Association of Preoperative Pulse Pressure and Oxygen Delivery Index During Cardiopulmonary Bypass With Postoperative Acute Kidney Injury.

OBJECTIVE: To investigate if oxygen delivery index during cardiopulmonary bypass (DO2I) was more strongly associated with acute kidney injury (AKI), the higher the patient's preoperative pulse pressure (PP). DESIGN: Retrospective cohort of 1064 patients undergoing cardiac surgery. SETTING: Single academic healthcare center. PARTICIPANTS: Adult patients undergoing coronary artery bypass grafting, valve, aortic, or combined surgery requiring cardiopulmonary bypass. INTERVENTIONS: Hemoglobin, arterial oxygen saturation, and pump flow recorded no fewer than every 30 min were extracted from the patients' perfusion records, and DO2I was calculated. The AKI was assessed from the pre- and postoperative creatinine and urine output values using the Acute Kidney Injury Network criteria. The sample was stratified in 5 categories of progressively higher PP. The patient characteristics and intraoperative variables were evaluated in univariate analysis for a relationship with AKI. The significant risk factors from the univariate analysis then were evaluated in a multivariate analysis and assessed for logistic fit with respect to AKI. PRIMARY OUTCOME: The AKI assessed as a binary outcome. MEASUREMENTS AND MAIN RESULTS: Age, body surface area, DO2I, history of heart failure, and baseline creatinine were associated significantly with AKI, as was an interaction term between the PP category and DO2I (p = 0.0067). The higher the PP category, the stronger the observed association between DO2I and AKI, and the higher the variability in the predicted risk of AKI dependent on DO2I. CONCLUSIONS: A lower DO2I during cardiopulmonary bypass appeared more strongly associated with a higher likelihood of developing AKI, the higher the patient's preoperative pulse pressure.

Heart Rate Variability Biofeedback Improves Emotional and Physical Health and Performance: A Systematic Review and Meta Analysis.

We performed a systematic and meta analytic review of heart rate variability biofeedback (HRVB) for various symptoms and human functioning. We analyzed all problems addressed by HRVB and all outcome measures in all studies, whether or not relevant to the studied population, among randomly controlled studies. Targets included various biological and psychological problems and issues with athletic, cognitive, and artistic performance. Our initial review yielded 1868 papers, from which 58 met inclusion criteria. A significant small to moderate effect size was found favoring HRVB, which does not differ from that of other effective treatments. With a small number of studies for each, HRVB has the largest effect sizes for anxiety, depression, anger and athletic/artistic performance and the smallest effect sizes on PTSD, sleep and quality of life. We found no significant differences for number of treatment sessions or weeks between pretest and post-test, whether the outcome measure was targeted to the population, or year of publication. Effect sizes are larger in comparison to inactive than active control conditions although significant for both. HRVB improves symptoms and functioning in many areas, both in the normal and pathological ranges. It appears useful as a complementary treatment. Further research is needed to confirm its efficacy for particular applications.