Studies of patients in a laminar air flow unit

The importance of cleanrooms for the treatment of haemato-oncological patients

The main purpose of cleanrooms in health care centres is to prevent hospital infections or leakage of a highly infectious agent (the source of haemorrhagic fevers, SARS, etc.) into the ambient environment and subsequently possibly threatening other individuals. Patients with haematological malignancies or after autologous or allogeneic haematopoietic stem cell transplantation (HSCT) rank among immunosuppressed individuals. Prolonged and deep neutropenia is considered a key risk factor of the occurrence of an exogenous infection. One of the possibilities of preventing an exogenous infection in these patients is to place them in a "cleanroom" for the crucial period of time. Cleanrooms are intensive care units with reverse isolation. The final part of the general article below provides an overview of the technology and types of cleanrooms for immunosuppressed patients in compliance with the current recommendations and technical standards.

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.

The changing face of febrile neutropenia-from monotherapy to moulds to mucositis. Fever and neutropenia: the early years

The importance of neutropenia as a predisposing factor for infection in patients with haematological malignancies was not clearly appreciated until effective therapeutic agents became available. This led to the important advance of administering antibiotics promptly to neutropenic patients when they developed fever, before a diagnosis was established. Although some antibiotics available in the 1960s had activity against many pathogens in vitro, they were ineffective against infections in neutropenic patients. The development of methods to administer white blood cell transfusions along with antibiotics was beneficial to some patients. The development of new antibiotics was of critical importance, such as methicillin for treatment of Staphylococcus aureus and carbenicillin for Pseudomonas aeruginosa. Prevention of infection was attempted, using isolation rooms, air filtration and prophylactic antibiotics. All of these early efforts laid the foundations for the many important current investigations.

Isolation in the allogeneic transplant environment: how protective is it?

Aggressive infection control measures that include isolating patients within protective hospital environments have become a standard practice during allogeneic stem cell transplantation. A wide range of interventions includes the management of ventilation systems, BMT unit construction and cleaning, isolation and barrier precautions, interactions with health-care workers and visitors, skin and oral care, infection surveillance, and the prevention of specific nosocomial and seasonal infections. However, many of these practices have not been definitively proven to provide patients the intended benefit of decreased infection rates or improved survival. Furthermore, each intervention comes with a financial and social cost. With institutional cost containment efforts and recent trials suggesting that patients may be safely cared for in the outpatient environment after allogeneic transplantation, many widely held practices in managing the transplant environment are being reconsidered. With changing practices, transplant teams are encouraged to review local patterns of infections and associated complications and communicate regularly with infection control committees for guidance on the evolution of isolation needs for the immunosuppressed patient.

Home care versus hospital care of patients with hematological malignancies and chemotherapy-induced cytopenia

BACKGROUND

The purpose of this review study is to examine the accumulating evidence of safety of home care, with regard to infection-related morbidity and mortality, for patients with chemotherapy-induced cytopenia, in light of previous studies on the necessity of protective isolation (PI).

PATIENTS AND METHODS

The existing literature on PI, and home care of cytopenic patients after chemotherapy, published in the English language, based on a Medline search, is reviewed.

RESULTS

The studies published so far on home care versus hospital care are all non-randomized studies and confirm that home care of cytopenic patients is safe, in terms of morbidity and mortality due to infections. On the other hand, the majority of studies on the comparison of PI with standard hospital care conclude that an infection-preventive effect of PI exists. The pooled statistics performed confirmed that such an effect of PI exists regarding the occurrence of severe infections, although no benefit to mortality has been shown.

CONCLUSIONS

Regarding home care, only the results of a prospective, randomized study of sufficient power will enable definitive conclusions to be drawn as to whether home care is equally safe as hospital-based care with PI.

Measurement of bacterial and fungal air counts in two bone marrow transplant units

We evaluated air contamination with bacteria and fungi in a transplantation unit, successively housed in two buildings. Bacterial air contamination was least in laminar air flow rooms, and reduced in ultraclean air rooms in comparison with conventional rooms. Similar results were obtained with culture of air for fungi.

