Table 1.
Characteristics of the participants
| (N = 153) | ||
|---|---|---|
| Age (years) | ||
| Mean ± SD | 71 ± 5 | |
| 64–69 | 73 (48%) | |
| 70–75 | 43 (28%) | |
| 76–80 | 37 (24%) | |
| Male sex - no. (%) | 80 (52%) | |
| Race or ethnic group, No. (%) | ||
| White | 151 (98.7%) | |
| Black | 1 (0.65%) | |
| Hispanic | 0 | |
| Asian Indian | 0 | |
| Others or unknown | 1 (0.65%) | |
| Education, No. (%) | ||
| Graduate of College or Postgraduate School | 110 (72%) | |
| Some College/Vocational/Technical Program | 17 (11%) | |
| High School Graduate/GED | 19 (12%) | |
| Less than high school graduation | 4 (3%) | |
| Unknown | 3 (2%) | |
| Height (cm) Mean ± SD | 170 ± 10 | |
| Body Weight (kg) Mean ± SD | 85 ± 17 | |
| BMI (kg/m2) Mean ± SD | 29 ± 5 | |
| ASA Class | ||
| I | 1 | |
| II | 119 | |
| III | 27 | |
| Unknown | 6 | |
| Length of Anesthesia (minutes) | 125 ± 18 | |
| Length of Surgery (minutes) | 81 ± 16 | |
| Total Hip Arthroplasty/Replacement | 72 (46%) | |
| Total Knee Arthroplasty/Replacement | 83 (54%) | |
| Estimated Blood Loss (ml) Mean ± SD | 162 ± 93 | |
| Aβ40 (Median and 25% – 75% percentile) | 4820 (3800 – 6411) pg/mL | |
| Aβ42 (Median and 25% – 75% percentile) | 570 (370 – 768) pg/mL | |
| Tau (Median and 25% – 75% percentile) | 380 (303 – 519) pg/mL | |
| Aβ40/Tau ratio (Median and 25% – 75% percentile) | 12.6 (9.2 – 16.1) | |
| Aβ42/Tau ratio (Median and 25% – 75% percentile) | 1.4 (0.9 – 2.1) | |
The length of Anesthesia was defined from the time anesthesiologists started the spinal anesthesia in the participants to the time when the participants were sent to the post-anesthesia care unit. The length of surgery was defined from the time of initial incision to the time of the closure of the skin. The values of Aβ40, Aβ42, Tau, Aβ40/Tau ratio and Aβ42/Tau ratio in the CSF of all 153 participants were obtained using ELISA methods (see text for details). ASA, American Society of Anesthesiologists; GED, general educational development; cm, centimeter; min, minute; kg, kilogram; ml, milliliter, SD, standard deviation; Aβ, β-amyloid; CSF, cerebrospinal fluid.