The purpose of this study is to define the natural history and causes of chronic critical illness (CCI) in surgical intensive care patients who have had sepsis. The investigator wants to study a sub-population of sepsis patients that have intra-abdominal sepsis. The purpose of this research study is to define the acute changes in frailty (weakness, slowness, loss of muscle mass), comorbidity (medical problems) and disability (difficulty with mobility and performing routine daily functions) after having an infection that is located in the abdominal cavity or torso. The investigator believes having severe infection contributes to acute and permanent changes in these areas, especially in those of advanced age.

This is a prospective study aimed at identifying the frequency, natural history and long term outcomes of CCI and PICS in the survivors of Intra-abdominal sepsis.

In addition to the in-hospital clinical data collected from the parent study, pre and post-sepsis measurements of frailty, comorbidity and disability will be obtained via questionnaires and the electronic health records. Frailty, comorbidity and disability assessments will also be completed at the three, six, and 12 month follow up assessments.

Frailty measures A frailty index will be determined as a combination of factors.

An older adult is considered physically vulnerable when they experience:

1. muscle weakness
2. fatigue
3. low physical activity, and unintentional loss in body weight, which has been agreed upon by a consensus of experts.

Two additional non-intravenous contrasted CT scans will be obtained at 3 and 12 months as part of the study protocol to assess for interval change in SMI/sarcopenia.

Objective mobility and activity monitoring will be performed to supplement assessment of frailty and disability. Wearable monitors (similar in size and appearance to a "smart watch" have received significant attention because they offer minimal burden, objectivity, versatility and low cost for assessing activity and mobility patterns. The monitor is similar in shape and size to a standard wrist watch. Thus, it will have minimal burden to patients. Each monitor will be fitted on the wrist and worn for 24 hours a day, but can be quickly removed for medical procedures, patient care or hygiene needs. Patients will wear the monitor for their entire length of stay in the hospital. It will be removed at discharge. Post-discharge, patients will be sent a monitor to wear for up to 10 days at four different time points: 3 months, 6 months and 12 months post-discharge. If study subjects are hospitalized long enough that discharge is within 30 days of the 3 month follow up, the 1 month post discharge monitoring period will be deferred. Outcomes include steps per day, total movements per day, minutes being sedentary and minutes moving at various intensities (e.g. light, moderate and vigorous).

Inclusion Criteria:

• Admission to the surgery or trauma ICU where clinical care can be managed by surgical critical care guided by standard operating procedures.
• Age ≥18 years
• Diagnosis of sepsis, severe sepsis, or septic shock
• Entrance into the standard-of-care sepsis protocol
• Ability to obtain patient/legally authorized representative informed consent.

Exclusion Criteria:

• Significant traumatic brain injury (evidence of neurologic injury on CT scan and a best Glascow Coma Scale <8 within 24 hours of injury)
• Refractory shock (i.e., patients who die within 12 hours)
• Alternative or confounding diagnosis causing shock state (e.g., myocardial infarction or pulmonary embolus)
• Uncontrollable source of sepsis (e.g., irreversible disease state such as unresectable dead bowel),
• Patients deemed to be futile care or have advanced care directives limiting resuscitative efforts such as patient or patient's family who are not committed to aggressive management of the patient's condition. Expected lifespan of the patient is less than 3 months due to severe pre-existing comorbidities (ex. Recurrent, advanced or metastatic cancer).
• Severe Congestive Heart Failure (NY Heart Association Class IV)
• Child-Pugh Class C liver disease or pre-liver transplant.
• Known HIV infection with CD4 count<200 cells/mm3,
• Organ transplant recipient on immunosuppressive agents
• Known pregnancy
• Inability to obtain informed consent
• Prisoners
• Institutionalized patients
• Chemotherapy or radiotherapy within 30 days prior to sepsis
• Spinal cord injuries resulting in permanent sensory and/or motor deficits.

Intra-Abdominal Sepsis Patients