Seminars in perinatology
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Seminars in perinatology · Oct 2012
ReviewThe influence of analgesia on labor--is it related to primary cesarean rates?
Multiple observational studies have reported an association between neuraxial (epidural, spinal, or combined spinal-epidural) labor analgesia and cesarean delivery. The purpose of this review is to summarize data from controlled trials addressing the question of whether neuraxial labor analgesia causes an increased risk of cesarean delivery. Additionally, the review will discuss whether the timing of initiation of analgesia or the specific type of neuraxial analgesia influences mode of delivery. Finally, the issue of external validity of published trials will be discussed.
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Seminars in perinatology · Aug 2012
ReviewNeurodevelopmental outcome of extremely low-birth-weight infants randomly assigned to restrictive or liberal hemoglobin thresholds for blood transfusion.
Surviving extremely low-birth-weight infants are at risk of severe neurodevelopmental disability. Transfusion with packed red cells is almost universal in the care of these infants, but the hemoglobin threshold at which these transfusions should be given is unclear. ⋯ The childhood studies favor the restrictive strategy, but include major methodological problems of secondary recruitment. No firm conclusion can be reached, other than to report that serious adverse effects may be attributable to one or other of these strategies, that prudent practice is to remain within trial protocols, and that further redesigned clinical trials are required.
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Seminars in perinatology · Aug 2012
ReviewRed blood cell transfusion: decision making in pediatric intensive care units.
The results of the Transfusion Requirements in Pediatric Intensive Care Unit study suggest that a red blood cell transfusion is not required in stable or stabilized pediatric intensive care unit children as long as their hemoglobin level is >7 g/dL. Subgroup analyses suggest that this recommendation is also adequate for stable critically ill children with a high severity of illness, respiratory dysfunction, acute lung injury, sepsis, neurological dysfunction, severe head trauma, or severe trauma, and during the postoperative period, for noncyanotic patients older than 28 days. A small randomized clinical trial suggests that a hemoglobin level of 9 g/dL is safe in the postoperative care of children with single-ventricle physiology undergoing cavopulmonary connection. Although there is consensus that blood is clearly indicated for the treatment of hemorrhagic shock, the clinical determinants that should prompt pediatric intensivists to prescribe a red blood cell transfusion to unstable PICU children are not well characterized.
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Seminars in perinatology · Aug 2012
ReviewInternational survey of transfusion practices for extremely premature infants.
Our objective was to survey neonatologists regarding international practice of red cell transfusion thresholds for premature infants with <1000-g birth weight and/or <28-week gestation. An invitation to fill out an 11-question web-based survey was distributed to neonatologists through their professional societies in 22 countries. Physicians were asked about which specific factors, in addition to hemoglobin levels, influenced their decisions about transfusing premature infants. ⋯ Step-wise increments in the median hemoglobin cutoffs directly paralleled an increase in the need for levels of respiratory support. In the first week of life, there was a wider range in the distribution of hemoglobin transfusion thresholds for infants requiring no respiratory support and full mechanical ventilation compared with the thresholds used in the second, third, and fourth weeks of life. An international survey using hypothetical scenarios shows that red blood cell transfusion practices vary widely among practicing neonatologists in participating countries.
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Seminars in perinatology · Aug 2012
ReviewEffect of processing and storage on red blood cell function in vivo.
Red blood cell (RBC) transfusion is indicated to improve oxygen delivery to tissue, and for no other purpose. We have come to appreciate that donor RBCs are fundamentally altered during processing and storage in a manner that both impairs oxygen transport efficacy and introduces additional risk by perturbing both immune and coagulation systems. ⋯ Our appreciation of other storage lesion features has emerged with improved understanding of coagulation, immune, and vascular signaling systems. Here, we review key features of the "storage lesion." Additionally, we call particular attention to the newly appreciated role of RBCs in regulating linkage between regional blood flow and regional O(2) consumption by regulating the bioavailability of key vasoactive mediators in plasma, and discuss how processing and storage disturb this key signaling function and impair transfusion efficacy.