Heretofore, the technical difficulties encountered in the measurement of blood nitrogen tension (PN2) by gas chromatographic techniques effectively prevented the utilization of PN2 as a clinical tool to characterize mismatching of pulmonary ventilation and perfusion. The development of mass spectrometric techniques allows for the accurate measurement of blood gas tensions; ...

Oxygen tension and potential difference were measured in the gastric mucosa of anesthetized dogs with an ultramicroelectrode technqiue while total blood flow and arteriovenous oxygen content difference were measured. In the control period, measurements were: gastric blood flow, 102.4 +/- 3.0 ml per min per 100 g of tissue; calculated ...

The effect of oxygen tension (Po2) on oxygen consumption (Vo2) of rabbit liver slices was investigated to determine the relationship between extracellular fluid Po2 and liver slice Vo2. Seventy rabbits, 5 kg each, were sacrificed with air embolism. Liver slices (0.3 gm) in Krebs-Ringer's-phosphate (KRP) dextrose were placed in a ...

Measurement of arterial and liver tissue oxygen tension (PO2) in animals subjected to hemorrhagic shock demonstrates a significant (p less than 0.001) decrease in tissue PO2 while PaO2 remains essentially unchanged. In fact, marked increase in PaO2 fail to increase tissue PO2 to control levels, demonstrating that the act of ...

A modification of the technique of photoelectric plethysmography has been developed to monitor changes in the microcirculation of the human periodontal ligament and adjacent alveolar bone, whereby detection is made of light reflected from or transmitted through a tissue during alterations in blood volume, flow or distribution. Light is conducted ...

1. A new open-circuit respiratory method was developed to estimate mixed venous PCO2 more rapidly and accurately than is possible with rebreathing techniques. 2. The subject breathes a mixture of CO2 in air from an open circuit. Carbon dioxide is added to the air flowing through the circuit at a ...

1. The effects of carbon dioxide, oxygen and pH on the inversion intensity of phototaxis of Chlamydomonas reinhardtii have been investigated. 2. With decreasing with CO2 tension the inversion intensity is decreased. 3. The gassing with CO2 can be substituted by hydrogencarbonate only to a small extent (20%). On the ...

A microelectrode with a tip of 100micron permitting recording of the oxygen tension in the perilymphatic space according to the polarographic principle and having a minimal drift of 1-25% per hour has been developed. The effects of apnea, hypo- and hyperventilation as well as those of inhalation of pure oxygen, ...

Monitoring of the state of oxygenation of surgical patients during and after anesthesia has been a problem of increasing interest, especially in those cases in which clinical judgment of skin colour alone is unreliable. Therefore a clinical trial is described with a bed-side PO2-measuring device. Results of duplo measurements in ...

Arterial and venous blood gas tensions and pH were determined in 8 dogs during a control interval, while adrenal deficient, and following replacement therapy with corticosteroids. Additionally, erythrocyte 2,3-diphosphoglycerate (DPG) values were measured, and oxygen tension (mm of Hg) when hemoglobin is half-saturated with oxygen (P50) values were calculated. Mixed ...

An equipment constructed by the International Biophysics Corporation, the Differential Oxygen Analyzer, which was designed for continuous recording of the oxygen tension in the blood, particularly during extracorporeal circulation, was tested. It proved to react rather slowly to changes in the PO2 and the magnitude of the error of the ...

Endolymphatic O2-concentration was measured in the guinea pig cochlea with a microelectrode inserted through the zona pectinata of the basilar membrane and the cells of Claudius, so as not to interfere with the blood supply to the organ of Corti. The O2-level and the amplitude of the cochlear potentials were ...

Using the photometric micromethod of Niesel and Thews the authors determined the oxygen fixation blood curves at 20 degrees C and at CO2 tension of 38 mm Hg in newborn piglests until 71 days post partum. The O2 affinity of the piglet blood which is high immediately after birth, decreases ...

A new electrode for measuring the transcutaneous oxygen tension (tc-PO2) is described. The electrode has been tried out on newborn infants suffering from idiopathic respiratory distress syndrome (IRDS), and the results obtained have been compared with the arterial oxygen tension (PaO2). A fairly close agreement was found, and the least ...

Early effects of 10% full-thickness skin burn on subcutaneous tissue PO2 and PCO2 levels were studied in anesthetized rabbits. Tissue gas tensions were determined by means of implanted Silastic tonometers in two different areas in each animal--the burn site itself, and an area remote from the injured tissue. Thermal injury ...

The changes occurring in renal cortical and medullary tissue oxygen tensions and in renal total blood flow (RBF) were studied during haemorrhagic hypotension in six dogs. The flow was measured with an electromagnetic flowmeter, and tissue oxygen tension with IBC (Ineternational Biophysics Corporation, USA) oxygen electrodes. Haemorrhagic hypotension led to ...

