Arterial Blood Oxygenation During Thoracotomy Using 70 Per Cent Nitrous Oxide in Oxygen

1967 ◽  
Vol 28 (4) ◽  
pp. 705-710 ◽  
Author(s):  
Azmy R. Boutros ◽  
Mary R. Weisel
Keyword(s):  
Nitrous Oxide ◽  
Blood Oxygenation ◽  
Cent Nitrous Oxide ◽  
Arterial Blood

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.

scholarly journals Is the resting rate of oxygen consumption of locomotor muscles in crustaceans limited by the low blood oxygenation strategy?

2001 ◽  
Vol 204 (5) ◽  
pp. 933-940 ◽  
Author(s):  
J. Forgue ◽  
A. Legeay ◽  
J.C. Massabuau
Keyword(s):  
Blood Oxygenation ◽  
Whole Body ◽  
Blood Gas ◽  
Astacus Leptodactylus ◽  
Night Time ◽  
Arterial Blood ◽  
Rate Of Oxygen Consumption ◽  
Locomotor Muscles

Numerous water-breathers exhibit a gas-exchange regulation strategy that maintains O(2) partial pressure, P(O2), in the arterial blood within the range 1–3 kPa at rest during the daytime. In a night-active crustacean, we examined whether this could limit the rate of O(2)consumption (M(O2)) of locomotor muscles and/or the whole body as part of a coordinated response to energy conservation. In the crayfish Astacus leptodactylus, we compared the in vitro relationship between the M(O2) of locomotor muscles as a function of the extracellular P(O2) and P(CO2) and in vivo circadian changes in blood gas tensions at various values of water P(O2). In vitro, the M(O2) of locomotor muscle, either at rest or when stimulated with CCCP, was O(2)-dependent up to an extracellular P(O2) of 8–10 kPa. In vivo, the existence of a night-time increase in arterial P(O2) of up to 4 kPa at water P(O2) values of 20 and 40 kPa was demonstrated, but an experimental increase in arterial P(O2) during the day did not lead to any rise in whole-body M(O2). This suggested that the low blood P(O2) in normoxia has no global limiting effect on daytime whole-body M(O2). The participation of blood O(2) status in shaping the circadian behaviour of crayfish is discussed.

Catecholamines inhibit growth in fetal sheep in the absence of hypoxemia

1998 ◽  
Vol 274 (6) ◽  
pp. R1536-R1545 ◽  
Author(s):  
John M. Bassett ◽  
Clifford Hanson
Keyword(s):  
Growth Hormone ◽  
Weight Gain ◽  
Plasma Glucose ◽  
Fetal Development ◽  
Plasma Insulin ◽  
Blood Oxygenation ◽  
Fetal Sheep ◽  
Inhibition Of Growth ◽  
Arterial Blood ◽  
Chronic Hypoxemia

To evaluate contributions of catecholamines to inhibition of growth during chronic hypoxemia or severe undernutrition, epinephrine (Epi; 0.25–0.35 μg ⋅ kg−1 ⋅ min−1) or norepinephrine (NE; 0.5–0.7 μg ⋅ kg−1 ⋅ min−1) was administered to normoxemic fetuses in twin-pregnant ewes for 8–12 days, from 125 to 127 days of gestation. Both had similar effects and decreased fetal weight by ∼20% relative to control twins ( P < 0.01). Weight gain ceased during infusion of Epi or NE (−21 ± 14.8 or 14 ± 20.9 g/day), whereas controls gained 93 ± 13.2 g/day ( P < 0.01). Effects on tissues and organs varied, spleen and thymus being most retarded, whereas brain weight and skeletal measures were affected little. Selected muscles from infused fetuses weighed 72% of those in controls. Growth ceased during infusion ( P < 0.001). Weight gain of hindlimb bones was negligible, but length increased at 56% of control rates. Arterial blood CO2and plasma insulin were decreased ( P< 0.001), but plasma glucose, growth hormone, and blood oxygenation increased ( P < 0.001). Actions of Epi and NE could underlie asymmetrical growth retardation occurring in many adverse physiological situations during fetal development.

An Integrated I2C Sensor Network for Transcatheter Heart Valves

2020 ◽  
Author(s):  
Thomas W. Secord ◽  
Lucas J. Koerner ◽  
Robert J. Kopas
Keyword(s):  
Pulse Wave Velocity ◽  
Sensor Network ◽  
Wave Velocity ◽  
Pulse Wave ◽  
Severe Aortic Stenosis ◽  
Blood Oxygenation ◽  
Circuit Board ◽  
Measurement Unit ◽  
Propagation Time ◽  
Arterial Blood

Abstract Transcathether aortic heart valve replacement (TAVR) is a widespread approach to treating patients with severe aortic stenosis. A TAVR implant is ideally positioned to access numerous clinically relevant signals including arterial blood pressure, pulse wave velocity, electrocardiogram (ECG), patient motion, heart rate, respiration, and blood oxygenation. Unlike medical devices such as pacemakers, TAVR implants are purely mechanical structures with no sensing capabilities. In this work, we address this unmet clinical need by incorporating an Inter-Integrated Circuit (I2C) sensor network within a TAVR stent frame and designing sensor modules that can physically connect to the network at various landing zones. To illustrate this approach, we designed and built a sensor circuit board populated with a commercial inertial measurement unit (IMU) that can detect clinically useful metrics including pulse wave velocity at the aortic root. We use two spatially separated accelerometers to measure pulse wave propagation time with a standard deviation of 140 μs, which translates to an uncertainty of the pulse wave velocity of ±0.2 m/s. The sensor modules connect to a customized stent frame containing the necessary I2C conductors. Our data suggest that a fully instrumented TAVR paradigm is feasible using this frame design and modular sensor approach.

