missed moderate-severe ards window (>72hrs) - window starts when patient is intubated with a qualifying p/f ratio of ≤ 200 with peep ≥ 8 cm h2o or on high flow nasal oxygen with well-fitting nasal cannula with flow ≥ 40 lpm and fio2 ≥ 0.65 or on non-invasive pressure ventilation with peep ≥ 8 cm h2o and fio2 ≥ 0.6. missed nmb window: (>48 hrs) missed mechanical ventilation window (>7 days) refractory hypotension (continuous infusion of >0.3 mcg/kg/min of norepinephrine or equivalent dose of other vasopressors within 2 hours prior to randomization) core temperature <35.5°c for ≥6 hours while not receiving crrt on day of randomization significant, active bleeding (>3u blood products and/or surgical/ir intervention) on day of randomization platelets <10k/mm3 (uncorrected) on day of randomization active hematologic malignancy skin process that precludes cooling device moribund, not likely to survive 72h pre-morbid condition makes it unlikely that patient will survive 28 days do not resuscitate status at time of randomization (excluding patients receiving full support except cpr for cardiac arrest) not likely to remain intubated for ≥48h physician of record unwilling to participate severe underlying lung disease needs ≥ 2 lpm home o2 on bipap (except for osa) prior lung transplantation pregnant at time of randomization bmi consistently >50 kg/m2 known nyha class iv heart disease acute coronary syndrome (mi, unstable angina) within 30 days of randomization cardiac arrest within 30 days of randomization burns over >20% of the body surface severe chronic liver disease (child-pugh score 12-15) previously randomized in chill study simultaneous enrollment in another interventional trial started during the current hospitalization. on ecmo during the current hospitalization.

missed moderate-severe ards window (>72hrs) - window starts when patient is intubated with a qualifying p/f ratio of ≤ 200 with peep ≥ 8 cm h2o or on high flow nasal oxygen with well-fitting nasal cannula with flow ≥ 40 lpm and fio2 ≥ 0.65 or on non-invasive pressure ventilation with peep ≥ 8 cm h2o and fio2 ≥ 0.6. missed nmb window: (>48 hrs) missed mechanical ventilation window (>7 days) refractory hypotension (continuous infusion of >0.3 mcg/kg/min of norepinephrine or equivalent dose of other vasopressors within 2 hours prior to randomization) core temperature <35.5°c for ≥6 hours while not receiving crrt on day of randomization significant, active bleeding (>3u blood products and/or surgical/ir intervention) on day of randomization platelets <10k/mm3 (uncorrected) on day of randomization active hematologic malignancy skin process that precludes cooling device moribund, not likely to survive 72h pre-morbid condition makes it unlikely that patient will survive 28 days do not resuscitate status at time of randomization (excluding patients receiving full support except cpr for cardiac arrest) not likely to remain intubated for ≥48h physician of record unwilling to participate severe underlying lung disease needs ≥ 2 lpm home o2 on bipap (except for osa) prior lung transplantation pregnant at time of randomization bmi consistently >50 kg/m2 known nyha class iv heart disease acute coronary syndrome (mi, unstable angina) within 30 days of randomization cardiac arrest within 30 days of randomization burns over >20% of the body surface severe chronic liver disease (child-pugh score 12-15) previously randomized in chill study simultaneous enrollment in another interventional trial started during the current hospitalization. on ecmo during the current hospitalization.

missed moderate-severe ards window (>72hrs) - window starts when patient is intubated with a qualifying p/f ratio of ≤ 200 with peep ≥ 8 cm h2o or on high flow oxygen with well-fitting nasal cannula with flow ≥ 65 lpm and fio2 ≥ 0.65 or on non-invasive pressure ventilation with peep ≥ 8 cm h2o and fio2 ≤ 0.6. missed nmb window: (>48 hrs) missed mechanical ventilation window (>7 days) refractory hypotension (continuous infusion of >0.2 mcg/kg/min of norepinephrine or equivalent dose of other pressors for >6 continuous hours prior to randomization) core temperature <35.5°c for ≥6 hours while not receiving crrt on day of randomization significant, active bleeding (>3u blood products and/or surgical/ir intervention) on day of randomization platelets <10k/mm3 (uncorrected) on day of randomization active hematologic malignancy skin process that precludes cooling device moribund, not likely to survive 72h pre-morbid condition makes it unlikely that patient will survive 28 days do not resuscitate status at time of randomization not likely to remain intubated for ≥48h physician of record unwilling to participate severe underlying lung disease needs ≥ 2 lpm home o2 on bipap (except for osa) prior lung transplantation pregnant at time of randomization bmi consistently >50 kg/m2 known nyha class iv heart disease acute coronary syndrome (mi, unstable angina) within 30 days of randomization cardiac arrest within 30 days of randomization burns over >20% of the body surface severe chronic liver disease (child-pugh score 12-15) previously randomized in chill study simultaneous enrollment in another interventional trial