Prospective randomized trial of antibiotic prophylaxis in acute leukemia

Patients undergoing initial remission induction chemotherapy for acute leukemia in a protected environment unit were randomly assigned to parenteral antibiotic prophylaxis or oral and parenteral antibiotic prophylaxis. Complete remissions were obtained in 82 percent of the 45 patients receiving oral and parenteral antibiotic prophylaxis and 76 percent of the 41 patients receiving parenteral antibiotic prophylaxis. Approximately 20 percent of the patients in both groups have had a continuous complete remission for more than five years. The episodes of fever of unknown origin and major infection were significantly more common in patients receiving parenteral antibiotic prophylaxis, although the episodes of local infection were similar in both groups. The duration of remission and survival was similar in both groups. Hence, the oral and parenteral antibiotic regimen was more effective for infection prophylaxis, but had no effect on response to antileukemic chemotherapy.

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.

Evaluation of a protective environment in the management of granulocytopenic patients: a comparative study

Fever, clinical infection, bacteriologically documented infection, and death from infection were evaluated in 95 consecutive uninfected patients with severe granulocytopenia (less than 0.5 x 10(6)/liter). Patients were randomly allocated to reverse isolation and prophylactic oral nonabsorbable antibiotics or to open ward care. The microbiologic surveillance of air samples and stool cultures showed reduction of pathogenic organisms in patients treated in protective environment units. There was a statistically significant reduction in the incidence of fever (80% vs. 39.6%; P less than 0.001), clinical infections (55.3% vs. 25%; P less than 0.01), bacteriologically documented infections (53.2% vs. 20.8%; P less than 0.01), and deaths from infections (25.5% vs. 8.3%; P = 0.02) in patients treated in a protective environment as compared with patients treated on the open ward.

Protected environments in cancer chemotherapy: design and function of a large unit

The construction of a new hospital building permitted the design of a new protected environment unit. The design and operating procedures of this unit are described. Microbiological monitoring has been conducted using air sampling, floor sampling, and settling plates. Microbial contamination is substantially lower in the protected environment unit than in comparable locations elsewhere in the hospital.

Treatment of acute leukemia in protected environment units

Thirty evaluable patients with acute leukemia (AL), aged 14 to 48-year-old received remission induction chemotherapy on a protected environment-prophylactic antibiotic program. Twenty-seven (90%) of these patients achieved complete remission and 17 remained in complete remission for 1 to 22 months. Although these patients spent 36% of their time with neutrophil counts less than 100/mm3, they spent only 20% of their time with fever. Major infection was present during only 7% of the days when neutrophil count was less than 100/mm3. No patient died of an infectious complication during remission induction therapy.

Concentrations of nystatin in faeces after oral administration of various doses of nystatin

Nystatin was administered in ten healthy adult volunteers in increasing doses of 3 X 10(6) I U, 6 X 10(6) I U, 9 X 10(6) I U and 12 X 10(6) I U per day, each dose being given for a five-day period. Faecal samples were collected daily for the determination of their concentration of biologically active nystatin. Nystatin concentrations were determined biologically; the sensitivity of this method was less than or equal to 20 mcg/g of faeces. During the four treatment periods with increasing doses, 38%, 31%, 26% and 20% respectively of the faecal samples contained biologically undetectable amounts of nystatin. This means that nystatin is either inactivated or unevenly distributed through the intestinal contents, or both. The practical consequences of this may be that in a significant portion of the colon there is no inhibitory nystatin concentration against Candida albicans, despite treatment with as much as 12 X 10(6) I U of nystatin per day.

Clinical use of reverse isolation in a protected environment

The therapeutic method of reverse isolation in patients using an aseptic environment in the Life Island or Laminar Air Flow Unit apparatus systems is described on the basis of data from the literature and the authors' experience. A historical summary of views on treatment in an aseptic environment is followed by a description of the method of work with the system of reverse isolation, including important technical, operational and other data. The main indications for treatment are given and the authors' experience with the reverse isolation of 36 patients suffering from blood diseases who were treated in this way over the past four years is evaluated. The experience gained confirms data from the literature that reverse isolation is unequivocally successful in reducing the number of infections in immunologically weakened persons. Other aspects have not yet been definitely assessed.

