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Biomedical subjects

R F Edlich

Publications and source records attributed to R F Edlich.

At least 271 records · Page 15Linked to original sources
PubMed1977

Rapid antibiotic disk sensitivities of burn eschar and infected wounds.

This study was undertaken to develop a more rapid antibiotic sensitivity test of the pathogens in soft tissue infections and burn wound eschar. The proposed rapid antibiotic sensitivity test was performed directly on the clinical specimen rather than on single strains of bacteria isolated from the tissue. By performing the antibiotic sensitivity tests directly on the tissue sample, the physician obtains the test results within seven hours after receiving the specimen rather than 38 to 52 hours later, the time delay encountered with the conventional technique. The modification used did not alter most of the standards advised by the Food and Drug Administration (3), since there was no inclusive change in medium, agar depth or antibiotic sensitivity disk. The changes in the Kirby-Bauer (1) test necessitated by using the clinical specimen did not alter significantly the interpretation of the antibiotic susceptibility. If clinically significant numbers of bacteria, 10(6)-10(9), were present, variations in the inoculum size did not appreciably change the results of the antibiotic susceptibility tests. If the incubation requirement for the standard Kirby-Bauer (1) antibiotic susceptibility test was reduced to seven hours, it also did not significantly limit the accuracy of the test. As expected, the variable most difficult to standardize was the heterogeneous inoculum containing large numbers, 10(7), of different organisms. A zone of inhibition interpreted as sensitive with one organism was occasionally masked by the presence of the confluent growth of an organism in which the zone of inhibition was considered resistant. However, even in this instance, it is possible that mixed culture sensitivities may provide the most valid information in mixed infections, since they more closely simulate the real clinical situation.

Anti-Bacterial Agents↗
PubMed1977

Management of soft tissue injury.

The fate of a surgical wound is held in a delicate balance between the host's resistance to infection and the causal factors of infection. Considerable insight into this relationship between the host and pathogen can be gained from the results of quantitative bacteriologic measurements. Newer rapid slide techniques have been developed which provide the surgeon with this information within 20 minutes. In most soft tissue injuries, the wound bacterial count gives an accurate prediction of subsequent infection. Wounds combining greater than 10(5) bacteria per gram of tissue are destined to develop infection. When the bacterial count is below that level, the wounds will usually heal per primam without infection. This large number of bacteria required to elicit infection reflects the remarkable ability of soft tissues to resist infection. This state of high resistance to infection can be reduced by several factors which include circulatory embarrassment, tissue injury, dead space, and the presence of foreign bodies (dirt, sutures, drains, etc.). When treating soft tissue injuries, the surgeon must employ specific therapeutic modalities that allow the wound to heal per primam without infection. On the basis of experimental studies supported by clinical experience, the following treatment protocol for soft tissue injuries is recommended. Using strict aseptic technique, the wound must be first anesthetized with 1 per cent Xylocaine to permit painless sound cleansing. All wounds should be subjected to high pressure syringe irrigation to remove bacteria, foreign bodies, and blood clots. When necessary, debridement of all devitalized tissue should be performed with a stainless steel scalpel. Many wounds caused by sharp wounding agents contain no foreign bodies and few bacteria and exhibit considerable resistance to infection. In these wounds, primary closure can be initiated after irrigation without the development of infection. Wounds resulting from impact forces have a diminished resistance to infection and are susceptible to infection by low level of bacterial contamination. Immediate antibiotic treatment of patients with impact injuries subjected to meticulous debridement and cleansing will permit a safe primary closure. In wounds contacted by pus or feces, open wound management followed by delayed primary closure is usually indicated. Antimicrobial prophylaxis is also recommended for patients with such wounds. Ideal postoperative care of all traumatic wounds includes a surgical dressing and immobilization and elevation of the site of injury.

Anesthesia, Local↗
PubMed1977

Practical bacteriologic monitoring of the burn victim.

A comprehensive picture of the burn wound microflora is now possible as a result of recent technologic advances. The microflora of the burn wound can be characterized with respect to its number, type, location, and antibiotic sensitivity. These parameters can be measured in sufficient time to influence the decision of the burn surgeon. The microflora of the surface of the burn wound and the burn wound itself are examined separately by different sampling techniques. For the surface microflora, the gauze capillary techniques employed, while incisional biopsies are used to monitor the organisms in the burn wound. After sampling, suspensions of the specimens are created which in turn are subjected to direct microscopic measurement, quantitative culture procedures, and immediate antibiotic sensitivity testing. Histologic examination of the burn wound is performed concomitantly with this bacteriologic examination to determine the depth of bacterial invasion as well as to detect the presence of either mycotic or herpetic infections.

