Preoperative Cognitive Screening in Older Surgical Patients Utility for Predicting Morbidity

The overriding hypothesis is that preoperative cognitive impairment is a risk factor for
poor surgical outcomes in seniors and that preoperative screening is superior to standard or
systematic clinical processes for identifying at-risk patients. The first objective is to
assess the marginal benefit of structured preoperative cognitive screening relative to
standard or systematic preoperative evaluation for identifying seniors with likely cognitive
impairment. The second objective is to determine whether preoperative cognitive impairment
predicts postoperative outcome. This project is designed as a prospective, single-center
observational study. The cohort will consist of 250 consenting subjects ≥ 65 years of age
who present to the BWH Weiner Center for Preoperative Evaluation (CPE) prior to elective
lower extremity joint replacement surgery. These surgeries are selected because they are
common in this age group, associated with significant morbidity, and along with dementia are
considered a priority area (bone and joint conditions) by AHRQ. These ages are chosen as
significant clinical data demonstrate increased cognitive impairment in community dwelling
elders. Eligibility criteria include: patients ≥ 65 years of age with an ASA physical status
of I-IV presenting for elective joint replacement. Exclusion criteria will include planned
ICU admission postoperatively, uncorrected vision or hearing impairment (unable to see
pictures or read or hear instructions); limited use of the dominant hand (limited ability to
draw); and or inability to speak, read, or understand English. Study staff will use the CPE
computerized scheduling system, which is updated continuously in real time and captures
relevant information such as age and procedure, to identify potential subjects. When
patients check in with the receptionist in the CPE for their appointment they will be
notified that they (and their surrogate) may be eligible to participate in a study in the
CPE involving patients over the age of 65. The receptionist will then provide them with a
brochure about the study that includes information about the purpose of the study, the risks
to the patient, and the potential benefits to society. The patient will then be asked if
they are willing to speak with one of the study investigators and only those patients that
agree to speak with a study investigator will be approached. Patients with known cognitive
impairment will be included in the study to determine whether this information is included
in the preoperative evaluation form. They will sign their own consent if they are capable
and going to sign their surgical procedure consent. In the event that the patient is not
capable of signing their own consent a surrogate will be asked to provide consent with
assent from the patient. In our prior studies with similar patient populations less than 1%
had documented cognitive impairment. The staff member will then describe the goals and risks
of the study in a quiet room in the PATC and ask the patient (and their surrogate where
appropriate) if they choose to participate. After all questions have been answered and the
patient has the opportunity to read the consent form, written consent will be obtained by
one of the study investigators. After obtaining consent, study staff will gain information
about the patient's age and years of education. Study staff will administer standard
instruments to assess health and functional status (basic and instrumental activities of
daily living [ADLs and IADLs, respectively, and the WHODAS]). The World Health Organization
Disability Scale 2.0 (WHODAS) is an alternative to the SF36 to measure physical health and
disability.

In addition, patients will be asked if they've had a fall within the last 6 months, whether
they've been evaluated for a change in memory or thinking, who accompanied them to their
appointment, their employment status, and their living situation (alone, institutionalized,
living with family members) in a patient survey. The study staff will also administer the
MiniCog, a simple cognitive screening tool that takes just 2-4 min to complete and has
little or no education, language, or race bias. In addition, the Animal Fluency Test will be
administered, which is a short cognitive screen that takes one minute to complete. Other
measures of cognitive impairment will be obtained by study staff through: documentation on
the patient's standard preoperative form, patient or informant report of diagnosis or
evaluation for cognitive impairment or memory concerns, and systematic medical record
review.

During their routine preoperative blood draw the phlebotomist will be provided with three
heparinized blood tube labeled with only the patient's study ID number that will be returned
to the investigative team and processed within 30 minutes of the blood draw. Briefly, half
of the sample would be spun down and plasma harvested and stored at -80 degrees C and when
an adequate sample size obtained used to measure inflammatory cytokines by ELISA. The
remainder of the sample will be divided into 1-ml aliquots and incubated at 37°C for 15 min
with phosphate-buffered saline (PBS) (control), 100 ng/ml interleukin (IL)-6, 100 ng/ml
IL-10, or a combination of 100 ng/mlIL-2 and 2 ng/ml granulocyte macrophage
colony-stimulating factor, or 1g/ml lipopolysaccharide. Blood samples will be resuspended in
1.4 ml stabilizing buffer and incubated for 10 min at room temperature for fixation in PFA,
cooled to 4C, and stored at 80C until further processing for flow cytometry to determine the
immune response of the white blood cells to a ex-vivo immune challenge and whether these
correlate with Mini-Cog score or the development of delirium.

Each enrolled patient will receive a business card listing the investigators' contact
information and be advised to expect a follow up telephone call 6 months and 1 year after
surgery to verify data elements and reassess functional outcome. Delirium will be assessed
prospectively once per day on postoperative days 1, 2, and 3 by a trained study team member
using the Confusion Assessment Method [CAM]. Delirium is most common on postoperative days
1-3 and the CAM is a well-validated measure of delirium in surgical patients. For functional
status, the WHODAS will be administered 6-12 months postoperatively either by personnel in
the surgeon's office as part of routine follow up or by study staff or by telephone.
Investigators will also collect information on secondary outcomes including duration of PATC
visit, presence of an advanced directive, whether they had surgical procedure, time to PACU
discharge, discharge to place other than home (rehabilitation, skilled nursing facility),
hospital length of stay (LOS), in hospital complications, perioperative variables including
drugs administered, BIS, estimated blood loss, blood transfusions, fluid administered, blood
pressure, oxygen saturation, 30-day reoperation or readmission rate, and 30-day and 1-year
mortality. These outcomes are recorded in the medical record, the BWH Balanced Scorecard, an
electronic database of all hospitalized patients that tabulates 31 elements of the hospital
event, or the BWH Research Patient Database Enhanced Query. Data will also be confirmed by a
follow up telephone interview. Thirty day and 1 year mortality will be recorded.

Inclusion Criteria:

- consenting patients ≥ 65 years of age

- undergoing upcoming elective lower joint replacement surgery

Exclusion Criteria:

- planned ICU admission postoperatively

- uncorrected vision or hearing impairment

- limited use of the dominant hand

- inability to speak, read, or understand English