Michael DeBakey

Effect of Venous Pressure on Volume Pulsation

In a previous study it was noted that, with ligation of the main venous outlet from the lower extremity of the dog, a marked reduction in peripheral pulse volume occurred. 1 The present observations were made to throw some light on the mechanism of these changes. In 14 dogs the volume of pulsations in the hind foot was determined by adapting a specially constructed cellulose-acetate cup to the sensitive plethysmograph of Turner. 2 All observations were conducted under ether anesthesia and the operative procedure, consisting of isolation and ligation with silk of the femoral vein at the level of Pouparts ligament, was performed aseptically. Direct venous pressure determinations 3 were made in the saphenous vein at heart level before and after the ligation during the continuous determination of pulse volume. All observations were conducted under controlled atmospheric conditions, temperature 75 °F and humidity 50%. Observations were made on 2 groups of dogs: (1) 6 animals with intact sympathetic innervation, and (2)8 animals on which resection of the ipsolateral lumbar sympathetic ganglia and intervening chain had been performed 24 hours previously. Results. The results are graphically represented in Fig. 1. It may be observed that the rises in venous pressure in the femoral vein following ligation were 13.9 and 10.5 times the normal value in the non-sympathectomized and sympathectomized animals, respectively. The decreases in volume of pulsations following the ligations were 51.5% and 58.2%, respectively. The results obtained in each dog were essentially the same as the mean values, except in degree. It may also be observed that although the reactions in the sympathectomized and non-sympathectomized animals were essentially the same, the pulse volumes both before and after ligation were slightly lower in the sympathectomized than in the non-sympathectomized dogs, and that the corresponding venous pressures were slightly higher in the former.

Relative Protective Value of Alkaline Duodenal Juices Against Gastrojejunal Ulceration

A review of the voluminous literature which has now accumulated on the relative protective value of the alkaline duodenal juices in preventing ulcer formation reveals a bewildering maze of confusion. Much of this diversity of opinions and contradictory experimental results has been due in great measure to the observations and comparisons made by different investigators under varied and diverse circumstances. Because of the existing difficulty in drawing conclusions from the confusing and contradictory experimental results, this investigation was made. The investigation was divided into 4 groups of experiments: (1) Group 1—Severance of the pylorus and closure of both the gastric and duodenal ends and the reestablishment of continuity of the gastro-intestinal tract by gastrojejunostomy; (2) Group 2—Exactly the same procedure as in Group 1 but with the addition of transplantation of the common bile duct into the terminal ileum; (3) Group 3—Exactly the same procedure as was performed in the first group but with the addition of ligation and division of the accessory pancreatic (whenever it was found) and transplantation of main pancreatic duct into the terminal ileum; (4) Group 4—Exactly the same procedure as in Group 1 but with the addition of transplantation of both bile and pancreatic ducts into terminal ileum. Obviously all the groups are similar with the exception of one factor, the deviation of bile in one group, the deviation of pancreatic juice in another, and the deviation of both bile and pancreatic juice in the last group. Thus, because of the comparability of the 4 groups of experiments, any difference in results obtained can be accounted for by the one different factor characterizing each group. A total of 60 dogs was used in the experiment—20 in the first group, 20 in the second, 10 in the third, and 10 in the fourth group. In Group 1, 50% of animals living from 9 to 271 days postoperatively developed typical subacute and chronic ulcers.

Anticipating some difficulties during transfusion of unmodified blood

Abstract 1. 1. The lack of appreciation of the technical difficulties which may arise during the procedure of transfusion of unmodified blood is responsible for the majority of failures. 2. 2. These difficulties are outlined under four headings: 2.1. (a) Introduction of needles. 2.2. (b) Clotting in needles and tubing. 2.3. (c) Clotting of blood in conveying intermediary. 2.4. (d) Clotting of blood from unexpected delay. 3. 3. These difficulties are considered and discussed in detail from standpoint of usual cause and means of prevention. 4. 4. The proper performance of the introduction of the needles into the veins of recipient and donor is particularly emphasized and described. 5. 5. Clotting in the needles and tubing is the result of a poor flow of blood from the donor, old or defective rubber tubing, and improper care in previous cleansing and oiling. 6. 6. Clotting in the intermediary is due to insufficient familiarity with the type of instrument used, complicated valve mechanism, defective syringe, stagnation of blood, and improper care of the instrument. 7. 7. Stagnation of blood with predisposition toward clotting may result, due to unexpected delay caused by fainting of donor, disjointing of apparatus, or stoppage of the arterial supply by a too tight constrictor.