Introduction: We use Mechanical ventilation (MV) in intensive care units (ICU) for patients requiring partial or complete respiratory support. It provides artificial support for gas exchange. The use of MV implies a good knowledge of the pathophysiology of the disease, constant monitoring of its dynamics, and adjustment of the breathing modality and intensity of respiratory support with the application of measures that reduce the potentially harmful effects of the MV itself. An acute respiratory failure (ARF) is the most typical indication of MV. It is a condition in which the patient's respiratory activity is insufficient or completely absent, and it arises from various respiratory, cardiovascular, or endocrine diseases. In addition to ARF, MV also indicates in patients with prolonged awakening after complex and long-term surgical procedures and in patients with various neurological diseases or disorders of the state of consciousness. Considering that MV is an invasive technique, it carries numerous complications, including lung barotrauma, infections and injuries to the respiratory system, diaphragm atrophy, and cardiovascular complications. The work aimed to compare the frequency of respirator use in the intensive care unit of the Dubrovnik General Hospital during 2019 and 2020. The research assumes (hypothesis) that the age and gender of the patient will not affect the frequency of connection to mechanical ventilation. In contrast, patients with associated chronic diseases will show an increased connection frequency. It had assumed that in 2019 and 2020, before the SARS-CoV-2 virus pandemic, there was no significant change in the number of patients treated with MV in the ICU. Subjects and methods: A retrospective study included patients treated with MV in the Dubrovnik ICU during 2019 and 2020. The participants had divided into two groups. The first group consisted of patients treated with MV in the ICU during 2019 (January 1, 2019, to December 31, 2019), and the second group consisted of patients treated in 2020 (January 1, 2020, to December 31, 2020). By analyzing the medical history (patient medical documentation, nursing documentation, laboratory, and microbiological findings) of these patients, collected data on the underlying disease that caused the need to connect the patient to MV, the length of time spent on MV, the most common complications of MV and the frequency of infections during MV patients. In both observed years, we investigated the frequency of two lifestyle habits of patients treated for MV in the ICU, cigarette smoking and alcohol consumption. Mechanically ventilated patients with SARS-CoV-2 infection during the SARS-CoV-2 pandemic period in 2020 did not participate in the study. The collected data were analyzed separately for each group and compared with each other. There have been using MS Excel for statistical processing, ANDA and t-test. Results of the work: The research included 292 patients located in the ICU of Dubrovnik General hospital in 2019 and 2020. In 2019 and 2020, the most common age of hospitalized patients was from 70 to 89 years. In 2019, the percentage of hospitalized patients with a specific age was 51.35%; in 2020, 43.06%. The share of MV patients out of the total number of patients in the ICU was lower in 2019, i.e., 33.8%, while in 2020, this percentage was 40.1%. In both analyzed years, in the most significant number of patients, the central department was surgery, i.e., in 2019, 81 patients, or 55%, and, in 2020, 75 patients, or 52%. In both groups of respondents, most patients were on MV for 1 to 2 days (2019, 70 patients – 47%, 2020, 82 patients – 57%). In both experimental groups, more MV patients were without MV complications compared to those with difficulties (in 2019, there were 93 patients without complications - 62.80%, and in 2020 there were 118 patients without complications - 81.90%). Among the patients who had difficulties in 2019 and 2020, most had VAP, i.e., MV-related pneumonia as a complication of MV. The frequency of VAP in 2019 was the highest in patients who came to the ICU from the surgery department (16 patients, 59%). On the other hand, in 2020, VAP mostly recorded patients were those who came to the ICU from the neurology department (7 patients, 51%). There was no difference in the number of patients on MV who were smokers, while in 2019, more patients consumed alcohol compared to 2020. In 2019 and 2020, most hospitalized patients on MV in the ICU had multiple chronic diseases listed in their anamnesis (2019, 116 patients – 78%, 2020, 115 patients – 80%). The frequency of patients' death treated for MV in the ICU was the same in both examined years (2019, 27% vs. 2020 (26%). Conclusion: Our research confirmed that the patient's age and gender do not affect the frequency of MV use as part of the patient's therapy. Associated chronic diseases in the patient's anamnesis affect the frequency of use of mechanical ventilation as part of the patient's therapy, i.e., the greater the number of associated chronic diseases in the anamnesis, the greater the frequency of use of mechanical ventilation. There was no significant difference in the number of mechanically ventilated patients from the total number of hospitalized patients from the total number of hospitalized patients in the intensive care unit of Dubrovnik General hospital during 2019 and 2020.