The changes occurring in plasma renin activity (PRA), tissue oxygen tension of the renal cortex and the change in renal total blood flow were studied during haemorrhagic hypotension in six dogs. The flow was measured with an electromagnetic flowmeter, the plasma renin activity was determined by radioimmunoassay and tissue oxygen ...

This study establishes the mean values, variations, and trend of pulmonary function during the first few hours of life in premature lambs. Measurements of intraesophaheal and tracheal pressure, air flow, tidal volume, and functional residual capacity enabled calculations of lung compliance, specific lung compliance, and inspiratory and expiratory resistance of ...

The oxygen tension in the oviductal fluid of adult female rhesus monkeys was measured by means of miniaturized, flexible, oxygen probes between days 5 and 22 of the menstrual cycle. In the follicular phase, the value was very low, less than 10 Torr. At the time of ovulation to about ...

In each of ten healthy young subjects breathing different concentrations of CO2 in O2, four alveolar CO2-tension levels were obtained, ranging from about 20 mmHg when hyperventilating in O2 to 50 mmHg. Maximum expiratory flows at 60% total lung capacity were measured at each level and corrected for the influence ...

Arterial blood gas tensions were measured before and during upper gastrointestinal endoscopy, with (group I) and without (group 2) sedation with intravenous diazepam. There was a highly significant fall in the PaO2, which occurred in both groups and was therefore not attributable to diazepam. Measurement of FEV, and FVC before ...

The phenomenon of "diffusion hypoxemia" seems to be a well-defined entity. To determine the degree of deoxygenation of the arterial blood due to diffusion hypoxemia, experiments were performed in monkeys which were anesthetized with ketamine, intubated, and allowed to breathe spontaneously. Blood PaO2 values were continuously monitored with the aid ...

Cerebral responses to the substitution of 60% nitrous oxide for nitrogen during halothane anaesthesia (0.84%, end-tidal) were studied in four patients during surgery. The mean (+/-SEM) cerebral blood flow equivalent and internal jugular venous oxygen tension during halothane anaesthesia, 17+/-3 ml blood/ml oxygen and 41+/-2 mm Hg respectively, increased significantly ...

Five male alpacas native to high altitude, of approximately 40 kg, were studied first at 3,300 m and again after a 3-month sojourn at sea level. Measurements were made with the animals standing, unsedated and breathing air. Cardiac output was measured by the dye dilution technique. Blood gas tensions and ...

The effects of phenoxybenzamine HCl and propranolol HCl, 2 mg/kg, on tissue oxygen tension (PO2), perfusion and small vessel blood content of the cerebral cortex and biceps brachii muscle of anesthetized rats were determined. Perfusion and PO2 were measured polarographically and small vessel blood content was measured with 59Fe-siderophilin-labeled blood. ...

We found that an abnormal hemoglobin with a very low oxygen affinity was responsible for overt cyanosis in an otherwise healthy adolescent. Hemoglobin Beth Israel, in which serine replaces the asparagine residue normally present at position 102 (G4) of the beta-polypeptide chain, was associated with normal blood counts and no ...

The transcutaneous oxygen tension (tcPo2) in five healthy subjects and in seven patients was monitored continuously by the technique of Huch, Huch, and Lübbers. The inspired oxygen concentration was varied between 15 and 100%. Once stable tcPo2 recordings were obtained, blood samples were drawn via an indwelling arterial catheter for ...

The effects of reduction in perfusion pressure, arterial hypoxia, muscle contraction, and adrenergic stimulation on the hindlimb muscle circulation were studied. Under normal conditions (venous PO2 greater than or equal to 40 mm Hg), oxygen delivery to the muscle was maintained mainly by large increases in the capillary exchange capacity ...

The oxygen tension of the human perilymph has been determined without complications by using a technique based upon the polarographic principle. Carbon dioxide produced the most marked increase in oxygen tension in the human perilymph. No change in the perilymphatic PO2 was observed after administration of eupaverine and low molecular ...

1 The butyrophenone tranquilizer, azaperone, was administered intramuscularly, at dose levels of 0.4 and 0.8 mg/kg, to ponies and its effects on cardiovascular and respiratory functions assessed. 2 Arterial blood pH, CO2 tension (PaCO2) and O2 tension (PaO2) remained relatively constant throughout the course of action of azaperone. 3 Azaperone ...

A prospective, randomized comparison was made of the value of meperidine versus epidural analgesia when used for the relief of pain after cholecystectomy in twenty patients without cardiopulmonary disease. Respiratory function was assessed the day before surgery and at 3 to 4 hours and 24 hours after operation by the ...

Halothane, independent of oxygen tension, increased the signal of the gold/silver-silver chloride microelectrode. The output of microelectrodes at different oxygen tensions in the presence of increasing amounts of halothane has been measured. Halothane causes an increase in the electrode signal which is proportional to its concentration. This effect results from ...

Small catheters (ca. 3 mm diam at tip) were wedged in subsegmental bronchi in anesthetized coatimundi (Nasua nasua) during spontaneous breathing. Mixed expired gases of a group of lobules were sampled continuously without contamination from neighboring units, and local tidal volume, frequency, carbon dioxide production, and oxygen consumption were measured, ...

