Aluminium release by coated and uncoated fluid-warming devices.

The use of fluid-warming systems is recommended for infusion rates > 500 ml.h-1 to avoid peri-operative hypothermia. Some fluid-warming devices use disposable aluminium-heated plates for heat transfer, but there is no protective coating to separate the fluid from the heated aluminium surface. It is unknown if this could promote release of aluminium into infusion fluids. We investigated a coated (Fluido compact) and an uncoated (enFlow) fluid-warming device using normal saline or balanced electrolyte solution as infusion fluids, pumped through the heated disposables at flow rates of 2, 4 and 8 ml.min-1 for 60 min each. Aluminium concentrations in the fluid samples were analysed using graphite furnace atomic absorption spectrometry. With saline the coated and uncoated devices yielded aluminium concentrations below the level of quantification (< 128 µg.l-1 ). Similarly, balanced electrolyte solution in the coated device yielded aluminium concentrations < 128 µg.l-1 . However, balanced electrolyte solution in the uncoated device yielded aluminium concentrations of up to 6794 (3465-8002 [1868-7421]) µg.l-1 . Repeating this last study at a flow rate of 2 ml.min-1 resulted in quite high aluminium concentrations when the uncoated device was not heated (~1000 µg.l-1 ) and higher concentrations after the device was heated. We conclude that using uncoated aluminium plates in fluid-warming systems can lead to a risk of administering potentially harmful concentrations of aluminium when balanced crystalloid solutions are used. The mechanism is unclear, but heat is in part involved. Coating for aluminium within medical devices in direct contact with infusion fluids should be recommended.

Combating the spread of carbapenemases in Enterobacteriaceae: a battle that infection prevention should not lose.

The emergence of carbapenemases in Enterobacteriaceae has raised global concern among the scientific, medical and public health communities. Both the CDC and the WHO consider carbapenem-resistant Enterobacteriaceae (CRE) to constitute a significant threat that necessitates immediate action. In this article, we review the challenges faced by laboratory workers, infection prevention specialists and clinicians who are confronted with this emerging infection control issue.

[Prewarming. Yesterday's luxury, today's minimum requirement]. / Vorwärmung. Von der Kür zur Pflicht.

Prewarming is a useful and effective measure to reduce perioperative hypothermia. Due to §23(3) of the German Infektionsschutzgesetz (Gesetz zur Verhütung und Bekämpfung von Infektionskrankheiten beim Menschen, Infection Act, act on protection and prevention of infectious diseases in man) and the recommendations of the Hospital Hygiene and Infection Prevention Committee of the Robert Koch Institute, implementation of prewarming is clearly recommended. There are several technically satisfactory and practicable devices available allowing prewarming on the normal hospital ward, in the preoperative holding area or in the induction room of the operating theater (OR) The implementation of prewarming requires additional equipment and training of staff. Using a locally adapted concept for the implementation of prewarming does not lead to inefficiency in the perioperative process. In contrast, the implementation can help to achieve stable arrival times for patients in the OR.

Efficacy of a novel prewarming system in the prevention of perioperative hypothermia. A prospective, randomized, multicenter study.

BACKGROUND: Perioperative hypothermia is a common complication during general anesthesia. Although rewarming of patients before surgery has been used as a preventive measure and some guidelines recommend it, the implementation of prewarming for every surgical patient is cumbersome. Therefore, we sought to determine the efficacy of two novel prewarming methods that could facilitate prewarming in daily practice. METHODS: This was a prospective, randomized, multi-center, controlled study. After IRB approval and informed consent, 90 patients undergoing surgery of 30-120 min duration with general anesthesia were randomly assigned to three groups: 1) standard preoperative insulation (Group A); 2) passive preoperative insulation with a commercial prewarming suit (Group B); 3) active preoperative prewarming with a forced-air warmer connected to a prewarming suit (Group C). All patients received warmed IV fluids and intraoperative forced air warming after induction of anesthesia. Oral temperatures were recorded in the preoperative and postoperative periods. Intraoperative core temperatures were measured with an esophageal probe. RESULTS: Repeated-measures analysis of variance (ANOVA) and post hoc Scheffé's test identified a significantly higher core temperature in the actively prewarmed group (Group C) compared to both passive groups (A, B) at 15, 30, 45, 60, and 75 min (P<0.05) after induction of anesthesia and at the end of surgery. During the first 30 min after admission at PACU, also higher oral temperatures were measured in Group C, compared with both passive insulation groups. CONCLUSION: In our study active prewarming with a forced-air warmer and an insulating prewarming suit achieves significantly higher core temperatures during anesthesia and at the end of surgery and avoids hypothermia at the end of surgery compared to commercial or conventional insulation techniques.

