Effect of hyperoxia and hypoxia on exercise-induced breathlessness in normal subjects

1988 ◽  
Vol 74 (5) ◽  
pp. 531-537 ◽  
Author(s):  
N. Chronos ◽  
L. Adams ◽  
A. Guz
Keyword(s):  
Oxygen Saturation ◽  
Oxygen Concentration ◽  
Time Course ◽  
Minute Ventilation ◽  
Arterial Oxygen Saturation ◽  
Normal Subjects ◽  
Secondary Response ◽  
Arterial Oxygen ◽  
Air Breathing ◽  
Inspired Oxygen

1. The subjective changes accompanying alterations in inspired oxygen concentration during heavy exercise have been investigated single blind, in normal subjects. 2. In particular, the intensity of the sensation of breathlessness was quantified using a visual analogue scale and changes were compared with those in objective ventilatory measures. 3. Eleven subjects performed three steady-state workload exercise tests on different days and 100% O2, 15% O2 or air were randomly administered for a fixed interval during each test. 4. Compared with air breathing, all subjects felt less breathless during 100% O2 breathing, and ten of them felt more breathless when inspiring 15% O2; these changes were reversed on return to air breathing. 5. During and after 100% O2, the time course of changes in breathlessness was similar to those for ear arterial oxygen saturation and minute ventilation such that it could be a secondary response to either. However, during and after inspiration of 15% O2, changes in breathlessness occurred relatively more quickly than those in ventilation, more closely reflecting changes in oxygen saturation; this suggests that hypoxia, per se, could contribute to the genesis of this sensation. 6. Individual variability in breathlessness responses to exercise and changes in inspired oxygen concentration did not correlate with objective ventilatory changes; neither were changes in breathlessness in the group particularly associated with changes in respiratory frequency or tidal volume.

Effect of Almitrine on Hypoxic Ventilatory Drive Measured by Transient and Progressive Isocapnic Hypoxia in Normal Men

1989 ◽  
Vol 77 (4) ◽  
pp. 431-437 ◽  
Author(s):  
M. A. A. Airlie ◽  
D. C. Flenley ◽  
P. M. Warren
Keyword(s):  
Oxygen Saturation ◽  
Ventilatory Response ◽  
Minute Ventilation ◽  
Arterial Oxygen Saturation ◽  
Arterial Oxygen ◽  
Controlled Study ◽  
Peripheral Chemoreceptor ◽  
Ventilatory Drive ◽  
The Difference ◽  
Normal Men

1. In a double-blind placebo-controlled study, we have investigated the effect of the peripheral chemoreceptor stimulant drug almitrine bismesylate on hypoxic ventilatory drive (expressed as the slope of the minute ventilation/arterial oxygen saturation relationship in litres min−1 %−1) as measured by both progressive isocapnic hypoxia at rest and transient hypoxia (three breaths of 100% N2) during moderate exercise, in seven normal men, to determine if the ventilatory response to the transient hypoxic stimulus is a more specific measure of peripheral chemoreceptor sensitivity to hypoxia. 2. Hypoxic ventilatory drive measured using progressive isocapnic hypoxia ranged from −0.13 to −2.65 litres min−1 % −1 after placebo and from − 0.20 to − 6.48 litres min−1 %−1 after almitrine. The response was greater after almitrine in six of the seven subjects, and the difference was significant for the whole group (P < 0.05). 3. Hypoxic ventilatory drive measured using transient hypoxia ranged from −0.19 to −1.59 litres min−1 %−1 after placebo and from −0.09 to −1.62 litres min−1 %−1 after almitrine. The response was not consistently greater after almitrine, and the difference was not significant for the group. 4. Difficulties in accurately quantifying a brief rise in minute ventilation after transient hypoxia, particularly in subjects with a low hypoxic ventilatory drive, may have masked small changes in the slope of the minute ventilation/arterial oxygen saturation relationship with this method. However, the significant increase in the response to progressive isocapnic hypoxia after almitrine suggests that the failure to demonstrate an effect using transient hypoxic stimuli was not solely due to between-day variation in hypoxic ventilatory drive or the small numbers of subjects studied. 5. We conclude that, although transient hypoxia avoids any central depression of ventilation that might result from the prolonged hypoxia used in the conventional steady state or progressive isocapnic methods (thereby leading to underestimation of the hypoxic ventilatory drive), the ventilatory response to such transient stimuli is also affected by factors other than peripheral chemoreceptor activity.

