No effect of brain blood flow on ventilatory depression during sustained hypoxia

1989 ◽  
Vol 66 (4) ◽  
pp. 1674-1678 ◽  
Author(s):  
A. Suzuki ◽  
M. Nishimura ◽  
H. Yamamoto ◽  
K. Miyamoto ◽  
F. Kishi ◽  
...  
Keyword(s):  
Blood Flow ◽  
Brain Tissue ◽  
Initial Phase ◽  
Intermediate Phase ◽  
Minute Ventilation ◽  
Brain Blood Flow ◽  
Final Phase ◽  
Venous Pco2 ◽  
Tissue Pco2 ◽  
Sustained Hypoxia

Minute ventilation (VE) during sustained hypoxia is not constant but begins to decline within 10–25 min in adult humans. The decrease in brain tissue PCO2 may be related to this decline in VE, because hypoxia causes an increase in brain blood flow, thus resulting in enhanced clearance of CO2 from the brain tissue. To examine the validity of this hypothesis, we measured VE and arterial and internal jugular venous blood gases simultaneously and repeatedly in 15 healthy male volunteers during progressive and subsequent sustained isocapnic hypoxia (arterial PO2 = 45 Torr) for 20 min. It was assumed that jugular venous PCO2 was an index of brain tissue PCO2. Mean VE declined significantly from the initial (16.5 l/min) to the final phase (14.1 l/min) of sustained hypoxia (P less than 0.05). Compared with the control (50.9 Torr), jugular venous PCO2 significantly decreased to 47.4 Torr at the initial phase of hypoxia but did not differ among the phases of hypoxia (47.2 Torr for the intermediate phase and 47.7 Torr for the final phase). We classified the subjects into two groups by hypoxic ventilatory response during progressive hypoxia at the mean value. The decrease in VE during sustained hypoxia was significant in the low responders (n = 9) [13.2 (initial phase) to 9.3 l/min (final phase of hypoxia), P less than 0.01], but not in the high responders (n = 6) (20.9–21.3 l/min, NS). This finding could not be explained by the change of arterial or jugular venous gases, which did not significantly change during sustained hypoxia in either group.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of brain blood flow on hypoxic ventilatory response in humans

1987 ◽  
Vol 63 (3) ◽  
pp. 1100-1106 ◽  
Author(s):  
M. Nishimura ◽  
A. Suzuki ◽  
Y. Nishiura ◽  
H. Yamamoto ◽  
K. Miyamoto ◽  
...  
Keyword(s):  
Blood Flow ◽  
Ventilatory Response ◽  
Minute Ventilation ◽  
Venous Blood ◽  
Blood Gases ◽  
Interindividual Variation ◽  
Brain Blood Flow ◽  
Hypoxic Ventilatory Response ◽  
Arterial O2 Saturation ◽  
Sustained Hypoxia

To assess the effect of brain blood flow on hypoxic ventilatory response, we measured arterial and internal jugular venous blood gases and ventilation simultaneously and repeatedly in eight healthy male humans in two settings: 1) progressive and subsequent sustained hypoxia, and 2) stepwise and progressive hypercapnia. Ventilatory response to progressive isocapnic hypoxia [arterial O2 partial pressure 155.9 +/- 4.0 (SE) to 46.7 +/- 1.5 Torr] was expressed as change in minute ventilation per change in arterial O2 saturation and varied from -0.16 to -1.88 [0.67 +/- 0.19 (SE)] l/min per % among subjects. In the meanwhile, jugular venous PCO2 (PjCO2) decreased significantly from 51.0 +/- 1.1 to 47.3 +/- 1.0 Torr (P less than 0.01), probably due to the increase in brain blood flow, and stayed at the same level during 15 min of sustained hypoxia. Based on the assumption that PjCO2 reflects the brain tissue PCO2, we evaluated the depressant effect of fall in PjCO2 on hypoxic ventilatory response, using a slope for ventilation-PjCO2 line which was determined in the second set of experiments. Hypoxic ventilatory response corrected with this factor was -1.31 +/- 0.33 l/min per %, indicating that this factor modulated hypoxic ventilatory response in humans. The ventilatory response to progressive isocapnic hypoxia did not correlate with this factor but significantly correlated with the withdrawal test (modified transient O2 test), which was performed on a separate day. Accordingly we conclude that an increase in brain blood flow during exposure to moderate hypoxia may substantially attenuate the ventilatory response but that it is unlikely to be the major factor of the interindividual variation of progressive isocapnic hypoxic ventilatory response in humans.

