Two-cytochrome metabolic model for carotid body PtiO2 and chemosensitivity changes after hemorrhage

1989 ◽  
Vol 67 (1) ◽  
pp. 60-68 ◽  
Author(s):  
D. G. Buerk ◽  
P. K. Nair ◽  
W. J. Whalen
Keyword(s):  
Blood Pressure ◽  
Carotid Body ◽  
Metabolic Model ◽  
Arterial Blood ◽  
Blood Ph ◽  
Tissue Po2 ◽  
Blood Pressures ◽  
Microelectrode Measurements ◽  
Made In ◽  
Nerve Discharge

O2 microelectrode measurements were made in the cat carotid body (CB) at normal control blood pressures (C) and after hemorrhage (H) to reduce mean arterial blood pressure [C, 98.7 +/- 4.6 (SE) mmHg; H, 58.1 +/- 1.8; P less than 0.001; paired t test; n = 9 cats]. Mean tissue PO2 (PtiO2) was significantly lower (C, 78.4 +/- 3.0 Torr; H, 65.3 +/- 4.8; P less than 0.01). Except for two experiments with good autoregulation, the decrease in PtiO2 correlated with the reduction in blood pressure (r = 0.791, P less than 0.005). Measurements of O2 disappearance curves (DCs) and sinus nerve discharge (ND) were obtained after blood supply was occluded for 30–45 s (56 C DCs, 44 H DCs). Disappearance rates (dPO2/dt) were significantly slower after hemorrhage (C, -7.52 +/- 0.47 Torr/s; H, -6.60 +/- 0.44; P less than 0.01), decreasing by 0.656 Torr/s for each 10 Torr fall in PtiO2 (r = 0.626, P less than 0.05). Resting ND before occlusion increased during hypotension (11.6 +/- 2.9% of control, P less than 0.01) and correlated with the decrease in PtiO2 (r = -0.792, P less than 0.005). A computer simulation was performed for a two-cytochrome metabolic model with a second, low-O2-affinity oxidase in addition to normal oxidative metabolism. The effects of cat oxyhemoglobin and blood pH on the O2 DC measurement were also taken into account. The simulation for the two-cytochrome model was consistent with our experimental data and predicts reductions in blood flow and O2 metabolism with hypotension after hemorrhage that have similarities, as well as aspects that disagree, with previous reports in the literature.

Acidosis and blood epinephrine levels in hemorrhagic hypotension

1964 ◽  
Vol 206 (6) ◽  
pp. 1281-1284 ◽  
Author(s):  
Thomas D. Darby ◽  
Daniel T. Watts
Keyword(s):  
Blood Pressure ◽  
Venous Blood ◽  
Assay Method ◽  
Central Venous ◽  
Arterial Blood ◽  
Blood Ph ◽  
Left Femoral Artery ◽  
Blood Pressures ◽  
Hemorrhage Volume

Dogs were anesthetized with pentobarbital 30 mg/kg. Cannulas were placed for measurement of arterial and central venous blood pressures. The left femoral artery was cannulated and attachment was made to a reservoir set to maintain arterial blood pressure at 40 mm Hg. Blood pH, pCO2, and pO2 were obtained concomitantly with measurements of blood epinephrine levels utilizing the rat uterus assay method. Rapid hemorrhage to 40 mm Hg blood pressure elicited increments in blood epinephrine levels that closely followed the development of uncompensated acidosis. Correction of the acidosis by intravenous administration of tromethamine or sodium bicarbonate at a blood pressure of 40 mm Hg reduced the blood epinephrine levels by at least 50%, markedly improved cardiac function, increased hemorrhage volume, reduced respiratory rate, and, paradoxically, increased arterial pO2. In vitro studies showed that acidosis did not inhibit destruction of epinephrine added to blood. It was concluded that the adrenal gland is stimulated by acidosis to secrete epinephrine. This stimulation is an important source of blood epinephrine during periods of hypotension associated with shock.

Validity of Neonatal Blood Pressure Obtained By The Manometric Method

PEDIATRICS ◽  
1973 ◽  
Vol 52 (2) ◽  
pp. 293-296
Author(s):  
Rosemary D. Leake ◽  
Paul R. Williams ◽  
William Oh
Keyword(s):  
Blood Pressure ◽  
Neonatal Intensive Care ◽  
Umbilical Artery ◽  
Neonatal Intensive Care Units ◽  
Arterial Blood ◽  
Direct Recording ◽  
Blood Pressures ◽  
Manometric Method ◽  
Neonatal Blood ◽  
Precise Relationship

In neonatal intensive care units where direct arterial blood pressures obtained via a transducer are unavailable, a fluid-filled spinal manometer has been used. The latter method is practical and convenient although its validity has not been confirmed. This study is designed to establish the precise relationship between the blood pressure obtained by the manometric method and by direct recording via the arterial transducer. Materials and Methods Eleven infants with umbilical artery catheters in place 1 to 2 cm above the diaphragm were selected for the study. In all instances, the arterial catheters were placed for clinical management of various illnesses.