Engineering Evaluation of the Performance of an Automatic Peripheral Oxygen Controller Using a Neonatal Respiratory Model

2018 ◽  
Vol 12 (3) ◽  
Author(s):  
Akram Faqeeh ◽  
Roger Fales ◽  
John Pardalos ◽  
Ramak Amjad ◽  
Isabella Zaniletti ◽  
...  
Keyword(s):  
Oxygen Saturation ◽  
Arterial Oxygen Saturation ◽  
Respiratory Support ◽  
Arterial Oxygen ◽  
Target Range ◽  
Care Providers ◽  
Manual Adjustment ◽  
Fraction Of Inspired Oxygen ◽  
Dynamic Adaptability ◽  
Inspired Oxygen

Premature infants often require respiratory support with a varying concentration of the fraction of inspired oxygen FiO2 to keep the arterial oxygen saturation typically measured using a peripheral sensor (SpO2) within the desired range to avoid both hypoxia and hyperoxia. The widespread practice for controlling the fraction of inspired oxygen is by manual adjustment. Automatic control of the oxygen to assist care providers is desired. A novel closed-loop respiratory support device with dynamic adaptability is evaluated nonclinically by using a neonatal respiratory response model. The device demonstrated the ability to improve oxygen saturation control over manual control by increasing the proportion of time where SpO2 is within the desired range while minimizing the episodes and periods where SpO2 of the neonatal respiratory model is out of the target range.

Nocturnal desaturation and serum erythropoietin: A study in patients with chronic obstructive pulmonary disease and in normal subjects

1993 ◽  
Vol 84 (3) ◽  
pp. 319-324 ◽  
Author(s):  
Michael F. Fitzpatrick ◽  
Tom MacKay ◽  
Kenneth F. Whyte ◽  
Martin Allen ◽  
Robert C. Tam ◽  
...  
Keyword(s):  
Chronic Obstructive Pulmonary Disease ◽  
Oxygen Saturation ◽  
Pulmonary Disease ◽  
Arterial Oxygen Saturation ◽  
Normal Subjects ◽  
Arterial Oxygen ◽  
Chronic Obstructive ◽  
Obstructive Pulmonary Disease ◽  
Serum Erythropoietin Level ◽  
Serum Erythropoietin

1. To clarify the relationship between nocturnal oxygen desaturation and erythropoietin production in patients with chronic obstructive pulmonary disease, we determined arterial oxygen saturation and serum immunoreactive erythropoietin levels over 24 h in eight patients with chronic obstructive pulmonary disease and in nine normal subjects. 2. In the normal subjects, there was a significant circadian variation in serum erythropoietin levels with the highest mean deviation from the geometric mean at 22.00 hours and the nadir at 05.00 hours. 3. The three patients with chronic obstructive pulmonary disease with the most marked nocturnal desaturation (lowest arterial oxygen saturation <57%) and most marked daytime hypoxaemia (daytime arterial partial pressure of oxygen < 6 kPa) had raised nocturnal serum erythropoietin levels. In two of these patients, the serum erythropoietin level was raised throughout the 24 h and erythrocyte mass was also raised. In the other patient, the serum erythropoietin level was not raised in five daytime samples and erythrocyte mass was normal. 4. The other five patients with chronic obstructive pulmonary disease with less severe nocturnal hypoxaemia (lowest arterial oxygen saturation range 78–86%) had serum erythropoietin levels (range 14–36 m-i.u./ml) which were indistinguishable from normal (range 12–44 m-i.u./ml) and showed circadian changes which were not significantly different (P = 0.35) from those in the normal subjects. 5. Thus, mild nocturnal oxygen desaturation is not associated with elevation of serum erythropoietin levels, whereas daytime hypoxaemia with associated severe nocturnal desaturation is associated with increased serum erythropoietin levels both by day and by night.

