The contribution of a bacterially isolated environment to the prevention of infection in seriously burned patients

Evolution of Burn Care: Past, Present, and Future

Burn care evolved slowly from primitive treatments depicted in cave drawings 3500 years ago to a vibrant medical specialty which has made remarkable progress over the past 200 years. This evolution involved all areas of burn care including superficial dressings, wound assessment, fluid resuscitation, infection control, pathophysiology, nutritional support, burn surgery, and inhalation injury. Major advances that contributed to current standards of care and improved outcomes are highlighted in this article. New innovations are making possible a future where severe burn injuries will require less morbid interventions for acute care and outcomes will restore patients more closely to their pre-injury condition.

Burn Wound Sepsis

Wound sepsis remains perhaps the most feared sequela in the patient who has suffered major burn injuries and leads to overwhelming mortality among patients with extensive burn wounds. The presence of large areas of devitalized, necrotic tissue, coupled with the profound immunosuppression that usually follows major injury, sets the stage for rapid microbial proliferation in the wound; when microbes invade subjacent, previously vi able tissues, invasive burn wound sepsis is defined. Top ical antimicrobial drugs probably have only a limited effect in preventing wound sepsis, and organisms now frequently emerge that are resistant to the commonly used topical agents. Salient factors in the diagnosis and treatment of invasive wound sepsis are discussed in this review. Prevention of wound sepsis, however, is one of the primary objectives of current burn care. Early burn wound excision and immediate wound closure with autograft or a suitable biologic dressing has emerged as the best means for prevention of generalized wound sepsis.

Effectiveness of Bacteria-Controlled Nursing Units in Preventing Cross-Colonization With Resistant Bacteria in Severely Burned Children

Bacteria-controlled nursing units (BCNUs) are laminar air-flow patient isolation units. The rate of cross-colonization with resistant organisms in 66 critically ill pediatric burn patients with massive open wounds and ventilators housed in BCNUs during 5 years was examined and found to be extremely low (3.2 cases per 1,000 patient-days)

Guidelines for prevention of hospital acquired infections

These guidelines, written for clinicians, contains evidence-based recommendations for the prevention of hospital acquired infections Hospital acquired infections are a major cause of mortality and morbidity and provide challenge to clinicians. Measures of infection control include identifying patients at risk of nosocomial infections, observing hand hygiene, following standard precautions to reduce transmission and strategies to reduce VAP, CR-BSI, CAUTI. Environmental factors and architectural lay out also need to be emphasized upon. Infection prevention in special subsets of patients - burns patients, include identifying sources of organism, identification of organisms, isolation if required, antibiotic prophylaxis to be used selectively, early removal of necrotic tissue, prevention of tetanus, early nutrition and surveillance. Immunodeficient and Transplant recipients are at a higher risk of opportunistic infections. The post tranplant timetable is divided into three time periods for determining risk of infections. Room ventilation, cleaning and decontamination, protective clothing with care regarding food requires special consideration. Monitoring and Surveillance are prioritized depending upon the needs. Designated infection control teams should supervise the process and help in collection and compilation of data. Antibiotic Stewardship Recommendations include constituting a team, close coordination between teams, audit, formulary restriction, de-escalation, optimizing dosing, active use of information technology among other measure. The recommendations in these guidelines are intended to support, and not replace, good clinical judgment. The recommendations are rated by a letter that indicates the strength of the recommendation and a Roman numeral that indicates the quality of evidence supporting the recommendation, so that readers can ascertain how best to apply the recommendations in their practice environments.

Sensory environment on health-related outcomes of hospital patients

BACKGROUND

Hospital environments have recently received renewed interest, with considerable investments into building and renovating healthcare estates. Understanding the effectiveness of environmental interventions is important for resource utilisation and providing quality care.

OBJECTIVES

To assess the effect of hospital environments on adult patient health-related outcomes.

SEARCH METHODS

We searched: the Cochrane Central Register of Controlled Trials (last searched January 2006); MEDLINE (1902 to December 2006); EMBASE (January 1980 to February 2006); 14 other databases covering health, psychology, and the built environment; reference lists; and organisation websites. This review is currently being updated (MEDLINE last search October 2010), see Studies awaiting classification.

SELECTION CRITERIA

Randomised and non-randomised controlled trials, controlled before-and-after studies, and interrupted times series of environmental interventions in adult hospital patients reporting health-related outcomes.

