The study was approved by the University of Pittsburgh IRB and written informed consent was obtained from both resident and patient participants. Residents at the post-graduate year level 2 or 3 were approached and enrolled at the beginning of their two-month obstetric anesthesia subspecialty rotation, on the first orientation day prior to patient care. Residents at our institution train together in groups of 3–4 on these subspecialty rotations. Rather than randomizing each individual resident to the two study groups, which would have risked group/education contamination within each rotation time, an interrupted time series approach was taken. In this approach, standardized education on PCEA, or typical orientation without formal education on patient education for PCEA, was alternated en bloc every two months for a total of 8 months, or 4 rotation cycles (Fig. 1).
In the education group (Group E), immediately after enrollment, residents were given a didactic lecture covering key points for patients to understand about PCEA. The lecture was given by an attending anesthesiologist with obstetric anesthesia subspecialty training expertise and more than 5 years of clinical practice experience (GL). Residents were taught the “teach back” method12, a well-described and effective method of clinician-patient communication. The “teach-back” method of patient education has been shown to improve patient comprehension and adherence for treatment plans12. Verbal practice/role play then occurred between each resident and the instructor GL until proficiency was achieved. Proficiency was evaluated by the instructor GL and defined as 1) each major patient teaching point delivered, unprompted, by the resident; plus 2) “teach back” method consistently demonstrated by resident at the end of patient education (“I want to be sure that I explained everything to you correctly. Can you tell me how you are going to use this button?”). Supplemental Material 1 includes all details of didactic instruction and “teach back” that was used to assess proficiency.
In the standard orientation control group (Group C), no formal teaching on PCEA was undertaken.
After the first orientation day and for the entire rotation period, patients cared for by enrolled residents were approached, enrolled, and followed by a separate investigator not involved with the education or rotation process (AP). The following endpoints were measured: total bupivacaine consumption during labor (mg), comprehension of PCEA goals, satisfaction with anesthesia care, and satisfaction with the birth experience. The validity of the local anesthetic consumption endpoint is exemplified by numerous studies that have evaluated this endpoint and its importance to obstetric outcomes; further, lower local anesthetic dose in labor has been tied to lower risk for motor block, instrumental delivery, and obstetric nerve palsies9–11,13. The patient comprehension scores were directly derived from the Group E educational intervention, in that each teaching point corresponded to a true/false question that was then completed by the patient (Supplemental Material 1). Patient satisfaction with childbirth was evaluated by the Women’s Views of Birth Labor Satisfaction Questionnaire (WOMBLSQ)14 instrument. The WOMBLSQ measures maternal satisfaction with childbirth that consists of multidimensional assessments, including expectations of labor, pain relief in labor, labor environment, and sense of control in labor. It possesses good reliability and validity for these constructs. Maternal satisfaction with anesthetic care was assessed by modified Maternal Satisfaction Scale (MSS)15, a valid and reliable tool for maternal satisfaction that specifically assesses the anesthesia dimension with a 100 mm visual analogue scale.
For the resident participants, at the beginning of the rotation all residents answered the following question: “Overall, how confident are you now in educating obstetric patients on using patient-controlled epidural analgesia (PCEA)?” The question was marked with a 100 mm line, where 0 mm indicated “not confident at all” and 100 mm indicated, “the most confidence imaginable.” At the end of the rotation, residents answered the same question that self-rated their confidence in teaching patients how to use PCEA on the 100 mm visual analog scale.
Labor Analgesia.
The standard approach to labor epidural analgesia at our institution was unchanged during the study period. Typically, after confirmed loss of resistance to saline, epidural analgesia is initiated with 8 mL bupivacaine 0.083% with 2mcg/mL fentanyl. Maintenance of epidural analgesia is with bupivacaine 0.083% with 2mcg/mL fentanyl at a background rate of 8 mL per hour, with a patient demand by button (PCEA) permitted every 8 minutes equal to 8 mL of the same solution, and a total volume permitted of 24 mL per hour. Adjustments to these doses are made at the discretion of the attending anesthesiologist during evaluations made throughout labor for the need for supplemental epidural boluses.
Statistical Analysis.
The sample size calculation was based on prior studies using labor epidural analgesia, in which the mean and standard deviation of bupivacaine consumption per hour of labor was 12.3 ± 2.5 mg.13 A sample size of 103 patients in each group (103 patients cared for by residents who received teaching intervention, and 103 patients cared for by residents who were in the control group, for a total of 206 patients) would be required to detect a difference in local anesthetic consumption of 10% (1.23 mg) per hour, representing a clinically significant change in bupivacaine consumption. This difference would be detected with a power of 0.8 at an alpha = 0.05. We estimated a 15% exclusion rate for attrition. Thus, we aimed to follow the first 15–30 patients for whom each resident performed labor epidural analgesia until the total sample of 236 (at least 118 in each study group) was achieved.
The time series data was analyzed using segmented linear regression to assess changes in levels and trends of total bupivacaine dose before and after the educational initiatives, based on methods described in published literature16,17. The interrupted time series analysis controls for auto-correlated errors and adjusts for serial correlation (for example, the quality of patient care including patient education may simply improve over time). Using the total bupivacaine dose per individual patient over time, we fit a model to predict mean total bupivacaine dose using three variables: 1) Patient ID which was interpreted as the baseline trend as patients were enrolled sequentially over time, 2) Education interventions (demarcated according to patient ID/time of enrollment, binary variables), which was interpreted as a change immediately following the education intervention, and 3) Time after educational interventions, which we interpreted as the trend after the intervention. Segmented linear regression divided the time series in to pre- and post-educational segments. We then compared the changes in trends and levels of bupivacaine dose consumption before and after the introduction of education intervention. The level of significance was set at P < 0.05.
All analyses were performed using StataSE 15.0SE (StataCorp LP, 1985, College Station, TX) and Microsoft Excel (Microsoft, Inc, Redmond, WA). Continuous variables were compared by the paired or unpaired Student t-test (parametric distributions) or Mann-Whitney U test (non-parametric distributions). Categorical variables were analyzed using the chi-square or or Fisher's exact test, as indicated. A P < 0.05 was used to reject the null hypothesis.