Animals↗
PubMed1977

Inhibition of nonspecific defenses by soil infection potentiating factors.

This study was undertaken to examine the effect of soil infection potentiating factors on the defense system of the tissue. Using an in vitro model, leukocyte phite. This damaging effect on leukocyte function was a result of an interaction between the leukocyte and the clay particles. Montmorillonite also interfered with nonspecific humoral defenses. Exposure of serum to clay rapidly eliminated its bactericidal bodies occurred without any damage to the serum opsonins.

Bacteria↗
PubMed1977

Finite deformation theory for in vivo human skin.

A finite deformation mathematical model of in vivo human skin has been developed for the normal physiological load range. Uniaxial load-deformation measurements were carried out with a non-invasive extensometer and utilized in formulating the model. The in vivo strain energy function was found to be a linear function of the first two strain invariants and a quadratic function of the third strain invariant. Only three independent constants were necessary to specify the strain energy function completely for the upper extremities of human volunteers.

Adult↗
PubMed1977

The role of implant porosity on the development of infection.

The role of implant porosity as a determinant of infection was studied. Standardized porous and nonporous polymethyl methacrylate implants were fabricated for this investigation. In rabbits, the premolded polymethyl methacrylate implants were placed under the paravertebral fascia, just superficial to the paravertebral muscle fascia, before inoculation with a measured number of staphylococci. The polymethyl methacrylate implants did not enhance the infection rate of the contaminated wounds. The presence of pores within the implants did not damage tissue defenses. Polymethyl methacrylate implants did not alter the success of antibiotic treatment. Antibiotics prevented the development of infection in wounds containing 10(6) organisms, even in the presence of an implant. When higher levels of organisms were delivered to the wound, antibiotic treatment had a negligible benefit in the implant and control wounds.

Animals↗
PubMed1977

Practical applications of skin biomechanics.

The biomechanical properties of skin have an important influence on plastic surgical decisions. They aid the surgeon in planning elective incisions, excisions, or scar revisions. They provide insight into the most appropriate method of coverage of skin defects as well as the design of an artificial skin substitute. Skin biomechanics can, in part, be characterized in vivo by either a skin extensiometer or by studying the deformation of skin defects. These methods indicate the magnitude and directional orientation of skin tensions which are dependent partly on the mechanical characteristics of the dermal fibers and partly on the pattern in which they are woven. The tensions to which the skin are subjected can be classified as either static or dynamic in origin. Static skin tensions are the natural tensions existing in skin. The magnitude of static tensions varies between individuals, at different sites in the same person, and in different directions in many sites. The dynamic tensions are caused by a combination of forces which are associated with joint movement, mimetic and other voluntary muscle activity, and gravity. Knowledge of these tensions allows the surgeon to align the operative site in the direction of maximal tension and to approximate the wound with the least amount of tension. As a consequence of this, the scar healing between the cut edges of the wound should be narrow and inconspicuous.

Biomechanical Phenomena↗
PubMed1976

A salvage technic for extruded arteriovenous shunts.

In view of the often prolonged periods of pretransplantation and chronic dialysis, every effort should be made to maintain existing arteriovenous shunts or fistulas and to salvage eroded ones when possible. The transposition of unwounded bipedicle flaps or small regional rotation advancement flaps over exposed cannulas is a surgical technic that can salvage eroded shunts and prevent their extrusion and removal.

Arm↗
PubMed1976

Quantitative microbiology: its application to hand injuries.

Quantitative microbiologic analysis of civilian hand injuries has been accomplished in thirty-four patients. Most traumatic soft tissue injuries exhibited an insignificant level of contamination. The number of bacteria recovered from most of those wounds was comparable to that encountered in clean elective surgical hand cases. We now view most civilian hand wounds as clean wounds carrying a very low risk of infection. Our patients with traumatic hand injuries are considered candidates for immediate reconstruction, which includes vascular, bony, or neural repair as well as immediate implantation of Silastic rods in preparation for subsequent tendon grafting.

