Editing Ventilator (section)

=== Safety-critical system ===
As failure may result in death, mechanical ventilation systems are classified as [[safety-critical system]]s, and precautions must be taken to ensure that they are highly reliable, including their [[power-supply|power supply]]. Ventilatory failure is the inability to sustain a sufficient rate of CO<sub>2</sub> elimination to maintain a stable pH without mechanical assistance, muscle fatigue, or intolerable dyspnea.<ref>Marini, John J., Dries, David J... ''Critical Care Medicine: The Essentials and More''. 5th Edition. Two Commerce Square, 2001 Market Street, Philadelphia, PA 19103 USA:Lippincott Williams & Wilkins; 2019.  Available from: Books@Ovid at http://ovidsp.ovid.com.  Accessed January 12, 2021.</ref> Mechanical ventilators are therefore carefully designed so that no [[single point of failure]] can endanger the patient. They may have manual backup mechanisms to enable hand-driven respiration in the absence of power (such as the mechanical ventilator integrated into an [[anaesthetic machine]]). They may also have safety valves, which open to atmosphere in the absence of power to act as an anti-suffocation valve for spontaneous breathing of the patient. Some systems are also equipped with compressed-gas tanks, air compressors or backup batteries to provide ventilation in case of power failure or defective gas supplies, and methods to operate or call for help if their mechanisms or software fail.<ref>{{cite news |last1=Johnson |first1=Carolyn Y. |last2=Cha |first2=Ariana Eunjung |title=The dark side of ventilators: Those hooked up for long periods face difficult recoveries |url=https://www.washingtonpost.com/health/2020/04/03/coronavirus-survivors-recovery |access-date=8 April 2020 |newspaper=[[The Washington Post]] |language=en}}</ref>  [[Power outage|Power failures]], such as during a natural disaster, can create a life-threatening emergency for people using ventilators in a home care setting.<ref name=":3">{{Cite web|last=Huff|first=Charlotte|date=2021-05-12|title=The People in Danger the Minute the Power Goes Out|url=https://slate.com/technology/2021/05/climate-change-power-grid-home-medical-care-electricity.html|access-date=2021-05-18|website=[[Slate (magazine)|Slate]]|language=en}}</ref>  Battery power may be sufficient for a brief loss of electricity, but longer power outages may require going to a hospital.<ref name=":3" />