An electrode for PN2O and PO2 analysis in blood and gas

Albery, W. John; Brooks, W. N.; Gibson, S. P.; Hahn, C.E.W.

doi:10.1152/jappl.1978.45.4.637

Cited by 32 publications

(13 citation statements)

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“…Blood gas samples were analysed immediately at point of contact in the operating suite on an ABL 625 blood gas analyser (Radiometer, Copenhagen). This analyser uses a platinum PO 2 electrode operating at − 0.63 V which remains accurate in the presence of N 2 O [15]. The electrode was calibrated daily to confirm its stability due to the possibility of silver ion deposition on the platinum cathode, which can cause interference in PO 2 measurement by N 2 O.…”

Section: Methodsmentioning

confidence: 99%

Persisting concentrating and second gas effects on oxygenation during N₂O anaesthesia

et al. 2006

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SummaryTheoretical modelling predicts that the concentrating effect of nitrous oxide (N 2 O) uptake on alveolar oxygenation is a persisting phenomenon at typical levels of ventilation -perfusion (V ⁄ Q) inhomogeneity under anaesthesia. We sought clinical confirmation of this in 20 anaesthetised patients. Arterial oxygen pressure (P a O 2 ) was measured after a minimum of 30 min of relaxant general anaesthesia with an inspired oxygen (F I O 2 ) of 30%. Patients were randomly allocated to two groups. The intervention group had N 2 O introduced following baseline blood gas measurements, and the control group continued breathing an identical F I O 2 in nitrogen (N 2 ). The primary outcome variable was change in P a O 2 . Mean (SD) in P a O 2 was increased by 1.80 (1.80) kPa after receiving a mean of 47.5 min of N 2 O compared with baseline conditions breathing O 2 ⁄ N 2 (p = 0.01). This change was significantly greater (p = 0.03) than that in the control group: + 0.09 (1.37) kPa, p = 0.83 and confirms the presence of significant persisting concentrating and second gas effects. The concentrating and second gas effects of nitrous oxide (N 2 O) uptake on the alveolar partial pressure of oxygen (O 2 ) and volatile agents were described by Eger and Stoelting [1, 2]. They detailed how these effects are produced by the initial rapid uptake of N 2 O for the first several minutes of an inhalational anaesthetic, during which time the rate of N 2 O uptake sharply declines. Subsequent authors have followed the effect on end-tidal and arterial partial pressures with serial measurements, and some authors have questioned the clinical validity of the phenomenon, at least in relation to its effect on volatile agent concentrations [3]. However, Nishikawa et al. found a measurable effect on end-tidal O 2 concentration and arterial oxygen tension (P a O 2 ) up to 30 min after commencement of N 2 O [4]. These largely descriptive studies have been variously uncontrolled for important physiological factors that might potentially influence the effect, such as cardiac output, ventilation-perfusion matching, or time.More recently, computer modelling of alveolar gas exchange predicted that the better arterial oxygenation that results may not be short lived, but may persist indefinitely [5,6]. This prolonged effect is only predicted to be significant in the presence of moderately severe degrees of ventilation-perfusion (V ⁄ Q) inhomogeneity, and is due to ongoing N 2 O uptake in low V ⁄ Q lung units [6]. These levels of V ⁄ Q inhomogeneity are typical of anaesthetised patients, even those with healthy lungs [7][8][9][10][11]. However, N 2 O accelerates absorption atelectasis in regions of low V ⁄ Q [12,13] and may worsen shunting

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Section: Methodsmentioning

confidence: 99%

Persisting concentrating and second gas effects on oxygenation during N₂O anaesthesia

et al. 2006

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“…This is achieved by an appropriate choice of over-potential (k0.6 to k0.7 V for O # and k1.0 to k1.1 V for N # O) to drive the reduction of the dissolved gas [17]. This is achieved by an appropriate choice of over-potential (k0.6 to k0.7 V for O # and k1.0 to k1.1 V for N # O) to drive the reduction of the dissolved gas [17].…”

