scholarly journals Perfusion heterogeneity in the pulmonary acinus

1998 ◽  
Vol 84 (3) ◽  
pp. 933-938 ◽  
Author(s):  
Nobuhiro Tanabe ◽  
Thomas M. Todoran ◽  
Gerald M. Zenk ◽  
Brenda R. Bunton ◽  
Wiltz W. Wagner ◽  
...  
Keyword(s):  
Blood Flow ◽  
Fluorescence Microscopy ◽  
Capillary Blood ◽  
Fluorescent Dye ◽  
Time Difference ◽  
Appearance Time ◽  
Pulmonary Acinus ◽  
The Mean ◽  
The Difference ◽  
Dilution Curves

There is little information on the distribution of acinar perfusion because it is difficult to resolve blood flow within such small regions. We hypothesized that the known heterogeneity of arteriolar blood flow and capillary blood flow would result in heterogeneous acinar perfusion. To test this hypothesis, the passage of fluorescent dye boluses through the subpleural microcirculation of isolated dog lobes was videotaped by using fluorescence microscopy. As the videotapes were replayed, dye-dilution curves were recorded from each of the tributary branches of Y-shaped venules that drained an acinus. From the dye curves, we calculated the mean appearance time of each curve. The difference in mean appearance times between venular tributary branches was small in most cases. In 43% of the observed venular branch pairs, the dye curves were essentially superimposable (the mean appearance-time difference was <5%); and in another 42%, the mean appearance-time difference between curves was 5–10%. From these results, we conclude that acinar perfusion is unexpectedly homogeneous.

Role of positive airway pressure on pulmonary acinar perfusion heterogeneity

2000 ◽  
Vol 89 (5) ◽  
pp. 1943-1948 ◽  
Author(s):  
Nobuhiro Tanabe ◽  
Thomas M. Todoran ◽  
Gerald M. Zenk ◽  
Jun Aono ◽  
Wiltz W. Wagner ◽  
...  
Keyword(s):  
Airway Pressure ◽  
Positive Airway Pressure ◽  
Appearance Time ◽  
Capillary Networks ◽  
Pulmonary Acinus ◽  
Capillary Resistance ◽  
The Mean ◽  
Lung Lobes ◽  
Dilution Curves

Perfusion of the pulmonary acinus has been shown to be generally homogeneous, but there is a significant component that is heterogeneous. To investigate the contribution of the alveolar septal capillary network to acinar perfusion heterogeneity, the passage of fluorescent dye boluses through the subpleural microcirculation of isolated dog lung lobes was videotaped using fluorescence microscopy. As the videotapes were replayed, dye-dilution curves were recorded from each of the tributary branches of Y-shaped venules that drained single acini. For each Y-shaped venule, the mean appearance time difference between the pair of tributary branches was calculated from the dye curves. When the complex septal capillary networks were derecruited by high positive airway pressure, venular perfusion became proportionally more homogeneous. This result shows that septal capillary resistance and pathlength differences are important contributors to intra-acinar perfusion heterogeneity.

Similarity of blood flows using indocyanine prepared in saline or distilled water

1975 ◽  
Vol 39 (4) ◽  
pp. 689-691
Author(s):  
L. L. Aarhus ◽  
D. E. Donald
Keyword(s):  
Blood Flow ◽  
Indocyanine Green ◽  
Indicator Dilution ◽  
Distilled Water ◽  
Appearance Time ◽  
Blood Flows ◽  
Mean Error ◽  
Indocyanine Green Dye ◽  
The Mean ◽  
Dilution Curves

Directly measured blood flow pumped through a mixer circuit was compared to estimates of flow from indicator dilution curves derived from bolus injections of indocyanine green dye prepared in 0.9% saline (saline dye) and in triple-distilled water (3 D dye). At flows whose mean appearance time was 1.6 s, the mean error of estimate +/-SD of 2.3 +/- 5.1% using 3 D dye was significantly different (P less than 0.05) from that of 5.6 +/- 7.0% using saline dye. Essentially, there was no difference in estimates of blood flow with each dye solution when mean appearance time was increased to 3.8 s. Thus, the error, which was perhaps due to electrolyte in the concentrated indocyanine green dye (saline dye) and subsequent slowed rate of optical stabilization after dilution in plasma, is small and does not explain the overestimation by indocyanine dilution curves of blood flow in intact dogs.

