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Biomedical subjects

M S Litwin

Publications and source records attributed to M S Litwin.

At least 109 records · Page 6Linked to original sources
PubMed1979

Filtration characteristics of the polyester fiber micropore blood transfusion filter.

The filtration characteristics of a new polyester fiber (Fenwal II) micropore blood transfusion filter were investigated. Filtration of stored human whole blood and packed cells resulted in return of screen filtration pressure (SFP) of the blood to normal. Increased filter weights verified removal of large amounts of debris and microaggregates from the blood. Filtration of large quantities of blood accomplished at very high flow rates did not adversely affect the composition of the filtered blood. We conclude that the polyester fiber (Fenwal II) micropore blood transfusion filter is effective in removing microaggregates from stored whole blood and packed cells. It has a high volume capacity, allows rapid flow, and is reliable during pressure transfusion.

Blood Banks↗
PubMed1979

Pulmonary structural changes following microembolism and blood transfusion. A light and electron microscopic study.

Blood stored under standard blood band conditions develops microaggregates of platelets and leukocytes. Dog lungs were studied by light and electron microscopy at intervals from 48 hours to six days following exchange transfusions of sublethal volumes of such microaggregate-rich blood through either standard or Dacron wool (Swank) transfusion filters. After transfusion through standard filters, the pulmonary microvasculature was extensively occluded by microemboli. Swelling of capillary endothelial cells, interstitial and alveolar edema, and hypoxic changes in types I and II alveolar epithelial cells were noted. Changes then progressively resolved. These detrimental changes were prevented when microaggregates were removed by Dacron wool (Swank) filters. Mechanical occlusion of the pulmonary vasculature probably plays a minor role in initiating the structural changes observed. Release of lysosomes from disintegrating microaggregates is believed to be the significant factor initiating a chain of events leading to progressive pulmonary damage.

Animals↗
PubMed1978

Increased pulmonary arteriovenous shunting in humans following blood transfusion. Relation to screen filtration pressure of transfused blood and prevention by Dacron wool (Swank) filtration.

Transfusion through standard filters to dogs of stored blood containing microaggregates results in an increase in pulmonary arteriovenous shunting (Qs/Qt) and a decreased diffusion capacity of the lung for O2. These effects are due to microemboli that pass the filters and are prevented by use of Dacron wool (Swank) micropore transfusion filters. It was the purpose of this study to determine whether alterations in pulmonary shunting occur in humans following transfusions of stored blood through standard transfusion filters. In eight patients transfused over 20% of blood volumes through standard filters, Qs/Qt and alveolar-arterial O2 tension differences increased significantly. These changes did not occur in patients transfused comparable amounts of blood through Dacron wool (Swank) filters or in patients transfused less than 20% of blood volumes. A direct correlation was found between the absolute percent change in Qs/Qt and the quantity of microaggregates passing the filter and present in the transfused blood. It is concluded that removal from stored blood of microaggregates by administration of the blood through effective micropore transfusion filters prevents an increase in Qs/Qt caused by administration of such material.

Adult↗
PubMed1977

Polyurethane foam (Bentley) micropore blood transfusion filter: filtration characteristics.

Stored human blood of varying age was passed through polyurethane foam (Bentley) micropore blood transfusion filters. Passage through these filters resulted in decreased screen filtration pressure (SFP) of the blood and increased filter weights. Numerous microaggregates were removed and SFP returned to normal after filtration. Occlusion of the filter occurred after passage of only 2 units of whole blood. On the basis of this research, we conclude that polyurethane foam (Bentley) micropore blood transfusion filters are effective in removal of microaggregates from stored human blood. Because the filtering capacity is not great, it is recommended that when these filters are used during transfusion a new filter be used for each unit of blood administered.

Blood Preservation↗
PubMed1977

Progression and resolution of changes in pulmonary function and structure due to pulmonary microembolism and blood transfusion.