Validity of phonoarteriographic blood pressures during rest and exercise

1964 ◽  
Vol 19 (6) ◽  
pp. 1219-1233 ◽  
Author(s):  
Joseph A. Mastropaolo ◽  
Jeremiah Stamler ◽  
David M. Berkson ◽  
Hans U. Wessel ◽  
Walter E. Jackson
Keyword(s):  
Blood Pressure ◽  
Fitness Testing ◽  
Physical Effort ◽  
Indirect Measurements ◽  
Arterial Blood ◽  
Hearing Acuity ◽  
Pulse Sound ◽  
Blood Pressures ◽  
Pressure Record ◽  
Rest And Exercise

A modification of the auscultatory blood pressure method, the phonoarteriogram, was developed. The innovated method essentially is a modified amplifying stethoscope. The pressure in the cuff is recorded from a pressure transducer, and the systolic and diastolic criteria are recorded from a microphone. The phonoarteriogram gives the advantages of a permanent record, includes pulse rate and pulse sound data, is not affected by hearing acuity, permits determinations often denied using auscultation in high ambient noise and exercise conditions, and eliminates observer bias. Three hundred and forty resting determinations and 218 exercise determinations on 60 subjects indicated good agreement between the phonoarteriogram and auscultation. In 50 systolic and diastolic intra-arterial determinations before compression of the cuff, during rest and exercise from one subject, the phonoarteriogram was as valid as auscultation. In 56 intra-arterial determinations during deflation of the cuff, i.e., simultaneous with the indirect measurements, during rest and exercise from a second subject, the phonoarteriogram was less fallible than auscultation, particularly during exercise. Phonoarteriograms are valid, reliable, and objective blood pressure record blood pressure determination; auscultatory blood pressure; intra-arterial blood pressure; physical fitness testing; ausculation; effort or physical effort; exercise; exertion; fatigue; methods, physiological; instrumentation; pulse; work Submitted on January 16, 1964

scholarly journals Wavelet Autoregulation Monitoring Identifies Blood Pressures Associated With Brain Injury in Neonatal Hypoxic-Ischemic Encephalopathy

2021 ◽  
Vol 12 ◽  
Author(s):  
Xiuyun Liu ◽  
Aylin Tekes ◽  
Jamie Perin ◽  
May W. Chen ◽  
Bruno P. Soares ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Brain Injury ◽  
Therapeutic Hypothermia ◽  
Near Infrared ◽  
Brain Regions ◽  
Hypoxic Ischemic Encephalopathy ◽  
Volume Index ◽  
Arterial Blood ◽  
Blood Pressures ◽  
Ischemic Encephalopathy

Dysfunctional cerebrovascular autoregulation may contribute to neurologic injury in neonatal hypoxic-ischemic encephalopathy (HIE). Identifying the optimal mean arterial blood pressure (MAPopt) that best supports autoregulation could help identify hemodynamic goals that support neurologic recovery. In neonates who received therapeutic hypothermia for HIE, we hypothesized that the wavelet hemoglobin volume index (wHVx) would identify MAPopt and that blood pressures closer to MAPopt would be associated with less brain injury on MRI. We also tested a correlation-derived hemoglobin volume index (HVx) and single- and multi-window data processing methodology. Autoregulation was monitored in consecutive 3-h periods using near infrared spectroscopy in an observational study. The neonates had a mean MAP of 54 mmHg (standard deviation: 9) during hypothermia. Greater blood pressure above the MAPopt from single-window wHVx was associated with less injury in the paracentral gyri (p = 0.044; n = 63), basal ganglia (p = 0.015), thalamus (p = 0.013), and brainstem (p = 0.041) after adjustments for sex, vasopressor use, seizures, arterial carbon dioxide level, and a perinatal insult score. Blood pressure exceeding MAPopt from the multi-window, correlation HVx was associated with less injury in the brainstem (p = 0.021) but not in other brain regions. We conclude that applying wavelet methodology to short autoregulation monitoring periods may improve the identification of MAPopt values that are associated with brain injury. Having blood pressure above MAPopt with an upper MAP of ~50–60 mmHg may reduce the risk of brain injury during therapeutic hypothermia. Though a cause-and-effect relationship cannot be inferred, the data support the need for randomized studies of autoregulation and brain injury in neonates with HIE.

