Abstract
Abstract
Background:
Infection control is a critical aspect in the continuum of surgical care. Much of what is outlined in the literature pertains to hospital-based practice, with only recent attention paid to the more austere environments, particularly those faced during humanitarian or combat operations.
Objective:
This manuscript provides a brief historical review of the development of infection control practices and further identifies and outlines several aspects necessary to successful program applications in austere environments.
Results:
Hand hygiene remains the simplest form of infection control. Use of alcohol-based hand sanitizer is a logistically reasonable option for most circumstances, mitigating the requirement for clean running water to facilitate more traditional “soap and water” methods of hand disinfection. Environmental decontamination, patient cohorting, and patient isolation based on existing colonization/infection also has demonstrated efficacy in controlling cross-contamination and is feasible in most austere environments. Finally, senior leadership engagement with deliberate planning, antimicrobial stewardship, and vigorous quality and process improvement algorithms have resulted in reduced rates of critical infections in these settings.
Conclusions:
Basic tenets of infection control can be achieved even in resource-poor environments. Meticulous attention to adhering to these principles, with support from senior medical and operational leadership, facilitates improvements in infection control outcomes. There remains, however, a need for additional robust outcomes data regarding best practices in these environments.
I
During the late 19th and early 20th Centuries, key modalities of infection control have come from specific patient treatment interventions. Early debridement of devitalized tissues removed a potential medium for encouraging micro-organism growth [2,3]. Moreover, improvements in understanding of the physiologic foundations of shock as well as the importance of restoring tissue perfusion with adequate volume restoration were key facets of minimizing patient-specific risks for the development of surgical infection [4].
Control of non-patient factors also developed during this time. Work by Koch and others helped to advance the concept now known as “germ theory” [5]. It is from this platform that additional key aspects of infection control have developed. Basic personal and environmental hygiene, location and grouping of patients, and robust oversight and analysis of best practices are critical to having a successful infection control program and are achievable even in more remote or austere locations. This paper describes some of the historical developments in these areas and provides an overview of current practices important to the success of such programs in the austere environment.
Materials and Methods
Review of both historical and current literature pertaining to infection control practices was undertaken, looking specifically at practices in the austere environment. Common concepts were then collated and summarized.
Results
Hand hygiene and environmental decontamination are simple and effective means of infection control. Semmelweis, in the 19th Century, observed a difference in infectious morbidity in obstetrical patients from two clinics. He hypothesized that a difference in hand hygiene permitted transmission of an infectious agent from physicians to delivering mothers. After implementing a program to improve hand decontamination systematically, maternal mortality rates declined markedly, providing early evidence that hand hygiene was one basic tenet of infection control [6].
Soap and water have been the mainstay of hand hygiene. However, the austere environment may create a situation in which logistical limitations or overall field conditions (i.e., combat or other hazardous environmental factors) may not permit water-based hygiene efforts. Alcohol-containing hand sanitizers have now become a predominant component of field-expedient hand hygiene efforts. According to several reviews, hand rubbing combined with the use of these alcohol-based agents is effective at reducing bacterial contamination [7,8]. Girou et al. demonstrated a significant reduction in bacterial counts (colony-forming units) by 83% versus 58% when comparing hand rubbing/alcohol-based solution with medicated soap [9]. However, hygiene for visible contamination or because of concern about certain organisms, particularly those that survive in spore form, are not suitable circumstances for these simplified hygiene measures [10,11]. In these instances, traditional antimicrobial soap and water with a vigorous mechanical hand rub are more appropriate.
Care of environmental surfaces also has been the focus of attention for austere environments in several major conflicts. Florence Nightingale, during her work with the British Army in the Crimea during the 1850s, helped improve overall sanitation at the Scutari Hospital. With attention to providing clean environments, meticulous personal hygiene, adequate clothing and bedding, and maintaining reasonable (patient) nutrition, Nightingale led an effort to reduce the excessive hospital mortality rate. Her meticulous use of rigorous data collection and statistical analysis helped effect a drop in the hospital mortality rate from 42% in February 1855 to 2% in June 1855 [6]. Similarly, work by the U.S. Sanitary Commission during the American Civil War demonstrated the need for maintaining cleanliness, hygiene, and sanitation of military field hospitals. Implementing a multitude of techniques to control environmental factors, including use of various antiseptic agents, resulted in a precipitous reduction in hospital gangrene cases after major outbreaks between 1862 and 1864 [6,12].
During the late 1800s, following the work of Lister evaluating the use of carbolic acid solutions, studies with various other antiseptic agents demonstrated reduction in the infectious mortality rate in U.S. military hospitals. Furthermore, proper antiseptic decontamination of surgical instruments, often unheard of during the American Civil War, became the focus of attention during the latter 19th Century. By 1891, German surgeon Ernst von Bergmann introduced heat sterilization of surgical instruments, offering another option for maintaining surgical asepsis [12. Although logistical challenges may again plague highly technical solutions, the array of options available to perform field-expedient antisepsis has become healthy.
