Hypothermia, characterized by a reduction in core body temperature, is a prevalent occurrence in the perioperative context and is associated with adverse consequences, including surgical site infections, protracted hospital stays, and heightened mortality rates. Therefore, it is crucial to accurately predict a patient's core temperature during surgery to prevent hypothermia and improve their chances of recovery. The objective of this study was to develop a robust model utilizing numerical heat transfer methods to accurately predict core temperature changes in perioperative patients, applicable to a diverse population with varying heights, weights, and body compositions. This model combines the indirect calorimetry method to calculate the metabolic rate accurately and the equivalent thermal conductivity method to simplify the heat transfer, considering the impact of anesthesia-induced thermoregulatory impairment. The measured environmental data and body temperature distribution data, which include the core temperature, deep wound temperature, and skin surface temperature, from mockup surgeries on animal patients were used to determine the boundary conditions. Data obtained from the monitoring of patients at St. Olavs Hospital were used to validate the model. The results demonstrated that the model could maintain a temperature accuracy of 0.2 degrees C within one hour for patients with varying physical characteristics and provide reliable predictions of overall body temperature distribution. This model holds promise for aiding surgeons in the operating room to accurately determine the risk of hypothermia in patients.

Maintaining acceptable indoor air quality within operating rooms (ORs) in healthcare facilities is vital to prevent surgical site infections (SSIs). Two prevalent ventilation systems, laminar airflow (LAF) and mixing ventilation (MV), are widely used in ORs for various surgical operations. However, several studies have stated that these systems have slightly different SSI rate controls. Earlier studies discovered the airflow velocity above the surgical incision in LAF-equipped ORs to be twice as high as in MV-equipped ones. In addition, the placement of surgical lamps and different airflow patterns add complexity to the study of the surgical microenvironment. The objective of this study is to characterize the airflow pattern in the surgical microenvironment by computational fluid dynamics (CFD) simulations and experimental measurements in the newly built operating room lab at NTNU. The findings may provide new guidelines for standards development ensuring safer surgeries in healthcare facilities. The research project is called: Reduction of postoperative surgical site infection (POSI) through the development of XR tool. The project is supported by the Norwegian Research Council and Norconsult.

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The objective of this study is to explore the effects of different room temperatures and different types of activities on the indoor air quality in the operating room during surgery. Three mock-up surgeries were performed at 21 °C, 23 °C, and 25 °C at St. Olavs hospital in Norway. The effects of the surgeon’s activity and nurse's movement on the concentration of particulate matter at the surgical site and instrument table were compared. The results show that the concentrations of particles at both the surgical site and the instrument table are the lowest at room temperature of 23 °C. The activity of the surgeon was the main factor leading to the increase in the concentration of particulate matter with the size 0.3-0.5 μm at the surgical site, while the nurse movement led to the increase in the concentration of particulate matter with the larger size. At all room temperatures, the movement of the distribution nurse had a greater effect than the activity of the surgeon on the increase of the concentration of particles at the instrument table. In addition, the intensity of the particulate source may be factors affecting the concentration of particulate matter. Therefore, it is recommended that distribution nurses should avoid unnecessary activities during the operation.

This experimental study analysis the low mass flux of refrigerant R134a, R404A, and R407C in the smooth vertical evaporator tube with an inner diameter of 32 mm. This downward-flow refrigerant with a mass flux of about 9 kg.m(-2).s(-1) in the parallel/counter flow of heating water shows suppressed heat trans-fer by convective boiling and dominant heat transfer by nucleate boiling. This dominant heat transfer by nucleate boiling is dependent on the superheated wall of evaporator tube. The experimentally obtained Nusselt number correlates 92.2 % for R134a, 92.4 % for R404A, and 83.2 % for R407C with the predicted Nusselt number for mass flux over 10 kg.m(-2).s(-1). In summary, the untypically low mass flux of refrig-erant about 9 kg.m(-2).s(-1) is comparable with the current state of knowledge for low mass flux over 10 kg.m(-2).s(-1). (C) 2021 Elsevier Ltd. All rights reserved.

Without confirmation of the ventilation design conditions (typology and airflow rate), the common practice of identifying unidirectional airflow (UDAF) systems as equivalent to ultra-clean air ventilation systems may be misleading, but also any claims about the ineffectiveness of UDAF systems should be doubted. The aim of this review was to assess and compare ventilation system design conditions for which ultra-clean air (mean <10 cfu/m(3)) within 50 cm from the wound has been reported. Six medical databases were systematically searched to identify and select studies reporting intraoperative airborne levels expressed as cfu/m3 close to the wound site, and ventilation system design conditions. Available data on confounding factors such as the number of persons present in the operating room, number of door openings, and clothing material were also included. Predictors for achieving mean airborne bacteria levels within <10 cfu/m(3) were identified using a penalized multivariate logistic regression model. Twelve studies met the eligibility criteria and were included for analysis. UDAF systems considered had significantly higher air volume flows compared with turbulent ventilation (TV) systems considered. Ultra-clean environments were reported in all UDAF-ventilated (N = 7) rooms compared with four of 11 operating rooms equipped with TV. On multivariate analysis, the total number of air exchange rates (P=0.019; odds ratio (OR) 95% confidence interval (CI): 0.66-0.96) and type of clothing material (P=0.031; OR 95% CI: 0.01-0.71) were significantly associated with achieving mean levels of airborne bacteria <10 cfu/m(3). High-volume UDAF systems complying with DIN 1946-4:2008 standards for the airflow rate and ceiling diffuser size unconditionally achieve ultra-clean air close to the wound site. In conclusion, the studied articles demonstrate that high-volume UDAF systems perform as ultra-clean air systems and are superior to TV systems in reducing airborne bacteria levels close to the wound site. (C) 2021 The Author(s). Published by Elsevier Ltd on behalf of The Healthcare Infection Society.

The presented study focuses on the modelling of a Transparent Insulation Material (TIM) incorporated in a facade structure. An experimental prototype of a Transparent Insulation Facade (TIF) with and without a selective absorber was developed as part of the opaque building envelope. Experimental measurements were performed using a climatic chamber test with the aim of verifying theoretical models. A detailed comparative investigation of the thermal performance of both TIFs was conducted using numerical CFD methods. The proper consistency between the simulation results and the experimental data indicated that the simulation model was reliable for predicting the overall thermal performance of TIM based solar facade prototypes.