Prevention and control of infection in the ICU

Numerical investigation of impinging jet ventilation in ICUs: Is thermal stratification a problem?

Intensive care units (ICUs) are the high incidence sites of hospital-acquired infections, where impinging jet ventilation (IJV) shows great potential. Thermal stratification of IJV and its effect on contaminants distribution were systematically investigated in this study. By changing the setting of heat source or the air change rates, the main driving force of supply airflow can be transformed between thermal buoyancy and inertial force, which can be quantitatively described by the dimensionless buoyant jet length scale (l m ¯ ). For the investigated air change rates, namely 2 ACH to 12 ACH, l m ¯ varies between 0.20 and 2.80. The thermal buoyancy plays a dominant role in the movement of the horizontally exhaled airflow by the infector under low air change rate, where the temperature gradient is up to 2.45 °C/m. The flow center remains close to the breathing zone of the susceptible ahead, resulting into the highest exposure risk (6.6‰ for 10-µm particles). With higher heat flux of four PC monitors (from 0 W to 125.85 W for each monitor), the temperature gradient in ICU rises from 0.22 °C/m to 1.02 °C/m; however, the average normalized concentration of gaseous contaminants in the occupied zone is reduced from 0.81 to 0.37, because their thermal plumes are also able to carry containments around them to the ceiling-level readily. As the air change rate was increased to 8 ACH (l m ¯ = 1.56 ), high momentum weakened the thermal stratification by reducing the temperature gradient to 0.37 °C/m and exhaled flow readily rose above the breathing zone; the intake fraction of susceptible patient located in front of the infector for 10-µm particles reduces to 0.8‰. This study proved the potential application of IJV in ICUs and provides theoretical guidance for its appropriate design.}.

Physiotherapy elastic band disinfection by UV-C irradiation in an intensive care unit

BACKGROUND

The transmission of healthcare-associated pathogens is mainly related to the massive flow of patients with infections in hospitals, presenting surfaces as potential transmission sources of these microorganisms. The physiotherapist who works in the intensive care area has become a specialist in daily routine in critical care with ventilatory support and post-surgical recovery. Furthermore, for this, the instruments are used in the patient's hands and body. Chemicals such as chlorine derivatives, triclosan, chlorhexidine and, 70 % alcohol are currently used to decontaminate surfaces. This study evaluated ultraviolet C (UV-C) irradiation efficiency in the physiotherapy object's disinfection in daily use in the Hospital Intensive Care Unit (ICU).

METHODS

the microbiological quantification carried out using the elastic band during physiotherapy in a cross-sectional study with 21 patients. The methodology compared the cleaning protocol (70 % alcohol) with a new irradiation method in elastic band in the ICU.

RESULTS

The results showed microbial reductions in the elastic band using both 70 % alcohol and UV-C irradiation (254 nm), with 60 s of illumination, totaling a light dose of 0.78 J/cm²; however, the UV-C irradiation showed better results.

CONCLUSION

This study showed that disinfection by UV-C irradiation could be introduced in an intensive care hospital environment for physiotherapeutic conduct.

[Healthcare associated infections and severity of illness index of patients in intensive care units]

This study was aimed at verifying the relationship between the severity illness index and the occurrence of healthcare associated infections. A prospective cohort was conducted in an intensive care unit of a university hospital, between August 2009 and February 2001. The Average Severity Index Score was used to evaluate the severity of illness. Data was collected by active surveillance and processed in SPSS. Univariate analysis was carried out, statistical signficance when p < 0.05 and confidence interval of 95%. The severity illness index was related to the occurrence of healthcare associated infection, as well as the length of stay in the intensive care unit, patient type, use of invasive procedure, antimicrobials, colonization and patient outcome (p < 0.05). The occurrence of infections was also apredictive factor for the occurrence of death (p = 0.000). These findings reinforce the idea that the occurrence of healthcare associate infections is a complex multifactorial chain, with emphasis on the clinical severity of the patient.

Bacterial resistance and mortality in an intensive care unit

The goal was to identify risk factors for healthcare-associated infections by resistant microorganisms and patient mortality in an Intensive Care Unit. A prospective and descriptive epidemiological research was conducted from 2005 till 2008, involving 2300 patients. Descriptive statistics, bivariate and multivariate logistic regression analysis were used. In bivariate analysis, infection caused by resistant microorganism was significantly associated to patients with community-acquired infection (p=0.03; OR=1.79) and colonization by resistant microorganism (p<0.01; OR=14.22). In multivariate analysis, clinical severity (p=0.03; OR=0.25) and colonization by resistant microorganism (p<0.01; OR=21.73) were significant. Mortality was associated to the following risk factors: type of patient, average severity index, besides mechanical ventilation. The relation between resistant microorganisms and death shows the need to monitor adherence to infection control measures so as to improve care quality and mainly survival of critical patients.

Nosocomial Infection in an Intensive Care Unit in a Brazilian University Hospital

This prospective study aimed to determine the nosocomial infection (NI) incidence in an Intensive Care Unit (ICU), its association with clinical characteristics and occurrence sites. It was carried out among 1.886 patients admitted in an ICU of a University Hospital, from August 2005 to January 2008. Data analysis was done using Fisher’s test and Relative Risk (RR). There were 383 NIs (20.3%). The infections were in the urinary tract (n=144; 37.6%), pneumonia (n=98; 25.6%), sepsis (n=58; 15.1%), surgical site (n=54; 14.1%) and others (n=29; 7.7%). Hospitalization average was 19.3 days for patients with NI and 20.2 days for those with colonization by resistant microorganisms. The mortality was 39.5% among patients with NI (RR: 4.4; 3.4-5.6). The NI was associated with patients originated from other units of the institution/emergency unit, more than 4 days of hospitalization, community infection, colonized by resistant microorganisms, using invasive procedures and deaths resulting from NI.