are conducted for workers engaged in different jobs in construction. Metabolic rates and the workload of the workers from heart rate were calculated using the ISO method 8996 and the PMV values are calculated using the tool developed by Malchaire based on the method ISO 7730. Direct observations and personal interviews were conducted to substantiate the productivity estimations. Findings – The results showed that workers working outdoors with moderate and heavy workload exceeded the threshold limit value of 28°C and had adverse productivity impacts (18-35 per cent productivity loss), whereas the workers engaged in light indoor work was not affected by heat stress and consequent productivity losses. The productivity estimations using the PMV index is found to be statistically significant for three types of construction works (Pearson correlation coefficient value of −0.78) and also correlated well with the observations and self-reported productivities of the workers. Originality/value – The method used in this paper provides a scientific and reliable estimation of the productivities which may benefit the industry to set realistic project completion goals in hot weather and also implement interventions and policies to protect workers’ health. Developing adaptive strategies and implementing control measures are the need of the hour to protect worker’s health and economic losses in the face of climate change.

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