 Currently, the MSICU uses an extubation readiness test ERT. This test determines if patients are eligible for discontinuation of mechanical ventilation. This test consist of a daily screen of changing the FIO2 fraction of inspired oxygen to 50 left at current setting if lower than 50 and decrease the PEEP to 5 cmH2O. Patients unable to maintain saturation SpO2 of 95, or become tachypneic, or appear uncomfortable failed the test; those who maintained SpO2 of 95 or higher have their mode of ventilation changed to minimal pressure support PSV. Minimal PSV was determined by the endotracheal tube ETT size. Patients were classified as failing the test if at any time in the two hour period their SpO2 was less than 95, their exhaled tidal volume was less than 5 mLkg ideal body weight, or their respiratory rate was outside of the acceptable range for age. If the patient fails an ERT they are returned to their previous ventilator setting and evaluated for extubation readiness in 24 hours. It is understood that sedation is one of the primary caused of extubation failure, however there is additional concern regarding the diaphragmatic function. When the mechanical load of the respiratory system is too large or continues for a long period of time, the diaphragm can develop contractile fatigue4. This fatigue can be short or long term. Short term is also known as high-frequency fatigue that results from the accumulation of inorganic phosphate5, failure of the membrane electrical potential6, and to a lesser extent intramuscular acidosis7, but recover quickly. On the other hand long term fatigue, otherwise known as low-frequency fatigue is consistent with muscle injury 8, 9 and can persist for days. Being able to identify what type of diaphragm fatigue could lead us to hold on extubation readiness testing as to not re-injury. 