Hemodynamic responses to oxygen breathing in man

1962 ◽  
Vol 17 (1) ◽  
pp. 75-79 ◽  
Author(s):  
G. W. N. Eggers ◽  
H. W. Paley ◽  
J. J. Leonard ◽  
J. V. Warren

Hemodynamic responses to breathing 100% oxygen for an average of 30 min were studied in eight healthy male volunteers. Cardiac output and related determinations were performed with central injections of a radioactive indicator and calculated by the method of Stewart and Hamilton. Arterial blood gas analyses were performed in each phase of the study. Slight but statistically significant decreases in cardiac index and heart rate were observed during oxygen breathing. There was no change in the central blood volume, but a masked increase in pulmonary blood volume may have occurred. Statistically significant increases in peripheral vascular resistance, mean arterial pressure, and both systolic and diastolic arterial pressures occurred during oxygen breathing and persisted at least 40 min after oxygen was discontinued. Submitted on May 1, 1961

1965 ◽  
Vol 20 (2) ◽  
pp. 215-220 ◽  
Author(s):  
John H. Holt ◽  
Ben V. Branscomb

Cardiopulmonary hemodynamic responses to breathing 100% oxygen for 20 min were studied in 13 patients with moderate to severe chronic obstructive emphysema under conditions of controlled ventilation. A technique for regulating the level of ventilation in the unanesthetized subject is described. Cardiac output was measured by the indicator-dilution method. Arterial blood gas analysis and pH were performed in each phase of the study. A slight but statistically significant decrease in cardiac index occurred. There was a highly significant reduction in pulmonary arterial pressure and pulmonary vascular resistance. No change in heart rate, pulmonary wedge pressure, or aortic pressure occurred. It is concluded that oxygen breathing caused a release, in part at least, of a pulmonary vasoconstrictive element in these patients. pulmonary circulation; oxygen in pulmonary hypertension; hypoxia and pulmonary vasoconstriction; controlled ventilation during oxygen inhalation Submitted on May 27, 1964


Biosensors ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 34 ◽  
Author(s):  
Brian Bradke ◽  
Bradford Everman

Photoplethysmography (PPG) is a valuable technique for noninvasively evaluating physiological parameters. However, traditional PPG devices have significant limitations in high-motion and low-perfusion environments. To overcome these limitations, we investigated the accuracy of a clinically novel PPG site using SPYDR®, a new PPG sensor suite, against arterial blood gas (ABG) measurements as well as other commercial PPG sensors at the finger and forehead in hypoxic environments. SPYDR utilizes a reflectance PPG sensor applied behind the ear, between the pinna and the hairline, on the mastoid process, above the sternocleidomastoid muscle, near the posterior auricular artery in a self-contained ear cup system. ABG revealed accuracy of SPYDR with a root mean square error of 2.61% at a 70–100% range, meeting FDA requirements for PPG sensor accuracy. Subjects were also instrumented with SPYDR, as well as finger and forehead PPG sensors, and pulse rate (PR) and oxygen saturation (SpO2) were measured and compared at various reduced oxygen profiles with a reduced oxygen breathing device (ROBD). SPYDR was shown to be as accurate as other sensors in reduced oxygen environments with a Pearson’s correlation >93% for PR and SpO2. In addition, SPYDR responded to changes in SpO2 up to 50 s faster than PPG measurements at the finger and forehead.


2002 ◽  
Vol 96 (4) ◽  
pp. 860-870 ◽  
Author(s):  
Martin J. London ◽  
Thomas E. Moritz ◽  
William G. Henderson ◽  
Gulshan K. Sethi ◽  
Maureen M. O'Brien ◽  
...  

