Biomedical subjects

I Dawidson

Publications and source records attributed to I Dawidson.

82 records · Page 5Linked to original sources

PubMed1979

Hemodilution and oxygen transport to tissue in shock.

Shock was induced in sixty dogs by laparotomy, splenectomy and exteriorization of the small intestine for three hours. Resuscitation following different plasma substitutes was assessed by measuring hemodynamic parameters (mean arterial blood pressure, plasma volume, oxygen consumption, cardiac output and hematocrit). To justify a comparison, the colloids (albumin, ACD-plasma, dextran 40, dextran 70, gelatine) were given at the same concentration and dose (3.5 % solutions in saline at a dose of 1.5 g/kg or 43 ml/kg). Ringer's acetate was given in a three times larger volume (129 ml/kg). After reposition of the intestine, the infusion was given over a 20 minute period. During shock hemoconcentration developed, increasing from 50 to 59 % in hematocrit; mean arterial blood pressure dropped from 144 to 95 mm Hg; plasma volume decreased to 67 %; total body oxygen consumption decreased to 59 % and cardiac output to 21 % of initial values. Reposition of the intestine did not in itself improve these values. Ringer's acetate was effective up to about 30 minutes after infusion but did not differ from no infusion at four hours. Gelatine and ACD-Plasma had a similar effect up to two hours. Albumin, dextran 40 and dextran 70 increased and maintained plasma volume and oxygen consumption at preexperimental levels for up to at least four hours. It is concluded that a single infusion of albumin, dextran 40 or dextran 70 is superior to ACD-plasma gelatine or Ringer's acetate in restoring and maintaining oxygen consumption and hemodynamic functions, when given in comparable doses and volumes.

Animals↗

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↗

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

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↗

PubMed1975