Traumatic shock. XXI. Effectiveness of an antibiotic in experimental hemorrhagic shock.

Hemorrhagic shock was produced in unanesthetized,” healthy mongrel dogs by bleeding from a femoral artery (exposed without sterile precautions through a groin incision under local procaine anesthesia) to an elevated reservoir adjusted to maintain the arterial pressure at 30 mm. Hg (I). Bottles, tubing and cannulae were freshly cleaned but not sterile. Heparin (50 mg.) was placed in the reservoir and tubing. Room temperature was maintained at 65’ to 7o°F. The duration of the period of controlled hypotension was determined by the capacity of the individual dog to maintain a sufficient degree of compensation. Failure of vascular compensation was indicated by the spontaneous return of blood from the reservoir to the animal (‘taking-up’). Experience in several hundred experiments had demonstrated that when 40 per cent of the maximum bleeding volume had been ‘taken-up,’ rapid reinfusion of the remainder via a femoral vein would be followed by only a temporary pressor response with subsequent relapse and death in some 90 per cent of dogs. The average duration of the period preceding replacement transfusion was 4 to 4.5 hours. If 40 per cent taking-up had not occurred within 8 hours at arterial pressure 30 mm. Hg, the controlled hypotension period was electively terminated by the reinfusion of the remainder of the shed blood. No therapy was given after blood replacement. The relapse into shock was followed by death within an average of 6 hours; occasionally not until 18 to 24 hours, rarely longer. A number of surviving dogs were killed 48 hours later to obtain bacteriologic and pathologic data. The untreated (‘control’) series (group 1) includes