Kaizer, Alexander

Background: Active compression-decompression cardiopulmonary resuscitation (ACD-CPR) combined with an impedance threshold device (ITD) and controlled head-up positioning, collectively termed AHUP-CPR, is associated with improved outcomes compared with conventional CPR (C-CPR). Active decompression (AD) forcibly lifts the anterior chest wall with suction after each compression, while the ITD simultaneously impedes airflow into the lungs. AD and ITD synergistically lower intrathoracic pressure during decompression, improving venous return, ventricular refilling and cardiac output. Concurrently, head-up positioning lowers intracranial pressures and improves cardiac preload. This pig study focused on the physiological role of AD during AHUP-CPR, simulating real clinical scenarios. Methods: Ten male and female farm pigs (~40 kg) were anesthetized, intubated and ventilated. Hemodynamic parameters, end-tidal CO2 (ETCO2), and biventricular pressure-volume loops were recorded continuously. Ventricular fibrillation was induced and left untreated for 10 mins. Then, after 2 min of automated C-CPR in the flat position, AHUP-CPR with a 3 cm lift above the neutral position of the chest was performed for 13 min. AD was then abruptly discontinued, restarted 1 min later, and increased incrementally every min to up to 4 cm of active lift. Data were analyzed with a linear mixed-effects model, using random intercepts for individual pigs. Results: Upon cessation of AD, coronary and cerebral perfusion pressures, compression and decompression aortic pressures, compression right atrial pressure, ETCO2, right and left ventricular preload, compliance, stroke volume and cardiac output all decreased immediately and significantly (p<0.01), whereas decompression right atrial and biventricular pressures increased. With restoration of AD, physiological parameters returned to ≥ 90% of pre-AD discontinuation values (Figures 1 and 2). Conclusion: Full chest wall lift, achieved with > 3 cm of AD, was needed to maintain and optimize hemodynamics during AHUP-CPR in pigs. After pausing AD, incremental restoration of AD resulted in nearly complete restoration of peripheral and central hemodynamic measures. These observations support the benefit of and need for ≥3 cm of AD to optimize AHUP-CPR. Effective means to generate ≥3 cm of AD should be considered when implementing and developing AHUP-CPR devices to optimize outcomes.

Abstract Aims In long QT syndrome (LQTS), primary prevention improves outcome; thus, early identification is key. The most common LQTS phenotype is a foetal heart rate (FHR) &lt; 3rd percentile for gestational age (GA) but the effects of cohort, genotype, variant, and maternal β-blocker therapy on FHR are unknown. We assessed the influence of these factors on FHR in pregnancies with familial LQTS and developed a FHR/GA threshold for LQTS. Methods and results In an international cohort of pregnancies in which one parent had LQTS, LQTS genotype, familial variant, and maternal β-blocker effects on FHR were assessed. We developed a testing algorithm for LQTS using FHR and GA as continuous predictors. Data included 1966 FHRs at 7–42 weeks’ GA from 267 pregnancies/164 LQTS families [220 LQTS type 1 (LQT1), 35 LQTS type 2 (LQT2), and 12 LQTS type 3 (LQT3)]. The FHRs were significantly lower in LQT1 and LQT2 but not LQT3 or LQTS negative. The LQT1 variants with non-nonsense and severe function loss (current density or β-adrenergic response) had lower FHR. Maternal β-blockers potentiated bradycardia in LQT1 and LQT2 but did not affect FHR in LQTS negative. A FHR/GA threshold predicted LQT1 and LQT2 with 74.9% accuracy, 71% sensitivity, and 81% specificity. Conclusion Genotype, LQT1 variant, and maternal β-blocker therapy affect FHR. A predictive threshold of FHR/GA significantly improves the accuracy, sensitivity, and specificity for LQT1 and LQT2, above the infant’s a priori 50% probability. We speculate this model may be useful in screening for LQTS in perinatal subjects without a known LQTS family history.

SummaryBackgroundAlthough obesity affects approximately one in five youths, only a fraction is treated in pediatric weight management clinics. Characteristics distinguishing youth with obesity who seek weight management treatment from those who do not are largely unknown. Yet identification of specific health characteristics which differentiate treatment‐seeking from non‐treatment seeking youth with obesity may shed light on underlying motivations for pursuing treatment.ObjectivesCompare the cardiometabolic profiles of an obesity treatment‐seeking sample of youth to a population‐based sample of youth with obesity, while controlling for body mass index (BMI).MethodsThis cross‐sectional study included participants, ages 12–17 years, with obesity from the Pediatric Obesity and Weight Evaluation Registry (POWER) and National Health and Nutrition Examination Survey, representing the treatment‐seeking and population samples, respectively. Mean differences were calculated for systolic and diastolic blood pressure percentiles, total cholesterol, low‐density and high‐density lipoprotein‐cholesterol, triglycerides, fasting glucose, glycated hemoglobin and alanine aminotransferase, while adjusting for age, sex, race/ethnicity, insurance status, and multiple of the 95th BMI percentile.ResultsThe POWER and National Health and Nutrition Examination Survey cohorts included 1,823 and 617 participants, respectively. The POWER cohort had higher systolic blood pressure percentile (mean difference 17.4, 95% confidence interval [14.6, 20.1], p < 0.001), diastolic blood pressure percentile (21.8 [19, 24.5], p < 0.001), triglycerides (42.3 [28, 56.5], p < 0.001) and alanine aminotransferase (7.5 [5.1, 9.8], p < 0.001) and lower fasting glucose (−6.9 [−8.2, −5.6], p < 0.001) and high‐density lipoprotein‐cholesterol (−2.3 [−3.8, −0.9], p < 0.002). There were no differences in total cholesterol or low‐density lipoprotein‐cholesterol or clinical differences in glycated hemoglobin.ConclusionFor a given BMI, obesity treatment‐seeking youth are more adversely affected by cardiometabolic risk factors than the general population of youth with obesity. This suggests that treatment‐seeking youth may represent a distinct group that is at particularly high risk for the development of future cardiometabolic disease.

ObjectiveTo assess the safety and efficacy of short‐term meal replacement therapy followed by topiramate for body mass index (BMI) reduction in adolescents with severe obesity.MethodsAdolescents (ages 12–18 years) with severe obesity (BMI ≥1.2 times the 95th percentile or BMI ≥35 kg/m2) were recruited for this double‐blind, randomized, placebo‐controlled trial. Participants completed 4 weeks of meal replacement therapy followed by randomization (1:1) to either 24 weeks of topiramate 75 mg/day or placebo. Mean changes were compared between groups.ResultsThirty adolescents (mean age 15.2 ± 1.7 years, mean BMI 40.3 ± 4.6 kg/m2) completed the meal replacement phase and were randomized; 21 completed the study. The difference in mean percent change in BMI between the topiramate and placebo groups was not significant (−1.9%; 95% CI: −5.2% to +1.5%; P = 0.291). Significant improvements in visceral fat and very‐low‐density lipoprotein cholesterol were observed in the topiramate compared with the placebo group. There were no concerning changes in neurocognitive function or bone health.ConclusionsIn this pilot study, 4 weeks of meal replacement therapy followed by 24 weeks of low‐dose topiramate compared with meal replacement therapy alone did not result in significant BMI reduction for adolescents with severe obesity.