DATA COLLECTION AND ANALYSIS

Two review authors independently undertook data extraction and 'Risk of bias' assessment. We contacted authors to obtain missing information. For continuous variables, we calculated a mean difference (MD) or standardized mean difference (SMD), and 95% confidence intervals (CI) for each study. For dichotomous variables, we calculated a risk ratio (RR) with 95% confidence intervals (95% CI). When appropriate, we used a random-effects model of meta-analysis. Heterogeneity was explored qualitatively and quantitatively based on risk of bias, case mix, hospital visit characteristics, and country of study.

MAIN RESULTS

Overall, 102 studies have been included in this review. Interventions explored were: 'positive distracters', to include aromas (two studies), audiovisual distractions (five studies), decoration (one study), and music (85 studies); interventions to reduce environmental stressors through physical changes, to include air quality (three studies), bedroom type (one study), flooring (two studies), furniture and furnishings (one study), lighting (one study), and temperature (one study); and multifaceted interventions (two studies). We did not find any studies meeting the inclusion criteria to evaluate: art, access to nature for example, through hospital gardens, atriums, flowers, and plants, ceilings, interventions to reduce hospital noise, patient controls, technologies, way-finding aids, or the provision of windows. Overall, it appears that music may improve patient-reported outcomes such as anxiety; however, the benefit for physiological outcomes, and medication consumption has less support. There are few studies to support or refute the implementation of physical changes, and except for air quality, the included studies demonstrated that physical changes to the hospital environment at least did no harm.

AUTHORS' CONCLUSIONS

Music may improve patient-reported outcomes in certain circumstances, so support for this relatively inexpensive intervention may be justified. For some environmental interventions, well designed research studies have yet to take place.

Vancomycin-resistant Enterococcus – A Review From a Singapore Perspective

Introduction: Vancomycin-resistant enterococcus (VRE) can cause serious infections in vulnerable, immunocompromised patients. Materials and Methods: In this article, we summarise current data on epidemiology, detection, treatment and prevention of VRE. Results: VRE was first isolated in Singapore in 1994 and until 2004 was only sporadically encountered in our public hospitals. After 2 outbreaks in 2004 and in 2005, VRE has become established in our healthcare institutions. Multiple studies have shown that VRE spreads mainly via contaminated hands, cloths and portable equipment carried by healthcare workers. Conclusions: Only a comprehensive programme (consisting of active surveillance, isolation of colonised/infected patients, strict adherence to proper infection control practices and anti-microbial stewardship) can limit the spread of these organisms. In addition to monitoring the compliance with traditional infection control measures, new strategies that merit consideration include pre-emptive isolation of patients in high-risk units and molecular techniques for the detection of VRE. Keywords: Antibiotic resistance, Infection control, Outbreaks, Surveillance

Wound fluid bacterial levels exceed tissue bacterial counts in controlled porcine partial-thickness burn infections

In the present study, an established controlled burn wound model was used to test the hypothesis that controlled surface contamination with is capable of generating a noninvasive method for the creation of a reproducible deep tissue burn wound infection. Using a liquid tight-wound chamber in Yorkshire pigs, partial-thickness burns were inoculated with saline-immersed for 24 hours. Noninoculated burns and unwounded skin immersed in normal saline served as controls. Bacterial cultures of wound fluid were performed daily, and tissue biopsies for bacteriological and histological evaluations were performed on days 1, 3, and 5. was only recovered from -inoculated wounds (tissue and fluid), whereas all controls contained endogenous only. The number of colony-forming units per gram of wound tissue did not correlate with the bacterial counts found in the overlying wound fluid for any wounds. Fluid counts were consistently higher than tissue counts by two logs. -inoculated wounds showed three times deeper tissue destruction than control wounds. Obtaining consistently deep tissue colonization without cross-contamination among wounds, this study introduces a noninvasive model for controlled burn wound infection suitable for future investigations regarding the efficacy of topical antibiotic wound treatment in experimental burns.

The effect of burn nursing units on burn wound infections

Temporary closure of our burn unit allowed evaluation of the effect of a closed unit on infection rates. During renovations, burned patients were treated either in private ward rooms or in the intensive care unit by burn unit nursing staff using the same wound care practices as used in the burn unit. Data regarding burn severity and outcome were collected and compared for all patients treated before (Group A), during (Group B), and after (Group C) renovations. Burned surface area, average age, and hospital stay were statistically similar for each group. Incidence of infection differed significantly (P < 0.005) with 47% of Group B developing infection compared with 11 and 23% for Groups A and C respectively. Mortality rates were not significantly different. Despite consistent wound care the incidence of infection increased nearly two-fold to four-fold when patients were treated out of the unit. We recommend a temporary isolation unit during renovations if possible.