Background Controversy exists regarding the utility of continuous monitoring of mixed venous oxygen saturation (STvo2) during cardiac surgery. During a multicenter, prospective, observational study in the Department of Veterans Affairs (Cooperative Study #5), frequency of use of standard pulmonary artery catheterization (PAC) and STvo2-PAC was recorded. Here the authors relate these data to clinical outcomes. Methods Logistic and Cox regression models evaluating the association of PAC type with mortality, one or more postoperative complications, cardiac complications, time to extubation, and intensive care unit length of stay were constructed. The number of thermodilution cardiac outputs and arterial blood gas analyses performed in the first 24 h postoperatively were compared. Results Data from 3,265 patients undergoing myocardial revascularization (81.7%) or valve replacement-repair (18.3%) were considered. STvo2-PAC was used in 49% and PAC in 51% of patients. In the 14 hospitals, STvo2-PAC was used in all patients in four, in some patients in four, and never in six. No association of STvo2-PAC use with outcome were observed aside from unexplained hospital level effects. A small but statistically significant reduction in the number of arterial blood gas analyses (8 +/- 3 vs. 10 +/- 4, P < 0.0001, STvo2-PAC vs. PAC, respectively) and thermodilution cardiac outputs (14 +/- 8 vs. 15 +/- 9, P < 0.0001, STvo2-PAC vs. PAC, respectively) was observed with use of STvo2-PAC. Conclusions Despite higher cost, STvo2-PAC was commonly used in this cohort. Our analysis failed to detect associations with improved outcomes aside from a small reduction in resource utilization. The precise role of STvo2-PAC remains uncertain.


2009 ◽  
Vol 19 (3) ◽  
pp. 267-271 ◽  
Author(s):  
Christina Eagan ◽  
Cesar A. Keller ◽  
Maher A. Baz ◽  
Michael Thibault

Objective To observe the effect of naloxone on the lung function of potential lung transplant donors with neurogenic pulmonary edema. Design and Interventions Donors aged 16 to 55 years without any factors to contraindicate lung donation (pneumonia, pulmonary contusion, etc) were included. Ventilator settings were standardized to a tidal volume of 10 to 12 mL/kg, an FiO2 of 0.40, and a respiratory rate that kept PCO2 between 35 and 45 mm Hg. Chest physiotherapy, nebulizer treatments, and frequent suctioning were undertaken. Baseline arterial blood gas analysis and an oxygen challenge were performed. The patients were then given 8 to 10 mg of naloxone. Oxygen challenges and arterial blood gas analyses were repeated every 4 to 6 hours. The data were analyzed by using a paired t test, and each patient served as his or her own control. Setting These interventions were performed on the 19 LifeQuest donors who met the set criteria from July 2002 to July 2004. Results The PaO2 on the oxygen challenge immediately after administration of naloxone increased from 329 (SD 177) to 363 (SD 191) mm Hg, although the increase from baseline was not significant. The PaO2 from the second oxygen challenge (median time, 7 hours after administration of naloxone) increased to 413 (SD 177) mm Hg ( P < .01).


2009 ◽  
Vol 10 (4) ◽  
pp. 279-281 ◽  
Author(s):  
Tim Astles

Anaemia in the critically ill remains a contentious issue. Despite adoption of lower haemoglobin levels as transfusion triggers, many patients on intensive care units (ICUs) still require blood transfusions during their illness. One factor that contributes to the critically ill becoming anaemic is regular phlebotomy. Over a two week period, all blood tests performed on patients in a busy, teaching hospital ICU were surveyed to allow calculation of the total volume of blood that had been taken. On average, 52.4 mL of blood was taken per patient per day, and 366.8 mL per patient per week. The most frequently performed tests were arterial blood gas analyses, performed on average 5.8 times per patient per day (range 0–21 times per day). Arterial blood gas analysis alone accounted for taking of 29 mL of blood per patient per day, ie 203 mL per patient per week. Several methods for reducing the amount of blood taken from ICU patients have been identified and discussed. By implementing some of these simple changes in our institution, it would be possible to reduce the volume of blood taken by 43%.


Respirology ◽  
2014 ◽  
Vol 19 (5) ◽  
pp. 769-769
Author(s):  
Jun Fujinaga ◽  
Akira Kuriyama ◽  
Toshio Fukuoka

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