Indomethacin compromises hemodynamics during positive-pressure ventilation, independently of prostanoids

1993 ◽  
Vol 74 (4) ◽  
pp. 1672-1678 ◽  
Author(s):  
D. D. Malcolm ◽  
J. L. Segar ◽  
J. E. Robillard ◽  
S. Chemtob
Keyword(s):  
Blood Flow ◽  
Cardiac Output ◽  
Cerebral Blood Flow ◽  
Airway Pressure ◽  
Regional Blood Flow ◽  
Blood Gases ◽  
Positive Pressure ◽  
Organ Blood Flow ◽  
Mean Airway Pressure ◽  
Airway Pressures

We examined whether prostanoids contribute to the impaired cardiac function and decrease in regional blood flow induced by increasing mean airway pressure. Using microspheres, we measured cardiac output and major organ blood flow and assayed prostaglandin E2, 6-ketoprostaglandin F1 alpha, and thromboxane B2 in blood at mean airway pressures of 5–25 cmH2O in mechanically ventilated newborn piglets treated with ibuprofen (40 mg/kg, n = 6), indomethacin (0.3 mg/kg, n = 6), or vehicle (n = 6). Blood gases and pH were stable throughout the experiments. Prostanoid levels remained constant with increasing mean airway pressure in vehicle-treated pigs and were unchanged by indomethacin. However, ibuprofen decreased the prostanoid levels at all mean airway pressures studied (P < 0.01). As ventilatory pressure was progressively increased, cardiac output decreased gradually and similarly by 42–45% (P < 0.05) in all groups. At the highest mean airway pressure, blood flow decreased to the kidneys by 37–57%, to the ileum by 58–74%, and to the colon by 53–71% (P < 0.05) in all groups. Cerebral blood flow remained constant at all ventilatory pressures regardless of the treatment. There was no difference in cardiac output and regional hemodynamics between ibuprofen- and vehicle-treated animals. However, after indomethacin, ileal blood flow at the higher ventilatory pressures was 41–46% lower and cerebral blood flow at all mean airway pressures was 14–25% lower than after the other treatments (P < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Continuous Airway Pressure Breathing With the Head-Box in the Newborn Lamb: Effects on Regional Blood Flows

PEDIATRICS ◽  
1977 ◽  
Vol 59 (6) ◽  
pp. 858-864
Author(s):  
G. Gabriele ◽  
C. R. Rosenfeld ◽  
D. E. Fixler ◽  
J. M. Wheeler
Keyword(s):  
Blood Flow ◽  
Cardiac Output ◽  
Airway Pressure ◽  
Left Ventricular Pressure ◽  
Blood Gases ◽  
Ocular Blood Flow ◽  
Left Ventricular ◽  
Positive Pressure ◽  
Blood Flows ◽  
Arterial Blood

Continuous airway pressure delivered by a head-box is an accepted means of treating clinical hyaline membrane disease. To investigate hemodynamic alterations resulting from its use, eight newborn lambs, 1 to 6 days of age, were studied at 6 and 11 mm Hg of positive pressure, while spontaneously breathing room air. Organ blood flows and cardiac output were measured with 25 µ-diameter radioactive microspheres. Heart rate, left ventricular pressure, and arterial blood gases did not change during the study. Jugular venous pressures increased from 6.4 mm Hg to 18.6 and 24.2 mm Hg at 6 and 11 mm Hg, respectively (P &lt; .005). Cardiac output decreased approximately 20% at either intrachamber pressure setting. Renal blood flow fell 21% at 11 mm Hg. No significant changes in blood flow were found in the brain, gastrointestinal tract, spleen, heart, or liver when compared to control flows. Of particular interest was the finding of a 28% reduction in ocular blood flow at 6 mm Hg and 52% at 11 mm Hg. From these results, we conclude that substantial cardiovascular alterations may occur during the application of head-box continuous airway pressure breathing, including a significant reduction in ocular blood flow.

scholarly journals Evaluation of a Humidified Nasal High-Flow Oxygen System, Using Oxygraphy, Capnography and Measurement of Upper Airway Pressures

2011 ◽  
Vol 39 (6) ◽  
pp. 1103-1110 ◽  
Author(s):  
J. E. Ritchie ◽  
A. B. Williams ◽  
C. Gerard ◽  
H. Hockey
Keyword(s):  
Healthy Volunteers ◽  
Airway Pressure ◽  
Gas Flow ◽  
Air Entrainment ◽  
High Flow ◽  
Positive Pressure ◽  
Mean Airway Pressure ◽  
Flow Rates ◽  
Oxygen Fraction ◽  
Airway Pressures

