Patients under general anesthesia must undergo continuous physiological monitoring to ensure safety. In the US, the American Society of Anesthesiologists (ASA) have established minimum monitoring guidelines for patients receiving general anesthesia, regional anesthesia, or sedation. This includes electrocardiography (ECG), heart rate, blood pressure, inspired and expired gases, oxygen saturation of the blood (pulse oximetry), and temperature.  In the UK the Association of Anaesthetists (AAGBI) have set minimum monitoring guidelines for general and regional anesthesia. For minor surgery, this generally includes monitoring of heart rate , oxygen saturation , blood pressure , and inspired and expired concentrations for oxygen , carbon dioxide , and inhalational anesthetic agents. For more invasive surgery, monitoring may also include temperature, urine output, blood pressure, central venous pressure , pulmonary artery pressure and pulmonary artery occlusion pressure , cardiac output , cerebral activity , and neuromuscular function. In addition, the operating room environment must be monitored for ambient temperature and humidity, as well as for accumulation of exhaled inhalational anesthetic agents, which might be deleterious to the health of operating room personnel. 
Use of QVAR with a spacer device in children less than 5 years of age is not recommended. In vitro dose characterization studies were performed with QVAR 40 mcg/actuation with the OptiChamber and AeroChamber Plus ® spacer utilizing inspiratory flows representative of children under 5 years old. These studies indicated that the amount of medication delivered through the spacing device decreased rapidly with increasing wait times of 5 to 10 seconds as shown in Table 2. If QVAR is used with a spacer device, it is important to inhale immediately.
Regardless of which inhalant is used, inhaling vapours or gases can lead to injury or death. One major risk is hypoxia (lack of oxygen), which can occur due to inhaling fumes from a plastic bag, or from using proper inhalation mask equipment (., a medical mask for nitrous oxide) but not adding oxygen or room air. Another danger is freezing the throat. When a gas that was stored under high pressure is released, it cools abruptly and can cause frostbite if it is inhaled directly from the container. This can occur, for example, with inhaling nitrous oxide. When nitrous oxide is used as an automotive power adder , its cooling effect is used to make the fuel-air charge denser. In a person, this effect is potentially lethal). Many inhalants are volatile organic chemicals and can catch fire or explode, especially when combined with smoking. As with many other drugs, users may also injure themselves due to loss of coordination or impaired judgment, especially if they attempt to drive.