Microbial skin flora of selected cancer patients and hospital personnel

The bacterial flora of the skin from five anatomical sites on 10 leukemia patients, 10 patients with malignant melanoma, and a control group of 10 medical personnel was examined quantitatively and qualitatively. This was done to determine whether malignant disease results in changes in skin flora and to establish carrier rates of gram-negative bacteria on the skin of personnel in hospital environments. Gram-negative bacteria were isolated more frequently (74 isolates from 100 cultures) from the skin of leukemia patients than from either patients with malignant melanoma (8 isolates from 100 cultures) or the medical personnel (9 isolates from 100 cultures). Klebsiella pneumoniae and Pseudomonas aeruginosa were isolated exclusively from leukemia patients. Relative proportions of gram-negative bacteria in total populations were determined. The axilla was the only site with a uniformly high proportion of gram-negative bacteria. From all other sites cultured, gram-negative populations were low (1 to 5 bacteria/cm2 of skin), although a high proportion of gram-negative populations occurred randomly throughout all subject groups. It was concluded that leukemia patients tend to carry gram-negative bacteria on the skin. The factors permitting colonization of skin by gram-negative bacteria are discussed.

Early consolidation chemotherapy for adults with acute leukemia in remission

Three courses of intensive consolidation therapy were administered to 13 patients with acute leukemia after they achieved complete remission. The patients were randomly allocated to receive their therapy in or out of a protected environment unit and with or without antibiotic prophylaxis. The results suggest that the protected-environment-prophylactic-antibiotic program may have protected the patients from infection, although the numbers in each group are too small for meaningful comparison. However, early consolidation therapy was not beneficial, since the duration of remission and survival of these patients was less than that of a group of comparable patients who received only conventional maintenance therapy.

Infections in cancer patients on a protected environment-prophylactic antibiotic program

A total of 102 studies were conducted on 89 patients receiving cancer chemotherapy while on a protected environment-prophylactic antibiotic program. Major infections occurred during 22 studies. The majority of both minor and major infections originated during the first five weeks after the patients entered the protected environment units. The frequency of infectious complications was inversely related to the circulating neutrophil count. The majority of infections were cases of cellulitis, pharyngitis, pneumonia and septicemia. Most of the infections were caused by gram-negative bacilli. The majority of organisms causing infection had persisted in the patients after their entry into the protected environment units despite the use of prophylactic antibiotics.

Oropharyngeal cultures of patients in protected environment units: evaluation of semiquantitative technique during antibiotic prophylaxis

A semiquantitative culture technique was used to monitor the microbial flora of the oropharynx of 30 patients receiving antibiotic prophylaxis in protected environment units. After institution of antibiotic prophylaxis, the median concentration of organisms in the oropharynx fell by 2 logs but gradually increased by 1 log and then remained stable. Neisseria spp., Micrococcus sp., and Streptococci were generally eradicated by the antibiotics but were replaced by Lactobacilli and yeast. Four of nine enteric organisms persisted despite in vitro sensitivity to the antibiotic regimens. Yeast were cultured from the initial specimens of only 17% of the 30 patients, but they were cultured subsequently from specimens of 80% of the 20 patients who remained in protected environment units for at least 8 weeks.

Oral antibiotic prophylaxis in protected environment units: effect of nonabsorbable and absorbable antibiotics on the fecal flora

Eight patients in protected environment units received by the oral route a solution of gentamicin and vancomycin which completely suppressed all 78 strains of bacteria originally present in their stools. However, when the solution was discontinued bacteria were cultured again from the stools of every patient. Twenty-nine of the 42 strains cultured at this time were also cultured from pretreatment specimens. Oral absorbable antibiotics were given to six of these patients, but they eliminated only 10 of the 32 strains cultured from their stools. Seven of the 16 strains which persisted became resistant to the oral absorbable antibiotic. To achieve maximum effect, oral nonabsorbable antibiotic regimens must be continued as long as the patient remains in a protected environment unit.