scholarly journals A Case Study of Sandplay Therapy for a Boy with Tic

2021 ◽  
Vol 42 (5) ◽  
pp. 581-599
Author(s):  
Hee-og Sim
Keyword(s):  
Initial Phase ◽  
Intermediate Phase ◽  
Daily Life ◽  
Small Animals ◽  
Final Phase ◽  
Sandplay Therapy ◽  
Race Car ◽  
Football Match ◽  
Therapy Sessions

Objectives: This study examined sandplay therapy in an elementary school boy with tic problems. The goal of the therapy was to reduce his tic problems by offering a free and protected space of sandplay therapy.Methods: The sandboxes were analyzed focusing on analytical psychology and theories of sandplay therapy using Turner (2005)’s content themes, which were the most comprehensive themes.Results: Seventy-seven therapy sessions were performed. The client showed a race car that was stuck in the sand and then rescued by forklifts in the initial phase of therapy (1-2, a race car stuck in the sand). In the intermediate phase of the therapy (3-70, struggle), he showed regression, meeting the opposites, victory of small animals, construction, and death. In the final phase of therapy (71-77, race, death II, adaptation to reality), he showed race, death, and adaptation to reality.Conclusion: The client who was entering adolescence saw life as a race. However, the race car that was moving toward masculinity was stuck in the sand. Therefore, the car was sent for repairs. In the middle of the therapy, the boy showed various fights, accidents, and construction. Lastly, there were deaths of an alligator and a bear. By showing a football match, the long journey of developing ego ended. During the therapy, archetypal patterns, such as regression to the primitive psyche, the journey of masculinity as a boy, and confrontation between good and bad, appeared. Sandplay therapy, in a free and protected space, relieved the client’s tic problems with improvement of his daily life. Thus, this study demonstrates the effectiveness of sandplay therapy.

Effect of aortic balloon inflation on ventilation and brain stem blood flow in piglets

1989 ◽  
Vol 66 (5) ◽  
pp. 2174-2180 ◽  
Author(s):  
G. A. Green ◽  
R. A. Darnall ◽  
T. B. Bierd ◽  
J. M. Adams
Keyword(s):  
Blood Flow ◽  
Brain Stem ◽  
Minute Ventilation ◽  
Balloon Inflation ◽  
Acute Hypertension ◽  
Baroreceptor Stimulation ◽  
Tissue Pco2 ◽  
Aortic Obstruction ◽  
Spontaneously Breathing ◽  
Arterial Po2

Increases in brain stem blood flow (BBF) during hypoxia may decrease tissue PCO2/[H+], causing minute ventilation (VE) to decrease. To determine whether an increase in BBF, isolated from changes in arterial PO2 and PCO2, can affect respiration, we obstructed the thoracic aorta with a balloon in 31 intact and 24 peripherally chemobarodenervated, anesthetized, spontaneously breathing newborn piglets. Continuous measurements of cardiorespiratory variables were made before and during 2 min of aortic obstruction. Radiolabeled microspheres were used to measure BBF before and approximately 30 s after balloon inflation in eight intact and five denervated animals. After balloon inflation, there was a rapid increase in mean blood pressure in both the intact and denervated animals, followed within 10 s by a decrease in tidal volume and VE. In the intact animals, the decrease in VE after acute hypertension can be ascribed to a baroreceptor-mediated reflex. After peripheral chemobarodenervation, however, acute hypertension continued to produce a decrease in VE, which cannot be explained by baroreceptor stimulation. In these denervated animals, aortic balloon inflation was associated with an increase in BBF (13.1 +/- 2.7%; P less than 0.05). We speculate that the increase in BBF during hypoxia may contribute to the decrease in ventilation observed after carotid body denervation.

