Proteolytic enzymes as adjuncts to antibiotic prophylaxis of surgical wounds

The success of antibiotic treatment of contaminated open wounds is related to the time at which the antibiotic is administered. In standardized guinea pig wounds contaminated with 10⁶S aureus, immediate treatment with topical benzyl penicillin prevents the development of infection. When this same treatment is delayed three hours, all wounds become infected. It is our belief that the fibrinous exudate present in open wounds prevents the antibiotic from gaining access to the sites of bacterial contamination and limits the therapeutic benefits of delayed antibiotic therapy.Enzymatic hydrolysis of the wound coagulum with the proteolytic enzyme trypsin significantly enhances the therapeutic value of antibiotics in the delayed treatment of contaminated wounds. On the basis of these experimental studies, a regimen has been established for the use of proteolytic enzymes as an adjunct to delayed antibiotic treatment of contaminated wounds. When treatment is delayed three hours, the optimal dose of trypsin is 25,000 NF units per wound. The effectiveness of trypsin is enhanced by prolonging its application time; contact of the enzyme with the wound for thirty minutes prevents the development of infection and limits bacterial growth. The effectiveness of the enzyme is increased by repeating the applications. The route by which the antibiotic is administered does not affect the value of proteolytic enzymes; proteolytic enzymes enhance the therapeutic value of both topical and systemic antibiotics.     

Mechanical cleansing of contaminated wounds with a surfactant

Mechanical cleansing of a wound with a sponge soaked in a surfactant has prevented the development of experimental wound infection. The surfactant utilized for wound cleansing is Pluronic F-68, a member of a family of block copolymers called Pluronic polyols. Long-term toxicity studies and clinical trials suggest that this surfactant is safe for human use. Pluronic F-68 is a nonionic detergent that does not have any intrinsic antibacterial activity.Although mechanical cleansing with salinesoaked sponges effectively removes bacteria, it damages the wound and impairs its resistance to infection. The severity of the damage to the skin exerted by the sponge can be correlated with its porosity. Sponges with a low porosity are abrasive and exert more damage to skin than do sponges with a higher porosity. The addition of Pluronic F-68 to even the most abrasive sponges ensures that the bacterial removal efficiency of the sponge scrub is maintained, while tissue trauma is minimized. This dual effect of the surfactant results in a dramatic reduction in the infection rate of contaminated wounds. On the basis of these results, a clinical trial with surfactant-soaked sponges would appear to be indicated.     

Activity of antibiotics in contaminated wounds containing clay soil.

Most traumatic wounds are contaminated to some degree by soil and run a high risk of infection. The presence of soil in wounds interferes with natural tissue defenses, which include phagocytosis and serum bactericidal capacity. The experimental studies reported herein clearly demonstrate that soil also limits the antibacterial effects of specific antibiotics. This inactivation appears to be the result of a chemical reaction between the charged antibiotics and the soil particles.     

Studies in the management of the contaminated wound. IX. Quantitation of the Evans blue dye content of open and primarily closed surgical wounds

The purpose of the present study was to quantitate the changes in the vascular permeability of open and primarily closed wounds after bacterial contamination. Alterations in vascular permeability in tissue were indicated by measuring the content of Evans blue dye in open and primarily closed wounds at different intervals after wounding and contamination. Evans blue dye forms a stable complex with circulating plasma albumin and extravasates through the walls of vessels as they become increasingly permeable.One hour after wounding, the tissue in the clean open wound exhibited a marked increase in dye content when compared with primarily closed wounds not subjected to bacterial contamination. The elevated dye content in the open wound persisted at least seventy-two hours after wounding. Contamination of the open wound with Staph aureus resulted in minimal changes in the content of dye when compared with open wounds not subjected to contamination. In contrast, topical application of Staph aureus to the surface of a wound undergoing primary closure elicited a marked increase in the Evans blue dye content of the primarily closed wound.It is postulated that the increase in Evans blue dye in the clean open wound is a reflection of extravasation into the wound of plasma proteins that form a serous exudate. This accumulation of blood proteins in the open wound may account for its resistance to infection by providing either local lymphatic blockades to bacterial invasion, wound drainage for removal of foreign bodies, antibacterial activity that renders the wound free of bacteria, or all of these factors.     