[Efficacy of a novel warming blanket: prospective randomized trial]. / Effektivität einer neuen Wärmedecke: Prospektive randomisierte Studie.

BACKGROUND: Perioperative hypothermia is a common complication of general anesthesia and occurs in up to 50 % of patients during ear, nose and throat (ENT) surgery. In this prospective, randomized controlled study the hypothesis that a new conductive warming blanket (Barrier® EasyWarm®, Mölnlycke Health Care Erkrath, Germany) is better in reducing the incidence of perioperative hypothermia in ENT surgery than insulation with a conventional hospital duvet alone was tested. MATERIALS AND METHODS: After approval of the local ethics committee and written informed consent 80 patients with a planned procedure time between 1 and 3 h were recruited. Anesthesia was induced and maintained using propofol, remifentanil and rocuronium and the core temperature was measured using an esophageal temperature probe. Patients in the study group were warmed at least 30 min prior to induction of anesthesia using the novel warming blanket (Barrier® EasyWarm®) and patients in the control group were insulated with a standard hospital duvet. Data were tested using Fisher's exact test, Student's t-test or the Mann-Whitney U-test as appropriate. Time-dependent changes in core temperature were evaluated using repeated measures analysis of variance (ANOVA) and post hoc Scheffé's test. Results are expressed as mean ± SD or as median and interquartile range (IQR) as appropriate. A p < 0.05 was considered to be statistically significant. RESULTS: The ANOVA did not identify a significantly higher core temperature in the study group at any time point. Furthermore, Fisher's exact test showed no differences in the incidence of intraoperative (12 out of 29 versus 10 out of 32 patients, p = 0.44) or postoperative hypothermia (12 out of 29 versus 9 out of 32 patients, p = 0.30) between the groups. No adverse effects were observed. CONCLUSIONS: In the studied patient group the new conductive warming blanket (Barrier® EasyWarm®) showed no superiority compared to conventional thermal insulation alone.

The role of 'no-touch' automated room disinfection systems in infection prevention and control.

BACKGROUND: Surface contamination in hospitals is involved in the transmission of pathogens in a proportion of healthcare-associated infections. Admission to a room previously occupied by a patient colonized or infected with certain nosocomial pathogens increases the risk of acquisition by subsequent occupants; thus, there is a need to improve terminal disinfection of these patient rooms. Conventional disinfection methods may be limited by reliance on the operator to ensure appropriate selection, formulation, distribution and contact time of the agent. These problems can be reduced by the use of 'no-touch' automated room disinfection (NTD) systems. AIM: To summarize published data related to NTD systems. METHODS: Pubmed searches for relevant articles. FINDINGS: A number of NTD systems have emerged, which remove or reduce reliance on the operator to ensure distribution, contact time and process repeatability, and aim to improve the level of disinfection and thus mitigate the increased risk from the prior room occupant. Available NTD systems include hydrogen peroxide (H(2)O(2)) vapour systems, aerosolized hydrogen peroxide (aHP) and ultraviolet radiation. These systems have important differences in their active agent, delivery mechanism, efficacy, process time and ease of use. Typically, there is a trade-off between time and effectiveness among NTD systems. The choice of NTD system should be influenced by the intended application, the evidence base for effectiveness, practicalities of implementation and cost constraints. CONCLUSION: NTD systems are gaining acceptance as a useful tool for infection prevention and control.

Public reporting of health care-associated infections (HAIs): approach to choosing HAI measures.

