Lactate clearance metrics are not superior to initial lactate in predicting mortality in trauma.

PURPOSE: Despite the availability of different lactate clearance (LC) metrics for clinical use, it remains unknown which metric is superior as a clinical predictor for outcome, particularly in trauma patients. This retrospective study compared four previously described metrics of LC and examined the association between LC and outcome in trauma patients. METHODS: Lactate values of trauma patients admitted to a level I trauma center between 2010 and 2013 were retrieved from patient records. LC was calculated according to Huckabee, Regnier et al., Billeter et al. and Zhang et al. Patients were categorized as isolated traumatic brain injury (TBI), trauma with TBI, and trauma without TBI. The primary study outcome was in-hospital mortality. RESULTS: 367 trauma patients were eligible for LC calculation. Only LC by Zhang et al. [area under the curve (AUC) > 0.622, p < 0.01], and Billeter et al. (AUC > 0.616, p < 0.05) were predictive for mortality in trauma patients with and without TBI. However, both were equally prognostic as the initial lactate value for in-hospital mortality. The prognostic value of initial lactate and lactate clearance for in-hospital mortality were not found to differ between isolated TBI, polytrauma with TBI, and trauma without TBI. CONCLUSIONS: LC metrics based on the methods of Zhang et al. and Billeter et al. predicted mortality in trauma patients, and their prognostic value did not differ between patients with and without TBI. However, initial lactate value was equally prognostic as these LC metrics. Our findings suggest that a single initial lactate measurement may be a more clinically useful tool to predict mortality than the calculation of lactate clearance.

Total loss and distribution of nitrogen and phosphorus in the outdoor run of organic laying hens.

1. The objective of this study was to determine the level and variation of the total mass, and load of nitrogen (N) and phosphorus (P) excreted into the outdoor run of organic egg production systems. 2. Three egg production farms with an aviary system and an outdoor run were selected for this study. Four measurements, one per season, were executed on each farm. 3. Mean content of N and P of a manure dropping was 14·0 g N kg⁻¹ and 3·12 g P kg⁻¹, mean mass of a dropping was 6·36 g and mean dry matter content of a dropping was 238 g kg⁻¹. Mean rate of excretion in the outdoor run was 2·99 droppings per hen per h. Mean percentage of hens outside during the time the outdoor run could be accessed was lowest on Farm 1 (1·7%), highest on Farm 2 (16·0%), and intermediate on Farm 3 (7·1%). 4. On all farms an exponential decrease of the number of hens and of the load of N and P with increasing distance from the hen house was found. Load of N exceeded the fertilisation standard (of 170 kg ha⁻¹y⁻¹) in the region at a 0 to 19 m distance from the hen house on Farm 1, 0 to 146 m on Farm 2 and 0 to 52 m on Farm 3. 5. It is concluded that the husbandry system should be redesigned to solve the problem of overloading, unwanted loss of N and P to the environment and loss of N and P from the organic production cycle.