Relative responses of aortic body and carotid body chemoreceptors to hypotension

1980 ◽  
Vol 48 (5) ◽  
pp. 781-788 ◽  
Author(s):  
S. Lahiri ◽  
T. Nishino ◽  
A. Mokashi ◽  
E. Mulligan
Keyword(s):  
Oxygen Tension ◽  
Carotid Body ◽  
Discharge Rate ◽  
Arterial Oxygen Tension ◽  
Blood Gases ◽  
Arterial Oxygen ◽  
Carotid Chemoreceptors ◽  
Arterial Blood ◽  
Carotid Body Chemoreceptors ◽  
Pressure Changes

Responses to acute arterial blood pressure changes of a single or a few chemoreceptor afferents from the aortic body and carotid body at constant arterial blood gases and pH were measured in 16 adult cats. During normocapnic normoxia and moderate hypoxia (arterial oxygen tension of 60 Torr) an induced hypotension of 80 Torr increased strikingly the discharge rate of all aortic chemoreceptors but not of most carotid chemoreceptors; hypotension down to the level of 50 Torr stimulated most carotid chemoreceptors only slightly. Hyperoxia eliminated the stimulatory effect of this degree of hypotension on carotid chemoreceptors; it did not affect aortic chemoreceptors to the same extent. Hypoxia augmented the effect on aortic chemoreceptors more than the effect on carotid chemoreceptors. Thus the effect of hypotension was dependent on arterial oxygen tension. The greater effect of hypotension on aortic body chemoreceptor activity indicates a greater normal circulatory constraint for the aortic body. Accordingly, aortic chemoreceptors are more suited to monitor circulatory changes in O2 flow, and carotid chemoreceptors are more suited to monitor arterial gas pressure changes due to respiration.

Aortic body chemoreceptor responses to changes in PCO2 and PO2 in the cat

1979 ◽  
Vol 47 (4) ◽  
pp. 858-866 ◽  
Author(s):  
S. Lahiri ◽  
E. Mulligan ◽  
T. Nishino ◽  
A. Mokashi
Keyword(s):  
Carbon Dioxide ◽  
Discharge Rate ◽  
Arterial Oxygen Tension ◽  
Blood Gases ◽  
Carbon Dioxide Tension ◽  
Steady States ◽  
Arterial Oxygen ◽  
Arterial Blood ◽  
Discharge Rates ◽  
End Tidal

Responses of aortic chemoreceptor afferents to a range of arterial carbon dioxide tension (Paco2) changes at various levels of arterial oxygen tension (Pao2) were investigated in 18 cats anesthetized with alpha-chloralose and maintained at 38 degrees C. Aortic chemoreceptor activity, end-tidal oxygen pressure, end-tidal carbon dioxide pressure, and arterial blood pressure were continuously monitored. Arterial blood gases were measured in steady states. Single or a few clearly identifiable afferents were studied during changes and steady states of Pao2 and Paco2. All the aortic chemoreceptor afferent discharge rates increased with Paco2 increases from hypercapnia (10–15 Torr) to normocapnia and moderate hypercapnia (30–50 Torr) and with Pao2 decreases from above 400 to 30 Torr. Hypoxia augmented the response to Paco2 most effectively in the range of 10–40 Torr. At any Pao2, the discharge rate reached a plateau with sufficient intensity of hypercapnia. The Paco2 stimulus threshold at a Pao2 of 440 Torr was about 15 Torr, and at a Pao2 of 60 Torr it was 10 Torr. In the transition from hypocapnia to hypercapnia, responses increased gradually, usually without an overshoot. The steady-state responses to Paco2 of the majority of aortic chemoreceptors resembled those of carotid chemoreceptors. The responses of both receptors can be attributed to the same basic type of mechanism.