OBJECTIVE: To develop a method for selecting health care-associated infection (HAI) measures for public reporting. CONTEXT: HAIs are common, serious, and costly adverse outcomes of medical care that affect 2 million people in the United States annually. Thirty-seven states have introduced or passed legislation requiring public reporting of HAI measures. State legislation varies widely regarding which HAIs to report, how the data are collected and reported, and public availability of results. DESIGN: The Maryland Health Care Commission developed an HAI Technical Advisory Committee (TAC) that consisted of a group of experts in the field of healthcare epidemiology, infection prevention and control (IPC), and public health. This group reviewed public reporting systems in other states, surveyed Maryland hospitals to determine the current state of IPC programs, performed a literature review on HAI measures, and developed six criteria for ranking the measures: impact, improvability, inclusiveness, frequency, functionality, and feasibility. The committee and experts in the field then ranked each of 18 proposed HAI measures. A composite score was determined for each measure. RESULTS: Among outcome measures, the rate of central line-associated bloodstream infections ranked highest, followed by the rate of post-coronary artery bypass grafting surgical-site infections. Among process measures, perioperative antimicrobial prophylaxis, compliance with central-line bundles, compliance with hand hygiene, and healthcare-worker influenza vaccination ranked highest. CONCLUSIONS: Our qualitative criteria facilitated consensus on the HAI TAC and provided a useful framework for public reporting of HAI measures. Validation will be important for such approaches to be supported by the scientific community.

[Nosocomial pneumonia. Prevention and diagnostic]. / Nosokomiale Pneumonie. Prävention und Diagnostik.

Pneumonia occurring more than 48 h after induction of mechanical ventilation is called ventilator-associated pneumonia (VAP). VAP is the most common nosocomial infection in intensive care medicine and is associated with prolonged intensive care and hospital stay and a higher mortality. The main pathomechanism for development of ventilator-associated pneumonia is not so much the mechanical ventilation per se but more the pathogens passing along the tube towards the lungs. Avoidance of tracheal intubation, strict hygienic measures, reduction of oropharyngeal colonization and the avoidance of microaspiration are the most promising prevention strategies. Therapeutic success in treatment of VAP is coupled to an early diagnosis and therapy. Suspicion of pneumonia is based on clinical and radiologic criteria. Biomarkers and microbiological findings are important for follow-up and reevaluation of the suspected diagnosis.

[Preoperative prewarming as a routine measure. First experiences]. / Präoperative Vorwärmung in der klinischen Routine. Erste Erfahrungen.

BACKGROUND: Despite the broad application of intraoperative warming new studies still show a high incidence of perioperative hypothermia. Therefore a prewarming program in the preoperative holding area was started. METHODS: The efficacy of the prewarming program was assessed with an accompanying quality assurance check sheet over a period of 3 months. RESULTS: During the 3 month test period 127 patients were included. The median length from arrival in the holding area to beginning prewarming was 6 min and the average duration of prewarming was 46±38 min. During prewarming the core temperature rose by 0.3±0.4°C to 37.1±0.5°C and decreased to 36.3±0.5°C after induction of anesthesia. At the end of the operation the core temperature was 36.4±0.5°C and 14% of the patients were hypothermic. CONCLUSION: These data allow 2 conclusions: 1. Prewarming in the holding area is possible with a sufficient duration. 2. Prewarming is highly efficient even when performed over a relatively short duration.

Quantitative analysis and molecular fingerprinting of methicillin-resistant Staphylococcus aureus nasal colonization in different patient populations: a prospective, multicenter study.