Mechanical performance of surgical sutures.

A comprehensive analysis of the mechanical performance of sutures has been made to provide information concerning the reliability and security of knotted sutures. The tests utilized in this analysis were designed to be easily reproduced by other investigators. The construction of the knot and the knot performance analysis were undertaken utilizing an Instron Tensile Tester. The mechanical reliability of each knotted suture was determined by measuring the number of throws to reach knot break, the expected slippage of the knot when it reaches knot break, and the maximal holding force at knot break. On the basis of these measurements, recommendations are made for the use of a suture at operation.     

Biology of infections of split thickness skin grafts

The purpose of this study was to identify determinants of split thickness skin graft infection. The bacterial count of the experimental wounds was proportional to the incidence of infection in split thickness skin grafts. When the wound was heavily contaminated with 10⁷ organisms, infection developed under most grafts. Graft take frequently occurred in wounds subjected to a lower level of inoculum. The importance of bacterial counts as a determinant of potential skin graft infection was also suggested by a clinical study. We now routinely use quantitative bacterial counts to identify the granulating wounds that are ready for grafting. The type of organism played no significant role in the development of infection.The recipient site on which the graft was placed had an important bearing on infection of split thickness skin grafts. The incidence of skin graft infection was higher in fascial wounds than in dermal wounds contaminated with the same level of inoculum. Meshing of the split thickness skin graft offered no significant protection against infection. The infection rates of meshed and nonmeshed grafts did not differ significantly in experimental and clinical wounds.     

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 equilibrium 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.     

A new filtered sump tube for wound drainage

A new filtered sump tube has been designed for drainage of collections of fluids from wounds without the danger of infection by airborne contaminants. A two-staged filter has been attached to the vent lumen that removes particulate matter and bacteria from the air that passes through the filter. A clinical evaluation of this tube confirms the superiority of sump drainage as compared with closed suction drainage in the removal of fluids from wounds or cavities.     

Debridement: An essential component of traumatic wound care

The harmful influences of devitalized tissue on wound defenses are documented and the importance of wound debridement in the care of the traumatic wound is stressed. All devitalized soft tissues damaged the host's defenses and encouraged the development of infection. The capacity of devitalized muscle, fat, and skin to enhance infection was comparable. The infection-potentiating effect of skin was enhanced by exposing it to a dry thermal injury. The mechanisms by which devitalized soft tissue enhanced infection are several. The devitalized soft tissue acts as a culture medium promoting bacterial growth. In addition, the devitalized tissue inhibits leukocyte phagocytosis of bacteria and subsequent kill. Finally, the anaerobic environment within the devitalized tissue may also limit leukocyte function.     

Airless paint gun injuries: Definition and management

A standardized model has been developed to provide insight into the definition and management of airless paint gun injuries. With this model, the structure of paint materials has been correlated with their toxicity. Soya alkyd, a paint vehicle, elicited a greater inflammatory response than did any other material. The solvents mineral spirits, xylol, and turpentine were less destructive to tissue than was soya alkyd, followed by the vehicle acrylic latex and the pigment titanium dioxide. The ability of paint components to potentiate infection was studied by injecting them into tissues contaminated with S aureus. Acrylic latex and titanium dioxide were the only components of paint that potentiated infection.Once a component of paint was injected into tissues, it was extremely difficult to remove. Incision and drainage of the paint injury did not remove enough foreign material to minimize its deleterious effects. Supplemental irrigation of the incised paint injury was of no demonstrable value.Antibiotics appear to have an important place in the care of a patient with a paint injury. Antibiotics markedly reduced the number of bacteria in contaminated paint injuries and minimized the destructive effects.Treatment of the animals with steroids shortly after the paint injury limited the severity of the inflammatory response to certain components of paint.The difficulties encountered in treating paint injuries confirm the necessity for safety regulations and standards for all high pressure injection devices and the need for use and development of the least toxic paint materials.     