Classifying equipment into three categories—critical, semi-critical, and non-critical—permits directed attention to specific aspects of asepsis requirements. Critical items, as described by the U.S. Centers for Disease Control and Prevention (CDC), are those that have a high risk for infection if contaminated with a micro-organism, which will enter sterile tissue environments such as the vascular system. Thus, these are items that need high-level decontamination and sterilization utilizing steam, gas, or certain liquid chemical agents [12,13].
Semi-critical items are those that contact mucous membranes or non-intact skin, such as anesthesia and respiratory equipment and certain endoscopes. Although the medical devices should be free of all micro-organisms, a small number of bacterial spores is permissible [12,13]. These items are amenable to high-level disinfection with chemical disinfectants or steam sterilization. However, several of these items require meticulous decontamination of long/narrow lumina, hinges, and irregular surfaces.
Non-critical items are those that typically contact only intact skin but not mucous membranes. These items may include care items such as blood pressure cuffs or crutches and may include environmental surfaces on bedside tables, bed rails, and floors. Low-level disinfectants, following applicable Environmental Protection Agency (EPA) and manufacturer guidelines, are sufficient to provide adequate disinfection [12,13].
Another aspect to controlling infections is the process of grouping or isolating patients. A transmission-based precaution of placing patients with similar infectious agents (such as multi–drug-resistant organisms [12,13]) or similar risk profiles (such as prior hospital admission >72 hours) in the same location within the facility creates a cohort with similar risk factors. This practice ensures minimal transfer of infectious organisms across a facility and maintains contaminated staff and equipment within a single clinical area or ward [12,14–16]. Similarly, patients with certain contagious or easily transmissible infections warrant isolation from other patients to avoid a disease epidemic. Standard precautions, depending on the agent (droplet/contact/airborne) are appropriate, especially in a more austere environment. Although the logistics may be a challenge, simple separation of patients with space (i.e., an empty cot between patients or a separate tent or building), provision of basic personal protective equipment immediately at bed-side, and maintaining physical separation from traffic flow with curtains and other physical barriers should provide reasonable isolation of these patients [12]. Although airborne precautions may be more challenging in the austere environment without sophisticated air-handling systems or pressure-containment systems, more conventional measures involving bed placement in relation to air flow patterns within the facility should be sufficient to mitigate the risks of cross-contamination [14].
The microbial landscape in austere environments also may present a challenge to non-indigenous personnel. Organisms retained in the soil may become part of the standard bacterial microbiome in wounds sustained during combat or humanitarian operations in these locations, although early investigations to characterize the microbial composition of these combat-related wounds demonstrated a predominance of gram-positive (skin) flora without a preponderance of resistant organisms [17,18]. In some cases, however, these microbes establish a propensity for rapid development of resistance in these antibiotic-naïve bacterial populations. More recent investigations from U.S. operations in Afghanistan have demonstrated a propensity for colonization and infection with MDROs such as Acinetobacter and extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae [19]. Further complicating this circumstance is the potential for wide-spread infiltration throughout the system of evacuation from the area of operations, including home station/home country tertiary-care facilities [20].
Local facility practices may include screening cultures to exclude the presence of MDROs [21]. Utilizing these data to identify patients who are “carriers” in these austere environments may be a means to cohort/isolate these subsets of patients appropriately to mitigate further transmission into hospital-acquired infections. In a surveillance study published in 2011, Hospenthal et al. demonstrated a reduction in Acinetobacter colonization rates at key U.S. military medical centers from 21% to 4% between 2005 and 2009 [20]. Not only may these data be important for the patient populations in the facilities specifically, but they also provide support for the view that down-range practices to limit transmission of such micro-organisms are accomplishing the task effectively.
Discussion
Leadership engagement at all levels will make an infection control program a success at any location. This action is imperative in a more resource-constrained environment. Senior operational and medical leadership personnel should facilitate the availability of the necessary personnel and resources to accomplish the basic mission. Having appropriate intermediate-level consultant expertise available to assist with operational concerns will help guide local policy and process activities and can assist with the formulation of specific action plans based on a review of the available data. In a 2006 study assessing the ventilator-associated pneumonia (VAP) rates in a single combat theater hospital, the authors noted a significant reduction in rate of VAP (per 1,000 ventilator days) from 60.6 in May to 9.7 in December following implementation of a vigorous infection control regimen [22]. Other authors have advocated more strategic level processes, such as specific training for deployed care providers, a system-wide surveillance network, meticulous system-wide antimicrobial stewardship guidelines, and dedicated analytical research paradigms, to assist with infectious risk mitigation [12,23,24].
Conclusion
In summary, providing adequate infection control even in the austere environment can be achieved in a manner similar to that used in a more robust, resource-rich location. In addition to the basic tenets of source control and resuscitation, various non-patient factors require attention by dedicated leadership. Sound programs for hand hygiene, device decontamination/sterilization, environmental control, and patient cohorting/isolation, in conjunction with rigorous antibiotic stewardship and quality improvement programs, are vital to the success of an austere infection control paradigm.
Footnotes
Acknowledgements
There are no conflicts or financial interests to disclose.
Author Disclosure Statement
No competing financial interests exist.