Platelets are used in critical to either prevent or treat bleeding. The problem is that despite all the research and studies we still don't know that much on the best way to clinically use platelets... and they are tricky indeed:
- Platelets must be stored at room temperature
- Because of the risk of bacterial growth the shelf life of platelet units is only 5 days
- Maintaining a constant pool of platelets for clinical work is extremely difficult and resource-intensive
- Transfusion related risks are notable (e.g. febrile reaction 1/14, allergic reactions 1/50, bacterial sepsis 1/75'000)
When it comes to their usage intensivists often have a different approach than haematologists and guidelines mostly vary from hospital to hospital, from country to country. However, instead of searching all the literature yourself you might consider reading the article by Kaufman RM et al. published just this month in the Annals of Internal Medicine.
A panel of 21 specialists, covering almost all areas of medicine involved in handling platelets, performed a systematic review by looking up publications from 1900 to 2013. From 1024 identified studies, 17 RCTs and 53 observational studies were included in the review. The result of their work are guidelines on the use of platelets including their grade of recommendation. Short:
- Platelets should be transfused prophylactically to reduce the risk for spontaneous bleeding in hospitalized adult patients with therapy-induced hypo proliferative thrombocytopenia < 10 x 109 cells/L (Grade: strong recommendation; moderate-quality evidence)
- Platelets should be transfused prophylactically for patients having elective central venous catheter placement with a platelet count less than 20 × 109 cells/L (Grade: weak recommendation; low-quality evidence)
- Prophylactic platelet transfusion is recommended for patients having elective diagnostic lumbar puncture with a platelet count less than 50 × 109 cells/L (Grade: weak recommendation; very low-quality evidence)
- Prophylactic platelet transfusion is recommended for patients having major elective nonneuraxial surgery with a platelet count less than 50 × 109 cells/L (Grade: weak recommendation; very low-quality evidence)
- Routine prophylactic platelet transfusion for patients who are nonthrombocytopenic and have cardiac surgery with cardiopulmonary bypass (CPB) is NOT recommended. Platelet transfusion for patients having CPB who exhibit perioperative bleeding with thrombocytopenia and/or evidence of platelet dysfunction is NOT recommended (Grade: weak recommendation; very low-quality evidence)
- Recommendations for or against platelet transfusion for patients receiving antiplatelet therapy who have intracranial hemorrhage (traumatic or spontaneous) cannot be made (Grade: uncertain recommendation; very low-quality evidence)
It is remarkable to see that after a century of intense research we are left with some moderate-quality evidence and lots of low quality evidence and therefore weak recommendations. I guess guidelines will continue to vary from doctor to doctor, hospital to hospital... country to country.
Kaufman RM et al. Ann Intern Med, Nov 11, 2014: Open access article
As mentioned in one of our earlier entries two important trials (Hermanns et al. The Lancet and Caesar et al. NEJM) have indicated that early parenteral nutrition (PN) might actually be harmful and a late PN strategy should be the standard of care.
Despite this the debate has continued and remains highly controversial. This is nicely reflected in recent guidelines regarding the timing of supplemental PN. While the European Society for Clinical Nutrition and Metabolism (ESPEN) recommends PN within 24-48h in patients who are expected to be intolerant to enteral nutrition (EN), the American Society for Parenteral and Enteral Nutrition (ASPEN) recommends postponing the initiation of PN until day 8 after ICU admission.
In order to clarify things a little Bost et al. have now published a systematic review on the timing of parenteral nutrition in critical care (Open access). From 3520 initially screened articles only four randomised controlled trials and two prospective observational studies remained after critical appraisal.
"In conclusion it seems to be reasonable to assume that in critically ill patients, when full enteral support is contraindicated or fails to reach caloric targets, there are no clinically relevant benefits of early PN compared to late PN with respect to morbidity or mortality end points.
Considering that infectious morbidity and resolution of organ failure may be negatively affected through mechanisms not yet clearly understood and acquisition costs of parenteral nutrition are higher, the early administration of parenteral nutrition cannot be recommended."
The Review in one short sentence: Early PN has no advantage over late PN, but might be actually harmful.
Bost et al. Annals of Intensive Care 2014, 4:31
ESPEN Guidelines on parenteral nutrition, 2009
A.S.P.E.N. Guidelines for the provision and assessment of nutrition support therapy in the adult critically ill patient
BIJC.org on: Starting early PN weakens the critically ill
One of the key elements within antimicrobial stewardship and treatment paradigms for serious sepsis is de-escalation of antibiotic treatment. Antibiotic de-escalation describes a mechanism whereby the provision of effective initial antibiotic treatment is achieved while avoiding unnecessary antibiotic use that would promote the development of resistance. Basically it means that empirical antibiotics are stopped stopped or reduced in number and/or narrowed in spectrum on the basis of culture results. The recommendation to do so is mainly supported by observational studies only.
This makes the publication of Leone at al. in Intensive Care Medicine of last month remarkable as they are the first to present a multi-center, non-blinded, randomised non-inferiority trial on de-escalation versus continuation of empirical antimicrobial treatment in severe Sepsis.
After screening they included 120 patients of which 60 were assigned to continuation of appropriate empirical antimicrobial treatment and the other 60 to de-escalation. As a result de-escalation did not improve ICU length of stay (primary endpoint). De-escalation was associated though with an increased number of super infections (secondary endpoint), but did not affect mortality (secondary endpoint).
Despite the studies limitations (relatively small population, lack of blind treatment and some other minor details) these results come surprisingly and leave us with the conclusion:
De-escalation of antimicrobial treatment might remain standard of care at this stage but should be questioned if this is true in general.
Leone M et al. Intensive Care Med (2014) 40:1399–1408
Masterton RG, Crit Care Clin (2011), Vol 27