This pilot study aims to examine the relationship between continuously measured CareGuide™ muscle oxygen saturation (SmO2), tissue pH and data provided from standard monitoring techniques during the care of subjects with suspected established (Cohort A) or emerging (Cohort B) shock in the intensive care unit (ICU).

Approximately 50 subjects meeting recruitment criteria will be enrolled with a minimum of 20 subjects meeting entry criteria for established shock (Cohort A).

Noninvasive near-infrared spectroscopy CareGuide™ measurements of SmO2, tissue pH and hematocrit will be collected from enrollment through device removal. These data will be compared to specific hemodynamic and laboratory parameters obtained as a part of routine care during the CareGuide™ monitoring period.

Inclusion Criteria:

Subjects who are:

1. To be admitted to the intensive care unit
2. At least 18 years of age
3. Men or Women
4. Informed consent from subject or surrogate
5. Clinical diagnosis of established (Cohort A) or emerging (Cohort B) shock, as described above.

Exclusion Criteria:

Subjects with:

1. Body mass index >37
2. Trauma (primary diagnosis)
3. Pregnancy
4. Non-global conditions leading to regional increased lactate production (e.g. isolated thrombotic or embolic phenomena, limb, compartment syndrome)
5. Known untreated hypothyroidism
6. Known hypersensitivity to medical adhesives
7. Suspected carbon monoxide poisoning or methemoglobinemia
8. Goals of care restricting vital sign acquisition
9. Family member of investigators or study staff

Our study population is made up of adults admitted to an ICU with established or emerging shock.