Brain adenosine concentration during hypoxia in rats

1981 ◽  
Vol 241 (2) ◽  
pp. H235-H242 ◽  
Author(s):  
H. R. Winn ◽  
R. Rubio ◽  
R. M. Berne
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Partial Pressure ◽  
Brain Tissue ◽  
Co2 Partial Pressure ◽  
Adenosine Concentration ◽  
Subsequent Measurement ◽  
Sustained Hypoxia ◽  
In Situ Technique

We analyzed brain tissue for adenosine and its metabolites, inosine and hypoxanthine, in rats during acute (30 s) hypoxia and during sustained (5 min) hypoxia and hypocarbia. Within 30 s of the onset of hypoxia, adenosine levels were increased from 0.34 +/- 0.08 (SE) to 1.65 +/- 0.33 nmol/g (P less than 0.005), paralleling temporally the changes in cerebral blood flow. During sustained hypoxia and hypocarbia, brain tissue was sampled by a fast (freeze-blow) or slow (in situ) freezing method. With the freeze-blow technique, adenosine concentrations remained stable between arterial partial pressure of O2 (PaO2) greater than 200 and 100 mmHg, doubled at PaO2 = 50 mmHg, and increased sevenfold (P less than 0.005) when PaO2 reached 30 mmHg. No increases in adenosine or its metabolites were noted with the in situ technique. During hypocarbia (arterial CO2 partial pressure less than 20 mmHg), adenosine concentrations increased with both sampling techniques. Freezing times in brain were measured during in situ freezing and were increased during hypoxia and decreased during hypocarbia. In conclusion, 1) adenosine concentrations in brain are increased during hypoxia, and 2) the in situ technique in rat does not appear to be optimal for sampling brain tissue for subsequent measurement of adenosine under conditions where cerebral blood flow is increased.

scholarly journals A Case Study of Sandplay Therapy for a Middle-aged Woman Who Goes the Way of Individuation Through Conflicts with an Adolescent Son

2020 ◽  
Vol 58 (2) ◽  
pp. 239-253
Author(s):  
Hee-og Sim
Keyword(s):  
Initial Phase ◽  
Intermediate Phase ◽  
Final Phase ◽  
Middle Aged ◽  
Sandplay Therapy ◽  
Aged Woman ◽  
Individuation Process ◽  
Middle Aged Woman ◽  
Therapy Sessions

This study explored a sandplay therapy case of a woman maturing through conflicts with an adolescent son. The goal of the therapy was to relieve her from conflicts with going through individuation process under a free and protected space in sandplay therapy. Forty-six therapy sessions were held. The client exhibited that she needed a conversation with her feminity and maternity in the initial phase of therapy (1-5, regression). In the intermediate phase of therapy (6-43, struggle), she displayed the scenes of meeting of opposites, shadow, death, nurturing and integration of opposites. In the final phase of therapy (44-46, transformation), she showed the acception of her life with leaving her situations to God. Through sandplay therapy in the free and protected space, this study showed the effectiveness of sandplay therapy since the client achieved individuation by showing the acceptance of her life and could control her enraged feelings.