OBJECTIVES: To better understand the prevalence of methicillin-resistant Staphylococcus aureus (MRSA) colonization or infection in different patient populations, to perform quantitative analysis of MRSA in nasal cultures, and to characterize strains using molecular fingerprinting. DESIGN: Prospective, multicenter study. SETTING: Eleven different inpatient and outpatient healthcare facilities. PARTICIPANTS: MRSA-positive inpatients identified in an active surveillance program; inpatients and outpatients receiving hemodialysis; inpatients and outpatients with human immunodeficiency virus (HIV) infection; patients requiring cardiac surgery; and elderly patients requiring long-term care. METHODS. Nasal swab samples were obtained from January 23, 2006, through July 27, 2007; MRSA strains were quantified and characterized by molecular fingerprinting. RESULTS: A total of 444 nares swab specimens yielded MRSA (geometric mean quantity, 794 CFU per swab; range, 3-15,000,000 CFU per swab). MRSA prevalence was 20% for elderly residents of long-term care facilities (25 of 125 residents), 16% for HIV-infected outpatients (78 of 494 outpatients), 15% for outpatients receiving hemodialysis (31 of 208 outpatients), 14% for inpatients receiving hemodialysis (86 of 623 inpatients), 3% for HIV-infected inpatients (5 of 161 inpatients), and 3% for inpatients requiring cardiac surgery (6 of 199 inpatients). The highest geometric mean quantity of MRSA was for inpatients requiring cardiac surgery (11,500 CFU per swab). An association was found between HIV infection and colonization with the USA300 or USA500 strain of MRSA (P < or = .001). The Brazilian clone was found for the first time in the United States. Pulsed-field gel electrophoresis patterns for 11 isolates were not compatible with known USA types or clones. CONCLUSION: Nasal swab specimens positive for MRSA had a geometric mean quantity of 794 CFU per swab, with great diversity in the quantity of MRSA at this anatomic site. Outpatient populations at high risk for MRSA carriage were elderly residents of long-term care facilities, HIV-infected outpatients, and outpatients receiving hemodialysis.

Determination of serum propofol concentrations by breath analysis using ion mobility spectrometry.

BACKGROUND: We aimed to measure propofol concentrations in exhaled air with an ion mobility spectrometer coupled to a multicapillary column for pre-separation (MCC-IMS). In addition, we aimed to compare the values of these measurements with serum propofol concentrations, as determined by gas chromatography-mass spectrometry (GC-MS). METHODS: Thirteen patients, ASA I or II, undergoing elective ENT surgery were studied. Anaesthesia was induced with propofol 2.1 (0.7) mg kg(-1), rocuronium 0.5 (0.1) mg kg(-1), and remifentanil 0.5 microg kg(-1) min(-1). After tracheal intubation, anaesthesia was maintained with a continuous infusion of propofol 3.9 (1.8) mg kg(-1) h(-1) and remifentanil 0.5 microg kg(-1) min(-1). Simultaneously, a venous blood sample was obtained. Propofol concentrations in serum were determined by GC-MS and compared with the height of the respective propofol signals achieved by MCC-IMS. RESULTS: Twenty-four pairs of samples were obtained. The comparison of propofol concentrations in exhaled air and serum presented a bias of -10.5% and a precision of +/- 12.3%. With these values, the 95% limits of agreement were 14.1% and -35.1%. CONCLUSIONS: MCC-IMS may be a suitable method to determine propofol concentrations in exhaled air, and may be used to predict propofol concentrations in serum.

Comparison of forced-air warming and resistive heating.

BACKGROUND: Perioperative hypothermia is common during anesthesia and surgery and is accompanied by several complications. Forced-air warming is recognized as an effective procedure to prevent hypothermia. The aim of this study was to compare a resistive heating device with a forced-air warming device. METHODS: Prospective randomized trial. SETTING: heat transfer laboratory of a University hospital. PARTICIPANTS: six healthy volunteers. INTERVENTIONS: warming with a forced-air warming device (BairHugger 505 and Upper Body Blanket 522; Arizant Healthcare Inc., Eden Prairie, MN, USA) or a resistive heating device (Geratherm Adult system; Geratherm Medical AG, Geschwenda, Germany). MEASURES: heat transfer was measured with 11 calibrated heat flux transducers on the upper body. Additionally, blanket and skin temperatures were measured. The t-test for matched pairs was used for statistical evaluation. RESULTS: Skin temperature under the covered surface was not statistically different between the two groups (37.3+/-0.2 degrees C in the forced-air warming group and 37.8+/-0.2 degrees C in the resistive heating group). In contrast, blanket temperature (40.3+/-0.6 degrees C vs 38.1+/-0.4 degrees C, P=0.002) and heat transfer (13.2+/-3.6 W vs 7.8+/-1.9 W, P=0.048) were significantly higher in the resistive heating group. CONCLUSION: Heat transfer in the resistive heating system was significantly greater than that of the forced-air warming system.

Healthcare-associated infections: think globally, act locally.

