**4. Discussion**

In this study, the results of a fully functioning and fully developed telemedicine program comprising four different services, Teledermatology, Teleulcers, Teleeyelids and Teleaudiometries, have been analyzed in terms of journeys to hospitals prevented, time saved, reductions in fuel consumption and reductions in the emission of pollutant and greenhouse gases. The rural and dispersed nature of the area involved increases the effectiveness of telemedicine. The three counties featured in the study have a total population of 228,622, with 66.65% living in rural areas, with an urban area defined as having a population greater than 20,000. From the patient's point of view, they avoid an unnecessary journey to hospital, save on the journey time and reduce their fuel consumption while receiving the same standard of care. From the environmental point of view, there is a reduction in the emission of pollutants and greenhouse gases.

The results are consistent with those from 2016 [6], involving the same geographical area, and relating specifically to the Teledermatology service. Of a total of 5606 consultations, 80.3% were dealt with telematically, while the remaining 19.7% were referred to a specialist for a face-to-face consultation. In 2016, Teledermatology reduced journeys by a total of 99,368 km. This represented 1928 h of travel time saved. CO2 emissions were reduced by 15.2 tonnes. The study included a cost-saving analysis that concluded that using teledermatology instead of face-to-face dermatology consultations could save up to €11.4 per patient visited. Other studies also sugges<sup>t</sup> that the reduction in visits as a result of telemedicine services and the consequent reduction of pollutant emissions is significant [15,16]. A recent study conducted by the vascular surgery division of the Henry Ford hospital in Detroit between October 2015 and November 2017 [17] analyzed the impact of telemedicine on 87 patients. The results showed that the average reduction in pollutants per consultation was 1118 g of carbon dioxide, 294 g of carbon monoxide, 21.6 g of nitric oxide and 32.3 g of other volatile organic compounds. The average distance saved on a round trip was 50.2 km, with an average duration of 39 min. The total reduction in fuel consumption was 734 L with an associated cost of \$622. This includes \$2.50 for parking. Another study by the University of Kansas Medical Center, involving 132 patients and a total of 257 consultations shows an average saving per journey of \$86.13 [18], while in another study by the University of Kentucky, the distance and time saved per visit as a result of telemedicine was 102 km and 66.8 min, respectively [19].

The present study has certain limitations. A prospective analysis would be able to obtain more detailed and individualized information, including data related to the loss of working hours and salary, the degree of driving-related stress, waiting time and additional costs such as parking. None of these costs are included in the current study. In addition, this study does not take into account factors that increase the cost of telemedicine such as the use of platforms or the need for equipment connected to the internet.

For the purposes of the study, the type of transport used has been taken to be a private vehicle with average emissions. The use of public transport or emissions that deviate from the average (whether due to lower emissions through the use of hybrid or electric cars, or higher emissions through the use of outdated and obsolete cars) have not been taken into account. However, public transport is not always easily available in rural areas.

Future studies ought to look at the monetary value of the pollutants which were not emitted, because telemedicine, in addition to saving on direct costs, can contribute to environmental sustainability.