In this study, we evaluated the performance of a humidified nasal high-flow system (Optiflow™, Fisher and Paykel Healthcare) by measuring delivered FiO2 and airway pressures. Oxygraphy, capnography and measurement of airway pressures were performed through a hypopharyngeal catheter in healthy volunteers receiving Optiflow™ humidified nasal high flow therapy at rest and with exercise. The study was conducted in a non-clinical experimental setting. Ten healthy volunteers completed the study after giving informed written consent. Participants received a delivered oxygen fraction of 0.60 with gas flow rates of 10, 20, 30, 40 and 50 l/minute in random order. FiO2, FEO2, FECO2 and airway pressures were measured. Calculation of FiO2 from FEO2 and FECO2 was later performed. Calculated FiO2 approached 0.60 as gas flow rates increased above 30 l/minute during nose breathing at rest. High peak inspiratory flow rates with exercise were associated with increased air entrainment. Hypopharyngeal pressure increased with increasing delivered gas flow rate. At 50 l/minute the system delivered a mean airway pressure of up to 7.1 cmH2O. We believe that the high gas flow rates delivered by this system enable an accurate inspired oxygen fraction to be delivered. The positive mean airway pressure created by the high flow increases the efficacy of this system and may serve as a bridge to formal positive pressure systems.

Cardiovascular adjustments to laboratory diving in beavers and nutria

1982 ◽  
Vol 242 (5) ◽  
pp. R434-R440
Author(s):  
T. McKean
Keyword(s):  
Blood Flow ◽  
Cardiac Output ◽  
Regional Blood Flow ◽  
Castor Canadensis ◽  
Venous Blood ◽  
Regional Distribution ◽  
Blood Gases ◽  
Myocastor Coypus ◽  
Recovery From Anesthesia ◽  
Rate Of Decline

Beavers (Castor canadensis) and nutria (Myocastor coypus) were anesthetized with halothane and catheters placed in the left ventricle, aorta and pulmonary artery, right ventricle or right atrium. The animals were strapped to a board and following recovery from anesthesia the following measurements were taken: regional distribution of blood flow, cardiac output, O2 consumption, arterial and venous blood gases, and pH. The animal was then immersed in 15-20 degrees C water for up to 2.75 min (nutria) or 4 min (beaver) and the measurements repeated. Heart rate and cardiac output decreased by 80 and 75%, respectively. Arterial and venous oxygen partial pressure and content fell as did pH whereas CO2 pressures rose during diving. Oxygen consumption at rest was 124 and 102% of that predicted on the basis of body mass for the beaver and nutria, respectively. Rate of decline of O2 stores during diving decreased by 93% in beavers and 89% in nutria compared to the predive value. Regional blood flow decreased to all organs except the adrenals, heart, and lungs. Blood flow to the brain increased during diving.

Cardiovascular responses to graded degrees of hypoxaemia in the llama fetus

1995 ◽  
Vol 7 (3) ◽  
pp. 549 ◽  
Author(s):  
AJ Llanos ◽  
RA Riquelme ◽  
FA Moraga ◽  
G Cabello ◽  
JT Parer
Keyword(s):  
Blood Flow ◽  
Cardiac Output ◽  
Cerebral Blood Flow ◽  
Cardiovascular Response ◽  
Blood Gases ◽  
Cardiovascular Responses ◽  
Fetal Sheep ◽  
Severe Hypoxaemia ◽  
The Central Nervous System ◽  
Blood Flow Redistribution

The fetal llama exposed to an intense degree of hypoxaemia did not increase cerebral blood flow, but showed a marked peripheral vasoconstriction. The same cardiovascular response is observed in fetal sheep submitted to a extremely severe hypoxaemia, when the initial compensatory vasodilatory mechanisms in brain and heart fail. To investigate whether the fetal llama responses to acute hypoxaemia are adaptive, or whether they are the result of a breakdown of mechanisms of blood flow redistribution that favours the central nervous system, we studied seven fetal llamas (0.6-0.7 of gestation) chronically-catheterized during 1 h of graded and progressive hypoxaemia. Fetal ascending aorta blood gases and fetal cardiac output and its distribution (radiolabelled-microspheres) were measured after 60 min of normoxaemia (B) and at the end of 20 min (H20), 40 min (H40) and 60 min (H60) of hypoxaemia. Data were analysed by ANOVA and Newman-Keuls tests. Each treatment resulted in a lower (P < 0.05) percentage of haemoglobin saturation than hypoxaemia; H40 was lower than H20, and H60 was lower than H20 and H40. No statistical difference was observed among treatments for cardiac output or cerebral blood flow. These results demonstrate that fetal cardiac output and brain blood flow are maintained at all degrees of hypoxaemia, indicating that these cardiovascular responses are an adaptive response in the llama fetus, rather than an index of cardiorespiratory decompensation.