It was the purpose of this research to define the progression over several days of changes in pulmonary function and structure and to document the phases of recovery following transfusions to dogs of sublethal quantities of stored blood containing microaggregates. Ten dogs underwent partial exchange transfusions averaging 60% of blood volume through standard blood transfusion filters. Average screen filtration pressure (SFP) of the blood was 85 mm Hg. Pulmonary hypertension did not develop, but there were striking decreases in O2 consumption, increases in Qs/Qt and decreases in Do2. Changes became progressively more marked over the first 48 to 72 hours after the transfusions. Pulmonary function of surviving animals returned nearly to normal by the sixth day after transfusions. Pathologic examinations of the lungs of animals sequentially sacrificed over 6 days showed intravascular microemboli, alveolar cell hyperplasia and interstitial and alveolar pulmonary edema. Progressive recovery was associated with progressive resolution of all detrimental changes. In 6 animals exchange transfused 100% of their blood volumes through dacron wool (Swank) filters and in three control animals that were not transfused, there were no significant changes in pulmonary function or structure. These experiments define the progression of deterioration and recovery over 6 days of pulmonary function in dogs after sublethal pulmonary microembolism occurring during blood transfusion.

Animals↗
PubMed1976

Filtration characteristics of polyester mesh (Pall) micropore blood transfusion filter.

Stored human blood of varying age was passed through polyester mesh (Pall) micropore blood transfusion (pore size, 40 mu). Passage through the filter resulted in decreased screen filtration pressure (SFP) of the blood and increased filter weight. Mumerous microaggregates were removed, but SFP did not return to normal after filtration. On the basis of this research, we conclude that polyester mesh micropore blood transfusion filters are not as effective as Dacron wool (Swank) transfusion filters in removal of micro-aggregates from stored human blood. If a polyester mesh filter must be used, it is recommended that once occlusion of the filter has occurred, the filter should then be discarded and another inserted.

Blood Preservation↗
PubMed1976

Gunshot wounds of the abdomen. A review of 277 cases.

During a five-year period from July 1968 throuhgh June 1973, 277 abdominal gunshot wounds (GSWs) occurred, the overall fatality of which was 10%. Abdominal exploration was done in all patients. No intra-abdominal injury was found in 40 patients (14%) and no death occurred in this group. There were 28 fatalities (12%) in 237 patients (86%) who had intra-abdominal injuries. Morbidity and mortality were related not only to the number of organs injured, but also to specific organs injured. The leading cause of early death was hypovolemia due to major vessel injuries. Septicemia was the most common cause of death if the patient survived the first 24 hours of hospitalization. Penetrating abdominal stab wounds and gunshot wounds must be considered separately, and mandatory routine abdominal exploration for all penetrating gunshot wounds is advised. In stab wounds to the abdomen, conservative management may be preferable.

Abdominal Injuries↗
PubMed1976

Microaggregate formation in stored human packed cells: comparison with formation in stored whole blood and a method for their removal.

Experiments were performed to compare the formation of microaggregates in stored human whole blood (WB) with that in stored packed cells (PC) and also to compare the effectiveness of standard blood transfusion filters with dacron wool (Swank) micropore transfusion filters in removing such microaggregates. After 5, 10, 15 and 20 days of storage SFP and debris weights of PC's were considerably greater than those of matched WB samples. Passage of either WB or PC's through standard blood transfusion filters resulted in small decreases in SFP and debris weights. Passage of either WB or PC's through dacron wool (Swank) transfusion filters led to striking and highly significant decreases in both SFP and debris weights. When stored PC's were diluted to the same hematocrits as their corresponding WB samples, SFP remained considerably elevated above those of the WB samples. On the basis of this research, it is concluded that centrifugation of blood during component separation leads to a significant increase in microaggregate formation over and above that which progressively occurs during storage and that the risk of pulmonary microembolization during transfusion with stored PC's is greater than that during WB transfusion. For this reason, dacron wool (Swank) filters should always be used when PC's are being transfused.

Blood Preservation↗
PubMed1975

Topical chemotherapy of lentigo maligna with 5-fluorouracil.

Three patients with biopsy-proven lentigo maligna were treated with topical 5-fluorouracil. Treatment consisted of twice daily application of 5% 5-fluorouracil cream for 13, 6, and 9 weeks, respectively. Two patients demonstrated presence of invasive melanoma; in one the melanoma was evident before chemotherapy, and in the other the lesion became evident after chemotherapy. In both the lentigo was treated topically and the melanoma excised locally. Posttreatment followup times through April 1, 1974 have been 42, 24, and 22 months, respectively. There has been no evidence of metastases in any patient. Topical chemotherapy with 5-fluorouracil cream appears to offer an encouraging alternative method of therapy for lentigo maligna of the face.

Aged↗
PubMed1975

Pulmonary microembolism associated with massive transfusion: I. Physiologic effects and comparison in vivo of standard and dacron wool (swank) blood transfusion filters in its prevention.