Nosocomial Pneumonia is Not Prevented by Protective Contact Isolation in the Surgical Intensive Care Unit

Nosocomial pneumonia (NP) is the leading cause of death from hospital-acquired infection in intubated surgical intensive care unit (SICU) patients. To determine whether protective contact isolation would lower the incidence of NP in intubated patients we performed a prospective, randomized, and controlled study in two SICUs in a tertiary medical center. Over a period of 15 months two identical ten-bed SICUs alternated for 3-month periods between protective contact isolation (isolation group) and standard “universal precautions” (control group). In the isolation group all personnel and visitors donned disposable gowns and nonsterile gloves before entering an intubated patient's room; handwashing was required before entry and on leaving the room. In the control group caregivers utilized only “standard precautions” including handwashing and nonsterile gloves for intubated patients. Respiratory cultures were obtained 48 hours after SICU admission and every 48 hours thereafter until extubation, transfer to floor care, or death. Airway colonization (AC) occurred in 72.7 per cent of isolated patients and 69.0 per cent of control patients ( P = 0.61). The incidence of NP was significantly higher in the isolation group (36.4%) compared with the control group (19.5%) ( P = 0.02). There was no statistically significant difference between groups in days from SICU admission to AC, days to NP, and mortality. We conclude that protective contact isolation with gowns, gloves, and handwashing is not superior to gloves and handwashing alone in the prevention of AC and NP in SICU patients and may in fact be detrimental.

Effective control of methicillin-resistant Staphylococcus aureus in a burn unit

Methicillin-resistant Staph, aureus (MRSA) colonization and infection was studied in 231 patients who were admitted to our burn unit and remained for 3 days or more between 1986 and 1994 (patients with inhalation injury only and no burn wound were excluded). The study was divided into two periods: from 1988 to 1989 and from 1990 to 1994. MRSA was found in 80 patients. They increased from 1986 to 1988, slightly decreasing thereafter. In 1994 the incidence of MRSA was 4.3 per cent. The number of strains of MRSA isolated from burn wounds was significantly reduced in the later period. Comparing the two periods, isolation of patients from MRSA, prevention of contamination during care, and reduction in the number of patients initially given second- or third-generation cephem antibiotics were performed more strictly in the later period. The effectiveness of these measures was confirmed. Moreover, the first operation was carried out significantly earlier in the later period. Early excision and early closure of the wound was more effective in preventing and controlling MRSA colonization and infection.

Survival and therapy of burn patients at the threshold of the twenty-first century: a review

This review summarizes the progress achieved in care of burned patients over the last half century by analyzing the most significant results published between 1949 and 1995. Improved survival has paralleled the development of new antibiotics as well as major advances in resuscitation, nutritional support, immunomodulating agents, surgical techniques and wound care. Today the average burn size associated with a 50% mortality breakpoint is about 70% of the total body surface area--a notable increase over figures from the past.

Influence of a changed care environment on bacterial colonization of burn wounds

This study investigated the influence of a conditioned care environment per se on bacterial colonization of burn wounds. Two cohorts of burn patients were treated in the successive years 1992 and 1993, the first group in a (permanent) purpose-designed unit and the second in wards of traditional 'open' design, during renovation of the unit. Patients who were admitted to the permanent and temporary units numbered 224 and 231 respectively, the groups being similar in features that generally influence the course and outcome of burn injuries. The principles and practice of treatment by the burn care team remained the same in both years. No significant difference in wound colonization rates was found between the two groups. We conclude that while the other known advantages of managing burn patients in purpose-designed units remain valid, a conditioned care environment per se does not influence bacterial colonization rates of burn wounds.

Reduction in Staphylococcus aureus wound colonization using nasal mupirocin and selective decontamination of the digestive tract in extensive burns

Following the introduction in 1988 of a regimen of selective decontamination of the digestive tract (SDD) for extensively injured patients in our burns centre, colonization rates with Gram-negative organisms declined significantly, but colonization with Staphylococcus aureus was unaffected. In an effort to reduce staphylococcal colonization, the SDD regimen has been supplemented with intranasal mupirocin since 1991. In this paper, 33 consecutive patients with burns of > 30 per cent TBSA who were treated with the supplemental regimen (SDD + M) in 1991 and 1992, were compared with 34 consecutive patients admitted in the previous 2 years who were treated with SDD only. Staph. aureus colonization of wounds, sputum and gastric aspirates was significantly reduced in the SDD + M group. Gram-negative colonization rates and the incidence of clinical infections remained low in both groups. Our experience suggests that decontamination of endogenous bacterial reservoirs, in combination with isolation measures to prevent exogenous colonization, effectively prevents infectious complications in patients with severe burns.