Section: Tissue P O 2 and Perfusion Measurementsmentioning

confidence: 99%

Myocardial tissue oxygen supply and utilization during coronary artery bypass surgery: evidence of microvascular no-reflow

et al. 2000

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The supply and utilization of oxygen by the myocardium reflect the dynamic efficiency of the microcirculation. The present study examines these parameters during coronary artery bypass surgery. We used a voltammetric microelectrode technique to assess regional variations in myocardial tissue partial pressure of oxygen (PO(2)) and myocardial tissue perfusion (MTP) in patients undergoing coronary artery bypass surgery. A total of 29 myocardial regions were studied in 17 patients to assay tissue PO(2), and 13 regions in 10 patients to measure MTP. There was an increase in MTP from 53+/-9 ml.min(-1).100 g(-1) before cardiopulmonary bypass to 72+/-13 ml. min(-1).100 g(-1) after (means+/-S.E.M.; P=0.05). Tissue PO(2) showed an overall increase from a baseline level of 45+/-8 mmHg to a final level of 88+/-10 mmHg (P<0.0001). Following release of the aortic cross-clamp there was a variable time delay before a change in tissue PO(2) was observed. There was an immediate response in five regions, whereas in 20 regions the response was delayed by between 0.5 and 32 min. In the remaining four regions there was no change in tissue PO(2). The duration of the delay in response was correlated positively with the cross-clamp time (r=0.45, P<0.05) and negatively with the final tissue PO(2) (r=-0.5, P<0.05). Voltammetric methods for monitoring changes in oxygen supply and utilization offer new insights into the changes that occur during ischaemia and reperfusion. A delay in the delivery of oxygen to the myocardium occurs in many patients following coronary artery bypass surgery.

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“…19 Tissue oxygenation and perfusion can be assessed with needle electrodes. Albery et al, 20 in 1978, first described this measurement technique, which enables the simultaneous detection of oxygen and nitrous oxide concentrations in either gas or blood. The method was advanced further in an in vitro study by Hahn et al, 21 who investigated gas concentrations in electrolyte solutions.…”

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confidence: 99%

The effect of hip resurfacing on oxygen concentration in the femoral head

Steffen

Smith

Urban

et al. 2005

The Journal of Bone and Joint Surgery. British volume

100

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We inserted an electrode up the femoral neck into the femoral head of ten patients undergoing a metal-on-metal hip resurfacing arthroplasty through a posterior surgical approach and measured the oxygen concentration during the operation. In every patient the blood flow was compromised during surgery, but the extent varied. In three patients, the oxygen concentration was zero at the end of the procedure. The surgical approach caused a mean 60% drop (p < 0.005) in oxygen concentration while component insertion led to a further 20% drop (p < 0.04). The oxygen concentration did not improve significantly on wound closure. This study demonstrates that during hip resurfacing arthroplasty, patients experience some compromise to their femoral head blood supply and some have complete disruption.

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An electrode for PN2O and PO2 analysis in blood and gas

Cited by 32 publications

References 0 publications

Persisting concentrating and second gas effects on oxygenation during N₂O anaesthesia

Persisting concentrating and second gas effects on oxygenation during N₂O anaesthesia

Myocardial tissue oxygen supply and utilization during coronary artery bypass surgery: evidence of microvascular no-reflow

The effect of hip resurfacing on oxygen concentration in the femoral head

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An electrode for PN2O and PO2 analysis in blood and gas

Cited by 32 publications

References 0 publications

Persisting concentrating and second gas effects on oxygenation during N2O anaesthesia

Persisting concentrating and second gas effects on oxygenation during N2O anaesthesia

Myocardial tissue oxygen supply and utilization during coronary artery bypass surgery: evidence of microvascular no-reflow

The effect of hip resurfacing on oxygen concentration in the femoral head

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Product

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Persisting concentrating and second gas effects on oxygenation during N₂O anaesthesia

Persisting concentrating and second gas effects on oxygenation during N₂O anaesthesia