Changing Perspectives: Restrictive use of blood transfusion in critical care: the dawn of a new age?

Restrictive use of blood transfusion in critical care: the dawn of a new age?

Haemoglobin transports oxygen from the pulmonary capillaries to vital organs and other tissues. Acute anaemia, for example as a consequence of surgical blood loss, can lead to tissue hypoxia and organ damage. When haemoglobin concentration drops below critical levels, red blood cell (RBC) transfusion may be indicated and even lifesaving. However, RBC transfusion has also been associated with many complications, for instance transfusion reaction, infection transmission, and acute lung injury. Therefore, determining adequate transfusion triggers is of utmost importance.1 The prevailing Dutch transfusion guideline endorses the ‘4-5-6’ strategy, in which patient characteristics and clinical status influence the decision to apply RBC transfusion.2 In short, RBC transfusion is triggered by haemoglobin concentrations below 4 mmol/L in healthy adults, whereas this trigger is 6 mmol/L in cardiopulmonary restricted patients. Despite its simplicity, recent evidence suggests that the ‘4-5-6’ strategy does not benefit patient outcomes and that a more restrictive use of RBC transfusion might be beneficial. A recent, multicenter, randomized study comprising of more than five thousand cardiac surgery patients found no difference in clinical outcomes (stroke, renal failure, myocardial infarction and death) between a transfusion trigger of 4.5 and 6 mmol/L , respectively.3 Furthermore, a randomized study comprising of almost one thousand patients with acute upper gastrointestinal bleeding found an higher survival rate with a transfusion trigger of 4.3 compared to 5.5 mmol/L.1-4 Therefore, we expect that future guidelines will recommend restrictive use of RBC transfusion in critical care settings.

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Subject 101: Fundamentals and diagnostic challenges of viral hepatitis

Fundamentals and diagnostic challenges of viral hepatitis

Viral hepatitis is one of the leading causes of liver cirrhosis and hepatocellular carcinoma worldwide.1 Although the incidence rates in the Netherlands for viral hepatitis are low, the inhabitancy of populations from high-risk areas (sub-Saharan Africa, Asia) and the intensified travel habits of the Dutch population towards such places warrants adequate knowledge of this topic.2,3

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Trial and Error: Understanding an uncommon fracture

Understanding an uncommon fracture

“No, our family is not supported by a social worker.” Jesse’s mother is visibly annoyed now. “Jesse* is a very energetic child, but we are doing fine.” Jesse, a heated, whining toddler of 16 months old, showed up at the emergency department in his pyjamas tonight. His mother explained that his leg got stuck between the bars of his bed. Now it hurts badly, and the emergency physician found a spiral shaft fracture of the tibia on the X-ray. Our conversation becomes increasingly unfriendly, and after fifteen minutes, she loudly screams that she is not a criminal and takes Jesse home. Communication has broken down making it impossible to further investigate the worries of the emergency physician about possible abuse. We feel forced to report the case to the national child protection agency.

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Changing Perspectives: Tonsillectomy and its implications for anesthetic management

Tonsillectomy and its implications for anesthetic management

Many children with complaints of upper airway obstruction undergo a tonsillectomy. Dr. Sluder (1865-1928) first described this procedure in 1911, which includes the use of a blunt guillotine.1 He was able to remove both tonsils in less than 10 seconds. General anesthesia was extremely dangerous at the time. Therefore, this technique was performed in non-intubated children, mostly with the use of local anesthetics, and sometimes without any anesthetics.

Over many years, Sluder’s method made way for a nowadays daily used dissection technique in which intubation is necessary. In this procedure, a free airway is guaranteed throughout the whole operation. Moreover, the surgeon is able to perform the tonsillectomy more carefully, and as a result the hemostasis of the operational area can be monitored more precisely. However, this technique is more cumbersome and has an increased procedural time.

Sluder’s operation is still performed in some Dutch hospitals. Current guidelines recommend that his technique should only be performed in non-intubated children by competent anesthesiologists and ENT specialists.2  The airway is considered unsafe due to the possibility of aspiration of tissue and blood. Moreover, this very painful stimulus is performed during sub-anesthetic threshold values of volatile anesthetics, which may lead to acute laryngospasm, resulting in a ‘cannot ventilate’ situation in a patient without intravenous access. In addition, anesthesiologists lose their competence as this method disappears in their education. Thus, in our opinion, the classic dissection technique is ought to replace Sluder’s operation in non-intubated children.

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Expert Opinion: High intelligence is inversely related to problems related to ADHD

High intelligence is inversely related to problems related to ADHD

Background

High intelligence scores have been associated with positive outcomes, such as better behavioural, cognitive and emotional control in addition to good academic performance and improved mental and physical health and mortality.1 However, several studies have found high intelligence scores and superior school performance to correlate with a predisposition towards developing bipolar disorder, psychosis and schizophrenia.2-4 For attention-deficit hyperactivity disorder (ADHD) it is argued that high intelligence is inherently related to high activity levels, low impulse control, boredom, frustration and poor attention span. Although, it has also been stated that these problems are not characteristic for ADHD as they are non-pervasive and solely specific for situations that evoke boredom and frustration. Conversely, it is hypothesized that ADHD is underdiagnosed in highly intelligent individuals as high intellect may mask ADHD problems and cognitive deficits. These opposing hypotheses have been heavily debated and not studied methodically. For this Expert Opinion article, the methodology and relevance of the first large general population based study on the relation between intelligence and ADHD problems related to ADHD will be reviewed.

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Editorial: Data mining to uncover patterns in data

Data mining to uncover patterns in data

P-hacking, data dredging, data fishing. These terms imply use of data mining to uncover patterns in data that can be presented as statistically significant, without first devising a specific hypothesis as to the underlying causality.1 An example: the number of people who drowned by falling into a pool correlates with the number movies Nicolas Cage appeared in from 1999 to 2009 (r=0.67).2 This seems bizarre but these kind of practices, in a far more subtle way of course, occur in research groups. Data files are thoroughly analyzed in the hope of finding significant results. P-hacking is often followed by HARKing (hypothesizing after the results are known), which defies the founding principles of empiricism.3 The hypothesis and method get altered after the results are analyzed instead of the other way around. The incentive for this behavior is driven by many factors; for instance by the amount of pressure to publicize and journals mostly publishing positive results. These malpractices have already been described in statistical literature in the previous century, but the awareness slowly seems to increase in medical sciences. Different solutions to tackle these problems are named; using ‘clinical relevance’ instead of ‘significant’ results, preregistering research plans before collecting data and all kinds of statistical solutions.4 I would like to encourage students to study these ideas

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