Intensive care patients are often exposed to iatrogenic anaemia, and blood-saving strategies may have a role in reducing this complication. Lately several measures have been proposed to reduce iatrogenic blood loss , but compliance has been seldom evaluated. Amanda Ullman and her team have conducted “True Blood” , a cross-sectional one-week long descriptive study, where they observed blood sampling practices in three intensive care units (ICUs) of tertiary-referral centers in Queensland, Australia.
The objectives of this study were 1. to describe current blood sampling practices in an adult, paediatric and neonatal ICUs; 2. to provide an estimate of costs associated with sampling practices; and 3. to compare local guidelines and current sampling practices in same units with international evidence based recommendations.
Each nurse of every shift documented the amount of blood, frequency and type of blood sample as well as the demographic data of the patients, such as age, severity of illness, unit LOS, primary diagnosis, ventilation, renal replacement therapy and ICU outcome. The data were based on variables and outcomes of previous studies. Severity of illness was estimated according to the PELOD2 (Paediatric Logistic Organ Dysfunction, score range 0-71) for children and neonates and according to the APACHE II score (Acute Physiology and Chronic Health Evaluation II, score range 0-79) for adults. Higher scores indicate higher level of illness and risk of mortality in both measurements.
All data were documented on locally adapted tools containing all the same variables. Locally based trained coordinators educated and oversaw the documentation of the bedside nurses. At each site the tool and the data collection was tested for feasibility for one day and adapted accordingly. The cost was based on the pricing of the Medicare Benefit Schedule for all blood samplings.
Local policies, procedural guidelines, protocols, manuals, nursing standards or work instructions served as local guidelines. Each were assessed for incorporation of the seven evidence-based blood conservation strategies recommended in the peer reviewed literature: frequent evaluation of routine sampling orders, closed-system sampling, small-volume phlebotomy tubes, non-invasive monitoring, bundled schedules of sampling, charting of daily cumulative phlebotomy loss and point of care testing.
During the study period all admitted patients (n=96) and their 940 samples were analysed. Most patients in each ICU were ventilated and admitted for at least 50 hours. Blood gases were the most frequent and mostly nurse-initiated blood tests for adults (82%), children (80%) and neonates (47%) (p<0.001). Most samplings were routine tests. The median number and volume of the samples per patient was significantly different between the three ICU settings, as adults patients for instance were sampled more frequently and with greater volumes, in particular if compared to neonates.
The neonatal and adult UCIs had specific guidelines for blood gases from arterial lines and umbilical lines (neonatal only) but not for other sampling sites. Only the paediatric ICU contained all the evidence-based recommendations in their protocols. All ICUs used non-invasive monitoring and point of care testing.
The study revealed that higher awareness to prevent unnecessary blood loss is still needed, in particular in adult settings. As showed in a recent German longitudinal study , it is possible to reduce significantly the blood loss during ICU stay by simple interventions, as the use of closed-loop arterial sampling systems. But furthermore, bedside nurses have an important role identifying sources of unnecessary blood loss and implementing blood-saving measures that could reduce iatrogenic anaemia, reduce RBC transfusions, and therefore improve patient safety and outcome.
Article review prepared and submitted by ESICM member Madeleine Bruttin, on behalf of the N&AHP Committee.
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