PERIODIC BREATHING AND APNEA IN PRETERM INFANTS. II. HYPOXIA AS A PRIMARY EVENT

PEDIATRICS ◽  
1972 ◽  
Vol 50 (2) ◽  
pp. 219-228
Author(s):  
Henrique Rigatto ◽  
June P. Brady
Keyword(s):  
Preterm Infants ◽  
Oxygen Tension ◽  
Minute Ventilation ◽  
Arterial Oxygen Tension ◽  
Blood Gases ◽  
Periodic Breathing ◽  
Capillary Blood ◽  
Arterial Oxygen ◽  
Primary Event ◽  
The Relationship

We studied nine healthy preterm infants during the first 35 days of life to define the relationship between periodic breathing, apnea, and hypoxia. For this purpose we compared ventilation/apnea (V/A), minute ventilation, and alveolar and capillary blood gases during periodic breathing induced by hypoxia and during spontancous periodic breathing in room air. We induced periodic breathing by giving the baby in sequence 21, 19, 17, and 15% O2 to breathe for 5 minutes each, and also by giving 21, 15, and 21% O2. We measured ventilation with a nosepiece and a screen flowmeter. With a decrease in arterial oxygen tension, preterm infants (1) hypoventilated, (2) breathed periodically more frequently, and (3) showed a decrease in V/A due to an increase in the apneic interval. In one baby this led to apnea lasting 30 seconds. These findings support our hypothesis that preterm infants breathing periodically hypoventilate and suggest that hypoxia may be a primary event leading to periodic breathing and apnea.

Continuous Monitoring of Arterial Oxygen Tension Using a Catheter-Tip Polarographic Electrode in Infants

PEDIATRICS ◽  
1976 ◽  
Vol 57 (2) ◽  
pp. 244-250
Author(s):  
M. Conway ◽  
G. M. Durbin ◽  
D. Ingram ◽  
N. McIntosh ◽  
D. Parker ◽  
...  
Keyword(s):  
Oxygen Tension ◽  
Continuous Monitoring ◽  
Newborn Infants ◽  
Arterial Oxygen Tension ◽  
Oxygen Electrode ◽  
Arterial Oxygen ◽  
Respiratory Illnesses ◽  
Arterial Blood ◽  
Reliable Instrument ◽  
Catheter Tip

An oxygen electrode mounted in the tip of an umbilical artery catheter was used in 36 newborn infants with severe respiratory illnesses, 28 of whom survived. Thirty-seven electrodes were used. The median age at insertion was 4 hours (range, 30 minutes to 122 hours). Three electrodes failed to work and they were removed or replaced, and two could not be properly evaluated. Thirty-two electrodes functioned satisfactorily for 10 to 190 hours (mean, 75 hours) after a one-point calibration against blood sampled through the catheter. Twenty-two did not need recalibrating before they were removed after 10 to 190 hours (mean, 88 hours). Four of the remaining ten electrodes were recalibrated once after 33 to 97 hours and then functioned until removed 15 to 55 hours later. The other six electrodes failed after 32 to 105 hours (mean, 49 hours). Complications were few. A total of 356 arterial blood samples, obtained after the initial calibration and before any recalibration was necessary, gave a correlation coefficient of 0.93 (P < .0001) against an independent system for measuring arterial oxygen tension (Pao2) (Radiometer Type E.5046 oxygen electrode). We conclude that the catheter-tip electrode is a safe and reliable instrument for continuously recording Pao2 in newborn infants which much simplifies the management of serious respiratory illnesses.

Relative latency of responses of chemoreceptor afferents from aortic and carotid bodies

1980 ◽  
Vol 48 (2) ◽  
pp. 362-369 ◽  
Author(s):  
S. Lahiri ◽  
T. Nishino ◽  
E. Mulligan ◽  
A. Mokashi
Keyword(s):  
Blood Pressure ◽  
Arterial Blood Pressure ◽  
Carotid Body ◽  
Blood Gases ◽  
Unexpected Result ◽  
Blood Gas ◽  
Arterial Blood Gases ◽  
Carotid Chemoreceptors ◽  
Arterial Blood ◽  
Carotid Bodies

Discharges from aortic and carotid body chemoreceptor afferents were simultaneously recorded in 18 anesthetized cats to test the hypothesis that aortic chemoreceptors, because of their proximity to the heart, respond to changes in arterial blood gases before carotid chemoreceptors. We found that carotid chemoreceptor responses to the onset of hypoxia and hypercapnia, and to the intravenously administered excitatory drugs (cyanide, nicotine, and doxapram), preceded those of aortic chemoreceptors. Postulating that this unexpected result was due to differences in microcirculation and mass transport, we also investigated their relative speed of responses to changes in arterial blood pressure. The aortic chemoreceptors responded to decreases in arterial blood pressure before the carotid chemoreceptors, supporting the idea that the aortic body has microcirculatory impediments not generally present in the carotid body. These findings strengthened the concept that carotid bodies are more suited for monitoring blood gas changes due to respiration, whereas aortic bodies are for monitoring circulation.

