Alessia Cusumano

A Survey on the Thermal Conditions Experienced by a Surgical Team

The complex environment of the operating theatre is shared by a group of people having highly different needs: on one side, there is a surgical team whose work may last many hours and, on the other, an anaesthetized patient often subject to liquid infusion. Up to now, little consideration has been given to the different needs of the surgical team who may be affected according to their positions with respect to the scialytic lamp and their particular task. Clothing influences the comfort of the surgical team to a considerable degree: in fact, in some surgery (orthopaedics, neurosurgery and so on), surgeons and assistants must wear paper overalls beneath non-breathable plastic overalls and protective masks and caps; then, if X-rays are needed during surgery, the second surgeon and the assistants must also wear lead overalls and lead thyroid collars and gloves while the anaesthetists and nurses will keep on wearing non-breathable paper overalls. In consequence, the thermal resistance of the clothing of the surgical staff involved in the same surgical operation could be very different. The purpose of the present work is to report investigations carried out at the SS. Annunziata Hospital in Cento (Ferrara, Italy) and present some of the data obtained. The article describes experimental and theoretical research activities, both ongoing and proposed, inherent to the thermo-hygrometric comfort problems of medical personnel. This study falls within a larger research programme, concerning the microbiological, chemical and physical pollution phenomena and the patients hypothermia problems in an operating theatre.

Ventilation Rates and Unsatisfied Percentage from Indoor CO2 Concentration

This work reports the results of a survey carried out on a hall in a historic building in Palermo (Italy) with the aim of assessing the air quality by means of objective measurement of carbon dioxide (CO2) concentration and its subjective evaluation through a questionnaire. The measured values of CO2 concentration were compared with those evaluated using the Meckler equation under steady-state conditions, having verified necessary parameters such as the constancy of the indoor and outdoor CO2 levels and the uniformity of the CO 2 generation rate for all the occupants. The positive correspondence between measured and calculated results allowed us to utilise, under differing circumstances, the values of the natural ventilation rates achieved in steady-state conditions. By using measured and calculated data, an experimental assessment of the relationships between the CO2 concentration levels and the number of occupants and their level of satisfaction was performed. The indoor air quality level in the hall, evaluated by means of the experimental data, was compared with the subjective responses expressed through a specific multiple choice questionnaire handed out to the occupants. A comparison between the calculated ventilation rates and those required by the main American and European standards shows that natural ventilation in the hall is often insufficient according to these standards which have regard for the minimum requirements for air acceptability. In addition, some general observations on the thermal condition of the hall have been drawn from a comparison between microclimate parameters and the subjective opinions provided by the occupants.

A proposed methodology to control body temperature in patients at risk of hypothermia by means of active rewarming systems.

Hypothermia is a common complication in patients undergoing surgery under general anesthesia. It has been noted that, during the first hour of surgery, the patients internal temperature (T core) decreases by 0.5–1.5°C due to the vasodilatory effect of anesthetic gases, which affect the bodys thermoregulatory system by inhibiting vasoconstriction. Thus a continuous check on patient temperature must be carried out. The currently most used methods to avoid hypothermia are based on passive systems (such as blankets reducing body heat loss) and on active ones (thermal blankets, electric or hot-water mattresses, forced hot air, warming lamps, etc.). Within a broader research upon the environmental conditions, pollution, heat stress, and hypothermia risk in operating theatres, the authors set up an experimental investigation by using a warming blanket chosen from several types on sale. Their aim was to identify times and ways the human body reacts to the heat flowing from the blanket and the blankets effect on the average temperature T skin and, as a consequence, on T core temperature of the patient. The here proposed methodology could allow surgeons to fix in advance the thermal power to supply through a warming blanket for reaching, in a prescribed time, the desired body temperature starting from a given state of hypothermia.