Introduction: Respiratory failure, being the reason for admitting a patient to an intensive care unit, is a syndrome in which the lungs are unable to exchange gases between inhaled air, blood in the pulmonary circulation and exhaled air. At the moment when the failure is final, there is a need for mechanical ventilation, which allows oxygenation of all tissues and sufficient minute ventilation. As long as the patient's medical condition allows, it is performed non-invasively, but when this option is exhausted, the patient needs invasive mechanical ventilation. Continuous monitoring and surveillance of a rapidly changing patient's health is needed to identify early signs of clinical deterioration and reduce the risk of iatrogenic damage. Purpose: We wanted to show the importance of continuous monitoring of the course of mechanical ventilation in a critically ill patient in the intensive care unit with an emphasis on the important role of the nurse in the timely recognition of changes. The aim of this thesis is to present the importance of parameters related to the monitoring of mechanical ventilation, and to draw attention to the values of gas analysis of arterial blood. Working methods: We used a descriptive research method of work with a review of professional and scientific literature in the field of invasive and non-invasive mechanical ventilation. The time frame for inclusion were the articles, published between 2009 and 2021. In order to achieve the set goals, a content analysis of 41 articles was made. Results: The nurse is constantly present with the patient, so her role in identifying dangerous changes in the patient's health is extremely important. Pulse oximetry and capnography are used to monitor and maintain effective ventilation. It is also necessary to be familiar with the input parameters of the fan, such as tidal volume and respiratory rate. When all these parameters are within normal limits and the patient breathes effectively mechanically, a gas analysis of arterial blood is performed after a certain time, to assess the state of acid-base balance. Discussion and conclusion: The nurse must be familiar with the functions of the ventilator, the methods of ventilation, and the causes of respiratory distress and non-compliance with the ventilator, as the first person next to the patient with a ventilator who recognizes these changes. Based on knowledge and experience, a nurse can make an important contribution to safe and quality patient-centered care. Due to the rapid development in nursing, medicine and technology, it is necessary to continuously monitor innovations with an emphasis on professional development and education of all health professionals involved in the medical treatment of this vulnerable group of critically ill patients.