Microbiological evaluation of protected environments during patient occupancy

Microbiological monitoring has been conducted in two life island (LI) units and two laminar airflow (LAF) rooms while they were occupied by patients undergoing cancer chemotherapy. There were only 5 organisms per 1,000 ft(3) of air sampled in LAF rooms, 31 organisms in LI units, and over 3,000 organisms in regular hospital rooms. None of the floor samples obtained from hospital rooms was sterile, compared to over 70% in LAF rooms. The rate of deposition of organisms onto settling plates was one organism per 4.5 hr in LAF rooms compared to one organism per 0.08 hr in hospital rooms. Potential pathogens were isolated much more frequently from environmental samples obtained from hospital rooms than from LI units or LAF rooms. Two sites of persistent contamination arose in the LAF rooms: the vinyl tile flooring and the water supply system. Over half of the potential pathogens cultured from the protected environment units were cultured initially from the patients who occupied the units.

Prevention of airborne contamination and cross-contamination in germ-free mice by laminar flow

The efficacy of horizontal and vertical laminar flow units (equipped with high-efficiency air filters) in the prevention of cross-contamination between cages and of contamination from outside has been demonstrated. With germ-free mice and using germ-free standard techniques for sterilization and for the transfer of germ-free mice into the cabinets via a standard entry lock, it was found that during an observation period of 2 weeks the animals remain ;negative'. Other experiments were performed with equally good results in cabinets equipped with a hinged flap, closing 95% of the open front side. When the flap was closed the air flow could be reduced accordingly, thus reducing the noise level and the risk of dehydration.Experiments made with germ-free mice in a ;down-flow unit' were also invariably good.In another type of experiment, cages with conventional mice were placed in the cabinets between cages with germ-free animals at varying distances. If all animals were maintained on wire mesh (to minimize the aerosol production of dust) and if the ;conventional' cages were at a distance of 10 cm. from ;germ-free cages' the latter remained bacteria-free during test periods of one week.The use of ;laminar flow isolators' for the isolation of human patients is mentioned.

Laminar airflow protection in bone marrow transplantation

A laminar airflow room was used to provide a low-pathogen environment for a child with lymphopenic immune deficiency transplanted with paternal bone marrow. Comparison of flora from the patient, personnel, and the environment indicated that no colonization with exogenous organisms occurred in the patient during the 45-day period of study. The number of organisms recovered from the laminar airflow room was exceedingly small. Conventional hospital isolation rooms contained more bacteria and fungi than the laminar airflow room, even when strict aseptic procedures were followed in the former. Patients with lymphopenic immune deficiency and agranulocytosis admitted to conventional isolation rooms were colonized with exogenous organisms within 1 week. Each developed infection with these strains, and one patient died. Laminar airflow isolation seems at present the best means to prevent exogenous infection during hospitalization of patients with lymphopenic and other severe immune-deficiency diseases and may be essential when bone marrow transplantation is performed to treat their immunological defect.

Semiquantitative oropharyngeal culture technique

A semiquantitative method for determining the concentration of organisms constituting the normal oropharyngeal flora has been developed. Eleven species of organisms were isolated from the 18 subjects studied. The concentration of organisms in multiple samples, taken at 5-min intervals, was quite similar. The concentration of organisms increased slightly at the end of the day. Obtaining specimens on different days of the week did not appreciably affect the concentration or kinds of organisms. Eating had only a minimal effect on the oropharyngeal flora, but brushing teeth reduced the concentration of organisms substantially. When specimens were obtained 6 months after the initial specimens, the concentration of organisms remained the same but the species of organisms isolated varied considerably. The gargle method was compared to a swab method and proved to be superior. This method of obtaining oropharyngeal culture specimens is reliable and useful as a means of monitoring the normal oropharyngeal flora.