New Onset Weakness in Critically Ill Patients and the Risk of Death and Recurrent ICU Admission

This study seeks to define the morbidity of critical care polyneuropathy and to confirm that this diagnosis is, in fact, independently associated with increased mortality. Secondary information regarding the reasons for ICU readmission in patients with weakness may help in formulating cogent discharge strategies for these patients. Measurement of weakness using handgrip strength may provide a useful surrogate marker for weakness that may be more easily and uniformly applied. Primary hypothesis: * The development of ICU-associated weakness is independently associated with excess attributable mortality. Secondary hypothesis: * The development of ICU-associated weakness is associated with an increased need for ICU readmission. * Readmission to the ICU will be a result of the development of recurrent respiratory failure or insufficiency * Handgrip strength testing will detect ICU-associated weakness with an equivalent sensitivity as the comprehensive bedside muscle strength exam.