Volunteers above the age of 18 and below the age of 60 who agreed to participate in the study were not exposed to any interventional intervention other than those routinely applied to the patient during and after the administration of the clinical standard anesthesia protocol. The value indicating the brain's response to hypnotic substances, the vapor concentration in the lung alveoli and the minimum amount of anesthesia gas used will be recorded at certain times. The aim of the researchers in the study was to observe the effect of two different fresh gas flow rates on the amount and cost of waste gas released into the atmosphere.

Anesthetic management of a patient receiving general anesthesia consists of induction, maintenance and termination periods. In the "wash in period" (saturation of the circuit between the anesthesia device and the patient), high fresh gas flows, usually 2-4 l/min fresh gas flow (50% oxygen and 50% air/nitrous oxide mixture) are used. Inhaled anesthetic agents are routinely used in resuscitation. However, the part of this inhaled agent that is not used by the patient is released into the atmosphere and environment. The higher the flow of fresh gas administered, the greater the proportion not used by the patient and discharged into the atmosphere. These waste gases contribute significantly to the greenhouse effect in the atmosphere. Occupational exposure (liver-kidney disease, neurologic disease, cancer, spontaneous abortions, etc. in healthcare workers) accounts for the portion released into the environment. The consumption and cost of inhalation agents depends on the fresh gas flow rate, vaporizer setting and duration of anesthesia. It has been observed that reducing the fresh gas flow rate significantly reduces the cost. The aim of the researchers in the study was to observe the effect of a fresh gas flow rate of 1 l/min to 4 l/min on the amount of waste gas discharged into the atmosphere and thus on the cost of inhaled agents.

Inclusion Criteria:

• ASA I-II risk group patients Duration of surgery between 2 hours and 4 hours, cases with general anesthesia

Exclusion Criteria:

• Patient refusal to participate in the study
• Under 18 years old BMI>40
• Patients receiving invasive mechanical ventilator support in the last 1 month
• Patients who have received chemotherapy or radiotherapy in the last 2 months
• Those with severe lung disease (COPD, asthma, pulmonary infection, bronchiectasis, previous need for non-invasive mechanical ventilation, oxygen therapy or steroid therapy for acute attack)
• Known severe pulmonary hypertension
• Smoke poisoning (carbon monoxide, cyanide poisoning)
• Alcohol or acetone poisoning
• Malignant hyperthermia
• Intracranial tumor
• Hemodynamic instability
• Shock
• Neuromuscular disease
• Pathologies causing increased intracranial and intraocular pressure
• Those with severe cardiac arrhythmias Those with -EF<30
• Severe peripheral arterial disease
• Patients with liver and kidney dysfunction

Male or female Between 18-60 years of age ASA I-II risk group patients with general anesthesia Duration of surgery between 2 hours and 4 hours