Three categories of membrane oxygenators are considered: passive flow, secondary flow induced by the mainstream, secondary flow induced by an external application of energy. The current status of mathematical methods for analysis of fluid mechanics, O2 and CO2 exchange for these categories are briefly reviewed. Emphasis is given to approximate ...

The complex blood flow patterns occurring in a trout secondary lamella were computed from a theoretical electrical model consisting of a two-dimensional array of unitary resistances representing the blood channels of the lamella. Estimates of oxygen uptake from water to blood were made by means of the standard conductance equations ...

The transfer of tritiated water across the isolated, artificially perfused guinea pig placenta was the subject of 21 experiments. The observed relationship between the flow rates and the relative transfer of water cannot be explained by a concurrent or pool-flow system. If the direction of the fetal flow is reversed, ...

The bilirubin titration point--the lowest bilirubin concentration at which loosely bound bilirubin could be demonstrated by Sephadex gel filtration--was determined in samples collected before, during, and on completion of 17 exchange transfusions as well as in the discarded and donor blood. The bilirubin titration point expressed either as bilirubin concentration ...

An exchange transfusion was performed preoperatively on a patient with sickle cell disease using a continuous-flow blood cell separator. An exchange of 2,825 ml red blood cells achieved a hemoglobin A level of 90.8 per cent. The continuous-flow blood cell separator appears to offer a safe and effective method of ...

In an anaesthetized dog an exchange transfusion was carried out with stroma-free haemoglobin solution. The total circulating blood volume was kept constant. The heart-syncronous changes in the thoracic electrical impedance (Zo) were measured before and after the exchange transfusion. Zo consists of a parallel connection of a tissue impedance (Zt) ...

The present investigation was designed to quantitatively assess the possible influence of countercurrent exchange on passive absorption from the small intestine of the dog. Villus blood flow was measured with a modification of the microsphere method. Simultaneously, the absorption from the gut lumen of five diffusible gases (H2, He, CH4, ...

The maxillary ostium is narrower when the subject is recumbent than when sitting. The oxygen content in the sinus is related to the patency of the ostium and to some extent to its size. A 90% gas exchange in the sinus normally requires only 5 minutes. The exchange is faster ...

The effect of blood exchange transfusion on the thyroid has been studied by serially establishing the effective thyroxine ratio (ETR). The ETR value is slightly increased in the newborn infant and the level is further augmented by blood exchange. Since the ETR level is lower in the transfused blood than ...

Because of inability to quickly locate donors to provide fresh heparinized blood, seven exchange transfusions were performed on four newborns with hemolytic disease due to Rhesus incompatibility using previously frozen erythrocytes suspended in albumin or heparinized, decitrated fresh frozen plasma. Platellets were added to one unit of previously frozen erythrocytes ...

Acute isovolemic anemia was produced in anesthetized chickens by serial exchanges of 6% dextran 70 equal to 1% of body weight to quantitate cardiovascular and metabolic parameters. When hematocrit (Hct) and hemoglobin (Hb) levels were reduced by 50% (from 33.3 to 16.3 vol %, and from 10.3 to 5.4 g/100 ...

Morphological evidence indicate that the main function of the endolymphatic sac is to act as a reabsorptive and defensive mechanism for the inner ear. This activity is markedly enhanced in labyrinthine trauma, such as injection of foreign particles into the labyrinth, blocking of the endolymphatic duct, and cryosurgical destruction of ...

1. The narrow passage within the petiole between thorax and abdomen is anatomically constructed so that counter-current exchange should retain heat in the thorax despite blood flow to and from the cool abdomen. 2. However, the counter-current heat exchanger can be physiologically circumvented. Exogenously heated bumblebees prevented overheating of the ...

CPD-adenine blood (adenine in a final concentration of 0.25 mmol/1) was used in exchange transfusions in four newborn infants. The amount of adenine in one exchange transfusion ranged from 27 to 29 mumol per kg bodyweight. The maximum P-adenine concentration during the exchange transfusions ranged from 4 to 8 mumol/1 ...

Red blood cells incubated in a physiological medium in which Li replaces Na (LiPSS) gain Li in exchange for Na and K. The rate of Li uptake is modestly but significantly increased in the spontaneously hypertensive rat (SHR) at 37 degrees C and at 22 degrees C. The slow rate ...

