Table 2.
Zero activity epochs in the ICU, as measured using actigraphy
| n (N=34) | Total Epochs (N= 189,595) | Zero Activity Epochs, Proportion (95% CI)a | Unadjusted Difference (95% CI)b | P value | Adjusted Difference (95% CI)b | P value | |
|---|---|---|---|---|---|---|---|
| Baseline Variables | |||||||
| Age Tertile | |||||||
| 25–50 years old | 12 | 66,196 | 64 (49, 77) | REF | REF | REF | REF |
| 51–65 years old | 11 | 61,471 | 62 (53, 70) | −2 (−17, 13) | 0.79 | −9 (−20, 2) | 0.13 |
| 66–87 years old | 11 | 61,928 | 68 (54, 80) | 4 (−12, 21) | 0.61 | 3 (−9, 15) | 0.67 |
| Gender | |||||||
| Female | 17 | 94,607 | 68 (57, 77) | REF | REF | REF | REF |
| Male | 17 | 94,988 | 61 (52, 70) | −7 (−19, 6) | 0.28 | −2 (−14, 11) | 0.78 |
| Race | |||||||
| White | 21 | 117,884 | 62 (53, 71) | REF | REF | REF | REF |
| Non-white | 13 | 71,711 | 69 (58, 78) | 7 (−5, 19) | 0.28 | 6 (−4, 15) | 0.26 |
| Ambulatory Prior to ICU | |||||||
| No | 2 | 9,822 | 70 (0, 100) | REF | REF | REF | REF |
| Yes | 32 | 179,773 | 65 (57, 71) | −5 (−24, 14) | 0.60 | 2 (−20, 23) | 0.89 |
| BMI Classification | |||||||
| Underweight (BMI <18) | 3 | 16,905 | 47 (18, 78) | −14 (−31, 2) | 0.09 | −12 (−36, 11) | 0.30 |
| Normal (BMI 18–24.9) | 13 | 71,580 | 61 (49, 72) | REF | REF | REF | REF |
| Overweight (BMI 25–29.9) | 9 | 50,496 | 74 (57, 86) | 13 (−3, 28) | 0.11 | 16 (0, 31) | 0.05 |
| Obese (BMI >30) | 9 | 50,614 | 66 (54, 77) | 5 (−9, 19) | 0.50 | 12 (3, 22) | 0.009 |
| Admission Diagnosis Category | |||||||
| Respiratory Failure | 14 | 77,045 | 67 (56, 77) | REF | REF | REF | REF |
| Gastrointestinal | 3 | 16,858 | 65 (8, 98) | −2 (−31, 26) | 0.87 | −2 (−28, 24) | 0.90 |
| Sepsis | 7 | 39,739 | 67 (45, 84) | 0 (−18, 18) | 1.00 | 2 (−14, 17) | 0.85 |
| Cardiovascular | 4 | 22,653 | 53 (27, 77) | 14 (−3, 32) | 0.10 | −8 (−20, 4) | 0.17 |
| Other | 6 | 33,300 | 64 (48, 78) | 3 (−11, 17) | 0.66 | 6 (−5, 18) | 0.29 |
| ICU Variables | |||||||
| Time of day | |||||||
| 06:00–09:59 | - | 32,121 | 62 (55, 70) | REF | REF | REF | REF |
| 10:00–13:59 | - | 27,813 | 60 (51, 68) | −3 (−9, 3) | 0.36 | −4 (−10, 2) | 0.22 |
| 14:00–17:59 | - | 32,640 | 58 (50, 66) | −4 (−10, 2) | 0.16 | −5 (−11, 1) | 0.11 |
| 18:00–21:59 | - | 32,640 | 61 (52, 69) | −2 (−8, 5) | 0.62 | −2 (−8, 4) | 0.51 |
| 22:00–01:59 | - | 32,221 | 72 (64, 78) | 9 (3, 15) | 0.003 | 9 (3, 15) | 0.002 |
| 02:00–05:59 | - | 32,160 | 76 (70, 80) | 13 (7, 19) | <0.001 | 14 (9, 19) | <0.001 |
| Average Daily SOFA Tertile | |||||||
| 0.0 – 3.5 | 13 | 72,683 | 58 (48, 52) | REF | REF | REF | REF |
| 3.6 – 7.9 | 11 | 57,409 | 60 (46, 73) | 2 (−12, 17) | 0.74 | −4 (−19, 12) | 0.65 |
| 8.0 – 18.3 | 10 | 56,802 | 77 (65, 86) | 19 (7, 32) | 0.002 | 13 (2, 24) | 0.03 |
| Mechanically Ventilated | |||||||
| Never | 23 | 129,014 | 58 (51, 64) | REF | REF | REF | REF |
| Ever | 11 | 60,581 | 79 (65, 89) | 21 (9, 33) | 0.003 | 24 (11, 38) | <0.001 |
| Received Continuous Sedation | |||||||
| Never | 27 | 150,004 | 61 (54, 67) | REF | REF | REF | REF |
| Ever | 7 | 39,591 | 81 (9, 38) | 20 (7, 33) | 0.01 | −10 (−31, 10) | 0.32 |
| Restrained | |||||||
| Never | 31 | 172,632 | 63 (56, 69) | REF | REF | REF | REF |
| Ever | 3 | 16,963 | 85 (63, 95) | 22 (14, 31) | <0.001 | −6 (−31, 19) | 0.65 |
| All Subjectsc | 34 | 189,595 | 65 (58, 71) | ||||
Abbreviations: ICU = Intensive Care Unit; BMI = Body Mass Index; SOFA = Sequential Organ Failure Assessment
a
Within-patient 95% confidence intervals
b
Derived using predictive margins of a logistic regression of zero versus nonzero activity epochs, using clustering to account for within-patient correlation of activity levels. Multivariable model involved all variables reported in this table. Expressed as marginal differences in proportion of zero activity levels.
c
For reference, a healthy adult undergoing 24-hour actigraphy exhibits 49% zeroes, with 19% from 06:00–09:59, 41% from 10:00–13:59, 35% from 14:00–17:59, 31% from 18:00–21:59, 85% from 22:00–01:59, and 83% from 02:00–05:59.