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 296,593 document(s) hit in 31,850,051 MEDLINE articles (0.03 seconds)

Four resuscitator bags were studied to see if the delivered fractional oxygen percentage (FDO2) could be affected by manually controlling the inherent reexpansion rate of the bag so as to allow a greater entrainment of oxygen rather than air into the bag. Flow rates of oxygen into the bag were varied: 5, 10, 15, and 20 liter/min. For each flow rate, bag refill (reexpansion) times were varied: 1, 2, 4 sec. The results show that such a maneuver will effectively increase the FDO2 of the bags at all flow rates tested--in certain instances to values greater than 0.8. This maneuver would be important to resuscitation situations where it is desirable to achieve better patient oxygenation.
Crit Care Med
PMID:A simple method to increase the FDO2 of resuscitator bags. 27 97

As part of the development of a life support stretcher for transportation of critically ill patients, a portable ventilation system was developed. This system was used successfully during transportation of 6 of 11 patients who required ventilatory assistance and who were being considered for extracorporeal membrane oxygenator support. Immediately after transportation, PaCO2 values were significantly lower (p less than 0.05) in patients ventilated with this system, when compared to PaCO2 values of the remaining 5 patients in whom ventilation was assisted with a 2-liter anesthesia bag (PaCO2 = 58.7 +/- 3.6). This system offers significant advantages over other presently manufactured systems, including low cost, portability, and efficiency in terms of oxygen utilization. (Manual ventilation is supplied so that no auxiliary electrical power supply is necessary.) Positive end-expiratory pressure (PEEP) can be varied by 2.5 cm H2O increments using a commercially available, weighted ball valve. In addition, it has been useful for transporting patients with acute respiratory failure within the hospital for therapeutic maneuvers or diagnostic studies.
Crit Care Med
PMID:A portable, low cost ventilation system for transportation of patients with severe acute respiratory failure. 27 98

This study examined pulpal blood flow and oxygen consumption by the dental pulps of dogs. Blood flow was measured by the radioactive microsphere method and oxygen uptake was determined by the indirect Warburg approach. These variables were assessed 2 days after the canine teeth had been exposed and treated with either a cotton pellet impregnated with 1 per cent prednisolone or normal saline. The analysis indicated that the pulpal blood flow as well as the oxygen consumption did not differ between the steriod-treated tooth and the corresponding saline-treated tooth in the same jaw.
Oral Surg Oral Med Oral Pathol 1978 May
PMID:Blood flow and oxygen consumption in steroid-treated dental pulps. 27 97

Rats were exposed 24 hours a day to carbon dioxide, 8 +/- 1%, during 2 and 4 weeks under normoxic conditions (21% oxygen). On the last day, blood was taken from the abdominal aorta under anesthesia. Leukocyte and erythrocyte counts, hemoglobin concentration, and mean cell volume were electronically measured. Hematocit and Wintrobe indexes were calculated. Leukocyte differential counts and peroxidase activity were determined on blood smears. After 4 weeks of hypercapnia, a slight decrease of neutrophilic granulocytes was observed. In mature polymorphs, peroxidase activity (cytochemically demonstrated) simultaneously decreased. Erythrocyte counts and mean cell volume remained unchanged. The most important hematological disturbance was an hemoglobin concentration drop. Consequently, it was concluded that an hypochromic anemia characterized the permanent normoxic hypercapnia in rats.
J Med 1978
PMID:Blood effects of permanent normoxic hypercapnia in conventional rats. 28 61

Multiple blood specimens with different leukocyte counts from two patients with extreme leukocytosis secondary to leukemia and unexplained hypoxemia were tonometered with a gas of known oxygen concentration and the decay of oxygen tension (PO2) was measured over time. The decay in PO2 in the first 2 minutes for blood with leukocyte counts of between 55.2 X 10(3)/mm3 and 490.0 X 10(3)/mm3 ranged from 13 to 72 torr. The degree of PO2 decay was blunted by placing the blood on ice and was obliterated by adding potassium cyanide. Thus, extreme leukocytosis secondary to leukemia can cause spurious hypoxemia and spurious lowering of the mixed venous PO2 due to oxygen consumption by leukocytes ("leukocyte larceny").
Am J Med 1979 Nov
PMID:Leukocyte larceny: a cause of spurious hypoxemia. 29 9

The energy requirements for T-cell-mediated cytolysis have been investigated. Cytolytic thymus-derived lymphocytes (CTL) were generated in vitro in mixed leukocyte cultures and assayed for cytotoxicity on 51Cr-labeled mastocytoma target cells. Cytolysis was only slightly reduced in the absence of exogenous glucose (less than 5 micrometer) or under conditions of extreme hypoxia (less than 0.2 micrometer oxygen). Furthermore, neither the glucose analogues 2-deoxy-D-glucose and 5-thio-D-glucose nor the respiratory antagonists sodium azide and 2,4-dinitrophenol were very effective inhibitors of cytolysis when used individually. However, these glucose analogues were highly effective in inhibiting cytolysis in the absence of oxygen, and the respiratory antagonists inhibited cytolysis to a much greater extent in the absence of glucose. In addition, synergistic effects were observed when the glycolytic and respiratory inhibitors were combined. Taken together, these results indicate that T-cell-mediated cytolysis is an energy-dependent process which can be supported by either oxidative or glycolytic energy pathways.
J Exp Med 1977 Sep 01
PMID:Energy metabolism and T-cell-mediated cytolysis. I. Synergism between inhibitors of respiration and glycolysis. 30 4