Pulmonary microembolism of microaggregates associated with massive blood transfusion may be a cause of post-traumatic pulmonary embolism. The purpose of this study was to investigate in the dog the influence on certain physiologic parameters of transfusion of blood containing platelet: white blood cell: fibrin (PWF) aggregates and to evaluate the effects of using blood transfusion filters of varying pore sizes during such transfusions. Exchange transfusions of approximately twice blood volume were performed in three groups of animals. Screen filtration pressure measurements verified the presence of large numbers of PWF aggregates in the transfusions. When no transfusion filters or standard commercially available blood transfusion filters of pore size 170 mu were used, experimental animals developed pulmonary hypertension, a decrease in total body 92 consumption, and metabolic acidosis. Interposition of Dacron wool (Swank) blood transfusion filters prevented these changes.

Animals↗
PubMed1975

Pulmonary microembolism associated with massive transfusion: II. The basic pathophysiology of its pulmonary effects.

In animals pulmonary hypertension, a decrease in total body O2 consumption and metabolic acidosis occur after transfusion of blood with an elevated screen filtration pressure (SFP) through standard blood transfusion filters. The purpose of this study was to define in detail the pulmonary abnormalities that develop following transfusion of blood with an elevated SFP through standard blood transfusion filters. Exchange transfusions of approximately twice blood volume were administered through standard commercially available blood transfusion filters (measured pore size--200 microns) to 6 animals. SFP measurements verified the presence of large numbers of aggregates in the transfusions. Although filters reduced SFP of the stored blood somewhat, numerous microaggregates passed the filters, and post-filtration SFP remained high. After transfusion average O2 consumption decreased to 77% of normal and metabolic acidosis developed. Pulmonary arterial hypertension was associated with an increase in pulmonary shunting of blood and a decrease in pulmonary diffusing capacity. The presence of extensive numbers of microemboli in the pulmonary arteriolar and capillary bed was confirmed by microscopic examination of lung tissue.

Acidosis↗
PubMed1975

A comparison in vivo dacron wool (Swank) and polyester mesh (Pall) micropore blood transfusion filters in the prevention of pulmonary microembolism associated with massive transfusion.

Experiments were performed to compare the effectiveness in vivo of the two most widely used micropore blood transfusion filters in preventing detrimental physiologic changes associated with transfusion of microaggregate-containing blood. Exchange transfusion with stored blood having an elevated screen filtration pressure (SFP) through polyester mesh (Pall) filters (Group PM) was followed by decreases in arterial blood pH and O2 consumption, increases in arterial blood pyruvate and lactate concentrations, and a decrease in pulmonary DO2. The lungs of 5 of 6 animals revealed emboli far out in the pulmonary microcirculation. These changes did not occur in animals transfused through dacron wool (Swank) filters (Group DW). Even though an increase after transfusion in pulmonary Qs/Qt in Group PM did not achieve statistical significance when compared to pretransfusion Qs/Qt, it was significantly higher than that in animals in Group DW. Both filters removed considerable quantities of microaggregates; however, the polyester mesh (Pall) filters permitted passage of small microaggregates and development of ditrimental physiologic changes. Dacron wool (Swank) filters completely removed measurable microaggregates and detrimental changes did not occur.

Animals↗
PubMed1975

Effect of intravascular cellular aggregate dissolution in postoperative patients.

It was the purpose of this study to confirm whether the increase in packed cell (PC) viscosity that occurs in humans after elective surgery is accompanied by a decrease in total body O2 consumption as previously noted in animals, and further to define the effect of resolution of intravascular cellular aggregates (ICA) on these parameters. Thirty nine patients were studied. Total body O2 consumption was 76% of normal 6 hours postop, 81% of normal 24 hours postop and 87% of normal 48 hours postop. Twenty four hours after operation PC viscosity and increased markedly. Saline infusion had no significant effect on total body O2 consumption or PC viscosity, either pre- or postop, but WB viscosity decreased linearly in proportion in the drop in hematocrit. Resolution of ICA by dextran-40 infusion was associated with return of total body O2 consumption and PC viscosity to normal; a decrease in WB viscosity was disproportionately greater than would have been seen had the decrease been due solely to the drop in hematocrit. It is concluded that in humans surgical trauma causes an increase in PC viscosity and microcirculatory impairment as evidenced by a decrease in total body O2 consumption. Resolution of ICA by dextran-40 infusion reverses that detrimental changes.

Animals↗