Arterial hematocrit and separation of cells and plasma in the dog kidney

1964 ◽  
Vol 207 (1) ◽  
pp. 128-132 ◽  
Author(s):  
Francis P. Chinard ◽  
Theodore Enns ◽  
Mary F. Nolan
Keyword(s):  
Blood Flow ◽  
Volume Of Distribution ◽  
Human Albumin ◽  
Indicator Dilution ◽  
Regression Equations ◽  
Dilution Technique ◽  
Transit Times ◽  
Dog Kidney ◽  
The Mean ◽  
The Difference

With the indicator-dilution technique, the mean transit times of cells (tr) labeled with Cr51 and of plasma (tpl) labeled with T-1824 or as human albumin-I131 decrease as the arterial hematocrit (Hct) decreases. The regression equations are: tr = 0.0388 Hct + 1.73 and tpl = 0.0596 Hct + 1.69. The separation of cells and plasma labels, as measured by the difference of the mean transit times (Δt), is also related to the hematocrit. Δt = 0.00895 Hct + 0.269. There is an excess plasma label volume of distribution per 100 g kidney, ΔVpl, which may be intra- or extravascular. ΔVpl = QrΔt (1 - Hct), where Qr is blood flow per 100 g kidney. ΔVpl is independent of tr and of Hct. However, ΔVpl increases with Qr. ΔVpl = 0.127 Qr + 1.79. The hypothesis that the separation of cells and plasma results from transcapillary passage of the plasma labels is consistent with but is not established by the data.

In Vivo Fluorescence Microscopy of Microcirculation in the Renal Cortex of Mice

1993 ◽  
Vol 34 (2) ◽  
pp. 168-173 ◽  
Author(s):  
B. Högström ◽  
P. Rooth ◽  
O. Sunnegårdh ◽  
S.-O. Hietala
Keyword(s):  
Blood Flow ◽  
Fluorescence Microscopy ◽  
Experimental Model ◽  
Rating Scale ◽  
Capillary Blood ◽  
Capillary Blood Flow ◽  
Cortical Blood Flow ◽  
In Vivo Fluorescence ◽  
Renal Cortical Blood Flow

An experimental model using in vivo fluorescence microscopy for studies of renal cortical blood flow was tested in 40 mice. The model was suitable for testing a wide variety of hypotheses concerning alterations in renal cortical blood flow, including the possibility of inhomogeneous capillary blood flow distribution in response to i.v. infusions. The experimental model was tested for the effects of i.v. infusion of mannitol (0.3 mol/l). Effects of anesthesia and mechanical kidney fixation on renal cortical blood flow were studied. Neuroleptic analgesia was less hazardous to the animals than pentobarbital. Due to artifacts from respiratory and peristaltic motion, it was not possible to use neuroleptic analgesia without mechanical kidney fixation. A rating scale was designed for evaluating the capillary blood flow. The correlation between repeated ratings by the same observer was 0.806 and between 2 different observers 0.59.

In Vivo Fluorescence Microscopy of Microcirculation in the Renal Cortex of Mice

1993 ◽  
Vol 34 (5) ◽  
pp. 500-504 ◽  
Author(s):  
B. Högström ◽  
S.-O. Hietala ◽  
P. Rooth
Keyword(s):  
Blood Flow ◽  
Fluorescence Microscopy ◽  
Cyclosporin A ◽  
Experimental Studies ◽  
Cortical Blood Flow ◽  
In Vivo Fluorescence ◽  
Renal Cortical Blood Flow ◽  
The Difference ◽  
Increased Blood Flow

In vivo fluorescence microscopy was used for experimental studies of the renal cortical microcirculation in normal mice and in mice pretreated with the nephrotoxic drug cyclosporin A. The cortical circulation was studied after i.v. infusions of a nonionic low osmolar contrast medium (iohexol) and after infusions of mannitol. All infusions produced marked effects on the distribution and velocity of cortical blood flow with no differences between iohexol and mannitol. The renal cortical blood flow was inhomogeneous regarding different capillaries and there was an initial rise in the number of capillaries with increased blood flow after infusions of both mannitol and iohexol. There was simultaneously an increased number of capillaries with decreased blood flow following all infusions. The decreased blood flow after infusion of iohexol was more pronounced when the animals had been pretreated with cyclosporin A. The difference was only significant (p < 0.05) during a short part of the observation period of 30 min, but it may indicate that kidneys previously exposed to cyclosporin A are more susceptible to infusions of iohexol.

SOMATOMEDIN PRODUCTION IN NORMAL ADULTS AND CIRRHOTIC PATIENTS

1977 ◽  
Vol 86 (2) ◽  
pp. 355-362 ◽  
Author(s):  
R. M. Schimpff ◽  
D. Lebrec ◽  
M. Donnadieu
Keyword(s):  
Blood Flow ◽  
Hepatic Blood Flow ◽  
Normal Subjects ◽  
Control Group ◽  
Cirrhotic Patients ◽  
The Mean ◽  
The Difference ◽  
The One ◽  
The Relationship ◽  
Normal Adults

