Acute fluid shifts influence the assessment of serum vitamin D status in critically ill patients

Introduction Recent reports have highlighted the prevalence of vitamin D deficiency and suggested an association with excess mortality in critically ill patients. Serum vitamin D concentrations in these studies were measured following resuscitation. It is unclear whether aggressive fluid resuscitation independently influences serum vitamin D. Methods Nineteen patients undergoing cardiopulmonary bypass were studied. Serum 25(OH)D3, 1α,25(OH)2D3, parathyroid hormone, C-reactive protein (CRP), and ionised calcium were measured at five defined timepoints: T1 - baseline, T2 - 5 minutes after onset of cardiopulmonary bypass (CPB) (time of maximal fluid effect), T3 - on return to the intensive care unit, T4 - 24 hrs after surgery and T5 - 5 days after surgery. Linear mixed models were used to compare measures at T2-T5 with baseline measures. Results Acute fluid loading resulted in a 35% reduction in 25(OH)D3 (59 ± 16 to 38 ± 14 nmol/L, P < 0.0001) and a 45% reduction in 1α,25(OH)2D3 (99 ± 40 to 54 ± 22 pmol/L P < 0.0001) and i(Ca) (P < 0.01), with elevation in parathyroid hormone (P < 0.0001). Serum 25(OH)D3 returned to baseline only at T5 while 1α,25(OH)2D3 demonstrated an overshoot above baseline at T5 (P < 0.0001). There was a delayed rise in CRP at T4 and T5; this was not associated with a reduction in vitamin D levels at these time points. Conclusions Hemodilution significantly lowers serum 25(OH)D3 and 1α,25(OH)2D3, which may take up to 24 hours to resolve. Moreover, delayed overshoot of 1α,25(OH)2D3 needs consideration. We urge caution in interpreting serum vitamin D in critically ill patients in the context of major resuscitation, and would advocate repeating the measurement once the effects of the resuscitation have abated.

Performance based planning in Queensland : A case of unintended plan-making outcomes

Performance based planning (PBP) is purported to be a viable alternative to traditional zoning. The implementation of PBP ranges between pure approaches that rely on predetermined quantifiable performance standards to determine land use suitability, and hybrid approaches that rely on a mix of activity based zones in addition to prescriptive and subjective standards. Jurisdictions in the USA, Australia and New Zealand have attempted this type of land use regulation with varying degrees of success. Despite the adoption of PBP legislation in these jurisdictions, this paper argues that a lack of extensive evaluation means that PBP is not well understood and the purported advantages of this type of planning are rarely achieved in practice. Few empirical studies have attempted to examine how PBP has been implemented in practice. In Queensland, Australia, the Integrated Planning Act 1997 (IPA) operated as Queensland's principal planning legislation between March 1998 and December 2009. While the IPA did not explicitly use the term performance based planning, the Queensland's planning system is widely considered to be performance based in practice. Significantly, the IPA prevented Local Government from prohibiting development or use and the term zone was absent from the legislation. How plan-making would be advanced under the new planning regime was not clear, and as a consequence local governments produced a variety of different plan-making approaches to comply with the new legislative regime. In order to analyse this variation the research has developed a performance adoption spectrum to classify plans ranging between pure and hybrid perspectives of PBP. The spectrum compares how land use was regulated in seventeen IPA plans across Queensland. The research found that hybrid plans predominated, and that over time a greater reliance on risk adverse drafting approaches created a quasi-prohibition plan, the exact opposite of what was intended by the IPA. This paper concludes that the drafting of the IPA and absence of plan-making guidance contributed to lack of shared understanding about the intended direction of the new planning system and resulted in many administrative interpretations of the legislation. It was a planning direction that tried too hard to be different, and as a result created a perception of land use risk and uncertainty that caused a return to more prescriptive and inflexible plan-making methods.