In two cases of hepatic coma following advanced liver cirrhosis exchange transfusions were applied with plasmapheresis. In both cases the general condition of patients improved and consciousness returned. After exchange transfusions with plasmapheresis the serum levels of bilirubin, urea and ammonia decreased. Using appropriately selected fluids for erythrocyte suspension it ...

A simple modification to the standard 'in-out' exchange transfusion technique is described which requires cannulation of the umbilical vein only, yet provides many of the theoretical and practical advantages of a 2-catheter arteriovenous technique. The advantages include a reduction of cardiovascular disturbance; a reduction of the inevitable pressure changes in ...

A disposable heat and moisture exchanger ("Artificial Nose") which is designed for use during endotracheal anaesthesia is described together with an evaluation of its performance. It has a low dead space, minimal resistance to gas flow, and is potentially capable of conserving 50 per cent of the respiratory water loss ...

Reye's syndrome (RS) consists of encephalopathy, fatty degeneration of viscera, and elevation of ammonia, certain amino acids, and liver enzymes in the blood. It is most characteristically a disease of children and has been considered to have a poor prognosis despite the use of various treatment regimens. Exchange transfusion (ET) ...

Human blood was contaminated with nitrostigmine, dimethoate and demeton-S-methyl sulfoxide. It was then dialysed, concentrations of organophosphates were determined and dialysance values calculated. The influence of blood exchange transfusion on poison elimination as well as on the cholinesterase activity of blood, brain and muscle was studied in rats poisoned with ...

The brain immediately surrounding 9L sarcoma and Walker 256 carcinosarcoma was evaluated, using radioactive water, albumin, red blood cells, urea, and sodium to quantitate isotopic exchange and permeability in the brain adjacent to tumor (BAT), normal brain, and, to a lesser extent, tumor. Exchange between blood and BAT for 14C-urea ...

It has been shown that gas exchange between the alveolar space and pulmonary capillary blood is affected by the pattern of airflow at the mouth in the non-homogeneous lung. The present theoretical study shows that even in the homogeneous lung, the pattern of airflow can affect gas exchange. When tidal ...

The probable toxic action is CO is on the cellular respiration, in which CO competes with O2 for cytochrome a3. Our studies indicate that a relatively high concentration of COHb (50%) does not interfere with the O2-carrying capacity of the blood. The dissolved CO in plasma, which is necessary for ...

We have utilized new methods of dialyzer-augmented whole blood and plasma exchange tranfusion in the treatment of hepatic coma. The method employs the new fast flow Buselmeier shunt so that the exchange can be done from a peripheral radial artery shunt site rather than a shunt site in a more ...

A mathematical model is described for the transport of gaseous or airborne particulate material between rooms along ventilated passageways. Experimental observations in three hospitals lead to a value of about 0.06 m.2/sec. for the effective diffusion constant in air without any systematic directional flow. The 'constant' appears to increase if ...

Fifty-nine male and female (pregnant and nonpregnant) normal control subjects were differentiated from 18 male and female obligate heterozygotes for classic PKU. The method of genotyping utilized midday semifasting blood P and T quantitated by ion-exchange chromatography, an empiric determinant, P-2/T, and a discriminant function (sigma), in which sigma = ...

1. The aim of this study was to define the factors influencing plasma separation from the continuous flow celltrifuge and to evaluate plasma as an alternative to whole blood for perfusion of exchange resins as part of a system of artificial liver support. 2. Studies in vitro showed the importance ...

Hemolysis was studied in 40 G-6-PD-deficient newborn infants, half of whom had bilirubin blood levels within the normal range whereas the others, who were hyperbilirubinemic, underwent exchange transfusion. Hemoglobin, hematocrit, hemopexin and haptoglobin showed no or little differences between either of the two groups and the controls. The findings confirm ...

The purpose of the present study was to quantitate the influence of countercurrent exchange on passive absorption of highly diffusible substances from the small intestine of the rabbit. The absorption of carbon monoxide, which is tightly bound to hemoglobin and therefore cannot exchange, was compared to the absorption of four ...

In 20 exchange transfusions with THAM-buffered ACD blood 5 ml. of 2% calcium gluconate (8 mg. elemental calcium) was injected after each 100 ml. of blood exchanged. Plasma ionized calcium decreased significantly during the procedure, although after each injection of calcium gluconate, levels returned briefly to normal. Ten minutes after ...

The ventricular space of rabbits was perfused with a low-viscosity silicone oil for the purpose of (1) collecting freshly secreted cerebrospinal fluid (c.s.f.) uninfluenced by diffusional exchanges with the brain and (2) studying passage of solutes from the blood into the brain, uncomplicated by exchanges with c.s.f. The freshly secreted ...