Heterogeneity of Cerebral Blood Flow: a Fractal Approach

2000 ◽  
Vol 39 (02) ◽  
pp. 37-42 ◽  
Author(s):  
P. Hartikainen ◽  
J. T. Kuikka
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Fractal Dimension ◽  
Frontal Lobe ◽  
Fractal Analysis ◽  
Relative Dispersion ◽  
Emission Computed Tomography ◽  
Brain Blood Flow ◽  
Healthy Controls ◽  
Fractal Approach

Summary Aim: We demonstrate the heterogeneity of regional cerebral blood flow using a fractal approach and singlephoton emission computed tomography (SPECT). Method: Tc-99m-labelled ethylcysteine dimer was injected intravenously in 10 healthy controls and in 10 patients with dementia of frontal lobe type. The head was imaged with a gamma camera and transaxial, sagittal and coronal slices were reconstructed. Two hundred fifty-six symmetrical regions of interest (ROIs) were drawn onto each hemisphere of functioning brain matter. Fractal analysis was used to examine the spatial heterogeneity of blood flow as a function of the number of ROIs. Results: Relative dispersion (= coefficient of variation of the regional flows) was fractal-like in healthy subjects and could be characterized by a fractal dimension of 1.17 ± 0.05 (mean ± SD) for the left hemisphere and 1.15 ± 0.04 for the right hemisphere, respectively. The fractal dimension of 1.0 reflects completely homogeneous blood flow and 1.5 indicates a random blood flow distribution. Patients with dementia of frontal lobe type had a significantly lower fractal dimension of 1.04 ± 0.03 than in healthy controls. Conclusion: Within the limits of spatial resolution of SPECT, the heterogeneity of brain blood flow is well characterized by a fractal dimension. Fractal analysis may help brain scientists to assess age-, sex- and laterality-related anatomic and physiological changes of brain blood flow and possibly to improve precision of diagnostic information available for patient care.

Mechanisms of improvement in pulmonary gas exchange during isovolemic hemodilution

1999 ◽  
Vol 87 (1) ◽  
pp. 132-141 ◽  
Author(s):  
Steven Deem ◽  
Richard G. Hedges ◽  
Steven McKinney ◽  
Nayak L. Polissar ◽  
Michael K. Alberts ◽  
...  
Keyword(s):  
Blood Flow ◽  
Fractal Dimension ◽  
Gas Exchange ◽  
Spatial Correlation ◽  
Pulmonary Blood Flow ◽  
Minute Ventilation ◽  
Flow Distribution ◽  
Pulmonary Gas Exchange ◽  
Normal Lung ◽  
Blood Flow Distribution

Severe anemia is associated with remarkable stability of pulmonary gas exchange (S. Deem, M. K. Alberts, M. J. Bishop, A. Bidani, and E. R. Swenson. J. Appl. Physiol. 83: 240–246, 1997), although the factors that contribute to this stability have not been studied in detail. In the present study, 10 Flemish Giant rabbits were anesthetized, paralyzed, and mechanically ventilated at a fixed minute ventilation. Serial hemodilution was performed in five rabbits by simultaneous withdrawal of blood and infusion of an equal volume of 6% hetastarch; five rabbits were followed over a comparable time. Ventilation-perfusion (V˙a/Q˙) relationships were studied by using the multiple inert-gas-elimination technique, and pulmonary blood flow distribution was assessed by using fluorescent microspheres. Expired nitric oxide (NO) was measured by chemiluminescence. Hemodilution resulted in a linear fall in hematocrit over time, from 30 ± 1.6 to 11 ± 1%. Anemia was associated with an increase in arterial [Formula: see text] in comparison with controls ( P < 0.01 between groups). The improvement in O2 exchange was associated with reducedV˙a/Q˙heterogeneity, a reduction in the fractal dimension of pulmonary blood flow ( P = 0.04), and a relative increase in the spatial correlation of pulmonary blood flow ( P = 0.04). Expired NO increased with anemia, whereas it remained stable in control animals ( P < 0.0001 between groups). Anemia results in improved gas exchange in the normal lung as a result of an improvement in overallV˙a/Q˙matching. In turn, this may be a result of favorable changes in pulmonary blood flow distribution, as assessed by the fractal dimension and spatial correlation of blood flow and as a result of increased NO availability.

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