Effect of chronic interleukin-2 treatment on RES phagocytic activity in the rat

The effect of chronic interleukin-2 (IL-2) injection upon reticuloendothelial system (RES) function in the rat has been determined. Seven-day treatments with two doses of human recombinant IL-2 resulted in a dramatic reduction in the phagocytic uptake of the liver and spleen, while increasing the weight of both organs. There were dramatic histological changes in the intestine, liver and spleen as well. These results suggest that the chronic use of IL-2 can result in hepatic dysfunction, which is associated with altered RES phagocytic function.

Selective intestinal decontamination for prevention of wound colonization in severely burned patients: a retrospective analysis

In this study the effect of selective intestinal decontamination of the digestive tract (SDD) on wound colonization was investigated. Ninety-one patients with at least 25 per cent total burned surface area (TBSA) were included in this study. All patients received oral polymyxin. In 63 patients oral co-trimoxazole and amphotericin B were added to the regimen. The addition of co-trimoxazole decreased the incidence of Enterobacteriaceae wound colonization from 71 per cent to 11 per cent (P less than 0.005). Colonization with Proteus was eliminated in patients treated with co-trimoxazole, compared with an incidence of 36 per cent in the group treated with polymyxin alone (P less than 0.001). The addition of amphotericin B decreased yeast colonization of the burn wound from 39 per cent to 10 per cent (P less than 0.005). A close relation was observed between burn wound colonization and colonization of the gastrointestinal tract. No resistant bacterial strains emerged during the period of study. These results suggest that SDD is an effective method for prevention of wound colonization. Further controlled studies are needed to establish the role of SDD in preventing burn wound colonization and wound sepsis.

The metabolic effects of thermal injury

Major thermal injury is associated with extreme hypermetabolism and catabolism as the principal metabolic manifestations encountered following successful resuscitation from the shock phase of the burn injury. Substrate and hormonal measurements, indirect calorimetry, and nitrogen balance are biochemical metabolic parameters which are useful and more readily available biochemical parameters worthy of serial assessment for the metabolic management of burn patients. However, the application of stable isotopes with gas chromatography/mass spectroscopy and more recently, new immunoassays for growth factors and cytokines has increased our understanding of the metabolic manifestations of severe trauma. The metabolic response to injury in burn patients is biphasic wherein the initial ebb phase is followed by a hypermetabolic and catabolic flow phase of injury. The increased oxygen consumption/metabolic rate is in part fuelled by evaporative heat loss from wounds of trauma victims, but likely also by a direct central effect of inflammation upon the hypothalamus. Although carbohydrates in the form of glucose appear to be an important fuel source following injury, a maximum of 5-6 mg/kg/min only is beneficial. Burn patients have accelerated gluconeogenesis, glucose oxidation, and plasma clearance of glucose. Additionally, considerable futile cycling of carbohydrate intermediates occurs which includes anaerobic lactate metabolism and Cori cycle activity arising from wound metabolism of glucose and other substrates. Similarly, accelerated lipolysis and futile fatty acid cycling occurs following burn injury. However, recent evidence suggests that lipids in the diet of burned and other injured patients serve not only as an energy source, but also as an important immunomodulator of prostaglandin metabolism and other immune responses. Amino acid metabolism in burn patients is characterized by increased oxidation, urea synthesis, and protein breakdown which is prolonged and difficult to reduce with current nutritional therapy. However, the current goal of nutritional support is to optimize protein synthesis. Specific unique requirements may exist for supplemental glutamine and arginine following burn injury but further research is needed before enhanced branched chain amino acids supplements can be recommended for burn patients. Recent research investigations have revealed the importance of enteral feeding to enhance mucosal defense against gut bacteria and endotoxin. Similarly, research has demonstrated that many of the metabolic perturbations of burns and sepsis may be due, at least in part, to inflammatory cytokines. Investigation of their pathogenesis and mechanism of action both at a tissue and a cellular level offer important prospects for improved understanding and therapeutic control of the metabolic disorders of burn patients.

Platelet-activating factor induces intestinal necrosis, but not septic shock, in germ-free and specific-pathogen-free rodents

Platelet-activating factor (PAF) was injected into conventional mice, endotoxin-resistant mice (C3H/HEJ), conventional rats, germ-free rats and specific-pathogen-free (SPF) mice. The PAF resulted in significant necrosis and damage to the small intestines of all the animals tested. In general, the frequency and severity of the lesions were similar in all groups. All the conventional rats and mice, as well as the endotoxin-resistant HEJ mice, were dead 18 h after the injection of the PAF, while all the germ-free rats and the SPF mice survived. These data demonstrate that development of massive intestinal lesions, in the absence of aerobic bacteria, is not sufficient to cause the death of the host from septic shock and endotoxaemia.