One hundred and fifty exchange transfusions, using citrated donor blood, were investigated to determine the mortality rate from the procedure. One infant died during manipulation of the catheter in the umbilical vein. Four infants died of combined causes including anemia, prematurity and elevated potassium in the donor blood. Sixty-two exchange ...

1. Respiratory exchange measurements may be used for gaining further evidence concerning the body changes during anemia, and are complementary to the hematological and histological data. 2. The heat production during anemia was slightly decreased. At the 3rd week it began to rise. 3. A protein-free liver extract has accelerated ...

The sickle cell trait (Hgb-AS) and G-6-PD deficiency are two genetic defects which increase the hemolytic susceptibility of erythrocytes. As these two traits are common in Nigeria, blood transfusions with such defective cells are frequently given. In this study, the immediate and long-term effects of using either normal blood or ...

The main function of the respiratory system is to draw air into the lungs to allow the exchange of gases with blood circulating to the lungs. This blood supplies the cells of the body with oxygen and removes the waste products of metabolism. Tissues of the respiratory tract are thin ...

This article examines the importance of information giving and its role in gaining informed consent from patients with sickle cell disease requiring exchange blood transfusion for the management of stroke. The rationale for the use of exchange blood transfusion in patients with sickle cell disease who have had a stroke ...

1. A study has been made, in the isolated, beating dog heart perfused with blood, of the transcapillary exchange of the following substances: [(3)H]water, (22)Na, (86)Rb, (36)Cl, [(14)C]urea, [(3)H]glycerol, [(3)H]glucose, [(14)C]sucrose and [(3)H]inulin.2. The method used to study the exchange was the ;indicator diffusion' technique. It consists in a rapid ...

A method is described for the measurement of total body exchangeable oxygen stores (TBO(2)). It is based on the dilution of the stable oxygen isotope, (18)O(2), by the body exchangeable oxygen stores under circumstances in which (18)O(2) steady-state equilibrium was evaluated simultaneously for both arterial and venous blood compartments. After ...

1. Inorganic phosphate was selectively removed from the circulating blood of five anaesthetized goats by means of columns of anion-exchange resin. Concentrations of other ions were unaffected by the column.2. Rates of inorganic phosphate extraction in excess of 5 m-moles/hr caused a fall in plasma inorganic phosphate of up to ...

An analysis is undertaken to determine the continuous distribution of circulation rates which would be necessary for a single tissue type to display a simple exponential response for the exchange of a solute with blood. It is shown that there can be no more than one real solution. This indicates ...

In the management and prevention of hemolytic disease of the newborn, exchange transfusions seem destined to remain the mainstay of therapy for some time to come. Our current knowledge of bilirubin metabolism has altered the indications for the procedure and introduced such useful new adjuncts to therapy as albumin infusions. ...

One hundred and fifty exchange transfusions, using citrated donor blood, were investigated to determine the mortality rate from the procedure. One infant died during manipulation of the catheter in the umbilical vein. Four infants died of combined causes including anemia, prematurity and elevated potassium in the donor blood. Sixty-two exchange ...

Laboratory studies have been made to evaluate two methods for removing ammonia from blood:-1 The twin-coil artificial kidney was found to produce significant reductions in the ammonia content of outdated human banked blood. After one passage through the coil, levels of up to 9 mug. of ammonia nitrogen per millilitre ...

It has been demonstrated experimentally that small numbers of a variety of different bacteria fail to survive or multiply in normal cow or human blood or in a mixture of blood and a suitable culture medium, owing to the binding of the magnesium ion and a protein component of the ...

Under ordinary conditions musculofascial cross-grafts made between pairs of rabbits of the same strain and species elicited classical host-homograft tissue interactions. When the cross-grafting was done 7 to 10 days after exchange transfusions leading to introduction of about 40 per cent of foreign blood, the classical host-homograft reaction failed to ...

The exchange of potassium between cells and plasma of heparinized human blood has been studied in vitro using the radioactive isotope K(42). The changes in cell and plasma specific activity are characteristic of a simple two-compartment system. The mean of seven determinations of the exchange rate at 38 degrees C. ...

1. Respiratory exchange measurements may be used for gaining further evidence concerning the body changes during anemia, and are complementary to the hematological and histological data. 2. The heat production during anemia was slightly decreased. At the 3rd week it began to rise. 3. A protein-free liver extract has accelerated ...