Regional blood flows measured in Mongolian gerbil by a modified microsphere method

1982 ◽  
Vol 242 (6) ◽  
pp. H990-H995
Author(s):  
M. Matsumoto ◽  
K. Kimura ◽  
A. Fujisawa ◽  
T. Matsuyama ◽  
T. Asai ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Left Ventricle ◽  
Regional Cerebral Blood Flow ◽  
Regional Blood Flow ◽  
Reference Sample ◽  
Organ Blood Flow ◽  
Regional Cerebral Blood ◽  
Stroke Research ◽  
Microsphere Method

Regional blood flow to major organs and regional cerebral blood flow were determined in seven anesthetized male gerbils by a modified microsphere method. Carbonized microspheres, 15 micrometers in diameter and labeled with 85Sr or 141Ce, were injected into the left ventricle by cardiac puncture through the closed thorax, and reference samples of known volume were withdrawn from tail-artery cannula. No significant hemodynamic alterations were observed during microsphere administration, and extraction of 15-micrometers microspheres by the pulmonary or systemic capillary beds was nearly 100%. The adequacy of mixing of microspheres in the left ventricle was also validated. The absolute regional blood flow to various organs and regional cerebral blood flow were expressed in terms of milliliters per minute per gram tissue weight, and the values mostly agreed with those reported previously in rats. The results indicate that the reference sample method can be applied to the gerbil. This method should allow the gerbil, which is an animal widely used in stroke research, to be conveniently used for hemodynamic studies when organ blood flow and regional cerebral blood flow are necessary.

Effects of intra-atrial injection of colored microspheres on systemic hemodynamics and regional blood flow in rats

1994 ◽  
Vol 266 (5) ◽  
pp. H1910-H1917 ◽  
Author(s):  
N. Kobayashi ◽  
K. Kobayashi ◽  
K. Kouno ◽  
S. Horinaka ◽  
S. Yagi
Keyword(s):  
Blood Flow ◽  
Cardiac Output ◽  
Blood Sample ◽  
Regional Blood Flow ◽  
Fluid Replacement ◽  
Male Rats ◽  
Organ Blood Flow ◽  
Hemodynamic Effects ◽  
Sprague Dawley ◽  
Sample Technique

The hemodynamic effects of various numbers of colored nonradioactive microspheres (CMS) and those of accumulation of CMS caused by multiple sequential injection were evaluated in 51 Sprague-Dawley male rats. CMS (15 microns) were injected into the left atrium. Regional blood flow and cardiac output were evaluated using the reference blood sample technique. Ficoll-70 was given after each blood sample withdrawal as a fluid replacement. A bolus injection of < or = 1,000,000 CMS caused no significant hemodynamic disturbances. Amounts of 500,000 CMS can be repeatedly injected up to four times (cumulative dose of 2,000,000 CMS) without producing any adverse hemodynamic effects. The values of cardiac output obtained with the CMS technique were correlated well (r = 0.971, P < 0.0001) with those obtained with electromagnetic flow probes. An excellent reproducibility of organ blood flow was observed after four sequential injections of 500,000 CMS. This study establishes the limits of CMS that can be injected into the rat without inducing hemodynamic changes and also suggests that the CMS technique can be employed to evaluate cardiac output and regional blood flow precisely and repeatedly.

THE EFFECT OF A CHRONIC CATHETERIZATION PROCEDURE ON REGIONAL BLOOD FLOW AND CARDIO-PULMONARY PARAMETERS IN THE LABORATORY RAT

1986 ◽  
Vol 66 (2) ◽  
pp. 553-557
Author(s):  
D. D. KITTS ◽  
S. J. YEE ◽  
A. L. SCHAEFER
Keyword(s):  
Blood Flow ◽  
Cardiac Output ◽  
Key Words ◽  
Regional Blood Flow ◽  
Blood Gases ◽  
Blood Collection ◽  
Blood Flows ◽  
Regional Blood Flows ◽  
Anaesthetized Rat ◽  
Catheterization Procedure

A blood collection technique for conscious, catheterized, unrestrained rats was standardized. Regional blood flows to the heart, brain and viscera were significantly lower in the anaesthetized rat and followed the decline observed in cardiac output. A recovery of all measured physiological parameters to stable levels required approximately 20 min. Key words: Chronically catheterized rats, anaesthesia, blood gases, regional blood flow

Total and regional cerebral blood flow during moderate and severe exercise in miniature swine

1976 ◽  
Vol 40 (2) ◽  
pp. 191-195 ◽  
Author(s):  
D. L. Foreman ◽  
M. Sanders ◽  
C. M. Bloor
Keyword(s):  
Heart Rate ◽  
Blood Flow ◽  
Cardiac Output ◽  
Cerebral Blood Flow ◽  
White Matter ◽  
Regional Blood Flow ◽  
Aortic Pressure ◽  
Miniature Swine ◽  
Regional Flow ◽  
Severe Exercise

To determine the influence of exercise on cerebral blood flow, we ran 14 swine at 3–6 mph and at 0–10% grades on a treadmill for 30 min at moderate and severe levels of exercise. Measuring heart rate, cardiac output, and aortic pressure via implanted probes, we injected 15-mum radiolabeled microspheres via the left atrium before and during exercise. We measured their distribution by gamma spectrometry, determining total cerebral blood flow, regional blood flow, and ratio of flow to gray and white matter. Heart rate, cardiac output, and aortic pressure rose progressively with increasing exercise. Total cerebral flow resembled that reported in humans, i.e., it did not change significantly with exercise. Regional flow distribution also failed to change significantly with exercise. The ratio of gray to white matter flow did not change except to the cerebellum where it rose significantly from resting values at both moderate and severe exercise. Gray matter received more flow than white matter during all three conditions of observation. Cerebral blood flow was remarkably constant during even severe exercise.

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