Healthcare-associated infections (HAIs) have been a hot topic for several decades. An understanding of HAIs should be based on an understanding of the organisms that cause infection and determine prevention. Although some improvements in control in hospitals have been recorded, the community setting is now implicated, and the role of microbiology in diagnosis, detection of carriers and strain typing of organisms is evident. As healthcare systems vary widely, prevention strategies must be designed accordingly. Hand hygiene, however, remains applicable in all settings, and the WHO is strongly promoting alcohol-based hand rubs to interrupt transmission. Some countries are only beginning to develop standards, whereas compliance is obligatory in others. Economics and cost factors are common to all countries, and litigation is increasingly a factor in some.

[Perioperative thermal management]. / Perioperatives Wärmemanagement.

Perioperative hypothermia can influence clinical outcome negatively. It triples the incidence of adverse myocardial outcomes, significantly increases perioperative blood loss, significantly augments allogenic transfusion requirements, and increases the incidence of surgical wound infections. The major causes are redistribution of heat from the core of the body to the peripheral tissues and a negative heat balance. Adequate thermal management includes preoperative and intraoperative measures. Preoperative measures, e.g., prewarming, enhance heat content of the peripheral tissues, thereby reducing redistribution of heat from the core to the peripheral tissues after induction of anesthesia. Intraoperative measures are active skin surface warming of a large body surface area with conductive or convective warming systems. Intravenous fluids should be warmed when large volumes of more than 500-1000 ml/h are required. The body surfaces that cannot be actively warmed should be insulated. Airway humidification and conductive warming of the back are less efficient.

[The applicability of the ProSeal laryngeal mask airway for laparotomies]. / Die Anwendbarkeit der ProSeal-Larynxmaske bei Laparotomien.

OBJECTIVE: The ProSeal laryngeal mask airway (PLMA) has some design features, which in contrast to the classic LMA allow separation of the respiration from the gastrointestinal canal, a higher leak pressure and a better position assessment. It can be debated if these instrumental improvements justify the application of the PLMA for elective abdominal surgery in cases without aspiration risk. Insertion of airway instruments and gastric tube with regard to insertion time and difficulties and frequency of side effects were to be compared for the tracheal tube and the PLMA. The pharyngolaryngeal morbidity for both methods was also of interest. It was approached with direct and indirect postoperative interview techniques. METHODS: 65 patients were investigated both at the university hospital and at the hospital Neu-Bethlehem in Goettingen. The surgical intervention was a surgical or gynecological laparotomy. Anaesthesia was performed with a standardized application of propofol, alfentanil and rocuronium. Glycopyrroniumbromide was applied to minimize salivation. A total of 34 patients received the PLMA, 31 were intubated. All of them were provided with a gastric tube. RESULTS: The insertion of the PLMA took 70 seconds (21 - 234) on average, the intubation 57 seconds (35 - 145). Endotracheal intubation was accomplished in a shorter time period, but there was no significant difference in comparison with the PLMA-group (p = 0.1924). Insertion of the PLMA was significantly more difficult than oral intubation (p = 0.0006). The base of the tongue and the dorsal pharyngeal wall, but not the vocal cords or the epiglottis were visible in those cases, where the PLMA could not be positioned at all. Here the tip of the cuff was bended. The time period for positioning of the gastric tube was 38 seconds (15 - 75) in the PLMA- and 57 seconds (22 - 219) in the tracheal tube group. With these results the gastric tube positioning was accomplished in a significantly shorter time period in the PLMA-group (p = 0.0267), but not at a significantly higher level of difficulty for endotracheal intubation (p = 0,6247). In one case there was regurgitation through the drainage tube without aspiration before gastric tube placement. At the direct interview 16 patients in the PLMA-group and 23 of the tube group mentioned postoperative throat symptoms. The most frequent symptom was hoarseness (11 PLMA- and 18 intubated patients). There was no significant difference between PLMA- and tracheal tube application with regard to the total number of patients with pharyngolaryngeal morbidity and the frequency of single symptoms. The same is true for the degree of the symptoms. There was a tendency for a longer prevalence of throat symptoms after intubation, but no significant difference. CONCLUSION: In this investigation the PLMA could be successfully applied for elective laparotomies in cases without the risk of aspiration. Proper patient selection and a deep level of anaesthesia are important. The advantage for patients receiving the PLMA is a smooth recovery without cough, but not so much a reduced amount of pharyngolaryngeal morbidity. From this observation it might be concluded that the invasiveness of the surgical intervention might also influence the tolerance for the airway instrument. The disadvantage in this study was the more difficult insertion of the PLMA compared with the oral intubation. Further studies with a larger number of patients must show if these first results of the "Proseal"-LMA for lararotomies are to be confirmed.

