Comparison of pre-filter and post-filter ionised calcium monitoring in continuous veno-venous hemodiafiltration (CVVHD-F) with citrate anti-coagulation.

BACKGROUND: It is widespread practice during citrate anticoagulated renal replacement therapy to monitor circuit ionised calcium (iCa2+) to evaluate the effectiveness of anticoagulation. Whether the optimal site to sample the blood path is before or after the haemofilter is a common question. METHODS: Using a prospectively collected observational dataset from intensive care patients receiving pre-dilution continuous veno-venous haemodiafiltration (CVVHD-F) with integrated citrate anticoagulation we compared paired samples of pre and post filter iCa2+ where the target range was 0.3-0.5 mmol.L-1 as well as concurrently collected arterial iCa2+. Two nested mixed methods linear models were fitted to the data describing post vs pre filter iCa2+, and the relationship of pre, post and arterial samples. SETTING: An 11 bed general intensive care unit. PARTICIPANTS: 450 grouped samples from 152 time periods in seven patients on CRRT with citrate anticoagulation. RESULTS: The relationship of post to pre-filter iCa2+ was not 1:1 with post = 0.082 + 0.751 x pre-filter iCa2+ (95% CI intercept: 0.015-0.152, slope 0.558-0.942). Variation was greatest between patients rather than between circuits within the same patient or citrate dose. Compared to arterial iCa2+ there was no significant difference between pre and post-filter sampling sites (F-value 0.047, p = 0.827). CONCLUSION: These results demonstrate that there is minimal difference between pre and post filter samples for iCa2+ monitoring of circuit anticoagulation in citrate patients relative to the arterial iCa2+ in CVVHD-F however compared to pre-filter sampling, post filter sampling has a flatter response and greater variation.

Danger at every rung: Epidemiology and outcomes of ICU-admitted ladder-related trauma.

INTRODUCTION: The incidence of ladder-related falls is increasing, and this represents a disturbing trend, particularly in the context of increased life expectancy and the impending retirement of the populous 'baby-boomer' generation. To date, there have been no critical illness-focused studies reporting on the incidence, severity and outcomes of severe ladder-related injuries requiring ICU management. METHODS: Major trauma patients admitted to ICU over a 5year period to June 2011 after ladder falls >1m were identified from prospectively collected trauma data at a Level 1 trauma service. Demographic and ICU clinical management data were collected and non-parametric statistical analyses were used to explore the relationships between variables in hospital mortality/survival. RESULTS: There were 584 ladder fall admissions, including 194 major trauma cases, of whom 29.9% (n=58) fell >1m and were admitted to ICU. Hospital mortality was 26%, and fatal cases were almost entirely older males in domestic falls of ≤3m who died as a result of traumatic brain injury. Non-survivors had lower GCS at the scene (p=0.02), higher AIS head code (p=0.01), higher heart rate and lower mean arterial pressure (p<0.01) in the initial 24h period in ICU, and were ≥55years of age (p=0.05). Only 46% of patients available for follow-up were living at home at 12months without requiring additional care. CONCLUSIONS: The incidence of ladder falls requiring ICU management is increasing, and severe traumatic brain injury was responsible for the majority of deaths and for poor outcomes in survivors. In-hospital costs attributable to the care of these patients are high, and fewer than half were living independently at home at 12months post-fall. A concerted public health campaign is required to alert the community to the potential consequences of this mechanism of injury. The use of helmets for ladder users in domestic settings, where occupational health and safety regulations are less likely to be applied, is strongly recommended to mitigate the risk of severe brain injury. The benefits of this simple strategy far outweigh any mild inconvenience for the wearer, and may prevent catastrophic injury.

Randomised trial of software algorithm driven regional citrate anticoagulation versus heparin in continuous renal replacement therapy: the Filter Life in Renal Replacement Therapy pilot trial.

OBJECTIVE: The effectiveness of continuous renal replacement therapy (CRRT) increases when unplanned circuit failure is prevented. Adequate anticoagulation is an important component. Although heparin is the predominating anticoagulant, calcium chelation with citrate is an alternative, but systemic calcium monitoring and supplementation increase the complexity of CRRT. We assessed efficacy and safety of citrate delivery via integrated software algorithms against an established regional heparin protocol. DESIGN: Prospective computer randomisation allocated eligible patients to regional citrate or heparin between April and December 2012. Citrate fluids were Prismocitrate 18 mmol/L predilution and Prism0cal B22 dialysate. Hemosol B0 was the default fluid for heparin. The primary outcome was filter running time. Electively terminated circuits were censored. Intention-totreat (ITT) and per-protocol analyses were performed. Filter survival was compared by log-rank tests and hazard ratios were explored with a mixed-effects Cox model. RESULTS: 221 filters were analysed from 30 patients (of whom 19 were randomly allocated to citrate filters and 11 to heparin filters). Patients randomly allocated to citrate were older, sicker, with a higher male:female ratio, but of similar weight. Mortality was 37% in the citrate arm and 27% in the heparin arm. All deaths were attributed to underlying disease. Significant crossover occurred from the citrate arm to use of heparin. Median filter survival, by ITT, was not significantly different (citrate, 34 hours; heparin, 30.7 hours; P=0.58). Per-protocol survival favoured citrate (citrate, 42.1 hours; heparin, 24 hours; χ(2)=8.1; P=0.004). Considerable variation in filter life existed between patients, and between vascular access sites within patients. Safety end points were reached in one heparin and three citrate patients. CONCLUSION: Although the per-protocol results favoured citrate when it was actually delivered, the significant crossover between treatment arms hampered more definitive conclusions. Until further studies support improved patient outcomes, increased complexity and complications suggest that anticoagulation choice be made using patient-specific indications.