Effect of haemolysis on reticuloendothelial system (RES) phagocytic activity in rats

The role of haemolysis of blood in the alterations in the uptake of [99mTc]SC ([99mTc]-sulphur colloid) in vivo in the rat has been examined. When the haemolysed blood (produced by first freezing the blood in liquid nitrogen) was infused into synergenic Lewis rats via the tail vein, there was a significant reduction in the uptake of the [99mTc]SC by the spleen, but lung, liver and kidney uptake remained constant. These results suggest that haemolysis of the blood may play a role in the alterations in RES phagocytic activity observed in the spleen following thermal injury.

Effect of platelet activating factor on reticuloendothelial system function

The effect of platelet activating factor (PAF) injections on the uptake of 99mTc-SC (99mTc-SC (99mTc-sulphur colloid) was determined in vivo. PAF (2 micrograms) injected intravenously into unanaesthetized, unrestrained rats was associated with the development of lesions in the small intestine and alteration of 99mTc-SC uptake in vivo. 99mTc-SC uptake into the lung was increased while spleen uptake was decreased. Pretreatment of the animals with a PAF antagonist, SRI-64-441, prevented the intestinal lesions and alterations of 99mTc-SC uptake. Macrophages, isolated from lung lavage of the PAF-treated rats, demonstrated a decreased generation of hydrogen peroxide in vitro. The present results suggest that, in addition to its other effects on the immune system, PAF can also alter the in vivo phagocytic activity of the reticuloendothelial system in the rat.

Effect of acute burn trauma on reticuloendothelial system phagocytic activity in rats. II: Comparison of uptake of radiolabelled colloid and bacteria

The uptake of radiolabelled colloid or bacteria was compared in normal rats and animals subjected to acute burn trauma. The uptake of colloid by the liver was unaffected by burn trauma, but uptake of the labelled bacteria was reduced. Spleen uptake of both colloid and bacteria was reduced by burn trauma while lung uptake was increased. These data are consistent with the hypothesis that acute burn trauma alters reticuloendothelial system phagocytic activity in the rat towards both inert particles and live bacteria.

Alteration of wound colonization by selective intestinal decontamination in thermally injured mice

The effects of selective intestinal decontamination on the bacterial colonization of burn wounds were investigated in experimentally burned mice. Prior to scalding pathogen-free mice were pretreated with bacitracin to induce intestinal overgrowth of Enterobacteriaceae. Mice treated for 20 days postburn with oral aztreonam had significantly reduced enterobacterial wound colonization compared to untreated controls. This study indicates that burn wound colonization is altered by selective decontamination of the intestinal tract.

Reduction of nosocomial infection during pediatric intensive care by protective isolation

To determine whether simple protective isolation reduces the incidence of nosocomial bacterial and fungal infection during pediatric intensive care, we randomly assigned 70 children who were not immuno-suppressed and who required mechanical ventilatory support and three or more days of intensive care to receive standard care (n = 38) or protective isolation (n = 32) with use of disposable, non-waven, polypropylene gowns and nonsterile latex gloves. Risk factors predisposing patients to infection were comparable in the two groups. Nosocomial colonization occurred later among isolated patients (median, vs. 7 days; P less than 0.01) and was associated with subsequent infection in 12 patients, as compared with 12 patients given standard care (P = 0.01). Among patients who were isolated, the interval before the first infection was significantly longer than (median, 20 vs. 8 days; P = 0.04), the daily infection rate was 2.2 times lower than (95 percent confidence interval, 1.2 to 4.0; P = 0.007), and there were fewer days with fewer (13 percent vs. 21 percent; P = 0.001). The benefit of isolation was most notable after seven days of intensive care. Isolation was well tolerated by patients and their families. Regular monitoring showed that the children in each group were touched and handled comparably often by hospital personnel and family members. We conclude that the use of disposable, high-barrier gowns and gloves for the care of selected, high-risk children who require prolonged intensive care significantly reduces the incidence of nosocomial infection, is well tolerated, and does not compromise the delivery of care.

Survival of an infant with massive thermal injury: a case report

Survival of infants with greater than 80 per cent body surface area burns has not been well documented. Survival of a 4-month-old infant with 80 per cent full skin thickness flame injury is reported. Data from the National Burn Information Exchange showed that there were 2266 infants under 8 months of age treated for burns in reporting hospitals. Only four children of the 2266 were treated for full skin thickness thermal injury covering more than 80 per cent TBSA and none survived except for the child reported here. It was felt that early aggressive excision of the burn eschar was an important factor leading to the survival of this infant. Complex rehabilitation issues related to developmental issues as well as physical and psychosocial needs were identified and addressed throughout her time in hospital by a multidisciplinary team to ensure the best possible quality of life.