Cardiovascular and ventilatory response to isocapnic hypoxia at sea level and at 5,050 m

1996 ◽  
Vol 80 (5) ◽  
pp. 1724-1730 ◽  
Author(s):  
G. Insalaco ◽  
S. Romano ◽  
A. Salvaggio ◽  
A. Braghiroli ◽  
P. Lanfranchi ◽  
...  
Keyword(s):  
Oxygen Saturation ◽  
Sea Level ◽  
Minute Ventilation ◽  
Arterial Oxygen Saturation ◽  
Arterial Oxygen ◽  
Ventilatory Responses ◽  
Hypoxic Conditions ◽  
Progressive Hypoxia ◽  
End Tidal ◽  
End Tidal Co2

To assess the effect of chronic hypoxic conditions on ventilatory, heart rate (HR), and blood pressure (BP) responses to acute progressive isocapnic hypoxia, we studied five healthy Caucasian subjects (3 men and 2 women). Each subject performed one rebreathing test at sea level (SL) and two tests at the Pyramid laboratory at Lobuche, Nepal, at the altitude of 5,050 m, 1 day after arrival (HA1) and after 24 days of sojourn (HA2). The effects of progressive isocapnic hypoxia were tested by using a standard rebreathing technique. BP, electrocardiogram, arterial oxygen saturation, airflow and end-tidal CO2 and O2 were recorded. For each subject, the relationships between arterial oxygen saturation and HR, systolic BP and minute ventilation (VE), respectively, were evaluated. At HA1, the majority of subjects showed a significant increase in VE and BP response and a decrease in HR response to progressive isocapnic hypoxia as compared to SL. At HA2, VE and BP responses further increased, whereas the HR response remained similar to that observed at HA1. A significant relationship between hypoxic ventilatory responses and both systolic and diastolic BP responses to progressive hypoxia was found. No significant correlation was found between hypoxic ventilatory and HR responses.

Effects of Inspired Hypoxic and Hypercapnic Gas Mixtures on Cerebral Oxygen Saturation in Neonates with Univentricular Heart Defects

2002 ◽  
Vol 96 (2) ◽  
pp. 283-288 ◽  
Author(s):  
Chandra Ramamoorthy ◽  
Sarah Tabbutt ◽  
C. Dean Kurth ◽  
James M. Steven ◽  
Lisa M. Montenegro ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Mean Arterial Pressure ◽  
Oxygen Saturation ◽  
Single Ventricle ◽  
Cerebral Oxygenation ◽  
Arterial Oxygen Saturation ◽  
Cerebral Oxygen Saturation ◽  
Arterial Oxygen ◽  
Cerebral Oxygen ◽  
Inspired Oxygen

Background Neonates with functional single ventricle often require hypoxic or hypercapnic inspired gas mixtures to reduce pulmonary overcirculation and improve systemic perfusion. Although the impact of these treatments on arterial oxygen saturation has been described, the effects on cerebral oxygenation remain uncertain. This study examined the effect of these treatments on cerebral oxygen saturation and systemic hemodynamics. Methods Neonates with single ventricle mechanically ventilated with room air were enrolled in a randomized crossover trial of 17% inspired oxygen or 3% inspired carbon dioxide. Each treatment lasted 10 min, followed by a 10-20-min washout period. Cerebral and arterial oxygen saturation were measured by cerebral and pulse oximetry, respectively. Cerebral oxygen saturation, arterial oxygen saturation, and other physiologic data were continuously recorded. Results Three percent inspired carbon dioxide increased cerebral oxygen saturation (56 +/- 13 to 68 +/- 13%; P &lt; 0.01), whereas 17% inspired oxygen had no effect (53 +/- 13 to 53 +/- 14%; P = 0.8). Three percent inspired carbon dioxide increased the mean arterial pressure (45 +/- 8 to 50 +/- 9 mmHg; P &lt; 0.01), whereas 17% inspired oxygen had no effect. And 3% inspired carbon dioxide decreased arterial pH and increased arterial carbon dioxide and oxygen tensions. Conclusions Inspired 3% carbon dioxide improved cerebral oxygenation and mean arterial pressure. Treatment with 17% inspired oxygen had no effect on either.

scholarly journals Arterial oxygen saturation and hypoxemia in hemodialysis patients with COVID-19

2021 ◽  
Author(s):  
Priscila Preciado ◽  
Leticia M Tapia Silva ◽  
Xiaoling Ye ◽  
Hanjie Zhang ◽  
Yuedong Wang ◽  
...  
Keyword(s):  
Oxygen Saturation ◽  
Time Course ◽  
Clinical Symptoms ◽  
Arterial Oxygen Saturation ◽  
Laboratory Data ◽  
Hemodialysis Patients ◽  
Arterial Oxygen ◽  
Maintenance Hemodialysis ◽  
Treatment Level ◽  
Improvement Project