missed moderate-severe ards window (>72hrs) - window starts when patient is intubated with a qualifying p/f ratio of ≤ 200 with peep ≥ 8 cm h2o or on high flow oxygen with well-fitting nasal cannula with flow ≥ 65 lpm and fio2 ≥ 0.65 or on non-invasive pressure ventilation with peep ≥ 8 cm h2o and fio2 ≤ 0.6. missed nmb window: (>48 hrs) missed mechanical ventilation window (>7 days) refractory hypotension (continuous infusion of >0.2 mcg/kg/min of norepinephrine or equivalent dose of other pressors for >6 continuous hours prior to randomization) core temperature <35.5°c for ≥6 hours while not receiving crrt on day of randomization significant, active bleeding (>3u blood products and/or surgical/ir intervention) on day of randomization platelets <10k/mm3 (uncorrected) on day of randomization active hematologic malignancy skin process that precludes cooling device moribund, not likely to survive 72h pre-morbid condition makes it unlikely that patient will survive 28 days do not resuscitate status at time of randomization not likely to remain intubated for ≥48h physician of record unwilling to participate severe underlying lung disease needs ≥ 2 lpm home o2 on bipap (except for osa) prior lung transplantation pregnant at time of randomization bmi consistently >50 kg/m2 known nyha class iv heart disease acute coronary syndrome (mi, unstable angina) within 30 days of randomization cardiac arrest within 30 days of randomization burns over >20% of the body surface severe chronic liver disease (child-pugh score 12-15) previously randomized in chill study simultaneous enrollment in another interventional trial

missed ards window (>72hrs) missed nmb window: (>48 hrs) missed mechanical ventilation window (>7 days) refractory hypotension (continuous infusion of >0.2 mcg/kg/min of norepinephrine or equivalent dose for >6 h prior to randomization) core temperature <35.5°c while not receiving crrt on day of randomization significant, active bleeding (>3u blood products and/or surgical/ir intervention) on day of randomization platelets <10k/mm3 (uncorrected) on day of randomization active hematologic malignancy skin process that precludes cooling device moribund, not likely to survive 72h pre-morbid condition makes it unlikely that patient will survive 28 days do not resuscitate status at time of randomization not likely to remain intubated for ≥48h physician of record unwilling to participate severe underlying lung disease on home o2 on bipap (except for osa) prior lung transplantation pregnant at time of randomization bmi consistently >50 kg/m2 known nyha class iv heart disease acute coronary syndrome (mi, unstable angina) within 30 days of randomization cardiac arrest within 30 days of randomization burns over >20% of the body surface severe chronic liver disease (child-pugh score 12-15) previously randomized in chill study simultaneous enrollment in another interventional trial

missed ards window (>72hrs) missed nmb window: (>48 hrs) missed mechanical ventilation window (>7 days) refractory hypotension (continuous infusion of >0.2 mcg/kg/min of norepinephrine or equivalent dose for >6 h prior to randomization) core temperature <35.5°c while not receiving crrt on day of randomization significant, active bleeding (>3u blood products and/or surgical/ir intervention) on day of randomization platelets <10k/mm3 (uncorrected) on day of randomization active hematologic malignancy skin process that precludes cooling device moribund, not likely to survive 72h pre-morbid condition makes it unlikely that patient will survive 28 days do not resuscitate status at time of randomization not likely to remain intubated for ≥48h physician of record unwilling to participate severe underlying lung disease on home o2 on bipap (except for osa) prior lung transplantation pregnant at time of randomization bmi consistently >50 kg/m2 known nyha class iv heart disease acute coronary syndrome (mi, unstable angina) within 30 days of randomization cardiac arrest within 30 days of randomization burns over >20% of the body surface severe chronic liver disease (child-pugh score 12-15) previously randomized in chill study simultaneous enrollment in another interventional trial

missed ards window (>48hrs) missed nmb window: (>12 hrs) missed mechanical ventilation window (>7 days) refractory hypotension (> 0.2 mcg/kg/min of norepinephrine or equivalent dose for 6 h or longer) core temperature <35.5°c while not receiving crrt patient is unable to give consent and no legally authorized representative is available significant, active bleeding (>3u blood products and/or surgical/ir intervention) platelets <10k/mm3 (uncorrected) active hematologic malignancy skin process that precludes cooling device moribund, not likely to survive 72h pre-morbid condition makes it unlikely that patient will survive 28 days do not resuscitate status not likely to remain intubated for ≥48h physician of record unwilling to participate severe underlying lung disease on home o2 on bipap (except for osa) prior lung transplantation pregnant bmi >50 kg/m2 known nyha class iv heart disease acute coronary syndrome past 30 days (mi, unstable angina) cardiac arrest within 30 days of enrollment burns over >20% of the body surface severe chronic liver disease (child-pugh score 12-15) previously randomized in chill study

missed ards window (>48hrs) missed nmb window: (>12 hrs) missed mechanical ventilation window (>7 days) refractory hypotension (> 0.2 mcg/kg/min of norepinephrine or equivalent dose for 6 h or longer) core temperature <35.5°c while not receiving crrt patient is unable to give consent and no legally authorized representative is available significant, active bleeding (>3u blood products and/or surgical/ir intervention) platelets <10k/mm3 (uncorrected) active hematologic malignancy skin process that precludes cooling device moribund, not likely to survive 72h pre-morbid condition makes it unlikely that patient will survive 28 days do not resuscitate status not likely to remain intubated for ≥48h physician of record unwilling to participate severe underlying lung disease on home o2 on bipap (except for osa) prior lung transplantation pregnant bmi >50 kg/m2 known nyha class iv heart disease acute coronary syndrome past 30 days (mi, unstable angina) cardiac arrest within 30 days of enrollment burns over >20% of the body surface severe chronic liver disease (child-pugh score 12-15) previously randomized in chill study