scholarly journals The Effect of Halothane-Nitrous Oxide Anaesthesia and Spontaneous Ventilation on Arterial Blood Oxygenation and Physiological Deadspace

1976 ◽  
Vol 4 (1) ◽  
pp. 41-45
Author(s):  
M. Morgan ◽  
J. Norman
Keyword(s):  
Nitrous Oxide ◽  
Oxygen Tension ◽  
Arterial Oxygen Tension ◽  
Volume Ratio ◽  
Carbon Dioxide Tension ◽  
Blood Oxygenation ◽  
Arterial Oxygen ◽  
Significant Deterioration ◽  
Arterial Blood ◽  
Oxide Anaesthesia

Arterial blood, inspired and expired gas samples were taken from seven patients anaesthetized with halothane (1–2 per cent) and nitrous oxide in oxygen and who breathed spontaneously. Over a two hour period, the average arterial oxygen tension was 75 mm Hg and carbon dioxide tension 49 mm Hg. No significant deterioration of either blood gas value occurred during the two hours. The dead-space/tidal volume ratio and alveolar-arterial oxygen tension difference did not alter significantly during the period of the study.

OXYGEN THERAPY IN THE NEWBORN INFANT

PEDIATRICS ◽  
1971 ◽  
Vol 47 (6) ◽  
pp. 1086-1087
Author(s):  
Jerold F. Lucey ◽  
Marvin Cornblath ◽  
Stanley N. Graven ◽  
Sheldon B. Korones ◽  
L. Stanley James ◽  
...  
Keyword(s):  
Oxygen Concentration ◽  
Oxygen Tension ◽  
Newborn Infant ◽  
Newborn Infants ◽  
Arterial Oxygen Tension ◽  
Arterial Oxygen ◽  
Retrolental Fibroplasia ◽  
Arterial Blood ◽  
Increased Risk ◽  
Inspired Oxygen

The following recommendations will appear in the revision of the manual, Standards and Recommendations for Hospital Care of Newborn Infants, scheduled for publication early in 1971. Because the Committee felt a sense of urgency to provide these recommendations to pediatricians, family physicians, and other health professionals caring for newborn infants, they are being published prior to appearance of the manual. The statement has had extensive review by a large number of experts not on the Committee, and their comments and suggestions have been followed in the preparation of the final draft. It was also reviewed and approved by the Committee on Drugs of the Academy at their meeting in San Francisco October 24, 1970. When a newborn infant needs extra oxygen, it must be administered with great care because there is a causal relationship between a higher than normal oxygen tension in arterial blood (60 to 100 mm Hg) and retrolental fibroplasia (retinopathy of prematurity). When the normal O2 tension is exceeded, there is an increased risk of retrolental fibroplasia. The upper limit of arterial oxygen tension and its duration which are safe for these infants is not known. It is probable that even concentrations of 40% of inspired oxygen (formerly considered safe) could be dangerous for some infants. An inspired oxygen concentration of 40% may be insufficient for infants with cardiorespiratory disease to raise the oxygen tension of arterial blood to a normal level. In such instances, an inspired oxygen concentration of 60%, 80%, or higher may be necessary.

Treatment of Severe Spell Syndrome in Congenitial Heart Disease

PEDIATRICS ◽  
1963 ◽  
Vol 32 (1) ◽  
pp. 141-143
Author(s):  
ABRAHAM M. RUDOLPH ◽  
DELORES DANILOWICZ
Keyword(s):  
Oxygen Tension ◽  
Pulmonary Atresia ◽  
Sodium Bicarbonate Solution ◽  
Arterial Oxygen Tension ◽  
Carbon Dioxide Tension ◽  
Arterial Oxygen ◽  
Unknown Etiology ◽  
Dramatic Improvement ◽  
Low Oxygen ◽  
Arterial Blood

An infant with pulmonary atresia with a ventricular septal defect, developed a severe prolonged spell associated with a possible gastrointestinal hemorrhage of unknown etiology. Arterial blood studies revealed an extremely low oxygen tension, a markedly reduced pH and slightly reduced carbon dioxide tension. Intravenous infusion of sodium bicarbonate solution was associated with dramatic improvement of the child's condition, and a return of arterial blood pH to normal levels although arterial oxygen tension had improved only slightly.