Surgical floatation retention button

A surgical floatation button has been designed that protects the underlying skin from excessive pressure exerted by a retention suture. The floatation button consists of an outer rigid disc inset in a circular microcell sponge. The button uniformly distributes pressure to underlying skin, eliminating the skin necrosis that is commonly encountered after the use of rigid buttons.     

Identification of the wound infection-potentiating factors in soil

Even the most trivial combat wound is regularly contaminated with soil. Unless this foreign body is adequately cleansed from the wound the risk of subsequent infection is great. The causal factors for this deleterious effect of soil have, until now, been unknown. Results of this study have led to the identification of the factors in soil that potentiate the development of infection.When an injury contained as few as 100 bacteria, the addition of 5 mg of soil led to infection. When this soil sample was fractionated, it was found that the infection-potentiating factors (IPFs) resided predominantly in the clay or organic soil fractions or both. The type of cation adsorbed by the surface of the IPF did not influence its toxic effects on tissues. Silicate clay fractions contain several colloidal clay minerals: montmorillonite, illite, and kaolinite. Montmorillonite clay enhanced the development of infection more than did illite or kaolinite.The IPFs in organic and clay fractions of soil can be characterized by their large surface area and high cation exchange capacity. This physical property of the IPFs ensures an active chemical exchange between the wound and the IPFs which may account for their deleterious effects. Isolation and identification of the factors in soil that potentiate infection will enable us to develop technics for the efficient removal of these agents based on modern pedologic methods.     

Platysma myocutaneous flap for intraoral reconstruction.

Fourteen patients were treated for intraoral epidermoid carcinoma with a single stage reconstructive technic employing a myocutaneous flap based upon the platysma muscle. This flap carries on its distal tip a portion of isolated cervical skin to be used for intraoral replacement of the resected tissue. The flap has proved to be highly reliable and has significant benefits over many other technics commonly employed for head and neck reconstruction.     

Inadequacy of steroids in the treatment of severe hemorrhagic shock.

Massive doses of methylprednisolone were given to dogs prior to severe, lethal, hemorrhagic shock. An untreated group of dogs subjected to hemorrhagic shock served as controls. No persistent significant differences were seen in cardiac output, mean arterial blood pressure, superior mesenteric artery flow, and survival. Calculated total peripheral resistance tended to be lower in the treated dogs and was significantly lower after reinfusion of shed blood. Pretreatment with methylprednisolone did not prevent plasma elevations of the lysosomal enzymes, cathepsin D and beta-glucuronidase. Stabilization of hepatic lysosomes in treated dogs subjected to hemorrhagic shock was not evident. The results failed to indicate significant salutary effects of methylprednisolone sodium succinate in this lethal hemorrhagic shock model.     

Surgical management of epidermoid carcinoma of the anus.

An analysis of twenty-six cases of epidermoid carcinoma of the anus from the University of Virginia Medical Center and 1,060 cases from the usrgical literature has been presented. We believe this review justifies the following conclusions. (1) Considerable delay in diagnosis frequently occurs, adversely affecting the prognosis of patients with this disease. (2) Abdominoperineal resection remains the treatment of choice. Wide local excision is inadequate for most lesions, and should be reserved for lesions of the anal verge less than 2 cm in diameter with favorable histology, that is, low grade of malignancy. (3) Large lesions and those with a high grade of malignancy are associated with a poor prognosis, but even these patients may sometimes be cured with aggressive surgical excision. (4) Synchronous inguinal node metastases are associated with a poor prognosis, but an occasional patient may be cured by iliofemoral node dissection. (5) Iliofemoral node dissection is indicated for metachronous inguinal node metastases in the absence of distant spread. (6) Iliofemoral node dissection should not be performed if these nodes are not clinically involved with metastases. Approximately 70 per cent of these patients will not need this procedure and would therefore have this resection and its attendant morbidity unnecessarily.