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 ...

A study was carried out in 100 patients aged between 70 and 90 years to investigate pathological and respiratory function changes in old age. Vitalograph and peak flow meter measurements were made, but blood gas analysis was only carried out in 6 patients in view of the technical difficulties. Analysis ...

The blood oxygen tension (PaO2) was measured using a Clark-type microelectrode on 'arterialised' capillary blood samples obtained from 74 sitting subjects; these were asymptomatic and spirographically normal men aged 42-63 (average 53.7) years. The mean PaO2 of smokers (83.8+/-6.0 mm Hg) was slightly, non-significantly lower as compared to non-smokers (85.5+/-4.9 ...

1. The effects of quinidine on blood flow rate and developed tension were studied in isolated, blood-perfused papillary muscle preparations of the dog. Drugs were injected into the anterior septal artery. 2. Quinidine caused a dose-related increase in blood flow rate; the mean dose producing a 100% increase in blood ...

A polystyrene-covered platinum electrode (100-150 mum diameter) has been used to measure cortical tissue oxygen tension in baboon brains. The method of preparation, calibration, and the importance of small residual current (less than 40 nA) as an attribute of a reliable electrode, are described. With electrodes of this size, there ...

The effect of furosemide (2 mg/kg i.v.) on blood flowin the renal artery and the tissue oxygen tension of the renal cortex and medulla was investigated in six dogs. The flow was measured with an electromagnetic flowmeter and the tissue oxygen tension with IBC tissue oxygen electrodes. The flow in ...

The relationship between respiratory insufficiency, expressed by gas tensions in blood and bone marrow, and haematologic adaptation has been studied in 82 men with chronic bronchitis and persistent breathlessness for at least one year. For the group as a whole and for various subgroups, a linear correlation was demonstrated between ...

Continued experience confirms the suitability of electrovitreotomy for dividing pathogenically taut proliferative and non-proliferative vitreous forms with a minimum of bleeding, and an inability to cut vitreous of ordinary consistency and tension. It differs directly with electrovitrectomy in these regards. To use effectively with a minimum of complications it is ...

The IBC in-vivo oxygen electrode may be used during anesthesia. The possibility that three common inhalation anesthetics--halothane, enflurane, and methoxyflurane--might be reduced at the electrode, thereby changing the PO2 value, was tested. Enflurane and methoxyflurane do not affect the current produced at the electrode; halothane significantly increases PO2 readings at ...

A continuous flow device utilizing a Clark oxygen electrode was constructed; this device had a dead time and resolution of 1 ms. Mixing was tested by observing the neurtralization of acid with base, and at the maximal flow rate, the mixing was 94% complete within 1 ms and better than ...

Effects of acetylcholine (ACh) and norepinephrine on atrial contractility and pacemaker activity were investigated in isolated and blood-perfused canine atrium preparations whith a support dog which were suspended in the blood-filled bath kept at 37 degrees C. The drug was given in two forms of administration, i.e., intraarterial injection into ...

An evaluation of the accuracy, perdision, and clinical safety of the IBC indwellling catheter electrode for the continuous monitoring of arterial oxygen tension during and after general anesthesia was made in a total of 62 patients. A comparison of the standard bench-type electrode (Radiometer) with the International Biophysics Corporation (IBC) ...

Tissue oxygen tensions in healing anastomoses of rabbit abdominal aortas were measured with ultramicro-oxygen cathodes with 1 to 3 mum tips. Two days after constructing the anastomosis, the over-all profile of intramural oxygen tension was different markedly from that of normal aortic wall, showing a progressive fall of Po2 from ...

Oxygen and carbon dioxide tensions of arterial blood and subcutaneous tissue were studied in rats during 84 h of continuous exposure to oxygen. O2 and CO2 tensions in the subcutaneous tissue were measured by means of an implanted Silastic tonometer. As pulmonary edema developed after 48 h of exposure to ...

The measurement of arterial oxygen tension (PaO2) has for some time now been regarded as an essential part of the management of newborn babies receiving oxygen therapy. A system for monitoring arterial oxygen tension by means of a catheter-tip transducer is described. Comparisons of the transducer output with PO2 obtained ...

In order to clarify the effects of flunarizine, a newly-synthesized derivative of piperazine on cerebral circulation and metabolism, cerebrocortical oxygen tension, carbon dioxide tension and cerebrocortical blood flow were continuously recorded, along with a simultaneous monitoring of arterial blood pressure in 11 cats. Maximal changes in cerebrocortical oxygen tension induced ...

Respiratory function and acid-base variables were studied in Welsh Mountain ponies before and at predetermined times after the intravenous injection of Immobilon and Revivon.A marked depression of respiratory rate was accompanied by large reductions in arterial blood oxygen tension and saturation and the development of a mild respiratory acidosis following ...