Bacteriological Techniques↗
PubMed1976

Emergency tracheostomy.

On rare occasions, emergency tracheostomy is indicated to establish an airway. Using a large bore needle as a guide, tracheal intubation is assured with minimal damage to vital structures in the neck.

Airway Obstruction↗
PubMed1976

Pharmacokinetics of a new skin wound cleanser.

Iodophors are effective germicidal agents that have prolonged antiseptic activity in contaminated wounds. A nontoxic surfactant, Pluronic F-68, has been used to formulate a safe and effective iodophor. The parameters necessary to regulate the activity of the iodophor were studied to develop a potent, yet safe bactericidal solution for use in human subjects. The parameters found to be most important were the pH of the solution and the concentration of sodium iodide. Lowering the pH of iodophors increased their stability and antiseptic activity. The free iodine in iodophor solutions prepared with a low pH is predominantly the highly biocidal diatomic iodine (I2). The concentration of iodide regulated the equilbrium of the dissolved iodine between its free and complexed form. Increasing the concentration of iodide in the iodophor lowered the amount of free iodine in solution and enhanced the concentration of the complexed iodide. It is the level of free iodine in an iodophor that determines its antiseptic activity. Low levels of free iodine yielded iodophors that had a slow bacterial kill rate but a prolonged duration of action. Manipulation of these variables permitted the generation of iodophors that varied considerably in their kill rates of bacteria and their duration of antibacterial activity. Iodophors tested in this study demonstrated a distinct superiority to noncomplexed iodine solutions (tincture and aqueous iodine solutions) as wound and skin cleansers.

Animals↗
PubMed1976

Contiguous cervical and deltopectoral flaps for skin lining and replacement with en bloc resection of cancer of the head and neck.

Contiguous cervical and deltopectoral flaps have several advantages in reconstruction of the head and neck after extirpation of cancer. The cervical skin provides an excellent color match for facial skin, and nonhair-bearing skin is available if lining of the oral cavity is required. The deltopectoral flap provides superior coverage for the carotid artery.

Adult↗
PubMed1976

The crush injury: a high risk wound.

A standardized experimental impact injury model was developed to produce soft tissue trauma that simulated impact injuries to soft tissue overlying the cranium. An aluminum impact instrument was constructed so as to deliver a measured amount of energy to a finite area of soft tissue over a fixed foundation. Impact injury resulted in readily demonstrable changes in the morphology of the tissue and its blood flow. As measured by the distribution of fluorescein dye, the blood flow to the impact site was considerably less than that to unwounded tissue. The magnitude of this reduction in blood flow to the site of injury was proportional to the level of energy absorbed by the tissue. The injury to skin resulting from the impact was restricted primarily to the subcutaneous tissue and panniculus carnosus. Loss of adipose tissue and necrosis of skeletal muscle fibers in these layers were associated with the development of a dense inflammatory infiltrate. The structural damage to the tissue and its reduced perfusion were correlated with the tissue's increased susceptibility to infection by bacteria delivered either by direct infection or as a result of a bacteremia. The magnitude of this damage to the host's defenses is, again, directly related to the amount of energy absorbed per unit area of soft tissue. Antibiotics did suppress the growth of bacteria in these experimental soft tissue impact wounds, even when treatment was delayed eight hours. While the therapeutic efficacy of antibiotics was readily apparent in soft tissue impact wounds, the degree to which they could suppress bacteria in these wounds was less than that encountered in the treated control wounds not subjected to impact.

Adipose Tissue↗
PubMed1976

Cleansing the traumatic wound by high pressure syringe irrigation.

The purpose of this study was to examine the influence of the fluid dynamics of syringe irrigation on the efficacy of wound cleansing and the infection rate of experimental wounds. The pressure experienced by a surface following wound irrigation was directly proportional to the pressure within the syringe and the size of the needle. High pressure syringe irrigation effectively removed bacteria from the surface of the wound. This reduction in the wound bacterial count resulted in a decrease in the infection rate of tissues. Low pressure irrigation with an asepto syringe did not significantly cleanse the wound of its bacterial contaminants and had no demonstrable clinical merit. On the basis of these studies, high pressure syringe irrigation is being employed routinely in our emergency department for the care of traumatic wounds.

Animals↗
PubMed1976

Nine-one-one.

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Emergency Medical Services↗