scholarly journals Study of Inter-arm Variation of Blood Pressure in Normal and Diabetic In-dividual in Out Patient Department of Nepal Medical College

2021 ◽  
Vol 1 (1) ◽  
pp. 12-16
Author(s):  
Pragati Poudyel ◽  
Seerina Adhikari
Keyword(s):  
Blood Pressure ◽  
Cuff Pressure ◽  
Developed Countries ◽  
Sitting Posture ◽  
Medical College ◽  
Arterial Blood ◽  
Measure Blood Pressure ◽  
Normal Individuals ◽  
Blood Pressures ◽  
The Comparative Study

 Introduction: Growing incidence of hypertension and its significant association with diabetes mellitus are being observed in both developing and developed countries around globe. Scanty literature is available about the comparative study of inter-arm variation of blood pressure in normal individuals and diabetic among Nepalese population. This research was performed to determine extent of inter-arm variation in normal individuals and diabetics. Methods: A descriptive observational study was carried out from 2013 January to 2014 January in a tertiary level teaching hospital of Nepal. After taking the consent and giving necessary instructions, blood pressures were measured in both the arms one after another in sitting posture using mercurial sphygmomanometer and Littman cardiosonic stethoscope. Arterial blood pressure was measured by palpatory method followed by auscultatory method The cuff pressure at which the tap sound were first perceived was noted as systolic blood pressure (SBP). Similarly, diastolic blood pressure (DBP) was noted at the point where the sound disappeared. Results: A total of 120 volunteers between ages of 40-80 years were studied. Highly significant inter-arm variation of both SBP and DBP was found in diabetics as compared to normal (p<0.01). Highly significant inter-arm variation was found in diabetic male and female as compared to their normal counter parts (p<0.01). Conclusion: This study showed that there was significant inter-arm variation of SBP and DBP in diabetic and normal individual. So, this study encourages to measure blood pressure (BP) in both arms for proper treatment planning of an individuals.

scholarly journals Acute Hemodynamic Changes Associated with Zumba and ZOCA Dance Exercises among Females of Selected Gyms in Lusaka, Zambia

2020 ◽  
Vol 2 (1) ◽  
pp. 84-91
Author(s):  
Chanda Grace Chisunka ◽  
◽  
Gibson Sijumbila ◽  
Fastone Goma ◽  
◽  
...  
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Systolic Blood Pressure ◽  
Hemodynamic Changes ◽  
Aerobic Dance ◽  
Arterial Blood ◽  
Effective Dynamic ◽  
Blood Pressure Monitors ◽  
Blood Pressures

Background: Dynamic exercises are known to elicit hemodynamic changes such as an increase in arterial blood pressure and heart rate. Zumba and ZOCA are part of a fast growing group of dance fitness programmes designed to provide a cardiovascular dynamic workout. Despite their growing popularity, very few studies have been done to provide knowledge regarding the hemodynamic changes associated with these exercises. Methods: Case study in which 27 females took part in either a Zumba or ZOCA class. Using digital blood pressure monitors, recordings of blood pressure and heart rate were taken, firstly, before commencement of the exercise, secondly, after 30 minutes after exercise and thirdly, at the end of the class.Results: Mean baseline blood pressures were 118 (SD = 14) mmHg and 77 (SD = 7) mmHg, systolic and diastolic blood pressures, respectively. After 30 minutes of dancing, mean systolic blood pressure increased to 130 (SD = 19) mmHg (p˂ 0.05) while diastolic blood pressureonly rose to an average of 80 (SD = 8) mmHg (p˃ 0.05). At the end of the class (after the cool down phase) mean systolic blood pressure reduced to 109 (SD = 13) mmHg (p˂0.05) while diastolic blood pressure reduced to 74(SD = 12) mmHg (p˂ 0.05). Conclusions: Zumba and ZOCA elicited significant hemodynamic changes that can be attributed to these exercises stimulating the cardiovascular regulatory mechanisms (e.g central command and exercise-pressor) sufficiently and hence resulting in autonomic adjustmentsthat were concurrent with effective dynamic exercise. Keywords: Blood Pressure, Heart Rate, Aerobic, Dance Exercise