Methicillin-resistant Staphylococcus caprae in a neonatal intensive care unit.

Staphylococcus caprae, a hemolytic coagulase-negative staphylococcus that is infrequently associated with humans, was initially detected in specimens from six infants in our neonatal intensive care unit due to phenotypic characteristics common to methicillin-resistant Staphylococcus aureus. These isolates were subsequently identified as S. caprae by the Automated RiboPrinter microbial characterization system. This prompted an 8-month retrospective investigation in our neonatal intensive care unit. S. caprae was the cause of 6 of 18 episodes of coagulase-negative staphylococcal bacteremia, was the most common coagulase-negative staphylococcus recovered from the nares of 6 of 32 infants surveyed in a methicillin-resistant S. aureus surveillance program, and was isolated from 1 of 37 health care providers' hands. Of 13 neonatal intensive care unit isolates tested, all were methicillin resistant and positive for the mecA gene. All 21 isolates were found to be a single strain by Automated RiboPrinter and pulsed-field gel electrophoresis with ApaI or SmaI digestion; ApaI was more discriminating in analyzing epidemiologically unrelated strains than Automated RiboPrinter or electrophoresis with SmaI. These findings extend the importance of S. caprae, emphasize its similarities to methicillin-resistant S. aureus, and demonstrate its ability to persist in an intensive care unit setting.

Staphylococcus aureus with reduced susceptibility to vancomycin.

Infections with Staphylococcus aureus with reduced susceptibility to vancomycin continue to be reported, including 2 cases caused by S. aureus isolates with full resistance to vancomycin. This review first outlines the definitions of vancomycin-intermediate S. aureus (VISA) and vancomycin-resistant S. aureus (VRSA) and risk factors for infection. Next, we describe the mechanisms of resistance and methods of laboratory detection of the organisms. Finally, we address infection control and management issues associated with isolation of VISA and VRSA.

[Heat transfer by conductive warming with circulating-water mattresses]. / Wärmetransfer bei konduktiver Wärmung durch Wassermatten.

AIM OF THE STUDY: To determine the heat transfer by circulating-water mattresses placed under the back and over both legs of human volunteers. METHODS: With approval by the local ethics committee and informed consent eight minimally clothed volunteers were included in the study. Six calibrated heat flux transducers were placed on the back and additionally eight sensors were placed on both legs of each volunteer. The volunteers reclined on a circulating-water mattress (ComfortPad Plus(R), Cincinnati Sub-Zero Products Inc., Cincinnati, OH, USA) coated with gel (Granulab International, Armersfoort, Niederlande). Another circulating-water mattress (Plastipad trade mark, Cincinnati Sub-Zero Products Inc.) was placed over both legs. Both devices were heated to 41 degrees C by a hypo-hyperthermia system (Hico-Variotherm 530, Hirtz and Co. Hospitalwerk, Cologne, Germany). Heat flux data were sampled during steady-state conditions. After determination of the contact area between the mattresses and the skin, heat transfer was calculated by multiplication of the heat flux per area by the contact area. RESULTS: Heat flux per area to the back was 45.6 +/- 4.5 W m (- 2), the contact area was 0.39 +/- 0.03 m (2). This resulted in a heat transfer of 18.0 +/- 2.4 W. Heat flux per area to the legs was 24.7 +/- 4.3 W m (- 2), the contact area was 0.12 +/- 0.01 m (2). This resulted in a heat transfer of 2.9 +/- 0.6 W. CONCLUSION: The heat transfer of the circulating-water mattress to the back was much higher than the heat transfer to the legs. Nevertheless, model calculations show that conductive warming of the legs is more important for the prevention of perioperative hypothermia than conductive warming of the back, because it has a higher impact on the heat balance.