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Mixed Venous (mixed + venous)

Distribution by Scientific Domains
Medical Sciences80%

Terms modified by Mixed Venous

  • mixed venous oxygen saturation
    		•

    Selected Abstracts

    OASIS® wound matrix versus Hyaloskin® in the treatment of difficult-to-heal wounds of mixed arterial/venous aetiology

    INTERNATIONAL WOUND JOURNAL, Issue 1 2007
    Marco Romanelli
    Abstract Mixed arterial/venous (A/V) ulcers are difficult to treat and slow to heal likely as a result of deficiencies in molecular and cellular elements in the wound bed. Recently, biomaterials have been developed that replace extracellular matrix (ECM) molecules and growth factors critical to the normal healing process. In this study, the effects of OASIS® and Hyaloskin® were evaluated to compare the effectiveness of these two ECM-based products in their ability to achieve complete wound healing of mixed A/V ulcers. After 16 weeks of treatment, patients in each group were evaluated on four criteria: complete wound healing, time to dressing change, pain and comfort. Complete wound closure was achieved in 82·6% of OASIS® -treated ulcers compared with 46·2% of Hyaloskin® -treated ulcers (P < 0·001). Statistically significant differences favouring the OASIS® treatment group were also reported for time to dressing change (P < 0·05), pain (P < 0·05) and patient comfort (P < 0·01). Overall, OASIS® was superior to Hyaloskin® for the treatment of patients with mixed A/V ulcers, a population in which standard treatment options largely consist of moist wound dressings and compression therapy is typically not an option. OASIS® is a useful and well-tolerated treatment for mixed A/V ulcers that has the potential to improve quality of life and reduce costs associated with standard of care. [source]

    The Contribution of Chemoreflex Drives to Resting Breathing in Man

    EXPERIMENTAL PHYSIOLOGY, Issue 1 2001
    Safraaz Mahamed
    The contribution of automatic drives to breathing at rest, relative to behavioural drives such as ,wakefulness', has been a subject of debate. We measured the combined central and peripheral chemoreflex contribution to resting ventilation using a modified rebreathing method that included a prior hyperventilation and addition of oxygen to maintain isoxia at a PET,O2 (end-tidal partial pressure of oxygen) of 100 mmHg. During rebreathing, ventilation was unrelated to PET,CO2 (end-tidal partial pressure of carbon dioxide) in the hypocapnic range, but after a threshold PET,CO2 was exceeded, ventilation increased linearly with PET,CO2. We considered the sub-threshold ventilation to be an estimate of the behavioural drives to breathe (mean ± S.E.M. = 3.1 ± 0.5 l min,1), and compared it to ventilation at rest (mean ± S.E.M. = 9.1 ± 0.7 l min,1). The difference was significant (Student's paired t test, P < 0.001). We also considered the threshold PCO2 observed during rebreathing to be an estimate of the chemoreflex threshold at rest (mean ± S.E.M. = 42.0 ± 0.5 mmHg). However, PET,CO2 during rebreathing estimates mixed venous or tissue PCO2, whereas the resting PET,CO2 during resting breathing estimates Pa,CO2 (arterial partial pressure of carbon dioxide). The chemoreflex threshold measured during rebreathing was therefore reduced by the difference in PET,CO2 at rest and at the start of rebreathing (the plateau estimates the mixed venous PCO2 at rest) in order to make comparisons. The corrected chemoreflex thresholds (mean ± S.E.M. = 26.0 ± 0.9 mmHg) were significantly less (paired Student's t test, P < 0.001) than the resting PET,CO2 values (mean ± S.E.M. = 34.3 ± 0.5 mmHg). We conclude that both the behavioural and chemoreflex drives contribute to resting ventilation. [source]

    Vasopressin decreases intestinal mucosal perfusion: a clinical study on cardiac surgery patients in vasodilatory shock

    ACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 5 2009
    A. NYGREN
    Background: Low to moderate doses of vasopressin have been used in the treatment of cathecholamine-dependent vasodilatory shock in sepsis or after cardiac surgery. We evaluated the effects of vasopressin on jejunal mucosal perfusion, gastric-arterial pCO2 gradient and the global splanchnic oxygen demand/supply relationship in patients with vasodilatory shock after cardiac surgery. Methods: Eight mechanically ventilated patients, dependent on norepinephrine to maintain mean arterial pressure (MAP) ,60 mmHg because of septic/post-cardiotomy vasodilatory shock and multiple organ failure after cardiac surgery, were included. Vasopressin was sequentially infused at 1.2, 2.4 and 4.8 U/h for 30-min periods. Norepinephrine was simultaneously decreased to maintain MAP at 75 mmHg. At each infusion rate of vasopressin, data on systemic hemodynamics, jejunal mucosal perfusion, jejunal mucosal hematocrit and red blood cell velocity (laser Doppler flowmetry) as well as gastric-arterial pCO2 gradient (gastric tonometry) and splanchnic oxygen and lactate extraction (hepatic vein catheter) were obtained. Results: The cardiac index, stroke volume index and systemic oxygen delivery decreased and systemic vascular resistance and systemic oxygen extraction increased significantly, while the heart rate or global oxygen consumption did not change with increasing vasopressin dose. Jejunal mucosal perfusion decreased and the arterial-gastric-mucosal pCO2 gradient increased, while splanchnic oxygen or lactate extraction or mixed venous,hepatic venous oxygen saturation gradient were not affected by increasing infusion rates of vasopressin. Conclusions: Infusion of low to moderate doses of vasopressin in patients with norepinephrine-dependent vasodilatory shock after cardiac surgery induces an intestinal and gastric mucosal vasoconstriction. [source]

    Cardiac Output Technologies with Special Reference to the Horse

    JOURNAL OF VETERINARY INTERNAL MEDICINE, Issue 3 2003
    Kevin T.T. Corley
    Critical illness, anesthesia, primary cardiovascular disease, and exercise may result in marked hemodynamic alterations. Measuring cardiac output (CO) is central to defining these alterations for both clinician and researcher. In the past 10 years, several new methods of measuring CO have been developed for the human medical market. Some of these methods are now validated in the horse and are in clinical use. The Fick method has been used in equine research for more than a century. It depends on simultaneous measurement of mixed venous (pulmonary arterial) and peripheral arterial oxygen content and oxygen uptake by the lungs. The technique is technically demanding, which restricts its clinical use. Indicator dilution techniques, with indocyanine green, cold (thermodilution), or lithium as the marker, have also been widely used in the horse. The indocyanine technique is cumbersome, and thermodilution requires right heart catheterization, which is not a benign procedure, making both of these methods less than ideal for clinical use. Lithium dilution requires catheterization of a peripheral artery and a jugular vein. It has recently been validated in anesthetized adult horses and neonatal foals. Doppler echocardiography is a noninvasive ultrasound-based technique. More accurate measurements are obtained with transesophageal than with transthoracic measurements; however, both methods require considerable technical expertise. Bioimpedance and pulse contour analysis are 2 new methods that have yet to be validated in the horse. With the currently available technology, lithium dilution appears to be the method of measuring CO best suited to the equine clinic. [source]

    Lower limb ulceration: a detailed study of aetiology in 555 patients

    BRITISH JOURNAL OF SURGERY (NOW INCLUDES EUROPEAN JOURNAL OF SURGERY), Issue 4 2000
    J. Naik
    Background: The purpose of the study was to investigate the aetiology of lower limb ulceration. Methods: The aetiology of lower limb ulceration was reviewed in 555 patients with 689 ulcerated limbs referred to a single-visit leg ulcer clinic. Results: The mean age of the patients was 70 (range 27,95) years and 335 (60 per cent) were women. The aetiology of the ulceration in 689 limbs was venous in 496 (72 per cent), arterial in 14 (2 per cent), mixed venous and arterial in 101 (15 per cent), with other causes in 78 (11 per cent). Of the 496 venous ulcers, 261 (53 per cent) had isolated superficial reflux, 233 (47 per cent) had deep venous reflux, of which 165 (71 per cent) had full-length and 68 (29 per cent) segmental reflux, and two patients had isolated perforator reflux. Deep venous obstruction was present in 16 limbs (3 per cent) with venous ulcers and 14 of these demonstrated continuous flow in the long saphenous vein (LSV). Of the 261 ulcerated legs with isolated superficial reflux, 197 (75 per cent) had LSV reflux only, 22 (8 per cent) had short saphenous vein (SSV) reflux only and 41 (16 per cent) had combined LSV and SSV reflux. Of those with LSV reflux, 65 per cent had a medial malleolar ulcer and 20 per cent had a lateral malleolar lesion. Of those with SSV reflux, 62 per cent had a lateral malleolar ulcer and 38 per cent had a medial malleolar ulcer. Conclusion: Half of the ulcerated legs have superficial venous reflux; these combined with the superficial and segmental deep venous reflux group comprise the 65 per cent of patients who may benefit from superficial venous surgery. Continuous flow in the LSV should alert the clinician to deep venous obstruction, in which circumstance compression therapy should be used with extreme caution. Duplex is central to the investigation of the ulcerated leg. © 2000 British Journal of Surgery Society Ltd [source]