Some factors affecting tissue Po2 in the carotid body

1975 ◽  
Vol 39 (4) ◽  
pp. 562-566 ◽  
Author(s):  
W. J. Whalen ◽  
P. Nair
Keyword(s):  
Blood Flow ◽  
Arterial Pressure ◽  
Carotid Body ◽  
Discharge Rate ◽  
Reduced Pressure ◽  
Factors Affecting ◽  
Arterial Blood ◽  
Nervous System Activity ◽  
Tissue Po2 ◽  
Anesthetized Cat

In the carotid body (CB) of the anesthetized cat tissue Po2 (Pto2) measured with a micro O2 electrode averaged about 65 mmHg at normal arterial pressure (mean = 96 mmHg). Pto2 correlated significantly with the hematocrit of the arterial blood but not with % saturation. When arterial pressure was reduced (mean = 58 mmHg) by bleeding Pto2 fell significantly. Phentolamine injection (1 mg/kg iv) at the reduced pressure caused Pto2 to rise significantly. At normal arterial pressure blowing moistened O2 over the CB did not affect Pto2 if the electrode tip was about 90 mum into the CB. At a reduced pressure (and blood flow) the sensitive depth increased to about 301 mum, and to about 600 mum when flow was stopped. We concluded that a) the increased chemoceptor discharge usually seen with hemorrhage is due to reduced Pto2; b) the reduction in Pto2 is probably due to reduced blood flow which is, in turn, caused partly, at least, by sympathetic nervous system activity; c) O2 content, rather than Po2, may determine chemoreceptor discharge rate; and d) there are no barriers in the CB which are impermeable to O2.

Cardiovascular responses to severe hypercapnia of short duration

1964 ◽  
Vol 207 (3) ◽  
pp. 634-640 ◽  
Author(s):  
Emmett S. Manley ◽  
Clinton B. Nash ◽  
R. A. Woodbury
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Short Duration ◽  
Cardiovascular Responses ◽  
Myocardial Contraction ◽  
Contractile Force ◽  
Sympathetic Activation ◽  
Pentobarbital Anesthesia ◽  
Arterial Blood ◽  
Blood Ph

Dogs under pentobarbital anesthesia were employed in an investigation of the effect of abrupt, severe hypercapnia upon blood pressure, heart rate, and force of myocardial contraction. Electrocardiographic activity and arterial blood pH were also monitored. Hypercapnia was induced for 10-min periods with 15 and 30% CO2 in oxygen. The studies were undertaken in nontreated animals and animals treated with atropine, reserpine, chlorisondamine, P-286, or bilateral adrenalectomy. Severe hypercapnia was shown to be depressant to the cardiovascular parameters evaluated, but blood pressure and contractile force normally demonstrated compensation to this depression. Parasympathetic blockade with atropine did not reduce the depression observed in the nontreated dogs during hypercapnia. Results obtained with other pretreated animals indicate that compensation occurs primarily via sympathetic activation. Adrenal activation may assume importance in compensation to 30% CO2, but intact adrenals were not necessary for survival during hypercapnia. No arrhythmias (excluding bradycardia) were observed during or immediately following exposure to either concentration of CO2.

scholarly journals External Abdominal Aortic Compression: A Study of a Resuscitation Manoeuvre for Postpartum Haemorrhage

1994 ◽  
Vol 22 (5) ◽  
pp. 571-575 ◽  
Author(s):  
D. P. Riley ◽  
R. W. Burgess
Keyword(s):  
Blood Pressure ◽  
Postpartum Haemorrhage ◽  
Aortic Occlusion ◽  
Medical Assistance ◽  
Arterial Blood ◽  
Abdominal Aortic ◽  
Life Threatening ◽  
Blood Pressures ◽  
A Prospective Study ◽  
And Control

External aortic compression is an emergency manoeuvre proposed to reduce postpartum haemorrhage and permit time for resuscitation and control of bleeding. To assess this technique, a prospective study was performed on twenty normal non-bleeding parturients. The abdominal aorta was compressed by firm pressure with a closed fist just above the umbilicus. Leg and arm arterial blood pressures were measured and femoral artery pulsation felt before, during and after compression. Leg blood pressure was completely obliterated in 55% and significantly reduced (P < 0.01) in a further 10% of subjects. All of these subjects with reduced or absent leg blood pressure also had obliteration of the femoral pulse with compression. Systemic arterial blood pressure was not significantly elevated by successful aortic occlusion. Discomfort with the manoeuvre was significantly increased (P < 0.05) in the group of subjects that had successful aortic occlusion. It is recommended that external aortic compression be considered in severe life-threatening postpartum haemorrhage, particularly during stabilisation or transport of the patient. This simple manoeuvre may be used as an adjunct to other measures and could prove of benefit, especially in locations or situations where advanced medical assistance is geographically or temporally removed.

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