Abstract Background Maintenance hemodialysis (MHD) patients are particularly vulnerable to COVID-19, a viral disease that may cause interstitial pneumonia, impaired alveolar gas exchange, and hypoxemia. We ascertained the time course of intradialytic arterial oxygen saturation (SaO2) in MHD patients between 4 weeks pre- and the week post-diagnosis of COVID-19. Methods We conducted a quality improvement project in confirmed COVID-19 in-center MHD patients from 11 dialysis facilities. In patients with an arterio-venous access SaO2 was measured 1x/minute during dialysis using the Crit-Line monitor (Fresenius Medical Care, Waltham, MA). We extracted demographic, clinical, treatment, and laboratory data and COVID-19 related symptoms from the patients’ electronic health records. Results Intradialytic SaO2 was available in 52 patients (29 males; age 66.5±15.7 years) contributing 338 hemodialysis treatments. Mean time between onset of symptoms indicative of COVID-19 and diagnosis was 1.1 days (median 0; range 0 to 9). Prior to COVID-19 diagnosis the rate of hemodialysis treatments with hypoxemia, defined as treatment-level average SaO2 &lt; 90%, increased from 2.8% (2 to 4 weeks pre-diagnosis) to 12.2% (1 week) and 20.7% (3 days pre-diagnosis). Intradialytic oxygen supplementation increased sharply post-diagnosis. Eleven patients died from COVID-19 within 5 weeks. Compared to patients who recovered from COVID-19, demised patients showed a more pronounced decline in SaO2 prior to COVID-19 diagnosis. Conclusion In hemodialysis patients, hypoxemia may precede the onset of clinical symptoms and the diagnosis of COVID-19. A steep decline of SaO2 is associated with poor patient outcomes. Measurements of SaO2 may aid the pre-symptomatic identification of patients with COVID-19.

Quantitative analysis of the effect of fraction of inspired oxygen on peripheral oxygen saturation in healthy volunteers

2020 ◽  
Author(s):  
Ji-Yeon Bang ◽  
Changhun Cho ◽  
Eun-Kyung Lee ◽  
Byung-Moon Choi ◽  
Gyu-Jeong Noh
Keyword(s):  
Oxygen Saturation ◽  
Acute Hypoxia ◽  
Arterial Oxygen Saturation ◽  
Arterial Oxygen ◽  
Peripheral Oxygen Saturation ◽  
Turnover Model ◽  
Inhibitory Function ◽  
Short Term Exposure ◽  
Fraction Of Inspired Oxygen ◽  
Inspired Oxygen

Abstract Background The international organization for standardization (ISO) 80601-2-61 dictates that the accuracy of a pulse oximeter should be assessed by a controlled desaturation study. We aimed to characterize the relationship between the fraction of inspired oxygen (FiO 2 ) and peripheral oxygen saturation (SpO 2 ) using a turnover model by retrospectively analyzing the data obtained from previous controlled desaturation studies. We also measured the changes in biomarkers expected to be related to hypoxia (i.e., lactate, carboxyhemoglobin (COHb), and methemoglobin (MetHb)) in response to short-term exposure to hypoxia.Methods Volunteers were exposed to various levels of induced hypoxia over 70−100% arterial oxygen saturation (SaO 2 ). The study period consisted of two rounds of hypoxia and the volunteers were maintained in room air between each round. FiO 2 and SpO 2 were recorded continuously during the study period. A population pharmacodynamic analysis was performed with the NONMEM VII level 4 (ICON Development Solutions, Ellicott City, MD, USA). Lactate, COHb, and MetHb were measured using a CO-oximeter.Results In total, 2899 SpO 2 data points obtained from 20 volunteers were used to determine the pharmacodynamic characteristics. The pharmacodynamic parameters were as follows: k out = 0.942 1/min, Imax = 0.802, IC 50 = 85.3%, γ = 27.3. The changes in SpO 2 due to decreases in FiO 2 well explained by the turnover model with inhibitory function as a sigmoidal model. As SpO 2 decreased, lactate and COHb increased as a whole, and COHb showed the best correlation (Pearson’s correlation, R 2 =0.3263, P < 0.0001).Conclusion The potency of FiO 2 required to reduce SpO 2 from 100% to 70% was 14.7%. Carboxyhemoglobin has the potential to be a useful biomarker for acute hypoxia.

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