Materials and Methods
Sample and Setting
The institutional review board of the study site approved this study. The current study was part of a larger National Institutes of Health-funded study (1RO1NR013322-01) examining decision making of ICU FDMs. The research setting included three adult ICUs at a large tertiary care center. The study inclusion criteria for ICU patients were 1) mechanical ventilation or predicted ICU stay of greater than 5 days, 2) lack of cognitive decisional capacity, 3) age more than 18 years, and 4) has an identified FDM. Exclusion criteria for ICU patients included: 1) able to make their own care decisions and 2) family meeting planned to discuss withdrawal of life-sustaining interventions for the patient or withdrawal in process. Study inclusion criteria for FDMs of ICU patients were 1) over 18 years, 2) identified as the primary person responsible for ICU patient decision making, and 3) able to speak English.
Design
The study design was a descriptive, longitudinal, correlational study to identify coping strategies and symptoms of PTSD in ICU FDMs and the extent of the relationship between FDM coping strategies and post-ICU PTSD symptoms. An FDM may be 1) a family member previously designated by the patient as the legal durable power of attorney, 2) a family member who was verbally chosen by the patient, but legal documentation does not exist, 3) a relative, or friend, who is available and assumes the role of decision maker, or 4) a legal guardian. A research assistant (RA) rounded in the ICUs on a daily basis to identify patients and FDMs eligible for the study. Enrollment and initial interviews were obtained at the bedside (all ICU rooms were single-patient rooms) or a nearby private room according to the preference of the FDM. When a patient met the eligibility criteria for the study but the FDM was not present at the patient's bedside, the RA explained the study to the potential participant by phone and either arranged a time to meet the participant face-to-face for enrollment or conducted the interview by phone.
The study design had three data collection points: Time 1 (T1) = day 3–5 after ICU admission, Time 2 (T2) = 30 days after discharge from the hospital or death of the patient, and Time 3 (T3) = 60 days after discharge or death of the patient. The demographic form was administered at T1. The Brief COPE instrument was administered at T1 and T2. The Impact of Event Scale-Revised (IES-R) was administered at T3. At 30 days after discharge from the hospital (T2), the FDM was contacted by phone call, e-mail, or standard mail. The same process was followed at 60 days after discharge from the hospital or death of the patient (T3). Bereaved family members contacted at T2 and T3 were encouraged to pursue local bereavement support groups. A $10.00 gift card was offered prior to enrollment in the study and again at T3 upon completion of all study time points to compensate FDMs for the inconvenience of participating in the study during a difficult and stressful time and to stimulate study participation.
Measurement
Demographic Form. Patient and FDM characteristics were obtained from the FDM and the patient's medical records. Patient characteristics included age, gender, ethnicity, length of ICU stay, length of hospital stay, and final disposition of the patient at 30 days (death or discharge from ICU). FDM characteristics included age, gender, ethnicity, relationship to the patient, previous decision-making experience, documentation of patient's living will, and designation of durable power of attorney.
Brief COPE Instrument. Coping strategy was measured at T1 and T2 by the Brief COPE instrument, which is a 28-item measure of coping strategies. The Brief COPE consists of 14 subscales of two items each. The items are scored using a 4-point Likert scale with responses ranging from 1 (I haven't been doing this at all) to 4 (I have been doing this a lot). Each of the 14 subscales can be reported as a total score or a mean score with higher scores indicating more use of the particular type of coping effort. Based on conceptual and theoretical literature, several authors group the 14 subscales into three coping categories or strategies: 1) problem-focused coping, 2) emotion-focused coping, and 3) avoidant coping. Each category score is reported as a mean score ranging from 1 to 4 (Table A1, Supplemental Digital Content 1, http://links.lww.com/CCM/B207). Several authors have reported on the psychometric properties of the Brief COPE subscales and coping categories (Table A2, Supplemental Digital Content 1, http://links.lww.com/CCM/B207).
IES-R. Symptoms of posttraumatic stress were measured by the IES-R. The IES-R is a self-report scale that provides information on both the presence and severity of stress-related symptoms. Horowitz et al proposed the original IES, which was revised by Weiss and Marmar to include three subscales corresponding to the three symptom clusters of PTSD described in the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition: intrusion, avoidance, and hyperarousal The IES-R is a 22-item instrument scored using a 5-point scale ranging from 0 (not at all) to 4 (extremely) for each item. Total scores may range from 0 to 88 with higher scores indicating higher levels of posttraumatic stress symptoms. Several authors have reported on the validity and reliability of the IES-R instrument.
Data Analysis
Descriptive statistics were used to assess frequencies and variability of the data. Nominal or ordinal variables were described using absolute n and proportions. Interval/ratio variables were described using means and SDs. Bivariate associations were examined using Pearson correlations and chi-square analysis. Differences between groups were examined using dependent samples t tests, two sample t tests, and one-way analysis of variance (ANOVA). Individual-level change over time was examined using raw data change scores. Change scores for the coping strategies were derived by subtracting T1 scores from T2 scores with positive values indicating an increase in use over time and negative values indicating a decrease in use over time. Reliable Change Indices (RCI) were used to assess the statistical significance of individual-level change in variables over time. RCI was calculated as the difference between T2 and T1 scores divided by the SE of the difference in scores between time points RCI scores greater than 1.96 or less than –1.96 indicate a statistically significant change in scores over time (p < 0.05). Associations between demographic variables, coping strategies, and PTSD symptoms were evaluated using multiple regression models, after confirming that the data met test assumptions. Two-sided p values of less than 0.05 were considered statistically significant. Data were analyzed using the Statistics Package for the Social Sciences (SPSS; IBM, Armonk, NY) version 21 software. The sample size was determined on G-Power (3.13) a priori. Based on an α of 0.05 and power of 0.80, 76 FDMs were planned for the study assuming a medium effect size (0.15) for regression of the dependent variable (PTSD symptoms) on the three independent variables (coping strategies). A medium effect size was chosen based on previous studies examining the relationship between coping strategies and PTSD symptoms. Assuming an attrition rate of 20%, a total of 96 FDMs were required to obtain the calculated sample size of 76.