This type of coma is usually reversible once the blood sugar is corrected. Oxygen deprivation: Oxygen is essential for brain function. Cardiac arrest causes a sudden cutoff of blood flow and oxygen to the brain, called hypoxia or anoxia.
The external power supply is the AC power adapter that converts household AC electricity voltages to the much lower DC voltages needed to charge a mobile phone's internal battery.
Having a power inverter means you'll always have access to an alternative power source. Thanks to Amazon.com's wide range of low-priced power inverters, you can choose exactly what you need, from a model powerful enough to keep your laptop juiced up to a model supplying over 3,000 watts of power.