Changes in myocardial oxygen supply were evaluated in 19 patients following coronary by-pass surgery (CBS) for angina pectoris (AP). A symptom limited maximal functional graded exercise test (GXT) was performed before and 2-19 (X 7.5) months following CBS. After surgery the patients were urged to resume full activity and were individually managed in a 10-week "at home" exercise program. Increases were demonstrated for predicted oxygen uptake and work load (p less than .002), and rate pressure product (p less than .02) following CBS, suggesting increased myocardial blood flow. Terminal heart rate showed no significant increase. Of 16 patients exhibiting ST segment depression ( greater than or equal to .1 mV) with AP during GXT before surgery, 10 cases experienced total relief of both of these signs after surgery. A correlation between the pre-operative number of occluded coronary arteries (greater than 50%) and the degree of exercise induced ST segment depression revealed no significant trend. Additionally, no significant relationship was found between post-operative GXT results and the number of by-pass grafts performed on each patient. This study supports the premise that the effectiveness of CBS, in improving functional capacity, can be objectively evaluated by a non-invasive functional GXT.
Med Sci Sports 1977
PMID:Functional capabilities following coronary bypass surgery. 30 83

Studies on the radionecrosis of mouse tails demonstrate the following modifications to the dose necessary for necrosis in 50 per cent of tails (the ND50): (a) There is very little reduction in ND50 values for irradiated lengths of tail from 2 cm to almost the whole tail, but there is a sharp increase in dose for lengths less than 1.5 cm. (b) The ND50 is high for unanesthetized mice irradiated in air, due to tissue hypoxia. (c) The hypoxia can be reduced by varying amounts by applying heat to the tail, or by flowing oxygen over the tail surface, or by anesthetizing the animal. (d) The ingress of oxygen through the surface can be reduced by placing a clamp round the proximal tail. These features are discussed with reference to the state and possible position of the target cells, and to the use of this assay technique in comparative studies.
Int J Radiat Biol Relat Stud Phys Chem Med 1978 Jan
PMID:Radionecrosis of normal tissue: studies on mouse tails. 30 49

Fifty hemiparetic subjects were selected from a population of 250 patients according to criteria forsuitable candidates for peroneal stimulation. The patients received from 10 to 120 hours of treatment during 2--5 weeks. The therapeutic results obtained were classified into four groups, ranging from none to excellent improvement of voluntary movement and reduction of spasticity. The clinical results were correlated to different variables where time from lesion, spasticity, and extent of treatment appeared to be the most important ones. The percentage of excellent results decreased with increasing time from lesion and spasticity, and increased with increasing treatment. Orthotic validity (i.e. the beneficial effect of the orthosis) was observed in 76% of the selected cases and in most of them it was very significant. Preliminary tests performed on 9 subjects showed that in cases with orthotic validity the peroneal brace slightly reduces the oxygen consumption of patients and improves their motivation. This work gives a more quantitative perspective of the validity of functional peroneal stimulation and a better indication of criteria for patient selection. The overall validity of an electronic peroneal brace appears to apply to 15% of the total ambulatory hemiparetic population and its therapeutic value is relevant in two-thirds of such cases if sufficient treatment is provided. Application of functional electrical stimulation to non-ambulatory subjects in the acute phase may however lead to a higher percentage of cases of therapeutic validity.
Scand J Rehabil Med 1979
PMID:Clinical experience of electronic peroneal stimulators in 50 hemiparetic patients. 31 98

THE THREE GOALS OF CARDIAC ASSISTANCE ARE: (1) To maintain systemic blood flow; (2) To reduce cardiac work and tension development; and (3) To increase oxygen availability to the heart. Toward these ends, various devices and techniques have been developed, including several different types of vascular shunts in combination with or without extracorporeal oxygenation of blood, implantable auxiliary ventricle and augmentation of diastolic pressure by direct counter pulsation of blood through femoral cannulae or intra-aortic balloon.The sequenced counter pulsator is an external cardiac assist device being developed for the therapy of low output syndromes. Investigation in the laboratory has shown that it is capable of increasing cardiac output and diastolic systemic pressure with concomitant reduction in left ventricular end-diastolic pressure. Therefore, it appears to be clinically useful in patients with low cardiac output syndromes.
Yale J Biol Med
PMID:The sequential external counter pulsator: a circulatory assist device. 32


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