Control, monitor and alarm system for clinical application of a membrane oxygenator

Membrane oxygenators, now commercially available, are undergoing clinical trials as long-term (days) respiratory support devices for patients in potentially reversible respiratory failure. However, these devices must be used in an integrated system of controls, monitors and alarms if they are to be reliable and easy to operate in the clinical environment. This paper describes such a system. The tubing circuits for blood and for oxygen are described first. Next, details of the blood pump controls are presented. The system features servo control of pump speed to match blood inflow, and deactivation of the pump in the case of excessive output pressure. Gas circuit controls are described which allow the independent adjustment of both oxygen flow through the gas phase of the membrane lung and oxygen pressure developed at the inlet gas port. Audible alarms are provided for low blood inflow to the system, excessive blood outflow pressure, changes in oxygen flow and failure of the electric power supply to the system. In addition to pressure and flow monitors in the blood and gas circuits, blood oxygen saturation is continuously monitored at both input and output of the system. The membrane oxygenator system has proved to be reliable and easy to operate in both animal and human long-term perfusions.

Combination of membrane oxygenator support and pulmonary lavage for acute respiratory failure

A 24-year-old woman with chronic granulocytic leukemia and alveolar proteinosis required extracorporeal membrane oxygenator support for respiratory failure refractory to conventional therapy. During perfusion, each lung was lavaged with 10 L. of normal saline. The lavage led to marked clearing of the lungs and improvement in pulmonary function. Extracorporeal support was terminated successfully after 54 hours. The patient died 2 weeks later with bone marrow insufficiency and overwhelming sepsis. Pulmonary lavage is technically feasible during venovenous oxygenator bypass, and may be of value, since such lavage debrides alveoli as well as the bronchial tree. Because pulmonary lavage provides a possible means of improving pulmonary function, it seems worthy of consideration as an adjunct to membrane oxygenator support.

Steroid-protein interactions in bovine plasma

The binding of testosterone, corticosterone and 17alpha-hydroxyprogesterone by bull plasma protein was studied by equilibrium dialysis. Testosterone in bovine plasma was bound by a CBG-like protein and by a specific protein (testosterone-binding protein or TBP) of limited capacity and high affinity. The TBP was specific for C18 and C19 steroids with a 17 beta-hydroxy group. Precision of the steroid-protein binding measurements was tested and was satisfactory. The testosterone-binding capacity in bull plasma samples did not seem to be related to testosterone levels in peripheral plasma. Significant differences between bulls and cows with regard to the binding capacity were observed.

[Relationship between testosterone binding proteins and testosterone and LH plasma concentrations in the young bull]

Plasma levels of testosterone and LH were measured by radioimmunoassay from blood samples of young bulls of 9 to 15 months of age. The binding constants of specific testosterone binding plasma proteins were determined from the same samples. No significant difference of these values could be seen during the 25 hr. sampling period, contrary to large fluctuations in testosterone and LH plasma concentrations. But, the testosterone binding constants values were significantly lower after puberty (15 months) than at 9 and 12 months of age.

A rapid, quantitative determination of clottable fibrinogen unaffected by heparin

A turbidimetric assay for clottable plasma fibrinogen which is not sensitive to heparin or Pyran inhibition is described. The basis of the assay is the substitution of Reptilase-R for the thrombin usually employed. The assay correlates very well with a thrombin turbidimetric method and also has other advantages, including better stability of the clotting enzyme and more rapid attainment of equilibrium.

Vicryl (Polyglactin 910): a new synthetic absorbable suture in ophthalmic surgery. A preliminary study

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Multiple congenital defects associated with trisomy for the short arm of chromosome 4

The clinical and cytogenetic findings of a female infant with multiple congenital anomalies and trisomy for the short arm of chromosome 4(46,XX,21p+) are described. The abnormal chromosome was inherited from the father who had a balanced translocation between the short arm of chromosome 4 and the short arm of chromosome 21. Clinical features are compared with those of one definite and one probable previously described case of trisomy for the short arm of chromosome 4. It is suggested that a clinical syndrome associated with +4p eventually may be identified.

Freeze-fracture replication of melanocytes and melanosomes

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