Intraabdominal Surgery and Anesthesia Management

2017 ◽  
Vol 126 (3) ◽  
pp. 543-546
Author(s):  
John Hedley-Whyte
Keyword(s):  
Oxygen Tension ◽  
Arterial Oxygen Tension ◽  
Radical Mastectomy ◽  
Surgical Patients ◽  
Arterial Oxygen ◽  
Pulmonary Atelectasis ◽  
Anesthesia Management ◽  
Controlled Ventilation ◽  
Arterial Blood ◽  
Pulmonary Compliance

Abstract Inspired Oxygenation in Surgical Patients During General Anesthesia With Controlled Ventilation: A Concept of Atelectasis. By Bendixen HH, Hedley-Whyte J, and Laver MB. New Engl J Med 1963; 269:991–996. Reprinted with permission. Abstract The purpose of this study was to determine if the pattern of ventilation, by itself, influences oxygenation during anesthesia and surgery and examine the hypothesis that progressive pulmonary atelectasis may occur during constant ventilation whenever periodic hyperventilation is lacking, but is reversible by passive hyperinflation of the lungs. Eighteen surgical patients, ranging in age from 24 to 87 yr, without known pulmonary disease, were studied during intraabdominal procedures and one radical mastectomy. Although ventilation remained constant, changes occurred in arterial oxygen tension and in total pulmonary compliance, with an average fall of 22% in oxygen tension and 15% in total pulmonary compliance. This fall in oxygen tension supports the hypothesis that progressive mechanical atelectasis may lead to increased venous admixture to arterial blood. The influence of the ventilator pattern on atelectasis and shunting is further illustrated by the reversibility of the fall in oxygen tension that follows hyperinflation. A relation between the degree of ventilation and the magnitude of fall in arterial oxygen tension was found, where large tidal volumes appear to protect against falls in oxygen tension, while shallow tidal volumes lead to atelectasis and increased shunting with impaired oxygenation.

Mechanisms of coronary vasoconstriction induced by high arterial oxygen tension

1997 ◽  
Vol 272 (1) ◽  
pp. H67-H75 ◽  
Author(s):  
S. Mouren ◽  
R. Souktani ◽  
M. Beaussier ◽  
L. Abdenour ◽  
M. Arthaud ◽  
...  
Keyword(s):  
Red Blood Cells ◽  
Oxygen Tension ◽  
Blood Cells ◽  
Arterial Oxygen Tension ◽  
Hemoglobin Concentration ◽  
Nordihydroguaiaretic Acid ◽  
Arterial Oxygen ◽  
Coronary Vasoconstriction ◽  
Arterial Oxygen Content ◽  
Arterial Blood

In isolated rabbit hearts perfused with suspension of red blood cells, we investigated the role of the endothelium and of several substances in the coronary vasoconstriction induced by a high arterial blood oxygen tension (PaO2). Red blood cells in Krebs-Henseleit buffer were oxygenated to obtain control and high-PaO2 perfusates. Arterial oxygen content was kept constant in both perfusates by reducing hemoglobin concentration in the high-PaO2 perfusate. Coronary blood flow was kept constant so that oxygen supply would not vary with the rise in PaO2. Increases in perfusion pressure therefore reflected increased coronary resistance. The high PaO2-induced coronary vasoconstriction was not affected by administration of indomethacin, nordihydroguaiaretic acid, NG-nitro-L-arginine, or superoxide dismutase and catalase but was abolished after endothelium damage or by cromakalim. These results demonstrate that 1) the endothelium contributes to the high PaO2-induced coronary vasoconstriction; 2) this effect is independent of cyclooxygenase or lipoxygenase products, nitric oxide, or free radicals; and 3) the closure of ATP-sensitive K+ channels mediates this vasoconstriction.

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