Knowing when to liberate critically ill patients from mechanical ventilation (i.e. extubation) is of great importance as both prolonged ventilation and failed extubation are associated with increased morbidity, mortality & costs. The study objective is to improve the safety of extubation by harnessing hidden information contained in the patterns of variation of heart and respiratory rate measured over intervals-in-time.

As a standard of care for patients who are intubated in the ICU; to assess ability to be extubated, a Spontaneous Breathing Trial (SBT) is performed, where the level of ventilator support is reduced, and patient's response is observed to predict if they will tolerate extubation.

Spontaneous breathing trials (SBTs) are standard of care in assessing extubation readiness; however, there are no universally accepted guidelines regarding their precise performance and reporting.

Given that health is associated with a high degree of variation of physiologic parameters (e.g. heart and respiratory rate), and illness & stress are associated with a loss of variability, the investigators have demonstrated that maintaining a high level of heart rate (HRV) and respiratory rate variability (RRV) prior to and throughout the Spontaneous Breathing Trial (SBT) will predict successful extubation, and a reduction in heart rate (HRV) and respiratory rate variability (RRV) predicts extubation failure.

Research to date has already demonstrated the added prognostic value and the investigators have derived a predictive model based on continuous monitoring of respiratory rate variability (RRV). The investigators are now poised to evaluate Extubation Advisor (EA) software with the overall goal to transform monitoring and improve care.

This study is a mixed methods, pilot phase I observational study of the clinical implementation of a novel clinical decision support product, Extubation Advisor.TM In this study the investigators will evaluate the feedback of RTs as well as the feedback of MDs post-treatment (extubation) decision.

Questionnaires will be sent to Respiratory Therapists (RT's) and Medical Doctors (MD's) to solicit feedback on the electronic Spontaneous Breathing Trial (SBT) Case Report Form (CRF) and the Extubation Advisor TM (EA) report. All questionnaires will be answered based on a rating scale of 1-5 where 1 is unacceptable and 5 is excellent.

As this proposed study is observational and has no impact on patient care/outcomes, and to avoid bias associated with requiring consent, the investigators believe this study represents one of the limited circumstances under which waived consent may be permitted.

Inclusion Criteria:

1. patients who have been or are expected to be on mechanical ventilation for > 48 hours in total prior to extubation,
2. patients who are ready for Spontaneous Breathing Test (SBT) for assessment for extubation,
3. the patients who are able to tolerate pressure support ventilation ≤ 14 cm H2O (SpO2 ≥ 90% with FiO2 ≤ 40% and PEEP 10 ≤ cm H20,
4. patients who are hemodynamically stable (off vasopressors or on low levels of vasopressors: phenylephrine < 50 ug/min; norepinephrine < 5 ug/min; dobutamine < 5 ug/kg/min; milrinone< 0.4 ug/kg/min),
5. patients whose neurological status is stable (no deterioration in the last 24 hrs, intact respiratory drive and ICP <20),
6. patients who have intact airway reflexes (adequate cough with suctioning and a gag reflex), and
7. patient who are in normal sinus rhythm at the time of the SBT (no pacemaker).

Exclusion Criteria:

1. patients who have "do not re-intubate" order documented on their chart or if withdrawal of life support is anticipated,
2. patients who have a tracheostomy,
3. patients who suffer from known or suspected severe myopathy or neuropathy (i.e. myasthenia gravis, Guillain-Barré syndrome) or quadriplegia,
4. patients who have been previously extubated during the same ICU admission.

Patients who are being considered for extubation in the ICU