Minimizing the potential for nosocomial pneumonia: architectural, engineering, and environmental considerations for the intensive care unit

The development of pneumonia in seriously ill patients remains an important concern of intensive care medicine. The design of the intensive care unit will have a direct effect upon the potential for infection. Persons involved in this design should consider engineering and architectural elements that will ultimately contribute to lower rates of infection. These include components to regulate the atmosphere, such as ventilation systems and temperature and humidity controls. Sources of contaminated water and the amplification mechanisms need to be addressed and minimized in the final designs. Architectural elements such as treatment space and lighting encourage optimal patient management and workable staffing patterns. Personnel who treat seriously ill patients should be part of the planning and design process in the construction and renovation of intensive care facilities.

Emergency treatment of burn injury

Emergency physicians often encounter patients who have suffered burn injuries. Most are minor in nature but approximately 100,000 a year are true emergencies. Regardless of severity, the emergency physician and staff must possess the evaluative skills and knowledge of current treatment regimens to appropriately treat these patients. Burn injuries are classified according to extent of body surface involved and depth of skin injury. This classification, together with an understanding of the pathophysiology based on the source of injury, will allow categorization and thereby determine initial therapy and definitive management. The treatment of minor burns focuses on three primary objectives: relief of pain, prevention of infection and additional trauma, and minimizing of scarring and contracture. With major burns the first hours after injury are characterized by life-threatening problems. Airway injuries, trauma other than the burn injury, treatment of shock, and pain relief are of the highest priority, overriding the management of the burn wound itself. The care that the minor burn victim receives is critical to ultimate outcome; the care that the major burn victim receives is critical to both immediate survival and ultimate outcome. The emergency physician must provide optimal care to ensure optimal results.

Significant reductions in mortality for children with burn injuries through the use of prompt eschar excision

During the past 19 years, mortality due to burn injuries has markedly declined for children at the Boston Unit of the Shriners Burns Institute (SBI), dropping from an average of 9% of SBI admissions during 1968-1970 to an average of 1% during 1981-1986. Detailed statistical analysis using logistic regression was necessary for determining whether this decline in mortality was explained by changes in patient characteristics, such as age or burn size, which are known to strongly influence the outcome of burn injuries. This dramatic decline in mortality during the past 19 years was not the result of change in the age of the patients or their burn sizes; rather, it may be attributed to improvements in burn care. Results of this statistical analysis indicated that, for burn injury patients whose ages ranged from 11 days to 19 years, age had no demonstrable effect on survival from a burn injury. Children survived burn injuries at least as well if not better than the young adult (20-29 years of age). Also, infants (less than 1 year old) survived as well as other children (2-19 years old). Dramatic improvement in survival occurred in patients with burns covering more than 50% of the body surface area. Since 1979, mortality has been essentially eliminated for patients with burn sizes less than 70% of the total body surface area (of 296 patients with burns covering 15-69% of the total body surface area, only two patients died). During the period 1979-1986, 29 of 37 patients (78%) survived an 80% or greater total body surface area thermal injury.

Systemic antibiotic treatment in burned patients

Systemic antibiotics are a valuable therapeutic modality in the burned patient when properly used. Injudicious use, however, may not only fail to be beneficial to the patient but also may produce harmful effects--either through direct toxicity or by contributing to the emergence of resistant strains of micro-organisms. General guidelines and principles for systemic antibiotic use include the following: The burned patient, despite all efforts, will be exposed to microorganisms. No single agent or combination of agents can destroy all the organisms to which the burned patient is exposed. Treatment involves first identifying the organism responsible for clinical sepsis, then choosing appropriate agents. Combinations of antibiotics are not always synergistic or even additive in effect. Multiagent therapy may have the untoward effect of predisposing to superinfection by yeast, fungi, or resistant organisms. Antibiotics should be used for a long enough period to produce an effect, but not long enough to allow for emergence of opportunistic or resistant organisms. Dosages must be adjusted based on serum concentrations when serum assays are available. In general prophylactic systemic antibiotics are indicated in only a few clinical situations including the immediate preoperative and postoperative periods associated with excision and autografting, and possibly in the early phases of burns in children. The penetration of systemic antibiotics into burn eschar remains an area not fully studied; hence, they cannot be the only therapeutic modality used to treat burn wound infection. Systemic dosages of antibiotics in burns will require alteration depending on the clinical status of the patient. The choice of agent requires a thorough knowledge of side effects, toxicity, and potential benefit. Above all, active surveillance and monitoring of the burned patient and the environment in which he or she is being treated is mandatory for effective treatment. The increasing number of new antimicrobial agents has presented a new dilemma to the practicing clinician because many of these agents have not been evaluated thoroughly in the burned population. With further studies, the armamentarium of the burn treatment team will inevitably increase. It is in this manner only that so many of the unanswered questions will be solved, and that infection will start to decline as the major cause of death in the burned population.