scholarly journals The Various Oximetric Techniques Used for the Evaluation of Blood Oxygenation

Sensors ◽  
2020 ◽  
Vol 20 (17) ◽  
pp. 4844
Author(s):  
Meir Nitzan ◽  
Itamar Nitzan ◽  
Yoel Arieli
Keyword(s):  
Oxygen Saturation ◽  
Pulse Oximetry ◽  
Near Infrared ◽  
Light Transmission ◽  
Venous Blood ◽  
Blood Oxygenation ◽  
Infrared Light ◽  
Cerebral Tissue ◽  
Peripheral Muscle ◽  
Arterial Blood

Adequate oxygen delivery to a tissue depends on sufficient oxygen content in arterial blood and blood flow to the tissue. Oximetry is a technique for the assessment of blood oxygenation by measurements of light transmission through the blood, which is based on the different absorption spectra of oxygenated and deoxygenated hemoglobin. Oxygen saturation in arterial blood provides information on the adequacy of respiration and is routinely measured in clinical settings, utilizing pulse oximetry. Oxygen saturation, in venous blood (SvO2) and in the entire blood in a tissue (StO2), is related to the blood supply to the tissue, and several oximetric techniques have been developed for their assessment. SvO2 can be measured non-invasively in the fingers, making use of modified pulse oximetry, and in the retina, using the modified Beer–Lambert Law. StO2 is measured in peripheral muscle and cerebral tissue by means of various modes of near infrared spectroscopy (NIRS), utilizing the relative transparency of infrared light in muscle and cerebral tissue. The primary problem of oximetry is the discrimination between absorption by hemoglobin and scattering by tissue elements in the attenuation measurement, and the various techniques developed for isolating the absorption effect are presented in the current review, with their limitations.

Fentanyl Augments the Blockade of the Sympathetic Response to Incision (MAC-BAR) Produced by Desflurane and Isoflurane 

1998 ◽  
Vol 88 (1) ◽  
pp. 43-49 ◽  
Author(s):  
Malcolm Daniel ◽  
Richard B. Weiskopf ◽  
Mariam Noorani ◽  
Edmond I. Eger
Keyword(s):  
Nitrous Oxide ◽  
Cardiovascular Response ◽  
Dependent Manner ◽  
Surgical Incision ◽  
Arterial Blood ◽  
Adrenergic Response ◽  
The Mean ◽  
End Tidal ◽  
Inhaled Anesthetic ◽  
Dose Dependent

Background Heart rate (HR) or mean arterial blood pressure (MAP) may increase in response to incision despite the absence of a motor response. The authors hypothesized that the MAC-BAR (minimum alveolar concentration of an anesthetic that blocks adrenergic response to incision) for isoflurane would exceed that for desflurane, and that fentanyl would decrease the MAC-BAR for each anesthetic in a dose-dependent manner. Methods Seventy-one patients were randomly allocated to one of six groups: desflurane or isoflurane without fentanyl or with 1.5 or 3 microg/kg fentanyl given intravenously 5 min before surgical incision. Anesthesia was induced with 2 mg/kg propofol given intravenously, and tracheal intubation facilitated with 0.1 mg/kg given intravenously. The first patient in each group received 1 MAC (end-tidal) of the inhaled anesthetic in 60% nitrous oxide (0.55 MAC), balance oxygen, maintained for at least 10 min before incision. The response was considered positive if the HR or MAP increased 15% or more. If the response was positive, the end-tidal concentration given to the next patient was 0.3 MAC greater; if the response was negative, the end-tidal concentration was 0.3 MAC less. The MAC-BAR level was calculated as the mean of four independent cross-over responses in each group. Results Desflurane and isoflurane anesthesia with 60% nitrous oxide did not change HR (P &gt; 0.05) and decreased MAP (P &lt; 0.05) before incision. Plasma epinephrine and norepinephrine concentrations after anesthesia and before incision were normal in all groups. The MAC-BAR level, without fentanyl, did not differ (P &gt; 0.05) between desflurane (1.30 +/- 0.34 MAC [mean +/- SD]) and isoflurane (1.30 +/- 0.18 MAC). Fentanyl given at 1.5 microg/kg intravenously equivalently (P &gt; 0.05) reduced the MAC-BAR for desflurane (to 0.40 +/- 0.18 MAC; P &lt; 0.05) and isoflurane (to 0.55 +/- 0.00 MAC; P &lt; 0.05), but a further increase in fentanyl to 3 microg/kg caused no greater decrease in the MAC-BAR for desflurane (0.48 +/- 0.16 MAC) and isoflurane (0.40 +/- 0.30 MAC). Conclusions Clinically attainable doses of desflurane and isoflurane, in 60% nitrous oxide (0.55 MAC), block the cardiovascular response to surgical incision at 1.3 MAC. Fentanyl given at 1.5 microg/kg decreases the MAC-BAR for each agent with no further decrease produced by 3 microg/kg fentanyl.

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