1.
Impact of time and distance on outcomes following tourniquet use in civilian and military settings: A scoping review
Joarder M, Noureddine El Moussaoui H, Das A, Williamson F, Wullschleger M
Injury. 2023
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Editor's Choice
Abstract
BACKGROUND The last two decades have seen the reintroduction of tourniquets into guidelines for the management of acute limb trauma requiring hemorrhage control. Evidence supporting tourniquet application has demonstrated low complication rates in modern military settings involving rapid evacuation timeframes. It is unclear how these findings translate to patients who have prolonged transport times from injury in rural settings. This scoping review investigates the relationship between time and distance on metabolic complications, limb salvage and mortality following tourniquet use in civilian and military settings. METHODS A systematic search strategy was conducted using PubMed, Embase, and SafetyLit databases. Study characteristics, setting, mechanism of injury, prehospital time, tourniquet time, distance, limb salvage, metabolic response, mortality, and tourniquet removal details were extracted from eligible studies. Descriptive statistics were recorded, and studies were grouped by ischemia time (< 2 h, 2-4 h, or > 4 h). RESULTS The search identified 3103 studies, from which 86 studies were included in this scoping review. Of the 86 studies, 55 studies were primarily in civilian environments and 32 were based in military settings. One study included both settings. Blast injury was the most common mechanism of injury sustained by patients in military settings (72.8% [5968/8200]) followed by penetrating injury (23.5% [1926/8200]). In contrast, in civilian settings penetrating injury was the most common mechanism (47.7% [1633/3426]) followed by blunt injury (36.4% [1246/3426]). Tourniquet time was reported in 66/86 studies. Tourniquet time over four hours was associated with reduced limb salvage rates (57.1%) and higher mortality rates (7.1%) compared with a tourniquet time of less than two hours. The overall limb salvage and mortality rates were 69.6% and 6.7% respectively. Metabolic outcomes were reported in 28/86 studies with smaller sample sizes and inconsistencies in which parameters were reported. CONCLUSION This scoping review presents literature describing comparatively safe tourniquet application when used for less than two hours duration. However, there is limited research describing prolonged tourniquet application or when used for protracted distances, such that the impact of tourniquet release time on metabolic outcomes and complications remains unclear. Prospective studies utilizing the development of an international database to provide this dataset is required.
PICO Summary
Population
Patients in civilian and military settings who had a tourniquet applied for the management of acute limb trauma (86 studies).
Intervention
Scoping review investigating the relationship between time and distance on metabolic complications, limb salvage and mortality following tourniquet use.
Comparison
Outcome
Most included studies (55) were based in civilian environments, 32 were based in military settings, and 1 included both settings. Blast injury was the most common mechanism of injury sustained by patients in military settings (72.8% [5968/8200]) followed by penetrating injury (23.5% [1926/8200]). In civilian settings, penetrating injury was the most common mechanism (47.7% [1633/3426]) followed by blunt injury (36.4% [1246/3426]). Tourniquet time was reported in 66/86 studies. Tourniquet time over four hours was associated with reduced limb salvage rates (57.1%) and higher mortality rates (7.1%) compared with a tourniquet time of less than two hours. The overall limb salvage and mortality rates were 69.6% and 6.7% respectively. Metabolic outcomes were reported in 28/86 studies with smaller sample sizes and inconsistencies in which parameters were reported.
2.
Higher or Lower Hemoglobin Transfusion Thresholds for Preterm Infants
Kirpalani H, Bell EF, Hintz SR, Tan S, Schmidt B, Chaudhary AS, Johnson KJ, Crawford MM, Newman JE, Vohr BR, et al
The New England journal of medicine. 2020;383(27):2639-2651
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Free full text
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Editor's Choice
Abstract
BACKGROUND Limited data suggest that higher hemoglobin thresholds for red-cell transfusions may reduce the risk of cognitive delay among extremely-low-birth-weight infants with anemia. METHODS We performed an open, multicenter trial in which infants with a birth weight of 1000 g or less and a gestational age between 22 weeks 0 days and 28 weeks 6 days were randomly assigned within 48 hours after delivery to receive red-cell transfusions at higher or lower hemoglobin thresholds until 36 weeks of postmenstrual age or discharge, whichever occurred first. The primary outcome was a composite of death or neurodevelopmental impairment (cognitive delay, cerebral palsy, or hearing or vision loss) at 22 to 26 months of age, corrected for prematurity. RESULTS A total of 1824 infants (mean birth weight, 756 g; mean gestational age, 25.9 weeks) underwent randomization. There was a between-group difference of 1.9 g per deciliter (19 g per liter) in the pretransfusion mean hemoglobin levels throughout the treatment period. Primary outcome data were available for 1692 infants (92.8%). Of 845 infants in the higher-threshold group, 423 (50.1%) died or survived with neurodevelopmental impairment, as compared with 422 of 847 infants (49.8%) in the lower-threshold group (relative risk adjusted for birth-weight stratum and center, 1.00; 95% confidence interval [CI], 0.92 to 1.10; Pā=ā0.93). At 2 years, the higher- and lower-threshold groups had similar incidences of death (16.2% and 15.0%, respectively) and neurodevelopmental impairment (39.6% and 40.3%, respectively). At discharge from the hospital, the incidences of survival without severe complications were 28.5% and 30.9%, respectively. Serious adverse events occurred in 22.7% and 21.7%, respectively. CONCLUSIONS In extremely-low-birth-weight infants, a higher hemoglobin threshold for red-cell transfusion did not improve survival without neurodevelopmental impairment at 22 to 26 months of age, corrected for prematurity. (Funded by the National Heart, Lung, and Blood Institute and others; TOP ClinicalTrials.gov number, NCT01702805.).
PICO Summary
Population
Preterm infants in 19 US centres (n= 1,824).
Intervention
Red-cell transfusions at higher haemoglobin threshold (n= 911).
Comparison
Red-cell transfusions at lower haemoglobin threshold (n= 913).
Outcome
Primary outcome data were available for 1,692 infants (92.8%). Of 845 infants in the higher-threshold group, 423 (50.1%) died or survived with neurodevelopmental impairment, as compared with 422 of 847 infants (49.8%) in the lower-threshold group. At 2 years, the higher- and lower-threshold groups had similar incidences of death 16.2% and 15.0%, respectively and neurodevelopmental impairment 39.6% and 40.3%, respectively. At discharge from the hospital, the incidences of survival without severe complications were 28.5% and 30.9%, respectively. Serious adverse events occurred in 22.7% and 21.7%, respectively.