Selective intestinal decontamination of the digestive tract for infection prophylaxis in severely burned patients

An oral prophylactic antibiotic regimen aiming at suppression of the gram-negative rods and yeasts of the bowel flora was utilised in 48 severely burned patients to prevent burn wound colonisation. Only 17% of the patients had an actual or potential infection. Only one Pseudomonas infection occurred. The effect of this selective gastro-intestinal decontamination is discussed.

Infections in burn patients

Systemic sepsis resulting from invasive infection remains the leading cause of death among patients hospitalized with major thermal injury. Prevention of infection and death in burn patients requires a thorough knowledge of the multiple predisposing factors involved and expert application of appropriate diagnostic, supportive, and therapeutic modalities. The improved survival in this population is a result of all these factors, not any one. It is this principle and the adherence to a treatment program that encompasses all the modalities which are so essential in the care of burn patients if continuing progress is to be made in this field. This article describes the current management of infection and infection control in burn patients. The burn wound and pulmonary system remain the major foci for infection in this population. Less common types of infection include suppurative thrombophlebitis, suppurative chondritis, bacterial endocarditis, urinary tract sepsis, sinusitis, intra-abdominal sepsis, and infections of the eyes. Prophylaxis protocols involve proper control of the environment and an anticipation of bacterial colonization. A number of specific monitoring and treatment guidelines have evolved that have proved effective over the years in minimizing morbidity and mortality.

Burn therapy 1985: acute management

Mortality occurs from a burn injury because of infections which result from the metabolic and bacterial consequences of a large open wound, depression of the host's resistance, and both protein and total caloric malnutrition. Systemic antibiotics, topical wound therapy, and gentle wound debridement constitute traditional burn therapy. The systemic antibiotics and topical wound therapy do not solve problems presented by large open wounds and the related protein and caloric deprivation. A more rational approach uses antibiotics and topical wound therapy only as adjuncts to a program of early operative removal or excision of the devitalized, burned tissue and immediate closure of the wound. The excised wound is normally closed with available autograft, but in massive burn injuries, donor skin is insufficient. In these massive injuries, artificial skin can provide that immediate wound closure. As long as devitalized, burned tissue remains present in the setting of depressed host resistance, cross infection tends to colonize those remaining devitalized burn wounds with more virulent organisms than those that were already present. Bacterial controlled nursing units (BCNU) provide strict protection against that cross infection. Though inevitably a catabolic response occurs with massive injury, intensive nutritional support provides the calories necessary for the response to injury to avoid a prolongation of that negative nitrogen balance.

Nosocomial infection--the irreducible minimum

Prevalence surveys in different countries have shown that about 1 in 10 hospitalized patients at any one time have acquired an infection and the incidence of infection is usually about 3% to 5%. Can this infection rate be significantly reduced and is there an irreducible minimum below which further reduction cannot be obtained? Cross-infection could probably be almost eliminated by the use of plastic isolators or life islands, and endogenous infections reduced by the wider and more rational prophylactic use of topical and systemic antimicrobial agents, and possibly a range of vaccines. However, the use of these techniques on all patients would clearly be impractical and too expensive for use in the foreseeable future. Excessive isolation techniques would have a detrimental psychological effect on many patients. In addition, failure to eradicate the organisms of the normal flora might be associated with more infections caused by antibiotic-resistant bacteria, fungi and viruses which would be more difficult to treat. Even if organisms could be eradicated, morbidity and mortality might not be correspondingly reduced. Priorities must therefore be set on the most effective use of staff and finances. These not only involve a consideration of infection, but all areas of clinical practice, eg, costs of cardiac transplants and provision of geriatric facilities. It therefore seems likely that little additional finance will be available for control of infection, other than possibly for transmissible infections with high mortality such as AIDS.

