Tag: guidelines

Categories : Environmental EffectsTags :

Solar Exposure Guidelines Could be Revised

On By ModernMedia
Photo by Amy Humphries on Unsplash

Previously published solar exposure guidelines for optimal vitamin D synthesis that were based on a study of skin samples may have to be revised. 

A study published in PNAS has tested the optimum ultraviolet radiation (UVR) wavelengths for human skin production of vitamin D in sunlight.

Though UVR from sunlight can cause sunburn and skin cancer, it is the most important source of vitamin D.

Public health advice on sunshine exposure balances its risk and benefit, which is not a simple task because the health outcomes from UVR exposure vary considerably with wavelength within the sun’s UVR spectrum. For example, the sun’s UVR contains less than 5% short wavelength UVB radiation but this is responsible for over 80% of the sunburn response. Each health outcome from solar exposure has its own unique wavelength dependency.

The link between specific UVB wavelengths and vitamin D production was determined more than thirty years ago in ex vivo skin samples. However, the finding is less well established, with doubts on its accuracy which compromise risk/benefit calculations for optimal solar exposure.

Researchers led by the Professor Antony Young from King’s College London measured blood vitamin D levels in 75 healthy young volunteers, before, during, and after partial or full body exposure to five different artificial UVR sources with different amounts of UVB radiation, to gauge the trade-off between solar exposure benefits, which include vitamin D synthesis, versus the risks of sunburn and skin cancer.

The results were compared against predictions from the old ex vivo vitamin D study, finding that it was not an accurate predictor of benefit from UVR exposure.

The authors’ recommendation is a systematic correction of the ex vivo wavelength dependency for vitamin D. The new study means that many risk benefit calculations for solar UVR exposure must be reviewed with a revised version of the wavelength dependency for vitamin D.

“Our study shows that risk versus benefit calculations from solar exposure may need to be re-evaluated. The results from the study are timely because the global technical committee, Commission internationale de l’éclairage, that sets UVR standards will be able to discuss the findings of this paper to re-evaluate the wavelength dependency of vitamin D. Further research from our group will determine the risk/benefit calculations.”

Professor Antony Young, King’s College London

Source: King’s College London

Categories : Cardiovascular DiseaseTags :

Cardiac Surgery Guidelines Updated with Emphasis on Patient Blood Management

On By ModernMedia
Photo by JAFAR AHMED on Unsplash

Newly updated multi-society cardiac surgery guidelines have shifted to a comprehensive blood management approach, with no longer simple recommendations on transfusion.

An update to the 2011 recommendations from the Society of Thoracic Surgeons and the Society of Cardiovascular Anesthesiologists, now in collaboration with the American Society of ExtraCorporeal Technology, and the Society for the Advancement of Patient Blood Management (SABM), has been put out. It is available online in the Annals of Thoracic Surgery.

Since the last version, there has been so much new evidence that Pierre R. Tibi, MD, of Yavapai Regional Medical Center in Prescott, Arizona, and colleagues revised or added 23 recommendations and scrapped others.

Probably the biggest change is going from ‘blood conservation’ to the broader ‘patient blood management‘ (PBM) approach, Dr Tibi told MedPage Today.

“Basically we’re considering blood as another vital organ,” he said. “Why that is important is because now we look at a patient’s blood system as an organ that needs to be assessed and treated for the sake of that organ and not simply to decide when or when not to transfuse.”

Recommendations range from preoperative assessment of bleeding risk and anaemia to intraoperative perfusion and blood salvage practices to postoperative treatment with human albumin for volume replacement.

“Most hospitals around the U.S. are acutely aware of patient blood management and, to some degree or another, are implementing many of the things we are talking about,” noted Tibi, who is the most recent past president of SABM. Nationwide, the amount of blood transfused in cardiac surgery has dropped 45% in the past 10 to 15 years but still ranges widely across centres.

A broadly endorsed guideline like this emphasising the importance of a whole-patient strategy should hopefully standardize effective practices and move insurers to cover them, he suggested.

The guideline, for example, gives preoperative assessment of anaemia and its treatment with IV iron and erythropoietin-stimulating agents, if there is time, a class IIA endorsement. Anaemia is widespread, with possibly as many as 40% of patients having it, with one in 10 being under the 8 mg/dL haemoglobin threshold.

“There is a distinct correlation between preoperative anemia and worse clinical outcomes in most studies,” the guidelines note. “Usually, the greater the anemia, the more severe the complications.”

However, preoperative anaemia is “very, very underrecognised and undertested,” Dr Tibi said. While there isn’t always time to reverse anaemia that is found before cardiac surgery, he pointed out that “most of the factors in elective heart surgery have to do with insurance and Medicare. … Oftentimes the treatment for anaemia is not covered by various entities and is too expensive for patients to cover themselves.”

Other notable updates included a class IA recommendation for red blood cell salvage with centrifugation when patients are on cardiopulmonary bypass and the addition of recommendations for the assessment and treatment of patients on anticoagulants.

The guideline, for example, says to withdraw ticagrelor (Brilinta) at least 3 days, clopidogrel (Plavix) 5 days, and prasugrel (Effient) 7 days prior to elective cardiac surgery, while other non-vitamin K oral anticoagulants (NOACs) should be stopped at least 2 days in advance.

“Despite their advantages, NOACs present some periprocedural challenges for operations with a high-risk bleeding profile,” the document says. “Available measurement assays to assess anticoagulation for NOACs are imprecise, and the availability of reversal agents is limited.”

If point-of-care testing with thrombin clotting time is available for dabigatran (Pradaxa), or anti-factor Xa assays for apixaban (Eliquis) and rivaroxaban (Xarelto), in the case of emergent surgery, the guidelines recommend their use.

Source: MedPage Today

Journal information: Tibi P, et al “STS/SCA/AmSECT/SABM update to the clinical practice guidelines on patient blood management” Ann Thor Surg 2021; DOI: 10.1016/j.athoracsur.2021.03.033.