ABSTRACT The somatomedin (SM) activity was measured in blood samples withdrawn simultaneously from hepatic (HV) and peripheral (PV) veins in 10 adult patients without liver disease (control group) and in 18 alcoholic patients with cirrhosis. SM activity in the control group was 1.27 ± 0.18 U/ml (mean ± sem) in the HV and 1.00 ± 0.17 U/ml in the PV. In patients with cirrhosis the SM activity was respectively 0.50 ± 0.05 and 0.56 ± 0.06 U/ml. SM activity was greater in the normal subjects than in the cirrhotic patients (P < 0.001 when SM activity measured in the HV, and P < 0.01 when measured in the PV). Close examination of the means of differences of SM activity between the HV and PV, showed that the differences were significantly different from 0 in control only (P < 0.02). At least, this difference (0.275 ± 0.093 U/ml) is greater (P < 0.01) than the one observed in cirrhotic patients (0.066 ± 0.036 U/ml). In 16 subjects, the hepatic blood flow was measured, and the mean hepatic SM activity production was estimated to be 398 ± 334 U/min in 6 subjects from the control group, and 16 U/min in 10 patients with cirrhosis. The difference is significant (P < 0.01). The relationship between SM activity, biochemical liver function parameters, hepatic blood flow and immunoreactive growth hormone were also studied. The results confirm that the liver is involved in serum somatomedin activity generation.

Atraumatic measuring of pulmonary capillary blood flow in dogs

1977 ◽  
Vol 42 (6) ◽  
pp. 980-984 ◽  
Author(s):  
R. E. Barrow ◽  
M. D. Shult
Keyword(s):  
Blood Flow ◽  
Nitrous Oxide ◽  
Capillary Blood ◽  
Capillary Blood Flow ◽  
Volume Changes ◽  
Pulmonary Capillary Blood Flow ◽  
Pulmonary Capillary ◽  
Pulmonary Capillary Blood ◽  
The Mean ◽  
Pulmonary Volume

Pulmonary capillary blood flow (Qc) was measured by a nitrous oxide uptake technique using a capacitance-plethysmograph to measure pulmonary volume changes. One hundred and four paired Qc and total cardiac outputs (Qt) were measured in 13 normal mongrel dogs. The mean Qc was 0.101 +/- 0.020 1-min -1-kg-1 while the mean Qt, measured by dye dilution, was 0.117 +/- 0.025 1-min-1-kg-1. This technique minimizes subject trauma and provides a method for repeated pulmonary capillary blood flow determinations in acute or chronic studies.

scholarly journals Evaluation of microcirculation disorders in patients with severe COVID-19 by nail bed capillaroscopy

2021 ◽  
Vol 18 (1) ◽  
pp. 27-36
Author(s):  
Е. Е. Ladozhskaya-Gapeenko ◽  
К. N. Khrapov ◽  
Yu. S. Polushin ◽  
I. V. Shlyk ◽  
I. V. Vartanova ◽  
...  
Keyword(s):  
Blood Flow ◽  
Blood Flow Rate ◽  
Organ Damage ◽  
Capillary Blood ◽  
Linear Velocity ◽  
Capillary Blood Flow ◽  
Nail Bed ◽  
Slowing Down ◽  
The Mean ◽  
Vital Microscopy

Microcirculation disorders caused by thrombosis are the most important factor determining the pathogenesis of organ damage in severe COVID-19 including the absence of obvious macrohemodynamic instability. However, there are very few publications demonstrating the results of intravital visualization of changes in the microcirculation system in this disease.The objective: to assess the state of microcirculation in patients with viral pneumonia associated with COVID-19 using nail bed microscopy.Subjects and methods. Eleven patients with COVID-19 were examined; they were admitted to the intensive care unit due to progressing acute respiratory failure. Vital microscopy of the microcirculatory bloodstream in the fingers’ nail bed was performed by admission and over time. When assessing microcirculation, the presence of aggregates in the lumen of capillaries and avascular zones, and the linear velocity of blood flow were taken into account. The results were summarized taking with the outcome consideration (6 people recovered, 5 died). Results. Microcirculation disorders were objectively confirmed in all patients. In 100% of cases, microaggregates were detected in the capillary lumen. The values of the mean linear velocity of capillary blood flow turned out to be extremely variable. However, the values of the maximum linear velocities of capillary blood flow in the patients who subsequently died were significantly lower versus survivors (190 μm/sec (135.5; 237) and 387 μm/sec (329.3; 407.5), p = 0.018). The irregularity of blood flow in the visualized field was revealed: when the value of the maximum linear velocity in some capillaries was less than 180 µm/sec, in others, disturbances in the form of pendulum-like movement were already noted. Further slowing down of the blood flow velocity led to the development of stasis and the formation of avascular zones.Conclusion. Impaired microcirculation (decreased blood flow rate in the capillaries, the presence of microaggregates and a lower number of perfused capillaries in the form of avascular zones) develops in all patients with severe COVID-19.

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