Identification and antibiotic susceptibility of bacterial isolates from burned patients

We retrieved bacterial blood isolates from 397 adult burned patients admitted over a 7-year period. Sixty-two patients (15.6 per cent) developed true-positive bacterial blood cultures (judged non-contaminants), and of these 30 (48.4 per cent) expired. Pseudomonas aeruginosa (24 isolates), Staphylococcus aureus (19) and Klebsiella pneumoniae (19) were the most frequent isolates. In vitro susceptibilities of 149 isolates were determined to 12 antibiotics (gentamicin, amikacin, ticarcillin, piperacillin, mezlocillin, azlocillin, cefazolin, cefotaxime, ceftazidime, cefoperazone, thienamycin and ticarcillin-clavulinic acid) using agar diffusion assay. Thienamycin proved the most active agent (97 per cent of isolates susceptible). Cefoperazone was the most active cephalosporin (95 per cent susceptible). Twenty-eight organisms demonstrated multiple drug resistance; patients with such organisms had a 71 per cent mortality. Thienamycin was the most active agent against such isolates (27/28 susceptible). Susceptibilities of all 149 isolates to combinations of antibiotics were calculated, assuming no synergism or antagonism; some combinations of third-generation cephalosporins with the newer penicillins may prove to be as effective as combinations including aminoglycosides.

Delirium in burn patients isolated in a plenum laminar air flow ventilation unit

The incidence of psychological morbidity associated with delirium was compared between burn patients isolated in a bed-size plenum laminar air flow ventilation unit (PLAFVU) and matched control burn patients treated in standard open cubicles. In patients with burn sizes of less than 60 per cent of body surface area, delirium developed in 40 per cent of the patients treated in the PLAFVU, but only in 7 per cent of the matched control patients (P = 0.04). Most of the patients with burn sizes of 60 per cent or greater exhibited delirium regardless of the method of treatment. The development of psychological morbidity was more strongly associated with treatment in the PLAFVU than with common causes such as hyponatraemia or septicaemia. The present study suggests that in the majority of burn patients, i.e. those with less than 60 per cent burns, the development of psychological morbidity may in fact be influenced by types of treatment which affect patient psychology, rather than being solely the result of physiological derangements.

Infections in burned patients

Prevention and treatment of burn wound infection requires knowledge of the epidemiology of such infections. Prevention of infection rests on removal of reservoirs or sources of microorganisms from the burn patient's environment and interruption of transfer of microorganisms to the surface of the wound. When prevention fails and burn wound infection develops, successful therapy may depend on an understanding of the epidemiology of the burn wound during therapy. Contrary to the oft stated concept that antibiotics penetrate the avascular burn wound poorly, our study demonstrated that gentamicin and tobramycin achieved therapeutic concentrations in burn wound tissue. As in other types of infections, susceptible microorganisms were eradicated and resistant microorganisms persisted. Of most importance was the observation that resistant microorganisms may repopulate the wound within four days of starting therapy. It would appear that failure of therapy is not due to failure of antibiotics to penetrate the burn wound but rather to rapid development of superinfection during therapy.

The use of sterile and low microbial diets in ultraisolation environments

The evidence for the use of sterile and low microbial diets in ultraisolation environments is reviewed. Studies have suggested that sterile food is not required for gut sterilization when oral nonabsorbable antibiotics are used, but if a low microbial food contains an antibiotic-resistant organism, colonization can occur. There may be a beneficial effect on the incidence of infection by serving pathogen-free foods, either sterile or low microbial, to the immunosuppressed patient regardless of type of environment, yet the comparative effectiveness of sterile and low microbial diets in preventing introduction of new pathogens accessing the host via the mouth, oropharynx, and esophagus has not been systematically evaluated.

Transient and resident microflora of burn unit personnel and its influence on burn wound sepsis

The exogenous contamination of a thermally injured patient by contact with the health are team has been a major concern of all burn units. Since the University of Chicago Burn Center routinely monitors each burn injury for sepsis by quantitative bacteriology and recently examined the microbial population present on the hands of the health care team, it was felt that these combined data would shed some pertinent information on exogenous burn wound sepsis. Twenty-nine patients with clinical burn wound sepsis and a bacterial level of greater than 10(5) bacteria/gram of tissue were studied. These patients yielded a variety of microorganisms with P. aeruginosa and Staphylococcus aureus being predominant, followed in incidence by Candida albicans. The resident and transient microflora isolated from each member of the health care team treating the specific individual concerned did not correlate with the causative agent of burn wound sepsis. The most frequent isolate from the staff personnel was Staphylococcus epidermidis followed by Micrococcus species. Though colonization of the thermally injured individual has been reported, these data strongly suggest that colonization is primarily one of an endogenous source rather than that of an exogenous one.