Incidence, prevalence, and timing of postpartum complications and mortality in Canada and the United States: a systematic review and meta-analysis protocol.

OBJECTIVE: The goal of this systematic review is to assess the incidence, prevalence, and timing of common postpartum (up to 1 year after delivery) medical, surgical/procedural, and psychosocial complications and mortality. INTRODUCTION: Childbirth is the most common cause for hospitalization, and cesarean delivery is the most commonly performed inpatient surgery. After delivery, mothers are at risk of short- and long-term complications that can impact their well-being. The results of this review will inform evidence-based recommendations for patient education, monitoring, and follow-up. INCLUSION CRITERIA: We will include studies performed in Canada and/or the United States that report the incidence or prevalence of medical, procedural/surgical, and psychosocial complications within 1 year postpartum. Observational studies (analytical cross-sectional studies, retrospective and prospective cohorts), randomized or non-randomized controlled trials with a control or standard of care group, systematic reviews, and meta-analyses will be included. Studies with fewer than 100 patients, participants younger than 18 years, no reporting of duration, or focus on patients with a specific condition rather than a general postpartum population will be excluded. METHODS: The search strategy was codeveloped with a medical librarian and included full-text English-language articles published within the past 10 years (2011-2021) in PubMed, CINHAL, Web of Science, and Cochrane Database of Systematic Reviews. Screening, critical appraisal, and data extraction will be performed by two independent reviewers using Covidence, standardized JBI tools, and a standardized form, respectively. For each complication, the incidence or prevalence, timing of the frequency measurement, and duration of follow-up from individual studies will be determined. Meta-analysis will be performed if feasible. SYSTEMATIC REVIEW REGISTRATION NUMBER: PROSPERO CRD42022303047.

Prediction of Opioid Analgesic Efficacy by Measurement of Pupillary Unrest.

BACKGROUND: Pupillary unrest under ambient light (PUAL) is the fluctuation in pupil diameter in time around a mean value. PUAL is augmented by light and diminished by administration of opioids. We hypothesized that, because pupillary unrest is a marker of opioid effect, low levels of PUAL may be associated with reduced opioid efficacy, as measured by changes in the numerical rating scale (NRS) pain scores of patients in the postanesthesia care unit (PACU). METHODS: We used an infrared pupillometer to measure PUAL in patients recovering from ambulatory surgery at 2 different institutions. At both sites, PUAL was quantified using spectral analysis of the Fourier transform of pupil diameter versus time. We measured PUAL and pain scores before and after opioid administration. Protocols for total capture time and lighting conditions varied between the 2 sites. Correlations between PUAL and change in NRS scores were examined using significance testing of Pearson correlation coefficients. Correlations between change in PUAL and change in NRS scores were also examined. Patients were divided into high and low PUAL groups, and high and low response to opioid. A Fisher exact test was used to determine whether there was a significant association between PUAL and opioid response. RESULTS: For patients with pain in the PACU, low levels of pupillary unrest before opioid therapy were associated with minimal or no reduction in pain scores after opioid administration. We noted a significant correlation at both sites between PUAL and pain score reduction with opioids (r = 0.59, P = .0053, and r = 0.57, P = .022.) The Fisher exact test confirmed that patients with PUAL levels above the mean had a more beneficial analgesic effect from opioids than those with low PUAL levels (P = .018). We also noted that change in PUAL was significantly correlated with change in pain score at both sites (r = 0.56, P = .03 and r = 0.55, P = .01). CONCLUSIONS: We observe that the pretreatment magnitude of PUAL is correlated with the analgesic response to opioid therapy, and that patients who exhibit higher levels of PUAL change after opioid administration have a more beneficial analgesic effect from opioids. Larger studies with uniform measurement protocols are required to confirm these preliminary results.